For reef framework to persist, calcium carbonate production by corals and other calcifiers needs to outpace loss due to physical, chemical, and biological erosion. This balance is both delicate and dynamic and is currently threatened by the effects of ocean warming and acidification. Although the protection and recovery of ecosystem functions are at the center of most restoration and conservation programs, decision makers are limited by the lack of predictive tools to forecast habitat persistence under different emission scenarios. To address this, we developed a modelling approach, based on carbonate budgets, that ties species-specific responses to site-specific global change using the latest generation of climate models projections (CMIP6). We applied this model to Cheeca Rocks...

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The post New study establishes monitoring framework for evaluating reef persistence under climate change and ocean acidification appeared first on NOAA's Atlantic Oceanographic and Meteorological Laboratory.

Given that global warming is the greatest threat to coral reefs, coral restoration projects have expanded worldwide with the goal of replenishing habitats whose reef-building corals succumbed to various stressors. In many cases, however, these efforts will be futile if outplanted corals are unable to withstand warmer oceans and an increased frequency of extreme temperature events. Stress-hardening is one approach proposed to increase the thermal tolerance of coral genotypes currently grown for restoration. Previous studies have shown that corals from environments with natural temperature variability experience less bleaching when exposed to thermal stress, though it remains unclear if this localized acclimatization or adaptation to variable temperatures can be operationalized for enhancing restoration efforts...

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The post Pre-exposure to a variable temperature treatment improves the response of Acropora cervicornis to acute thermal stress appeared first on NOAA's Atlantic Oceanographic and Meteorological Laboratory.

Abstract: Naturally acidified environments, such as those caused by volcanic CO₂ venting, reveal how complex coral reef ecosystems may respond to future ocean acidification conditions. Few of these sites have been described worldwide, and only a single such site is known from the Caribbean. Herein, we have characterized an area of volcanic acidification at Mayreau Island, St. Vincent and the Grenadines. Despite localized CO₂ enrichment and gas venting, the surrounding area has high hard and soft coral cover, as well as extensive carbonate frameworks. Twice daily extremes in acidification, in some cases leading to undersaturation of aragonite, are correlated with tidal fluctuations and are likely related to water flow. Corals persisting despite this periodic acidification can provide insights into mechanisms of resilience and the importance of natural pH variability on coral reefs.

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The post Coral persistence despite extreme periodic pH fluctuations at a volcanically acidified Caribbean reef appeared first on NOAA's Atlantic Oceanographic and Meteorological Laboratory.