Response of Soft-Bottom Benthos to Annual Catastrophic Disturbance in a South Florida Estuary

Abstract

ABSTRACT: A portion of Hillsborough Bay (Tampa, Florida, USA), part of the Tampa Bay estuary, undergoes annual summer defaunation, presumably due to hypoxia. Dissolved oxygen levels are very low (< 1.0 mg 1-l) at the times of the defaunations. In the ensuing period between defaunations, recolonization occurs. Monthly samples for 42 consecutive months were collected by SCUBA-diver-operated, hand-held PVC cores and screened through a 0.5 mm sieve. Eight species, Mysella planulata, Arnpelisca abdita, Streblospio benedicti, Grandjdierella bonnieroides, Mulinia lateralis, Mediomastus californiensis, Cyclaspls sp. and Nereissuccinea were numerically dominant, accounting for more than 95 % of the total density during the entire penod. These 8 species are all classified as r-strategists and utilize several dispersal mechanisms to attain large populations rapidly. Circumstantial evidence is present