Impact of global change on the biogeochemistry and ecology of an Arctic freshwater system
| Autor: | William B. Bowden, Anne E. Hershey, John E. Hobbie, George W. Kling, Bruce J. Peterson, George W. Kipphut, W. John O'Brien, Linda A. Deegan, Neil D. Bettez |
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| Rok vydání: | 1999 |
| Předmět: |
0106 biological sciences
education.field_of_study Biomass (ecology) 010504 meteorology & atmospheric sciences biology Ecology 010604 marine biology & hydrobiology Population Biogeochemistry Grayling Oceanography biology.organism_classification 01 natural sciences Trout Earth and Planetary Sciences (miscellaneous) Environmental Chemistry Environmental science Hypolimnion education 0105 earth and related environmental sciences General Environmental Science Apex predator Trophic level |
| Zdroj: | Polar Research; Vol 18, No 2 (1999): Special issue: Proceedings of the International Symposium on Polar Aspects of Global Change; 207-214 |
| ISSN: | 1751-8369 |
| DOI: | 10.3402/polar.v18i2.6576 |
| Popis: | Lakes and streams in the foothills near Tookik Lake, Alaska, at 68°N have been studied since 1975 to predict physical, chemical and biological impacts of future global change. Experimental manipulations include whole lake and continuous stream fertilization as well as removal and addition of predators (copepods, lake trout, grayling, sculpin). Based on our evidence the following scenario is likely. Warming thaws the upper layers of permafrost and streams and lakes become enriched with phosphorus. Streams respond quickly with higher production of diatoms but animal grazers keep biomass changes to a minimum. Fish productivity also increases. If phosphorus levels are too high, mosses become the dominant primary producer and sequester all of the nutrients. Growth of Arctic grayling under the present conditions only occurs in summers with higher than average stream flow. The present population would be stressed by warmer temperatures. When higher phosphorus levels reach lakes and cause slight europhication, the number of trophic levels will increase, especially within the microbial food web. Warmer lake temperatures increase stratification and, combined with eutrophication, could decrease oxygen in the hypolimnion. Oxygen levels will also decrease in winter under the ice cover. Eventually this habitat change will eliminate the lake trout, a top predator. Removal of lake trout results in a striking increase in abundance and productivity of smaller fish, including small lake trout, and the emergence of burbot as an alternate top predator. Large species of zooplankton will become virtually extinct. |
| Databáze: | OpenAIRE |
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