7. Linking Abiotic Variables with Macrofaunal and Meiofaunal Abundance and Community Structure Patterns on the Gulf of Mexico Continental Slope

The Deep Gulf of Mexico Benthos (DGoMB) program was designed to determine patterns of abundance and diversity of meiofauna and macrofauna in the northern Gulf of Mexico continental slope between 300 m and 3700 m depth. Abundance of all taxa was significantly influenced by the particulate organic carbon (POC) flux. The abundance of meiofauna, macrofauna, crustaceans, and mollusks increased with increasing clay content, but clay had no significant effect on harpacticoid or polychaete abundance. Polychaete diversity was significantly correlated to POC flux, but mollusk diversity was correlated to sediment properties. Polychaetes had the highest average abundance and species richness. Harpacticoids were the least abundant of the four taxa, but had the highest values of Hill’s diversity index and Pielou’s evenness index. Harpacticoids and Crustaceans had high species turnover rates, resulting in low similarities of the respective faunas between sampling stations, whereas mollusks and polychaetes were more similar between different sampling stations. Overall, there were interannual differences in abundance patterns of meiofauna and macrofauna, similar community structure patterns among the taxa, and unique distributions of diversity with respect to depth and longitude.