Spatial and temporal patterns of zooplankton community structure in the northern Gulf of Mexico (2015-2017)

Jillian Gilmartin, Texas A&M University at Galveston, Galveston, TX, United States and Hui Liu, Texas A&M University at Galveston, Marine Biology, Galveston, TX, United States
Biophysical patterns and processes exhibit both spatial and temporal variability, and therefore analyses of spatial autocorrelation can reveal insights into the forces structuring ecosystems. Zooplankton species which exhibit large variability between sites can serve as sensitive indicators of change in an ecosystem, whereas zooplankton communities which exhibit large temporal and spatial variations can be studied to understand factors influencing spatial dynamics for higher trophic levels. The present study examines the spatial variability among the mesozooplankton community of the northern Gulf of Mexico. Zooplankton samples were collected vertically using 202µm mesh in spring and summer of 2015, 2016, and 2017 in the northern Gulf of Mexico and enumerated to species or the nearest taxonomic level. We ran community level spatial autocorrelation tests by cruise, by year, and across regions to understand temporal changes in zooplankton communities. In general, when analyzing spatial autocorrelation in zooplankton abundance, between-year variability was greater than within year variability. Zooplankton distribution exhibited relatively greater variability in spatial autocorrelation between years in the same region, suggesting that oceanographic processes (i.e. Loop Current circulation and Mississippi River plume) are important in controlling zooplankton spatial distribution in the northern Gulf of Mexico.