In the Wake of Destruction: a Future for the Corals in the Great Barrier Reef

Posted on April 19, 2016 by ams13

This past month brought a lot of bad news with a slight silver lining to the corals in the Great Barrier Reef. Unfortunately, the bleaching we were starting to see at the time of my last entry only continued, worsened, and even lead to mortality in some cases. National Geographic reported 75% of the northern GBR reefs being affected by the current mass global bleaching event [1].

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Image of bleached corals off of Lizard Island in the GBR [6].

Australia’s National Coral Bleaching Taskforce reported in a survey of 520 individual reefs in the area between Cairns and Papua New Guinea that only four reefs showed no signs of bleaching [2]. Coral bleaching is not immediately a death sentence. If conditions improve (i.e. water temperatures cool down) then the symbionts that had been expelled from the coral tissue during the bleaching event can be replaced by new symbionts, and the coral can regain a healthy balance with these microorganisms and live. The truly devastating news from the bleaching in the northern GBR is that in a follow up survey to the one mentioned above, scientists reported approximately 50% of the surveyed bleached reefs exhibiting mortality [3].

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Photos from aerial survey showing coral bleaching in the northern GBR [7].

While so much damage has already been done to the once pristine North GBR reefs, it looks like the bleaching event is finally over in the area. NOAA satellite predictions indicate that the area is currently at a watch level, whereas last month we saw many areas in alert level 1 and some in alert level 2. Hopefully these projections will ring true, and one week out from now the area will revert to a no stress level.

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Maps depicting alert level for coral bleaching in the Northern GBR. The area remains at watch level during this week but is predicted to switch to no stress levels soon and remain there [8].

A recent paper published in Science on April 15th showed how previous bleaching events in the GBR fostered a thermal tolerance mechanism in reef-building corals [4]. The process they describe is a form of acclimatization in corals, in which “sub-lethal pre-stress events reset physiological and molecular mechanisms that underpin the innate stress response, and provide a means to survive subsequent stress events” [4]. Meaning that if a coral is exposed to high temperatures and survives, the next time it encounters high temperatures it is more likely to survive again having built up a mechanism to counteract the high temperatures during the first exposure. At least that’s the idea. The authors go on to prove that this mechanism is present in the GBR and has played a role during past bleaching events. They found that corals and their symbiodinium that had been exposed to sub-lethal, pre-stress temperatures (which have been prevalent in the GBR over the past 27 years) developed thermal tolerance. The corals that experienced single and repetitive bleaching temperatures, however, did not acquire thermal tolerance and suffered loss of symbionts and tissue.

Coral cell death (bars) and Symbiodinium density (lines) at bleaching for projective, single, and repetitive bleaching [4].

The concern of sea surface temperatures rising above the “sub-lethal, pre-stress” levels have come true during this last bleaching event, and thus the predictions made in the paper have come true, evidenced by the mass bleaching and mortality reported previously. Projections regarding total percent coral cover on corals associated with protective, single, and repetitive bleaching are also included in the paper.

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Total Coral Cover projections for the next century under protective, single, and repeated bleaching trajectories [4].

These graphs clearly show a negative correlation between amount of bleaching and total coral cover. Corals subject to single and repetitive bleaching are projected to have less than 10% total coral cover by just 2030. While these projections are limited in they look at only corals from the GBR, it is likely that the trend can be extrapolated to other reefs. Additionally, the GBR is the second largest home of coral reefs in the world, so losing them would have a dramatic effect on the global coral population [5].

The silver lining to this situation is that at least the GBR has received notable amounts of global media coverage in the past few weeks. The New York Times ran a cover story on coral bleaching and discussed the GBR [3]. That being said, as you can see from the many other entries on this blog, this bleaching event has reached many other coral reefs all over the world that have not received the same amount of media attention. But at least the world seems to be starting to pay attention. In order to avoid the forecasts of minimal coral cover, however, more needs to be done, and quickly. This next decade will prove critical in determining the future of coral reef health. If we want to save this ecosystem, then we must act now.

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Photo from aerial survey of northern GBR [7]. The GBR is the second largest coral reef area in the globe, and the northern section was the most pristine part of the reef.

References

1: Greshko, Michael. National Geographic. Web. 14 April 2016. http://news.nationalgeographic.com/2016/04/160414-great-barrier-reef-coral-bleaching-australia-climate-change-science/

2: Arc Centre of Excellence for Coral Reef Studies. Web. 2016. http://www.coralcoe.org.au/media-releases/coral-bleaching-taskforce-documents-most-severe-bleaching-on-record

3: Innis, Michelle.”Climate-Related Death of Coral Around World Alarms Scientists.” The New York Times. 9 April 2016. Web.

4: Ainsworth, T. D. et al. “Climate change disables coral bleaching protection on the Great Barrier Reef.” Science. 15 April 2016. Web.

5: Sheppard, C. R. C. et al. “The Biology of Coral Reefs.” Oxford University Press. 2009.

6: XL Caitlin Seaview Survey. Photograph. National Geographic. 14 April 2016. http://news.nationalgeographic.com/2016/04/160414-great-barrier-reef-coral-bleaching-australia-climate-change-science/#/01greatbarrierreefbleach.ngsversion.1460667600268.jpg

7: Terry Hughes. Photographs. ARC Centre of Excellence for Coral Reef Studies. 2016. https://www.dropbox.com/sh/yj8tt2mj5u0inmb/AAAW6D3V0eo7YVFkqAdLzhAMa/Images?dl=0

8: Far Northern GBR Satellite Coral Bleaching Alert Area and Outlook. Image. NOAA Satellite and Information Service Coral Reef Watch. 17 April 2016. Web. http://coralreefwatch.noaa.gov/vs/gauges/gbr_far_northern.php

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As effects of El Niño decrease, Hawaiian corals may still experience bleaching

Posted on April 19, 2016 by Sasha

The past month has brought with it some of the worst coral bleaching in recent years. The severity of the bleaching brought it to the attention of the New York Times, which ran a front-page article on the global bleaching event on April 10. The article provided a short summary of the current extent of the bleaching. Kiribati and the Great Barrier Reef have been more affected than any other reefs at this point in time. Parts of Kiribati are already appearing brown and fuzzy, which means that the corals have died and are being overgrown with macroalgae [1]. The northern part of the Great Barrier Reef has long been considered to be one of the most pristine reefs in the world. Unfortunately, scientists are predicting 50% mortality for the northern part of the reef (Figure 1). Luckily, the remains of a typhoon passed over the southern third of the Great Barrier Reef and were able to bring cooler water and increase the turbidity of the water, which gave the corals temporary relief from the heat and direct sunlight. The southern part of the reef will not see as much bleaching as the northern reef [2].

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Figure 1. Bleached coral at Lizard Island in March 2016. source: XL Catlin Seaview Survey

Fortunately, these past few months have left Hawaiian reefs intact. The “Blob” of hot water that has been stretched between the Americas and Southeast Asia and Australia hasn’t expanded up to Hawaii yet. Instead, the Blob appears to be getting smaller, which bodes well for Pacific reefs [1]. The hot water transported by El Niño has also missed Hawaii. The next area affected by El Niño will most likely be the Indian Ocean, which is already starting to experience some bleaching, especially in the Maldives [3]. However, Coral Reef Watch is predicting that temperatures in the northern Pacific Ocean will continue to increase throughout the year (Figures 2 and 3). This makes sense intuitively because the northern hemisphere is just now reaching its hotter months, whereas the southern hemisphere is finally coming to its colder months. Sea surface temperature (SST) largely follows seasonal patterns but lags a bit behind.

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Figure 2. Coral reef bleaching risk predictions for April – July 2016. source: NOAA Coral Reef Watch

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Figure 3. Coral reef bleaching risk predictions for week of August 28, 2016. source: NOAA Coral Reef Watch

Hawaii has not been completely unaffected by the conditions of the last few months. While SST has not gotten high enough to induce mass bleaching, it has been higher than normal (Figure 4). One measure of stress to coral reefs is “degree heating.” Degree heating is quantified using two parameters: the number of weeks that the SST has been that high and the difference between the average SST of the hottest month of the year and the average SST of the time period being observed [4]. For example, if a reef experienced a 4°C-heating week it could have experienced one week of temperatures 4°C higher than average, one week of temperatures 2°C higher than average and two weeks of temperatures 1°C higher than average, four weeks of temperatures 1°C higher than average, or a number of other combinations.

SST anomaly apr 18 2016

Figure 4. Sea surface temperature anomaly (°C) for April 18, 2016. source: NOAA Coral Reef Watch

Hawaii has not experienced any degree heating weeks (DHWs) in 2016, but had a stretch of almost 12°C-heating weeks in the fall of 2015. Figure 5 shows DHWs and temperatures for the island of Oahu. Last year (2015) is represented with the thin black line. The peak rising from the bottom right of the figure shows how much heat stress the corals had. This year (2016) is represented with the thick black line. Already, you can see that the temperature has been on the warmer end of the “normal” spectrum.

Oahu SST trends

Figure 5. Sea surface temperature trends for Oahu (January 1, 2001 – April 18, 2016). source: NOAA Coral Reef Watch

It is likely that more corals in Hawaii will bleach this fall, probably sometime around September. Predictions released by Coral Reef Watch trend towards higher temperatures in the northern hemisphere as the year progresses. The four-month outlook (April – July) reaches a “Watch” in Hawaii, and the weekly outlook for August 28 shows at least a Watch in most of the northern hemisphere (Figures 2 and 3). Based on these models and past temperature trends, it is not a stretch to predict more bleaching this fall in Hawaii.

It is becoming increasingly obvious that climate change and nutrient pollution are combining to have worse effects on coral than either would alone. In a study published in 2015, Michael Gil and colleagues found that herbivores might not be able to counter effects of nutrient addition in real systems. Previous studies have found that herbivores have an effect at small scales, but this research found that at larger scales herbivores are less effective [5]. The study has implications for coral survival because nutrient enrichment increases algal populations and thus increases competition with corals. Herbivores reduce some of this competition, but this study implies that herbivores may not be able to do enough.

Another study done by Keisha Bahr and colleagues provided some good news. Bahr looked at how sensitive five coral species native to Hawaii were to increased temperature and increased concentrations of carbon dioxide in the water. The study found that some coral species are particularly resistant to both high temperature and high carbon dioxide concentration. Overall, high temperature caused more mortality than high carbon dioxide concentration, but the study also found that the results varied between species. This has implications for predicting the health of corals in the future because it shows that each coral behaves differently [6].

Together, these studies remind us that although some corals are resilient, we must continue to make efforts to decrease our impacts on the ocean. The recent bleaching event is expected to continue on into 2017, which will make it one of the longest periods of stress for corals in recent history. If we don’t want corals to disappear, we must change our actions and increase our efforts to help corals survive.

References:

[1] Innis, Michelle. “Climate-Related Death of Coral Around World Alarms Scientists.” The New York Times, April 10, 2016. Accessed April 18, 2016.

[2] Cressey, Daniel. “Coral Crisis: Great Barrier Reef Bleaching Is ‘the Worst We’ve Ever Seen’.” Nature, April 13, 2016. Accessed April 18, 2016. doi:10.1038/nature.2016.19747.

[3] NOAA Coral Reef Watch. Maldives 5-km Bleaching Thermal Stress Gauges. Apr. 17, 2016. College Park, Maryland, USA: NOAA Coral Reef Watch. Accessed April 18, 2016.

[4] “NOAA Coral Reef Watch Methodology Page.” NOAA Coral Reef Watch. Accessed April 19, 2016.

[5] Gil, Michael A., Jing Jiao, and Craig W. Osenberg. “Enrichment Scale Determines Herbivore Control of Primary Producers.” Oecologia 180, no. 3 (November 14, 2015): 833-40. Accessed April 18, 2016. doi:10.1007/s00442-015-3505-1.

[6] Bahr, Keisha D., Paul L. Jokiel, and Ku’Ulei S. Rodgers. “Relative Sensitivity of Five Hawaiian Coral Species to High Temperature under High-pCO2 Conditions.” Coral Reefs, 2016. Accessed April 18, 2016. doi:10.1007/s00338-016-1405-4.

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The latest from Kenya’s reefs: almost in the clear

Posted on April 18, 2016 by mcj2

It’s mid-April now people. Where exactly are Kenya’s reefs in the current worldwide bleaching event? According to the Coral bleaching response guide 2016 (Western Indian Ocean) that was put together by CORDIO’s East Africa director, David Obura, we should be “monitoring bleaching, mortality, recovery” [1]. So what are the best practices for monitoring reefs? Ideally, you’d want to visit a site bi-weekly for the duration of the bleaching event [1]. However, costs are of course a huge factor, and many of the organizations monitoring reefs off Kenya’s coast are underfunded [2, 3]. With this limitation in mind, Obura suggests making sure to observe the peak of the bleaching, so mortality can be attributed to bleaching and not some other factor [1].

So far bleaching has been far less severe than predicted in this part of the world [4]. CORDIO’s bleaching alert for April 15th announced that a shift away from the rougher SE monsoon winds has resulted in a strong cooling effect over the past two weeks [5]. Additionally, the tropical cyclone Fantala began to make its way east and is predicted to further dissipate the current hot spot on April 18th [5]. Currently, CORDIO places the Kenyan reefs on the ‘warning’ alert level [report citation]. This level means there are could be warmer-than-usual condition which could potentially cause some bleaching [4].

WIO forecast as of April 18, 2016

Bleaching forecast as of April 15th, 2016. So far, minimal bleaching has occurred off Kenya’s coast, and it looks like the reefs are almost in the clear. source: http://cordioea.net/bleaching_resilience/wio-coral-bleaching-alert

Back in early March, Jennifer O’Leary, a marine ecologist at California Polytechnic State University, who has been working in the area since 2010 reported the observation in yellow near Mombasa [5]. O’Leary documented a low level of bleaching (1-10%) which was ‘spotty’, and a mortality rate of 1-10% [5]. The greed dot represents a report of no bleaching from Obura ten days after O’Leary’s [5]. The reefs did not however, escape the next month of this mass bleaching event unscathed.  Further north in the Watamu Marine National Park, three reports of bleaching were recorded [5].

Bleaching observations as of April 18, 2016. Yellow indicates low bleaching, orange indicates medium, and green indicates none. source: cordioea.net/bleaching_resilience/wio-coral-bleaching-alert

Bleaching observations as of April 18, 2016. Yellow indicates low bleaching, orange indicates medium, and green indicates none. source: cordioea.net/bleaching_resilience/wio-coral-bleaching-alert

The next report was made March 20th by Peter Musembi, who reported low (1-10%) levels of bleaching and a mortality rate of less than 1% [5]. Despite this seemingly mild observation, the corals that were bleached (largely Pollicopora) were “totally bleached white” [5]. Just up the shore, another report of low level bleaching was made three days later near the same location by Mishal Gudka of CORDIO [5]. Gudka reported more totally bleached corals, this time of the species Acropora galaxea [5]. The last recorded and most severe bleaching observation was made two weeks ago again by Musembi [5]. He estimated that between 10 and 50% of live coral had been bleached with Pocillopora and Acropora faviids taking the brunt of the bleaching [5].

Though we end our story on a bit of a low note, conditions on the reef are improving. Hopefully we can use the knowledge gained from observing this bleaching event to better prepare us for the future.

References:

  1. Obura, D. O. (2016) Coral bleaching response guide 2016 (Western Indian Ocean). http://cordioea.net/bleaching_resilience/wio-bleaching-2016.
  2. Obura, D.O., Tamelander, J., & Linden, O. (Eds) (2008). Ten years after bleaching – facing the consequences of climate change in the Indian Ocean. CORDIO Status Report 2008. Coastal Oceans Research and Development in the Indian Ocean/Sida-SAREC. Mombasa. http//:www.cordioea.org.
  3. Wilkinson, C. (2008). Status of coral reefs of the world: 2008. Global Coral Reef Monitoring Network and Reef and Rainforest Research Centre, Townsville, Australia, 296 p.
  4. NOAA Coral Reef Watch Methodology, Product Description, and Data Availability of NOAA Coral Reef Watch (CRW) Operational and Experimental Satellite Coral Bleaching Monitoring Products (2011) NOAA Satellite and Information Service.
  5. CORDIO: East Africa (2016) WIO Coral Bleaching Alert– what to expect?
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A Future for the Marshall Islands

Posted on April 18, 2016 by Hanna

Welcome to the third and final blog post tracking the progress of the Marshall Islands during a season of dramatic coral bleaching.  In the last post, I discussed the status of different coral species on specific atolls in the Marshall Islands.  This post will attempt to address the potential future trajectories of the coral reefs surrounding the Marshall Islands.

 

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http://www.headlines-news.com/2015/12/11/637852/uncertain-over-paris-climate-talks-marshall-islanders-prepare-for-the-worst.

Figure 1: A boat is moored in the lagoon at Majuro atoll in the Marshall Islands.

As time goes on and climate change advances, coral bleaching events will grow more frequent and severe [1].  How coral reefs are able to survive and recover from these events has some dependence on how humans will manage our relationship with nature in the future.  It is more important than ever to quantify environmental disturbances and re-evaluate how we protect coral reefs [1].

There are several solutions that exist to help protect the reefs.  In some more inhabited areas of the Marshall Islands, runoff and other ocean-altering practices can be more closely regulated to help reduce pressure on coral reefs.  In other areas, removal of herbivorous fish can be regulated and reduced in order to balance algal growth on reefs [1].

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http://www.huffingtonpost.com/entry/marshall-islands-climate-change_us_565f5337e4b079b2818cf643

Figure 2: An example of a bleached coral in the Marshall Islands, photographed in 2014.

Although this blog focuses on the reefs of the islands, the human populations in the Marshall Islands are also experiencing stresses due to climate change.  These are the people who can directly impact and help reef life, so it is important to discuss life on land as well.  Earlier last month, the Marshall Islands were declared to be in a state of emergency.  What are being called “king tides” have swept in and inundated the atolls in unusual and unprecedented amounts, forced over 1,000 people to evacuate and relocate to other atolls [2].  On average, the Marshall Islands are only 2 meters above sea level, making them very susceptible to flooding, but officials say that the amount is unusual, and in some placed, the sea has even reached the pools in the center of the atolls [2].  This loss of shoreline is very distressing, and will continue to be watched in the coming months and years.  This video is from the 2014 king tides, and it is shocking to think that the events have continued to worsen.

However, it is not all bad news.  Late last month, the Marshall Islands became the third nation (following Fiji and Palau, two other nations that have been similarly impacted by climate change) to formally ratify the global carbon-cutting climate agreement made in Paris [3].  Hopefully, resolutions like this one will help improve carbon output and slow the progress of climate change and ocean acidification.

It is difficult to monetize coral reefs.  They affect biodiversity, ocean health, and food security for dependent populations. Moving forward, it is of the utmost importance that we be responsible in our consumption of ocean products our production of carbon so that we can keep this flagship ecosystem around for years to come.

 

[1] Sheppard, Charles. “The Biology of Coral Reefs”. Oxford University Press. 2009. Pgs. 239-242; 289; 267.

[2] “Marshall Islands face evacuations as sea swamps capital”. http://www.climatechangenews.com/2014/03/04/marshall-islands-face-evacuations-as-sea-swamps-capital/. 3/04/2016.

[3] “Marshall Islands to ratify Paris climate agreement”. http://www.climatechangenews.com/2016/03/21/marshall-islands-set-to-ratify-paris-climate-agreement/.  3/21/16.

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The Galapagos: A Tale of Recovering Reefs

Posted on April 18, 2016 by aay1
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Location of Darwin and Wolf Islands in the Galapagos Archipelago

Hello there. Here is my last blog post about the Galapagos coral reefs. It really has been fun following the progress of this specific reef and I hope that I’ve raised at least a tiny bit of awareness for the ever-growing threats of coral bleaching. It’s also exciting to see links to my blog posts come up in my Google searches.

 

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Coral Reefs off the coast of Floreana Island in the Galápagos Islands photographed in 1976 (left) and 2012 (right). Photo credit: Peter Flynn and Derek Manzello

I stand by my previous post that there is hope for the Galapagos coral reefs, especially in the northern islands. The northernmost coral reef, Darwin Island, was first surveyed in 1975 and consisted primarily of frameworks of pocilloporid and poritid corals. After the 1983 El Nino caused severe coral bleaching there was near total loss of pocilloporids and extensive partial mortality of poritid corals. [1] Since the event Porites lobata, which has lower mortality rates than pocilloporid corals, has taken over as the predominant frame-building species. [1] Comparatively to pocilloporid corals, P. lobata is more thermotolerant and subsequently more successful at recruitment, making them the more resilient species. [1]

Adult lobe coral (Porites lobata) colonies can grow to be several hundred years old, providing habitat to small reef dwellers. Credit: Baums lab, Penn State University

A little bit about one of Adrienne’s favorite topics: different Symbiodinium species contribute to variations in the way corals respond to bleaching events. As a result, corals that are able to host more symbiont types are better equipped to cope with environmental perturbations. [5] In 2006, samples from the northern Galapagos Islands showed only the presence of clade C symbionts. Corals that host clade C symbionts are shade tolerant and grow faster than corals with clade D symbionts. [5] Further analysis of the distribution of Symbiodinium species in the Galapagos Islands will help us determine how the distributions influence coral persistence and coral dominance in future bleaching events. [1]

A microscopic image of Symbiodinium. Credit: Penn State University

Recent research projects have identified the Galapagos Islands as important for protecting some of the world’s most rare and vulnerable coral reefs. [2] A team of researchers took core samples from corals, examined their density bands, and produced 3-D X-ray images. [4] These images illustrated healthy annual growth rates and density patterns for corals in the northern waters. [4] New species to the Galapagos and science including zooanthid species from the genera Hydrozoanthus, Parazoanthus, Antipathozoanthus, and possibly Epizoanthus have been discovered. [2] Surveys have shown that Wolf and Darwin shelter 95% of the coral species in the Galapagos Marine Reserve, some of which are close to extinction and need special attention. [2]

The surviving reef off the coast of Darwin Island in the northern Galápagos Islands. Photo Credit: Joshua Feingold

One such project, Galapagos Coral Conservation: Impact, Mitigation, Mapping and Monitoring, aims to help the government of Ecuador protect its coral reefs around the northern Wolf and Darwin islands while minimizing its effects on the marine economy of the people of the area. [3] The project uses a variety of mapping techniques to identify areas of damaged coral. It also educates the fishing and tourism industries on ways to cause less damage to the reefs. [3]

With the help of these conservation efforts and increased awareness, coral reefs in the Galapagos have a more promising chance of recovery. I will definitely be checking up on the Galapagos reefs in the future.

Sources:

[1] Correa, Adrienne, et al. “Rapid recovery of a coral reef at Darwin Island, Galapagos Islands.” Galapagos Research 66 (2009): 6.

[2] Duff, Andrew. “Guarding the Fragile Reefs in Galapagos.” Earth and Environment. Futurity, 12 July 2010. Web. <http://www.futurity.org/guarding-the-fragile-reefs-in-galapagos/>.

[3] “International Help for the Galapagos Coral Reefs.” European Commission : CORDIS : News and Events : International Help for the Galapagos Coral Reefs. University of Southampton, 5 Aug. 2009. Web. <http://cordis.europa.eu/news/rcn/31107_en.html>.

[4] “The Galápagos Islands: A Glimpse into the Future of Our Oceans.” NOAA AOML, 2006. Web. <http://www.aoml.noaa.gov/keynotes/keynotes_0115_galapagos.html>.

[5] Simoes Correa, Adrienne. “Symbiodinium Bleaching.” Coral Reef Ecosystems. Texas, Houston. 14 Apr. 2016. Lecture.

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Thermal Stress Hitting Abrolhos: How Is The Future Looking?

Posted on April 18, 2016 by pb21

Over the last month, newspapers have been flooded with information about coral bleaching – what is great to raise global awareness about this very serious problem affecting such an iconic ecosystem. However, the reason this has happened is really sad: the great barrier reef has succumbed to the third global coral bleaching event, and has been affected very intensely. About 95% of reefs are severely bleached, and mortality of up to 50% has already been reported (1). This shows us that the third Global bleaching event is a serious treat, and certainly is not over yet.

The reef area we have been monitoring since February – the Abrolhos marine national park – has been suffering the consequences of the El-Niño on the last month, and has already been through 2 Degree-heating weeks (Figure 1). A degree heating week is one degree Celsius above the local mean summer temperature, what for corals means temperature stress and, possibly, bleaching. In the last 3 years, Abrolhos has consistently faced 1 degree-heating week during the summer (Figure 1), and fortunately no bleaching has been reported. However, it is clear that the current stress had an earlier onset, in addition to being the biggest in the last couple years, and , of course, it is not nearly over yet. In the last couple years, Abrolhos has been relatively resistant to Bleaching. The last relevant event of the type described in the literature dates to 2007 and 2008 (2), but since then, a happy no bleaching gap of 8 years has persisted.

vs_ts_multiyr_abrolhos_reefs

Figure 1: NOAA Multi-Year Graph for mean temperature records and Degree Heating Weeks (DHW) accumulation in Abrolhos (2013-2016). Note that current stress (black line) is the biggest among all included years. Figure adapted from (5)

NOAA predictions though (Figure 2) show that the heat wave is not near to an end yet, as in the next 4 weeks we should see a continuation of the unusual heating. For weeks five to twelve, as the fall goes on in the south hemisphere, the thermal anomaly over Abrolhos is predicted to form a discontinuous with other heating in South Atlantic, resulting in a hot spot, that is, a point in the ocean where the temperature is higher than anywhere around it. With that, it is possible that Abrolhos will face a Bleaching Alert in the near future as the degree heating weeks accumulate, and it is possible that the no-bleaching 8 year gap could be over.

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Figure 2: NOAA Satellite Coral Bleaching Alert Area and Outlook for Abrolhos Reefs. In upper left, Abrolhos is delimited by Black line. Note that the area is subject to stress in the next 3 months, with the appearance of a hot spot over the Abrolhos region. Figure adapted from (6).

Brazil has been going through a very serious economic and political crisis (3), that virtually ceased the transfer of money to public research in the country, having a deep effect on scientific production (4). Fortunately, given the conservation relevance of Abrolhos, there is great interest in the region, and besides this unfavorable context, researchers in the Federal University of Bahia (UFBA) have monitored the reefs in the area during the last week of March. As of the date of writing of this post, their results have not been published yet, and further educational and scientific material resultant of their field campaign will soon be publicly available.

For the future, because Abrolhos is an effective national park, we expect that the local pressures on the reef, such as over-fishing and nutrient overload, will be maintained over control when compared to other unprotected areas. In that context, it is likely that the Abrolhos reef will be more severely affected by global –rather than local- changes. However, there is the description on the literature of a disease outbreak (7) that coincided with the last bleaching outbreak described for the area in 2007-2008. Since both events are related with thermal anomalies, the status of diseases as local factors is uncertain, and it is possible that bleaching and diseases act together to threat the reefs in the region. Additional stress is imposed by another global, climate-change related, factor: the increased CO2 dissolved in the water. The South Atlantic is currently affected by this, and is also likely to be affected further in the future as the problem gets worse (8).

Given NOAA predictions (Figure 2), and all the global threats for the global reefs in the future, we cannot predict a certain brilliant future for the ecosystem in the South Atlantic. However, we can still look forward to the results to be published in the near future by UFBA researchers, and hope that Abrolhos heroically resists the stresses, contributing to the conservation of South Atlantic reefs. Go, Abrolhos!

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References:

(1) “Australia’s Great Barrier Reef hit by ‘worst’ bleaching” http://www.bbc.com/news/world-australia-35914009 , accessed in 17/4/2016

(2)Sassi, R., Costa Sassi, C. F., Gorlach-Lira, K., & Fitt, W. K. (2015). Pigmentation changes in Siderastrea spp. during bleaching events in the costal reefs of northeastern Brazil., 43(1), 176–185. http://doi.org/10.3856/vol43-issue1-fulltext-15

(3) de Carvalho, F. J. C. (2016). Looking Into the Abyss? Brazil at the Mid-2010s(No. wp_860).

(4) Gibney, E. (2015). Brazilian science paralyzed by economic slump. Nature,526(7571), 16.

(5) http://coralreefwatch.noaa.gov/vs/ts_figures/ts_multi_year/vs_ts_multiyr_abrolhos_reefs.png, accessed in 17/4/2016

(6) http://coralreefwatch.noaa.gov/vs/gauges/abrolhos_reefs.php, accessed in 17/4/2016

(7) Francini-Filho, R. B., Moura, R. L., Thompson, F. L., Reis, R. M., Kaufman, L., Kikuchi, R. K., & Leão, Z. M. (2008). Diseases leading to accelerated decline of reef corals in the largest South Atlantic reef complex (Abrolhos Bank, eastern Brazil). Marine Pollution Bulletin, 56(5), 1008-1014.

(8) Kerr, R., da Cunha, L. C., Kikuchi, R. K., Horta, P. A., Ito, R. G., Müller, M. N., … & Pinheiro, B. R. (2015). The western south Atlantic Ocean in a high-CO2 world: current measurement capabilities and perspectives. Environmental management, 1-13.

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A Look Forward: How Will Kiribati Fair?

Posted on April 18, 2016 by akw6

Welcome to my last entry on the coral reef of the island nation of Kiribati. Previously, we have discussed current state and recent changes. In this entry, we will focus on the future of this delicate ecosystem.

We look to the future of coral reefs as the benchmark for the rest of our global ecosystem. To those that argue against the prioritization of climate change on governmental agendas, the extreme changes that we are seeing in coral reefs is the exact reason why we must do so. If these areas are facing drastic changes and die offs, we must take this to mean that large scale negative change is imminent for many other ecosystems across the world. If action is not taken, we may find ourselves facing ecological changes with dire economic consequences.

Figure 1. Historical photographs document decline in fish catch size with corals (Key West).

Figure 1. Historical photographs document decline in fish catch size with corals in Key West (6).

According to the Office of the President (Republic of Kiribati), the country’s scientists have  been finding compelling evidence that climate change will move in such a direction so as to have a negative impact on their surrounding coral reefs. They have listed six major climate changes: continued increased temperature, increased ‘hot days’, changing rainfall patterns (less droughts), more extreme rainfall days, continued rising sea levels, and increasing ocean acidification. Each one of these climatic changes has the potential to negatively impact reefs (2).

Figure 1. Fish swim over a wasteland of dead coral.

Figure 2. Fish swim over a wasteland of dead coral in Kiribati (5).

Increasing temperature will push corals outside of their thermotolerance range, thus rendering their biological mechanisms unable to function. Toxic oxygen radicals are produced when coral tissue is put under such stress. This may additionally lead to bleaching. Increased rainfall may expose corals to lower levels of salinity. This is consequence to corals as they are osmoconformers, meaning they take on the same salinity level as the surrounding environment. Lower salinity would cause the swelling of coral tissue, causing damage. This damage may then interrupt the photosynthetic capabilities of the tissue. Ocean acidification, or an overall lowering of the pH of the ocean has its own negative impact on corals. High levels of CO2 create conditions which go on to inhibit the ability of corals to build their skeletons and for larva to settle on a substrate (4). Not only is each one of these changing abiotic factors going to negatively effect coral reefs in Kiribati and cause bleaching, but they are all also happening at the same time (3).

For Kiribati, this means a dangerous future. As previously mentioned, the President has made plans to fortify some of the islands as well as purchasing alternative land. This plan may become necessary quicker than expected. Predictions currently indicate that the effect of global warming may make the island nation uninhabitable even before the predicted ocean level rise encroaches into the island’s territory. Some have said that by the year 2080, the risk of flood in the Pacific atolls will have increased by 200 fold (1). Not only is this level change expected to have drastic impacts, but the addition of the associated loss of coral reef makes the threat of storm damage much stronger. All together, it seems that Kiribati made the correct choice in creating a Plan B. While there may be some signs of hope for individual areas, the overall picture of the reef system is not a good one. Additionally, the technologically complex interventions that are necessary to save this ecosystem are extremely expensive. This may prevent the nation of Kiribati from even beginning to rectify the damage done. We may see terrible decimation by the bleaching event/stressful abiotic factors before things improve in Kiribati and the globe.

Resources

“Rising Sea Level in the Republic of Kiribati | Global Warming Effects.” Climate Hot Map. Web. 18 Apr. 2016. <http://www.climatehotmap.org/global-warming-locations/republic-of-kiribati.html>.

“Climate Change.” Climate Change. Nation of Kiribati. Web. 18 Apr. 2016. <http://www.climate.gov.ki/future-climate/>.

Sheppard, Charles, Simon K. Davy, and Graham M. Pilling. The Biology of Coral Reefs. Oxford: Oxford UP, 2009. Print.

“The Effects of Ocean Acidification on Coral Reefs.” Climate Interpreter. Web. 18 Apr. 2016. <http://climateinterpreter.org/content/effects-ocean-acidification-coral-reefs>.

Dead Coral. Digital image. National Geographic. Web. 17 Apr. 2016. <https://natgeoeducationblog.files.wordpress.com/2014/03/coral-bleaching.jpg>.

Simoes Correa, Adrienne. “Corals in the Modern World.” Coral Reef Ecosystems. Texas, Houston. 5 Apr. 2016. Lecture.

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Bleaching Stress Ramps up in American Samoa, yet Situation Looks Better than 2015

Posted on April 17, 2016 by jwh11

Coral reefs in American Samoa had a tough year in 2015. That year, bleaching due to high water temperatures led to widespread death of corals, reaching 80% on some reefs [1]. Reefs in the region experienced bleaching-inducing temperatures all the way from January to June, with the worst stress taking place from late February to the end of April. From mid March to late April, stressed exceeded eight degree heating weeks (DHW), with a peak of eleven DHW at the end of March [2]. The bleaching itself was observed as early as February [1].

airportreef-smallBleaching in 2015 led to the deaths of many corals on American Samoan Reefs, such as the one seen here. From http://www.globalcoralbleaching.org/

This year, temperature stress has been much milder. Though we are yet to see what will happen when temperatures are at their worst in late April, 2016 had a much milder February and March compared to the year before [2]. While the intensity may be less and the buildup certainly slower, the worst is still yet to come. The Samoas are already in Alert Level 1, according to NOAA’s Coral Reef Watch, and the entire region is expected to be under Alert Level 2 for the next month, after which the high temperatures will subside, save for the area north of the islands, where Pukapuka and Tokelau will experience critical bleaching stress for the next few months [2]. Whether or not we get a repeat of the mass death seen in 2015 is still up in the air.

Screen Shot 2016-04-17 at 6.38.00 PM

Data from NOAA’s Coral Reef Watch indicates the next several weeks will be the worst for the Samoan region. From http://coralreefwatch.noaa.gov/vs/gauges/samoas.php

Another factor at play, other than the lower sea temperatures compared to last year, is the resiliency of the corals themselves. A 2014 study found that Acropora hyacinthus on the reefs of Ofu in American Samoa showed that the coral was employing roughly equal parts genetic adaptation and physiological acclimatization to deal with increased temperatures [3]. Whether or not this is enough to significantly stave off future bleaching events, or if other corals are as resilient, is still unknown [4].

1.) Global Coral Bleaching. Underwater Earth, 2015. Web. <http://www.globalcoralbleaching.org/>.

2.) “Samoas 5-km Bleaching Thermal Stress Gauges.” NOAA Coral Reef Watch. US Department of Commerce, 16 Apr. 2016. <http://coralreefwatch.noaa.gov/vs/gauges/samoas.php>.

3.) Mascarelli, Amanda. “Corals Use Multiple Tricks to Adapt to Hotter Seas.”Nature.com. Nature Publishing Group, 24 Apr. 2014. Web. <http://www.nature.com/news/corals-use-multiple-tricks-to-adapt-to-hotter-seas-1.15104>.

4.) Palumbi, Stephen R., Daniel J. Barshis, Nikki Taylor-Knowles, and Rachael A. Bay. “Mechanisms of Reef Coral Resistance to Future Climate Change.”Science 344.6186 (2014): 895-98. Sciencemag.org. American Association for the Advancement of Science, 23 May 2014. Web. <http://science.sciencemag.org/content/344/6186/895>.

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Update: The Islands of Kiribati in the Danger Zone

Posted on March 17, 2016 by akw6

Hello and welcome back to my blog about the global bleaching event in the Islands of Kiribati!

While it is difficult to determine the exact changes in the abiotic and biotic factors that are surrounding the Islands of Kiribati, some very interesting things have changed in regard to the political environment. Kiribati’s president (Anote Tong) has come up with a two-fold plan to ensure his countries safety. First, he has plans to physically fortify at least on the islands within the chain. As of 2015, he has been meeting with companies from Japan and the Netherlands to find the proper technology to ensure the nation’s survival. However, the President is also showing foresight in that he is not completely investing in the idea of the physical island’s survival. This manifests itself in the second part of the plan, which is a purchase of 5,000 acres of land in the neighboring nation of Fiji. He has also been involved in talks with other nations to secure admittance for the possible migration of his people. If it must happen, Anote Tong says that it will be a “migration with dignity.(1)”

Figure 1. President Anote Tong of Kiribati

Figure 1. President Anote Tong of Kiribati (1).

On the environmental side, Kiribati may be seeing some of the effects of coral bleaching affect it in the most recent years. Though NOAA (2) predicted that it was in danger of bleaching in 2015, a 2014 article by the Guardian (3) separately reported the bleaching event was seriously effecting new areas in Kiribati. If this is true, by now, in 2016, the bleaching is likely to have been spreading throughout the region. Also in 2015, a group of scientists from the Georgia Institute of Technology found that 50-90% of coral in Kiribati had bleached (4), with 30% already dead. They attribute this to the warming effect of El Niño.  It seems that in the past year, the reefs surrounding the Island Nation of Kiribati has been increasingly stressed by a combination of climate change and El Niño. In the future, there may be increasing sea levels and temperatures. None of this bodes well for the reef ecosystem. If these factors continue to increase, Kiribati may have to do some serious thinking about how to preserve both their nation and their natural resources.

Figure 2. Aerial view of one of the islands of the nation of Kiribati.

Figure 2. Aerial view of one of the islands of the nation of Kiribati (5).

Overall, we may be seeing Kiribati enter a dangerous zone in regards to its reef ecosystems. There are no indications that these abiotic trends will reverse, thus leading to increasing sea levels, higher temperature, and more aggressive coral bleaching. Additionally, we as a society are struggling to contain our anthropogenic effects, adding to the precipitous situation that these reefs find them in. Add to that the future complex geopolitical situation that Kiribati finds itself in, and you have one large conundrum for the nation and the scientific community. Read the next blog post for more ideas about the future of Kiribati and how its corals will fare!

 

References

  1. Worland, J. (n.d.). Meet the President Trying to Save His Island Nation From Climate Change. Retrieved March 17, 2016, from http://time.com/4058851/kiribati-cliamte-change/
  2. NOAA declares third ever global coral bleaching event. (n.d.). Retrieved March 17, 2016, from http://www.noaanews.noaa.gov/stories2015/100815-noaa-declares-third-ever-global-coral-bleaching-event.html
  3. Mathiesen, K. (2014). Major coral bleaching in Pacific may become worst die-off in 20 years, say experts. Retrieved March 17, 2016, from http://www.theguardian.com/environment/2014/dec/19/major-coral-bleaching-pacific-may-worst-20-years
  4. Scientists In Kiribati Islands Observe 50% – 90% Of Corals Bleached; 30% Already Dead. (n.d.). Retrieved March 17, 2016, from http://www.democraticunderground.com/112794987

    Aerial Kiribati [Photograph]. (n.d.).

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Losing the Pristine: Coral Bleaching strikes in North Great Barrier Reef

Posted on March 17, 2016 by ams13

Unfortunately, the predictions raised in my blog post last month about the fate of the Great Barrier Reef (GBR) in response to the ongoing mass global bleaching event have come true. Throughout March, coral reefs located on the far north section of the GBR have suffered variable but widespread bleaching.

Map of the Great Barrier Reef. The area north of Cairns is currently experiencing moderate to severe bleaching.

Map of the Great Barrier Reef. The area north of Cairns is currently experiencing moderate to severe bleaching [4].

In particular, the area north of Cairns has been affected the most severely, such as Lizard Island.

Lizard Island is located by the red star in this map. It is located about 250 km NE of Cairns.

Lizard Island is located by the red star in this map. It is located about 250 km NE of Cairns [5].

Dr. Russell Reichlet, Chairman of the Great Barrier Reef Marine Park Authority (GBRMPA), says that surveys conducted in February indicate Sea Surface Temperatures as high as 33˚C in the area1. If you recall from my previous post, high temperatures are one of the primary contributors to coral bleaching. Dr. Reichlet also reported that there is severe bleaching on the inshore reefs and moderate bleaching on the mid-shelf reefs of this Lizard Island area. He also cites that reports of the mid-shelf and outer reefs surveyed further south showed only minor to moderate bleaching, which is typical during this time of the year for that area. The main concern is the north.

Photograph of Lizard Island. You can see the fringing reef bordering the island from above.

Photograph of Lizard Island. You can see the fringing reef bordering the island from above [6].

While coral bleaching in any case is a tragedy, it is especially devastating right now for Australia. The northern GBR has been established as the most pristine section of the entire 300 km (1800 miles) of coastline it covers. Due to it’s isolation up north, farther from the heavy tourism that hits the southern GBR, this area is home to previously very healthy reefs. In contrast, reports of high cloud cover and heavy rainfall have mitigated the effects of the bleaching event in the central and southern GBR1. These factors do so by keeping sea surface temperature (SST) down, thus providing some relief from the heat stresses that cause corals to bleach1.

It appears that right now the far north GBR is experiencing the worse part of the bleaching event. The National Oceanic and Atmospheric Administration (NOAA) uses satellites and modeling to create Regional Coral Bleaching Thermal Stress Gauges, which provide current and future predictions of the severity of bleaching in a given area2. The most recent data on the Far Northern GBR is pictured below.

Maps and gauges representing the severity of coral bleaching in Far Northern GBR. The Maps represent the current conditions (upper left), and projections for 1-4 weeks (upper right), 5-8 weeks (bottom left), and 9-12 weeks (bottom right) out.

Maps and gauges representing the severity of coral bleaching in Far Northern GBR. The Maps represent the current conditions (upper left), and projections for 1-4 weeks (upper right), 5-8 weeks (bottom left), and 9-12 weeks (bottom right) out [7].

The 4 maps show the current conditions and projections for 1-4, 5-8, and 9-12 weeks out. It is evident from this visual representation that the reef is undergoing the most severe bleaching currently. There are mixed levels of severity projected for the next 1- 4 weeks, with some areas still in Alert Levels 1 and 2, while the majority of the area appears to reduce to a Watch level. The purpose of these different levels are to assist the overseeing authorities of the reefs in how to respond to this event.

NOAA also utilized its data to create a timescale graph of the SST of the reef, pictured below.

Graph of the Sea Surface Temperatures (SST) (in Celsius) in the Far Northern GBR plotted against the months over the past two years. The current period (March) indicates above average values.

Graph of the Sea Surface Temperatures (SST) (in Celsius) in the Far Northern GBR plotted against the months over the past two years. The current period (March) indicates above average values [8].

It is apparent from this graph that the Far Northern GBR is currently exceeding its bleaching threshold SST, as well as its Maximum Monthly Mean SST and Monthly Mean Climatology.

While I have not been able to find any current research papers regarding what is happening, the World Wildlife Fund (WWF) in Australia posted a video and photographs on March 1st showing the current state of a reef on Lizard Island. These are included below.

Coral bleaching, Lizard Island, Great Barrier Reef, March 2016 © WWF-Australia

Coral bleaching, Lizard Island, Great Barrier Reef, March 2016
© WWF-Australia [9]

Fortunately, a National Coral Bleaching Taskforce composed of 10 research institutions and over 300 scientists has been established to coordinate research on this event3. Additionally, on March 14th the WWF-Australia called for an urgent federal funding of $1 million in order to monitor the bleaching in the Far Northern GBR. As mentioned above, this area is moderately isolated and thus requires significant effort to get scientists and divers to the area (hence the $1 million asking price).

Time will tell what happens next in the GBR. Hopefully, the bleaching will diminish over the next few weeks and more reports will be available quantifying the severity of damage in the northern reefs. Until then, stay tuned.

References:

  1. “Reef coral bleaching intensifies in far north.” Great Barrier Reef Marine Park Authority. N.p. 03 March 2016. Web. http://www.gbrmpa.gov.au/media-room/latest-news/coral-bleaching/2016/reef-coral-bleaching-intensifies-in-far-north
  2. “Far Northern GBR 5-km Bleaching Thermal Stress Gauges.” NOAA Satellite and Information Service Coral Reef Watch.p. 15 March 2016. Web. http://coralreefwatch.noaa.gov/vs/gauges/gbr_far_northern.php
  3. “Coral-List Great Barrier Reef bleaching update.” Hughes, Terry. N.p. 1 March 2016. Web. http://coral.aoml.noaa.gov/pipermail/coral-list/2016-March/016625.html

Images:

  1. Great Barrier Reef Basin. Image. Web. N.d. http://www.mappery.com/map-of/Great-Barrier-Reef-Basin-Map
  2. Lizard Island, Australia. Image. Vacationstogo. Web. 2016. http://www.vacationstogo.com/cruise_port/Lizard_Island__Australia.cfm
  3. Lizard Island. Photograph. LizardIsland. Web. 2012. http://www.lizardisland.com.au
  4. Far Northern GBR Satellite Coral Bleaching Alert Area and Outlook. Image. NOAA Satellite and Information Service Coral Reef Watch. 15 March 2016. Web. http://coralreefwatch.noaa.gov/vs/gauges/gbr_far_northern.php
  5. Far Northern GBR. Image. NOAA Satellite and Information Service Coral Reef Watch. 15 March 2016. Web. http://coralreefwatch.noaa.gov/vs/gauges/gbr_far_northern.php
  6. Coral Bleaching, Lizard Island, Great Barrier Reef. Photograph. WWF-Australia. Web. 1 March 2016. http://www.wwf.org.au/?15680/Worst-coral-bleaching-on-Lizard-Island-since-2002-a-cause-for-concern

Video:

  1. WWF-Australia. “Coral Bleaching, Lizard Island, Great Barrier Reef.” Video. Web. 1 March 2016. https://youtu.be/isRIlXNY1Jc?list=PLtVYm_50W1qdlMhnRumj9qPovRaGPE3C8
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