Data Description

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Citation:
Smith, RIL (1988): Tab. 1: Mean water loss by mosses and lichens at 40%. doi:10.1594/PANGAEA.762952,
Supplement to: Smith, Ronald I Lewis (1988): 2.5 Aspects of cryptogam water relations at a Continental Antarctic Site. Polarforschung, 58(2/3), 139-153, hdl:10013/epic.29609.d001
Abstract:
The loss of water in a desiccating atmosphere (c.40% r.h. at 10°C) and uptake of water from a saturated atmosphere (100% r.h. at 10°C) was recorded at intervals over periods of many hours or days in the dominant mosses and macroiichens occurring near the Australian Casey Station. Wilkes Land, continental Antarctica. While major differences exist in the water holding capacity and rates of water loss between mosses and lichens, the minimum levels attained after prolonged exposure to desiccating conditions are remarkably similar. By contrast, the volume of water absorbed from a saturated atmosphere is very similar in both groups of cryptogams. Morphological and anatomical characters are responsible for many of the differences, both between species, and within species exhibiting different growth features. Thus, significantly larger amounts of water are held by colonies of Bryum algens with a dense tomentum of rhizoids than those with sparse rhizoids; similarly, the rhizinate Umbilicaria aprina held a greater volume of water than the erhizinate U. decussata. The filamentous mat form of Alectoria mimiscula permits a much higher water content to be attained than in the coarser fruticose forms of Usnea sphacelata and U. antarctica. The dense shoot arrangement in Schistidium antarcticum accounts for the high water holding capacity in the hydric turf form whereas the less densely packed shoots and thicker cell walls of the xeric cushion form maintain a lower water content. The rate of water loss (as percentage dry weight) was much faster in the turf form of Schistidium and tomenlose form of Bryum, although this trend was reversed when expressed as percentage of the initial water content. Minimal water contents arc achieved by the lichens in desiccating conditions within 6-12 hours, whereas the mosses take several times longer. The water relations characteristics of these cryptogams are considered in the light of their distribution in the field and of their metabolic activity under prevailing Antarctic conditions.
Coverage:
Latitude: -66.283000 * Longitude: 110.517000
Event(s):
Casey_Station * * Latitude: -66.283000 * Longitude: 110.517000 * Elevation: 30.0 m * Location: Vincennes Bay, Antarctica * * Device: Station *
Parameter(s):
#NameShort NameUnitPrincipal InvestigatorMethodComment
1Species *SpeciesSmith, Ronald I Lewis *
2Growth form *Growth formSmith, Ronald I Lewis *
3Water content of dry mass *Water dm%Smith, Ronald I Lewis *Calculated from weight/volume *initial
4Water content, standard deviation *Water std dev±Smith, Ronald I Lewis *initial
5Water loss per dry weight *-H2O dry wgt%Smith, Ronald I Lewis *Time 1 hr
6Water loss per dry weight *-H2O dry wgt%Smith, Ronald I Lewis *Time 6 hr
7Water loss per dry weight *-H2O dry wgt%Smith, Ronald I Lewis *Time 12 hr
8Water loss per dry weight *-H2O dry wgt%Smith, Ronald I Lewis *Time 24 hr
9Water content of dry mass *Water dm%Smith, Ronald I Lewis *Calculated from weight/volume *
10Water content, standard deviation *Water std dev±Smith, Ronald I Lewis *
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Size:
127 data points

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