Signs of resilience and recovery from the coral reefs of Florida


Here is some good news from the Caribbean – despite a >95% decline in staghorn coral since the 1970’s, there are some signs of resurgence:

Dropping 12 feet below the ocean’s surface less than a mile off Fort Lauderdale’s beach-front towers, a diver might wonder if he or she somehow got magically transported to a remote coral reef in the Caribbean.

Covering the sea bottom is a forest of maize-colored, healthy staghorn coral with grouper, grunts, damselfish and other assorted tropicals swimming all around. If not for the dusky, green water, bits of floating trash and gobs of algae covering some of the surrounding soft corals, the scene could be the Bahamas or Bonaire.

Why is a threatened species of coral thriving near urban Broward County? (Read More)

Live blogging the annual coral spawning event across the Caribbean


So it’s that time of year again in the Caribbean where the corals undergo the annual mass spawn. Along with this ritual comes the coral researchers, who run a bunch of experiments with coral recruitment, settlement, fertilization, which involves catching coral sperm and eggs using nets (see above) and mixing it all up in jars (see pictures here – honestly, i’m not kidding). Spawning time is usually pretty hectic for all researchers, as it’s generally a once a year sort of affair to raise and settle the larvae, and gather data to write papers and justify the next funding round.

This year though, it seems that research groups have taken up blogging the whole affair blow by blow, which makes for some great photographs and intense reading. Here are five of the best are in no particular order. Comment below if I’ve missed anyone out, and special mention to Mary Alice Coffroth and the Burr Lab for some spectacular photos!, :

1. Acropora Spawn Blog – Eric Borneman, Alina Szmant, Jennifer Moore and others:

“We were watching 3 sites again last (Sunday) night and as you can see from the SCUBAnauts post, there was some spawning at Molasses Reef again. Although it was a good volume, it was unfortunately all one clone. Sand Island only saw a few bundles. One clone (same one as Saturday night) spawned even more than last night at Elbow Reef but all the other clones kinda sat around twiddling their tentacles. Oddly enough the same tiny patch of tissue in the picture from last night’s post had a few (but even fewer) bundles but that was it from the others. So for any hope of fertilization we had to high tail it home to meet up witht he gametes collected from Mollases. Talk about artificial insemination! Since Puerto Rico saw very little last night too, we are hoping that tonight will be ‘the night’ but we are getting tired of saying that!”


2. Coral Spawning 2009 – Baums Lab,  Puerto Rico

“Our corals spawned last night!  We’ve been working around the clock (literally), keeping our various crosses alive and sampling them at odd hours.  It’s a simple rotation:  +1 hour after fertilization, +4 hours after fertilization, etc., but when the corals spawn at 9:30 PM, suddenly you need to be up all night long.  Throw in water changes, tank refills, and microscope work, and none of us have had a moment to spare, or sleep!  In five minutes we’re heading out diving again.  We split up the group and sent half to Bajo Gullardo–an offshore site with huge palmata stands–in an effort to increase the diversity of our crosses.  Rest assured we’re getting what we came for.  More to follow…”


3. Coral Spawning 2009 – Baums Lab,  Curacao

“Yesterday was our 5th night of diving and our 5th attempt at gathering the amount of coral spawn needed to carry out our study. Despite a consistent showing from one of our target colonies we have been unable to collect enough from any of the others to generate the number of larvae needed. Using the small volumes of spawn we have collected over the past few nights we are seeing that the larvae rearing system we have developed is working very well.  Larvae from last night’s cross have advanced to the “cornflake” stage by 9am this morning and the larvae from 4 nights ago are already swimming happily in their kreisel. So, although we may not be able to run the full experiment this month in Curacao, with luck we should succeed in settling some larvae on tiles to plant back out on to the reef.”


4. Burr Lab – Long Key, Florida

“Spawning is not expected until Monday, but on Saturday the team went to Chica Rocks for a “practice” run of the spawning drill. This is a site with abundant heads of Montastreae faveolata. We arrived on the site at about 7 pm and jumped in the water to deploy the spawning tents. Then we returned to the boat to wait until dark. We enjoyed the evening breeze, watch the moon rise and discussed protocols on the boat until 10:00 to 10:30 and then return to the reef to check for spawning. The divers swam around for about an hour and then collected the tents and returned to the boat at 11:30. After an hour ride back to the lab, we quickly cleared up all of a gear and headed to bed. A great first night out and now we are ready!”


5. SECORE Weblog 2009 – Curacao

“During the day we take care of our coral babies. Some of them should be getting close to their swimming phase. Then the regular drill starts again. Prepare nets and diving equipment, have diner and take of to our dive sites. We do have a little lock up accident this evening. Someone did not seem to want Mitch to join in the fun… He got locked in in his room. After some running around for keys we manage to set him free. Luckily he won’t have to miss out on the last night of diving. We don’t know what to expect, but we keep on hoping for the best”


Local stressors act to reduce the resilience of corals to bleaching events

Researchers from SCRIPPS Oceanographic Institute have published an important article in the journal PLoS ONE, detailing research that confirms what has suspected for some time – that local stressors reduce the resilience of corals to bleaching events.

Jessica Carilli and colleagues set out to test the hypothesis that chronic local stress reduces coral resistance and resilience to bleaching, by investigating coral growth before and after the 1998 bleaching event in Belize. The authors took over 90 coral core samples from sites with relatively high and low chronic stress, and determined changes in growth rate over the past decade (much like the declining calcification on the GBR Science paper released earlier this year).

The results are striking – after the 1998 bleaching event, the massive star corals (Montastraea faveolata) from ‘healthy’ reefs (low chronic stressors) were able to to recover and grow normally within two to three years, whilst star corals from unhealthy (high chronic stressors) reefs showed no sign of a complete recovery in the 8 years following the bleaching event.

(A) Coral without the 1998 growth suppression, indicating resistance to bleaching in 1998. (B) Coral with the 1998 growth suppression, recognized by the bright high-density band, but with a quick return to pre-1998 extension rates, indicating resilience after bleaching. (C) Coral with the 1998 growth suppression and continuing depressed extension rates after 1998, indicating a lack of both resistance and resilience to bleaching. (D) A coral with relatively high average extension rate. (E) A coral with relatively low average extension rate. (F) A coral with a partial mortality scar on the left (noted by white arrow), coincident with the 1998 growth anomaly.

(A) Coral without the 1998 growth suppression, indicating resistance to bleaching in 1998. (B) Coral with the 1998 growth suppression, recognized by the bright high-density band, but with a quick return to pre-1998 extension rates, indicating resilience after bleaching. (C) Coral with the 1998 growth suppression and continuing depressed extension rates after 1998, indicating a lack of both resistance and resilience to bleaching. (D) A coral with relatively high average extension rate. (E) A coral with relatively low average extension rate. (F) A coral with a partial mortality scar on the left (noted by white arrow), coincident with the 1998 growth anomaly.

“You can imagine that when you are recovering from a sickness, it will take a lot longer if you don’t eat well or get enough rest,” said Jessica Carilli, Scripps graduate student and lead author on the study. “Similarly, a coral organism that must be constantly trying to clean itself from excess sediment particles will have a more difficult time recovering after a stressful condition like bleaching.”

“It is clear that Mesoamerican corals really fell off a cliff in 1998 — nearly everybody suffered mass bleaching,” said Dick Norris, Scripps professor of paleooceanography and co-author of the study. “There are no pristine reefs in the region, but the ones in the best shape clearly are more resilient than those that are long-suffering. It shows that a little improvement in growing conditions goes a long way in recovering coral health.” (Read More)

Almost as striking are the obvious ‘scars’ left by the 1998 bleaching event, as evidenced by the decline in coral growth (annual extension rate) across all four sites:

Picture 610

Means (solid lines) and 95% confidence intervals (shading) for extension rates after 1955. Extension rates at Sapodilla and Utila remain suppressed after the 1998 bleaching event.

The authors show that the fastest recovering corals were collected from the offshore site at Turneffe Atoll, whilst the more heavily polluted sites at Sapodilla Cayes and Utila in Honduras suffer from significant impacts linked to local factors such as development, sewage and runoff. Considering that the entire Mesoamerican Barrier Reef was bleached during the 1998 bleaching event, it’s great to see that ameliorating local impacts can have a significant effect on reducing the effects of regional-scale bleaching:

“… local conservation efforts that reduce stress, such as reducing runoff by replanting mangroves at the coast or protecting an area from overfishing, could have significant impacts on the ability of corals to withstand the effects of climate change. Future research could investigate whether this interaction between local and global stressors extends to other coral species.”

Citation: Carilli JE, Norris RD, Black BA, Walsh SM, McField M (2009) Local Stressors Reduce Coral Resilience to Bleaching. PLoS ONE 4(7): e6324. doi:10.1371/journal.pone.0006324

NOAA Coral Bleaching Outlook System Indicates Potential for High Level Coral Bleaching in the Caribbean and Parts of the Equatorial Pacific

Scientists from NOAA’s Coral Reef Watch Program are forecasting a significant potential for higher than normal thermal stress in the Caribbean, especially in the Lesser Antilles, through October 2009. Continued high water temperatures can lead to a high probability of significant coral bleaching and infectious coral disease outbreaks.  The forecast is based on the July NOAA Coral Reef Watch outlook.

Scientists are concerned that bleaching may reach the same levels or exceed those recorded in 2005, the worst coral bleaching and disease year in Caribbean history. There is also some potential for high stress in the central Gulf of Mexico and a region stretching from the Lesser Antilles, including the US Virgin Islands, across to Puerto Rico, and across to the southern coast of Hispaniola and the Caribbean coast of Nicaragua.

Picture 606

Other areas of concern for coral bleaching this year are the central Pacific region including the equatorial Line Islands and Kiribati.  Some thermal stress may also develop between the Northern Mariana Islands and Japan.

An important caveat is that the model used for this outlook is not yet calling for El Niño development, whereas NOAA’s operational Climate Forecast System is now calling for development of an El Niño during 2009-10. If El Niño continues to strengthen, this could increase the bleaching risk in the central to eastern Pacific and Caribbean.

Just like any climate forecast, local conditions and weather events can influence actual temperatures. However, we are quite concerned that high temperatures may threaten the health of coral reefs in the Caribbean this year.

The Thermal Stress Outlook is based on sea surface temperature (SST) forecasts generated by the Linear Inverse Model (LIM) from the NOAA Earth System Research Laboratory. This system is the first to use sea surface temperature forecast models to provide seasonal outlooks of bleaching around the world.

Picture 607

In the Pacific, the area of concern includes the equatorial Line Islands and Kiribati. This area is especially subject to stress if El Niño development continues.  There is a potential for some thermal stress to develop between the Northern Mariana Islands and Japan. There is also some indication of thermal stress along the Pacific coast of Mexico. However, the model is only generating small areas in the Pacific with a potential for abnormally high temperatures. Care should be taken that areas of warming in open areas of the Pacific are likely to move from the locations seen in the current forecast models. This region is also subject to intensification during El Niño conditions.

The NOAA Coral Reef Watch forecast comes on the heels of NOAA’s National Climatic Data Center reporting in June that the world’s ocean surface temperature was the warmest on record, breaking the previous high mark set in 2005, the last year of record-setting global coral bleaching incidents. Updates can be found here. Divers who see bleaching can report it at ReefBase.

In its inaugural year the forecast system did well in predicting the general patterns of mild Caribbean stress in 2008 and high thermal stress in the western Pacific in 2008-9, especially earlier in the season. The guidance issued in early December provided valuable guidance on the potential for bleaching 2-4 months in advance. The general pattern of warming in the outlook corresponded well with large-scale patterns of actual thermal stress. However, strong monsoonal activity along northeastern Australia cooled waters on the Great Barrier Reef (GBR) reducing thermal stress there. This was a fortunate difference between the forecast and actual conditions that protected these valuable reef resources.

Testing the ‘macroalgal dominated coral reefs’ paradigm

The paradigm of ‘coral vs algae’ has become entrenched in coral reef science over the last few decades. The classic example of this paradigm in the Caribbean was from a paper published byTerry Hughes in a 1994 article in the journal Nature, entitled “Catastrophes, Phase Shifts and Large-Scale Degradation of a Caribbean Coral Reef”. The paper documented a series of disturbances in the late 1970’s and early 1980’s, including two major hurricanes, a disease outbreak and the loss of a seaweed-grazing urchin, after which coral cover declined dramatically from ~70 percent cover to less than 10%, and macroalgal cover to rose to almost complete dominance >90% .


Temporal trends of coral and algae on Jamaican Reefs (top left, 1975 - 1995, Discovery Bay showing dramatic declines and corals and corresponding dominance of macroalgae, top right 1995 - 2004 from Dairy Bull Reef showing a rapid recovery and reversal of the macroalgal phase shifts)

Since then, reefs throughout the Caribbean have undergone dramatic declines in coral cover, leading to the regionwide collapse of the two dominant reef building corals, Acropora cervicornis and Acropora palmata. One ‘good news’ story did come out from a neighbouring reef in Jamaica called ‘Dairy Bull’ reef, where Joshua Idjadi and a team reported a doubling of live coral cover over the last decade, resetting the balance from a macroalgal dominated reef to a coral reef.


Photograph of Dairy Bull Reef in 2003 showing the recovery of the branching coral Acropora cervicornis. No macroalgae to be seen!

Since this iconic case study, a considerable quantity of scientific literature has been devoted to management principles, herbivorous grazing pressure and the reversal of macro-algal dominated reefs. However, documented examples of regional ‘phase shifts’ between coral and algae in the literature are surprisingly few and far between (asides from a few notable exceptions). John Bruno & Elizabeth Selig, two coral reef researchers who have developed a considerable dataset on coral reefs throughout the world, decided to test this assumption by randomly samply for regional trends and patterns in algal cover – much the same as an epidimiologist would determine the generality of case reports in the medical literature.

John and his team trawled through an immense number of reef surveys (3,500 to be exact) from over 1,800 reefs across the globe between 1996 and 2006, and developed a ‘phase shift index’ based upon corals and macroalgae. They then tested this index in four geographic regions (Greater Caribbean, Florida Keys, Indo-Pacific and the Great Barrier Reef) to see if the severity of phase shifts altered over the decade between 1996 – 2006. Their findings were  surprising, and might prove to be somewhat controversial…


A coral reef in the Caribbean dominated by macroalgal cover

Whilst phase shifts were indeed more common in the Caribbean than elsewhere, very few of the worlds reefs fell into either a stable ‘coral reef dominated’ or a ‘macroalgal dominated’ category. Furthermore, the ‘severity’ of phase shifts at a regional level was much less severe than the classic examples of macroalgal dominance, such as the Jamaican coral decline story. The data also suggested that there was no trend (>1995) towards macroalgal dominance in the Florida Keys or Indo-Pacific. Coral cover during this period (1996 – 2006) did decline (primarily due to crown of thorns starfish plagues), but their was no corresponding increase in macroalgal cover at all during this time.

Bruno et al argue that the apparent mismatch between the local scale descriptions of macroalgal dominance and regional scale patterns was caused by a gross generalisation of a relatively small number of ‘atypical’ case studies. This in itself is no small finding, and may go along way to altering the way we manage coral reefs. These findings may be somewhat controversial, it’s hard to disagree with the data. In what’s bound to throw the proverbial cat amongst the pigeons, the authors conclude:

“Since the Jamaica story was an anomaly, it makes a poor foundation for general models of reef ecology (e.g., Knowlton 1992, Bellwood et al. 2004 ). The current paradigm of reef management and ‘‘resilience’’ is based in large part on the perception that most of the world’s reefs are being overrun by seaweed (Szmant 2001, Precht and Aronson 2006, Knowlton 2008). This belief led to the argument that reef managers should focus primarily  on conserving herbivores or water quality (Szmant 2002, Pandolfi et al. 2003, Bellwood et al. 2004 ). While these are clearly important objectives of management, our analysis suggests that the macroalgae problem has been exaggerated.

Overfishing and poor land use practices may trigger widespread coral to macroalgal phase shifts in the future, but to date, the principal form of coral reef degradation has been the loss of reef-building corals, with only limited and localized increases in macroalgae. Therefore, the primary goal for reef managers and policy makers should be the conservation of coral populations, without which the entire system would collapse.”

Disease-hunting scientist: Dr Laurie Richardson and black band disease in coral


Just finished reading a great excerpt from a book called ‘Disease-hunting scientist’ by a Canadian author called Edward Willett. The scientist in question is Dr Laurie Richardson from Florida International University, who is well known for her work on ‘black band disease’ (see image above) on Caribbean coral reefs. I’ve never read Willett’s work before (and can’t vouch for the book itself), but I’ve long respected Dr Richardson’s research into black band microbial communities, and the ‘interview’ offered a few intriguing insights. More below:

At 287,231 square kilometers, coral reefs are less than a tenth of a percent of the total ocean floor. But they support more than a million species of marine life. They are also dying, from pollution, overfishing—and black-band disease, among others.

Dr. Richardson started her career researching “microbial mats,” communities of microbes that live in the sulfur-rich water of hot springs. She then worked in Wisconsin on a NASA project that used satellite data in the study of aquatic ecosystems. That led to three years at NASA’s Ames Research Centre in California learning remote sensing and image processing, which in turn landed her in Florida with a NASA-funded grant to work on algal pigments and remote sensing.

One day, while she was diving for fun on a coral reef, somebody showed her an example of black-band disease-and she immediately recognized it as similar to the microbial communities she’d studied in hot-spring outflows.

She looked in the scientific literature, and no one else had made that connection. And that was how the research she’s now been doing for more than 15 years began. (Read more)

Where have all the big fish gone? Part II: A case study from the Florida Keys

Following on from two great posts by John and Albert on Carribean reef fish decline and coral collapse, I thought it’d be worth posting these visually stunning images from a recent publication by Loren McClenechan, titled “Documenting Loss of Large Trophy Fish from the Florida Keys with Historical Photographs“. Through analysis of historical photographs in the Florida Keys, Loren managed to piece together a convicing history of recreational fishing trends over the past half century. Large fish really were more abundant in bygone days: the average fish size caught in 2007 was a tiny 2.3kg, compared with 19.9kg in 1957, and that the average length of sharks declined by more than 50% in the same period. In this case though, a picture really is worth a thousand words.




Early 1980's



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New evidence from coral reefs suggest sea level rise occurs over ecological time scales

image003Paul Blanchon and his team have uncovered evidence of extremely rapid sealevel rise 121,000 years ago in one of the warm interglacial periods.  Basically by dating coral skeletons at a place called Xcaret (the beautiful place where a fossil Reef lies exposed), Paul was able to document an abrupt reef crest “back stepping” (essentially the reef crest suddenly appearing landward in a very short time).   The abrupt loss of the lower reef crest growth but continued growth between the lower and upper reef crests has allowed these paleobiologist to draw the conclusion that this occurred due to a 2-3 m sea level rise.  What is the big news, is that it happened over decades.  Measurements of the upward growth of some corals at the “ocean surface” occurred at about 36 mm per year!

Paul is scientist who is characterised by rigour and excellence. He is based at Institute of Marine Sciences and Limnology (ICML) of the National Autonomous University of Mexico (UNAM) in Puerto Morelos on the Yucatan Peninsula.  As a paleobiologist, he is interested in how the world has changed over thousands of years.  For a long time now, Paul has been gathering evidence the great ice sheets the world can break up suddenly over very short period of times.  This latest paper is further evidence of the veracity of this idea – follow this link to see the article in Nature.

Editor’s Summary
16 April 2009

An interglacial jump in sea level

The potential for future rapid sea-level rise is perhaps the greatest threat from global warming. But the question of whether recent ice loss from Greenland and Antarctica is the first indication of such a rise is difficult to answer given the limited duration of the instrumental record. New evidence from an exceptionally exposed fossil reef in the Xcaret theme park in Mexico provides a detailed picture of the development of reef terraces, erosion surfaces and sea-level excursions in the region during the last interglacial. A combination of precise uranium-series dating and stratigraphic analysis, together with comparison with coral ages elsewhere, suggests that a sea-level jump of 2 to 3 metres occurred about 121,000 years ago, consistent with an episode of ice-sheet instability towards the end of the last interglacial. On that evidence, sustained rapid ice loss and sea-level rise in the near future are possible.

Death of corals is oceanographer’s murder mystery

There is a nice story in today’s News and Observer, the local paper for the Research Triangle,  in North Carolina.  Wade

“Marine scientist John Bruno became interested in coral reefs as a boy snorkeling in the turquoise waters off the Florida Keys above reefs of golden corals the size of football fields.

“It just went on for acres and acres,” recalls Bruno, 43, an associate professor at UNC-Chapel Hill. “They were just full of fish. We’d see hammerhead sharks on the reef and big critters. That is all gone. The corals are gone and the big fish are gone,” he says. “That’s happened in my lifetime.”

“It’s a wonderful murder mystery for ecologists,” says Bruno, who has been the studying the effects of disease and warming sea water on coral reefs. “It’s not obvious what the cause is. There are lots of potential culprits.”

Among the suspects are pollution, destructive fishing practices, predators that feed on corals, disease and warmer ocean waters.

In the ocean, reef-building corals, which are marine polyps, a class of animals, typically exist in colonies of many identical individuals. They fill the role of trees in a forest, Bruno says. The skeletons of corals create the hardened framework of a reef and, over time, build up and provide habitat for thousands of other animals and plants. Corals require warm, clear water and are sensitive to temperatures.

A warming of the ocean by just a degree or two for a few weeks in summer can disrupt the life cycle of corals, Bruno says. Reef-building corals contain tiny plant-like algae that live within their tissue in a mutually beneficial relationship. The algae provide the coral with food and oxygen, as well as the vibrant colors for which corals are known. In return, the organisms receive shelter and nutrients.

Bush administration considering two massive Pacific marine reserves

One of the many big political surprises in the US yesterday was news that the Bush administration was considering implementing two or more massive marine reserves in US territories in the Pacific.  The move  would protect some of the regions most remote coral reefs.  What isn’t so surprising is that, according to the Washington Post, über vice president Dick Cheney is trying to scale back or block Bush’s plans (doesn’t the former work for the latter?).

Read the whole story in the Washington Post here.

President Bush’s vision for protecting two vast areas of the Pacific Ocean from fishing and mineral exploitation, a move that would constitute a major expansion of his environmental legacy, is running into dogged resistance both inside and outside the White House and has placed his wife and his vice president on opposite sides of the issue.

In 2006 he designated the nearly 140,000-square-mile Papahanaumokuakea Marine National Monument in the northwestern Hawaiian Islands, creating what at the time was the world’s largest protected marine area. Scientists have advocated designating more such areas to protect them from the effects of overfishing, pollution and global warming, which are degrading oceans worldwide.

“There’s pretty strong evidence that everyone will benefit from the establishment of no-take reserves,” said Jane Lubchenco, a professor of marine biology at Oregon State University, adding that fish populations rebound both within the protected reserves and in nearby fishing grounds. “The administration made a major step forward in designating the Papahanaumokuakea National Monument, but that one alone is not enough to protect the full range of places and habitats and species that need to be protected. It will be part of [Bush’s] legacy, but his ocean and environmental legacy could be much, much more.”

One of the two marine reserves, or “marine conservation management areas”, includes a wide swath of the central Pacific ocean and some of the world’s most remote and pristine coral reefs, such as Kingman Atoll in the Line Islands.

Sadly, the article also highlights how close we came to having some similar reserves implemented closer to the continental US:

Bush initially explored the idea of establishing other protected areas closer to U.S. shores, including one off the southeastern coast near a group of deep-sea corals and another in the Gulf of Mexico. After commercial and recreational fishing interests and oil companies objected, the administration decided to pursue existing resource-management plans in those areas instead.

Political analysts interpret these moves as an attempt by Bush to build some sort of legacy before leaving office in early 2009.  We should know later in the year whether any of his planned reserves are indeed implemented.  And if they aren’t, I suspect the next president will be even more amenable to such logical solutions to some of our major environmental crises.

“Protecting places like this is one of the few things a sitting president can do that will live on in posterity and be remembered long after the other decrees and orders have been forgotten,”  said Joshua Reichert, managing director of the Pew Environmental Group.  “It would signal to the nation and the world that the sea needs to be treated as a threatened resource, and it will open up an era of global ocean conservation.”

Claudia McMurray, the U.S. assistant secretary of state for oceans, environment and science, said the administration will be “working up until the last week” of Bush’s term on the initiatives.  “While it would take a significant amount of work, we haven’t ruled it out,” she said. “We feel fairly confident, scientifically, there are so many unique species in that area, from that standpoint, we think it’s important to wall off as much as we can.”