Emergy evaluation of benthic ecosystems influenced by upwelling in northern Chile: Contributions of the ecosystems to the regional economy

Abstract

Emergy evaluations of three benthic ecosystem networks found in Mejillones, Antofagasta and Tongoy Bays, located on the coast of northern Chile, were carried out with the intent of documenting the contributions of these coastal ecosystems to the economy. The productivity of these bays is strongly influenced by the Humboldt Current System, as well as by the loss of upwelled flows that occurs during El Nino events. The results of the emergy evaluations were expressed as emdollars (EM$), a combined emergy-money measure that can be used to examine the equity of the emergy exchanges between fishermen and the buyers of the harvested algae and shellfish. In addition, an estimate of the total ecosystem services provided by these coastal ecosystems was made. The emdollar (Em$y−1) and the hypothetical monetary value (US$y−1) of the nitrate nitrogen upwelled constituted the highest inflow of emergy to all three benthic ecosystems. The empower density expressed as Em$m−2y−1 was highest in Mejillones Bay; however, the natural capital (biomass) of the ecological components (EM$m−2) was highest in Antofagasta Bay, where La Rinconada Marine Reserve is located. The relationship between the coastal zone system and the regional economic system was assessed using the emergy benefit after exchange, EBE, which showed that there were net gains to the overall welfare of the sellers in two regions, 3,280,000 Em$ to those in Mejillones Bay, and 34,000,000 Em$ to those in Tongoy Bay, but a net loss of 2,000,000 Em$ to the sellers of algae and shellfish harvested from Antofagasta Bay. By supplying a clearer picture of the equity of trade relationships for individual organisms, fisheries and bays, emergy evaluation can help develop and implement management strategies for the conservation and preservation of coastal ecosystems to ensure that they are sustainable in the future.