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Methane emissions from an Amazon floodplain lake: Enhanced release during episodic mixing and during falling water
| Content Provider | Semantic Scholar |
|---|---|
| Author | Engle, Diana L. Melack, John Michael |
| Copyright Year | 2000 |
| Abstract | Methane fluxes to the troposphere were measured inLake Calado, a dendritic floodplain lake located inthe central Amazon Basin. Methane concentrations inthe surface water of the lake were less than 0.5 µM during a period of high and rising water inApril and May, except when episodic, deep mixingoccurred and surficial concentrations reached as highas 4.8 µM. Diffusive fluxes ranged from ca.2–20 mg CH4 m−2d−1 (mean: 6.6 mg CH4 m−2d−1) normally, but increased up to 220 mg CH4 m−2d−1 during the passageof a rare cold front. During six weeks of risingwater, the volume-weighted methane content of the lakeincreased during periods of stable thermalstratification (accumulation rates ranging from16–1411 mg CH4 m−2d−1) and decreasedduring episodes of partial mixing (rates of decreaseranging from 63–1792 mg CH4 m−2d−1). Surface water methane concentrations during low andfalling water in September varied by more than anorder of magnitude (range, 0.3–9 µM), anddiffusive fluxes ranged from 3–158 mg CH4m−2d−1 (mean, 54 mg CH4 m−2d−1). During falling water in September, total methane flux from the lake to the troposphere measured with a floating chamber rangedfrom 53–328 mg CH4 m−2d−1 (mean, 163 mgCH4 m−2d−1). Ebullitive flux averaged 69% of total flux. Total methane flux was highest when thermal stratification was lost due to decreasing lake depth. |
| Starting Page | 71 |
| Ending Page | 90 |
| Page Count | 20 |
| File Format | PDF HTM / HTML |
| DOI | 10.1023/A:1006389124823 |
| Volume Number | 51 |
| Alternate Webpage(s) | https://page-one.springer.com/pdf/preview/10.1023/A:1006389124823 |
| Alternate Webpage(s) | https://doi.org/10.1023/A%3A1006389124823 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
