Abstract
In the northern Gulf of Mexico, shelf hypoxia poses serious risks to fisheries, coastal economies, and ecosystem health. Although a primary driver of dissolved oxygen dynamics is nutrient loading, physical forcing (wind conditions, stratification, etc.) and their interannual variability also have a role in the coastal shelf regions. This project aims to assess hypoxia and related physical stressors on the Alabama shelf, where little monitoring has occurred despite growing evidence of substantial hypoxic conditions. The connections between extreme events (tropical storms, marine heatwaves), physical stressors (temperature, stratification, wind), and hypoxia occurrence were investigated using monitoring surveys across coastal Alabama over three summer seasons (2023-2025). These surveys were conducted to better understand the spatial patterns of dissolved oxygen on the shelf. The results of this study are expected to facilitate the development of more effective mitigation and adaptation strategies to address the impacts of physical processes on hypoxia in coastal oceans.
Purpose
Casting CTD data were collected at multiple stations to better understand the three-dimensional structure of dissolved oxygen on the shelf. This survey consisted of a survey grid of two along-shelf lines along the 12 m and 20 m isobaths as well as an across-shelf transect going from the Main Pass, Mobile Bay, out to the 35 m isobath. Sampling on the surveys consisted of CTD profiling data from a Sea Bird Electronics 25 plus casting CTD with depth, salinity, temperature, dissolved oxygen concentration, dissolved oxygen percent saturation, pH, density, and chlorophyll fluorescence. The data were collected every ~5 cm for each vertical cast.
DOI: 10.57778/zmph-zw51
Suggested Citation
Dzwonkowski, B., Puzhankara, A., Lehrter, J., Mohan Rao, D. R., & Lockridge, G. (2026). Summer shelf dissolved oxygen surveys in coastal Alabama from 2023-06-01 to 2025-08-31 [Dataset]. dauphin. https://doi.org/10.57778/ZMPH-ZW51
Related Publication Citation
Attribution
This project was paid for [in part] with federal funding for the Alabama Center of Excellence from the Department of the Treasury under the Resources and Ecosystems Sustainability, Tourist Opportunities, and Revived Economies of the Gulf Coast States Act of 2012 (RESTORE Act) in cooperation with the State of Alabama Department of Conservation and Natural Resources under the Alabama Center of Excellence Program at the MESC/Dauphin Island Sea Lab.
