Quantifying interior coastal marsh degradation at two North Carolina marshes

Marshes along the coast of North Carolina are currently at risk due to ongoing land loss, and as they are highly productive waterways, understanding the processes driving land loss is critical. By focusing on two marshes adjacent to waterways — Roanoke Marsh, south of Manns Harbor, and Mackay Island National Wildlife Refuge — we created a dataset of land loss rates from 1983 to 2016, both within the marsh interior (due to expanding ponds) and on the outer edge of the marsh (coastal retreat). We investigated the hypothesized primary driver behind the interior pond expansion (wind-driven waves in the pond interior) and the coastal edge retreat of the marsh (wind-driven waves within Currituck Sound). The total land area lost over the 34- year study period was 1.49 km2 and 2.32 km2 on Roanoke Marsh and Mackay Island, respectively. The percentage of total land lost due to internal pond expansion was 60% in Roanoke Marsh and 44% in Mackay Island. Internal pond expansion is at least of equal importance to outer coastal retreat for net land loss in these coastal marshes. The local wind has a dominant direction from the north-northwest with more energetic winds during the winter. However, the wind directions and direction of pond expansion do not appear to be correlated. This may be because the winds are bimodal and drive expansion in multiple directions. In addition, there is subsidence in this portion of North Carolina that may be an additional factor contributing to the pond area expansion.

Nematode Community Structure and Biodiversity in Relation to Submerged Aquatic Vegetation at Currituck Sound, North Carolina

Submerged Aquatic Vegetation (SAV) in coastal habitats plays critical roles because it protects coastlines, prevents erosion, provides nursery habitat, and dissolved oxygen. Meiobenthic communities in these habitats also play a key role in ecosystems processes. However, currently SAV loss continues unabated globally. Our understanding of the impact this loss has on meiobenthic communities is limited. To assess the impact of SAV cover on nematode communities, we studied nematode communities at Currituck Sound, NC, by comparing communities at an unvegetated and at an SAV site. Nematodes were identified to genus level morphologically. Our results showed that general diversity was low compared to other comparable sites with only 10 genera at both sites. Diversity and community structure were distinct at the two sites indicating that submerged aquatic vegetation may impact community structure of nematodes.