%0 Journal Article
%T Assessment of Longitudinal Gradients in Nematode Communities in the Deep Northern Gulf of Mexico and Concordance with Benthic Taxa
%A Jyotsna Sharma
%A Jeffrey G. Baguley
%A Paul A. Montagna
%A Gilbert T. Rowe
%J International Journal of Oceanography
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/903018
%X Meiobenthic nematode assemblages were examined at 16 stations along two transects on the eastern and western boundaries of the deep northern Gulf of Mexico (dNGOM) at depths of 212¨C3000£¿m. The highest abundance (297 individuals 10£¿cm£¿2) and number of genera (71) occurred at stations near the Mississippi River delta. Number of genera decreased with increasing depth, and showed differences in community composition between the east and west regions. The dominant family, Comesomatidae, was represented by Sabatieria that was present at most shallow stations but absent at greater water depths. A significant difference in nematode feeding morphology was observed between depth groups but not between the two transects at different longitudes. Patterns of nematode community structure are congruent with harpacticoid copepods. Overall, the higher abundance and diversity of nematodes in the north-central Gulf of Mexico is consistent with findings of other benthic taxa and reflects organic material loading from the Mississippi River driving deep sea communities in the Gulf. The east-west gradient in composition of nematode communities suggests that nematode assemblages have well-defined distribution patterns similar to other meiobenthic taxa in the GOM but they are not aligned in the bathymetric zones observed in macrofauna, megafauna and demersal fishes. 1. Introduction Deep-sea biodiversity remains woefully understudied, and it is estimated that only 1% of marine species is currently described [3]. Most studies of deep-sea benthic diversity are based on mega- or macrofaunal organisms, but studies of the meiobenthos and nannobenthos have revealed a diverse fauna [4¨C6]. Meiobenthic abundance and diversity exceed that of macrofauna and megafauna, and the biomass of the meiofauna community dominates that of macro- and megafauna with increasing water depth [7]. Comparison of biomass and respiration rates also suggests that meiofauna have greater rates of carbon flow through food webs in deeper waters in the Gulf of Mexico than the larger macrofauna and megafauna [8, 9]. As the numerically dominant meiofaunal taxon in deep-sea sediments, nematodes play significant roles in marine biogeochemical cycles through bioturbation and related processes that enhance sediment oxygenation and solute transport, thereby increasing rates of demineralization [10¨C12]. However, despite their numerical dominance, high diversity, and functional significance [13, 14], studies of this ubiquitous phylum are rare. Studies of nematode biodiversity in the deep sea conducted in the Pacific and
%U http://www.hindawi.com/journals/ijocean/2012/903018/