The 2022 summer marine heatwaves and coral bleaching in China's Greater Bay Area

Zhao, Yu; Chen, Mingru; Chung, Tsing; Chan, Leo Lai; Qiu, Jian‐Wen

doi:10.1016/j.marenvres.2023.106044

Cited by 9 publications

(4 citation statements)

References 57 publications

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“…However, local stressors can act synergistically with global climate change, which is expected to drive region‐wide increases in extreme heatwaves and rainfall events (Tan et al., 2022; Wang et al., 2021). While historically uncommon (Duprey et al., 2020), a recent extreme heating event triggered unprecedented coral bleaching throughout the region, which is often considered a thermal refugium (Zhao et al., 2023). Extreme rainfall events increase the delivery of terrestrial sediments, which constrain coral distributions (Goodkin et al., 2011), and nutrients, which are known to exacerbate coral bleaching and disease (Thurber et al., 2014).…”

Section: Discussionmentioning

confidence: 99%

Life goes on: Spatial heterogeneity promotes biodiversity in an urbanized coastal marine ecosystem

McIlroy,

Guibert,

Archana

et al. 2024

Global Change Biology

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Both human populations and marine biodiversity are concentrated along coastlines, with growing conservation interest in how these ecosystems can survive intense anthropogenic impacts. Tropical urban centres provide valuable research opportunities because these megacities are often adjacent to mega‐diverse coral reef systems. The Pearl River Delta is a prime exemplar, as it encompasses one of the most densely populated and impacted regions in the world and is located just northwest of the Coral Triangle. However, the spatial and taxonomic complexity of this biodiversity, most of which is small, cryptic in habitat and poorly known, make comparative analyses challenging. We deployed standardized settlement structures at seven sites differing in the intensity of human impacts and used COI metabarcoding to characterize benthic biodiversity, with a focus on metazoans. We found a total of 7184 OTUs, with an average of 665 OTUs per sampling unit; these numbers exceed those observed in many previous studies using comparable methods, despite the location of our study in an urbanized environment. Beta diversity was also high, with 52% of the OTUs found at just one site. As expected, we found that the sites close to point sources of pollution had substantially lower diversity (44% less) relative to sites bathed in less polluted oceanic waters. However, the polluted sites contributed substantially to the total animal diversity of the region, with 25% of all OTUs occurring only within polluted sites. Further analysis of Arthropoda, Annelida and Mollusca showed that phylogenetic clustering within a site was common, suggesting that environmental filtering reduced biodiversity to a subset of lineages present within the region, a pattern that was most pronounced in polluted sites and for the Arthropoda. The water quality gradients surrounding the PRD highlight the unique role of in situ studies for understanding the impacts of complex urbanization pressures on biodiversity.

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Section: Discussionmentioning

confidence: 99%

Life goes on: Spatial heterogeneity promotes biodiversity in an urbanized coastal marine ecosystem

McIlroy,

Guibert,

Archana

et al. 2024

Global Change Biology

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“…The mean intensity and maximum intensity of MHWs are significantly negatively related to water depth. In other words, the shallower the water depth, the greater the intensity of the MHW [14]. This explains that both the mean intensity and maximum intensity decrease sequentially in the following order: the Bohai Sea, Yellow Sea, East China Sea and the South China Sea.…”

Section: Comparison Of Spatial Mean Of Mean Intensity and Maximum Int...mentioning

confidence: 95%

“…In these two seas, the monthly frequency difference is more obvious than in the East and South China Seas. As for the most frequent months, the maximum frequency in the Bohai, Yellow and East China Seas basically occurs in July and August [14], while that in the South China Sea occurs in May and June. It is worth noting that the frequency in the Yellow Sea in August is 0.37 counts, the highest in all of offshore China.…”

Section: Comparison Of Spatial Mean Of Frequency In China's Seasmentioning

confidence: 99%

“…The mass die-off of Zhangzi Island scallops in Bohai Sea in 2017 was also mainly caused by a marine heatwave event [13]. In addition, marine heatwaves caused an unprecedented coral bleaching event [14] in the northern South China Sea (nSCS) in 2022. With the frequent occurrence of extreme marine heatwave events and their devastating impacts on the marine environment and ecology, along with natural resources, heatwaves in China's marginal seas have also attracted widespread attention from marine scientists.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Marine Heatwaves in China’s Coastal Seas and Adjacent Offshore Waters

Li,

Wan,

Liu

et al. 2023

Atmosphere

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Marine heatwaves (MHWs) are changing global ecosystems and bearing profound socio-economic impacts, yet our understanding of the spatial features, temporal evolution characteristics, and regional differences in China’s marginal seas remains insufficient. In this study, the spatio-temporal variation characteristics of the frequency, mean intensity, maximum intensity, cumulative intensity, duration and total days of MHWs are systematically analyzed based on daily sea surface temperature data from Operational Sea Surface Temperature and Ice Analysis (OSTIA) for the period of 1983–2020. The results show the following: The annual mean frequency of MHWs in China’s coastal seas is 1.4–4.6 counts per year and increases gradually from north to south. The annual mean of mean intensity, maximum intensity and cumulative intensity are, respectively, in the ranges of 0.3–2.9 °C, 0.4–3.7 °C and 3.9–41.7 °C days, all of which show a significant decreasing trend from north to south. The annual mean of duration and total days of MHWs are in the respective ranges 8.7–19.7 and 18.9–69.1 days. The annual mean of frequency, cumulative intensity, duration and total days all show a clear increasing trend, with respective linear increases of 1.03 counts, 3.57 °C days, and 1.98 and 17.58 days per decade. The annual means of the mean intensity and maximum intensity have no obvious upward trend, with the exceptions of the Bohai and Yellow Seas. Finally, MHWs were divided into the four categories of moderate, strong, severe and extreme, with the results showing that moderate ones account for more than 70% of all heatwave events, while strong, severe and extreme ones, respectively, account for about 25%, 2% and 0.02%.

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Local conditions modulated the effects of marine heatwaves on coral bleaching in subtropical Hong Kong waters

Chung,

Dellisanti,

Lai

et al. 2024

Coral Reefs

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A mass coral bleaching event occurred in the summer of 2022 in subtropical Hong Kong, driven by two marine heatwaves (MHWs) with high intensities of 1.56 and 0.86 °C above a mean climate condition, both MHWs 7 days with a short gap of 4 days during the strong La Niña year. A transect survey was conducted at nine study sites in three regions, which revealed widespread coral bleaching with bleached coral cover ranging from 2.4 to 70.3%. In situ environmental data revealed the presence of a thermocline and halocline. Local conditions, including depth and wave exposure, significantly influenced the bleaching response. Shallow-water (2–4 m) corals were primarily affected, particularly in sheltered and moderately sheltered sites that exhibited higher levels of bleached coral cover (42.97 ± 15.4% and 44.93 ± 29.4%, respectively) compared to the exposed sites (31.8 ± 5.2%). Bleaching in deep waters (4–6 m) was minimal, with only a few colonies of Goniopora at two of the three sheltered sites exhibiting bleaching (1.7 ± 1.5%). Heat stress resistance differed between coral genera. Recovery rate for four common coral genera is low for Acropora tumida. Additionally, a minor hypoxia event was found to cause mortality of non-coral benthos at a sheltered site (Sharp Island). These findings highlight the alarming impact of extreme heatwaves on subtropical coral communities and underscore the importance of monitoring coral bleaching.

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The 2022 summer marine heatwaves and coral bleaching in China's Greater Bay Area

Cited by 9 publications

References 57 publications

Life goes on: Spatial heterogeneity promotes biodiversity in an urbanized coastal marine ecosystem

Life goes on: Spatial heterogeneity promotes biodiversity in an urbanized coastal marine ecosystem

Analysis of Marine Heatwaves in China’s Coastal Seas and Adjacent Offshore Waters

Local conditions modulated the effects of marine heatwaves on coral bleaching in subtropical Hong Kong waters

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