Phytoplankton and hydrological succession in Omega and Taynaya Bays, eastern Antarctica
Metadata record for data from ASAC Project 2146
See the link below for public details on this project.
From the abstracts of the referenced papers:
Early season phytoplankton communities in both Omega and Taynaya Bays are characterised by diatoms sedimenting out of the overlying sea ice. Initial nitrate, phosphate and silicate levels are high and the bay waters are covered with ice and well mixed. In Taynaya Bay the ice cover is retained throughout the season while Omega Bay is free for 6-8 weeks. After ice break out in Omega Bay, the phytoplankton community changes from one dominated by diatoms to one dominated by the phtyoflagellates, Pyramimonas spp., Cryptomonas sp. and Gymnodinium sp. In Taynaya Bay the ice remained and even though phtyoflagellates became more common, diatoms still dominated. These differences in community composition result from differences in light climate, extent of stratification and nutrient levels.
Sediment cores from Abel and Platcha Bays, in the Vestfold Hills, east Antarctica, contain evidence for a local late Holocene increase in fast ice extent and a possible ice cap retreat at approximately 1750 yr BP, a similar time to the Chelnock Glaciation. Prior to this time both bays experienced periods of isolation that lead to changes in their diatom flora, C:N ratio, percentage of biogenic silica and total organic carbon. Three new diatom indices are proposed; the fast ice index, based on the proportion of benthic taxa and the snow index, based on the proportion of Berkelaya adeliense and Thalassiosira australis. These indices show strong relationships with the percentage of biogenic silica, total organic carbon and percentage sand. A weak relationship exists between the fast ice index and delta 13 C and no relationship with the C:N ratio.
The fields in these datasets are:
Date
Julian Day
Sample
Volume filtered (L)
Acetone Volume (ml)
Abs
Chlorophyll
Phytoplankton
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