Kinorhynch communities on the Louisiana continental shelf

Abstract

Kinorhynchs are microscopic invertebrates that are part of the meiofaunal community. Their diversity and distribution has been relatively unstudied in the Gulf of Mexico until the past few years. Past studies from Troy University have reported 32 species of kinorhynchs in the Gulf, from Texas to Florida. This study reports a re-sampling effort which focused on the Louisiana shelf, in an attempt to further understand the relationships between the shelf sediment and the kinorhynch diversity. For this work, sediment was sampled at 16 locations in 2015 using a multicorer. Kinorhynchs were isolated using centrifugation. Animal densities ranged from <1–33/10 cm2, with an average of 12 animals/10 cm2. A total of 345 animals were identified to the species level. Echinoderes bookhouti was the most abundant animal, which along with E. augustae, E. spinifurca, E. skipperae, and Leiocanthus cf. L. langi accounted for almost all the identifications. Additionally, we report four new species records for the Gulf of Mexico: Pycnophyes alexandroi, P. norenburgi,Antygomonas paulae, and Leiocanthus cf. L. corrugatus. These data reveal a multi-year trend with regard to dominant kinorhynch species within the Gulf of Mexico, and support an earlier study of Gulf kinorhynchs from 2013–2014. Multivariate analysis revealed that sediment locations with higher densities of kinorhynchs associated with higher levels of organic matter, and sediment locations with low densities associated with sandy sediment.