Keeping the Books for Environmental Systems: An Emergy Analysis of West Virginia

Emergy provides a general accounting mechanism that allows us to view the economy and the environment on the same income statement and balance sheet. This allows an auditor to verify the economic picture by checking it against a more complete representation of the flows and storages of real wealth as measured by emergy. In this study, we constructed emergy accounts for the state of West Virginia in 1997. The income statement showed annual production, consumption, and flows of emergy and dollars into and out of the state. The balance sheet evaluated the storage of emergy in some of the state's assets. Emergy indices were used to answer questions posed by managers and gain insight into the state's economic and environmental strengths and weaknesses. West Virginia has great wealth in nonrenewable resources (9E14 sej m-2 or 17 times the U.S. average). The investment ratio of emergy purchased outside to indigenous renewable and nonrenewable emergy was 2.2:1, which indicates a high potential for future development. However, the environmental loading ratio (14:1) was already 1.5 times higher than that found at an average location in the U.S. Twice as much emergy was exported as received and standard of living indicators showed that people have largely failed to benefit from their state's wealth. We propose that, just as in business, where decisions made using financial accounts ensure solvency; decisions governing the environment should be made based on an emergy accounting of activities, assets, and liabilities for the combined system of humanity and nature.     

Comparative survival of bay scallops in eelgrass and the introduced alga, Codium fragile, in a New York estuary

Eelgrass, Zostera marina, is generally regarded as the preferred habitat of bay scallops, but in some cases scallop populations have persisted or increased in areas lacking eelgrass. This suggests that some other substrate(s) may serve important ecological functions for bay scallops. One candidate is Codium fragile, a macroalgal species with which bay scallops are known to associate and in which we commonly find juvenile and adult bay scallops in eastern Long Island, New York. In this study, we examined whether survival of planted bay scallops differed in Codium, eelgrass, and Codium + eelgrass substrates at two sites during August and October of 2 years. Survival of tethered scallops and recoveries of live free-planted individuals varied with scallop size, planting season and year, but no differences were observed between the three substrates for a given scallop size and planting date. Crab (particularly Dyspanopeus sayi) and whelk predation were implicated as important causes of tethered scallop mortalities while emigration and removal by predators likely contributed to scallop losses. Densities of naturally recruited 0+ years scallops recovered by visual and suction dredge sampling were similar in the eelgrass and Codium substrates. While our results suggest that Codium may offer some degree of predation refuge for bay scallops, further work needs to weigh the potential disadvantages of this substrate (such as low DO levels, potential attachment and transport of scallops, and differences in current flow, food availability and sedimentation relative to eelgrass) to determine if Codium may serve as a valuable habitat for bay scallops throughout their lifespan.