Experiments on predation, substrate preference, and colonization of benthic foraminifera at the shelfbreak off the Ft. Pierce Inlet, Florida

Abstract

Oceanographic Institution and located off the Ft. Pierce Inlet, Florida, at a depth of 125 m. The experiment allowed us to examine: 1) the effects of open vs screened speed of colonization^ Two sets Of sediment-fi11ed boxes were ’laced at a June 1980. Each set contained an uncovered box of mud, an uncovered box of sand, a screened box of mud and a screened box of sand. One set was retrieved on 14 July 1980, the other on 1 October 1980. Sediments from the natural environment were also sampled at these recovery times. Densities of 14 species of benthic foraminifera were analyzed by two-way ANOVA’s. For most species, densities were highest in screened boxes, indicating that predation significantly reduces foraminiferal densities in the uncovered boxes. After six weeks the uncovered box of mud had densities comparable to the natural environment. The uncovered sand-filled boxes had very low densities (poor colonization), causing us to suggest that some mud is necessary to maintain foraminiferal populations. Analysis of the screened boxes retrieved on 1 October 1980 indicates that there was no significant difference between mud and sand substrates for any of the species. This suggests that once colonization had taken place, particle size was not an important influence. mud-filled box. depth Of 125 m Off the Ft. Pierce Inlet, F1orida, On 3 boxes; 2) the effect o fa sand vs mud substrate; 3) the