Phytoplankton growth, microzooplankton grazing, and carbon cycling in marine systems

摘要: We present an analysis of the global impact microplanktonic grazers on marine phytoplankton and its implications for remineralization processes in microbial community. The data were obtained by extensive literature search that yielded 788 paired rate estimates autotrophic growth (mu) microzooplankton grazing (m) from dilution experiments. From studies which standing stock was measured terms carbon equivalents, we show production estimate experiments is a reasonable proxy (r = 0.89) determined standard C-14 method. ratio m: mu, proportion primary (PP) consumed micrograzers, shows consumption main source mortality oceans, accounting 67% daily full set. This varies modestly among various habitats regions, with averages ranging 60% coastal estuarine environments to 70% open similar to59% temperate-subpolar polar systems 75% tropical-subtropical regions. Given metabolic requirements micrograzers assuming they consume most bacterial production, regionally averaged protistan respiration are 35-43% PP first level consumer or 49-59% three trophic transfers. estimated contributions total community same magnitude as respiration. Consequently, potential ecosystem differences micrograzer activity structure large uncertainty biogeochemical models seek predict role cycling parameters alone.