Polychaete feeding behavior and geographical distribution in the Gulf of Mexico
Polychaete annelids contribute greatly to macrofaunal species diversity in dynamic deep-sea ecosystems. The aim of our study was to assess the functional composition of deep-sea polychaete assemblages in the Gulf of Mexico. We examined various factors influencing the diversity, density and distribution of this taxon. Polychaete assemblages are ubiquitous in the deep sea but abundance, diversity and species composition are sensitive to changing environmental conditions. We tested the hypothesis that polychaete feeding-guilds show a stronger correlation with depth and environmental characteristics than their taxonomic groupings. Polychaetes were sampled from a total of 51 stations consisting of 7 transects and individual juxtaposed stations in the Gulf of Mexico. Additionally, we also carried out ecological niche modeling (ENM) using the Maximum Entropy model (MaxEnt) estimate the potential geographical distribution of the most dominant polychaete species found in our study.
The highest species diversity was present at the central and the upper slope of the Mississippi trough area. Polychaete density decreased exponentially from the shallow, central regions to the eastern and western regions. Diversity in polychaete feeding-guilds was high on the Mississippi trough, upper and mid-slope regions and declined to a few guilds on the abyssal plain region. A significant correlation was observed between polychaete feeding-guilds and environmental variables. Using species presence-only data for ENM we generated potential distribution maps of the four most dominant polychaete species found at a regional scale in the Gulf of Mexico. We conclude that that feeding-guild analysis and ecological niche modeling are powerful tools for polychaete diversity studies, as they provide a clear understanding of the spatio-temporal patterns and trophic organization of deep-sea benthic assemblages.