Functional dynamics of the microbial loop in saline lakes of the Vestfold Hills

Metadata record for data expected from ASAC Project 919.
See the link below for public details on this project.

The plankton dynamics of Ace Lake, a saline, meromictic basin in the Vestfold Hills, eastern Antarctica was studied between December 1995 and February 1997. The lake supported two distinct plankton communities; an aerobic microbial community in the upper oxygenated mixolimnion and an anaerobic microbial community in the lower anoxic monimolimnion. Phytoplankton development was limited by nitrogen availability. Soluble reactive phosphorus was never limiting. Chlorophyll a concentrations in the mixolimnion ranged between 0.3 and 4.4 micrograms per litre during the study period and a deep chlorophyll maximum persisted throughout the year below the chemo/oxycline. Bacterioplankton abundance showed considerable seasonal variation related to light and substrate availability. Autotrophic bacterial abundance ranged between 0.02 and 8.94 x 10 to the 8 per litre and heterotrophic bacterial abundance between 1.26 and 72.8 x 10 to the 8 per litre throughout the water column. the mixolimnion phtyoplankton was dominated by phytoflagellates, in particular Pyramimonas gledicola. P. geldicola remained active for most of the year by virtue of its mixotrophic behaviour. Photosynthetic dinoflagellates occurred during the austral summer, but the entire population encysted for the winter. Two communities of heterotrophic flagellates were apparent; a community living in the upper monimolimnion and a community living in the aerobic mixolimnion. Both exhibited different seasonal dynamics. The cliliate community was dominated by the autotroph Mesodinium rubrum. The abundance of M. rubrum peaked in summer. A proportion of the population encysted during winter. Only one other ciliate, Euplotes sp., occurred regularly. Two species of Metazoa occurred in the mixolimnion; a calanoid copepod (Paralabidocera antarctica) and a rotifer (Notholca sp.). However, there was no evidence of grazing pressure on the microbial community. In common with most other Antarctic lakes, Ace Lake appears to be driven by 'bottom-up' forces.

The fields in this dataset are:
Ace Lake
Aerobic monimolimnion
Ammonia
Ammonium
Ash free dry weight
Autotrophic Bacteria
Bacterial Production Leucine
Bacterial Production Thymidine
Biomass
Carbon
Cell
Chlorophyll a
Concentration
Copepods
Date
Date Code
Depth
Diatoms
Dinoflagellates
Dissolved Organic Carbon
Dissolved Oxygen
Doubling
Generation Time
Heterotrophic Bacteria
Heterotrophic Nanoflagellates
Ice Thickness
Intrinsic Growth Rate
Julian Day
Julian Month
Mesodinium rubrum
Mesodinium rubrum cysts
Mixolimnion
Monimolimnion
Nauplii
Nitrate
Nitrite
Notholca sp.
Other Ciliates
Oxygenated strata
Paralabidocera antarctica copepodid
Paralabidocera antarctica naupliar
Particulate Organic Carbon
Phosphate
Phototrophic Nanoflagellates
Salinity
Season
Soluble Reactive Phosphorus
Total Ciliates
Water Temperature