A new, high-resolution global mass coral bleaching database

Abstract

Episodes of mass coral bleaching have been reported in recent decades and have raised concerns about the future of coral reefs on a warming planet. Despite the efforts to enhance and coordinate coral reef monitoring within and across countries, our knowledge of the geographic extent of mass coral bleaching over the past few decades is incomplete. Existing databases, like ReefBase, are limited by the voluntary nature of contributions, geographical biases in data collection, and the variations in the spatial scale of bleaching reports. In this study, we have developed the first-ever gridded, global-scale historical coral bleaching database. First, we conducted a targeted search for bleaching reports not included in ReefBase by personally contacting scientists and divers conducting monitoring in under-reported locations and by extracting data from the literature. This search increased the number of observed bleaching reports by 79%, from 4146 to 7429. Second, we employed spatial interpolation techniques to develop annual 0.04° × 0.04° latitude-longitude global maps of the probability that bleaching occurred for 1985 through 2010. Initial results indicate that the area of coral reefs with a more likely than not (>50%) or likely (>66%) probability of bleaching was eight times higher in the second half of the assessed time period, after the 1997/1998 El Niño. The results also indicate that annual maximum Degree Heating Weeks, a measure of thermal stress, for coral reefs with a high probability of bleaching increased over time. The database will help the scientific community more accurately assess the change in the frequency of mass coral bleaching events, validate methods of predicting mass coral bleaching, and test whether coral reefs are adjusting to rising ocean temperatures.

Nearshore corals on the Mesoamerican Barrier Reef System on pace to cease growing as soon as year 2110

“…Mass coral bleaching was documented in the Caribbean in 1997-1998, 2005, 2010, and 2014-2016 (see methods and Donner et al, 2017[52]). The skeletal extension data from the present study was evaluated to determine whether recent mass bleaching events in the Caribbean Sea impacted coral skeletal extension within each reef zone of the Belize MBRS[53].…”

Coral chimerism as an evolutionary rescue mechanism to mitigate global climate change impacts

“…The stressors also interfere with hermatypic corals' role as primary reef ecosystem engineers, reshaping coral reef communities due to physiological and ecological intolerance to the newly developing environmental conditions (Anlauf et al, 2011;Bruno & Selig, 2007;Palumbi, Barshis, Traylor-Knowles, & Bay, 2014). Increased anthropogenic and climate changes are trends expected to worsen (Rinkevich, 2015), an issue which receives substantial attention from scientists, conservationists, decision-making authorities and the public (Donner, Rickbeil, & Heron, 2017;Eddy et al, 2018;Liew et al, 2018).…”

Marine heatwaves reveal coral reef zones susceptible to bleaching in the Red Sea

“…Moreover, temperatures during La Niña, El Niño's cold counterpart, are now recorded to be as hot as temperatures during El Niño three decades ago (Hughes, Anderson, et al, 2018). It is estimated that the world's coral reefs have seen a resulting eightfold increase in bleaching events since the 1997/1998 El Niño (Donner, Rickbeil, & Heron, 2017).…”