Characterization of coral bleaching environments and their variation along the Bahia state coast, Brazil

Abstract

The relation between climate variability and coral bleaching in the Bahia reefs was investigated in an attempt to characterize the bleaching environments. The following 13-year time series were derived from the remote-sensing, analysis and reanalysis data: maximum summertime sea surface temperature (SST), maximum sea surface temperature (MaxSST) accumulated in 5 days (SSTAc5day), diffuse attenuation coefficient for downward irradiance at 490 nm (K ), rainfall and magnitude of surface wind fields, including the zonal (U) and meridional components. Principal component analysis, non-metric multidimensional scaling (MDS) and cluster and similarity analyses indicate the complex nature of the bleaching patterns and the influence of the strong 19971998 El Niño. A significant (global R-value = 0.65; p < 0.01) compounding effect of the reef location and bleaching intensity on the differentiation of bleaching environments was detected. A combination of high SSTAc5day and low K490 may cause coral bleaching in the northernmost reefs. Evidence clearly points to a scenario where the influence of reef location, bleaching year and intensity may produce a compounded effect that determines the bleaching environments in Bahia.