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Carbon dioxide and submersed macrophytes in lakes: linking functional ecology to community composition.
- Source :
- Ecology; Dec2017, Vol. 98 Issue 12, p3096-3105, 10p
- Publication Year :
- 2017
-
Abstract
- Evaluating plant community response to atmospheric CO<subscript>2</subscript> rise is critical to predicting ecosystem level change. Freshwater lakes offer a model system for examining CO<subscript>2</subscript> effects as submersed macrophyte species differ greatly in their growth responses to CO<subscript>2</subscript> enrichment, and free CO<subscript>2</subscript> concentrations among these habitats show a wide range of natural, spatial variation. We determined free CO<subscript>2</subscript> concentrations in the water column and sediment porewater in littoral zones with pH < 6.0 in Adirondack Mountain (New York, USA) lakes, and derived a community CO<subscript>2</subscript> responsiveness index (CCRI) based on quantitative sampling of 15 submersed macrophyte communities coupled with greenhouse-derived growth responses to CO<subscript>2</subscript> enrichment of constituent species to test two hypotheses: (1) CCRI, which is higher for communities dominated by species with greater growth responses to CO<subscript>2</subscript> enrichment, is positively correlated to free [CO<subscript>2</subscript>] in the water column, and (2) in natural communities, the percent of sediment CO<subscript>2</subscript>-using species, which are relatively unresponsive to CO<subscript>2</subscript> enrichment, is negatively correlated to free [CO<subscript>2</subscript>]. A significant positive correlation ( P = 0.003) between our physiologically based CCRI and the concentration of free CO<subscript>2</subscript> in the water column supported our primary hypothesis that sites with higher levels of free CO<subscript>2</subscript> are dominated by species with greater growth responses to CO<subscript>2</subscript> enrichment. Our CCRI is also highly significantly correlated ( P < 0.001) to the first axis scores for the same vegetation data from polar ordination. Finally, the relative importance of species that use sediment CO<subscript>2</subscript> as a photosynthetic carbon source is significantly negatively correlated ( P = 0.029) with the concentration of free CO<subscript>2</subscript> in the water column. Our results indicate that natural variations in CO<subscript>2</subscript> levels are important determinants of submersed macrophyte community composition. Further, we demonstrate the utility of a physiologically-based index of community composition, our CCRI, as an ecologically valid measure of community response to CO<subscript>2</subscript>. [ABSTRACT FROM AUTHOR]
- Subjects :
- CARBON dioxide
ECOSYSTEMS
MACROPHYTES
PHOTOSYNTHESIS
PLANT physiology
Subjects
Details
- Language :
- English
- ISSN :
- 00129658
- Volume :
- 98
- Issue :
- 12
- Database :
- Complementary Index
- Journal :
- Ecology
- Publication Type :
- Academic Journal
- Accession number :
- 126530518
- Full Text :
- https://doi.org/10.1002/ecy.2030