Spatially Modeling the Synergistic Impacts of Global Warming and Sea-Level Rise on Coral Reefs in the South China Sea

Xiuling Zuo,Qi Wang,Huisheng Wu,Yinghui Wang,Fenzhen Su,Kefu Yu

doi:10.3390/rs13132626

Abstract

Global warming and sea-level rise (SLR) induced by rising atmospheric CO2 concentrations can cause coral bleaching, death, and submergence of the world’s coral reefs. Adopting the GIS and RS methods, we modeled how these two stressors combine to influence the future growth of the atolls and table reefs of three archipelagoes in the South China Sea (SCS), based on geomorphic and ecological zones. A large-scale survey of the coral communities in Xisha Islands in 2014, Dongsha Islands in 2014–2016 and Nansha Islands in 2007 provided zone-specific process datasets on the range of reef accretion rates. Sea surface temperature and extreme (minimum and maximum) SLR data above 1985–2005 levels by 2100 in the SCS were derived from the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) models forced with the Representative Concentration Pathways (RCPs). Our model projected that: (1) the Xisha Islands and Dongsha Islands may have a better growth status, because the reef flat biotic sparse zone may be recolonized with hard coral and become a biotic dense zone; (2) the southern Nansha Islands reefs have a risk of stopping growing due to their earlier annual bleaching years. The increasing of water depths of these reefs is stronger in the RCP with more emissions. Our approach offers insights into the best-case and worst-case impacts of two global environmental pressures on potential future reef growth under a changing climate.

Highlights

Since the industrial revolution began at the start of the 19th century, the burning of fossil fuels and the unprecedented increases in the amount of atmospheric carbon dioxide (CO2 ) and other greenhouse gas have caused a marked increase in the temperatures of the atmosphere and ocean, and widespread ice sheets to melt and sea-level to rise [1].Anthropogenic global warming has created a serious threat to coral reef ecosystems around the world with widespread coral bleaching events being related to the increase of sea surface temperatures (SSTs) [2,3,4]
The geomorphic and reef flat ecological zones were mapped with 94.4% overall accuracy using our mapping method (Table 1)
Errors of omission were highest for the biotic sparse zone of reef flat and the biotic dense zone of reef flat (Table 1)

Summary

Introduction

Anthropogenic global warming has created a serious threat to coral reef ecosystems around the world with widespread coral bleaching events being related to the increase of sea surface temperatures (SSTs) [2,3,4]. The future of global coral reef ecosystems under global warming has been predicted using coupled ocean–atmosphere general circulation models (GCMs) [2,8,9,10]. These projections show that widespread coral bleaching event will become more frequent

Objectives

Methods

Results