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| 2. |
- de Wit, Heleen A., et al.
(författare)
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Current Browning of Surface Waters Will Be Further Promoted by Wetter Climate
- 2016
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Ingår i: ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS. - : American Chemical Society (ACS). - 2328-8930. ; 3:12, s. 430-435
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Tidskriftsartikel (refereegranskat)abstract
- Browning of surface waters because of increasing terrestrial dissolved organic carbon (OC) concentrations is a concern for drinking water providers and can impact land carbon storage. We show that positive trends in OC in 474 streams, lakes, and rivers in boreal and subarctic ecosystems in Norway, Sweden, and Finland between 1990 and 2013 are surprisingly constant across climatic gradients and catchment sizes (median, +1.4% year(-1); interquartile range, +0.8-2.0% year(-1)), implying that water bodies across the entire landscape are browning. The largest trends (median, +1.7% year(-1)) were found in regions impacted by strong reductions in sulfur deposition, while subarctic regions showed the least browning (median, +0.8% year(-1)). In dry regions, precipitation was a strong and positive driver of OC concentrations, declining in strength moving toward high rainfall sites. We estimate that a 10% increase in precipitation will increase mobilization of OC from soils to freshwaters by at least 30%, demonstrating the importance of climate wetting for the carbon cycle. We conclude that upon future increases in precipitation, current browning trends will continue across the entire aquatic continuum, requiring expensive adaptations in drinking water plants, increasing land to sea export of carbon, and impacting aquatic productivity and greenhouse gas emissions.
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| 3. |
- Futter, Martyn, et al.
(författare)
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Conceptualizing and communicating management effects on forest water quality
- 2016
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 45, s. S188-S202
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Tidskriftsartikel (refereegranskat)abstract
- We present a framework for evaluating and communicating effects of human activity on water quality in managed forests. The framework is based on the following processes: atmospheric deposition, weathering, accumulation, recirculation and flux. Impairments to water quality are characterized in terms of their extent, longevity and frequency. Impacts are communicated using a "traffic lights" metaphor for characterizing severity of water quality impairments arising from forestry and other anthropogenic pressures. The most serious impairments to water quality in managed boreal forests include (i) forestry activities causing excessive sediment mobilization and extirpation of aquatic species and (ii) other anthropogenic pressures caused by long-range transport of mercury and acidifying pollutants. The framework and tool presented here can help evaluate, summarize and communicate the most important issues in circumstances where land management and other anthropogenic pressures combine to impair water quality and may also assist in implementing the "polluter pays" principle.
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| 4. |
- Futter, Martyn, et al.
(författare)
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Forests, Forestry and the Water Framework Directive in Sweden : A Trans-Disciplinary Commentary
- 2011
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Ingår i: Forests. - : MDPI AG. - 1999-4907. ; 2:1, s. 261-282
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Tidskriftsartikel (refereegranskat)abstract
- The Water Framework Directive (WFD) is an ambitious piece of legislation designed to protect and improve water quality throughout Europe. However, forests are only mentioned once in the WFD, and forestry is not mentioned at all, despite its potential implications for streams, rivers and lakes. Here we present a transdisciplinary commentary on the WFD and its implications for forests and forestry in Sweden. This commentary has been prepared by forestry stakeholders, biophysical and social scientists. While we were cognizant of a large body of discipline-specific research, there are very few inter-or trans-disciplinary commentaries which link academic and stakeholder perspectives on the WFD. We had originally felt that there would be little commonality in our concerns. However, we found significant areas of agreement. Our key areas of concern about the implications of the WFD for forestry in Sweden included: (i) concerns about what is meant by good ecological status and how it is assessed; (ii) a perceived lack of clarity in the legal framework; (iii) an inadequate environmental impact assessment process; and (iv) uncertainties about appropriate programs of measures for improving water quality. We were also concerned that ecosystem services provided by forests and the positive effects of forestry on water quality are inadequately recognized in the WFD.
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| 5. |
- Futter, Martyn, et al.
(författare)
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Uncertainty in silicate mineral weathering rate estimates : source partitioning and policy implications
- 2012
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 7:2, s. 024025-
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Tidskriftsartikel (refereegranskat)abstract
- Precise and accurate estimates of silicate mineral weathering rates are crucial when setting policy targets for long-term forest sustainability, critical load calculations and assessing consequences of proposed geo-engineering solutions to climate change. In this paper, we scrutinize 394 individual silicate mineral weathering estimates from 82 sites on three continents. We show that within-site differences of several hundred per cent arise when different methods are used to estimate weathering rates, mainly as a result of uncertainties related to input data rather than conceptually different views of the weathering process. While different methods tend to rank sites congruently from high to low weathering rates, large within-site differences in estimated weathering rate suggest that policies relying on quantitative estimates based upon a single method may have undesirable outcomes. We recommend the use of at least three independent estimates when making management decisions related to silicate mineral weathering rates.
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| 6. |
- Josefsson, Sarah, et al.
(författare)
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Persistent Organic Pollutants in Streamwater : Influence of Hydrological Conditions and Landscape Type
- 2016
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 50:14, s. 7416-7424
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Tidskriftsartikel (refereegranskat)abstract
- Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and hexachlorobenzene (HCB) in streamwater were measured in a remote catchment in northern Sweden and downstream to the Baltic Sea. Sampling took place at seven sites during two years and under different hydrological conditions: during the snow-free, snow-covered, and spring-flood seasons. Concentrations varied substantially between seasons and were up to 20 times higher during the spring flood compared to the preceding snow-covered period. The increase in concentrations with runoff was due to higher levels of particle-associated contaminants, while the dissolved concentrations remained stable. Particulate-contaminant concentrations were positively correlated primarily to suspended particulate matter (SPM) at sites in areas with a high land-cover fraction of sorted sediment. When upstream sampling locations were compared, a mire-dominated stream had higher concentrations and a lower retention of atmospherically deposited contaminants than a forest stream of the same catchment size. Contaminant concentrations (normalized to volume) did not increase consistently downstream despite the presence of several point sources. However, when normalized to the amount of SPM, concentrations were on average >20 times higher at the outlet in the Baltic Sea compared to the outlet from the remote catchment without point sources.
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| 7. |
- Kasurinen, Ville, et al.
(författare)
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Modeling nonlinear responses of DOC transport in boreal catchments in Sweden
- 2016
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Ingår i: Water resources research. - 0043-1397 .- 1944-7973. ; 52:7, s. 4970-4989
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Tidskriftsartikel (refereegranskat)abstract
- Stream water dissolved organic carbon (DOC) concentrations display high spatial and temporal variation in boreal catchments. Understanding and predicting these patterns is a challenge with great implications for water quality projections and carbon balance estimates. Although several biogeochemical models have been used to estimate stream water DOC dynamics, model biases common during both rain and snow melt-driven events. The parsimonious DOC-model, K-DOC, with 10 calibrated parameters, uses a nonlinear discharge and catchment water storage relationship including soil temperature dependencies of DOC release and consumption. K-DOC was used to estimate the stream water DOC concentrations over 5 years for eighteen nested boreal catchments having total area of 68 km2 (varying from 0.04 to 67.9 km2). The model successfully simulated DOC concentrations during base flow conditions, as well as, hydrological events in catchments dominated by organic and mineral soils reaching NSEs from 0.46 to 0.76. Our semimechanistic model was parsimonious enough to have all parameters estimated using statistical methods. We did not find any clear differences between forest and mire-dominated catchments that could be explained by soil type or tree species composition. However, parameters controlling slow release and consumption of DOC from soil water behaved differently for small headwater catchments (less than 2 km2) than for those that integrate larger areas of different ecosystem types (10–68 km2). Our results emphasize that it is important to account for nonlinear dependencies of both, soil temperature, and catchment water storage, when simulating DOC dynamics of boreal catchments.
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| 8. |
- Klaminder, Jonatan, 1976-, et al.
(författare)
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Silicate mineral weathering rate estimates : Are they precise enough to be useful when predicting the recovery of nutrient pools after harvesting?
- 2011
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 261:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Are current estimates of silicate minerals weathering rates precise enough to predict whether nutrient pools will recover after forest harvesting? Answering this question seems crucial for sustainable forestry practices on silicate dominated soils. In this paper, we synthesize estimated Ca and K weathering rates (derived using seven different approaches) from a forested area in northern Sweden (the Svartberget-Krycklan catchment) to evaluate the precision of weathering rate estimates. The methods were: mass-balance budgets (catchment and pedon-scale); long-term weathering losses inferred from weathered soil profiles (using zirconium as a conservative tracer); strontium isotopes ((86)Sr/(85)Sr) as proxy for catchment export of geogenic Ca; climate based regressions; a steady-state, process-based weathering model (PROFILE) and a dynamic, conceptual catchment geochemistry model (MAGIC). The different methods predict average weathering rates of 0.67 +/- 0.71 g Ca m(-2) year(-1) (mean +/- stdev) and 0.39 +/- 0.38 g K m(-2) year(-1), suggesting a cumulative weathering release during a forest rotation period of 100 years that is the same magnitude as losses induced by forest harvesting at the end of the period. Clearly, forestry practices have the capacity to significantly alter the long-term nutrient status of the soil and cation concentrations in soil-water runoff. However, the precision in weathering estimates are lower than that needed to distinguish between effects on nutrient pools by different forest practices (complete-tree harvesting versus conventional stem only harvest). Therefore, we argue that nutrient budgets, where weathering rates play a crucial role, cannot be used as basis for resolving whether different harvesting techniques will allow nutrient pools to recover within one rotation period. Clearly, this hampers the prerequisite for sound decision making regarding forestry practices on silicate mineral dominated soils. (C) 2010 Elsevier B.V. All rights reserved.
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| 9. |
- Kothawala, Dolly N., et al.
(författare)
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The relative influence of land cover, hydrology, and in-stream processing on the composition of dissolved organic matter in boreal streams
- 2015
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Ingår i: Journal of Geophysical Research - Biogeosciences. - 2169-8953 .- 2169-8961. ; 120:8, s. 1491-1505
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Tidskriftsartikel (refereegranskat)abstract
- Low-order boreal streams are particularly sensitive interfaces where dissolved organic matter (DOM) is transported from soils to inland waters. Disentangling the relative influence of key environmental factors suspected to influence stream water DOM composition is highly relevant to predicting the reactivity and fate of terrestrial DOM entering inland waters. Here we examined changes to DOM composition using absorbance and fluorescence, from 17 boreal streams ranging from first to fourth orders, over 14 months, including the rarely studied winter season, and two snowmelt periods (n = 836). We also analyzed soil pore water samples from three forest soil lysimeters to a depth of 70 cm (n = 60). Of five identified fluorescing parallel factor analysis components, two (C4 and C5) expressed a clear mire wetland or forest signature, providing distinct molecular markers of dominant land cover. In fact, land cover alone explained 49% of the variability in DOM composition. In contrast, seasonal fluctuations in hydrology only contributed to minor shifts (8%) in the composition of stream water DOM, while in-stream transformations to DOM composition were undetectable. These findings suggest that low-order boreal streams act as a passive pipe, since in-stream processing of DOM is restricted by short water residence times (6 h to 2 days). In addition, we demonstrated the sensitivity of optical approaches to distinguish between key terrestrial sources of DOM in the boreal landscape. By distinguishing the proportional leverage of key environmental controls on headwater stream DOM composition, we are better equipped to predict where and when key DOM transformations occur in the aquatic conduit.
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| 10. |
- Laudon, Hjalmar, et al.
(författare)
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Consequences of More Intensive Forestry for the Sustainable Management of Forest Soils and Waters
- 2011
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Ingår i: Forests. - : MDPI AG. - 1999-4907. ; 2, s. 243-260
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Tidskriftsartikel (refereegranskat)abstract
- Additions of nutrients, faster growing tree varieties, more intense harvest practices, and a changing climate all have the potential to increase forest production in Sweden, thereby mitigating climate change through carbon sequestration and fossil fuel substitution. However, the effects of management strategies for increased biomass production on soil resources and water quality at landscape scales are inadequately understood. Key knowledge gaps also remain regarding the sustainability of shorter rotation periods and more intensive biomass harvests. This includes effects of fertilization on the long-term weathering and supply of base cations and the consequences of changing mineral availability for future forest production. Furthermore, because soils and surface waters are closely connected, management efforts in the terrestrial landscape will potentially have consequences for water quality and the ecology of streams, rivers, and lakes. Here, we review and discuss some of the most pertinent questions related to how increased forest biomass production in Sweden could affect soils and surface waters, and how contemporary forestry goals can be met while minimizing the loss of other ecosystem services. We suggest that the development of management plans to promote the sustainable use of soil resources and water quality, while maximizing biomass production, will require a holistic ecosystem approach that is placed within a broader landscape perspective.
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