Assessing Cold-Snap and Mortality Events in South Florida Coastal Ecosystems: Development of a Biological Cold Stress Index Using Satellite SST and Weather Pattern Forcing

Abstract

Water temperature is considered both a controlling and lethal factor in coastal ecosystems, influencing behavioral and physiological responses in marine organisms. Abrupt weather events such as severe cold front passages and accompanied changes in weather conditions have led to sharp decreases in water temperatures, metabolic stress, and incidences of mortality in marine organisms. In this paper, we assess the weather-related factors associated with physical and biological response in South Florida systems through historical sea surface temperature (SST) from satellites and the use of a synoptic climatology spanning over 30 years. We utilize previous categorizations of sea-level pressure and newly developed categorizations of 850-mb temperature reanalysis data to define circulation and temperature patterns across the southeastern US and adjacent Gulf of Mexico. Systematic connections are seen between particular circulation and temperature patterns characteristic of enhanced north-to-south circulation and cold air outbreaks, SST, and turtle strandings data over the Florida Panhandle region for the period 2006–2013. Identified weather forcing variables associated with sharp SST decreases and turtle stuns are presented and assist in the formulation of a moving cold-stress index for South Florida coastal ecosystems. Results demonstrate the potential of using synoptic climatological analysis and derived indices for tracking and modeling changes in SST and other indicators related to biological health.