Small-Scale Spatial Analysis of In Situ Sea Temperature throughout a Single Coral Patch Reef

Journal of Marine Biology, Volume 2011

Kelvin D. Gorospe and Stephen A. Karl

“Thermal stress can cause geographically widespread bleaching events, during which corals become decoupled from their symbiotic algae.  Bleaching, however, also can occur on smaller, spatially patchy scales, with corals on the same reef exhibiting varying bleaching responses.  Thus, to investigate fine spatial scale sea temperature variation, temperature loggers were deployed on a 4 m grid on a patch reef in Kāne’ohe Bay, Oahu, Hawai‘i to monitor in situ, benthic temperature every 50 minutes at 85 locations for two years.  Temperature variation on the reef was characterized using several summary indices related to coral thermal stress.  Results show that stable, biologically significant temperature variation indeed exists at small scales and that depth, relative water flow, and substrate cover and type were not significant drivers of this variation.  Instead, finer spatial and temporal scale advection processes at the benthic boundary layer are likely responsible.  The implications for coral ecology and conservation are discussed.”