Microbial exopolymer secretions in ocean environments: their role(s) in food webs and marine processes
Decho, A.W. (1990). Microbial exopolymer secretions in ocean environments: their role(s) in food webs and marine processes, in: Barnes, H. et al. Oceanogr. Mar. Biol. Ann. Rev. 28. Oceanography and Marine Biology: An Annual Review, 28: pp. 73-153
In: Barnes, H. et al. (1990). Oceanogr. Mar. Biol. Ann. Rev. 28. Oceanography and Marine Biology: An Annual Review, 28. Aberdeen University Press: Aberdeen. ISBN 0-08-037981-8; e-ISBN 0-203-01480-4. 549 pp., more
In: Oceanography and Marine Biology: An Annual Review. Aberdeen University Press/Allen & Unwin: London. ISSN 0078-3218; e-ISSN 2154-9125, more
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| Keywords |
Biology > Microbiology
Food webs
Polymers
Secretion
Marine/Coastal |
| Abstract |
Microbial exopolymers are high molecular-weight mucous secretions of bacteria and microalgae. They range from tight capsules which closely surround cells to the loose-slime matrix associated with aggregates, sediment, detritus, and other surfaces. By virtue of their physical properties, exopolymers are highly adsorptive, and readily sequester dissolved organic matter and metals. Exopolymers are largely polysaccharide in composition, and can exist in 'dissolved' and 'particulate' form. These secretions serve many functions which enhance the survival and competitive success of microbial cells under natural conditions. While they have been well studied in other disciplines, the investigation of exopolymers in marine systems has been largely overlooked. Accumulating evidence, however, suggests that they influence a wide range of marine processes such as aggregate formation in the water column, benthic larval settlement, microscale biogeochemical processes, sediment stability, and metal sequestering by hydrothermal vent bacteria. In addition, when microbial consumers feed they coincidentally ingest exopolymers (and their adsorbed compounds). These secretions may, therefore, represent an effective vehicle to transfer nutrients and metals through lower marine food webs. This suggests a dynamic role for exopolymers in marine systems. As ocean paradigms are further revised, the potential roles of these secretions must certainly be addressed.The present review examines the properties, processes, and methodologies pertinent to the study of microbial exopolymers in ocean systems. Literature has been purposefully cited from various other disciplines where exopolymer-related processes have been well studied. A focus is made on attempting to understand the interactive roles of these secretions in food webs and other marine processes. |
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