Top-Down Effects of an Exotic Serpulid Polychaete on Natural Plankton Assemblage of Estuarine and Brackish Systems in the SW Atlantic

Abstract

ABSTRACT Pan, J. and Marcoval, M.A., 2014. Top-down effects of an exotic serpulid polychaete on natural plankton assemblage of estuarine and brackish systems in the SW Atlantic. The invasive reef-building polychaete Ficopomatus enigmaticus (Fauvel, 1923) has become well-established in many temperate brackish waters. To analyze preferences for different planktonic food sources, short-term (∼1.5 h), grazing microcosm experiments were performed in situ (n = 3), at two water bodies, a coastal lagoon (Mar Chiquita, MC) and the mixohaline stretches of a coastal creek (La Tigra, LT), Argentina, in January 2007. Relative clearance rates of phytoplankton were assessed for chlorophyll a size-fractions and for different groups of nanoplanktonic and microplanktonic protists. The two locations showed significant differences in plankton community structure. Nanoeukaryotes were the dominant group at both locations; the second most-abundant groups were diatoms at MC and ciliates at LT. There were significant differences ...