Graduation Year

2024

Document Type

Thesis

Degree

M.S.

Degree Name

Master of Science (M.S.)

Degree Granting Department

Marine Science

Major Professor

Kendra Daly, Ph.D.

Committee Member

Pamela Hallock Muller, Ph.D.

Committee Member

Mark Luther, Ph.D.

Keywords

Copepods, Loop Current, Warm-core eddy, West Florida Shelf, Yucatan, Zooscan

Abstract

My research focused on characterizing the zooplankton community of two regions in the Gulf of Mexico (GOM) along two transects, one across the middle of the GOM from Tuxpan, Mexico, to St. Petersburg, FL, and one along the northwestern coast of Cuba. Zooplankton bongo samples and associated environmental and physical processes were examined. These data were collected during two Center for Integrated Modeling and Analysis of Gulf Ecosystems (C-IMAGE) expeditions aboard the R/V Weatherbird II, during September 2015 (GOM) and May 2017 (Cuba). A Zooscan imaging system was used to identify and enumerate zooplankton taxa. Then zooplankton abundance, composition, and diversity were compared to environmental and physical processes occurring at the time of sampling. Zooplankton abundance and composition showed variability across both regions, with copepods being the dominant taxa. Ostracods and decapods also were abundant at specific stations in the GOM, while foraminifera dominated the western-most region along the coast of Cuba. These dominant taxa are consistent with previous studies. Zooplankton species diversity was similar in both regions with ranges in the GOM of 0.9-1.9 and in Cuba ranges of 0.8-2.2. The highest diversity indices were at off-shelf stations, which is consistent with previous studies. Environmental factors in these regions, such as the Loop Current System, associated eddies, and runoff from surrounding land areas, influenced the hydrographic conditions within the surface layers of these regions, as well as the zooplankton. Zooplankton abundances were highest on the West Florida Shelf, some of the central GOM stations associated with cyclonic eddies near the Yucatan shelf, and the Mexican shelf slope. Along the northwestern coastal region of Cuba, the stations located on the western side had the highest zooplankton abundances, with one station dominating the entire transect. These results reveal that the abundance and community structure of zooplankton in these regions varied depending on the influence of water column properties and their impact on food availability (chlorophyll) for zooplankton.

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