Correlation of Karenia brevis presence in the eastern Gulf of Mexico with rainfall and riverine flow.

Abstract

Counts of Karenia brevis from the eastern Gulf of Mexico between 1953 and 1998, binned by months and converted to presence/absence and duration, were analyzed for cross-correlation with rainfall and riverine flow. The region was divided into three sub-areas for analysis to accommodate geographic variation in potential forcing factors. The duration of the presence of K. brevis in northern Florida waters was not significantly related to either rainfall or flows. The central Florida region recorded significant correlations of K. brevis durations with a number of central Florida rainfall stations and with flows of most central and southern rivers examined. Lags were short (less than two months), if any, indicating relatively direct linkages. Relationships of K. brevis in southern Florida waters to rainfall, while similar to the central region, were significantly correlated for only a few south Florida rainfall stations and primarily with flows from the Peace River in south central Florida. Cross-correlations of K. brevis duration with departures of flow or rainfall from seasonal means were generally not significant.