[Personnel: Last_Name='RYAN', First_Name='KEN']
The effects of UVB on growth and productivity and photoadaptations of bottom ice algae at Cape Evans, McMurdo SoundEntry ID: K136_1999_2002_NZ_1
Abstract: Sea ice hosts a large community of algae which is released into the food chain when the ice melts. The sea ice algae grow rapidly in the Antarctic spring at a time that coincides with the ozone hole and when sea ice is most transparent to UVB. They are a good organism to study for the analysis of the effects of UVB on the Southern Ocean food chain. The changes in photosynthetic rate and the ... effects of UVB on the growth of sea ice algae was investigated at Cape Evans over several seasons by altering the UVB flux over four areas of sea ice providing plots of different UV treatment: 1) photosynthetically active radiation (PAR) only, 2) PAR + UVA, 3) PAR + UVA + UVB, and 4) PAR + UVA + enhanced UVB; in the second season, this plot was a control and was therefore ambient PAR + UVA + UVB. A light fitting with 6 UVB fluorescent tubes was set in a shallow trough cut in the ice to provide additional UVB radiance above ambient for plot 3 in season two as well. Samples from the bottom 100mm of ice cores were taken over two weeks, melted and analysed for changes in photosynthetic pigments, mycosporine like amino acids, total cell numbers, species composition and carbon, nitorgen and phosphorous content. A PUV500 submersible multichannel radiometer was used to measure UVB and visible radiation both above and beneath the ice. Oxygen microelectrodes were deployed under the ice. A CTD probe (conductivity, temperature and depth) was sent to the bottom of the bay (c. 35m) at 1pm each day. The probe records a profile of these physical parameters and also records chlorophyll levels of the phytoplankton in the water. Photosynthetic rates in situ were measured using PAM fluorescence techniques. It was used on small samples in the laboratory and was also deployed remotely under the ice. By taking measurements from early morning to midday, the adaptations the algae photosynthetic system made to the increasing radiation (photoacclimation) was observed and then as intensity passed through the maximum at solar noon, the delay in algal response to changing light intensity was measured.
Start Date: 1999-10-25Stop Date: 1999-11-15
Start Date: 2001-10-11Stop Date: 2001-11-09
TERRESTRIAL HYDROSPHERE > WATER QUALITY/WATER CHEMISTRY > CHLOROPHYLL
BIOLOGICAL CLASSIFICATION > BACTERIA/ARCHAEA
BIOLOGICAL CLASSIFICATION > PLANTS > MICROALGAE
BIOSPHERE > AQUATIC ECOSYSTEMS > PLANKTON > PHYTOPLANKTON
BIOSPHERE > AQUATIC ECOSYSTEMS > MARINE HABITAT
BIOSPHERE > ECOLOGICAL DYNAMICS > COMMUNITY DYNAMICS > BIODIVERSITY FUNCTIONS
BIOSPHERE > ECOLOGICAL DYNAMICS > ECOSYSTEM FUNCTIONS > PHOTOSYNTHESIS
BIOSPHERE > ECOLOGICAL DYNAMICS > ECOSYSTEM FUNCTIONS > PRIMARY PRODUCTION
Quality Existing samples are held at Victoria University of Wellington with a spreadsheet of sample numbers. All raw data is held by the investigators. Please contact Dr Ken Ryan for more information.
Data Set Progress
Phone: +64 4 463 6083
Fax: +64 4 463 5331
Email: ken.ryan at vuw.ac.nz
Victoria University of Wellington School of Biological Sciences PO BOX 600
Postal Code: 6140
Country: New Zealand
Role: DIF AUTHOR
Phone: +64 3 358 0200
Fax: +64 3 358 0211
Email: s.gordon at antarcticanz.govt.nz
Antarctica New Zealand Private Bag 4745
Country: New Zealand
Ryan, K.G. Hegseth, E.N. Martin, A. Davy, S.K. O’Toole, R. Ralph, P.J. McMinn, A. Thorn, C.J. 2006 Comparison of the microalgal community within fast ice at two sites along the Ross Sea coast, Antarctica. Antarctic science 18(4): 583-594 doi: 10.1017/S0954102006000629
Ryan, K.G., Ralph, P., and McMinn, A. 2004. Acclimation of Antarctic bottom-ice algal communities to lowered ... salinities during melting. Polar Biol. 27: 679-686.
McMinn, A. Ryan, K. Gademann, R. 2003 Diurnal changes in photosynthesis of Antarctic fast ice algal communities determined by pulse amplitude modulation flurometry. Marine biology 143: 359-367
Trenerry, L.J. 2003. Microsensor studies of sea ice algal primary production. MSc thesis, Institute of Antarctic and Southern Ocean Studies, University of Tasmania, Australia.
Ryan, K.G. McMinn, A. Mitchell, K.A. Trenerry, L. 2002. Mycosporine-like amino acids in Antarctic sea ice algae, and their response to UVB radiation. Zeitschrift fur Naturforschung 57(c): 471-477.
Trenerry, L.J. McMinn, A. Ryan, K.G. 2002. In situ oxygen microelectrode measurements of bottom ice algal production in McMurdo Sound, Antarctica. Polar biology 25: 72-80.
Trenerry, L.J. McMinn, A. Ryan, K.G. 2002. In situ oxygen microelectrode measurements of bottom ice algal production in McMurdo Sound, Antarctica. in: Ecological studies in the Antarctic sea ice zone: results of EASIZ midterm symposium.Arntz W. Clarke A.(eds) Berlin, New York: Springer-Verlag. pp.185-193
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Creation and Review Dates
DIF Creation Date: 2005-09-22
Last DIF Revision Date: 2009-03-16