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In Northern Finland, the most significant land use challenges are related to bioenergy production from peat extraction and forest biomass. Increasing societal demand for bioenergy may increase production rates. However, environmental impacts of peat extraction are of increasing concern, which has led to a decline in production, thereby freeing up these areas for other uses. Using storylines for different societal futures and process-based models (PERSiST and INCA), we simulated the effect of simultaneous land use change and climate change on water quality (phosphorus, nitrogen and suspended sediments concentration). Conversion of peat extraction areas to arable land, together with climate change, may pose a risk for deterioration of ecological status. On the other hand, continuous forestry may have positive impacts on water quality. Suspended sediment concentrations in the river do not exceed water quality requirements for salmonids, but nitrogen concentrations may exceed threshold values especially during high flows. A storyline emphasizing sustainable development in energy production led to the best outcome in terms of water protection.

This paper synthesizes a five-year project (BIOWATER) that assessed the effects of a developing bioeconomy on Nordic freshwaters. We used a catchment perspective and combined several approaches: comparative analyses of long-term data sets from well-monitored catchments (agricultural, with forestry, and near pristine) across Fennoscandia, catchment biogeochemical modelling and ecosystem services assessment for integration. Various mitigation measures were also studied. Benchmark Shared Socio-economic Pathways were downscaled and articulated in dialogue with national stakeholder representatives leading to five Nordic Bioeconomy Pathways (NBPs) describing plausible but different trajectories of societal development towards 2050.These were then used for catchment modelling and ecosystem service assessment. Key findings from the work synthesized here are: (a) The monitoring results from 69 catchments demonstrate that agricultural lands exported an order of magnitude more nutrients than natural catchments (medians 44 vs 4 kg P km−2 y-1 and 1450 vs 139 kg N km−2 y-1) whilst forests were intermediate (7 kg P km−2 y-1 and 200 kg N km−2 y-1). (b) Our contrasting scenarios led to substantial differences in land use patterns, which affected river flow as well as nutrient loads in two of the four modelled catchments (Danish Odense Å and Norwegian Skuterud), but not in two others (Swedish catchment C6 and Finnish Simojoki). (c) Strongly contrasting scenarios (NBP1 maximizing resource circularity versus NBP5 maximizing short-term profit) were found to lead to similar monetary estimates of total societal benefits, though for different underlying reasons – a pattern similar across the six studied Nordic catchments. (d) The ecological status of small to medium sized rivers in agricultural landscapes benefitted greatly from an increase in riparian forest cover from 10 % to 60 %. Riparian buffer strips, constructed wetlands, rewetting of ditched peatlands, and similar nature-b

Future development of bioeconomy is expected to change land use in the Nordic countries in agriculture and forestry. The changes are likely to affect water quality due to changes in nutrient run-off. To explore possible future land-use changes and their environmental impact, stakeholders and experts from four Nordic countries (Denmark, Finland, Norway and Sweden) were consulted. The methodological framework for the consultation was to identify a set of relevant land-use attributes for agriculture and forestry, e.g. tillage conservation effort, fertiliser use, animal husbandry, biogas production from manure, forestry management options, and implementation of mitigation measures, including protection of sensitive areas. The stakeholders and experts provided their opinions on how these attributes might change in terms of their environmental impacts on water quality given five Nordic bioeconomic scenarios (sustainability, business as usual, self-sufficiency, cities first and maximizing economic growth). A compilation methodology was developed to allow comparing and merging the stakeholder and expert opinions for each attribute and scenario. The compiled opinions for agriculture and forestry suggest that the business-as-usual scenario may slightly decrease the current environmental impact for most attributes due to new technologies, but that the sustainability scenario would be the only option to achieve a clear environmental improvement. In contrast, for the self-sufficiency scenario, as well as the maximum growth scenario, a deterioration of the environment and water quality was expected for most of the attributes. The results from the stakeholder consultations are used as inputs to models for estimating the impact of the land-use attributes and scenarios on nutrient run-off from catchments in the Nordic countries (as reported in other papers in this special issue). Furthermore, these results will facilitate policy level discussions concerning how to facilitat

Iron (Fe) is an important element in aquatic ecosystems worldwide because it is intimately tied with multiple abiotic and biotic phenomena. Here, we give a survey of manifold influences of Fe, and the key factors affecting it in the boreal catchments and their waters. It includes the perspectives of biogeochemistry, hydrology, ecology, and river basin management. We emphasize views on the dynamics and impacts of different forms of Fe in riverine environments, including organic colloids and particles, as well as inorganic fractions. We also provide perspectives for land use management in boreal catchments and suggest guidelines for decision making and water management. Based on our survey, the main emphases of water protection and management programs should be (i) prevention of Fe mobilization from soil layers by avoiding unnecessary land-use activities and minimizing soil disturbance in high-risk areas; (ii) disconnecting Fe-rich ground water discharge from directly reaching watercourses; and (iii) decreasing transport of Fe to watercourses by applying efficient water pollution control approaches. These approaches may require specific methods that should be given attention depending on catchment conditions in different areas. Finally, we highlight issues requiring additional research on boreal catchments. A key issue is to increase our understanding of the role of Fe in the utilization of DOM in riverine food webs, which are typically highly heterotrophic. More knowledge is needed on the metabolic and behavioral resistance mechanisms that aquatic organisms, such as algae, invertebrates, and fish, have developed to counter the harmful impacts of Fe in rivers with naturally high Fe and DOM concentrations. It is also emphasized that to fulfil the needs presented above, as well as to develop effective methods for decreasing the harmful impacts of Fe in water management, the biogeochemical processes contributing to Fe transport from catchments via rivers to estu

Purpose: Adsorbent amendment to contaminated sediments is one in situ remediation method to decrease the bioaccessibility of pollutants from the sediments. In this work, alkali-activated blast furnace slag (BFS) granules were used in a field experiment at Lake Kivijärvi (Finland). The lake was heavily affected by a mining accident in 2012, which released a significant peak load of metals and sulfate. The purpose of this work was to evaluate the performance of the novel amendment material for in situ remediation in real conditions with a preliminary cost estimation. Methods: Alkali-activated BFS granules were prepared and characterized for composition, microstructure, and surface properties. Two mesocosms were placed in the lake: one with granule dosing and another without. Sediment and pore water samples were collected after a two-week period. Similar small-scale experiment was performed in laboratory with a three-month duration. Bioaccessibility of metals from sediments was assessed with a three-stage leaching procedure. Results: The granules were effective in decreasing the mobility of Fe, Zn, Ni, and Cr in all leaching stages by approximately 50–90% in comparison with unamended sediment in the mesocosm experiment. Laboratory-scale incubation experiments also indicated decreased release of Ba, Co, Ni, Al, Fe, Mg, Mn and S. The estimated material costs were lower than the removal of the contaminated sediments with dredging and off-site treatment. Conclusion: The results showed preliminarily the effectiveness of alkaline-activated BFS in the remediation of metal-contaminated sediments in a field experiment. However, topics requiring further study are the leaching of trace elements from the material and impact on the sediment pH.

Nordic water bodies face multiple stressors due to human activities, generating diffuse loading and climate change. The ‘green shift’ towards a bio-based economy poses new demands and increased pressure on the environment. Bioeconomy-related pressures consist primarily of more intensive land management to maximise production of biomass. These activities can add considerable nutrient and sediment loads to receiving waters, posing a threat to ecosystem services and good ecological status of surface waters. The potential threats of climate change and the ‘green shift’ highlight the need for improved understanding of catchment-scale water and element fluxes. Here, we assess possible bioeconomy-induced pressures on Nordic catchments and associated impacts on water quality. We suggest measures to protect water quality under the ‘green shift’ and propose ‘road maps’ towards sustainable catchment management. We also identify knowledge gaps and highlight the importance of long-term monitoring data and good models to evaluate changes in water quality, improve understanding of bioeconomy-related impacts, support mitigation measures and maintain ecosystem services.

Ammonia emissions vary greatly at a local scale, and effects (eutrophication, acidification) occur primarily close to sources. Therefore it is important that spatially distributed emission estimates are located as accurately as possible. The main source of ammonia emissions is agriculture, and therefore agricultural survey statistics are the most important input data to an ammonia emission inventory alongside per activity estimates of emission potential. In the UK, agricultural statistics are collected at farm level, but are aggregated to parish level, NUTS-3 level or regular grid resolution for distribution to users. In this study, the Modifiable Areal Unit Problem (MAUP), associated with such amalgamation, is investigated in the context of assessing the spatial distribution of ammonia sources for emission inventories. England was used as a test area to study the effects of the MAUP. Agricultural survey data at farm level (point data) were obtained under license and amalgamated to different areal units or zones: regular 1-km, 5-km, 10-km grids and parish level, before they were imported into the emission model. The results of using the survey data at different levels of amalgamation were assessed to estimate the effects of the MAUP on the spatial inventory. The analysis showed that the size and shape of aggregation zones applied to the farm-level agricultural statistics strongly affect the location of the emissions estimated by the model. If the zones are too small, this may result in false emission “hot spots”, i.e., artificially high emission values that are in reality not confined to the zone to which they are allocated. Conversely, if the zones are too large, detail may be lost and emissions smoothed out, which may give a false impression of the spatial patterns and magnitude of emissions in those zones. The results of the study indicate that the MAUP has a significant effect on the location and local magnitude of emissions in spatial inventories where amalgama

Nutrient export from drained peatland has significant impacts on aquatic environments in Nordic catchments. Spatial information on variations in nutrient concentrations across different landscapes and land uses is needed to design measures for achieving the good ecological status of the EU Water Framework Directive. In this study we determined background concentrations in natural peatland-dominated streams and examined effects of peatland use practices on water quality in headwater catchments. We quantified sources for different elements by joint analysis of water chemistry, isotopes, and hydrology for 62 small catchments in North Ostrobothnia, Finland. Concentrations of nutrients and suspended solids were relatively high in catchments containing drained peatland. In particular, dissolved nitrogen and phosphorus concentrations were elevated during baseflow conditions when flow likely originated from deeper soil layers. Total concentrations of nutrients, suspended solids, and loss on ignition also showed elevated values, and changes in the ratio of dissolved and particulate forms, especially the C/N ratio, were observed. Past drainage had a stronger effect on organic matter and nutrients concentrations than local hydroclimate conditions. These results strongly indicate that current water protection methods are not sufficient to capture all seasonal variations in nutrient and suspended solid loads from drained peatland. Thus, more effort and actions are needed for water protection in such areas.

Species distributions are structured by regional and local determinants, which operate at multiple spatial and temporal scales. The purpose of our work was to distinguish the relative roles of local variables, climate, geographical location and post glaciation condition (i.e., delineation between supra- and subaquatic lakes during the post-glacial Ancylus Lake) in explaining variation in macrophyte community composition of all taxa, helophytes and hydrophytes. In addition, we investigated how these four explanatory variable groups affected macrophyte strategy groups based on Grime’s classification. Using partial linear regression and variation partitioning, we found that macrophyte communities are primarily filtered by local determinants together with regional characteristics at the studied spatial scale. We further evidenced that post glaciation condition indirectly influenced on local water quality variables, which in turn directly contributed to the macrophyte communities. We thus suggest that regional determinants interact with local-scale abiotic factors in explaining macrophyte community patterns and examining only regional or local factors is not sufficient for understanding how aquatic macrophyte communities are structured locally and regionally.

Aim: We studied global variation in beta diversity patterns of lake macrophytes using regional data from across the world. Specifically, we examined (1) how beta diversity of aquatic macrophytes is partitioned between species turnover and nestedness within each study region, and (2) which environmental characteristics structure variation in these beta diversity components. Location: Global. Methods: We used presence–absence data for aquatic macrophytes from 21 regions distributed around the world. We calculated pairwise‐site and multiple‐site beta diversity among lakes within each region using Sørensen dissimilarity index and partitioned it into turnover and nestedness coefficients. Beta regression was used to correlate the diversity coefficients with regional environmental characteristics. Results: Aquatic macrophytes showed different levels of beta diversity within each of the 21 study regions, with species turnover typically accounting for the majority of beta diversity, especially in high‐diversity regions. However, nestedness contributed 30–50% of total variation in macrophyte beta diversity in low‐diversity regions. The most important environmental factor explaining the three beta diversity coefficients (total, species turnover and nestedness) was elevation range, followed by relative areal extent of freshwater, latitude and water alkalinity range. Main conclusions: Our findings show that global patterns in beta diversity of lake macrophytes are caused by species turnover rather than by nestedness. These patterns in beta diversity were driven by natural environmental heterogeneity, notably variability in elevation range (also related to temperature variation) among regions. In addition, a greater range in alkalinity within a region, likely amplified by human activities, was also correlated with increased macrophyte beta diversity. These findings suggest that efforts to conserve aquatic macrophyte diversity should primarily focus on regions with large