Relationship of Morphologic Variation and Environment in Recent Bolivina (Foraminiferida) from Northwestern Gulf of Mexico: ABSTRACT

Abstract

This study investigates intraspecific morphological variation trends of recent benthic foraminifera in relation to depth and environmental factors (temperature and salinity). Twelve samples were obtained from traverses trending south-southeast from offshore Galveston, Texas, to the Sigsbee Deep. Samples are cuts of short cores (30-40 cm, 12-16 in.) from 33-3,431 m (108-11,257 ft) in depth. Fifty specimens from the total population (all growth stages) and 30 specimens of a specific growth stage were randomly selected for each of 4 foraminifera species, Bolivina albatrossi, B. lowmani, B. subspinescens, and B. ordinaria, from each sample site. Test outline, as an indicator of overall shape, was quantified by an automated video digitizer using closed-form Fourier series anal ses. Significant variations in shape outline components were tested for their relationships to bathymetry and environmental factors using analysis of variance and multiple discriminant analysis for both total populations and the specific growth stage. Morphologic trends relatable to both depth and environmental variables are recognizable in the 2 data sets. Such trends may be observable in the fossil record, thus indicating relative depths and suggesting possible absolute depth and values of environmental variables. This morphologic approach may be utilized even though different species are incorporated in analyses and different absolute depths involved. End_of_Article - Last_Page 479------------