Spatiotemporal Variability of Hypoxia and Acidification Dynamics in a Subtropical Estuary
Citation:
Aukamp, J., B. Jarvis, Y. Wan, AND A. Boshinski. Spatiotemporal Variability of Hypoxia and Acidification Dynamics in a Subtropical Estuary. Ocean Sciences Meeting 2024, New Orleans, LA, February 18 - 23, 2024.
Impact/Purpose:
This abstract is for a presentation to be given at ASLO Ocean Sciences 2024. The research presented here will summarize field monitoring of hypoxia and acidification in Pensacola Bay.
Description:
Low dissolved oxygen (DO) and hypoxia (DO<2 mg l-1) in estuarine ecosystems presents unique challenges to marine species which are worsened by coincident low pH or acidification resulting from eutrophication. Few studies have documented spatiotemporal gradients of hypoxia and acidification across the estuarine salinity gradient and at timescales ranging from hours to months. We combined spatial surveys and high frequency time-series data of DO and carbonate parameters to characterize the frequency, duration, and spatial extent of low oxygen and pH conditions in Escambia Bay. Continuous monitoring revealed distinct spatial patterns of low DO and pH that varied over a period of hours to days, with sites exhibiting both prolonged and diel-cycling hypoxia/anoxia and low pH. Over longer timescales we further identified seasonal shifts in bottom water pH and DO saturation that coincide with seasonal changes between net autotrophy and heterotrophy. Close coupling of DO and pH in both continuous monitoring and spatial survey datasets suggests a strong metabolic effect on bottom water pH. These results highlight the highly variable nature of both hypoxia and acidification dynamics in subtropical estuaries and further underscore the need for targeted monitoring with sufficient spatial scales and temporal frequencies.