Anthropogenic Effects on Ecosystem Services as Mediated by Ocean Biogeochemical Processes

Anthropogenic activities influence a suite of oceanic properties, including temperature, circulation patterns, nutrient distributions and atmospheric and fluvial inputs, and changes in these properties may be local or global in scale. Consequently, anthropogenic activities potentially affect biogeochemical processes and fluxes that influence marine food webs and ecosystem services, and the effect varies with the magnitude and type of impact, ocean region and food web type. Primary production (PP) in the ocean has five principal fates: carbon export and sequestration (E), heterotrophic respiration (R), and production of microbes (M), zooplankton (Z) and harvestable marine resources, (i.e. fisheries; F); i.e. PP = E + R + M + Z + F. At steady state all M, Z and F is recycled and channeled toward R or E. However since the generation times of M and Z are short relative to F, steady state for M and Z is achieved sooner. Hence for this steady state condition, PP = E + R + F and F is typically small relative to R and E. These fluxes vary across large spatial scales and ocean basins, thus assessing or predicting impacts are difficult from models that are parameterized at global scales. Moreover many models predicting F from PP have large uncertainties. We propose that the carbon flux to F represents a 'leakage' from, and inefficiency in the ocean carbon pumps that regulate E. Here we report on a meta-analysis of the inter-relationships among PP, E and F with respect to the current estimates of the magnitude of the biologically mediated carbon pumps.