生物多様性と絶滅危惧種のジャーナル

Reactions of Foraminiferal Assemblages on Tropical Coastal Beachrocks to Hydrodynamic and Sedimentary Processes

Abstract

Yanli Lei*

The interaction between sedimentary processes and hydrodynamics has a significant impact on coastal habitats. Given the sensitivity and specificity of living populations or the presence of dead specimens, the assemblages of benthic foraminifera are structured by environmental factors, making them excellent indicators of the main processes in coastal settings. The present study evaluated environmental variables in beachrocks of Brazilian tropical sandy beaches using benthic foraminifera as a proxy. In order to describe foraminiferal assemblages (27 samples), as well as to conduct grain size analysis and CaCO content determination, samples were collected at the base of coastal beachrocks on the beaches Pina, Enseada, and Toquinho (northeastern, Brazil) (27 samples). Medium to coarse sand of terrestrial origin, fairly sorted and roughly symmetrical, made up the majority of the deposits. Rip currents, littoral drift and the primary forces behind the size, sorting, and redistribution of the sediments are littoral drift, rip currents, and waves. A total of 6829 foraminifera from 42 genera and 76 species were found.