"Estimating the Carbon Flux of Argyropelecus aculeatus Within the Gulf " by Sidney R. Trimble

Defense Date

12-6-2024

Document Type

Thesis

Degree Type

Master of Science

Degree Name

Marine Science

First Advisor

Rosanna J. Milligan, Ph.D

Second Advisor

Tracey T. Sutton, Ph. D

Third Advisor

D. Abigail Renegar, Ph. D

Keywords

Hatchetfishes; Biological Carbon Pump; Carbon Flux Model; Diel Vertical Migration; Gulf of Mexico

Abstract

Anthropogenic impacts have led to increased levels of anthropogenic carbon within the atmosphere and the world’s oceans. The Biological Carbon Pump (BCP) plays a key role in reducing the amount of carbon in the atmosphere and oceans by aiding in the export and sequestration of anthropogenic carbon. This occurs when carbon exchange between the atmosphere and the upper ocean takes place, and the carbon is then transferred down into the deep sea. Mesopelagic fishes may aid in this process of carbon transfer. Though the role of mesopelagic fishes is understudied in our world’s oceans, there are previous studies that focus primarily on myctophids (lanternfishes). To gain a better understanding of the extent that mesopelagic fishes transport carbon down the water column into the deep sea we can create a carbon flux model. Though not previously analyzed, hatchetfishes are one of the most abundant fishes in the world and some species perform diel vertical migration, leading to them having a role in in the export and sequestration of anthropogenic carbon. This study will focus on the species Argyropelecus aculeatus and create individual-based carbon flux models to analyze the daily activities of A. aculeatus and estimate the carbon flux of these fishes examining their potential contributions as migrators and non-migrators to the BCP within the Northern Gulf of Mexico. The results show that Carbon flux estimates for a migrating A. aculeatus with a migration range of 200 – 600 m has a mean daily carbon flux of 5.64 x 10-1 mg C d-1 (3.11 x 10-1 - 9.80 x 10-1 mg C d-1). Migrating A. aculeatus with a migration range of 200 – 1,000 m have a mean daily carbon flux of 6.41 x 10-1 mg C d-1 (3.32 x 10-1 – 11.7 x 10-1 mg C d-1). Non-migrating A. aculeatus have a mean daily carbon flux estimate of 2.18 x 10-1 mg C d-1 (1.02 x 10-1 – 3.41 x 10-1 mg C d-1). The mortality carbon flux pathway and the respiration and growth carbon flux pathway are the greatest contributors to a total 24-hr carbon flux estimations for both migrating A. aculeatus and non-migrating A. aculeatus. Estimated results from this study provide a better understanding of how an A. aculeatus contribute to carbon flux within the Gulf of Mexico and their role within the oceanic BCP.

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