Acute Tissue Death (white syndrome) Affects the Microenvironment of Tabular Acropora Corals

Abstract

White syndrome (WS) is a collective term for coral diseases that cause acute tissue loss, resulting in apparently healthy tissue bordering on exposed skeleton. In this study, the microenviron-mental condition and tissue structure of WS-affected tabular acroporid corals were assessed by O2microelectrodes and histological techniques. The high spatial resolution of the microelectrode measurements enabled an evaluation of the extent of physiological changes at, and 2 cm away from, the WS border. Respiration of the coral host was decreased on the skeleton–tissue border but was comparable to that of healthy corals only 2 cm away from the border. Histological data, however, showed a decrease in mesogloea thickness on and 2 cm away from the WS border, which correlates with a previously observed allocation of photoassimilates away from the WS border. We suggest that there are colony-wide negative effects of WS which affect only the host physiology and, as disparate etiologies are evident in WS, these must be distinguished through the utilization of a multiple tool approach.