BENTHIC STUDIES IN BUZZARDS BAY II. THE MEIOFAUNA1

Abstract

During the summer of 1957 a study of the small metazoans (meiofauna), based on a series of Phleger core samples, was undertaken at three stations in Buzzards Bay, Massachusetts. The number of animals ranged from 1.69 x 105 to 1.86 x 106/m2, the dry weights varied from approximately 100 to 600 mg/m2. The nematodes and kinorhynchs, which comprised between 89 and 99% of the total mieofauna, were studied in detail. The sandy localities (stations P and J) were characterized by a number of nematodes restricted to this habitat, particularly by three representatives of the genus Odontophora and by all representatives of the genus Leptonemella. The locality rich in fine deposits (station R) was characterized by the relative abundance of several nematodes, particularly of Terschellingia longicaudata, and the three kinorhynch species. It was possible to recognize an Odontophora‐Leptonemella community in the sandy habitats, and a Terschellingia longicaudata‐Trachydemus mainensis (kinorhynch) community in the silty habitat, the former being equivalent to the Ampelisca community, the latter to the Nucula proxima‐Nephthys incisa community described for the macrofauna in the same area. However, these “communities” can also be considered as two ecological groups of species, the former dependent on the presence of sand, the latter on that of fine deposits, which actually live side by side, forming an intricate meshwork of faunal combinations. Each combination is determined by the relative amounts of sand and fine deposits present.The uniformity of the nematode fauna within each station was greater than that between two different stations. Most important in determining the degree of faunal uniformity between paired samples is the similarity in their silt‐clay content. However, other mechanical factors also play a role.An analysis of the total species composition of the nematode fauna revealed that Terschellingia longicaudata was the most abundant species at station R, whereas at the stations P and J there were three or four equally dominant species. This is interpreted as indicating a splitting up of the sandy habitat into subhabitats. The simultaneous occurrence of closely related species in this environment further supports the conjecture.The distribution of “buccal types” amongst nematodes is correlated with the distribution of sediments.