Coral bleaching

Bleached corals
Healthy corals

Coral bleaching occurs when coral polyps expel their zooxanthellae, dinoflagellate algae that live inside of their tissues. Normally, coral polyps live in an endosymbiotic relationship with these algae. This relationship is crucial for the health of the coral as well as the entire coral reef ecosystem, as the algae provide up to 90% of the coral's energy.[1][2] Due to the massive amount of energy that corals receive from the zooxanthellae, the corals will continue to live for some time after bleaching but soon begin to starve.[2]

Above-average sea water temperatures caused by global warming is the leading cause of coral bleaching.[2] According to the United Nations Environment Programme, the longest recorded global bleaching events killed coral on an unexpected scale between the years 2014 and 2016. In 2016, bleaching of coral on the Great Barrier Reef killed between 29 and 50 percent of the reef's coral.[3][4][5] By 2017, the bleaching has extended into the central region of the reef.[6][7] The average interval between bleaching events has halved between 1980 and 2016.[8] The increase in instances of bleaching is troubling due to the entire ecosystems that rely on these corals and the many, many services that these ecosystems provide for human beings.[9]

Mechanism of Bleaching

Coral and microscopic algae have a symbiotic relationship. When water temperatures get too high, the algae leave the coral tissue and the coral begins to starve.

The corals that form the great reef ecosystems of tropical seas depend upon a symbiotic relationship with single-celled flagellate protozoa called zooxanthellae that live within their tissues and give the coral its coloration. In this symbiotic relationship, the algae are kept safe from predators and receive carbon dioxide and nitrogen from the coral, which the algae use for photosynthesis. The coral, in turn, receives the products of photosynthesis from the algae, which serves as a source of energy for the coral.[10]

During unfavorable environmental conditions, coral polyps expel their zooxanthellae in order to ensure their short-term survival. Since most corals get their pigments from their symbionts (the algae), the result is a lighter or completely white appearance, hence the term "bleached".[11]

Healthy coral at left and bleached, but still living, coral to right

Coral can survive short-term disturbances, but if the conditions that lead to the expulsion of the zooxanthellae persist, the coral's chances of survival diminish. [12] In order to recover from bleaching, the zooxanthellae have to re-enter the tissues of the coral polyps and begin photosynthesizing in order to sustain the coral as well as the ecosystem that depends on them.[13] If the coral polyps die of starvation after bleaching, they will decay. The hard coral species will then leave behind their calcium carbonate skeletons, which will soon then get covered in macroalgae, effectively blocking coral re-growth. Eventually, the coral skeletons will erode, causing the reef structure to collapse.[12]

There are several models that aim to explain the mechanism behind the expulsion of algae from their coral host during mass bleaching events caused by increased sea surface temperatures. One such model is the “Oxidative Theory of Coral Bleaching” which proposes that bleaching is a response of the coral and the algae to oxidative stress caused by increased sea surface temperatures and UV radiation. The heat and UV radiation stress causes the destabilization of key steps in the process of photosynthesis within the algae, causing increased production of reactive oxygen species (ROS). These ROS molecules then diffuse out of the algae cells and into the coral cells. Once inside of the coral cells, these molecules can build up in concentration and cause oxidative damage within the cells which then triggers the corals to expel the source of these oxidative molecules, the algae. [14]

Triggers

Coral bleaching may be caused by a number of factors. While localized triggers lead to localized bleaching, the large scale coral bleaching events of the recent years have been triggered by increased sea surface temperatures.[15] Coral reefs located in warm, shallow water with low water flow have been more affected than reefs located in areas with higher water flow.[16]

Some triggers

Bleached coral - partially overgrown with algae

Impacts of Triggers on Coral

The triggers listed above name some of the main reasons why healthy coral cover is on the decline. Each one of these has severe impacts on the health and survival of these endangered coral. The combination of these triggers is the main reason why corals are not able to recover from bleaching. Increased Water Temperature and Solar Irradiance The mechanism for these impacts is explained under Mechanism for Coral Bleaching

Increased Nutrients

Coral reefs survive much better when they are exposed to “nutrient deserts”. Total nutrient concentrations do not change much as water flows over the reef. The total nutrients concentrations that flow out of the reef generally equal the nutrients concentrations that flow in. The only difference is that the composition of the total concentration is different. This is attributed to the theory that reefs “tightly recycle nutrients” within the ecosystem (Wyatt et. al. 2013). Abundance of nutrients is not necessary for reef production and the reef does not use all excess nutrients is present. Therefore, the abundance of nutrients is often absorbed by other organisms that outcompete the coral. For example, in 2002 in Kaneohe Bay, Hawaii people pumped an exorbitant amount of nutrients in the form of sewage (7 million gal/day) into the bay. As a result, phytoplankton bloomed from increased nutrients. The phytoplankton then died after the excess nutrients were absorbed and sunk to the bottom of the bay. Bacteria flocked to decompose the excess phytoplankton and used up all the oxygen in the bottoms waters during the decomposition process. This created an anoxic environment, les oxygen environment, that killed everything else on the bay floor.

Increased Sedimentation

Additional sediment has been added to the ocean over the past few years due to increased runoff. As sediment is added to the water, it begins to accumulate and bury the corals in the sediment. This is detrimental because buried corals are unable to obtain the light they need for photosynthesis and survival.

African Dust

Dust storms from the Sahara Desert often blow dust over the equator that settles in the Caribbean. The dust carries fungal spores and bacteria. These spores and bacteria create disease that affect the healthy coral often severely damaging or killing the organism (Gringley, 2017). As world temperatures increase, land gets more dry and creates more dust, which brings more disease to the ocean. In addition, dust is full of iron, which is often a limiting nutrient in the ocean. When the dust settles with the iron in it, it allows the organisms that are iron deficient to bloom, block light, and create anoxic environments similar to the Kaneohe Bay example.

Sunscreen

Sunscreen contains an ingredient, oxybenzone, that blocks the UV rays from entering the water. This is detrimental to the corals as the zooxanthellae in their tissues need light to photosynthesis and create food to survive. In addition, oxybenzone also is toxic to young coral. Oxybenzone also damages coral DNA, inhibits its ability to reproduce, causes deformities in coral reefs, makes them more susceptible to bleaching, and initiates endocrine disruption (Nelson, 2018).

Ocean Acidification

The pH in ocean is decreasing because the excess carbon dioxide in the atmosphere is dissolving into the ocean. Increased carbon dioxide levels lowers the ocean’s pH which turns bicarbonate, a molecule corals need and use to create their skeletons, into carbonic acid which corals can not use to create their skeletons. With less bicarbonate in the water, it is harder for corals build skeletons which decreases their ability to recover from damage and disturbance. In addition, the increase in CO2 allows herbivore overfishing and nutrient enrichment to change coral-dominated ecosystems to algal-dominated ecosystems.[81] A recent study from the Atkinson Center for a Sustainable Future found that with the combination of oceanic acidification and increasing sea surface temperatures, it may become difficult for coral to survive in as little as 50 years.[79]

Tourism

Coral reefs in high tourist environments are often suseptible to touching, kicking, and breaking. People often stand on reefs which kill the coral polyps. Many shops often sell coral as suveniors due to their beautiful nature. In addition, high tourist destinations are also plauged with sunscreen “slicks” in the water.


Mass bleaching events

Bleached Acropora coral (foreground) and normal colony (background), Keppel Islands, Great Barrier Reef

Elevated sea water temperatures are the main cause of mass bleaching events.[37] Sixty major episodes of coral bleaching have occurred between 1979 and 1990. With only nine such events occurring between 1960 and 1979, there is a clear increase in the instances of such events.[38] In 2016, the longest coral bleaching event was recorded.[39] The longest and most destructive coral bleaching event ever recorded was due to the El Niño that occurred from 2014–2017. During this time, over 70% of the coral reefs around the world became damaged.[9]

There are a variety of factors that can influence the resilience of corals in the face of mass bleaching events. These factors include how well corals can resist bleaching, their ability to survive the expulsion of algae, and the ability of  the reef to recover after a bleaching event. Within these three main factors, there are many more variables that can affect corals’ resilience to bleaching including individual responses to heat and stress, the conditions of the localized environment of the coral, and the genetics of the coral as well as the algae itself.[40]

Scientists believe that the oldest known bleaching was that of the Late Devonian (Frasnian/Famennian), also triggered by the rise of sea surface temperatures. It resulted in the demise of the largest coral reefs in the Earth's history.[41]

In the 2012–2040 period, coral reefs are expected to experience more frequent bleaching events. The Intergovernmental Panel on Climate Change (IPCC) sees this as the greatest threat to the world's reef systems.[42][43][44][45]

Impacts on reefs worldwide

Two images of the Great Barrier Reef showing that the warmest water (top picture) coincides with the coral reefs (lower picture), setting up conditions that can cause coral bleaching

Pacific Ocean

Great Barrier Reef

The Great Barrier Reef along the coast of Australia experienced mass bleaching events in 1980, 1982, 1992, 1994, 1998, 2002, 2006, 2016 and 2017.[45][46] Some locations suffered severe damage, with up to 90% mortality.[47] The most widespread and intense events occurred in the summers of 1998 and 2002, with 42% and 54%, respectively, of reefs bleached to some extent, and 18% strongly bleached.[48][49] However, coral losses on the reef between 1995 and 2009 were largely offset by growth of new corals.[50] An overall analysis of coral loss found that coral populations on the Great Barrier Reef had declined by 50.7% from 1985 to 2012, but with only about 10% of that decline attributable to bleaching, and the remaining 90% caused about equally by tropical cyclones and by predation by crown-of-thorns starfishes.[51]

A global mass coral bleaching has been occurring since 2014 because of the highest-ever recorded temperatures plaguing oceans. These temperatures have caused the most severe and widespread coral bleaching ever recorded in the Great Barrier reef, with the most severe bleaching occurring near Port Douglas in 2016. In late November of 2016, surveys of 62 reefs showed that long term heat stress from climate change caused a 29% loss of shallow water coral. The highest coral death and reef habitat loss was inshore and mid-shelf reefs around Cape Grenville and Princess Charlotte Bay.[52] The IPCC's moderate warming scenarios (B1 to A1T, 2 °C by 2100, IPCC, 2007, Table SPM.3, p. 13[53]) forecast that corals on the Great Barrier Reef are very likely to regularly experience summer temperatures high enough to induce bleaching.[48]

Hawaii

Major bleaching occurred in Hawaiian coral reefs in 1996 and in 2002.[54] In 2014, biologists from the University of Queensland observed the first mass bleaching event in Hawaii, and attributed it to The Blob.[55] In 2014 and 2015, a survey in Hanauma Bay Nature Preserve on Oahu found 47% of the corals suffering from coral bleaching and close to 10% of the corals dying.[56]

Japan

According to a 2017 Japanese government report, almost 75% of Japan's largest coral reef in Okinawa has died from bleaching.[57]

Indian Ocean

Maldives

More than 60% of the coral in the Maldives has suffered from bleaching in 2016.[58]

Thailand

Thailand experienced a severe mass bleaching in 2010 which affected 70% of the coral in the Andaman Sea. Between 30% and 95% of the bleached coral died.[59]

Indonesia

In 2017, researchers worked to quantify the coral cover in reefs off of the Indonesian Islands of Saktu Island and Melinjo Island . They found that the quality of the reefs was “poor” and that the coral cover was 22.3% for Saktu Island and 22.2% for Melinjo Island. They also found a high rate of disease on these reefs.[60]

Atlantic Ocean

United States

In South Florida, a 2016 survey of large corals from Key Biscayne to Fort Lauderdale found that about 66% of the corals were dead or reduced to less than half of their live tissue.[61]

Belize

In some parts of Belize, up to 75% of corals were destroyed in 2000–2002 due to storms and human-induced stress.[62]

Caribbean

Hard coral cover on reefs in the Caribbean have declined by an estimated 80%, from an average of 50% cover in the 1970s to only about 10% cover in the early 2000s.[63] A 2013 study to follow up on a mass bleaching event in Tobago from 2010 showed that after only 1 year, the majority of the dominant species declined by about 62% while coral abundance declined by about 50%. However, between 2011 and 2013, coral cover increased for 10 of the 26 dominant species but declined for 5 other populations.[64]

Other areas

Coral in the south Red Sea does not bleach despite summer water temperatures up to 34 °C (93 °F).[65][66] Coral bleaching in the Red Sea is more common in the northern section of the reefs but the southern part of the reef has been plagued by Crown of thorns starfish, dynamite fishing and other human-induced impacts on the environment. In 1988 there was a massive bleaching event that affected the reefs in Saudi Arabia and in Sudan. The southern reefs were more resilient to this disturbance. In 2010, coral bleaching occurred once again in Saudi Arabia and Sudan, where corals experienced 10-11 degree heating weeks. A degree heating week is a method of measuring the effect of heat stress on corals in terms of temperature but also duration of those increased temperatures. During this time period, certain taxa experienced 80% to 100% of their colonies bleaching, while others showed, on average, 20% bleaching.[67][68]

Impacts, Recovery, and Monitoring

Recovery and macroalgal regime shifts

Corals are often able to return to their original, pre-bleached state after a bleaching event due to increased temperature.[90][91] Corals have shown to be especially resilient to short-term disturbances such as storm disturbance and crown of thorns starfish invasions.[90]

Otherwise, reef ecosystems can experience a  regime shift, where previously flourishing coral reefs are taken over by thick layers of macroalgae.[92] This inhibits further coral growth because the algae produces antifouling compounds to deter settlement and competes with corals for space and light. As a result, macroalgae forms stable communities that make it difficult for corals to grow again. Reefs will then be more susceptible to other issues, such as declining water quality and removal of herbivore fish because coral growth is weaker.[15]

Until recently, the factors mediating the recovery of coral reefs from bleaching were not well studied. Research by Graham et al.(2005) studied 21 reefs around Seychelles in the Indo-Pacific in order to document the long-term effects of coral bleaching.[91] After the loss of more than 90% of corals due to bleaching in 1998, around 50% of the reefs recovered and roughly 40% of the reefs experienced regime shifts to macroalgae dominated compositions.[91] After an assessment of factors influencing the probability of recovery, the study identified five major factors: density of juvenile corals, initial structural complexity, water depth, biomass of herbivorous fishes, and nutrient conditions on the reef.[91] Overall, resilience was seen most in coral reef systems that were structurally complex and in deeper water.[91]

The ecological roles and functional groups of species also play a role in the recovery of regime shifting potential in reef systems. Coral reefs are affected by bioeroding, scraping, and grazing fish species. Bioeroding species remove dead corals, scraping species remove algae and sediment to further future growth, grazing species remove algae.[96] The presence of each type of species can influence levels of coral recruitment which is an important part of coral recovery.[96]Lowered numbers of grazing species after coral bleaching in the Caribbean has been likened to sea-urchin-dominated systems which do not undergo regime shifts to fleshy macroalgae dominated conditions.[92]

There is always the possibility of unobservable changes, or cryptic losses of resilience, in a coral community's ability to perform ecological processes.[90][96]These cryptic losses can result in unforeseen regime changes or ecological flips.[90] More detailed methods for determining the health of coral reefs that take into account long-term changes to the coral ecosystems and better-informed conservation policies are necessary to protect coral reefs in the years to come.[90][91][94][96]

Other ecosystem effects

Corals form the backbone of the coral reef ecosystems that are found in warm, tropical waters. Due to a lack of nutrients, these oligotrophic waters would not be nearly as productive or diverse without corals. Since most of the primary production, and therefore the base of the food web, in these ecosystems stem from the symbiotic relationship between the corals and their symbiotic zooxanthellae, rising sea surface temperatures leading to increased instances of coral bleaching and mortality can affect ecosystems in a very drastic way.[11] Once zooxanthellae use energy from the sun to photosynthesize, the products of photosynthesis are then taken up by the corals for its own biological processes and growth.[10] This energy is then passed on to the rest of the food web when specialized coral-eating fish and invertebrates, called corallivores, consume the coral’s flesh. This relationship between corals and the ecosystem that relies on them makes coral bleaching an issue that could affect the structure of tropical ecosystems as we know them.[11]

That being said, fish species tend to fare better following short-term reef disturbance than coral species as corals show limited recovery and reef fish assemblages have shown little change.[90] However, fish assemblages in reefs that experience bleaching exhibit potentially damaging changes. One study by Bellwood et al. notes that while species richness, diversity, and abundance did not change, fish assemblages contained more generalist species and less coral dependent species.[90] Responses to coral bleaching are diverse between reef fish species, based on what resources are affected.[93] Rising sea temperature and coral bleaching do not directly impact adult fish mortality, but there are many indirect consequences of both.[93] Coral-associated fish populations tend to be in decline due to habitat loss; however, some herbivorous fish populations have seen a drastic increase due to the increase of macroalgae colonization on dead coral.[93]

Economic, political, and social impact

According to Brian Skoloff of The Christian Science Monitor, "If the reefs vanished, experts say, hunger, poverty and political instability could ensue."[66] Since countless sea life depend on the reefs for shelter and protection from predators, the extinction of the reefs would ultimately create a domino effectthat would trickle down to the many human societies that depend on those fish for food and livelihood.[67]

Coral reefs provide various ecosystem services, one of which is being a natural fishery, as many frequently consumed commercial fish spawn or live out their juvenile lives in coral reefs around the tropics.[68][69][70] Thus, reefs are a popular fishing site and are an important source of income for fishers, especially small, local fisheries.[70] As coral reef habitat decreases due to bleaching, reef associated fish populations also decrease, which affects fishing opportunities.[68] A model from one study by Speers et al. calculated direct losses to fisheries from decreased coral cover to be around $49 – $69 billion, if human societies continue to emit high levels of greenhouse gases.[68] But, these losses could be reduced for a consumer surplusbenefit of about $14 – $20 billion, if societies choose to emit a lower level of greenhouse gases.[68] These economic losses also have important political implications, as they fall disproportionately on developing countries where the reefs are located, namely in Southeast Asia and around the Indian Ocean.[68][70][71] It would cost more for countries in these areas to respond to coral reef loss as they would need to turn to different sources of income and food, in addition to losing other ecosystem services such as ecotourism.[69][71] A study completed by Chen et al. suggested that the commercial value of reefs decreases by almost 4% every time coral cover decreases by 1% because of losses in ecotourism and other potential outdoor recreational activities.[69]

Coral reefs also act as a protective barrier for coastlines by reducing wave impact, which decreases the potential for damage, erosion, and flooding by storms. This indirect cost, combined with the lost revenue in tourism, will result in economic effects.[9]

Cost benefit analysis of reducing loss of coral reefs

IIn 2010, the Convention on Biological Diversity's (CBD) Strategic Plan for Biodiversity 2011–2020 created twenty distinct targets for sustainable development for post-2015. Target 10 indicates the goal of minimizing "anthropogenic pressures on coral reefs".[69] Two programs were looked at, one that reduces coral reef loss by 50% that has a capital cost of $684 million and a recurrent cost of $81 million. The other program reduces coral reef loss by 80% and has a capital cost of $1,036 million with recurring costs of $130 million. CBD acknowledges that they may be underestimating the costs and resources needed to achieve this target due to lack of relevant data but nonetheless, the cost-benefit analysis shows that the benefits outweigh the costs by a great enough amount for both programs (Benefit Cost Ratio of 95.3 and 98.5) that "there is ample scope to increase outlays on coral protection and still achieve a benefit to cost ratio that is well over one."[69]

Monitoring reef sea surface temperature

The US National Oceanic and Atmospheric Administration (NOAA) monitors for bleaching "hot spots", areas where sea surface temperature rises 1 °C or more above the long-term monthly average. The "hot spots" are the location in which thermal stress is measured and ,with the development of Degree Heating Week (DHW), the coral reef's thermal stress is monitored.[70][71] Global coral bleaching is being detected earlier due to the satellite remote sensing the rise of sea temperatures.[70][72] It is necessary to monitor the high temperatures because coral bleaching events are affecting coral reef reproduction and normal growth capacity, as well as it weakening corals, eventually leading to their mortality.[72] This system detected the worldwide 1998 bleaching event,[73][74] that corresponded to the 1997–98 El Niño event.[75] Currently, 190 reef sites around the globe are monitored by the NOAA, and send alerts to research scientists and reef managers via NOAA Coral Reef Watch (CRW) website.[76] By monitoring the warming of sea temperatures, the early warnings of coral bleaching, alerts reef managers to prepare and draw awareness to future bleaching events.[76]

Coral adaptations to change

There are a couple of modes of adaptation by which corals are hoped to survive the global increases in sea surface temperature caused by climate change. For example, Berkelmans et al. (2006) looked at the genetics of the zooxanthellae associated with Acropora millepora in three different regions of the Great Barrier Reef and found that corals of that species in the warmer, inner reef had a different type of zooxanthellae than corals in the cooler, outer reefs. They also found that the type of zooxanthellae found in the inner reef corals were more resistant to heat stress and bleaching than the types found in the outer reef corals. In their experiment, they transplanted corals from the cooler reefs to the warmer, inner reefs and found that some corals were able to change their dominant type of zooxanthellae to withstand the increased temperatures. This was only possible, however, if the more resistant type of zooxanthellae was already present in the coral’s tissues and as such, corals that only contained the type of zooxanthellae found in cooler waters were unable to adapt to the warmer temperatures. This research highlights that changing zooxanthellae type or configuration can help corals to acclimatize to changes in temperature.[77]

Palumbi et al. (2014) have also found that corals themselves can acclimatize to increased temperatures, not just by changes in zooxanthellae types. They found that some corals off the coast of Ofu Island in the American Samoa experience high temperature variability as well as temperatures above the critical bleaching temperature on a daily basis during daytime low tides (HV group). There are also corals off the coast of this island that are located in a part of the reef with a much less variable daily change in temperature and they rarely experience temperatures high enough to induce bleaching (MV group). They took samples of Acropora hyacinthus coral from each location and transplanted them to the other location to see how they would respond. They found that MV group corals that were exposed to higher heat were able to acclimatize but did not acquire the same resistance to bleaching as the original HV group corals possessed.[78]

The researchers posited that the reasoning behind the MV corals being able to achieve similar resistance to original HV corals was due to a change in gene expression for genes involved in heat acclimation. This finding indicates that corals themselves are capable to adapting to change, regardless of their symbionts.[78]

The role of the microbiome

The coral’s microbiome is a community of bacterial organisms that live in close association with the coral and are involved with its biology. In 2017, Maren Ziegler et al. conducted a study where they found that coral microbiomes are different based on the thermal habitat they live in. In the experiment, the researchers exposed fragments of Acropora hyacinthus corals to environments with different ranges of temperature. One location had a moderately variable temperature range, and the second had a highly variable temperature range. They took corals from each location and replanted half in the same location and the other half were transplanted into the other location. They found that after 17 months, the transplanted corals’ microbiomes were indistinguishable from the corals that resided in their new location. Moreover, during a simulated bleaching event, they found that all corals and their associated microbiomes that lived in the highly variable location, even transplanted individuals, fared better during the simulated event than those in the moderately variable location. This result illustrates the fact that coral bleaching is a complex process and that many factors, including the composition of the microbiome, come into play in how well corals fare in the face of heat stress.[79]

See also

Notes

  1. ↑ Dove SG, Hoegh-Guldberg O (2006). "Coral bleaching can be caused by stress. The cell physiology of coral bleaching". In Ove Hoegh-Guldberg, Jonathan T. Phinney, William Skirving, Joanie Kleypas. Coral Reefs and Climate Change: Science and Management. [Washington]: American Geophysical Union. pp. 1–18. ISBN 978-0-87590-359-0.
  2. 1 2 3 "The Great Barrier Reef: a catastrophe laid bare". The Guardian. 6 June 2016.
  3. ↑ "Coral bleaching on Great Barrier Reef worse than expected, surveys show". The Guardian. 29 May 2017. Retrieved 29 May 2017.
  4. ↑ "The United Nations just released a warning that the Great Barrier Reef is dying". The Independent. 3 June 2017. Retrieved 11 June 2017.
  5. ↑ Hughes TP, Kerry JT, Álvarez-Noriega M, Álvarez-Romero JG, Anderson KD, Baird AH, et al. (March 2017). "Global warming and recurrent mass bleaching of corals". Nature. 543 (7645): 373–377. Bibcode:2017Natur.543..373H. doi:10.1038/nature21707. PMID 28300113.
  6. ↑ "Mass coral bleaching hits the Great Barrier Reef for the second year in a row". USA TODAY. 13 March 2017. Retrieved 14 March 2017.
  7. ↑ Galimberti, Katy (18 April 2017). "Portion of Great Barrier Reef hit with back-to-back coral bleaching has 'zero prospect for recovery'". AccuWeather.com. Retrieved 18 April 2017. When coral experiences abnormal conditions, it releases an algae called zooxanthellae. The loss of the colorful algae causes the coral to turn white.
  8. ↑ Hughes TP, Anderson KD, Connolly SR, Heron SF, Kerry JT, Lough JM, et al. (January 2018). "Spatial and temporal patterns of mass bleaching of corals in the Anthropocene". Science. 359 (6371): 80–83. Bibcode:2018Sci...359...80H. doi:10.1126/science.aan8048. PMID 29302011.
  9. 1 2 Albright R (December 2017). "Can We Save the Corals?". Scientific American. 318 (1): 42–49. Bibcode:2017SciAm.318a..42A. doi:10.1038/scientificamerican0118-42. PMID 29257818.
  10. 1 2 "Zooxanthellae... What's That?".
  11. 1 2 3 Hoegh-Guldberg, Ove (1999). "Climate change, coral bleaching and the future of the world's coral reefs". Marine and Freshwater Research. 50 (8): 839–66. doi:10.1071/MF99078.
  12. 1 2 Hoegh-Guldberg, Ove (1999). "Climate change, coral bleaching and the future of the world's coral reefs". CSIRO. 50: 839–866.
  13. ↑ Nir O, Gruber DF, Shemesh E, Glasser E, Tchernov D (15 January 2014). "Seasonal mesophotic coral bleaching of Stylophora pistillata in the Northern Red Sea". PLOS One. 9 (1): e84968. Bibcode:2014PLoSO...984968N. doi:10.1371/journal.pone.0084968. PMC 3893136. PMID 24454772.
  14. ↑ Downs, C.A; Fauth, John E; Halas, John C; Dustan, Phillip; Bemiss, John; Woodley, Cheryl M (August 2002). "Oxidative stress and seasonal coral bleaching". Free Radical Biology and Medicine. 33 (4): 533–543. doi:10.1016/s0891-5849(02)00907-3. ISSN 0891-5849.
  15. 1 2 Hoegh-Guldberg O, Mumby PJ, Hooten AJ, Steneck RS, Greenfield P, Gomez E, et al. (December 2007). "Coral reefs under rapid climate change and ocean acidification". Science. 318 (5857): 1737–42. Bibcode:2007Sci...318.1737H. CiteSeerX 10.1.1.702.1733. doi:10.1126/science.1152509. PMID 18079392.
  16. ↑ Baker A, Glynn P, Riegl B (2008). "Climate change and coral reef bleaching: An ecological assessment of long-term impacts, recovery trends and future outlook". Estuarine, Coastal and Shelf Science. 80 (4): 435–471. Bibcode:2008ECSS...80..435B. doi:10.1016/j.ecss.2008.09.003.
  17. ↑ "Reef 'at risk in climate change'" (Press release). The University of Queensland. 6 April 2007. Retrieved 2 August 2016.
  18. ↑ Anthony, K. 2007; Berkelmans
  19. ↑ Saxby T, Dennison WC, Hoegh-Guldberg O (2003). "Photosynthetic responses of the coral Montipora digitata to cold temperature stress". Marine Ecology Progress Series. 248: 85–97. Bibcode:2003MEPS..248...85S. doi:10.3354/meps248085.
  20. ↑ Marimuthu N, Jerald Wilson J, Vinithkumar NV, Kirubagaran R (9 November 2012). "Coral reef recovery status in south Andaman Islands after the bleaching event 2010". Journal of Ocean University of China. 12 (1): 91–96. Bibcode:2013JOUC...12...91M. doi:10.1007/s11802-013-2014-2.
  21. ↑ Douglas, A.E. (April 2003). "Coral bleaching––how and why?". Marine Pollution Bulletin. 46 (4): 385–392. doi:10.1016/s0025-326x(03)00037-7. ISSN 0025-326X.
  22. ↑ Rogers CS (1990). "Responses of coral reefs and reef organisms to sedimentation". Marine Ecology Progress Series. 62: 185–202. Bibcode:1990MEPS...62..185R. doi:10.3354/meps062185.
  23. ↑ Kushmaro A, Rosenberg E, Fine M, Loya Y (1997). "Bleaching of the coral Oculina patagonica by Vibrio AK-1". Marine Ecology Progress Series. 147: 159–65. Bibcode:1997MEPS..147..159K. doi:10.3354/meps147159.
  24. ↑ Hoegh-Guldberg O, Smith G (1989). "The effect of sudden changes in temperature, light and salinity on the population density and export of zooxanthellae from the reef corals Stylophora pistillata Esper and Seriatopora hystrix Dana". Journal of Experimental Marine Biology and Ecology. 129 (3): 279–303. doi:10.1016/0022-0981(89)90109-3.
  25. ↑ Jones RJ, Muller J, Haynes D, Schreiber U (2003). "Effects of herbicides diuron and atrazine on corals of the Great Barrier Reef, Australia". Marine Ecology Progress Series. 251: 153–167. Bibcode:2003MEPS..251..153J. doi:10.3354/meps251153.
  26. ↑ Anthony KR, Kerswell AP (2007). "Coral mortality following extreme low tides and high solar radiation". Marine Biology. 151 (5): 1623–31. doi:10.1007/s00227-006-0573-0.
  27. ↑ Jones RJ, Hoegh-Guldberg O (1999). "Effects of cyanide on coral photosynthesis:implications for identifying the cause of coral bleaching and for assessing the environmental effects of cyanide fishing". Marine Ecology Progress Series. 177: 83–91. Bibcode:1999MEPS..177...83J. doi:10.3354/meps177083.
  28. ↑ Glynn, Peter W. (June 1991). "Coral reef bleaching in the 1980s and possible connections with global warming". Trends in Ecology & Evolution. 6 (6): 175–179. doi:10.1016/0169-5347(91)90208-f. ISSN 0169-5347.
  29. ↑ U. S. Geological Survey. Coral Mortality and African Dust. Retrieved on 10 June 2007.
  30. ↑ "Protect Yourself, Protect The Reef! The impacts of sunscreens on our coral reefs" (PDF). U.S. National Park Service. Retrieved 1 July 2013.
  31. ↑ Than, Ker. "Swimmers' Sunscreen Killing Off Coral". National Geographic News. National Geographic News. Retrieved 29 January 2008.
  32. ↑ "Coral Reef Safe Sunscreen". badgerbalm.com.
  33. ↑ Danovaro R, Bongiorni L, Corinaldesi C, Giovannelli D, Damiani E, Astolfi P, Greci L, Pusceddu A (April 2008). "Sunscreens cause coral bleaching by promoting viral infections". Environmental Health Perspectives. 116 (4): 441–7. doi:10.1289/ehp.10966. PMC 2291018. PMID 18414624.
  34. ↑ Downs CA, Kramarsky-Winter E, Fauth JE, Segal R, Bronstein O, Jeger R, Lichtenfeld Y, Woodley CM, Pennington P, Kushmaro A, Loya Y (March 2014). "Toxicological effects of the sunscreen UV filter, benzophenone-2, on planulae and in vitro cells of the coral, Stylophora pistillata". Ecotoxicology. 23 (2): 175–91. doi:10.1007/s10646-013-1161-y. PMID 24352829.
  35. ↑ Anthony KR, Kline DI, Diaz-Pulido G, Dove S, Hoegh-Guldberg O (November 2008). "Ocean acidification causes bleaching and productivity loss in coral reef builders". Proceedings of the National Academy of Sciences of the United States of America. 105 (45): 17442–6. Bibcode:2008PNAS..10517442A. doi:10.1073/pnas.0804478105. PMC 2580748. PMID 18988740.
  36. ↑ "How Do Oil Spills Affect Coral Reefs?". response.restoration.noaa.gov. Retrieved 24 April 2018.
  37. ↑ Baker AC, Glynn PW, Riegl B (2008). "Climate change and coral reef bleaching: An ecological assessment of long-term impacts, recovery trends and future outlook". Estuarine, Coastal and Shelf Science. 80 (4): 435–71. Bibcode:2008ECSS...80..435B. doi:10.1016/j.ecss.2008.09.003.
  38. ↑ Huppert A, Stone L (September 1998). "Chaos in the Pacific's coral reef bleaching cycle". The American Naturalist. 152 (3): 447–59. doi:10.1086/286181. PMID 18811451.
  39. ↑ McDermott, Amy (22 June 2016). "Coral bleaching event is longest on record". Science News. Retrieved 25 July 2016.
  40. ↑ Marshall P, Schuttenberg H (2006). A Reef Manager's Guide to Coral Bleaching (PDF). Townsville, Australia: Great Barrier Reef Marine Park Authority. pp. 78–79. ISBN 978-1-876945-40-4.
  41. ↑ Zapalski MK, Nowicki J, Jakubowicz M, Berkowski B (2017). "Tabulate corals across the Frasnian/Famennian boundary: architectural turnover and its possible relation to ancient photosymbiosis". Palaeogeography, Palaeoclimatology, Palaeoecology. 487: 416–429. Bibcode:2017PPP...487..416Z. doi:10.1016/j.palaeo.2017.09.028.
  42. ↑ IPCC (2007). "Summary for policymakers" (PDF). In Parry ML, Canziani OF, Palutikof JP, van der Linden PJ, Hanson CE. Climate Change 2007: impacts, adaptation and vulnerability: contribution of Working Group II to the fourth assessment report of the Intergovernmental Panel on Climate Change. Cambridge, UK: Cambridge University Press. pp. 7–22. ISBN 978-0-521-70597-4.
  43. ↑ Fischlin A, Midgley GF, Price JT, Leemans R, Gopal B, Turley C, Rounsevell MD, Dube OP, Tarazona J, Velichko AA (2007). "Ch 4. Ecosystems, their properties, goods and services" (PDF). In Parry ML, Canziani OF, Palutikof JP, van der Linden PJ, Hanson CE. Climate Change 2007: impacts, adaptation and vulnerability: contribution of Working Group II to the fourth assessment report of the Intergovernmental Panel on Climate Change. Cambridge, UK: Cambridge University Press. pp. 211–72. ISBN 978-0-521-70597-4.
  44. ↑ Nicholls RJ, Wong PP, Burkett V, Codignotto J, Hay J, McLean R, Ragoonaden S, Woodroffe CD (2007). "Ch 6. Coastal systems and low-lying areas" (PDF). In Parry ML, Canziani OF, Palutikof JP, van der Linden PJ, Hanson CE. Climate Change 2007: impacts, adaptation and vulnerability: contribution of Working Group II to the fourth assessment report of the Intergovernmental Panel on Climate Change. Cambridge, UK: Cambridge University Press. pp. 315–57. ISBN 978-0-521-70597-4.
  45. 1 2 Hennessy K, Fitzharris B, Bates BC, Harvey N, Howden M, Hughes L, Salinger J, Warrick R (2007). "Ch 11. Australia and New Zealand" (PDF). In Parry ML, Canziani OF, Palutikof JP, van der Linden PJ, Hanson CE. Climate Change 2007: impacts, adaptation and vulnerability: contribution of Working Group II to the fourth assessment report of the Intergovernmental Panel on Climate Change. Cambridge, UK: Cambridge University Press. pp. 507–40. ISBN 978-0-521-70597-4.
  46. ↑ Plumer, Brad (31 March 2016). "The unprecedented coral bleaching disaster at the Great Barrier Reef, explained". Vox Energy & Environment.
  47. ↑ Johnson JE, Marshall PA (2007). Climate change and the Great Barrier Reef: a vulnerability assessment. Townsville, Qld.: Great Barrier Reef Marine Park Authority. ISBN 978-1-876945-61-9. Archived from the original on 25 January 2014.
  48. 1 2 Done T, Whetton P, Jones R, Berkelmans R, Lough J, Skirving W, Wooldridge S (2003). Global Climate Change and Coral Bleaching on the Great Barrier Reef (PDF). Queensland Government Department of Natural Resources and Mines. ISBN 978-0-642-32220-3. Archived from the original (PDF) on 27 September 2011.
  49. ↑ Berkelmans R, De'ath G, Kininmonth S, Skirving WJ (2004). "A comparison of the 1998 and 2002 coral bleaching events on the Great Barrier Reef: spatial correlation, patterns, and predictions". Coral Reefs. 23 (1): 74–83. doi:10.1007/s00338-003-0353-y.
  50. ↑ Osborne K, Dolman AM, Burgess SC, Johns KA (March 2011). "Disturbance and the dynamics of coral cover on the Great Barrier Reef (1995–2009)". PLOS One. 6 (3): e17516. Bibcode:2011PLoSO...617516O. doi:10.1371/journal.pone.0017516. PMC 3053361. PMID 21423742.
  51. ↑ De'ath G, Fabricius KE, Sweatman H, Puotinen M (October 2012). "The 27-year decline of coral cover on the Great Barrier Reef and its causes". Proceedings of the National Academy of Sciences of the United States of America. 109 (44): 17995–9. Bibcode:2012PNAS..10917995D. doi:10.1073/pnas.1208909109. PMC 3497744. PMID 23027961.
  52. ↑ Final Report: 2016 Coral Bleaching Event on Great Barrier Reef . Great Barrier Reef Marine Park Authority Townsville, 2017, pp. 24–24, Final Report: 2016 Coral Bleaching Event on Great Barrier Reef .
  53. ↑ IPCC (2007). "Summary for policymakers" (PDF). In Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, Miller HL. Climate change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK: Cambridge University Press. pp. 1–18.
  54. ↑ Hokiel, Paul J. "Climate Change and Hawaii's Coral Reefs" (PDF). Hawaii Coral Reef Monitoring and Assessment Program. US Fish and Wildlife Service.
  55. ↑ "Rapidly warming ocean a threat to Hawaiian coral reefs". The University of Queensland. 2015.
  56. ↑ "Corals in peril at a popular Hawaiian tourist destination due to global climate change". Retrieved 30 May 2017.
  57. ↑ McCurry, Justin (11 January 2017). "Almost 75% of Japan's biggest coral reef has died from bleaching, says report". The Guardian. Retrieved 30 May 2017.
  58. ↑ "More than 60% of Maldives' coral reefs hit by bleaching". The Guardian. 8 August 2016. Retrieved 31 May 2017.
  59. ↑ "As sea temperatures rise, Thailand sees coral bleeching". Bangkok Post. 25 December 2016.
  60. ↑ Shidqi, Rafid Arifuddin; Pamuji, Barkah; Sulistiantoro, Tito; Risza, Milyarni; Faozi, Arif Nur; Muhammad, Agni Noor; Muharam, Muhammad Rifat; Putri, Ersha Derystia; Hartini, Rachmawati (February 2018). "Coral health monitoring at Melinjo Island and Saktu Island: Influence from Jakarta Bay". Regional Studies in Marine Science. 18: 237–242. doi:10.1016/j.rsma.2017.02.004. ISSN 2352-4855.
  61. ↑ Fleshler, David (24 April 2016). "South Florida corals dying in "unprecedented" bleaching and disease". Sun-Sentinel.com.
  62. ↑ Wilkinson, Clive (2002). GCRMN: Global Coral Reef Monitoring Network, Status of Coral Reefs of the World: 2002. Australian Institute of Marine Science. pp. 303–325. ISSN 1447-6185.
  63. ↑ Smith JE, Brainard R, Carter A, Grillo S, Edwards C, Harris J, Lewis L, Obura D, Rohwer F, Sala E, Vroom PS, Sandin S (January 2016). "Re-evaluating the health of coral reef communities: baselines and evidence for human impacts across the central Pacific". Proceedings. Biological Sciences. 283 (1822): 20151985. doi:10.1098/rspb.2015.1985. PMC 4721084. PMID 26740615.
  64. ↑ Buglass S, Donner SD, Alemu I JB (March 2016). "A study on the recovery of Tobago's coral reefs following the 2010 mass bleaching event". Marine Pollution Bulletin. 104 (1–2): 198–206. doi:10.1016/j.marpolbul.2016.01.038. PMID 26856646.
  65. ↑ Gabriel D. Grinmsditch and Rodney V. Salm, Coral Reef Resilience and Resistance to Bleaching, "IUCN: The World Conservation Union", 2006
  66. ↑ Alevizon, William. "Red Sea Coral Reefs". Coral Reef Facts. Retrieved 27 February 2014.
  67. ↑ Riegl BM, Bruckner AW, Rowlands GP, Purkis SJ, Renaud P (31 May 2012). "Red Sea coral reef trajectories over 2 decades suggest increasing community homogenization and decline in coral size". PLOS One. 7 (5): e38396. Bibcode:2012PLoSO...738396R. doi:10.1371/journal.pone.0038396. PMC 3365012. PMID 22693620.
  68. ↑ Furby KA, Bouwmeester J, Berumen ML (4 January 2013). "Susceptibility of central Red Sea corals during a major bleaching event". Coral Reefs. 32 (2): 505–513. Bibcode:2013CorRe..32..505F. doi:10.1007/s00338-012-0998-5.
  69. 1 2 Markandya A (21 October 2014). "Benefits and Costs of the Biodiversity Targets for the Post-2015 Development Agenda" (PDF). Copenhagen Consensus Center.
  70. 1 2 Liu G, Strong AE, Skirving W (15 April 2003). "Remote sensing of sea surface temperatures during 2002 Barrier Reef coral bleaching". Eos, Transactions American Geophysical Union. 84 (15): 137–141. Bibcode:2003EOSTr..84..137L. doi:10.1029/2003EO150001.
  71. ↑ McClanahan TR, Ateweberhan M, Sebastián CR, Graham NJ, Wilson SK, Bruggemann JH, Guillaume MM (1 September 2007). "Predictability of coral bleaching from synoptic satellite and in situ temperature observations". Coral Reefs. 26 (3): 695–701. doi:10.1007/s00338-006-0193-7.
  72. 1 2 Liu, Gang & Strong, Alan & Skirving, William & Arzayus, Felipe. (2005). Overview of NOAA coral reef watch program's near-real time satellite global coral bleaching monitoring activities. Proc 10th Int Coral Reef Symp. 1. pp. 1783–1793.
  73. ↑ "NOAA Hotspots". coral.aoml.noaa.gov.
  74. ↑ "Pro-opinion of NOAA Hotspots".
  75. ↑ NOAA Coral Reef Watch. "Methodology, Product Description, and Data Availability of Coral Reef Watch Operational and Experimental Satellite Coral Bleaching Monitoring Products". NOAA. Retrieved 27 February 2014.
  76. 1 2 Maynard JA, Johnson JE, Marshall PA, Eakin CM, Goby G, Schuttenberg H, Spillman CM (July 2009). "A strategic framework for responding to coral bleaching events in a changing climate". Environmental Management. 44 (1): 1–11. Bibcode:2009EnMan..44....1M. doi:10.1007/s00267-009-9295-7. PMID 19434447.
  77. ↑ Berkelmans, Ray; Oppen, Madeleine J. H. van (2006-09-22). "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 of London B: Biological Sciences. 273 (1599): 2305–2312. doi:10.1098/rspb.2006.3567. ISSN 0962-8452. PMC 1636081. PMID 16928632.
  78. 1 2 Palumbi, Stephen R. (May 2014). "Mechanisms of reef coral resistance to future climate change" (PDF). Science: Research Reports. 344: 895–897.
  79. ↑ Ziegler, Maren; Seneca, Francois O.; Yum, Lauren K.; Palumbi, Stephen R.; Voolstra, Christian R. (2017-02-10). "Bacterial community dynamics are linked to patterns of coral heat tolerance". Nature Communications. 8: 14213. doi:10.1038/ncomms14213. ISSN 2041-1723. PMC 5309854. PMID 28186132.

References

  • Watson ME (2011). "Coral Reefs". In Allin CW. Encyclopedia of environmental issues. 1. Pasadena, Calif.: Salem Press. pp. 317–318. ISBN 978-1-58765-735-1.

Goodbody-Gringley, Gretchen. “Coral Reef Ecology.” 2017.

Nelson. “Protecting Our Coral Reefs & Banning Oxybenzone!” Surfrider Foundation, July 2018, www.surfrider.org/campaigns/protect-our-coral-reefs-ban-oxybenzone

Wyatt, Alex SJ, et al. "Particulate nutrient fluxes over a fringing coral reef: Source‐sink dynamics inferred from carbon to nitrogen ratios and stable isotopes." Limnology and Oceanography 58.1 (2013): 409-427.


https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.2013.58.1.0409

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.