Cell death and degeneration in the symbiotic dinoflagellates of the coral Stylophora pistillata during bleaching

Rising sea temperatures are increasing the incidences of mass coral bleaching (the dissociation of the coral–algal symbiosis) and coral mortality. In this study, the effects of bleaching (induced by elevated light and temperature) on the condition of symbiotic dinoflagellates (Symbiodinium sp.) within the tissue of the hard coral Stylophora pistillata (Esper) were assessed using a suite of techniques. Bleaching of S. pistillata was accompanied by declines in the maximum potential quantum yield of photosynthesis (Fv/Fm, measured using pulse amplitude modulated [PAM] fluorometry), an increase in the number of Sytox-green-stained algae (indicating compromised algal membrane integrity and cell death), an increase in 2’,7’-dichlorodihydrofluroscein diacetate (H2DCFDA)- stained algae (indicating increased oxidative stress), as well as ultrastructural changes (vacuolisation, losses of chlorophyll, and an increase in accumulation bodies). Algae expelled from S. pistillata exhibited a complete disorganisation of cellular contents; expelled cells contained only amorphous material. In situ samples taken during a natural mass coral bleaching event on the Great Barrier Reef in February 2002 also revealed a high number of Sytox-labelled algae cells in symbio. Dinoflagellate\ud degeneration during bleaching seems to be similar to the changes resulting from senescence-phase cell death in cultured algae. These data support a role for oxidative stress in the mechanism of coral bleaching and highlight the importance of algal degeneration during the bleaching of a reef coral

A global protocol for monitoring of coral bleaching

Coral bleaching and subsequent mortality represent a major threat to the future health and productivity of coral reefs. However a lack of reliable data on occurrence, severity and other characteristics of bleaching events hampers research on the causes and consequences of this important phenomenon. This article describes a global protocol for monitoring coral bleaching events, which addresses this problem and can be used by people with different levels of expertise and resources.Coral reefs, Bleaching, Mortality, Monitoring

The 27–year decline of coral cover on the Great Barrier Reef and its causes

This study investigates the spatial and temporal dynamics of coral cover, identifies the main drivers of coral mortality, and quantifies the rates of potential recovery of the Great Barrier Reef.The world’s coral reefs are being degraded, and the need to reduce local pressures to offset the effects of increasing global pressures is now widely recognized. This study investigates the spatial and temporal dynamics of coral cover, identifies the main drivers of coral mortality, and quantifies the rates of potential recovery of the Great Barrier Reef. Based on the world’s most extensive time series data on reef condition (2,258 surveys of 214 reefs over 1985–2012), we show amajor decline in coral cover from 28.0%to 13.8% (0.53%y−1), a loss of 50.7% of initial coral cover. Tropical cyclones, coral predation by crown-of-thorns starfish (COTS), and coral bleaching accounted for 48%, 42%,and 10%of the respective estimated losses,amounting to 3.38% y−1 mortality rate. Importantly, the relatively pristine northern region showed no overall decline. The estimated rate of increase in coral cover in the absence of cyclones, COTS, and bleaching was 2.85%y−1, demonstrating substantial capacity for recovery of reefs. In the absence of COTS, coral cover would increase at 0.89% y−1, despite ongoing losses due to cyclones and bleaching. Thus, reducing COTS populations, by improvingwater quality and developing alternative control measures, could prevent further coral decline and improve the outlook for the Great Barrier Reef. Such strategies can, however, only be successful if climatic conditions are stabilized, as losses due to bleaching and cyclones will otherwise increase. Image: Wibble_Roisin / flick

Caribbean Corals in Crisis: Record Thermal Stress, Bleaching, and Mortality in 2005

BACKGROUND. The rising temperature of the world's oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. METHODOLOGY/PRINCIPAL FINDINGS. Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. CONCLUSIONS/SIGNIFICANCE. Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.NOAA Coral Reef Conservation Progra

Caribbean Corals in Crisis: Record Thermal Stress, Bleaching, and Mortality in 2005

BACKGROUND The rising temperature of the world's oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. METHODOLOGY/PRINCIPAL FINDINGS Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. CONCLUSIONS/SIGNIFICANCE Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.This work was partially supported by salaries from the NOAA Coral Reef Conservation Program to the NOAA Coral Reef Conservation Program authors. NOAA provided funding to Caribbean ReefCheck investigators to undertake surveys of bleaching and mortality. Otherwise, no funding from outside authors' institutions was necessary for the undertaking of this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Resort Wear Design with Coral Bleaching as Inspiration and its Business Opportunities in Indonesia

Indonesia is an archipelago state that has a diverse natural wealth, one of which is coral reef. Indonesia is included in The Coral Triangle; the center of the world‟s coral reef biodiversity, together with Malaysia, Philippines, Papua New Guinea, Timor Leste and Solomon Island. However, 35.15% of coral reefs in Indonesia are in poor condition due to natural phenomena, as well as human activities. One of the main causes of damage to coral reefs is coral bleaching. The purpose of this research is to raise awareness of the damage to coral reefs that occur, especially coral bleaching, through fashion products. The visualization of coral bleaching can be achieved by ruffles, pleats, and tie dye techniques. The re-search method used is a qualitative form of observations on brand competitor, literature studies by reviewing various sources of information regarding coral bleaching, resor wear, and business opportunities in the Indonesian fashion industry, conducting survey to target market, then continued with direct experiments techniques used to achieve the texture, shape and character of the coral reefs affected by coral bleaching. The exploration results are implemented into resort wear fash-ion products with reference to the lifestyle of the target market of the product in order to have potential as one of the new business opportunities in the Indonesia‟s creative industry. Keywords Coral bleaching, tie dye, ruffles, pleats, resort-wea

A global protocol for monitoring of coral bleaching

Coral bleaching and subsequent mortality represent a major threat to the future health and productivity of coral reefs. However a lack of reliable data on occurrence, severity and other characteristics of bleaching events hampers research on the causes and consequences of this important phenomenon. This article describes a global protocol for monitoring coral bleaching events, which addresses this problem and can be used by people with different levels of expertise and resources

Borneo coral reefs subject to high sediment loads show evidence of resilience to various environmental stressors

For reefs in South East Asia the synergistic effects of rapid land development, insufficient environmental policies and a lack of enforcement has led to poor water quality and compromised coral health from increased sediment and pollution. Those inshore turbid coral reefs, subject to significant sediment inputs, may also inherit some resilience to the effects of thermal stress and coral bleaching. We studied the inshore turbid reefs near Miri, in northwest Borneo through a comprehensive assessment of coral cover and health in addition to quantifying sediment-related parameters. Although Miri’s Reefs had comparatively low coral species diversity, dominated by massive and encrusting forms of Diploastrea, Porites, Montipora, Favites, Dipsastrea and Pachyseris, they were characterized by a healthy cover ranging from 22 to 39%. We found a strong inshore to offshore gradient in hard coral cover, diversity and community composition as a direct result of spatial differences in sediment at distances <10 km. As well as distance to shore, we included other environmental variables like reef depth and sediment trap accumulation and particle size that explained 62.5% of variation in benthic composition among sites. Miri’s reefs showed little evidence of coral disease and relatively low prevalence of compromised health signs including bleaching (6.7%), bioerosion (6.6%), pigmentation response (2.2%), scars (1.1%) and excessive mucus production (0.5%). Tagged colonies of Diploastrea and Pachyseris suffering partial bleaching in 2016 had fully (90–100%) recovered the following year. There were, however, seasonal differences in bioerosion rates, which increased five-fold after the 2017 wet season. Differences in measures of coral physiology, like that of symbiont density and chlorophyll a for Montipora, Pachyseris and Acropora, were not detected among sites. We conclude that Miri’s reefs may be in a temporally stable state given minimal recently dead coral and a limited decline in coral cover over the last two decades. This study provides further evidence that turbid coral reefs exposed to seasonally elevated sediment loads can exhibit relatively high coral cover and be resilient to disease and elevated sea surface temperatures

A reef manager's guide to coral bleaching

Scientists agree that tropical seas will continue to warm over coming decades, increasing both the probability and severity of mass bleaching events8-11. These scenarios pose particular challenges to coral reef managers, not the least because the main cause of mass coral bleaching–anomalously warm sea temperatures–is largely beyond their control.Yet, managers can play a critical role in helping reefs survive the threat of coral bleaching. Managers are in a unique position to increase our understanding of the phenomenon of coral bleaching, to take meaningful action during a bleaching event, and to develop strategies to support the natural resilience of reefs in the face of long-term changes in climate. Because of increasingly strong collaborations between reef managers and scientists, strategies are being developed to directly address the threat of coral bleaching. Management needs and preliminary strategies were first documented in 2000, when the IUCN published Management of Bleached and Severely Damaged Coral Reefs12. In 2002, the US Coral Reef Task Force called for a collaborative effort to identify actions local managers could take to address the impacts of climate change and mass bleaching on coral reefs. In response, three US government agencies (the National Oceanic and Atmospheric Administration, Environmental Protection Agency, and the Department of the Interior) convened an international workshop entitled 'Coral Reefs, Climate Change and Coral Bleaching' in June 2003. This workshop significantly advanced thinking about the strategies that could support managers in their efforts to respond to coral bleaching