Meiofauna community structure and function in the northern Gulf of Mexico deep sea

by 1977- Baguley, Jeffrey Greer

Meiofauna are ubiquitous in deep-sea soft sediments and exhibit high abundance compared to larger-sized invertebrates (e.g., macrofauna). The northern Gulf of Mexico (NGOM) deep sea is characterized by topographical contrasts, with the flat topography of the Florida slope followed by the precipitous depth increase of the Florida escarpment; the complex Texas/Louisiana slope with numerous basins and knolls; and numerous canyon features such as the Mississippi Trough and DeSoto Canyon. In order to more fully understand the distribution of meiofauna and how they respond to topographic, geochemical and physical forcing in the northern Gulf of Mexico, meiofauna abundance and environmental variables were analyzed in a hypothesis-based univariate and multivariate design. Meiofauna abundance is significantly related to water depth, but also exhibits significant longitudinal differences resulting from proximity to Mississippi River outflow. Canyon features in proximity of Mississippi River outflow were found to greatly enhance meiofauna abundance. The Florida Escarpment interacts with Mississippi River inflow and the Loop Current to enhance meiofauna abundance at stations lying directly above and below the escarpment. Multivariate comparisons of meiofauna abundance with environmental variables reveals a strong Mississippi River influence. River outflow alters local sediment characteristics, and interacts with loop 1 current eddies and dynamic slope topography to increase POM flux in the northeastern region, thus creating areas of higher than normal meiofauna abundance.