Floating Aquatic Macrophytes Can Substantially Offset Open Water CO₂ Emissions from Tropical Floodplain Lake Ecosystems

Tropical floodplain lake ecosystems are recognized as important sources of carbon (C) from the water to the atmosphere. They receive large amounts of organic matter and nutrients from the watershed, leading to intense net heterotrophy and carbon dioxide (CO₂) emission from open waters. However, the...

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Bibliographic Details
Published in:Ecosystems (New York) 2016-06, Vol.19 (4), p.724-736
Main Authors: Peixoto, R. B., Marotta, H., Bastviken, D., Enrich-Prast, A.
Format: Article
Language:English
Subjects:
Aquatic ecosystems
Aquatic plants
Biomedical and Life Sciences
Carbon dioxide
Carbon dioxide emissions
Carbon fixation
Ecology
Ecosystems
Emissions
Environmental Management
Floating plants
Floodplains
Geoecology/Natural Processes
Hydrology/Water Resources
Lakes
Life Sciences
Organic matter
Original Articles
Plant Sciences
Water reuse
Zoology
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Summary:Tropical floodplain lake ecosystems are recognized as important sources of carbon (C) from the water to the atmosphere. They receive large amounts of organic matter and nutrients from the watershed, leading to intense net heterotrophy and carbon dioxide (CO₂) emission from open waters. However, the role of extensive stands of floating macrophytes colonizing floodplains areas is still neglected in assessments of net ecosystem exchange of CO₂ (NEE). We assessed rates of air-lake CO₂ flux using static chambers in both open waters and waters covered by the widespread floating aquatic macrophyte (water hyacinth; Eichornia sp.) in two tropical floodplain lakes in Pantanal, Brazil during different hydrological seasons. In both lakes, areas colonized by floating macrophytes were a net CO₂ sink during all seasons. In contrast, open waters emitted CO₂, with higher emissions during the rising and high water periods. Our results indicate that the lake NEE can be substantially over-estimated (fivefold or more in the studied lakes) if the carbon fixation by macrophytes is not considered. The contribution of these plants can lead to neutral or negative NEE (that is, net uptake of CO₂) onayearly basis. This highlights the importance of floating aquatic macrophytes for the C balance in shallow lakes and extensive floodplain areas.
ISSN:1432-9840
1435-0629
1435-0629
DOI:10.1007/s10021-016-9964-3