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A regime shift from macrophyte to phytoplankton dominance enhances carbon burial in a shallow, eutrophic lake
- Source :
- Watershed Sciences Faculty Publications, Ecosphere, 4, Ecosphere, 4, 11
- Publication Year :
- 2013
- Publisher :
- Hosted by Utah State University Libraries, 2013.
-
Abstract
- Ecological regime shifts and carbon cycling in aquatic systems have both been subject to increasing attention in recent years, yet the direct connection between these topics has remained poorly understood. A four-fold increase in sedimentation rates was observed within the past 50 years in a shallow eutrophic lake with no surface in- or outflows. This change coincided with an ecological regime shift involving the complete loss of submerged macrophytes, leading to a more turbid, phytoplankton- dominated state. To determine whether the increase in carbon (C) burial resulted from a comprehensive transformation of C cycling pathways in parallel to this regime shift, we compared the annual C balances (mass balance and ecosystem budget) of this turbid lake to a similar nearby lake with submerged macrophytes, a higher transparency, and similar nutrient concentrations. C balances indicated that roughly 80% of the C input was permanently buried in the turbid lake sediments, compared to 40% in the clearer macrophyte-dominated lake. This was due to a higher measured C burial efficiency in the turbid lake, which could be explained by lower benthic C mineralization rates. These lower mineralization rates were associated with a decrease in benthic oxygen availability coinciding with the loss of submerged macrophytes. In contrast to previous assumptions that a regime shift to phytoplankton dominance decreases lake heterotrophy by boosting whole-lake primary production, our results suggest that an equivalent net metabolic shift may also result from lower C mineralization rates in a shallow, turbid lake. The widespread occurrence of such shifts may thus fundamentally alter the role of shallow lakes in the global C cycle, away from channeling terrestrial C to the atmosphere and towards burying an increasing amount of C.
- Subjects :
- 0106 biological sciences
010504 meteorology & atmospheric sciences
global carbon cycle
regime shift
CO2 emissions
01 natural sciences
Carbon cycle
calcite precipitation
submerged macrophytes
Phytoplankton
Dominance (ecology)
Regime shift
Ecosystem
14. Life underwater
GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries)
Ecology, Evolution, Behavior and Systematics
Institut für Biochemie und Biologie
0105 earth and related environmental sciences
Ecology
010604 marine biology & hydrobiology
temperate zone
trophic status
15. Life on land
6. Clean water
Macrophyte
Oceanography
13. Climate action
Benthic zone
Ecological Microbiology
Environmental science
sedimentation
Eutrophication
metabolism
Subjects
Details
- ISSN :
- 21508925
- Database :
- OpenAIRE
- Journal :
- Watershed Sciences Faculty Publications, Ecosphere, 4, Ecosphere, 4, 11
- Accession number :
- edsair.doi.dedup.....4bc9c1b1e90c2426f42bbceb0d856423