Reef location has a greater impact than coral bleaching severity on the microbiome of Pocillopora acuta

Coral Reefs - Coral reefs are increasingly threatened by heat stress events leading to coral bleaching. In 2016, a mass bleaching event affected large parts of the Great Barrier Reef (GBR). Whilst...     

The impact of ENSO on coral heat stress in the western equatorial Pacific

The Coral Triangle encompasses an extensive region of coral reefs in the western tropical Pacific with marine resources that support millions of people. As in all other reef regions, coral reefs in the Coral Triangle have been impacted by anomalously high ocean temperature. The vast majority of bleaching observations to date have been associated with the 1998 La Niña phase of ENSO. To understand the significance of ENSO and other climatic oscillations to heat stress in the Coral Triangle, we use a 5‐km resolution Regional Ocean Model System for the Coral Triangle (CT‐ROMS) to study ocean temperature thresholds and variability for the 1960–2007 historical period. Heat‐stress events are more frequent during La Niña events, but occur under all climatic conditions, reflecting an overall warming trend since the 1970s. Mean sea surface temperature (SST) in the region increased an average of ~ 0.1 °C per decade over the time period, but with considerable spatial variability. The spatial patterns of SST and heat stress across the Coral Triangle reflect the complex bathymetry and oceanography. The patterns did not change significantly over time or with shifts in ENSO. Several regions experienced little to no heat stress over the entire period. Of particular interest to marine conservation are regions where there are few records of coral bleaching despite the presence of significant heat stress, such as in the Banda Sea. Although this may be due to under‐reporting of bleaching events, it may also be due to physical factors such as mixing and cloudiness, or biological factors that reduce sensitivity to heat stress.     

Effect of short-term subaerial exposure on the cauliflower coral,Pocillopora damicornis,during a simulated extreme low-tide event

Coral Reefs - There is increased interest in understanding how stress reduces coral resistance to disturbances and how acclimatization increases the ability of corals to resist future stress. Most...     

Sea-surface temperature and thermal stress in the Coral Triangle over the past two decades

Increasing ocean temperature has become one of the major concerns in recent times with reports of various related ecological impacts becoming commonplace. One of the more notable is the increased frequency of mass coral bleaching worldwide. This study focuses on the Coral Triangle region and utilizes the National Oceanic and Atmospheric Administration-Coral Reef Watch (NOAA-CRW) satellite-derived sea surface temperature (SST) and Degree Heating Weeks (DHW) products to investigate changes in the thermal regime of the Coral Triangle waters between 1985 and 2006. Results show an upward trend in SST during this period with an average rate of 0.2°C/decade. However, warming within this region is not uniform, and the waters of the northern and eastern parts of the Coral Triangle are warming fastest. Areas in the eastern part have experienced more thermal stress events, and these stress events appear to be more likely during a La Niña.     

Linear extension,skeletal density,and calcification rates of the blue coral Heliopora coerulea

Coral Reefs - The brooding reef-building octocoral Heliopora is widespread on Indo-West Pacific reefs and appears to be relatively resistant to thermal stress, which may enable it to persist...     

Abiotic and biotic controls on coral recovery 16 years after mass bleaching

Coral Reefs - As climate changes increase heat stress on tropical ecosystems, the long-term persistence of coral reefs requires rapid coral recovery following coral bleaching events. Using the...     

In situ and remotely sensed temperature comparisons on a Central Pacific atoll

Coral Reefs - Climate-induced warming events increasingly threaten coral reefs, heightening the need for accurate quantification of baseline temperatures and thermal stress in these ecosystems. To...     

Temporal and spatial variation in fatty acid composition in Acropora tenuis corals along water quality gradients on the Great Barrier Reef,Australia

Coral Reefs - Fatty acids (FA) play a vital role in coral physiology, metabolism and stress resistance. Optimal health requires a balance of fatty acids, and more specifically essential...     

Resolving the interactions of ocean acidification and temperature on coral calcification media pH

Coral Reefs - Ocean acidification typically reduces the calcification rates of massive Porites spp. corals, but increasing seawater temperatures (below the stress and bleaching threshold) can...     

Do some corals like it hot?

Global increases in sea temperatures threaten coral reef resilience because thermal stress can cause corals to bleach; that is, to lose their photosynthetic microalgal symbionts. Recent evidence suggests that some corals associate with genotypes of microalgae that resist future thermal stress, however, these genotypes might provide less energy for growth when thermal stresses are curtailed. Coral reef resilience depends on whether phenotypic and genotypic changes in host-symbiont associations can match projected increases in the frequency and severity of thermal stress, as well as on our ability to ameliorate continuing human impacts.     

When depth is no refuge: cumulative thermal stress increases with depth in Bocas del Toro,Panama

Coral reefs are increasingly affected by high-temperature stress events and associated bleaching. Monitoring and predicting these events have largely utilized sea surface temperature data, due to the convenience of using large-scale remotely sensed satellite measurements. However, coral bleaching has been observed to vary in severity throughout the water column, and variations in coral thermal stress across depths have not yet been well investigated. In this study, in situ water temperature data from 1999 to 2011 from three depths were used to calculate thermal stress on a coral reef in Bahia Almirante, Bocas del Toro, Panama, which was compared to satellite surface temperature data and thermal stress calculations for the same area and time period from the National Oceanic and Atmospheric Administration Coral Reef Watch Satellite Bleaching Alert system. The results show similar total cumulative annual thermal stress for both the surface and depth-stratified data, but with a striking difference in the distribution of that stress among the depth strata during different high-temperature events, with the greatest thermal stress unusually recorded at the deepest measured depth during the most severe bleaching event in 2005. Temperature records indicate that a strong density-driven temperature inversion may have formed in this location in that year, contributing to the persistence and intensity of bleaching disturbance at depth. These results indicate that depth may not provide a stress refuge from high water temperature events in some situations, and in this case, the water properties at depth appear to have contributed to greater coral bleaching at depth compared to near-surface locations. This case study demonstrates the importance of incorporating depth-stratified temperature monitoring and small-scale oceanographic and hydrologic data for understanding and predicting local reef responses to elevated water temperature events.     

Heat stress differentially impacts key calcification mechanisms in reef-building corals

Coral Reefs - Coral reefs are increasingly threatened by climate change, mass bleaching events and ocean acidification (OA). Coral calcification, a process that is critical to build and maintain...     

Ecological consequences of Stony Coral Tissue Loss Disease in the Turks and Caicos Islands

Coral Reefs - Coral reefs are suffering global declines due to climate change, natural disasters, pollution, and diseases. Coral disease events have increased in frequency and severity in the past...     

The reef building coral Stylophora pistillata uses stored carbohydrates to maintain ATP levels under thermal stress

Coral Reefs - Coral reefs are on the brink of collapse from global warming and associated coral bleaching. Coral bleaching is the loss of algal symbionts from the coral tissue. The reduction in...     

Larval connectivity across temperature gradients and its potential effect on heat tolerance in coral populations

Coral reefs are increasingly exposed to elevated temperatures that can cause coral bleaching and high levels of mortality of corals and associated organisms. The temperature threshold for coral bleaching depends on the acclimation and adaptation of corals to the local maximum temperature regime. However, because of larval dispersal, coral populations can receive larvae from corals that are adapted to very different temperature regimes. We combine an offline particle tracking routine with output from a high‐resolution physical oceanographic model to investigate whether connectivity of coral larvae between reefs of different thermal regimes could alter the thermal stress threshold of corals. Our results suggest that larval transport between reefs of widely varying temperatures is likely in the Coral Triangle and that accounting for this connectivity may be important in bleaching predictions. This has important implications in conservation planning, because connectivity may allow some reefs to have an inherited heat tolerance that is higher or lower than predicted based on local conditions alone.     

Developing best practices for the restoration of massive corals and the mitigation of predation impacts: influences of physical protection,colony size,and genotype on outplant mortality

Coral Reefs - Coral reefs have undergone drastic declines due to anthropogenic and natural disturbances. In response, restoration efforts were developed to recover lost ecosystem services....     

Reefs from space: Satellite imagery,marine ecology,and ethnography in the Dominican Republic

Coral reef bleaching is an obvious indication that coastal marine ecosystems are being stressed. However, bleached reefs alone are poor indicators because they reflect the final stages of stress. This research project used multidate satellite imagery to look for coral reef changes as indicators of stress. Findings suggest that (1) satellite imagery can be used to identify small-scale changes in coastal marine ecosystems, including coral reefs; (2) remote sensing, marine ecology, and ethnographic data can be integrated to suggest potential causes of coral reef stress; and (3) changes in reef, seagrass, and mangrove ecozones are more closely tied to fishing, tourism, and land use practices than to global warming.     

Three decades of recurrent declines and recoveries in corals belie ongoing change in fish assemblages

Coral Reefs - Coral reefs are increasingly being altered by a myriad of anthropogenic activities and natural disturbances. Long-term studies offer unique opportunities to understand how multiple...     

Variance of coral anti-pathogen defense in response to transplantation between coral- and macroalgal-dominated reefs

Coral Reefs - Coral reefs are undergoing precipitous decline due to coral bleaching and disease following warming events, with impacted reefs often shifting from coral to macroalgal dominance. We...     

Bioerosion of reef-building crustose coralline algae by endolithic invertebrates in an upwelling-influenced reef

Coral Reefs - Coral reef growth is primarily determined by constructive and bioerosive processes acting on key reef-building organisms. Among them, corals are major contributors to the construction...