Year: 1990
Type: article
Abstract: Bacterial abundance and biomass were extensively measured in the euphotic zone at several oligotrophic and mesotrophlc sites of coastal and open Pacific ocean during different seasons.Cornpansons with phytoplankton biomass and l a t h particulate organic carbon (POC) were made in order to determine the quantitative significance of bacteria as a carbon and nitrogen pool in the euphotic zone.Analysis of our data and that from the literature showed that bacterial abundance in the euphotic zone has a lower threshold of ca 3 X 105 1111-' or 6 pg C 1-' Consequently, with increasingly oligotrophic condit~ons photoautotrophic bion~ass may decrease well below the bacterial b~omass.In oligotrophic waters bacterial biomass was comn~only 2 to 3 times greater than phytoplankton biomass.In contrast, In mesotrophic to eutrophic waters bactenal biomass was generally much less than phytoplankton biomass.Cornpanson w ~t h total POC (which included bacterial carbon) showed that in o l ~g o t r o p h ~c waters bacterial b ~o m a s s averaged 40 % (range 26 to 62 '6) of POC inexplicably, the sum of bacterial carbon and phytoplankton carbon was always about one-half of POC The dominance of bacterial biomass over phytoplankton biomass in oligotrophlc oceans has sign~ficant impl~cations for the food-web structure, nutr~ent cycling pathways, and for s i n l n g flux of organic matter Future studies should examine the physiological and trophic mechan~sms which lead to the dominance of bacterial biomass in oligotrophlc systems but of photoautotrophic biomass In the e u t r o p h ~c systems
Source: Marine Ecology Progress Series
DOI: 10.3354/meps063253
Authors: BC Cho, F Azam
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Life below water
Open Access status: bronze
OpenAlex ID: W2018348179