Advances in Microbial Ecology

Volume 15 of the series Advances in Microbial Ecology pp 81-103

Roles of Submicron Particles and Colloids in Microbial Food Webs and Biogeochemical Cycles within Marine Environments

  • Toshi NagataAffiliated withOcean Research Institute, University of Tokyo
  • , David L. KirchmanAffiliated withCollege of Marine Studies, University of Delaware

* Final gross prices may vary according to local VAT.

Get Access


The recent discovery of numerous detrital submicron particles in diverse marine environments (Koike et al., 1990; Longhurst et al., 1992; Wells and Goldberg, 1991, 1994) has stirred the interest of oceanographers and has spurred studies into the roles of these small particles in marine food webs and biogeochemical fluxes. The abundance of non-living submicron particles (107–1010 particles ml−1) far exceeds the number of living particles of similar size dimensions, including phytoplankton, bacteria, and viruses (Koike et al., 1990; Wells and Goldberg, 1991; see Table I). Bulk chemical measurements have confirmed that the “colloidal fraction” (size, 0.001–1 μm) represents a large fraction (10–50%) of total “dissolved” organic carbon (DOC) in seawater (Ogawa and Ogura, 1992; Benner et al., 1992; Gau et al., 1994). Several provocative hypotheses have been proposed to explain the roles of colloids and submicron particles in trophic dynamics (Sherr, 1988; Flood et al., 1992), aggregate formation (Alldredge et al., 1993; Kepkay, 1994), and condensation of organic matter (Nagata and Kirchman, 1992b, 1996; Keil and Kirchman, 1994).