Stochastic event alters gelatinous zooplankton community structure: Impacts of Hurricane Sandy in a Mid-Atlantic estuary

Climate change has increased hurricane activity and intensity, leading to greater destructive forces impacting coastal communities. Barnegat Bay, New Jersey, USA, is a shallow Mid-Atlantic estuary with considerable anthropogenic development which shows vulnerability to elevated storm surges and coastal flooding. Gelatinous zooplankton were sampled monthly in the summer prior to Hurricane Sandy in October 2012, with the community dominated by 2 species, Chrysaora quinquecirrha and Mnemiopsis leidyi. These 2 species showed inverse distributions, with C. quinquecirrha dominating in the northern, lower-salinity region and M. leidyi abundant in the southern, high-salinity region of the estuary, with significant top-down control of M. leidyi by C. quinquecirrha. Following Hurricane Sandy, substantial changes in the community occurred, with a 64% increase in gelatinous zooplankton species richness. C. quinquecirrha population density significantly declined by more than 50% in 2013 (from 0.033 to 0.013 m^-3) and remained lower in 2014 (0.012 m^-3). Concomitantly, M. leidyi populations significantly increased from 2.4 to 5.4 m^-3 in 2013 but dropped in 2014. The drop in 2014 was unexpected, as the C. quinquecirrha population remained low. However, the increasing density and diversity of other gelatinous species in 2013 and 2014, including Salpa sp., Turritopsis nutricula, Nemopsis bachei, Bougainvillea muscus, and Rathkea octopunctata, changed the community composition. Consequently, the destructive forces of Hurricane Sandy cascaded throughout the community by the elimination of polyp habitat for the dominant predator, thereby opening the system to community succession.