Simulating Hypoxia and Acidification Dynamics in Pensacola Bay: Challenges Presented by Highly Dynamic Estuarine Ecosystems
Citation:
Jarvis, B. AND Y. Wan. Simulating Hypoxia and Acidification Dynamics in Pensacola Bay: Challenges Presented by Highly Dynamic Estuarine Ecosystems. Ocean Sciences Meeting 2024, New Orleans, LA, February 18 - 23, 2024.
Impact/Purpose:
This abstract is for a presentation to be given at the ASLO Ocean Sciences meeting 2024. The presentation will highlight field monitoring of low oxygen and acidification in Pensacola Bay as applied to development of a complex simulation model using EPA's Coastal Generalized Ecosystem Model. Results are the based on simulations and monitoring efforts developed under SSWR.405.2.3.3.
Description:
Increased nutrient loading to coastal ecosystems has fueled a series of intertwined water quality processes that leads to low dissolved oxygen (DO) or hypoxia (DO ≤ 2 mg L-1) and reduced pH, which is also known as nutrient enhanced acidification. While the cumulative impact of these two co-occurring stressors can result in more significant impacts to aquatic life than each stressor alone, they also present unique challenges to water quality modeling for assessing both carbonate and oxygen dynamics in coastal ecosystems. To address these challenges, we combine a robust water quality monitoring program in Pensacola Bay, FL with implementation of EPA’s Coastal Generalized Ecosystem Model (CGEM). The monitoring program identified unique spatial patterns of low DO and pH that varied over a period of hours to days and exhibit both prolonged and diel patterns. Such data collected with sufficient spatial scales and temporal frequencies are essential for complex water quality modeling, which often struggles to realistically simulate highly dynamic ecosystem processes at sub-daily timescales. In addition to the need of accurate hydrodynamic forcings for effective water quality model implementation, CGEM simulations also highlight the importance of effective model parameterization to evaluate DO and carbonate dynamics, particularly in shallow ecosystems where sediment processes play an important role in bottom water quality. Despite these challenges, improved water quality models such as CGEM for evaluation of oxygen and carbonate dynamics remain an invaluable tool that can be used to forecast future conditions in a changing climate and ecosystem response to management actions.