Multi-storm analysis reveals distinct zooplankton communities following freshening of the Gulf of Mexico shelf by Hurricane Harvey

Abstract

AbstractTropical cyclones can highly modify coastal ecosystems through interactions between their unique set of meteorological traits and an ecosystem’s antecedent conditions. As such, resultant changes to biological community structure are likely storm-specific, yet our understanding of cyclone effects on marine communities is limited compared to communities in terrestrial and freshwater habitats. Using northwestern Gulf of Mexico (NWGOM) mesozooplankton data, we tested: (1) for differences between storm and non-storm community structure and dispersion; (2) if post-storm communities varied between one another; (3) if salinity drove differences; and (4) if physical drivers of abundance and evenness varied between storm and non-storm communities. Mesozooplankton community structure following Hurricanes Harvey, Ike, Rita, and during five non-storm years were analyzed. Post-Ike, post-Rita, and non-storm communities were similar while post-Harvey communities were distinct from non-storm years. A structural equation model revealed stratification and abundance drove community evenness. Post-Harvey mesozooplankton were more abundant in low salinity waters; a pattern muted during non-storm years. NWGOM mesozooplankton community structure was generally resilient to hurricane effects, except when large changes in salinity occurred. Our findings suggest resource availability for planktivorous predators and energy transfer within coastal food webs is altered following cyclones with high precipitation rates.