Ecosystem services: Nitrogen removal

High water quality (low nutrient loading) in the Virginia coastal bays has supported the continued expansion of restored seagrass meadows since 2001. However, land-use changes along the Eastern Shore, including the expansion of poultry farming and tomato plasticulture as well as increased residential development, are predicted to increase nutrient loads to the coastal bays. The restored seagrass meadows may play a critical role in buffering these increased nutrient loads by enhancing nitrogen removal compared to unvegetated sediments.

I measured N removal processes in the restored meadow to assess the magnitude of the nutrient buffer. N burial was the dominant removal process and was greater than current N loading from the watershed. In future scenarios, with higher rates of N loading due to changes in agriculture, expansion of the seagrass meadows would continue to offset increases in N loading. The seagrass meadow thus provides a valuable ecosystem service of nitrogen removal, under current and future conditions.

Removal and retention of nitrogen within the seagrass meadow provides an important ecosystem service that helps maintain high water quality.