Rates of carbonate dissolution in permeable sediments estimated from pore-water profiles: The role of sea grasses uri icon

abstract

  • In this study we estimate sediment carbonate dissolution rates for sandy sea grass sediments on the Bahamas Bank using an inverse porewater advection/diffusion/reaction model constrained by field observations. This model accounts for sea grass O2 input to these sediments, and also parameterizes porewater advection through these permeable sediments as a nonlocal exchange process. The resulting rates of carbonate dissolution are positively correlated with sea grass density, and are comparable with previous rate estimates for Florida Bay sediments. In contrast, the advective uptake of O2 by these sediments decreased with increasing sea grass density. This suggests that the competing interplay between bottomwater flow, nearseabed pressure gradients, and the presence of a sea grass canopy is important in controlling this type of sediment oxygen uptake. When the carbonate dissolution rates estimated here are examined in the context of carbonate budgets for shallowwater carbonate platforms systems, they suggest that carbonate dissolution may be a significant loss term in these budgets. Sea grassmediated carbonate dissolution may also exert a negative feedback on rising atmospheric CO2, although the magnitude of this effect remains to be quantified.

published proceedings

  • LIMNOLOGY AND OCEANOGRAPHY

author list (cited authors)

  • Burdige, D. J., Zimmerman, R. C., & Hu, X.

publisher