Ingestion of detritus by the lagoon pelagic community at Eniwetok Atoll

Abstract

The gut contents of Undinula vulgaris (a calanoid copepod) collected from Eniwetok lagoon consisted of about 95% detritus with only 2% of the gut material fluorescing as chlorophyll. That of Oikopleura longicaudata (a larvaccan) consisted of about 89% detritus with only 6% fluorescing as chlorophyll. By contrast, the gut contents of the calanoid copepod, Acartia tonsa, from Narragansett Bay, Rhode Island, consisted of about 34% detritus with 36% of the gut material fluorescing as chlorophyll. The remaining material in the gut of all these organisms included various microorganisms and diatom frustules. Plankton‐feeding fishes from behind a reef and island were found to have consumed both zooplankton and detrital algal fragments. The higher levels of particulate carbon and nitrogen in the lagoon, which had a lower C : N ratio than found in the incoming oceanic water, indicated that reef detritus enriches the lagoon environment.