Forest fire induced impacts on phosphorus, nitrogen, and chlorophyll a concentrations in boreal subarctic lakes of northern Alberta P. McEachern, E.E. Prepas, J.J. Gibson, and W.P. Dinsmore Abstract: The biogeochemistry of 10 headwater lakes in burnt peatland–conifer catchments and 14 in unburnt cat...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.487.2535 http://www.science.uwaterloo.ca/~jjgibson/mypdfs/mceachern.pdf |
| Summary: | Forest fire induced impacts on phosphorus, nitrogen, and chlorophyll a concentrations in boreal subarctic lakes of northern Alberta P. McEachern, E.E. Prepas, J.J. Gibson, and W.P. Dinsmore Abstract: The biogeochemistry of 10 headwater lakes in burnt peatland–conifer catchments and 14 in unburnt catch-ments was evaluated throughout a summer 2 years following forest fire in a boreal subarctic region of northern Alberta. Cation exchange within burnt catchments resulted in proton flux and a 9 % reduction in mean pH. Lakes in burnt catch-ments contained more than twofold higher (P << 0.01) mean concentrations of total, total dissolved, and soluble reac-tive phosphorus, 1.5-fold higher (P << 0.01) concentrations of dissolved organic carbon, and more than 1.2-fold higher (P < 0.05) concentrations of total and total dissolved nitrogen, nitrate + nitrite, and ammonium compared with refer-ence lakes. Total phosphorus concentration explained 86 % of the variance in reference lake chlorophyll concentration but was not related to chlorophyll concentration in burnt lakes. Analysis of chlorophyll – total phosphorus residuals suggested that algae in burn-impacted lakes were light limited. With the addition of five lakes burnt between 1961 and 1985, time since disturbance and percent disturbance combined explained 74 % of the variance in total phosphorus among burnt lakes. Fire caused increased flux of materials to the study lakes with slow recovery over decades. |
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