Carbon dioxide flux dynamics at the air-sea interface on the Louisiana continental shelf (Gulf of Mexico)
Continental shelf systems play an important role in the global carbon cycle, sequestering ~15-20% of net annual carbon dioxide in the oceans, and actively exchange CO2 between the sea and air. Researchers Huang et al. (2014) set out to study the spatial and temporal variability of CO2 flux dynamics on the Louisiana continental shelf.
They were able to determine strong spatial concentration gradients across the Louisiana continental shelf: inner and middle shelf areas acted as atmospheric CO2 sinks, while the outer shelf was near neutral.
They also found that pCO2 varied along a salinity gradient from the inner shelf towards the outer shelf, where the lowest values of pCO2 were seen in the mid salinity range (17 to 33 psu).
Seasonal patterns in the levels of surface pCO2 were also noted:
- undersaturated during spring, with respect to the air
- near atmospheric values in summer
- oversaturated in the fall
- near atmospheric values in the winter time
Overall, the north Gulf of Mexico acts as a sink for air-sea CO2, and variations seen were mainly due to biological processes, as well as physical mixing.
Given these spatio-temporal dynamics, meteorological changes due to the changing cimate have the potential to alter air-sea CO2 fluxes of global continental shelves.
Huang et al. (2015), “The carbon dioxide system on the Mississippi River-dominated continental shelf in the northern Gulf of Mexico: 1. Distribution and air-sea CO2 flux”