Carlon Mark Eakin

Climate variability and change: monitoring data and evidence for increased coral bleaching stress

Coral reefs live within a fairly narrow envelope of environmental conditions constrained by water temperatures, light, salinity, nutrients, bathymetry and the aragonite saturation state of seawater. While the natural environment can be highly variable and potentially stressful to corals, humans are now placing the world’s coral reefs in crisis as a result of direct local- to regional-scale insults combined with accelerating global changes. The global-scale insults result from increased concentrations of atmospheric greenhouse gases that are rapidly acidifying and warming ocean waters. This chapter focuses on the changing physical environment surrounding coral reef ecosystems and especially the rising SSTs that are responsible for most mass coral bleaching events. We make use of improved long-term records of surface ocean climate to document SST changes in the vicinity of coral reefs and how the risk of SST conditions conducive to coral bleaching varies with climate variability such as El Nino--Southern Oscillation events. We describe the application of satellite-based SSTs and related products that have been developed to detect and monitor environmental conditions leading to coral bleaching around the globe.

Improvements to and continuity of operational global thermal stress monitoring for coral bleaching

Mass coral bleaching results from periods of elevated sea temperature. Satellite monitoring of thermal stress has enhanced the capacity for the management of coral bleaching events worldwide. Satellite-based monitoring tools provide reef managers with cost-effective observations of temperature conditions to monitor the risk of bleaching and to target in situ observations in areas under stress. This paper describes improvements to satellite remote sensing products from NOAA’s Coral Reef Watch to enhance product coverage and to correct identified errors in the production of coral reef-specific metrics for thermal stress. In addition, threats to the operational production of the thermal stress metrics are considered and a contingency plan is described to ensure continuity of operations.