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Chapter 2 - Coastal EcosystemsTable 12-1 Valuation of salt marsh ecosystem services. Reprinted with permission from BrombergGedan et al. (2009).Ecosystem Service Examples of Human Benefits Average Value (Adj. 2007 $ a ha –1 year –1 )Disturbance regulation Storm protectio and shoreline protection $2824Waste Treatment Nutrient removal and transformation $9565Habitat/refugia Fish and shrimp nurseries $280Food Production Fishing, hunting, gathering, aquaculture $421Raw materials Fur trapping $136Recreation Hunting, fishing, birdwatching $1171TOTAL $14,397residential development, and industry) have altered andreduced the extent of marshes through diking, dredging,filling, and armoring.A comprehensive estimate of salt marsh loss along theeastern seaboard has not yet been produced and is beyondthe scope of this project. However, GIS methodsare increasingly being used to examine historical mapsto produce local and regional spatially explicit estimates.It has been estimated that Rhode Island salt marsh areahas been reduced by 53% since 1832 and that, since 1777,40% of Massachusetts salt marsh has been lost, withover 80% lost in the heavily filled Boston area estuary(Bromberg Gedan and Bertness 2005). At Great Bay,New Hampshire a comprehensive review of historical dataidentified likely locations of salt marsh loss (Figure 2-1).Results indicate that the current extent of salt marsh inthe Great Bay estuary is about 400 hectares and the identifiedrestoration opportunities total about 200 hectares(GBERC 2006).EelgrassEelgrass (Zostera marina) is the major seagrass in the westernNorth Atlantic, a marine flowering plant that growsin subtidal and intertidal regions of coastal waters in bothprotected and exposed systems. In addition to providingfood and critical spawning and refuge habitat for fish andinvertebrates (Wyda et al. 2002; Heck et al. 2003), thecomplex networks of leaves, roots, and rhizomes serve totrap nutrients and sediments, protect shorelines from erosion,and filter pollution. In northern latitudes eelgrasstypically exhibits a seasonal change in abundance, withlow biomass in winter months followed by rapid increasesin the spring and early summer (Short et al. 2007).Oysters and other shellfish benefit from associations witheelgrass in several ways. Eelgrass meadows trap and sequestersuspended sediments that might otherwise smotherjuvenile shellfish and reduce habitat quality for adults.The beds also create eddies in currents that can affectlarval retention and settlement, and the plants providepotential attachment sites for planktonic stages of someshellfish, notably bay scallops (Argopecten irradians) (Newelland Koch 2004).Northwest Atlantic Marine Ecoregional Assessment • Phase 1 Report 2-