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The adaptation of cyanobacterial mats from the McMurdo Ice Shelf, Mt Discovery and the Alph River system to Antarctic environmental extremes

Entry ID: K081_1990_1991_NZ_1

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Summary

Abstract: The microbial adaptations of the cyanobacterial mats of the ponds of the McMurdo Ice Shelf to the environmental extremes experienced at this location, including changes in temperature and salinity, dehydration-rehydration cycles, low nitrogen: phosphorous ratios and high UV radiation was investigated. The fieldwork was mainly experimental with comparisons made between other pond systems from the ... McMurdo Sound area including Mt. Discovery - Minna Bluff and Pyramid Trough (Alph River) areas and from as far south as latitude 80°, the Darwin Glacier region. The Mt Discovery and Darwin Glacier regions underwent a limnological survey where ponds were sampled for conductivity, pH, temperature, size, discharge (L/s), depth, ion content (sodium, potassium, calcium, magnesium, chloride and sulphate), DRP, DOP, NH4, NO3, DON, benthic biomass and species composition. At Bratina Island, 12 ponds were studied at weekly intervals for water quality parameters (relative water level, sediment and water temperature, pH, DIC, conductivity, DRP, DOP, NH4, NO3, DON) and chlorophyll a concentrations. In addition, samples of water and dissolved gases were collected from around and below the benthic mats for dissolved gas composition (CO2, CH4 and N2O) and nutrient composition. The microbial adaptation to extreme Antarctic environments (low temperature/high salinity) was studied from a number of different physiological responses including biochemical adaptations (biochemical mechanisms of membrane lipid composition), the photosynthetic responses and changes in nitrogen fixation rates. A series of four experiments designed to examine the physiological responses of the benthic mats to the prevailing and extreme conditions which occur each year including response to extremes of salinity and temperature, short-term dehydration, ambient UV radiation and nutrient conditions were completed. The effects of salinity on mat metabolism by creating a salinity gradient and measuring nitrogen fixation, photosynthesis and respiration rates. A long term aim of research on these communities is to define the light-capturing and light screening properties of the microbial communities which dominate this and other freshwater ecosystems. To meet this aim, HPLC analysis of microbial communities in the Alph River-Trough Lake region was carried out to evaluate the changes in pigment composition as a function of UVA and UVB manipulations and as a response to desiccation and salinity changes.

Related URL

Link: VIEW PROJECT HOME PAGE

Geographic Coverage

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Spatial coordinates

N: -78.0

S: -78.0

E: 165.33

W: 165.33

Temporal Coverage

Start Date: 1990-12-29

Stop Date: 1991-01-27

Location Keywords

CONTINENT > ANTARCTICA

CONTINENT > ANTARCTICA > MCMURDO ICE SHELF

Science Keywords

BIOSPHERE > TERRESTRIAL ECOSYSTEMS > WETLANDS

TERRESTRIAL HYDROSPHERE > WATER QUALITY/WATER CHEMISTRY > CHLOROPHYLL

ISO Topic Category

CLIMATOLOGY/METEOROLOGY/ATMOSPHERE

ELEVATION

Access Constraints The data available can be licensed on an annual basis or by a once-off
payment. For research projects, this fee is usually waived and just a
handling charge is payable.

Use Constraints In line with Natural Environment Research Council policy, the
provision of its own data confers only a right to use the
data. Ownership of the data, or the associated Intellectual Property
Rights, will not normally be transferred. Data received from the
Institute of Hydrology must not be sold, or passed on to any third
party, but reproduction is permitted for the purposes of any fair
dealing in the course of study, research, public debate of
instruction, providing the source is acknowledged.

Ancillary Keywords

NERC

Originating Center

NERC/IH

Data Center

Center for Ecology and Hydrology, Wallingford, Natural Environment Research Council, UK

Data Center URL: http://www.nwl.ac.uk/ih/

Data Center Personnel
Name: DAVID MORRIS Phone: +44 (0)1491 692428 Fax: +44 (0)1491 692424 Email: dgm at ceh.ac.uk Contact Address: CEH Wallingford Maclean Building Crowmarsh Gifford Wallingford Oxfordshire OX10 8BB Country: UNITED KINGDOM

Personnel

MELANIE F. MEAUX

Role: DIF AUTHOR

Email: gsfc-gcmduso at mail.nasa.gov

Creation and Review Dates

Last DIF Revision Date: 2009-04-27

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