Seasonal Differences in Live Foraminiferal Densities: Case Studies from Tropical and Temperate Intertidal Environments

Abstract

Statistically significant differences (when p < 0.05 using the permutation t-test) among Live Foraminiferal Densities (LFDs) recovered in August, November, March and May were detected at tropical Caroni swamp, Claxton bay (Trinidad), temperate Cowpen marsh and Brancaster marsh (U.K.). The monthly mean LFDs of the foraminiferal metacommunities (all stations), assemblages (groups of stations defined by cluster analysis), and the agglutinated and calcareous specimens within each were compared separately. The LFDs of the Caroni swamp metacommunity did not fluctuate significantly among months, but significantly higher abundances of agglutinated specimens occurred in the upper assemblage in March; and calcareous specimens in the lower assemblage in November. At Claxton bay, monthly LFDs of the metacommunities and assemblages did not vary significantly, but calcareous and agglutinated species within each favoured dry (March and May) and wet (August and November) months respectively. At the temperate marshes, significantly higher LFDs of the metacommunities and assemblages were recorded in warmer months. August blooms of the Cowpen marsh metacommunity was attributed to agglutinated specimens in the upper assemblage, and calcareous specimens in the lower assemblage. May blooms of the Brancaster marsh upper assemblage were attributed to calcareous specimens, but there were no seasonal blooms of the lower assemblage.