| 1. |
- Björnerås, Caroline, et al.
(författare)
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Inland blue holes of The Bahamas - chemistry and biology in a unique aquatic environment
- 2020
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Ingår i: Fundamental and Applied Limnology. - : Schweizerbart science publishers. - 1863-9135. ; 194:2, s. 95-106
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Tidskriftsartikel (refereegranskat)abstract
- While lake systems in temperate regions have been extensively studied, tropical and subtropical systems have received less attention. Here, we describe the water chemistry and biota of ten inland blue holes on Andros Island, The Bahamas, representative of the morphological, abiotic, and biotic variation among Androsian inland blue holes. The majority of the studied blue holes were vertically stratified with oxic freshwater overlying anoxic saline groundwater of marine origin. Water chemistry (e.g. total phosphorus and nitrogen) in shallow waters was similar among blue holes, while turbidity and water color varied. Presence of hydrogen sulfide and reduced iron in and below the halocline indicate reducing conditions in all stratified blue holes. The biota above the halocline was also similar among blue holes with a few taxa dominating the phytoplankton community, and the zooplankton community consisting of copepods and rotifers. The Bahamas mosquitofish (Gambusia hubbsi) was present in all investigated blue holes, often accompanied by other small planktivorous fish, while the piscivorous bigmouth sleeper (Gobiomorus donnitor) was only present in some of the blue holes. Our field study reinforces that inland blue holes are highly interesting for biogeochemical research, and provide naturally replicated systems for evolutionary studies.
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| 2. |
- Kritzberg, Emma S., et al.
(författare)
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Browning of freshwaters : Consequences to ecosystem services, underlying drivers, and potential mitigation measures
- 2020
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Ingår i: Ambio: a Journal of the Human Environment. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 49:2, s. 375-390
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Forskningsöversikt (refereegranskat)abstract
- Browning of surface waters, as a result of increasing dissolved organic carbon and iron concentrations, is a widespread phenomenon with implications to the structure and function of aquatic ecosystems. In this article, we provide an overview of the consequences of browning in relation to ecosystem services, outline what the underlying drivers and mechanisms of browning are, and specifically focus on exploring potential mitigation measures to locally counteract browning. These topical concepts are discussed with a focus on Scandinavia, but are of relevance also to other regions. Browning is of environmental concern as it leads to, e.g., increasing costs and risks for drinking water production, and reduced fish production in lakes by limiting light penetration. While climate change, recovery from acidification, and land-use change are all likely factors contributing to the observed browning, managing the land use in the hydrologically connected parts of the landscape may be the most feasible way to counteract browning of natural waters.
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| 3. |
- Škerlep, Martin, et al.
(författare)
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Afforestation driving long-term surface water browning
- 2020
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 26:3, s. 1390-1399
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Tidskriftsartikel (refereegranskat)abstract
- Increase in surface water color (browning), caused by rising dissolved organic carbon (DOC) and iron concentrations, has been widely reported and studied in the last couple of decades. This phenomenon has implications to aquatic ecosystem function and biogeochemical carbon cycling. While recovery from acidification and changes in climate-related variables, such as precipitation and length of growing season, are recognized as drivers behind browning, land-use change has received less attention. In this study, we include all of the above factors and aim to discern their individual and combined contribution to water color variation in an unprecedentedly long (1940–2016) and highly resolved dataset (~20 times per month), from a river in southern Sweden. Water color showed high seasonal variability and a marked long-term increase, particularly in the latter half of the dataset (~1980). Short-term and seasonal variations were best explained by precipitation, with temperature playing a secondary role. All explanatory variables (precipitation, temperature, S deposition, and land-use change) contributed significantly and together predicted 75% of the long-term variation in water color. Long-term change was best explained by a pronounced increase in Norway spruce (Picea abies Karst) volume—a measure of land-use change and a proxy for buildup of organic soil layers—and by change in atmospheric S deposition. When modeling water color with a combination of explanatory variables, Norway spruce showed the highest contribution to explaining long-term variability. This study highlights the importance of considering land-use change as a factor behind browning and combining multiple factors when making predictions in water color and DOC.
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