Title Summer variability, winter dormancy; lichen activity over 3 years at Botany Bay, 77S latitude, continental Antarctica
Author Schroeter, B.; Green, T.G.A.; Pannewitz, S.; Schlensog, M.; Sancho, L.G.
Author Affil Schroeter, B., University of Kiel, Biological Sciences, Kiel, Germany. Other: University of Waikato, New Zealand; Christian Albrechts Universitat, Germany; Universidad Complutense de Madrid, Spain
Source Polar Biology, 34(1), p.13-22. Publisher: Springer-Verlag, Berlin, Germany. ISSN: 0722-4060
Publication Date Jan. 2011
Notes In English. 46 refs. GeoRef Acc. No: 308835. CRREL Acc. No: 65006255
Index Terms biogeography; chlorophylls; ecology; lichens; Antarctica; Southern Ocean--Ross Sea; Botany Bay; chlorophyll; nutrients; organic compounds; pigments; porphyrins; productivity; Ross Sea; seasonal variations; Southern Ocean
Abstract Lichens make up a major component of Antarctic vegetation; they are also poikilohydric and are metabolically active only when hydrated. Logistic constraints have meant that we have little idea of the length, timing or environmental conditions of activity periods of lichens. We present the results of a three-year monitoring of the activity of the lichen Umbilicaria aprina at Botany Bay (77S latitude) in the Ross Sea region, continental Antarctica. Chlorophyll fluorescence parameters that allowed hydrated metabolic activity to be detected were recorded with a special fluorometer at 2- or 3-h intervals. Air and thallus temperatures and incident PPFD were also recorded at hourly intervals. Activity was extremely variable between months and years and, overall, lichen was active for 7% of the 28- month period. Spring snow cover often delayed the onset of activity. Whereas the period immediately after snow melt was often very productive, the later months, January to March, often showed low or no activity. Mean thallus temperature when active was just above zero degrees and much higher than the annual mean air temperature of -15 to -19C. Because major snow melts occurred when incident radiation was high, the lichen was also subjected to very high PPFD when active, often more than 2,500 mol photon m-2 s-1. The major environmental stress appeared to be high light rather than low temperatures, and the variability of early season snow fall means that prediction of activity will be very difficult.
URL http://hdl.handle.net/10.1007/s00300-010-0851-7
Publication Type journal article
Record ID 91244