DOI: 10.1016/j.quascirev.2013.11.020
Scopus记录号: 2-s2.0-84890285958
论文题名: Spectral absorbance of benthic cladoceran carapaces as a new method for inferring past UV exposure of aquatic biota
作者: Nevalainen L. ; Rautio M.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2014
卷: 84 起始页码: 109
结束页码: 115
语种: 英语
英文关键词: Alpine lakes
; Boreal lakes
; Cladocera
; Fossil pigments
; Lake sediments
; Melanin
; Paleolimnology
; UV radiation
Scopus关键词: Alpine lakes
; Boreal lakes
; Cladocera
; Fossil pigments
; Lake sediments
; Biological materials preservation
; Catchments
; Melanin
; Paleolimnology
; Sedimentation
; Ultraviolet radiation
; Lakes
; absorption
; alpine environment
; aquatic community
; benthic environment
; boreal forest
; carbon
; catchment
; cost-benefit analysis
; crustacean
; divergence
; fossil record
; lacustrine deposit
; Little Ice Age
; paleolimnology
; permafrost
; pigment
; pollution exposure
; primary production
; radioactive pollution
; spectral analysis
; ultraviolet radiation
; Alps
; Austria
英文摘要: We developed a method for measuring fossil cladoceran (Branchiopoda) carapace absorbance to infer past ultraviolet radiation (UV) exposure in lakes. This was done under the presumptions that cladocerans synthesize photoprotective compounds, of which melanin is the main UV-absorbing pigment, to their exoskeletons and melanin is preserved in sedimentary cladoceran remains. We extracted large-sized cladoceran (benthic Alona spp.) carapaces from subsections of sediment cores from two environmentally divergent lakes; a humic boreal forest lake in eastern Finland (past 1500 years) and a clear-water mountain lake in the Austrian Alps (past 300 years). We measured the absorbance of extracted carapaces with a spectrophotometer under visible light and UV wavelengths using an adapter, which was designed to hold the microfossils. When compared to the spectrum of synthetic melanin, the shapes of absorbance spectra at the 700-280nm range suggested that the fossil carapaces contained melanin. The carapace absorbance under UV throughout the sediment cores was significantly higher in the clear-water alpine lake than in the humic boreal lake reflecting differences in the general underwater UV and optical environments between the sites. In addition, carapace absorbance was significantly higher during the Little Ice Age (LIA) than during pre- or post-LIA periods in both lakes. In the alpine lake, this was most likely a response to increased underwater UV induced by reduced primary production and more transparent water column during the cold summers of LIA, whereas reduced input of carbon compounds from the catchment through elongated permafrost and ice-cover periods likely induced higher water transparency in the boreal lake during this cold climate phase. We conclude that fossil melanin provides a good estimation of past underwater UV exposure in lakes with large cladoceran carapaces preserved in sediments and that the method introduced here is easy and cost- and time-efficient technique to be widely used in paleoaquatic UV inferences. © 2013 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/60406
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Environmental Sciences, University of Helsinki, Niemenkatu 73, 15140 Lahti, Finland; Department of Geosciences and Geography, 00014 University of Helsinki, P.O. Box 64 (Gustaf Hällströmin katu 2a), Finland; Département des Sciences Fondamentales and Centre for Northern Studies (CEN), Université du Québec á Chicoutimi, 555, boulevard de l'Université Chicoutimi, Québec G7H 2B1, Canada
Recommended Citation:
Nevalainen L.,Rautio M.. Spectral absorbance of benthic cladoceran carapaces as a new method for inferring past UV exposure of aquatic biota[J]. Quaternary Science Reviews,2014-01-01,84