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Chapter 2 - Coastal EcosystemsFigure 2-1. Estimated salt marsh loss at Great Bay, New Hampshire. This image shows the detail of a map from the Great BayEstuarine Restoration Compendium (2006). Dark orange indicates areas of probable loss identified using comparison of mapsfrom 1918 with modern survey data showing current salt marsh distribution (beige areas).In the North Atlantic, a wasting disease first noted inthe 1930s caused a rapid coastwide decline in the extentof eelgrass. The link between the disease and the marineslime mold Labrynthula zosterae is now well established(Den Hartog 1989; Muehlstein et al. 1991). It is thoughtthat higher than average salinity and human impacts onseagrass systems facilitated the disease.Despite the widespread loss of the great majority of theeelgrass along the Northwest Atlantic coast, many eelgrassbeds recovered over the subsequent few decades. However,this recovery coincided with rapidly increasing nutrientand sediment loads to coastal ecosystems, minimizingrecovery in some areas and leading to the eventual loss ofthousands of hectares of eelgrass beds that had briefly returnedfollowing the disease outbreak (Orth et al. 2006;Wazniak et al. 2007). Because of its functional role2-Northwest Atlantic Marine Ecoregional Assessment • Phase 1 Report