Defense Date

12-2-2022

Document Type

Thesis

Degree Type

Master of Science

Degree Name

Marine Science

First Advisor

Dr. Tamara Frank

Second Advisor

Dr. Rosanna Milligan

Third Advisor

Dr. Tracey Sutton

Keywords

MAR-ECO, Mid-Atlantic, Charlie Gibbs Fracture zone, Transform Faults, Sub-Polar Front, Decapoda Crustaceans, Deep Sea

Abstract

The Charlie Gibbs Fracture Zone (CGFZ) consists of two nearly parallel fracture transform faults that intersect the Mid-Atlantic Ridge (MAR) axis. This area has high primary productivity and biomass levels due to the topography and water. A predominant hydrographic feature of the MAR is the Sub-Polar Front (SPF) which runs along the southern edge of the CGFZ and is known as a biogeographical boundary for multiple species. As part of The Census of Marine Life project Patterns and Processes of the Ecosystem of the northern Mid-Atlantic (MAR-ECO), this study analyzed the abundance and distribution patterns of the CGFZ crustacean community (primarily Decapoda) surveyed during the 2009 Henry B. Bigelow voyage. This study determined that geographic location, in relation to the CGFZ, contributes to pelagic crustacean distribution, but the surrounding water masses are the primary drivers of abundance and diversity variations. Pelagic crustaceans had a larger abundance in the cold waters to the northwest of the CGFZ, presumably due to increased nutrients and food supply and higher diversity in the warmer southeastern waters, possibly due to dominating mesoscale eddies. Benthic crustaceans, however, had a higher abundance and increased diversity in the northwest, possibly due to the MAR acting as a biogeographic barrier separating the two geographic regions and reducing connectivity. Additionally, this study did not find the SPF to be an asymmetric species-specific biogeographic barrier for decapod crustaceans along the CGFZ.

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