Article,
Microclimate and Biomass in Communities of the Bryum Association on Ross Island, Continental Antarctica
The Bryologist, 77 (2): 109--127 (1974)
Abstract
Microclimatic data for a population of Bryum argenteum at Cape Armitage, Ross Island, indicate that from 8 December 1971 to 4 January 1972 relative humidity at ground level varied between a mean daily maximum of 87\% at night and a mean minimum of 46\% by day, while mean daily maximum and minimum values for intensity of incoming solar radiation were 0.69 and 0.03 cal/cm2/min respectively. Temperature showed greater diurnal fluctuation at ground level than in the air above or in the soil. Mean daily maxima at three points in the surface layers of B. argenteum turfs ranged from 8.8 to 10.5°C, compared with mean daily minima of -1.1 to -1.5°C, Less than 5\% of the individual temperature readings at moss level were above 13°C, and approximately 60\% of the readings were below 2.5°C. A comparison of microclimatic and physiological data for B. argenteum suggests that light intensity at Cape Armitage was normally above the saturation level for photosynthesis, whereas low temperatures may have reduced the mean net assimilation rate to ca. 28\% of that at the temperature optimum. An estimate of 252 g carbon/m2/year for the productivity of closed turf of B. argenteum was derived from these results, but this is considered to exceed the true value. Biomass estimates, obtained for six stands of the Bryum antarcticum and B. argenteum sociations from the loss on ignition of standard area cores, ranged from 938 g/m2 for one almost closed turf of B. antarcticum to only 5-17 g/m2 for more representative, open stands of both sociations.
