Long-term spatiotemporal variability of southwest Florida whiting events from MODIS observations

Abstract

Whiting events, or waters with high concentrations of fine-grained calcium carbonate, have been previously reported in southwest Florida using three years of observations from the Moderate Resolution Imaging Spectroradiometer. Here, the initial case study has been expanded to 13 years (2003-2015) with a statistical analysis that includes environmental data to document and understand longer term temporal and spatial variability of whiting occurrence in the same region. Annual mean whiting coverage (km2) peaked in 2011 and 2012, with the highest daily coverage in 2008 (126.0 km2). Over the time series, whiting events showed spatial variability based on distance from shore. Whiting seasonality also varied within the extended time series. Multivariate linear and non-linear regressions between mean whiting coverage (km2) and several environmental variables (wind speed, sea surface temperature, precipitation, and nearby river discharge) were performed over the entire study region as well as subregions based on spatial division from the coast line. Statistically significant correlations have been found with sea surface temperature and river discharge in subregions. These findings suggest that although observing spatial and temporal patterns of whiting events is possible with modern satellites, understanding the mechanisms regulating their initiation and maintenance is more difficult.