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

Authors :
Chung, Tzu Hao
Dellisanti, Walter
Lai, Keng Po
Wu, Jiajun
Qiu, Jian-Wen
Chan, Leo Lai
Source :
Coral Reefs; Oct2024, Vol. 43 Issue 5, p1235-1247, 13p
Publication Year :
2024

Abstract

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. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
07224028
Volume :
43
Issue :
5
Database :
Complementary Index
Journal :
Coral Reefs
Publication Type :
Academic Journal
Accession number :
179739710
Full Text :
https://doi.org/10.1007/s00338-024-02533-5