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Turbidity buffers coral bleaching under extreme wind and rainfall conditions

  • Caroline Costa Lucas
  • Italo Cesar Lima
  • Tatiane Martins Garcia
  • Tallita Cruz Lopes Tavares
  • Pedro Bastos Macedo Carneiro
  • Carlos Eduardo Peres Teixeira
  • Sonia Bejarano
  • Sergio Rossi
  • Marcelo O. Soares

Abstract

Coral reefs in turbid waters have been hypothesized to be a refuge from climate change. These naturally occurring communities were brought into the spotlight because some of their species exhibited record levels of resistance to marine heatwaves (MHWs) by disturbance-tolerant corals. However, long-term monitoring data on the drivers of coral bleaching in these extreme reef habitats are scarce. Here, we describe the population structure and bleaching rates of a widespread and resilient coral (Siderastrea stellata). We examine the links between environmental factors, namely, rainfall, wind speed, turbidity, solar irradiance, sea surface temperature, MHWs, and coral bleaching status under the worst recorded drought cycle in the Tropical South Atlantic (2013–2015). We examined 2880 colonies, most of which (∼93%) fit in the size group of 2–10 cm, with a small number (∼1%) of larger and older colonies (>20 cm). The results indicated the absence of MHWs and normal sea surface temperature variations (between 26.6 °C and 29.3 °C), however, we detected an extreme rainfall deficit (30–40% less annual volume precipitation). In general, a high proportion (44–84%) of bleached colonies was found throughout the months when turbidity decreased. Siderastrea is the only reef-building coral that comprises this seascape with encrusting and low-relief colonies. During drought periods, cloudiness is reduced, turbidity and wind speed are reduced, and solar irradiance increase, driving coral bleaching in turbid reefs. However, episodic rainfall and higher wind speeds increase turbidity and decrease coral bleaching. Our hypothesis is that turbidity decreases during drought periods which increases bleaching risk to corals even without thermal stress. Our results suggest that turbidity may have related to wind and rainfall to provoke the coral bleaching phenomenon.

Cite this activity

Lucas C.C., Lima I.C., Garcia T.M., Tavares T.C.L., Carneiro P.B.M., Teixeira C.E.P., Bejarano S., Rossi S. and Soares M.O. (2023) Turbidity buffers coral bleaching under extreme wind and rainfall conditions. 192: 106215. 10.1016/j.marenvres.2023.106215

Details

Research topics
Date 09.10.2023
Volume 192
Pages 106215
Open Access Closed Access
Open Access Status Closed Access
Eprints_link https://cris.leibniz-zmt.de/id/eprint/5294
Peer-Reviewed

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