FORCE blog

This blog keeps you up-to-date with our activities and also informs you about news and developments in relation to coral reef research in the Caribbean.
 

In hot water: do the warming seas affect the growth of reef building corals in the same way?

In an earlier post, Dr Iliana Chollett had looked at where the reef-building coral, Montastraea preferred to grow in relation to wave exposure. Other project partners, Dr. Juan Pablo Carricart-Ganivet and Dr. Nancy Cabanillas-Teran, from El Colegio de la Frontera Sur and Universidad Nacional Autónoma de México along with other colleagues, have also been looking at two species of Montastraea from the Caribbean to see how these mighty stony corals make their skeletons and determine whether the increase in sea temperatures affects how they build these skeletons. They are looking particularly at times when the sea becomes too hot, because then these corals have to use all their energy to stay alive.

Using a technique called optical densitometry, coral samples were sliced, dried and x-rayed to be able to look closer, as the name implies, at the corals’ density. When a new skeleton is created a thin band remains within the living tissue layer and the x-rays show the annual growth pattern of the skeletons of some massive stony corals as high and low density bands. Such banding has provided invaluable information about coral growth rates and the environmental conditions in these areas where the growth took place. Using the samples, the researchers compared the various densities of the bandings and how these bands correspond with the sea temperatures at the time. This comparison allowed them to determine a relationship between the temperature of the water and the ability and strategy for growing skeletons, depending on the type of coral. They analysed historical records of annual Adapted from calcification; A Dictionary of Environment and Conservation. Chris Park. Oxford University Press, 2007. Oxford Reference Online. Oxford University Press. Queensland University. 1 June 2010

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">calcification rates in skeletons of massive corals called P. astreoides, Montastraea faveolata, and M. franksi from the Mesoamerican Barrier Reef, and for comparison also analysed the corals Porites spp. from Great Barrier Reef Australia. Porites and Montastraea, show that they respond negatively to Encarta® World English Dictionary [North American Edition] © & (P)2009 Microsoft Corporation
 

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">thermal stress and warming trends, which may cause changes to the coral community and affect coral reef communities in different ways.

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">aragonite saturation. Aragonite is one of the ingredients that corals need for building skeletons and other marine creatures use for making shells, therefore, it is important that marine organisms can absorb enough of it from the sea water. So far, though, they have not detected any changes in the corals due to the aragonite decrease in the Mesoamerica Barrier Reef.

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">calcium carbonate that they absorb from the seawater to either grow bigger or to build thicker skeletons. These examinations showed that the Porites corals invest in “extension” which means they invest the calcium carbonate in growing faster. Therefore when the calcification rate slows down there is a decrease in this fast growth rather than a decrease in the density of the skeleton. In contrast the Montastraea corals use their calcium carbonate to build thicker (denser) skeletons but if through warming waters they cannot build these thicker skeletons, they will be at risk of being broken down, particularly during storms and hurricanes which is when coral reefs take the most beating, as they protect our coastlines from these storms. Less of these sturdy corals means that those of us who live along the coasts are in much greater danger of powerful storms and hurricanes.

The full paper can be accessed in PLoSONE: http://dx.plos.org/10.1371/journal.pone.0032859"
Photos: x-ray of coral slice, ECOSUR; bottom right: Montastraea flaveolata, George Stoyle

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Is the Caribbean warming up? Where? When?

Weather is changing. It’s not only on the news, but we can feel it ourselves. However, the weather is not changing in the same way everywhere: this is a large planet and there is a lot of variability among places.

Coral reefs are in fragile equilibrium with their environment. Increasing temperatures are tipping corals and other creatures that live on the reef beyond their optima state, where they are comfortable enough to grow and reproduce. Temperature affects when some creatures migrate as well as when they reproduce. For example, some corals spawn (photo,right) at specific times of the year based on seasonal temperatures. Too much heat could spell chaos for these life patterns. Warming waters mean trouble for reefs.

This is why in FORCE we wanted to know how fast, and when (in summer or in winter?) the Caribbean is getting warmer. To answer these questions we looked at 25 years of temperature data for the entire basin. This information was collected by satellites that are more than 800 kilometres above the surface of the earth ‘taking continuous pictures’ of the sea. We used satellite images because it is the only tool we have to look at large areas at the same time, many times a day.

After analysing this data using the best statistical methods we know of, we found out two main things. The first one is that temperatures in the Caribbean are changing at very different speeds. The eastern side of the basin is getting warmer very fast (temperatures are increasing by about 0.4°C each decade), but Florida and the Bahamas are not getting warmer in any significant way. The other interesting thing we found out was that most of the warming has been due to increases in summer rather than winter temperatures. This potentially means trouble for corals, because waters are getting warmer in the hottest season of the year, and corals don’t like it that hot. They can actually suffer from thermal stress, a type of heat stress in which they expel a beneficial algae that lives within them and this causes them to turn white (photo,right) and causing them to eventually die.

Some coral reefs are already changing because of changes in climate. We hope the information we are providing can be used by other researchers to explain the responses of marine organisms to climatic change in the region.

More detailed information can be found in our research article entitled “Seasonal and spatial heterogeneity of recent sea surface temperature trends in the Caribbean Sea and southeast Gulf of Mexico” by Iliana Chollett, Frank Müller-Karger, Scott Heron, William Skirving and Peter Mumby (http://dx.doi.org/10.1016/j.marpolbul.2012.02.016).

Photos: top right:Mark Vermeij; bottom right:Peter Mumby

 
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Using satellite data in the search for species-rich reef habitats in the Caribbean

Marine habitats play an important role in supporting biological diversity and providing services to humans (such as fish production for consumption, protection from storms, or tourism). However, not all habitats are equal. In the Caribbean, habitats dominated by a type of hard coral, Montastraea, stand out. Montastraea have a massive structure and are able to build the framework of the reef, housing hundreds of other marine organisms. These species-rich reef habitats hold the largest number of species and provide the largest number of services when compared to the other marine habitats. Pinpointing the location of Montastraea reefs is therefore an important task that can help in identifying valuable areas for conservation.

For a long time marine biologists have documented that Montastraea reefs are located in areas with calm waters, relatively protected from waves. We used this piece of anecdotal knowledge to develop a simple method to locate these important habitats in the Caribbean. The method uses satellite wind data and information on the location of land masses and reef crests to estimate wave exposure (the degree of wave action on a location). The approach is based on the reasoning that the longer the distance over which the wind blows without encountering obstructions (a piece of land, an island or a reef crest) and the stronger the wind, the larger the waves can develop and the higher their energy.

We then related our measurements of wave energy with information on the distribution of shallow habitats we got from the field. We confirmed the early belief that these species-rich habitats are present in sites with low wave energy, and drew this relationship, so people can actually use it. Our model is very accurate (81%) and, unlike other models that use many, many variables to try to explain something, uses only one variable to predict where these important habitats would be.

The research paper, led by two FORCE members from the University of Exeter (UK), Iliana Chollett and Peter Mumby, just came out in the journal Coral Reefs, and is entitled “Predicting the distribution of Montastraea reefs using wave exposure”. Although the method was developed using data for the Mesoamerican reef, it applies to the entire Caribbean. The method we proposed is not only simple, but uses datasets that are completely free. This means scientists, managers or other interested stakeholders can also use this method to determine where Montastraea reefs are located in their own management planning of their reefs and coastal areas.

You can have a look at the paper in the journal (http://dx.doi.org/10.1007/s00338-011-0867-7).

Photo top right by Mark Vermeij shows Montastraea corals

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Clustering of Caribbean hurricanes allows corals to recuperate

A recent study by our FORCE researcher Professor Peter Mumby from the University of Exeter and University of Queensland along with Professor David Stephenson and Dr Renato Vitolo at the University of Exeter's Climate Systems research centre shows the hurricanes in the Caribbean tend to occur in clusters. In other words, these tropical storms develop one storm after another across the waters of the Caribbean sea.

This isn’t good news for Caribbean people but it could be not-so-bad news for corals reefs. Anyone who has lived near a Caribbean coast knows what a huge impact hurricanes (tropical storms and full blown hurricanes) can have on a place – whether economic, social and ecological. It is quite important to try to model how often tropical storms and hurricanes form and determine the activity patterns that they develop.

The scientists mapped the hurricane occurrence using a 100 year historical record of hurricanes throughout the Americas/Caribbean. They found that around the Caribbean Sea there were short intense bursts of hurricane activity followed by relatively long quiet periods. The clustering pattern was especially strong around Florida, the Bahamas, Belize, Honduras, Haiti and Jamaica.

This type of clustering activity can be hard for the coastal communities as it doesn’t always give people a chance to recover from one storm before another one hits. Ironically, according to the modelling, over the long term the Caribbean coral reefs found this pattern of hurricane activity less damaging. The reason is that the first storm or hurricane that hits causes the most damage, but the storms that follow closely and quickly don’t really cause much additional damage. Most of the more fragile coral would have been destroyed by the first storm.

The longer quiet period that follows the cluster of activity allows the corals to recover. This period of recovery allows the corals to remain in a reasonable state before being hit by another series of storms. What this means, is that “clustering can help by giving ecosystems more time to recover from natural catastrophes”.

Unfortunately if storms were the only pressure on coral reefs, this news would be reassuring but coral reefs face so much other stresses. "Cyclones have always been a natural part of coral reef lifecycles," said Professor Mumby. "However, with the additional stresses people have placed upon ecosystems like fishing, pollution and climate change, the impacts of storms and hurricanes linger a lot longer than they did in the past."

It is important to consider the clustered nature of hurricane in order to predict the impact of storms and climate change on the coral reef ecosystem. Overly pessimistic past predictions have forecasted the collapse of coral reefs at least 10 years too early because hurricanes were assumed to occur randomly over time. Looking at a given long term rate of hurricanes (e.g., once per decade), clustered events are less damaging' because it gives ecosystems more time to recover from natural disasters.

The researchers note that these findings could also have implications for the insurance industry. "Insurance companies are a bit like ecosystems and so need time to recover after major losses - so clustering of hurricanes allows the industry to build profits before the next cluster of storm losses." said Professor Stephenson.

1st photo:NOAA; 2nd photo:NASA; 3rd photo:PCEBASE; 4th photo:Global Giving
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Fate of nutrients entering coral reefs

Hi all! My name is Joost den Haan, I am a PhD student at the University of Amsterdam, the Netherlands. My work for the FORCE project revolves around the A Dictionary of Food and Nutrition. Ed. David A. Bender. Oxford University Press 2009. Oxford Reference Online.

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">nutrification of coral reefs, hence our title ‘Fate of nutrients entering coral reefs’. We are specifically interested in the role that Herring, David. What Are Phytoplankton. NASA Earth Observatory website">Herring, David. What Are Phytoplankton. NASA Earth Observatory website">phytoplankton plays in nutrient dynamics. Since phytoplankton can respond rapidly to a change in nutrient availability in the water column, they may quickly utilize much of the nutrients from the land, making them unavailable to both turf and Wikipedia">Wikipedia">macroalgae, which smother corals. Figure 1 gives an overview of our project.

The red arrows indicate the nutrient fluxes, which we would like to understand. We look at nutrients coming into the system (large arrows on the left), and what happens when these nutrients (A Dictionary of Environment and Conservation. Chris Park. Oxford University Press, 2007. Oxford Reference Online

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">Phosphate) are within the system (circle in the middle). To understand this, we have been conducting several fieldtrips on the island of Curaçao, in the Southern Caribbean.

On Curaçao we are comparing two different research sites. ‘Buoy 0’ is a rather unhealthy site and ‘Playa kalki’ is used as a healthy reef (see figure 2). At both sites, we conduct our research from surface water to 30m depth and at different distances from the reef (see figure 3). We perform numerous experiments, including (1) nutrient concentrations in the water column, (2) phytoplankton composition using Adapted fromNOAA CORIS
 

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">chromatography is a technique that can separate a mixture of compounds and is used to identify, and quantify the individual parts of the mixture.

We are also performing experiments on (3) nutrient limitation of benthic communities and phytoplankton, (4) element ratio analysis, (5) nutrient uptake rate, (6) Adapted from A Dictionary of Environment and Conservation. Chris Park. Oxford University Press, 2007. Oxford Reference Online. Oxford University Press. & World Encyclopedia. Philip's, 2008. Oxford Reference Online. Oxford University Press.
 

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">nitrogen fixation by phytoplankton and turfalgae, (7) primary production experiments, and (8) we produce Hydrolab profiles to study The Canadian Oxford Dictionary. Katherine Barber. Oxford University Press 2004.
 

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">turbidity etc.

Our first fieldtrip was from September-December 2010 where we conducted preliminary research to understand the dynamics of nutrients in the water column (DIN & DIP), changes in phytoplankton composition on a reef, and we developed a new technique to measure nutrient limitation in micro- and macroalgae. We also did some preliminary studies to nutrient uptake rates of micro- and macroalgae. We continued in January 2011 and started our second fieldtrip and first ‘seasonal cycle’ (=dry season) where we conducted all experiments described above. Our results from the nutrient limitation studies are especially promising. We hope to present this study (‘Fast detection of nutrient limitation in micro-and macroalgae’) at the International Coral Reef Symposium (ICRS) in Australia in 2012.

Currently I am on my third fieldtrip (September-December 2011) which is also our second seasonal cycle (=rainy season). I took three students with me, Moriah Sevier (University of California Santa Cruz), Nienke ten Brinke (Wageningen University), and Philipp Kutter (University of Rostock) who are all conducting their own projects. Moriah is studying ammonium and phosphate uptake rates of macroalgae, corals, sponges, and phytoplankton. Our first results clearly show differences in uptake rates among these groups, which is important for the model we would like to create at the end of my PhD. This model will hopefully describe what will happen with nutrients when they enter a reef, show where do they go and whether they will be taken up by phytoplankton before they reach the smothering macro- and turfalgae. Nienke is conducting our nutrient limitation study as part of her MSc, where she uses the NIFT technique in conjunction with a Pulse Amplitude Modulation (PAM) fluorometer to detect nutrient limitation in macroalgae, turfalgae, benthic Oxford English Dictionary">Oxford English Dictionary">cyanobacteria, and phytoplankton.

What are NIFT and PAM? NIFT stands for Nutrient Induced A Dictionary of Environment and Conservation. Chris Park. Oxford University Press, 2007. Oxford Reference Online.
 

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">Fluorescence Transient experiment and it is a way to identify nutrient limitation using fluorescence of phytoplankton & cyanobacteria. PAM, pulse amplitude modulation fluorometer is a portable submersible fluorometer. Fluorometers that use the PAM technique work by rapidly sending brief pulses of light to a plant or other organism. A healthy organism responds to this light very quickly (within microseconds) by re-emitting some of the light at a longer wavelength.

Finally, Philipp is conducting a study on the primary production of micro- and macroalgae as part of his Diploma Thesis (MSc thesis). This study is part of a collaboration with another FORCE PhD student, Hannah Brocke, from the ZMT and MPI in Bremen, Germany.

During the coming months I will stay in Curaçao to hopefully finish up our nutrient limitation studies, because we want to have good data to present at the ICRS2012. If you would like to have more information about me or my project, feel free to contact me at j.denhaan1@uva.nl or  check my website: http://home.medewerker.uva.nl/j.denhaan1/

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Our Social Science Field Team in the Bay Islands,Honduras

During the months of June-August 2011, the FORCE social science field team travelled to Honduras to conduct field work in three coastal communities in the Bay Islands. The areas of focus included: social networks among reef stakeholders, governance structures and reef management, livelihoods and adaptation to change, and the economics of the reef fishing and dive tourism industries.

West End

 

 

 

 

 

The social science team arrived in West End, Roatan on 12th June 2011. Roatan is the largest of the Bay islands and is also the most developed. It does not take long for anyone to recognize the importance of the SCUBA diving industry to the West End community with over 12 dive shops located along a 1.5 km stretch. Many accredit this to the vibrant reefs within the Roatan Marine Park, with over 40 dive sites located within a few hundred metres from shore. This is one of the few sites in the Caribbean where large groupers and schools of snappers can still be observed in reasonable numbers on nearshore reefs.

            Snappers and groupers in the Roatan Marine Park, West End.

Reef Management in West End

Most people we talked to thought that the Marine Park is doing the best it can with the resources available, and overall is a positive organisation. However, several people expressed concern about illegal fishing in the Marine Park, and suggested that more resources are necessary for increased patrolling. The invasive lionfish was also another concern. Many people recognised that the Marine Park are trying to involve the community through education, awareness building and providing information, and people commented that the community is more aware now of the importance of protecting the reefs. However, some people also thought that there should be more local people involved in the Marine Park.   

East Harbour

On July 3rd, the team then departed Roatan on Vern’s Catamaran to head to the second island of Utila. East Harbour is the main town within Utila and is located in the south-eastern part of the island. Dive tourism is also very important to the Utilian economy with tourists arriving each day mostly by ferry from the mainland port of La Ceiba. A large majority of these tourists are back-packers who are attracted by low-cost dive certifications and cheap accommodations. Some dive operators boasted that Utila is one of the cheapest places in the world to get certified. Perhaps the most popular dive attraction on Utila are the whale sharks that can be observed around the island all year around but primarily between the months of February-April.

                                                              Local dive shop in East Harbour, Utila

At each site, the social science team holds a community meeting where we introduce ourselves to the community and discuss the major changes that have impacted both the reefs and the community within the last 50-60 years.
 

Advertising for the community meeting is sometimes a difficult undertaking however we were offered an opportunity to spread the word about the FORCE project and the community meeting on the island’s local TV station.
 

Livelihoods in East Harbour (Tourism Dependency)

 Tourists returning from a trip to Water Cay with Captain Jake

There was a feeling that the reefs should be better protected as Utila depends almost entirely on the dive industry. In terms of fishing, there is some commercial fishing, but most is in deep water or on offshore banks so direct dependence on the near shore reef is low. Tourism has provided opportunities for people to get involved in the dive industry, or work as boat captains running snorkelling and fishing trips for tourists. These jobs provide more money than fishing used to. However, some said there are few opportunities for young people, as the tourism industry is saturated, and there are few local dive instructors on the island. People were also concerned about the dependence on this one sector if the health of the reef was to decline in the future.

Utila Cays

 

After 2 ½ weeks in East Harbour, the team hopped on a boat to head to the Utila Cays, located off the southwestern tip of Utila. There are many small cays that make up the Utila Cays, with most of the inhabitants living on Upper Cay and Lower Cay (also called Pigeon Cay and Jewel Cay). The Utila Cays are much less developed than Utila which only recently acquired modern conveniences such as 24-hour electricity within the past 10-20 years. The community within the Utila Cays is very small and tight-knit and the main activity on the island is fishing. To introduce ourselves to the community, the FORCE social science team organised a movie night and showed a documentary, which highlights fishing in coastal communities around the world. This event had a tremendous turnout as almost all the residents of the community showed up for the event.

Fishing in the Utila Cays

Over 90 fishers were interviewed from the Bay Islands, including people who fish for food, for fun and to earn a living. Most were “local islanders”, as well as people from around the north coast of Honduras. Fishing plays an important role in the lives of many on the Bay Islands. In the Utila Cays, many of the fishers interviewed own wooden or fiberglass dories and fish with rods and reels or by hand. Fishers in the Utila Cays travel many miles from shore to fishing sites and shallow banks around the Bay Islands. In addition to trolling and bottom fishing for yellow-tail snapper, deep fishing for grouper and snapper species such as black-fin snapper, queen snapper and “yellow-eyes” is also very popular. Fishers spend about 9 hours line fishing and the average age of the fishers was 46 years. Fishers from the Utila Cays are very knowledgeable about the movement of fish and know how the “moons” and the seasons affect fish behaviour. For example, in the mutton snapper fishery the fishers know how storms trigger the arrival of these fish and so the community gets involved to make use of this opportunity. Diving for lobster and conch also appears to be a very important fishery and high prices are received for their sale. Many people have noticed a decline in the number and size of these animals and are concerned that it may get worse in the future.

                Yellowtail snapper

David Gill, CERMES, UWI

Photos: David Gill

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Juvenile coral abundance in Curacao shows great decline over recent 30-year period 

A recent study by one of the FORCE partners, Carmabi has shown that the number of "young" corals on coral reefs on Curacao has drastically decreased since researchers started looking at them in the early 1970's. By repeating an unique 1975 study, Carmabi researchers, for the first time, were able to quantify the changes that have occurred regarding the abundance of the young or juvenile corals that would normally grow to become the reefs of the future. According to the lead author, Dr. Mark Vermeij from Carmabi, the findings highlight several unexpected aspects of coral reef community dynamics: 1.) a decline of just over 50% in juvenile coral abundance and 2.) a shift in species that make-up the reef. Agaricia species and Helioseris cucullata,which were the most common juveniles in 1975, showed the largest decline in juvenile abundance. The coral Helioseris cucullata or Sun ray lettuce coral were nearly completely eradicated locally. In 2005, Porites astreoides provided the most colonies to the juvenile coral community. Unexpectedly, juveniles of NOAA CORIS

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">broadcast spawner species increased or remained the same.

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">recruitment, growth and survival) on a timescale meaningful to both ecology and conservation. While the over 50% decline in juvenile abundance observed between 1975 and 2005 can both be a cause and a consequence of the decline in adult coral cover on these reefs, it indicates that fundamental processes required for population maintenance and recovery are operating at lower rates than thirty years ago. It is important to have historical comparisons like the one described here because they show that taking only recent inventories of coral juveniles alone are not sufficient to understand the changes that have occurred on Caribbean reefs over many decades. The near-disappearance of once abundant species, such as Helioseris cucullata, in the relatively short time span of 30 years would have been missed if only recent surveys were considered.

Dr. Vermeij, notes, “The overall decline in juvenile coral abundance in Curaçao over a period of 30 years is representative of the profound changes that are taking place in the structure of juvenile coral communities region-wide. Reduced in numbers and subject to increasing stress, these juvenile populations face the heavy burden of serving as the next generation of corals on Caribbean reefs.”

The complete paper can be accessed at:

http://www.mdpi.com/1424-2818/3/3/296/pdf
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Shark Tales from Honduras: First bioceanic shark sanctuary in the world

There was much excitement in Honduras last month as the first bioceanic permanent shark sanctuary in the world was established in Honduran waters. The sanctuary includes the entire exclusive economic zone, encompassing 240,000 square kilometers (92,665 square miles) and extends across the waters of the Pacific and Caribbean coasts.

From 2010 the Honduras government had declared an indefinite moratorium on fishing, commerce or export of all shark species. Whilst there is currently only limited information on the extent of shark fishing in Honduras, it is estimated that up to 73 million sharks are killed globally every year, and that shark fisheries are unsustainable.¹ The Honduran government has been proactive in conserving sharks, realising that the long term benefits to marine ecosystems by protecting sharks and developing tourism potential outweigh the short term gains of the fishery.

Our Honduran project partner, Utila Centre for Marine Ecology (UCME) is working on quantifying the extent of shark exploitation in Honduras as well as developing management strategies that will help reduce the bi-catch of sharks by other fisheries, help to limit their illegal trade and identify ways to extend the conservation to neighbouring countries in the region. Steve Box, one of FORCE’s principal researchers and UCME director, shares his perspective on the occasion and some of the research they are conducting on sharks in the region.

“As part of the declaration event that was held on Roatán, we released two nurse sharks that had previously been kept in shallow pens for tourists. Working with a team of volunteers we had to catch them from the enclosure, transport them in a seawater pool on the back of a boat and then rendezvous with the president for him to help release them. The event was being watched by the ministers of tourism from Central America, along with another 80 dignitaries, from two glass bottom boats. Whilst explaining the importance of sharks to the president and techniques for photo identification, I was trying to avoid having my toes sucked by the 5ft nurse sharks (see photo below). The release itself was met with a resounding cheer from the onlookers as the freed sharks swam down to the coral reef below. What an amazing day..” 

“In other fun happenings from Honduras, I also got to go down in a submarine in the first attempt to tag an adult, sixgill shark at 2000ft below sea level. Very little is known about these deep water scavengers and the deep water off the north coast of Roatan provides a convenient place to study these slow moving sharks. After waiting in the cold and dark for three hours on the sea floor with bait tied to the front of the sub a 16ft shark finally made an appearance. Making slow turns in front of the submarine to find the bait, it came in front of the harpoon perfectly. The pilot fired the harpoon with the satellite tag attached, but whilst scoring a direct hit, the shark’s skin was so thick that the tag bounced right off. Oh, darn! Disappointingly you only get one shot, as you obviously can’t go outside to reset the harpoon. At least we still have the tag, and now have a better idea of how much force to put on the spear gun to get it through its hide. We were very cautious of the amount of power used in the first attempt as we did not want to traumatize it unnecessarily but now we know we are going to need to pack more power to penetrate such tough skin. We will be back down again with the sat tag once we can reliably get the tags to adhere. In the mean time the pilot will use simple identification tags so that he can start recording sightings of different individuals in the area as we build up new information on the populations of this species.”

“The experience was amazing though, to be in a little yellow submarine, (the deepest diving commercial submarine in the world) with a large shark only inches from you on the other side of the window. The Honduran president also went on a short dive, to 500ft, making him the first sitting president in the world since Roosevelt to go in a submarine.”

 

No doubt we will be hearing again from Steve and his shark adventures in Honduras.
¹ Maximiliano Bello, senior advisor to the Pew Environment Group in Latin America

Photos: Shark at top: Renata Ferrari Legoretta; Other two photos: Steve Box
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Grouper may help to control invasion of lionfish on coral reefs

Grouper may be able to limit the invasion of lionfish on Caribbean coral reefs, reports a study published on the 30th June in the online journal PLoS One. The lionfish (Pterois volitans) is naturally found in the Indian and Pacific Oceans. They are not native to the Caribbean and are believed to have been released from aquariums in the United States and eventually made their way to the Bahamas in 2004. Lionfish numbers have increased dramatically in the last few years and they have now invaded the entire Caribbean.

Although lionfish are among the most beautiful fish in the sea, they are voracious predators of small fish and conservationists are concerned about their impact on native fish populations.

 

One of our FORCE research teams from the University of Queensland (Australia) along with the American Museum of Natural History (New York) studied the invasion of lionfish in a remote stretch of coral reef in the Bahamas. The report’s lead author, Professor Peter Mumby, states, "In 2006 we did not encounter any lionfish but by 2010 they were at all of our 12 study sites. However, the number of lionfish was ten times lower in reefs with lots of large groupers". The team surveyed reefs inside and outside the Exuma Cays Land and Sea Park, which is one of the best marine reserves in the Caribbean, having been established in 1959. Prof Mumby continues, "With long-term protection from fishing, grouper numbers are among the highest in the Caribbean and we believe that groupers are eating enough lionfish to limit their invasion on these reefs".

Lionfish have high venomous spines to protect them from predators. Indeed, there are few known predators of lionfish so it is exciting to discover that Caribbean groupers are able to control their numbers. Previous studies have found lionfish in the stomachs of grouper.

This news is positive for conservation efforts but Prof Mumby adds a cautionary note, "Years of over-fishing means that densities of large grouper, like the Nassau grouper, are low throughout most of the Caribbean. If we want grouper to help us control the lionfish invasion we'll have to develop a taste for lionfish instead of grouper and drastically reduce the fishing of this species".

The manuscript can be viewed and downloaded for free at:
http://dx.plos.org/10.1371/journal.pone.0021510
Photos: Grouper (top left): Renata Ferrari Legoretta & Lionfish (middle right): Chris Roelfsema

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Coral physiology experiments in Puerto Morelos, Mexico

Hello, my name is Tim and I’m a PhD student at the Universidad Nacional Autónoma de Mexico (UNAM). Originally from Germany I relocated my life in 2010 to Mexico, to join the FORCE team at the Reef System Unit of the UNAM, located in the town of Puerto Morelos, Yucatan Peninsula, right at the northern tip of the Mesoamerican Reef System. As mentioned in earlier blog entries, our task within the FORCE is to provide experimental data for the team(s) involved in modelling the responses of corals to changes in temperature and aragonite NOAA Coral Reef Watch

">NOAA Coral Reef Watch

">saturation state. To best accomplish this task we have been very busy redesigning and extending our Oxford English Dictionary">Oxford English Dictionary">mesocosm facilities to accommodate experiments under different pH and temperature conditions.                                                                                                   

After a first test with two related coral species (Montastraea annularis, M. faveolata), with similar The Oxford Dictionary of English (revised edition). Ed. Catherine Soanes and Angus Stevenson. Oxford University Press, 2005.
 

">The Oxford Dictionary of English (revised edition). Ed. Catherine Soanes and Angus Stevenson. Oxford University Press, 2005.
 

">morphology and appearance, it was interesting to see that these species showed significant differences in pigmentation and cell number under similar light conditions. We then further analysed the different A Dictionary of Genetics. Robert C. King, William D. Stansfield and Pamela K. Mulligan. Oxford University Press, 2007. Oxford Reference Online. Oxford University Press. Queensland University.1 June 2010.">A Dictionary of Genetics. Robert C. King, William D. Stansfield and Pamela K. Mulligan. Oxford University Press, 2007. Oxford Reference Online. Oxford University Press. Queensland University.1 June 2010.">symbiont types harboured in each coral and could see significant differences between species in the contribution per symbiotic cell towards photosynthesis and thus energy for the coral. Based on these preliminary results we didn’t hesitate to start the second phase of our experiments, which increased the species number in our experimental approach to four (M. annularis, M. faveolata, M cavernosa and Diploria strigosa), comparing their response to three different temperatures and light conditions. Within this setup we were able to observe the coral and symbiont’s performance over a period of one month before, during and after a stress-period of 10 days.

Right now we have finished the winter experimental phase and are very busy analysing the data generated. All I can say for now is that some of our experiments have produced interesting results describing the synergistic effect between light and thermal stress in corals acclimated to the winter conditions. We found significant interspecific differences among the four species in handling light in excess and in their sensitivity to increasing seawater temperatures. Next up, we will repeat the same experiment in summer. Comparison between both responses, will give us a deeper insight into the effect of thermal stress on coral physiology and the impact of climate change on the main coral builders in the Caribbean.

                           

Besides conducting experiments in our mesocosm facilities with corals collected from the reef in our back yard, we plan to extend coral collection to various sides in the Caribbean. This will enable us to compare corals acclimated over a longer timespan to different factors, such as temperature, water quality, and aragonite saturation state.

More results can be expected soon and we are all excited to see how it continues from here on. So come back and visit the blog for more updates on our work.
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The Old Fishermen, the Sea and Me

I first saw him sitting under the coconut tree, fishing rod in hand and a small bucket precariously balanced on the sand beside him, probably containing a few small chubs. I wondered how old he was, realizing he would be an ideal person to interview; I was certain he could provide a historical perspective on the changes on the reef. I approached him unhurriedly so as not to intrude on his vacant stare out to sea. He turned and looked up at me, offered a slight bow of the head which accompanied a mostly toothless smile and said “Good afta- noon young maam.” I returned his smile, introduced myself and asked him if I could sit and chat with him for a moment. He nodded guardedly and told me his name was “Truman.” I sat beside him on the sand. And so my pre-determined “questionnaire” began to be filled out.

At some point, I can’t say when it actually began, I realized the knowledge of this man could never be captured on the paper that I held so protectively in my hands. I looked at his weathered face and regarded the lines etched into his dark skin. Each line represented a decade of stories, adventures on the sea, stories that could never be summed up in a PhD or journal article. I remember I put my clipboard aside and decided not to just hear his responses to my questions, but rather, to start listening. I listened with my ears, my mind and heart to what he was telling me.

As I did this, I realized the value of the person I was sitting in front of. He told me stories of his boyhood, growing up on the same beach he now comes to as an old man. He explained how things were then, and how they had changed; his facial expressions changed with each story he shared. He told me the adventures of his invincible youth, his life adventures - told me proudly of his travels on ships, picking apples in North America and the secret desire he had during that time… to return to the same community, the same beach, the same reef. Fishing is more than his livelihood, more than his daily sustenance; it’s in his blood. Away from it, he craved it and did not feel the same without it….it defines him. He explained how he presently watches with a heavy heart the way the Government is allowing people, both foreigners and locals to destroy the very thing that sustains him. His voice cracked and in deeply set eyes, amidst the wrinkles that surrounded them, a tear. I choked and my heart broke: one story, one voice. Could it be heard through the data I was there to collect? Could that tear be collected and represented? We chatted for a while longer, and with the advancing evening, we parted ways, with my hopes of seeing him again.

I packed my things up and decided on a sunset swim. The only thing I knew would help me escape the tragedy of destruction of the sea as told to me by a man who I considered a living witness to what I merely study. I noticed how quiet the beach was. But the serenity did not bar the reality I had to acknowledge, the responsibility to this man and this community, that the data I collected did not get lost in translation, did not become numbers on a few sheets of paper, but would remain real life.

I dove into the warm water, swam alongside two turtles who regarded me like I didn’t belong, yet they willingly continued to share their space with me, for which I was grateful. By the time I turned back for shore, a few old fishermen had gathered on the beach. A few feet up from the gentle surf they had lit a fire in the rim of an old tire. They were roasting something that smelled so good. My mouth watered, and my stomach growled in response, reminding me that I had not yet eaten. The men stood at the water’s edge, dipping something into the water and then eating it…dipping and eating, dipping and eating. One by one, like a dance, they would make their way up to the fire, retrieve something and then make their way back into the warm surf, to start dipping and eating again.

I staggered out of the water and inquisitively asked one old fisherman, “What is that? What are you doing?” He contemplated me with a look almost identical in expression to the turtles, the who-are-you and what-are-you-doing-here kind, and then responded in two abrupt words: “flying fish”. I curiously and probably annoyingly asked him if I could try a bit. As with my old friend under the tree, this man’s skin was aged by the sun and sea, and full of stories to be told. For a split second he seemed to evaluate me, raising an eyebrow at my request, then perhaps realizing I was harmless, willingly shared a piece of his flying fish with me. It was good! I realized the men all stood in silence. If any of them minded my presence, I could not tell. No one really spoke as they dipped their fish and ate, dipped and ate. They stood in silence along the shore. The moment I felt like an outsider was fleeting. For just as I began thinking I didn’t belong, not knowing how to participate in their ritual, one of the old guys offered me my very own, fresh out the tire-rim-fire, roasted flying fish! Just like the rest of old men, I follow the code of silence and joined their dance peeling, rinsing and contentedly eating the fresh fish. It tasted even better than the first bite. I ate it S L O W L Y as if partaking in some Holy Sacrament.

It’s amazing... that in swimming with the turtles in silence and standing alongside these old men in silence... everything fell into place... as if I had suddenly attained some understanding of the lives of the fishermen. All evening I had tapped into some divinity of nature, where by doing so, she granted me insight into a world I cannot understand without truly humbling myself and embracing the stories of the old fishermen. That understanding and sincere desire to know more and learn more from these people, gave my soul a gentle jolt of peace - a nirvana of sorts.

I realized that I may not have been able to capture that evening in my data. It may not be represented in my PhD, but I valued it. I recognized the importance of valuing every interview that I still have to do. As with my old friend, Truman, I became conscious that, ”value has a value only if its value is valued”. And for that, I valued my time with Truman (and the silent fishermen) as one of the valuable moments of my life. I felt…blessed.

Rachel Allen, CERMES, UWI
Photo Renata Goodridge

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Benthic cyanobacterial mats – A new threat for coral reefs?

Hello there, my name is Hannah Brocke. I am, along with Gaëlle Quéré, in the first year of my PhD with FORCE and also a student of Dr. Maggy Nugues at the Leibniz Center for Marine Tropical Ecology in Bremen. My project operates in close cooperation with the Max Planck Institute for Marine Microbiology. During the last years, dense mats of benthic cyanobacteria have become more prevalent on coral reefs. Although cyanobacteria have always been a part of the ecosystem, the proliferation of these mats has been associated with widespread signs of reef degradation. My PhD explores the causes and dynamic of cyanobacterial mats and their consequences for the coral reef ecosystem.

My first field trip began in September 2010. For a first impression of what is going on along the leeward coast of Curacao, we conducted a rapid survey at 61 sites. During the field trip, environmental parameters (e.g. inorganic nutrients) of four low and four high abundance sites of benthic cyanobacterial mats were monitored. To study the diversity and abundance of benthic cyanobacterial mats, a detailed survey was conducted at two cyano dominated and two reference sites. Benthic cyanobacteria were photographed and sampled across a vertical depth gradient for morphology and genetic analyses (photo below).

                 

Bastian Piltz (pictured above with me), a master student, and Nicole Herz (right), a bachelor student, are currently working on the samples and writing their theses about this topic. On one cyano dominated site, a weekly monitoring program was started with 40 permanent quadrates 2m x 2m to study population dynamics (e.g. patch sizes, distribution) (left photo, below). In collaboration with another FORCE PhD, Joost den Haan, a small nutrient starvation and recovery experiment showed that probably phosphorus followed by iron are the limiting factors for the growth of benthic cyanobacteria. Also N-Fixation and production rates of the most abundant species were measured in 24 hour cycles using isotopes and Acetylene –Ethylene incubations (right photo, below). These experiments are also part of Bastian Piltz’s thesis.

   

First results show that benthic cyanobacterial mats are highly dynamic in space and time and are dominated by non-Adapted from Merriam Webster online 2011
 

">Adapted from Merriam Webster online 2011
 

">heterocystous cyanobacteria. The most abundant mats exhibit substantial nitrogen fixation rates. The limiting factors (phosphorus and iron) suggest sediments as a key factor triggering the blooms. To investigate this, work with microsensors (profiler) are planned for the third field trip.

Currently, I am on my second field trip on Curacao and happy to be back in the warmth ;-) The focus of this trip is to investigate the advantage benthic cyanobacteria have compared to other benthic organisms in the ecosystem. Do they have a competitive advantage in high nutrient water? How is their survival and recovery affected by nutrient limitation? Are there seasonal changes in their spatial and temporal dynamic?
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A risky future for reefs?

A recently released report called Reefs at Risk Revisited, produced by the World Resources Institute, says that more than 75 percent of reefs around the world are under immediate threat from either direct or indirect impacts from human activities.

This report, a global collaboration of 25 research, conservation and educational organizations is an update of a similar report released in 1998. This latest report includes maps that are 64 times more detailed than in the earlier report.

Like the original Reefs at Risk, this study evaluates threats to coral reefs from a wide range of human activities. Overfishing, farm runoff, sewage discharge and industrial pollution are also among the top offenders. For the first time, however, it also includes an assessment of climate-related threats to reefs. Warming sea temperatures and rising carbon dioxide lead to mass coral bleaching and death. In addition, Reefs at Risk Revisited includes a global assessment of the vulnerability of nations and territories to coral reef degradation. This assessment is based on their dependence on coral reefs and their ability to adapt to any changes. In the Atlantic region about 43 million people live on the coast within 19 miles of a reef. Many live in heavily populated small island nations.

According to the findings for the Atlantic region, more than 75 percent of the reefs in the Caribbean are considered threatened, with more than 30 percent at high and very high risk. “These local threats include (coastal development, marine-based pollution and damage, overfishing, or watershed-based pollution), Overfishing is rated as the most widespread threat, affecting almost 70 percent of reefs, but the reality may be even worse, with the only healthy reef fish populations being recorded from a small number of well-managed, no-take Marine Protected Areas (MPAs). “

There is strong evidence that coral diseases are more frequent after coral bleaching events and that reefs subject to local human stresses such as pollution, are also more at risk of disease. Climate-related threats are projected to push the proportion of reefs at risk to 90 percent in 2030, and up to 100 percent by 2050, with the majority of reefs at high, very high, or critical levels.

In terms of reef protection, the Atlantic region has 631 MPAs covering about 30 percent of the region’s reefs. They were able to assess the effectiveness of about half of these, of which, only 6 percent by area (286 sq miles) were classified as fully effective. “These very low effectiveness estimates reflect the immense challenges of establishing effective conservation when the pressures are so intense, management is costly, and full community engagement can be difficult to achieve.”

For more information and to download the report go to http://www.wri.org/publication/reefs-at-risk-revisited

Burke, L, Reytar, K, Spalding, M, Perry, A (2011) Reefs at Risk Revisited, World Resources Institute, Washington
Oko, Michael, (2011) Press Release:75% of World’s Coral Reefs Currently Under Threat, New Analysis Finds, World Resources Institute, Washington
Photo: Steve Newman

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Reef well-being : diseases in crustose coralline algae

My name is Gaëlle and I am a PhD candidate with Dr. Maggy Nugues at the Leibniz Center for Marine Tropical Ecology in Bremen, Germany. My PhD project will focus on the diseases affecting a particular group of inhabitants of the reefs, the red algae called crustose coralline algae or CCA. 

In the last two decades, disease outbreaks have played an important role in the loss of coral cover and the deterioration of Caribbean reefs. Disease are not only responsible for tissue loss, they also lead to changes in reproduction rates, growth rates, community structure, species diversity and abundance of reef-associated organisms.

CCA are plants that deposit a particularly hard and geologically resistant form of calcium carbonate. They are thus the principal cementing agent that maintains the structural integrity and resilience of the outer reef. The second key functional role of CCA is to act as settlement cues for coral larvae. Indeed studies have showed that induction of larval settlement and metamorphosis of many sessile organisms depend on the presence of CCA and their associated bacteria films. However, CCA may also employ physical and biological anti-settlement defense strategies that vary greatly in effectiveness. Due to these two critical roles, CCA may be considered as a key functional group in coral reef ecosystems.

Among the areas of distribution of coral reefs, the Caribbean is viewed as a disease hot spot due to a fast emergence of new diseases associated with reef organisms. I am working on Curacao where two different diseases have been observed: the Coralline White Band Syndrome (CWBS) [both photos] and the “Coralline White Patch”

CWBS is characterized by a loss of tissue leaving behind a sharp clean white band where the dead coralline thallus is exposed. In the Coralline White Patch, the disease usually appears in the center of the CCA and draws a white patch [photos below].

 

Despite the fundamental role of CCA in coral reef ecology and despite the fact that CCA are among the most abundant marine organisms to live on hard substratum within the photic zone, little is known about their ecology at the species level and more particularly about their pathologies. The global objective of my work is then to investigate the ecology and driving factors of CCA diseases and the effects on reef recovery processes using an integrated approach that includes a combination of field and laboratory methods from multiple disciplines. I have undertaken training with Dr. Bob Steneck at the University of Maine, USA in identifying CCA under microscope.

In the field, Phillip Kutter, a volunteer [photo at left] and I take a sample of each CCA we find with a hammer and a chisel and dry it for a few days in the oven in order to identify it. I take photo evidence of the progress of a lesion on a CCA. That involves taking photos regularly at different intervals. I also measure various environmental parameters such as temperature and light levels, current speeds, pH and nutrients.

These surveys and samples should help to provide insights into the occurrence and severity of the diseases according to the species of CCA it affects.

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Coral-excavating sponges: what are they feeding on?

Hi, my name is Benjamin Mueller and I am a PhD student working for the project partner, the Royal Netherlands Institute for Sea Research (NIOZ) in the Netherlands. Our role in the project is to find out whether coral-excavating sponges are feeding on dissolved organic matter (DOM).

Algae and corals release organic matter in the form of particles (particulate organic matter = POM) or dissolved (DOM) in the water column. Sponges in general are considered to be filter feeders, pumping water through their aquiferous system and clearing it from small particles. Recent research shows that the diet of some cavity sponges and open reef sponges consists to up to 90% of DOM. We are focusing on the role of coral-excavating sponges. Those sponges are able to invade dead and live corals. They are able to make excavations in the limestone to create a shelter for themselves. While doing this, they are killing the coral they are living in and they also weaken the structure of the reef framework.

During my first field trip we were focusing on the production of DOM by algae and corals. My supervisor Dr. Fleur C. van Duyl and I flew to Curaçao where we stayed at the research station of another project partner, the CARMABI Foundation. To identify possible sources of DOM on coral reefs we visited 9 selected sites along the south coast of Curaçao. At each site we took water samples with 100 mL syringes from the surface of two dominant coral species, two dominant macroalgal species and Adapted from NOAA CORIS
 

">Adapted from NOAA CORIS
 

">turf algae. As a reference we also took a sample from the bare sediment and the surface water at 5 m depth. The collected samples had to be transported to the research station as quickly as possible where they were processed and prepared for further analysis at the NIOZ in the Netherlands.

We also collected dominant algal and coral species in the house reef of CARMABI and held them in the aquarium building at the research station. After one day of acclimation time we put them in 1 L incubation chambers and followed the DOM concentration over 5 h. With those experiments we tried to determine the release rates of DOM of different corals and algae over time.

After finishing those two experiments I had the unique opportunity to attend a course on the Taxonomy, Systematic and Ecology of Caribbean Sponges at the Smithsonian Tropical Research Institute (STRI) at Bocas del Toro, Panama. In an intensive two weeks course I was able to extend my knowledge on Caribbean sponges in general and coral-excavating sponges in particular. This will help me in the future when the real sponge work starts.

After three months in the tropics I finally flew back to the Netherlands where I had to analyze the data gathered on Curaçao,and in September Dr. Fleur van Duyl and I were already able to present some of the preliminary findings of my first field trip at the VIII World Sponge Conference in Girona, Spain.
 

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Best place to be: Location important to coral reefs’ vulnerability to rising sea temperatures

A paper published last week in the scientific journal Ecology Letters, led by the FORCE co-ordinator, Professor Peter Mumby at the University of Exeter and the University of Queensland, shows new research which highlights areas where corals can better withstand rising sea temperatures which is a cause of stress to coral reefs.

From our other entries (see stories further below) we know that a rise in sea temperature causes stress to corals and can lead to coral bleaching, where corals lose their symbiotic algae, the zooxanthellae that help them grow, resulting in large areas of dead coral.

Sea surface temperature rises of as little as 1°C can cause bleaching and the warming sea temperatures could cause coral to die in large numbers. The destruction of coral reef ecosystems will expose people in coastal areas to flooding, coastal erosion and for those dependent on reef-based fisheries and tourism, the loss of food and income.

Dr. Susanna Enríquez & Dr. Roberto Iglesias-Prieto, our FORCE partners from Universidad Nacional Autónoma de México and collaborators, Dr. Claire Paris from Rosenstiel School of Marine & Atmospheric Science at the University of Miami, and Dr. Mark Eakin from NOAA, along with scientists from Australia and the UK mapped coral thermal stress across the Bahamas and found that sea temperatures, caused less stress to reefs in certain areas.

The researchers designed marine reserves best-suited to four possible scenarios of how coral would respond to further sea temperature rises. In each hypothetical scenario, 15 percent of the locations in the Bahamas were consistently selected. Professor Mumby says that while the research complicates current understanding of marine reserve design, the findings can help make the best use of the limited resources available for coral reef conservation.

Map shows areas of thermal stress for  reefs in the Bahamas.

 

 

 

 

 

 

 

“Designing marine reserves for the long-term is more difficult than we thought”, Prof. Mumby says. “The responses of coral to the impacts of climate change are relatively unknown at this stage. Yet the good news is that some geographic locations were consistently selected in the computer generated scenarios, regardless of how corals might adapt to warmer temperatures.

“These areas are great contenders for early conservation no matter what the future holds”. He adds that, “The research found good locations for protecting corals and we are providing this information to conservation partners in the Bahamas to help them in their efforts to work with local communities and establish new reserves.”

Prof. Mumby says the response of coral to climate change is an ongoing focus for scientists and conservation advice will be updated regularly to reflect new research findings.

Photo: Bleached Montastraea coral; Credit, H Bahena ECOSUR

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2005 Coral Bleaching in the Caribbean – “Worst on Record”

A paper published last week in the academic journal PLoS ONE by one of our collaborators, provides the results of the mass 2005 coral bleaching the Caribbean. Dr. Mark Eakin and several other scientists from 22 countries conducted extensive surveys into the 2005 bleaching event.

The satellite based tools that NOAA uses in its Coral Reef Watch monitoring programme was used to guide the selection of sites for field studies which were conducted across the Caribbean from June to October 2005. The field surveys of corals that bleached and those that died as a result of bleaching was one of the most detailed and extensive.

Coral bleaching happens when corals are stressed and they expel their symbiotic algae, zooxanthellae. As you’ll see in the other story (below) zooxanthellae are vital to a coral’s life. Hence, if the stress is prolonged or very severe it can result in the coral’s death.

“Heat stress during the 2005 event exceeded any observed in the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in at least 150 years,” said C. Mark Eakin, Ph.D, coordinator of NOAA’s Coral Reef Watch Program. “This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems, and events like this are likely to become more common as the climate warms.”

He also added, “A few key things this survey showed were that several species of coral and places reported bleaching for the first time.” For example there was, the first documented mass bleaching at the Flower Garden Banks National Marine Sanctuary in the Gulf of Mexico, the first known bleaching of any kind in Saba in the eastern Caribbean and the first reported mass bleaching in Virgin Islands National Park, also in the eastern Caribbean the bleaching of Acropora palmata, a threatened species.¹

In one of our earlier stories (see Coral Bleaching Watch, further below), we noted that NOAA’s monitoring programme had predicted a bleaching event this year in the Caribbean. In some cases the higher temperatures have caused further damage to reefs already hit hard during the 2005 event, but new locations have also been impacted. For example the Los Roques Archipelago in Venezuela has experienced a massive bleaching this year whilst in 2005 they were not so affected.

The study concluded that: thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.¹

¹ Eakin CM, Morgan JA, Heron SF, Smith TB, Liu G, et al. (2010) Caribbean Corals in Crisis: Record Thermal Stress, Bleaching, and Mortality in 2005. PLoS ONE 5(11): e13969. doi:10.1371/journal.pone.0013969

Photo:Bleached Montastraea annularis, Maggy Nugues

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Cosy cohabitation – the role and genetics of zooxanthellae in corals

Hello, my name is Emma and I’m a PhD candidate under the supervision of Prof. Peter Mumby and Dr. Jaime Stevens at the University of Exeter. As part of the FORCE project, I’m focusing on a particular stony coral species, Montastraea annularis, which plays an important role in the construction of Caribbean reefs. Reef building corals like Montastraea produce calcium carbonate (limestone) skeletons, helping to build up a three-dimensional reef framework over time. One component of my PhD project involves modelling the accumulation and breakdown of this calcium carbonate framework, specifically looking at the balance between biological and abiotic or physical processes that build up and break down reefs. But the real key to the success of the reef building corals is the relationship between corals and their algal endosymbionts. It’s these endosymbionts we’re setting out to discover more about for FORCE!

What is an endosymbiont? Let’s look at symbiosis: an important part of life on the reef

Endosymbiont refers to a partner in a symbiotic relationship that penetrates the tissues or cells of the other partner. Corals – and many other reef invertebrates - contain high densities of microscopic single-celled algae, known as zooxanthellae, which reside within the coral’s tissues. Although these algal endosymbionts are very small, they’re extremely abundant: with more than 10,000,000,000 zooxanthellae found in every m²; they’re an important part of the reef¹! The algae have a symbiotic relationship with their coral host: corals rely on the products produced by the algae during photosynthesis (such as glucose) for nutrition; while the algae utilize waste products (ammonium and carbon dioxide) generated by coral respiration. The algae may also benefit from the protection they gain from living within the coral structure. As well as providing up to 60-95% of coral’s energy requirements², zooxanthellae benefit the coral in many other ways, including helping corals build up skeleton and protecting coral against sun damage – by giving the coral’s their colours.

The strong relationship between corals and their zooxanthellae have allowed corals to flourish in clear Caribbean tropical waters where little nutrients are available, and where few other animals could survive without support. In turn, the reef structures they build create habitat for more animals and plants leading to reefs becoming some of the most highly biodiverse ecosystems on the planet.

Zooxanthellae in a changing environment

But the symbiosis faces an unprecedented threat in terms of thermal stress. Like many plants, zooxanthellae tend to be adapted to specific temperature and light regimes, and don’t like conditions to be too hot, too cold, too sunny or too dark! Prolonged exposure to elevated sea surface temperatures or to high irradiance can cause stress. Zooxanthellae can lose important chlorophyll pigments, be expelled from the coral tissues or even die as a result of this stress. When zooxanthellae are lost from coral tissues (due to death or expulsion), the coral appears whitened, which is why the phenomena is known as ‘coral bleaching’.

Without their zooxanthellae, corals don’t get enough nutrition, which leads to the reef stops growing and can become covered in algae or even start to be disintegrated by bioeroding organisms (such as worms, sponges) that burrow into dead calcium carbonate framework. If the coral survives the stress period, zooxanthellae may return, but it can take weeks before they return to their normal densities, and the corals get their colours back. As well as temperature and irradiance changes, sedimentation and changes in water chemistry can also cause corals to bleach. Our NOAA partners in the FORCE project monitor for bleaching ‘hot spots’: areas where sea surface temperatures rise by 1ºC or more and bleaching is likely to occur. This October, NOAA satellites have shown high risk of bleaching throughout the Caribbean, so everyone’s been on high alert.

Zooxanthellae diversity and their role in reef resilience

In the 1960’s scientists thought all zooxanthellae belonged to a single species, which they named Symbiodinium microadriaticum³. This was because under the microscope, the external morphology, or form, of different zooxanthellae cells are extremely difficult to tell apart. The development of molecular genetic techniques in the 1980’s and ‘90’s have meant that scientists have been able to distinguish between different types of zooxanthellae that have similar appearances, based on their genetic make-up⁴. Thanks to these techniques, we now know that a huge diversity of different zooxanthellae species exist, although they are still in the complicated process of being categorized!

To simplify things, scientists have grouped zooxanthellae that are genetically similar to each other into taxonomic or classification groups called clades, based on differences observed between certain regions of their genomes or genetic material. There are currently nine clades that have been discovered, named A-I.

In some regions of the Caribbean our study coral, Montastraea annularis, is known to host clades A, B, C and E. We know some corals only contain one clade, while others may harbour a mix of several types. The combination of clades an individual coral contains can also change over time, as corals ‘shuffle’ or ‘switch’ the zooxanthellae within their tissues – sometimes in response to environmental change. Scientists have also observed that zooxanthellae belonging to different clades appear to have slightly different tolerances and properties: zooxanthellae belonging to clades E and C, for example, tend to thrive in corals living in shaded or cool water populations, while clade D zooxanthellae exhibit a higher thermal tolerance than other clades, meaning that they’re more resistant to bleaching⁵.

Assessing the diversity of zooxanthellae within the Caribbean is an important step in understanding reef resilience to environmental change. The type of symbiont residing within a coral can influence the growth rate of corals⁶, their ability to cope with high levels of irradiance and thermal stress⁷. Small chips (the size of a fingernail) of Montastraea annularis coral have been collected from more than 30 sites across the Caribbean by scientists at the University of Exeter⁸. This has provided an exciting dataset – perhaps the biggest collection of coral samples - which FORCE has been allowed access to, giving me the exciting opportunity to investigate their zooxanthellae! My role in the FORCE project is to use genetic techniques to explore the diversity of zooxanthellae within these coral samples to try and answer some important questions, such as: Which zooxanthellae clades does Montastraea annularis corals contain? Does symbiont diversity vary regionally across the Caribbean? Are environmental factors or relatedness of corals more important in explaining diversity?

My role in the project

My aim is to assess Symbiodinium diversity within Montastraea annularis, creating a map of types across the Caribbean which might help us understand differences in clades. Hopefully this can be later linked in with projects run by the team at Universidad Nacional Autonoma de Mexico, who are looking at corals from different regions of aragonite saturation state.

As a field based ecologist, my first challenge was to get to grips with some of the genetic lab techniques I was going to be using! A week of training at the School of Genetics for Marine Conservation in Chioggia, Italy, helped me practise some of the techniques I’ll be using in the laboratory, play with different types of genetic analysis software and plan my lab protocol. We’ve decided to focus our efforts on a certain region of zooxanthellae genome, called the ITS2 region, which has proved useful for distinguishing between different clades in previous studies. The next step was to collect some more samples to complement our freezerload!

Back in the lab, we’ve carefully extracted the DNA from some of our coral-algal samples. We chose primers, or strands of biological molecules used in DNA replication, that specifically target the ITS2 region of the zooxanthellae genome (to make things difficult, the coral genome also has this region!). The primers, which are used to make copies, help us to isolate this region from the mix of DNA, and increase the number of copies so we can analyse ourdifferent samples and assign them to clades. Watch this space for results…

If you are interested in this part of the project and want to know more - or have any suggestions for me - please drop me an email at: e.kennedy@exeter.ac.uk!

 References:

1. Baker, A. C. (2003). "Flexibility and specificity in coral-algal symbiosis: Diversity, ecology, and biogeography of Symbiodinium." Annual Review of Ecology Evolution and Systematics 34: 661-689.
2. Muscatine L, Falkowski PG, Porter JW, Dubinsky Z (1984) Fate of photosynthetic fixed carbon in light and shade-adapted colonies of the symbiotic coral Stylophora pistiIlata. Proc R Soc London Ser B 222:181-202
3. Freudenthal, H. D. (1962). "Symbiodinium gen. nov. and Symbiodinium microadriaticum sp. nov., a zooxanthella: taxonomy, life cycle and morphology." Journal of Protozoology 9(1): 45-&.
4. Rowan, R. and D. A. Powers (1991a). "A molecular genetic classification of zooxanthellae and the evolution of animal-algal symbioses." Science 251(4999): 1348-1351.
5. Berkelmans, R. and M. J. H. van Oppen (2006). "The role of zooxanthellae in the thermal tolerance of corals: a 'nugget of hope' for coral reefs in an era of climate change." Proceedings of the Royal Society B-Biological Sciences 273(1599): 2305-2312.
6. Little, A. F., M. J. H. van Oppen, et al. (2004). "Flexibility in algal endosymbioses shapes growth in reef corals." Science 304(5676): 1492-1494.
7. Baker, A. C. (2001). "Reef corals bleach to survive change." Nature 411: 765-766.
8. Foster, N. L. (2007). Population dynamics of the dominant Caribbean reef-building coral, Montastraea annularis. Schoolof Biosciences. Devon, UK, University of Exeter: 275.

Photos: Photo 1: Montastraea annularis  Credit: H. Bahena ECOSUR Photos 2 : Credit Mark Vermeij Photo 3: At a study site. Credit Phil Shears Photo 4: Samples Credit Emma Kennedy Photo 5: Emma at work. Credit Phil Shears Photo 6: Summer school, training in lab techniques. Credit: University of Padua Photo 7: Gel electrophoresis - testing validity of samples at the summer school in Italy. Credit: Emma Kennedy ______________________________________________________________________

63rd Gulf and Caribbean Fisheries Institute (GCFI) Meeting:

Reflections from UCME (Utila Centre for Marine Ecology)

The sixty-third annual Gulf and Caribbean Fisheries Institute Meeting took place from the 1st – 5th November 2010, in San Juan, Puerto Rico. The meeting covered a range of topics, from coral reef management for sustainable fisheries to the lionfish invasion of the Caribbean. Some of the FORCE project members were in attendance and the diverse themes of the conference made a great forum for members of FORCE project to present, discuss and promote the current and future work. 

One of the highlights of the conference occurred beyond the confines of the lecture hall. Steve (the big one) and I (Steve C, the little one) took the opportunity to go to three artisanal fishing cooperatives within San Juan. Each of the three communities was very different and it was great to be able to talk and ask questions to the fishermen, and compare their views with the situation in Honduras. The fishermen in all of the communities were very friendly and obliging, especially as over 25 scientists descended upon them all at the same time, with different questions about their fishery, tackle, gears and boats, being shot at them every 2 seconds.

As Steve and I rummaged through freezers and cold rooms looking at the catch, keeping up a string of banter with the fishers, we discovered a rather unexpected box of fish. It wasn’t a bag of frozen parrotfish or a set of unhappy looking grunts (although both were there) but rather a long, silvery fish with mottled grey and black scales. We hadn’t found a box full of barracuda, but rather a load of Atlantic salmon. Apparently the entrepreneurial fishers have taken to importing farmed salmon from Iceland (via the U.S.) for local restaurants, since they have the store rooms to be able to keep them cold. Nothing could have bought into focus the current crisis in local fisheries more than the beady eyes of those salmon peering out from their polystyrene boxes. 

So amidst stories of how to net parrotfish (use a big net at sunset) and what the best bait for traps is (depends on what you want to catch), the day was made even more memorable by an exceptional lunch put on by the last fishing community we visited. Feeling slightly like a hobbit (having already been fed on the bus en route) this second lunch was a wonderful plateful of local fare: yellow rice with chorizo (Spanish sausage), beans with pork, delicious slices of breaded Dorado (also known as Mahi-Mahi or Dolphinfish), and a little salad to round it off. Needless to say we were the first in line! 

Throughout the week FORCE members used the opportunity to meet up, many for the first time as not all had been able to make it to the Barbados kick-off meeting, and discussed various aspects of the project sipping a horrendously over priced beer ($9). It was great to finally meet some of the members that will be coming to Honduras next year to conduct fieldwork and discuss the exact requirements of each of the different researchers. We also managed to discuss aspects of the FORCE project with other researchers in the region and to develop future collaborations to aid in the success of the project. All in all a week well spent and now we are back in Honduras defrosting from the effects of the ubiquitous and overzealous Puerto Rican air-conditioning we won’t miss and hunting for recipes to make the delicious mofongo, that we will. 
                                                                        At one of the fishing communities

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Discovery along the way: Upwelling areas as refuges for coral reefs in a warming ocean?

As part of the FORCE project, we at the Marine Spatial Ecology Lab at the University of Exeter (UK) are describing the physical environments in the Caribbean using multiple data sources. Using various sources of data generally involves a lot of time on the computer!

As often happens when doing research, we discovered some very interesting things along the way. While analysing sea surface temperature patterns in the Caribbean, we realized that some cool upwelling areas weren’t showing lower thermal stress than neighbouring, non-upwelling ones. This caught our attention. Upwelling areas, where warm, surface water is replaced by cold water brought up from the subsurface, have been heralded for a long time as possible refuges from bleaching so our observations made us wonder: should we really generalize? Are upwelling areas always refuges for corals in a warming ocean?

To answer this question, we used satellite temperature data to analyse the degree to which upwelling reduces the thermal or heat stress experienced by corals in four major upwelling systems: Colombia in the southern Caribbean, Panama in the eastern tropical Pacific, Oman in the Arabian Sea and Madagascar in the Indian Ocean. Upwelling was only able to offer protection from thermal stress in Colombia and Oman, indicating that upwelling areas do not guarantee sanctuary for coral reefs in a warming ocean.

For more information, you can check out the research article paper entitled, Upwelling areas do not guarantee refuge for coral reefs in a warming ocean by Iliana Chollett, Peter J Mumby (University of Exeter), and Jorge Cortés (Universidad de Costa Rica) which will soon be out in the journal Marine Ecology Progress Series. 
 

Top right photos: George Roff

SST map: Iliana Chollett-Ordaz

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Summertime coral spawning

Summer is often a time of great excitement in the Caribbean and not for the reasons you may be thinking. It’s usually stony coral spawning season between the months of August to October and coral reef scientists are often anticipating this event. Some just wish to witness this amazing event when the corals release eggs and sperm into the sea to be fertilised, whilst others wish to record data. One of our partners, the Rotterdam Zoo takes it one step further; they collect gamete (sperm and eggs) samples to transfer to a lab for rearing.

The Rotterdam Zoo has a long track record of rearing corals. They have successfully reared the endangered Caribbean Elkhorn coral from gametes collected in the sea. During the FORCE project they will raise corals from the Elkhorn and Staghorn corals. These lab-raised young corals will be transplanted back into the sea at various stages of their growth. The scientists will then compare how the lab-raised corals survive against those that are naturally growing in the sea.

There has been much anticipation across the Caribbean during this time. Predictions for 2010 spawning events are made based on past years’ spawning events. In some parts of the Caribbean coral spawning begins early, as was shown by observations in Belize out at Carrie Bow Cay during July (from 25th full moon until 1st August). For a few nights, Acropora palmata, the scientific name for the Elkhorn coral, were observed spawning. Many colonies released sperm cells and egg bundles and for many it was the entire colony. The Acropora cervicornis or Staghorn coral also released gametes approximately 20 minutes after the Elkhorn.¹

Elkhorn corals were also observed spawning at night at the end of July within the Puerto Morelos Reef National Park in Mexico.² However, these were just corals from the western Caribbean, our partners Dr. Dirk Petersen at Rotterdam Zoo and Dr. Mark Vermeij from CARMABI (Caribbean Research and Management of Biodiversity) on Curacao were more concerned with what was going to happen in the southern Caribbean.

At CARMABI they had spent a lot of time observing spawning from last year and had set predictions for this year for various coral species (see http://www.researchstationcarmabi.org/images/stories/file/CORAL%20SPAWNING%20PREDICTIONS%20SOUTHERN%20CARIBBEAN%202010.pdf). In the southern Caribbean, specifically Curacao, where the team works, the predictions were made for the stony corals to spawn from the middle of September to October this year. The team, therefore, were vigilant from the 25th of August because they know that despite all the predictions, coral spawning can be unpredictable business.

They were prudent to begin monitoring in August as the team has reported spawning of Acropora palmata and Acropora cervicornis in Curacao (Sea Aquarium reef and Spanish Waters) between the 26th to 28th August nights, typically between 9-10pm. This means they were able to collect gametes from Elkhorn and Staghorn corals. Besides being in the right place at the right time, collecting the eggs and sperm has to be precise, co-ordinated and quick work.

The eggs and sperm that were collected from the two coral species were taken to the lab to be fertilised and they will be reared at the coral culture lab at the Curacao station. As you can see from the team’s weblog (http://www.secore.org/gsp.dll?sid=283&pid=1&p_menuid=136&p_parentmenuid=86) correct timing is crucial and they had to get the eggs and sperm back to the lab very quickly as coral sperm only have a useful period of 1-2 hours after being released. They managed to fertilize and to get everything set up and now the rearing of the larvae will begin. Throughout the next year, the team will put their coral parenting skills to good use!
¹Raphael Ritson-Williams, Marine Chemical Ecology, Smithsonian Marine Station,
² Dr. Anastazia T. Banaszak,Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México

Photos courtesy of Mark Vermeij

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Coral Histories in Mexico

Working on one of the most interesting areas of research are our partners at ECOSUR. At their lab in Puerto Morelos on the Yucatan Peninsula of Mexico, the team are working on analysing density banding of corals. In March they began collecting coral samples at Banco Chinchorro, Mexico.

What is involved in looking at density banding? First, it is important to note that as corals grow they build skeletons. New skeleton is generated within the living tissue layer which always remains as a thin band (several millimetres wide) at the outermost surface of a colony. Reef coral sclerochronology, developed in the 1970’s, shows that an annual growth pattern of the skeletons of some massive stony corals can be seen in X–radiographs of skeletal slices as high and low density bands. Such banding has provided invaluable information about coral growth rates and the environmental conditions under which growth took place in these areas.

Nancy Cabanillas-Terán, the team’s postdoctoral researcher, says they have collected cores of Montastraea faveolata. What is Montastraea faveolata? Montastraea is a type of hard (stony) coral that includes the boulder coral and the great star coral. Montastraea are one of the major reef-building corals in the Caribbean.

Why are they being sampled? These coral and the reefs they form contain their own history in their structures. Some massive coral species grow to be several metres high and contain annual bands similar to tree rings. Growing at 0.5-2 cm per year, depending on the species, some corals can record several hundred years of growth.

Banding patterns help to ‘date’ the coral, showing the average growth for massive coral colonies. The ’growth characteristics’ for corals involves several features: skeletal bulk density (bulk density), extension rate and calcification rate. There is a calculation of the skeletal density and its annual extension rate that provides the annual calcification rate.

How does a scientist “core” a coral and get a sample? These large, living corals are usually sampled by drilling a core vertically from the top to the bottom of a colony. These cores are removed from the centre of the colony and the hole is plugged so that the surrounding coral tissue will overgrow it. This overgrowth happens quite rapidly with no harmful effects to the coral. 

Using a rock saw with a diamond-tipped blade, precise 9mm slices of the core are taken for X-ray analysis. The analysis of slices of the core reveals the annual banding in the density of the calcium carbonate skeleton and each year can be dated from the outer edge which is the year the coral was collected. Interestingly, it is the same radiographic x-rays that are used on humans!

These annual density bands shows the corals’ growth rate but also provide clues to what the environmental conditions were during these periods, therefore they are useful for reconstructing environmental conditions and possibly for making predictions. As these massive “stony” (scleractinian) corals grow they absorb chemical tracers reflecting the environmental conditions in the surrounding seawater during skeleton building, for example water temperature. Modern corals from living reefs are said to provide continuous climate records going back several centuries.

One of the key things that this team will look at is the relationship between growth and temperature. Every group of corals has optimal temperature for growth. They will look at the differences in different species in different slices. Porites astreoides will also be sampled; this coral is an important and dominant genus of hermatypic (reef-building) coral. Porites brood or release live young rather than sperm and egg packets like most corals.

In light of climate change it’s important to look at how corals respond to what scientists call ‘thermal stress’. Some corals will sacrifice their extension (skeleton) over their density (girth) while some will sacrifice their thickness over their skeleton. From Dr. Juan Carricart-Ganivet’s work, we now know that Montastraea species respond by investing calcification resources to build thicker skeletons, meanwhile the Porites species growth strategy is to invest their calcification resources in extension. This information is a tool for more precise environmental reconstructions and predictions about these corals.

In Montastraea in particular, they will look at whether the corals have acclimated, which means have they been responding in the short term, say a few years, to changing temperature, versus whether the corals have adapted, which is a longer term change to changing conditions. The team have 20 years of temperature data and if they can match that data with information from 20-year old corals, there’s a story to be told.

Their work involves going out in a boat and diving into the sea in order to physically collect samples with a drill and saw. When the samples are returned to land they are taken to a laboratory for slicing and x-raying and then further analysis are done with computer programmes to analyse different types of data about density, calcification and skeletal properties.

Nancy loves working in the lab which is challenging because some of the techniques and analysis are quite new. She also loves the nature of ecology and the fact that they have to look at the ‘big picture’. What are the factors that influence what they see in the lab? It is worth analysing all the possible factors that influence and change how a coral grows.

What do “ojos” or “eyes” and corals have in common? Stay tuned for future installments to find out....

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Coral Bleaching Watch

Dr. Mark Eakin, Coordinator of NOAA (National Oceanic and Atmospheric Association) Coral Reef Watch and one of FORCE’s collaborators, has noted that their recent satellite data shows that sea surface temperature (SST) along the Florida coast and in the Florida Keys has taken a dramatic upturn since mid-May this year. SST or sea surface temperature is the water temperature of the layer of seawater at approximately 1 meter below sea level. 

He says that sea surface temperature in the region increased significantly in mid-May with a dramatic increase, near 2ºC over several days at some locations. 2ºC might not sound like lot, but if it is a consistent rise during the summer months when the temperatures are already high, then it could pose problems for corals bleaching.

What is the danger with coral bleaching? Corals have tiny algae, zooxanthellae, growing  in their body tissue. Normally, these algae, which are microscopic plants, absorb energy from the sun and use it for photosynthesis or put simply, to produce food. They also give corals their normal, healthy colour. When the water gets too warm, these plants can't use the sun's energy as efficiently. The algae turn this excess energy from sunlight into toxic chemicals (that can cause damage to themselves and the coral). Even though the coral normally needs the algae, it has to get rid of them to survive this temperature stress. As a result, they eject most of the zooxanthellae. The coral is naturally transparent, and the rock underneath is white so the entire coral soon looks pale or white, making it appear "bleached."  Sometimes corals can survive bleaching, however, if the temperature gets significantly above the level by which corals begin to react or stays high for several weeks, severe bleaching will occur and some corals can eventually die.

Regarding the current temperature observations, Dr.  Eakin adds, “Another sea surface temperature hike started in early June and continues along the Florida coast, in the Keys, and also in the Bahamas.  These two events pushed the SST in the region way above what we have seen in our satellite data from the past 10 years for the region. At many locations, sea surface temperatures are now more than 1ºC above the highest observed at that time of the year.  At some places, SST has already reached a level that is not usually reached until late July to early August and pushes the temperature over the  point at which corals will begin to react to temperature stress and cause coral bleaching. “

The NOAA Coral Reef Watch satellite shows the Florida reefs in red [see image below] which means they are at Bleaching Watch or Bleaching Warning status. It also shows that through the Greater and Lesser Antilles and around the Caribbean coast of South and Central America are at Bleaching Watch as well.

Surface wind speed has been low during the days in June when the higher temperatures were noted in the region. If this low wind speed is persistent, it may accelerate the already significant warming.

Dr. Eakin says that what this could mean is that this summer is most likely a stressful bleaching season for the corals along the Florida coast, in the Keys, and in the Bahamas.  The forecasted active hurricane season may relieve the bleaching thermal stress (the stress caused by warmer-than-normal water which can trigger the corals to bleach) as the hurricanes did in 2005, but this will depend on storm tracks.

He notes, “Abnormally warm conditions have existed across most the Caribbean since January and our NOAA Outlook product, which is a bleaching prediction tool, shows potential for strong warming this year in the Caribbean and Western Pacific.”

For further information and imagery from NOAA’s Coral Reef Watch, visit http://coralreefwatch.noaa.gov/

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What's on the (Deepwater) Horizon?

Although the FORCE project does not have research experts on oil spill impacts on reef environments, one of our project collaborators, Dr. Claire Paris at the Rosenstiel School of Marine & Atmospheric Science (RSMAS) at the University of Miami has been looking at modelling the movement of the oil particles and the subsurface oil plumes as part of the University of Miami's Oil Spill Response team.

Using the Connectivity Modeling System (CMS), a 3D model developed by Dr. Paris, the lab is modelling forecast simulations, looking at subsurface oil movement trajectories because according to what is known about subsurface oil there are potential issues for marine organisms. They state that 1) Pollution by crude oil reduces the penetration of light in sea water, which can affect the behavior of planktonic organisms that utilize the light direction to feed, avoid predation, and for orientation.

2) The oil slick blocks the view of the Snell window. Snell window is a phenomenon by which under ideal conditions, a fish looking up at the water surface from underneath sees a perfectly circular image of the entire above-water hemisphere—from horizon to horizon. Snell's window compresses a 180° angle of view above water to a 97° angle of view below water. The oil slick affects the view of marine organisms such as mammals, turtles, and fish that use celestial compass to navigate in the open ocean.

The Paris Lab at RSMAS has calculated that the formation of the subsurface oil plumes could pose a much later problem for some marine life. According to the lab, water density increases with depth due to colder temperature and compression. Thus, the rising rate of the oil is slower at depth than in the lighter surface layers of the ocean. Because oil, mixed with gas, has been injected into the water column from the deep seafloor, the oil should form droplets with a range of sizes rising at different rates. In addition, the depth profile of the oil is expected to have a subsurface bulge due to reduced buoyant velocity below the pycnocline. The pycnocline is a layer in the ocean where there is a large water density difference between surface waters (or upper 100 metres) and deep ocean water. The water density increases rapidly with depth and this acts as a barrier to seawater mixing vertically. Calculations using Stoke’s Law, a law of physics, suggest that this bulge may be present below the pycnocline and extend to the sea bottom at close to 1,400 m, and will grow as long as oil is flowing from the well.

This accumulation of oil at deeper levels is subject to different horizontal flow paths than those from the surface of the ocean, and the potential for long-distance transport is a serious threat to planktonic organisms such as fish and lobster larvae, their food web in the water column, as well as to the bottom-dwelling community, including mesophotic corals which live at lower levels (from 30 to over 150m) and are light-dependent.

In addition to the threat posed by the enormous quantities of oil circulating in the Gulf of Mexico, the crude oil-gas mixtures have been further mixed with highly toxic dispersant directly injected at the well. This poses an even larger threat to the survival of both pelagic (open-ocean) and benthic (bottom-dwelling) organisms, and is particularly harmful to coral reefs.

The research raises questions about the future effects the oil spill may have on the reefs. Presently, this information is mainly for research guidance rather than for operational use.

There’s further information and some excellent diagrams at
http://www.rsmas.miami.edu/personal/cparis/cms/description.html

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UCME – fish traps

Hi, I’m Steve Canty I work for the project partner, the Utila Centre for Marine Ecology (UCME) in Honduras. Our role in the FORCE project is related to fisheries, primarily investigating the sustainability of the Yellowtail Snapper (Ocyurus chrysurus) as a fishery for the Caribbean, and a smaller part of our work includes assessing the vulnerability of parrotfish to fish traps.

We have been working with fishermen from the Utila cays who use fish traps. These fishermen target grouper and snapper species around the full moons during the months of December through March. This type of fishing uses a rectangular trap with a square mesh, quite different to fishermen in Jamaica, the Bahamas, Barbados, and many other islands within the Caribbean who utilize an Antillean z-trap.

The fieldwork started in April. Our work was greeted with interest and a certain degree of amusement by the fishing community… who would want to catch parrotfish and why would you be returning all of the fish from the trap back into the sea? They were also convinced that we would be wasting our time and be pulling up empty pots. We employed the services of one of the most experienced fishermen on the cay, Noel, who to avoid confusion on the boat started calling Dr Steve Box, the Big One, and myself (also Steve) the Little One. It’s a shame that you can’t always choose your nicknames. Once the location was decided upon, it was just a matter of setting the traps. Then later the same day we dived the areas of the traps, conducting fish transects to assess the fish populations within our selected site. This was done mid-morning and late afternoon at 2 sites, each having a set of 6 fish traps.

Day 2 consisted of hauling the pots for the first time, although not in very deep water. My hands, that had been used to typing away on my keyboard for the last three months, didn’t fair particularly well to the pulling of pots. Gloves were definitely put on the shopping list. These first hauls were quite exciting although they didn’t seem to catch that much, and seemed to be living up to the expectations of the Cayan community. The remainder of the day consisted of data entry, four fish survey dives, and large amounts of food. It’s hungry work pulling in traps! The remaining three days were pretty similar, starting at 05:30 and ending somewhere around 18:00. One of the highlights of each day was hauling up the traps to see what we had caught. It turned out to be mainly butterfly fish, with the odd surprise of small nurse sharks and queen trigger fish, and then a few unwelcome visitors of spotted eels and green morays… luckily Noel was on hand to deal with these. The Big One (Steve Box) had the joy of measuring all the fish we caught in the traps. He quickly grew a firm dislike to Squirrelfish, (that have razor sharp spines behind their gills and on all their fins) and was never the biggest fan of the spotted eels, especially when Noel would hand them to him head first. Probably the least fun part was identifying and measuring fish that were regurgitated by the spotted eels. Luckily I was at the bow of the boat recording data, far enough away from the fragrant aroma.

The other highlight and maybe the most enjoyable part of each day was either heading to or from the sites on a small dory (traditional fishing boat) with Noel, who would keep us entertained with a crude humor that would have us crying with laughter and nearly falling out of the boat. We ended this week having counted and measured a large number of fish, 835 trapped and 2887 surveyed to be exact, exhausted from the long hours and number of dives, but looking forward to returning to try the different trap type and listening to a few more of Noel’s stories.

The first day started early and finished late with a rather slow and unsteady pace, with the inevitable hammering of thumbs (mainly mine, and not always by me). We provided entertainment for half of the population of the cay who would come to sit just where we were working to tell us how and what we should be doing but without actually getting up  and doing anything themselves. Despite the unsteady pace by the end of the day we had managed to organize ourselves into a production line, one group constructing the frames and the other setting the two frames together. The bruises and heat of the day were compensated by a few cold beers at the end of the day, which helped a great deal.

So we arrived at Utila on the ferry. Noel was at the dock to pick us up and take us to the cays, and we were ready to get going the next day bright and early. We tested the trap.  They were a little light, so we attached a few weights to each of them to make sure that they would sink. When we were halfway through, Noel and I went and deployed them, whilst the Big One stayed behind and finished off adding the weights to the remaining traps. We then set the remaining traps and on our return Noel’s wife had made breakfast for us, “flitters” (similar to a scone but instead of baking it you fry it…obviously much healthier) with homemade mango jam, delicious.

We were then back into the old routine of our four fish transects per day: two at mid-morning and two late in the afternoon. We were both surprised by the number of fish, especially parrotfish, and the diversity, both this time and from the time before. On the fish transects we saw nurse sharks, eels, filefish, boxfish, a variety of snappers and grunts, surgeon fish, and lots of parrotfish. This made for interesting mornings and evenings of me calling out the names and sizes of the different fish that were seen on the transects, sounding very similar to a bingo caller… “Yellowtail parrotfish, intermediate phase, 19 (cm)”. It got a little interesting when a shoal of Blue tangs and Doctorfish swam across the transect.

The traps started catching the fishes very slowly. In the first few days we had quite a large number of zeros, which was a little frustrating, but over the week the catches picked up and seemed to confirm our thoughts from the previous study, Four-eyed butterfly fish really are the silliest fish out there. When swimming past the traps they were often the first fish in the traps, sometimes only moments after the trap had been returned to the water, and they made up the greatest proportion of the trapped fish by numbers for both trap types. The weekend ended on a good note with the last hauls of the traps being much greater than the previous days. Traps seem so much easier to pull when they are full or at least have something inside of them.

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FORCE kicks off

Early in March this year we had our kick-off meeting in Barbados. The meeting was the first time the entire consortium came together and it was a wonderful mix of scientists from the social and natural sciences. Our partners from the University of the West Indies, Cave Hill Campus hosted the meeting. Professor Wayne Hunt, Pro-Vice Chancellor welcomed the participants and Mr. Hubert Perr, Head of Operations for the European Union Delegation for Barbados and the Eastern Caribbean, opened the meeting.

For three days the principal investigators, technicians, post docs and PhD students discussed the project’s workplan and associated fieldwork. It was a productive time of information sharing and discussing ideas as the various disciplines came together as one group. The discussions on the integration of social and natural sciences were interesting and dynamic which bodes well for carrying out some novel work.

For some of the students it was a great opportunity to take part in discussions with a room full of leading scientists working on the Caribbean coral reefs. One student said, “It’s so exciting to have this wealth of expertise all together from whom I can ask questions; I don’t know where to start”. 

The CERMES team at UWI made us all feel very welcome. Now we have returned to our respective institutions equipped to move the project forwards. Watch this space to see what we are up to……

 

 

                                                    

FORCE kick-off meeting participants