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- Hancke, Marnie, et al.
(författare)
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Genetic diversity of Monoporeia affinis in relationship to environmental and spatial factors in Sweden’s largest lakes
- 2012
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Ingår i: Fundamental and Applied Limnology. - : Schweizerbart. - 1863-9135. ; 181, s. 183–195-
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Tidskriftsartikel (refereegranskat)abstract
- The glacial relict species Monoporeia affinis undergoes pronounced population fluctuations in Sweden's three largest lakes, which may be due to multiple forms of environmental stress, including eutrophication and subsequent hypoxia. In this study, we use cytochrome c oxidase subunit I (COI) and 16srRNA (16 S) sequence data to assess the genetic diversity of this freshwater amphipod, and study their spatial and environmental correlates. The populations in the three lakes were genetically differentiated with haplotype diversity of the 16 S gene being lower in populations from Lake Malaren compared to those in Lake Vattern and Lake Vanern; however, a broad-scale spatial analysis did not detect significant spatial patterns in genetic diversity across the lakes. Within lakes, however, subtle spatial effects were detected in the form of a significant distance decay of genetic diversity in some lakes, highlighting the importance of considering different spatial scales for studying genetic diversity. From the environmental variables studied, a biologically relevant impact of both oxygen and total phosphorus levels on haplotype diversity levels was found, indicating the negative consequences of eutrophication on genetic diversity of M. affinis. Despite significant decreases and fluctuations in population sizes, the demographic history of M. affinis populations is best described by a model of constant population size over time, suggesting a sufficiently large effective population size.
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| 2. |
- Kirchner, Nina, et al.
(författare)
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A first continuous three-year temperature record from the dimictic arctic-alpine Lake Tarfala, northern Sweden
- 2021
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Ingår i: Arctic, Antarctic and Alpine research. - : Informa UK Limited. - 1523-0430 .- 1938-4246. ; 53:1, s. 69-79
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Tidskriftsartikel (refereegranskat)abstract
- Arctic lakes are exposed to warming during increasingly longer ice-free periods and, if located in glaciated areas, to increased inflow of meltwater and sediments. However, direct monitoring of how such lakes respond to changing environmental conditions is challenging not only because of their remoteness but also because of the scarcity of present and previously observed lake states. At the glacier-proximal Lake Tarfala in the Kebnekaise Mountains, northern Sweden, temperatures throughout the water column at its deepest part (50 m) were acquired between 2016 and 2019. This three-year record shows that Lake Tarfala is dimictic and is overturning during spring and fall, respectively. Timing, duration, and intensity of mixing processes, as well as of summer and winter stratification, vary between years. Glacial meltwater may play an important role regarding not only mixing processes but also cooling of the lake. Attribution of external environmental factors to (changes in) lake mixing processes and thermal states remains challenging owing to for example, timing of ice-on and ice-off but also reflection and absorption of light, both known to play a decisive role for lake mixing processes, are not (yet) monitored in situ at Lake Tarfala.
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