Bacterioplankton: a sink for carbon in a coastal marine plankton community
Recent determinations of high production rates (up to 30% of primary production in surface waters) implicate free-living marine bacterioplankton as a link in a microbial loop that supplements phytoplankton as food for herbivores. An enclosed water column of 300 cubic meters was used to test the microbial loop hypothesis by following the fate of carbon-14-labeled bacterioplankton for over 50 days. Only 2% of the label initially fixed from carbon-14-labeled glucose by bacteria was present in larger organisms after 13 days, at which time about 20% of the total label added remained in the particulate fraction. Most of the label appeared to pass directly from particles smaller than 1 micrometer (heterotrophic bacterioplankton and some bacteriovores) to respired labeled carbon dioxide or to regenerated dissolved organic carbon-14. Secondary (and, by implication, primary) production by organisms smaller than 1 micrometer may not be an important food source in marine food chains. Bacterioplankton can be a sink for carbon in planktonic food webs and may serve principally as agents of nutrient regeneration rather than as food.
- Research Organization:
- Univ. of Maryland, Cambridge
- OSTI ID:
- 5327852
- Journal Information:
- Science (Washington, D.C.); (United States), Vol. 235
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBON
MINERAL CYCLING
SINKS
AQUATIC ECOSYSTEMS
BACTERIA
BIOLOGICAL FUNCTIONS
CARBON 14
NUTRIENTS
TRACER TECHNIQUES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON ISOTOPES
ECOSYSTEMS
ELEMENTS
EVEN-EVEN NUCLEI
FUNCTIONS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MICROORGANISMS
NONMETALS
NUCLEI
RADIOISOTOPES
YEARS LIVING RADIOISOTOPES
520100* - Environment
Aquatic- Basic Studies- (-1989)
520302 - Environment
Aquatic- Radioactive Materials Monitoring & Transport- Aquatic Ecosystems & Food Chains- (-1987)