Zooplankton and the Ocean Carbon Cycle.
Marine zooplankton comprise a phylogenetically and functionally diverse assemblage of protistan and metazoan consumers that occupy multiple trophic levels in pelagic food webs. Within this complex network, carbon flows via alternative zooplankton pathways drive temporal and spatial variability in production-grazing coupling, nutrient cycling, export, and transfer efficiency to higher trophic levels. We explore current knowledge of the processing of zooplankton food ingestion by absorption, egestion, respiration, excretion, and growth (production) processes. On a global scale, carbon fluxes are reasonably constrained by the grazing impact of microzooplankton and the respiratory requirements of mesozooplankton but are sensitive to uncertainties in trophic structure. The relative importance, combined magnitude, and efficiency of export mechanisms (mucous feeding webs, fecal pellets, molts, carcasses, and vertical migrations) likewise reflect regional variability in community structure. Climate change is expected to broadly alter carbon cycling by zooplankton and to have direct impacts on key species.
Virginia Institute of Marine Science, The College of William and Mary, Gloucester Point, Virginia 23062; email: debbies@vims.edu.
Deborah K
DK
Steinberg
Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093; email: mlandry@ucsd.edu.
Michael R
MR
Landry
D000818:Animals; D057486:Carbon Cycle; D057231:Climate Change; D020387:Food Chain; D009792:Oceans and Seas; D015048:Zooplankton
biological pump; climate change; efficiency; food web; metabolism