Institute of Ecology and Earth science

Ravila, Estonia

Institute of Ecology and Earth science

Ravila, Estonia
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Niinemets U.,Estonian University of Life Sciences | Niinemets U.,Estonian Academy of Sciences | Kahru A.,Estonian Academy of Sciences | Kahru A.,Estonian National Institute of Chemical Physics and Biophysics | And 7 more authors.
Regional Environmental Change | Year: 2017

Globally increasing temperature and modifications in precipitation patterns induce major environmental alterations in aquatic ecosystems. Particularly profound changes are predicted for arctic to temperate shallow lakes where modifications in temperature affect the distribution of ice and ice-free periods, thereby altering the timing of peak productivity, while changes in precipitation strongly alter water table depth with concomitant modifications in light distribution, temperature, and water chemistry, collectively altering the balance between primary production, organic matter consumption, and decomposition. Due to direct effects of temperature on primary productivity and microbial decomposition, raising temperatures alter the capacity of aquatic ecosystems for carbon sequestration and greenhouse gas release, and this affects atmospheric greenhouse gas concentrations and temperature, implying a feedback loop between environmental effects on ecosystems and climate change. Moreover, elevated temperature can modify the bioavailability of pollutants deposited in the past, and increase the probability for their uptake by aquatic organisms. The latter processes in turn reduce primary productivity and alter microbial decomposition, creating thus another key feedback loop between productivity, climate change, and environmental pollutants. However, warming can also enhance eutrophication and deposition of pollutants in organic sediments, further speeding up productivity and eutrophication, with the overall net effects depending on the quantitative significance of different processes. Therefore, the feedbacks arising from pollution stress must be incorporated in models intending to predict the carbon balance of aquatic ecosystems under globally changing environmental conditions. Further work on carbon balance and greenhouse gas release of aquatic ecosystems should focus on quantitative characterization of the feedback loops operative, and on how global change affects these feedback loops. © 2017 Springer-Verlag GmbH Germany


Niinemets U.,Estonian University of Life Sciences | Niinemets U.,Estonian Academy of Sciences | Kahru A.,Estonian Academy of Sciences | Kahru A.,Estonian National Institute of Chemical Physics and Biophysics | And 7 more authors.
Regional Environmental Change | Year: 2017

Unfavorable environmental conditions—abiotic stress—constitute one of the key drivers of evolution leading to environmental adaptation. Since the start of industrial revolution, natural populations are also facing a new stress—global warming—that, in turn, leads to alteration of the severity of most of the existing stress factors and emergence of novel stress combinations. Biological adaptation to environmental perturbations occurs at all levels of biological organization, but the current knowledge on the role of adaptation in responses of ecosystems to global change is limited, especially concerning the interplay of climatic and chemical/pollutant stressors. Particularly limited is the understanding of how biological adaptation alters the performance of aquatic ecosystems that integrate the pollution and nutrient loads from large catchment areas. This review describes the responses, tolerance, acclimation, and adaptation of species at different levels of aquatic food chain to globally changing environmental drivers with emphasis on arctic to temperate ecosystems. The analysis highlights major variations in tolerance and in extent and speed of acclimation and adaptation to various environmental drivers within and among species and among species groups at different trophic levels. The variety of responses to novel stressors causes modifications in species composition and diversity and can lead to asynchronous peak activities of organisms at different trophic levels. All these effects are expected to profoundly alter the aquatic ecosystem productivity, resilience, and adaptation capacity and can ultimately modify the global feedbacks between ecosystem-level processes and environmental drivers. We argue that joint efforts of researchers working at different levels of biological organization are needed to understand and predict global change effects on various functional types of organisms and scale up from physiological responses to large-scale integrated ecosystem responses in future climates. © 2017 Springer-Verlag GmbH Germany


Horak P.,Institute of Ecology and Earth science | Sild E.,Institute of Ecology and Earth science | Sepp T.,Institute of Ecology and Earth science
Journal of Experimental Biology | Year: 2010

Carotenoid and melanin pigments in the plumage of birds are hypothesized to be sensitive to oxidative stress. We manipulated oxidative status of captive greenfinches (Carduelis chloris L.) by the administration of buthionine sulfoximine (BSO), a selective inhibitor of the synthesis of glutathione (GSH), an intracellular antioxidant. Half of the birds in the treated group, as well as in the control group, also received dietary carotenoid (lutein) supplementation. BSO treatment reduced erythrocyte GSH levels and caused oxidative damage as indicated by the increased concentration of plasma malondialdehyde (MDA), an end product of lipid peroxidation. BSO treatment also reduced the brightness (i.e. increased blackness) of the tips of tail feathers grown during the experiment. These results show that a low systemic GSH level is required for development of eumelanin plumage coloration and that such a low GSH level is also potentially dangerous for the organism. Carotenoid supplementation increased plasma carotenoid levels and chroma of the yellow parts of the feathers grown during the experiment. However, carotenoid supplementation did not reduce plasma MDA levels. Manipulation of GSH did not affect plasma carotenoids or carotenoid-based plumage coloration. These findings argue against the antioxidant function of lutein in vivo and carotenoid signaling of antioxidant status. © 2010. Published by The Company of Biologists Ltd.


Ehrlich U.,Tallinn University of Technology | Reimann M.,Tallinn University | Reimann M.,Institute of Ecology and Earth science
International Conference on Energy, Environment, Devices, Systems, Communications, Computers, EEDSCC'11 | Year: 2011

The article discusses the resource utilisation conflict at the example of Jagala Waterfall, which is the highest and greatest natural waterfall in Estonia. There are plans to build a hydro-power plant there, which would conduct most of the water past the waterfall to the power plant's turbines, reducing significantly the nature values of the waterfall. The authors carried out a contingent valuation (CV) study to identify the monetary equivalent of non-market values related with Jagala waterfall in the natural state.


Preusser F.,University of Stockholm | Muru M.,Institute of Ecology and Earth science | Rosentau A.,Institute of Ecology and Earth science
Geochronometria | Year: 2014

Different post-IR Infrared Stimulated Luminescence (IRSL) approaches are applied to sediments from a Holocene coastal foredune sequence on Ruhnu Island in the eastern Baltic Sea. The comparison of De-values and ages determined by the different approaches is complimented by fading and bleaching experiments. The fading experiments imply strong fading of IRSL (50°C) signals and no fading of any of the post-IR IRSL signals, but this is not confirmed by the determined De-values. In fact, post-IR IRSL (150°C) De-values agree within errors with those calculated for IRSL (50°C). From the bleaching experiments it is inferred that the higher values observed for post-IR IRSL at more elevated stimulation temperatures (225°C/290°C) are likely related to either thermal transfer and/or slow-to-bleach components within the signal. For the dating of the Holocene foredune sequence of Ruhnu Island, the post-IR IRSL (150°C) approach is preferred and these agree with the limited independent age control available from radiocarbon dating. Accordingly, the sequence formed between ca. 7.0 ka and 2.5 ka ago. © 2013, Versita Warsaw and Springer-Verlag Wien.

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