An ecological study of the benthic meiofauna and macroinfauna of a soft bottom area on the Texas outer continental shelf

Abstract

The distribution and abundance of meiofauna and macroinfauna from ten stations on the outer east Texas continental shelf were examined. The meiofauna ranged from 519 to 896 individuals per 10 cm² and 3.95 to 6.49 mg wet weight per 10 cm², while the macroinfauna varied from 340 to 1720 individuals per m² and 0.75 to 5.44 g wet weight per m². The permanent meiofauna exceeded the macroinfauna by an average of 990:1 numerically and 1.48:1.00 on the basis of wet weight. The density and standing crop of the macroinfauna were depauparate compared to other continental shelf localities outside the Gulf of Mexico. However, the species richness, based on rarefaction curves of the polychaete-bivalve taxocenes, was higher than that of other investigated areas. Cluster and factor analysis techniques were used to construct site and species groups for both foraminiferans and macroinfauna. The foraminiferans generally formed a single assemblage, while the macroinfauna was divisible into three site groups that closely corresponded to substrate differences. Pearson product-moment correlations and stepwise multiple linear regression were utilized in an effort to analyze the spatial variations of the fauna in relation to measured environmental parameters. The macroinfauna generally showed higher correlations to the measured environment, particularly to sediment grain sizes. Correlations between numerically dominant macroinfaunal species and the measured environmental parameters indicated that the distribution and abundance of each species were dependent on a particular suite of parameters. Numerically dominant species that showed high correlations to similar grain sizes often differed in feeding type.