Coastal Wetland Restoration; What Is the Carbon Value ?.

The highly visible coastal phenomenon of wetland loss in coastal Louisiana will be examined through the prism of carbon accumulation and loss. Carbon storage or sequestration in the rapidly subsiding LA coastal marsh soils was based on vertical marsh accretion rates and aerial change data. Marshes sequester significant amount of carbon through vertical accretion however, large amounts of carbon, previously sequestered in the soil profile is lost through annual deterioration of these coastal marshes. Hurricanes, such as Katrina and Rita, have triggered instantaneous large carbon losses of sequestered soil carbon through the destruction of large areas of marsh. Our analysis shows proposed coastal restoration efforts will not be sufficient to restore carbon losses by storms and marsh deterioration, but do have some value in terms of slowing the rate of wetland loss and sequestering carbon.   Further, we have estimated the economic benefit of carbon sequestration for coastal wetland restoration efforts.  Results suggest that LA coastal marshes may not serve as a net sink of carbon.  The weltand loss rates in the subsiding LA coastal region may serve as a predictor of the impact of future predicted increasing global sea level rise on carbon sequestration for coastal regions worldwide.