OA in nwGOM

The human society has had significant influence on the global ocean carbonate chemistry (aka ocean acidification or OA) through fossil fuel combustion, deforestation, and cement production over the past 250 years. In the coastal ocean however, other forcings such as continental nutrient input and physical oceanographic changes can have stronger impacts on both the magnitude of short-term variation and long-term trend in carbonate parameters (pH, carbonate saturation states). Among the NOAA designated Large Marine Ecosystems, the Gulf of Mexico (GOM) remains poorly understood in terms its current OA conditions, despite its ecological and economic significance. In the northwestern GOM (nwGOM), a decadal acidification has been observed in the shelf-slope region with the anthropogenic CO 2 contributing to a smaller fraction of CO 2 accumulation than that from metabolic production. This acidification effect is significantly greater than that in other tropical and subtropical areas. Unfortunately, whether the observed OA in this region represents a short-term phenomenon or a long-term trend is unknown. Given the fact that nutrient pollution through continental runoff is predicted to worsen due to enhanced hydrological cycle and that future upwelling may become stronger, both as a result of climate change, the nwGOM will likely experience more serious acidification while atmospheric CO 2 level keeps increasing. Collaborating with colleauges from NOAA Atlantic Oceanographic and Meteorological Laboratory, Texas A&M University, the Gulf of Mexico Coast Ocean Observing System, and Texas A&M University-Corpus Christi, we will investigate spatial and temporal changes in carbonate chemistry signals in the northwestern Gulf of Mexico for the optiminzation of ocean acidification monitoring effort in this region.