The classification and structure of marine macrobenthic assemblages at Arthur Harbor, Anvers Island, Antarctica
In January-February 1971 five replicate 0.07 m² Van Veen grabs were obtained from each of 12 stations in Arthur Harbor and nine Van Veen grabs were obtained from two stations in nearby Bismark Strait. The 69 grab samples yielded 78,395 individuals which were separated into 282 taxa, including 108 sp...
| Main Author: | |
|---|---|
| Other Authors: | , , , , , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English unknown |
| Published: |
Oregon State University
|
| Subjects: | |
| Online Access: | https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/5712m8675 |
| Summary: | In January-February 1971 five replicate 0.07 m² Van Veen grabs were obtained from each of 12 stations in Arthur Harbor and nine Van Veen grabs were obtained from two stations in nearby Bismark Strait. The 69 grab samples yielded 78,395 individuals which were separated into 282 taxa, including 108 species of annelids (54.5% of the individuals), 117 species of arthropods (30.3%), 35 species of molluscs (11.3%) and 22 species in other phyla (4.0%). The density of macrofauna (17,522 individuals/m²) found in Arthur Harbor was high compared to other reported areas. This high density was considered to be the result of high organic input from phytoplankton, phytobenthos and attached macroalgae, the efficient utilization of organic matter by macrobenthos and the slow growth rate of macrobenthic species as an indirect result of cold temperatures. Diversity values were moderately high with high species richness values and low evenness values. The high species richness values may be the consequence of seasonal constancy of temperature and salinity in Arthur Harbor, while low evenness values probably result from the physical stress of iceberg grounding coupled with high organic input. Six macrobenthic assemblages (site groups) and 11 species groups were found in the study area by classification analysis (Bray-Curtis dissimilarity, group-average sorting). Station groups were described by dominant species, density and diversity. Species groups were described by the dominance, fidelity, constancy, and percent abundance of constituent species restricted to site groups. The existence of discrete assemblages derived from the classification analysis was supported by direct ordination. Assemblages were interpreted to be areas of relative homogeneity which interrupt a general continuum of distribution of species with depth. The depth gradient probably represents several factors including increased constancy of temperature and salinity, lower organic input from attached macroalgae and phytobenthos, and a reduced incidence of iceberg ... |
|---|