期刊
ISME JOURNAL
卷 8, 期 10, 页码 2104-2115出版社
SPRINGERNATURE
DOI: 10.1038/ismej.2014.47
关键词
Antarctica; carbon allocation; gas exchange; lichens; life traits; net photosynthesis
资金
- New Zealand Foundation for Research
- Science and Technology (FRST)
- University of Waikato Vice Chancellor's Fund
- Department of Biological Sciences, University of Waikato
- FRST grant
- Understanding, valuing and protecting Antarctica's unique terrestrial ecosystems: predicting biocomplexity in Dry Valley ecosystems
- Spanish Education Ministry [POL2006-08405, CTM2009-12838-C04-01]
- DFG Schwerpunktprogramm [1158 (BU 666/11-1)]
- ERA-Net BiodivERsA program
- German Research Foundation (DFG)
- Austrian Science Fund (FWF)
- Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS)
- Spanish Ministerio de Economia y Competitividad (MINECO)
Biological soil crusts (BSC) are the dominant functional vegetation unit in some of the harshest habitats in the world. We assessed BSC response to stress through changes in biotic composition, CO2 gas exchange and carbon allocation in three lichen-dominated BSC from habitats with different stress levels, two more extreme sites in Antarctica and one moderate site in Germany. Maximal net photosynthesis (NP) was identical, whereas the water content to achieve maximal NP was substantially lower in the Antarctic sites, this apparently being achieved by changes in biomass allocation. Optimal NP temperatures reflected local climate. The Antarctic BSC allocated fixed carbon (tracked using (CO2)-C-14) mostly to the alcohol soluble pool (low-molecular weight sugars, sugar alcohols), which has an important role in desiccation and freezing resistance and antioxidant protection. In contrast, BSC at the moderate site showed greater carbon allocation into the polysaccharide pool, indicating a tendency towards growth. The results indicate that the BSC of the more stressed Antarctic sites emphasise survival rather than growth. Changes in BSC are adaptive and at multiple levels and we identify benefits and risks attached to changing life traits, as well as describing the ecophysiological mechanisms that underlie them.
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