Antarctic benthic and sea-ice microalgal interactions: food chain processes and physiology
Annual sea-ice in McMurdo Sound is known to provide an extensive microhabitat for microalgae containing a high biomass within the lower 5 cm at the water/ice interface, with an estimated annual production of 4.1 g of carbon/m/sup 2/. Upon senescence, this microalgal population contributes a large amount of C to the benthic biota. Total biomass as measured by membrane phospholipids of benthic microorganisms from three sites in McMurdo Sound were comparable to those of a Florida estuary and greater than those of deep-sea trenches. In addition to total biomass, changes in community structure of the sediments at the McMurdo study sites of Cape Evans, Cape Armitage, and New Harbor are detectable by detailed fatty-acid profiles of phospholipid membranes. These data are comparable to studies of the benthic macrofauna from McMurdo Sound which indicated that the east Sound sites are more productive than the west. The east Sound sediment sites were found to contain the greatest amount of the phospholipid fatty acid which is a major component of the sea-ice diatom Nitzschia cylindrus. Bacterial biomarkers indicated little difference in total biomass between the sites but did reveal community structure differences. Saturated, branched, and odd carbon fatty acids, were present in similar relative proportions. Fatty acids from triglyceride and sterols from the neutral lipid fractions of the sediments indicated a similar pattern to that of the phospholipid biomasses, with the east Sound sites containing greater amounts. Metabolic activities at the sites were measured by their incorporation of radiolabeled precursors into bacterial DNA and lipid classes. Lipid and metabolic activity monitoring has proven to be a useful technique in ice algal physiology studies.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- OSTI ID:
- 6969991
- Journal Information:
- Antarct. J. U.S.; (United States), Journal Name: Antarct. J. U.S.; (United States) Vol. 21:5; ISSN AJUSA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ALGAE
ANTARCTIC REGIONS
ANTARCTICA
BIOMASS
CARBOXYLIC ACIDS
CHROMATOGRAPHY
COMPARATIVE EVALUATIONS
DIATOMS
ENERGY SOURCES
ESTERS
GAS CHROMATOGRAPHY
HABITAT
HYDROGEN COMPOUNDS
ICE
LIPIDS
MASS SPECTROSCOPY
METABOLISM
MONITORING
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHOLIPIDS
PHYSIOLOGY
PLANTS
POLAR REGIONS
PRODUCTIVITY
RENEWABLE ENERGY SOURCES
SEAWATER
SEDIMENTS
SEPARATION PROCESSES
SPECTROSCOPY
WATER