This report aimed to investigate how chlorophyll-concentrations (Chl-a) in the water column and varved sediments were affected by changes in air temperature and precipitation and consequently how climate change will affect the sedimentation and productivity in boreal aquatic ecosystems. VRS (visible-reflectance-spectroscopy) was used to asses Chl-a and its derivates in sediment trap samples between 2002-2021 and in a series of freeze cores (1979-2021) from lake Nylandssjön, with annually laminated sediments. In order to evaluate how weather and climate change affected the sedimentation and productivity in the lake the results were compared with meteorological data from SMHI (Swedish Meteorological and Hydrological Institute) and Chl-a data from seperate depths in the water column. The results indicate that the majority of the yearly sedimentation occur either in May or June, where a higher cumulative amount of precipitation in May lead to a higher sedimentation rate in May (r=0,49; p=0,03). The amount of precipitation in spring also had a significant impact on the primary production in spring and summer (r=0,59; p=0,01; r=0,73; p=0,002). Water column Chl-a and spectrally inferred Chl-a in sediments show similar trends in concentrations with deeper water sampling, however, water column Chl-a displayed significant differences in values between various depths (p=0,0004). Consequently, climate change will much likely increase the productivity of boreal aquatic ecosystems within years and the amount of sedimentation that occurs between years due to higher temperatures. An increased amount of precipitation will also enhance the primary productivity and the transportation of allochthonous- and minerogenic material to the lake.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:umu-184160 |
| Date | January 2021 |
| Creators | Eriksson, Albin |
| Publisher | Umeå universitet, Institutionen för ekologi, miljö och geovetenskap |
| Source Sets | DiVA Archive at Upsalla University |
| Language | Swedish |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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