Impact of large storm events with different meteorological characteristics on estuarine ciliate biomass

Abstract

Microzooplankton are important consumers of phytoplankton production in estuaries and are links to higher trophic levels. We examined the impact of several large storms varying in their meteorological characteristics on the distribution of ciliates, a key component of the microzooplankton community in North Carolina's Neuse R. Estuary (NRE). Ciliate biomass was largely unaffected by Tropical Storm ("TS") Helene, except for dissipation of a patch of elevated ciliate biomass at a frontal zone in the upper estuary. Following passage of Hurricane ("H") Isabel, mean ciliate biomass increased 2-fold, with the most dramatic increases occurring in the upstream region that was influenced by freshwater runoff. H Alex had minimal impact on ciliate biomass, but shortly after its passage, Tropical Depression Bonnie and TS Charley passed over the region with significant rainfall. Ten days after passage of those storms, ciliate biomass increased throughout the NRE, with the most dramatic increases again seen in the upper freshwater-influenced region of the estuary. Overall, these findings suggest that the response of estuarine ciliates to storm events is complex, although some coherent patterns were detected in terms of the overall biomass response. Given that storms represent important drivers of ecological processes in estuaries and that the US East and Gulf Coasts are in a period of elevated storm activity, further work is warranted to fully understand the impact of storms on trophic transfer in estuaries. © The Author 2008. Published by Oxford University Press. All rights reserved.