You are here:
Predicted effects of climate change on northern Gulf of Mexico hypoxia
Citation:
Lehrter, J., D. Ko, L. Lowe, B. Jarvis, B. Herchenroder, L. Olszyk, B. Penta, C. Le, AND D. Beddick. Predicted effects of climate change on northern Gulf of Mexico hypoxia. Bays & Bayous Symposium 2014, Mobile, AL, December 02 - 04, 2014.
Impact/Purpose:
The purpose is to investigate via numerical modeling the potential impacts on hypoxia by a future climate change scenario. The future scenario is developed from the IPCC (2014) report and other published literature.
Description:
U.S. state and federal partners are working cooperatively to develop nutrient management strategies to reduce hypoxia (O2 < 63 mmol m-3) in the northern Gulf of Mexico. Numerical models that represent eutrophication and hypoxia development processes have been an important tool for estimating the reduction of nutrient loads required to achieve management goals. The models, however, have not examined the potential role of climate change in altering how northern Gulf ecosystems respond to nutrient loads. In this study, we used a coastal ocean ecosystem model to assess a potential future climate of + 3°C air temperature and + 10% river discharge to inspect how future climate could impact hypoxia in the northern Gulf. We applied the model to the Louisiana shelf hypoxic area as influenced by the runoff from the Mississippi River basin. The net effect of increased temperature and freshwater discharge was an increase in the strength of water-column stratification at the pycnocline and a shallowing of the depth of the pycnocline. This change in the physical regime allowed a larger drawdown of O2 in the water-column beneath the pycnocline compared to the present climate mainly due to less mixing of O2 to depth. The implications resulting from this future climate scenario are that stricter nutrient management practices may be required to offset climate impacts and that without these practices northern Gulf estuarine and coastal systems may experience more frequent and longer duration hypoxia than in the present.