Ecological implications of fecal pellets produced by the Antarctic krill Euphausia superba in the Antarctic Ocean

Organic analyses and electron microscopic observations on fecal pellets produced by the Antarctic krill Euphausia superba Dana showed that krill fed on choanoflagellates, the abundant heterotrophic flagellate in the Antarctic Ocean. Two new pathways of organic materials in the Antarctic ecosystem are proposed: (1) a new food chain including non-living particulate and dissolved organics, and bacteria-choanoflagellate-krill-vertebrate, which coexists with the traditional diatom-krill-vertebrate food chain; (2) non-phytoplanktonic organic materials in surface waters are transferred into choanoflagellates and are transported to deep water as fecal pellets which are still useful as nutrition for other organisms there.