| 1. |
- Agstam-Norlin, O., et al.
(författare)
-
A 25-year retrospective analysis of factors influencing success of aluminum treatment for lake restoration
- 2021
-
Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 200
-
Tidskriftsartikel (refereegranskat)abstract
- For more than 50 years, aluminum (Al)-salts have been used with varying degrees of success to inactivate excess mobile phosphorus (P) in lake sediments and restore lake water quality. Here, we analyzed the factors influencing effectiveness and longevity of Al-treatments performed in six Swedish lakes over the past 25 years. Trends in post-treatment measurements of total phosphorus (TP), Chlorophyll a (Chl_a), Secchi disk depth (SD) and internal P loading rates (Li) were analyzed and compared to pre-treatment conditions. All measured water quality parameters improved significantly during at least the first 4 years post-treatment and determination of direct effects of Al-treatment on sediment P release (Li) was possible for three lakes. Improvements in TP (-29 to -80%), Chl_a (-50 to -78%), SD (7 to 121%) and Li (-68 to -94%) were observed. Treatment longevity, determined via decreases in surface water TP after treatment, varied from 7 to >47 years. Lake type, Al dose, and relative watershed area were related to longevity. In addition, greater binding efficiency between Al and P was positively related to treatment longevity, which has not previously been shown. Our findings also demonstrate that adequate, long-term monitoring programs, including proper determination of external loads, are crucial to document the effect of Al-treatment on sediment P release and lake water quality.
|
|
| 2. |
- Agstam, Oskar, et al.
(författare)
-
Optimization of aluminum treatment efficiency to control internal phosphorus loading in eutrophic lakes
- 2020
-
Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 185
-
Tidskriftsartikel (refereegranskat)abstract
- Historical accumulation of phosphorus (P) in lake sediment often contributes to and sustains eutrophic conditions in lakes, even when external sources of P are reduced. The most cost-effective and commonly used method to restore the balance between P and P-binding metals in the sediment is aluminum (Al) treatment. The binding efficiency of Al, however, has varied greatly among treatments conducted over the past five decades, resulting in substantial differences in the amount of P bound per unit Al. We analyzed sediment from seven previously Al treated Swedish lakes to investigate factors controlling binding efficiency. In contrast to earlier work, lake morphology was negatively correlated to binding efficiency, meaning that binding efficiency was higher in lakes with steeply sloping bathymetry than in lakes with more gradually sloping bottoms. This was likely due to Al generally being added directly into the sediment, and not to the water column. Higher binding efficiencies were detected when Al was applied directly into the sediment, whereas the lowest binding efficiency was detected where Al was instead added to the water column. Al dose, mobile sediment P and lake morphology together explained 87% of the variation in binding efficiency among lakes where Al was added directly into the sediment. This led to the development of a model able to predict the optimal Al dose to maximize binding efficiency based on mobile sediment P mass and lake morphology. The predictive model can be used to evaluate cost-effectiveness and potential outcomes when planning Al-treatment using direct sediment application to restore water quality in eutrophic lakes.
|
|
| 3. |
- Agstam, Oskar, et al.
(författare)
-
Ökad kunskap om kassodlingens miljöeffekter med fokus på fosfor
- 2023
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Öppen kassodling av regnbåge och röding i nordliga sjöar och vattenkraftsmagasin är den vanligaste formen av vattenbruk i Sverige idag. Det finns både fördelar och nackdelar med öppen kassodling. Fiskens välfärd är bättre eftersom de lever i en mer naturlig miljö, men avfallsprodukterna från denna typ av vattenbruk kan inte behandlas innan de når miljön.Allt jordbruk påverkar miljön, och vattenbruket är inte annorlunda. En av de främsta formerna av påverkan i samband med livsmedelsproduktion är läckage av näringsämnen. Nästan alla djur i jordbruk behöver utfodras och de flesta odlade växter behöver gödslas. Mycket arbete läggs på att utveckla foder och utfodringsstrategier som maximerar utfodrade djurs förmåga att ta upp och behålla näringsämnen. Men vissa näringsämnen går oundvikligen förlorade i urin, avföring och oätet foder. I dag använder alla former av jordbruk i Sverige näringsämnen på ett effektivare sätt än vad som gjordes tidigare, detta gäller även för vattenbruket. Därför är äldre studier av vattenbrukets miljöpåverkan inte längre fullständigt relevanta eftersom industrin använder näringsämnen mer effektivt än tidigare.Fosfor och kväve är de två huvudsakliga näringsämnena som släpps ut i miljön genom matproduktion. När dessa näringsämnen kommer ut i sötvatten eller i havet kan de bidra till ett problem som kallas "övergödning". Näringsämnen är gödningsmedel som främjar ökad tillväxt i vatten av exempelvis alger och andra växter. När dessa växter dör och sjunker till botten kan de orsaka ytterligare problem, inklusive förbrukning av syre i vattnet, försämring av sedimentkvaliteten och förlust av biologisk mångfald.I svenska fjällsjöar och vattenkraftsmagasin är fosfor typiskt sett det vanligaste begränsande näringsämnet. Eventuella ytterligare fosfortillsatser kan därmed bidra till ökad tillväxt i vattnet och en för stor tillförsel av näringsämnen kommer att orsaka övergödning. Att kvantifiera påverkan på vatten- och sedimentkvalitet vid öppen kassodling i sötvattensförhållanden som är typiska för norra Sverige är en pusselbit på vägen mot en ökad hållbarhet för vattenbruket.I den här rapporten, där studien är finansierad av Jordbruksverket, fokuserar vi på fosfor och dess omvandling i miljön vid fiskodling i öppna kassar. Vi svarar på tre frågor: hur mycket fosfor släpps ut vid fiskodling? Vad händer med fosforn efter att det släppts ut? Hur lång tid tar det för miljön att återhämta sig efter att en fiskodling upphört? Vi fann att drygt hälften (54 %) av fosforn som finns i ett kommersiellt foder släpps ut i miljön. Cirka 1/5 (21 %) av fosforn i fodret kommer sannolikt att bidra till en omedelbar växttillväxt, medan cirka 1/3 (33 %) kommer att deponeras i sedimentet under odlingskassarna.Internationella studier har visat att näringsämnen som frigörs vid vattenbruk i öppna kassar under vissa omständigheter kan ha positiva effekter, särskilt i näringsfattiga system. Dessa fynd kan vara relevanta för svenska vattenkraftmagasin.Att veta vad som händer med fosforn i sedimentet är nyckeln till att förstå den långsiktiga miljöpåverkan från fiskodlingar. Våra resultat antyder att cirka 2/3 (70 %) av fosforn i sediment under fiskodlingar inte kommer att läcka ut. Av de 30 % som kan läcka kommer potentiellt cirka 10 % (dvs. 3 % av totalen) släppas ut varje år. Våra resultat antyder att dagens vattenbruk i öppna kassar är mindre förorenande än det var tidigare. De lyfter också fram behovet av ytterligare arbete med foderutveckling i framtiden samt behovet av en ökad förståelse kring var de näringsämnen som frigörs vid fiskodling tar vägen.Kunskap om miljöpåverkan från fiskodling i öppna kassar i kalla, näringsfattiga system behöver göras tillgänglig och kommuniceras till svenska intressenter. Specifikt behöver vi dokumentera den nuvarande vetenskapliga förståelsen för vart det fosfor (P) som släpps ut vid fiskodling i öppna kassar tar vägen i vatten och sediment. Vi behöver också dokumentera och utvärdera andra nationella eller internationella studier som kan bidra till att förstå den nuvarande svenska situationen. Vi behöver veta mer om den långsiktiga depositionen av det fosfor som frigörs vid fiskodling, inklusive den tid det tar för återhämtning efter att fiskodlingen upphört.
|
|
| 4. |
- Baho, Didier Ludovic, et al.
(författare)
-
Assessing temporal scales and patterns in time series: Comparing methods based on redundancy analysis
- 2015
-
Ingår i: Ecological Complexity. - : Elsevier BV. - 1476-945X. ; 22, s. 162-168
-
Tidskriftsartikel (refereegranskat)abstract
- Time-series modelling techniques are powerful tools for studying temporal scaling structures and dynamics present in ecological and other complex systems and are gaining popularity for assessing resilience quantitatively. Among other methods, canonical ordinations based on redundancy analysis are increasingly used for determining temporal scaling patterns that are inherent in ecological data. However, modelling outcomes and thus inference about ecological dynamics and resilience may vary depending on the approaches used. In this study, we compare the statistical performance, logical consistency and information content of two approaches: (i) asymmetric eigenvector maps (AEM) that account for linear trends and (ii) symmetric distance-based Moran's eigenvector maps (MEM), which requires detrending of raw data to remove linear trends prior to analysis. Our comparison is done using long-term water quality data (25 years) from three Swedish lakes. This data set therefore provides the opportunity for assessing how the modelling approach used affects performance and inference in time series modelling. We found that AEM models had consistently more explanatory power than MEM, and in two out of three lakes AEM extracted one more temporal scale than MEM. The scale-specific patterns detected by AEM and MEM were uncorrelated. Also individual water quality variables explaining these patterns differed between methods, suggesting that inferences about systems dynamics are dependent on modelling approach. These findings suggest that AEM might be more suitable for assessing dynamics in time series analysis compared to MEM when temporal trends are relevant. The AEM approach is logically consistent with temporal autocorrelation where earlier conditions can influence later conditions but not vice versa. The symmetric MEM approach, which ignores the asymmetric nature of time, might be suitable for addressing specific questions about the importance of correlations in fluctuation patterns where there are no confounding elements of linear trends or a need to assess causality. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
|
|
| 5. |
- Baho, Didier Ludovic, et al.
(författare)
-
Microplastics in terrestrial ecosystems: Moving beyond the state of the art to minimize the risk of ecological surprise
- 2021
-
Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 27, s. 3969-3986
-
Tidskriftsartikel (refereegranskat)abstract
- Microplastic (plastic particles measuring <5mm) pollution is ubiquitous. Unlike in other well-studied ecosystems, for example, marine and freshwater environments, microplastics in terrestrial systems are relatively understudied. Their potential impacts on terrestrial environments, in particular the risk of causing ecological surprise, must be better understood and quantified. Ecological surprise occurs when ecosystem behavior deviates radically from expectations and generally has negative consequences for ecosystem services. The properties and behavior of microplastics within terrestrial environments may increase their likelihood of causing ecological surprises as they (a) are highly persistent global pollutants that will last for centuries, (b) can interact with the abiotic environment in a complex manner, (c) can impact terrestrial organisms directly or indirectly and (d) interact with other contaminants and can facilitate their transport. Here, we compiled findings of previous research on microplastics in terrestrial environments. We systematically focused on studies addressing different facets of microplastics related to their distribution, dispersion, impact on soil characteristics and functions, levels of biological organization of tested terrestrial biota (single species vs. assemblages), scale of experimental study and corresponding ecotoxicological effects. Our systematic assessment of previous microplastic research revealed that most studies have been conducted on single species under laboratory conditions with short-term exposures; few studies were conducted under more realistic long-term field conditions and/or with multi-species assemblages. Studies targeting multi-species assemblages primarily considered soil bacterial communities and showed that microplastics can alter essential nutrient cycling functions. More ecologically meaningful studies of terrestrial microplastics encompassing multi-species assemblages, critical ecological processes (e.g., biogeochemical cycles and pollination) and interactions with other anthropogenic stressors must be conducted. Addressing these knowledge gaps will provide a better understanding of microplastics as emerging global stressors and should lower the risk of ecological surprise in terrestrial ecosystems.
|
|
| 6. |
- Collentine, Dennis, et al.
(författare)
-
Realising the potential of natural water retention measures in catchment flood management: trade-offs and matching interests
- 2018
-
Ingår i: Journal of Flood Risk Management. - : Wiley. - 1753-318X. ; 11, s. 76-84
-
Tidskriftsartikel (refereegranskat)abstract
- Natural water retention measures (NWRM) are a multifunctional form of green infrastructure that can play an important role in catchment-scale flood risk management. While green infrastructure based on natural processes is increasingly recognised as being complementary to traditional flood control strategies based on grey infrastructure in urban areas, there are a number of outstanding challenges with their widespread uptake. At a catchment scale, it is widely accepted that NWRM in upstream areas based on the concept of 'keeping the rain where it falls' can help reduce the risk of downstream flooding by enhancing or restoring natural hydrological processes including interception, evapotranspiration, infiltration, and ponding. However, both the magnitude of flood risk reduction and the institutional structures needed for widespread uptake of NWRM are inadequately understood. Implementing NWRM can involve trade-offs, especially in agricultural areas. Measures based on drainage management and short rotation forestry may help 'keep the rain where it falls' but can result in foregone farm income. To identify situations where the implementation of NWRM may be warranted, an improved understanding of the likely reductions in downstream urban flood risk, the required institutional structures for risk management and transfer, and mutually acceptable farm compensation schemes are all needed.
|
|
| 7. |
- Dahlgren Strååt, Kim
(författare)
-
Simulating Transport and Understanding Future Fluxes of Organic Carbon in Rivers Draining into the Baltic Sea
- 2017
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Riverine organic (TOC, Total Organic Carbon) and inorganic (DIC, Dissolved Inorganic Carbon) carbon are the main sources of carbon in the Baltic Sea. While the importance of this contribution has been evaluated, there are currently several gaps in our knowledge of the mechanisms governing organic carbon dynamics in this region, especially for the particulate form, and the impact of future climate change on organic carbon transport. This licentiate thesis addresses this research deficit by (1) developing a model for assessing the flux of particulate organic carbon (POC), and by (2) simulating the potential climate effects on the transport and fate of TOC, both particulate and dissolved organic carbon, in the Baltic Sea environment.Study I developed a novel dynamic model for simulating the generation and transport of POC in all the major rivers discharging into the Baltic Sea. The POC load was assessed using algorithms for the processes governing the input i.e. erosion, litterfall and in-stream primary production. Using daily information on precipitation and temperature, the water discharge from each river was calculated. The total annual POC load from the Baltic Sea drainage basin was predicted within a factor of about 2 and was estimated to be 0.34 Tg POC, or 7-10 % of the annual TOC. The prediction of the timing of the monthly peak loads, however, was hampered by the current lack of field measurements of POC loads to the Baltic Sea.Study II assessed the potential future climate effects on riverine TOC (particulate and dissolved organic carbon, DOC) in the Baltic Sea drainage basin. A small decrease in POC load (-7 %) was predicted and no changes in DOC load on an annual and total basin scale, but the simulations showed significant variations between seasons and across sub-basins by the end of this century. Seasonal total loads were predicted to increase in winter and decrease in summer. Due to counterbalancing increases and decreases in predicted TOC loads in various parts of the Baltic Sea catchment, the impact of climate change on the total carbon budget in this region was limited. However, our simulation results indicated significant differences over time in POC and DOC export across the six Baltic Sea sub-basins, and an altered seasonal pattern in the timing and magnitude of the delivery.This thesis comprises a first attempt to better describe the mechanisms and dynamics of OC generation and transport in the Baltic Sea catchment and assess the potential climate effects on the transport with a spatiotemporal resolution. The work provides a starting point for further development of the understanding of large scale organic carbon export and how it may be affected in the future. This thesis also discuss the role of riverine organic carbon in biogeochemical processes, food web structures and contaminant transport in inland, coastal and marine waters.
|
|
| 8. |
- de Sá, Luis, et al.
(författare)
-
Studies of the effects of microplastics on aquatic organisms: What do we know and where should we focus our efforts in the future?
- 2018
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 645, s. 1029-1039
-
Forskningsöversikt (refereegranskat)abstract
- The effects of microplastics (MP) on aquatic organisms are currently the subject of intense research. Here, we provide a critical perspective on published studies of MP ingestion by aquatic biota. We summarize the available research on MP presence, behaviour and effects on aquatic organisms monitored in the field and on laboratory studies of the ecotoxicological consequences of MP ingestion. We consider MP polymer type, shape, size as well as group of organisms studied and type of effect reported. Specifically, we evaluate whether or not the available laboratory studies of MP are representative of the types of MPs found in the environment and whether or not they have reported on relevant groups or organisms. Analysis of the available data revealed that 1) despite their widespread detection in field-based studies, polypropylene, polyester and polyamide particles were under-represented in laboratory studies; 2) fibres and fragments (800-1600 mu m) are the most common form of MPs reported in animals collected from the field; 3) to date, most studies have been conducted on fish; knowledge is needed about the effects of MPs on other groups of organisms, especially invertebrates. Furthermore, there are significant mismatches between the types of MP most commonly found in the environment or reported in field studies and those used in laboratory experiments. Finally, there is an overarching need to understand the mechanism of action and ecotoxicological effects of environmentally relevant concentrations of MPs on aquatic organism health. (c) 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
|
|
| 9. |
- de Wit, Heleen A., et al.
(författare)
-
Current Browning of Surface Waters Will Be Further Promoted by Wetter Climate
- 2016
-
Ingår i: ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS. - : American Chemical Society (ACS). - 2328-8930. ; 3:12, s. 430-435
-
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.
|
|
| 10. |
- Djodjic, Faruk, et al.
(författare)
-
Cost effectiveness of nutrient retention in constructed wetlands at a landscape level
- 2022
-
Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 324
-
Tidskriftsartikel (refereegranskat)abstract
- Since 1990, over 13 000 ha of constructed wetlands (CWs) have been implemented to increase biodiversity and reduce nitrogen (N) and phosphorus (P) loads to Swedish waters. Despite the considerable number of CWs and ambitious investments planned for the coming three years, there is limited follow up of cost-efficiency of catchment- and landscape-scale nutrient retention by existing CWs. Such follow up evaluation could provide clear guidance regarding optimal size and location of future CWs. We present a three-step modelling approach to assess cost-efficiency of 233 CWs in two Swedish regions (East, 4321 km2, and West, 916 km2). Modelled nutrient retention in CWs was predominantly low, especially in the East, due to their suboptimal location in catchments, e.g., with inadequate upstream areas (low hydraulic loads) and/or low share of arable land (low nutrient loads). Suboptimal location of CWs generates both higher than necessary costs and low area-specific nutrient retention, leading to low cost-efficiency. Some high cost-efficiency CWs were identified, especially for N retention in the West. To increase their cost-efficiency, continued investments in CWs require clear guidance and instructions. To achieve optimal placement, both CW site and size in relation to incoming hydraulic and nutrient loads must be considered.
|
|
| 11. |
- Djodjic, Faruk, et al.
(författare)
-
Suspenderat material –transporter och betydelsen för andra vattenkvalitetsparametrar
- 2012
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Erosion och transport av suspenderat material i vatten är i Sverige sällan av en sådan omfattning att det utgör ett allvarligt storskaligt miljöproblem. I vissa fall kan dock suspenderat material och ökad grumlighet ha direkta negativa effekter på akvatiska ekosystem genom t. ex. påverkan på fisklek, utslagning av filtrerare som t.ex. stormusslor och minskad primärproduktion och därmed minskad födotillgång. Sedimentering av partiklar kan också förändra livsförutsättningarna för bottenfauna vilket kan resultera i förändrad artsammansättning. Dessutom är suspenderat material som bärare av näringsämnen, främst fosfor, och även andra ämnen (som t. ex. metaller, bekämpningsmedel, organiska miljögifter mm) mycket betydelsefull för de totala transporterade mängderna av dessa ämnen. I SMED-kontexten är det intressant att vidare studera transport av suspenderat material eftersom både fosfor-och metalltransporter påverkas av dessa processer.Syftet med denna studie är att sammanställa och utvärdera befintlig litteratur och data över sedimenttransport i Sverige och kopplingar till fosfor och eventuellt andra ämnen samt att försöka fördjupa vår förståelse av transportdynamiken genom att modellera vatten och sedimenttransport.Statistiska signifikanta samband mellan halter och transport av suspenderat materi-al och dominerande jordarter i tillrinningsområden hittades både för små jord-bruksdominerade avrinningsområden och för större områden. Högre andel lerjordar resulterade i högre halter/transporter av suspenderat material vilket tyder på en högre erosionsbenägenhet av lerjordar jämfört med grövre sandjordar. För de större avrinningsområdena fanns även ett positivt och statistiskt signifikant samband med andel åkermark i tillrinningsområdet.Olika angreppssätt med modellering testades för Sävjaåns avrinningsområde. För det första visade en analys av olika delar av den hydrologiska cykeln med hjälp av FyrisQ-modellen på två intressanta samband. Högre halter av suspenderat material var kopplade till perioder då blötare förhållanden rådde i avrinningsområdet samt vid snösmältningsepisoder. För det andra, tillämpades INCA-Sed modellen för första gången i Sverige. Denna tillämpning visar att modellen kan vara användbar för att öka förståelsen av mobilisering och transport av sediment under svenska förhållanden, även om fler studier behövs för att öka tillförlitligheten och minska osäkerheterna
|
|
| 12. |
- Eklöf, Karin, et al.
(författare)
-
Land-use dominates climate controls on nitrogen and phosphorus export from managed and natural Nordic headwater catchments
- 2020
-
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 34, s. 4831-4850
-
Tidskriftsartikel (refereegranskat)abstract
- Agricultural, forestry-impacted and natural catchments are all vectors of nutrient loading in the Nordic countries. Here, we present concentrations and fluxes of total nitrogen (totN) and phosphorus (totP) from 69 Nordic headwater catchments (Denmark: 12, Finland:18, Norway:17, Sweden:22) between 2000 and 2018. Catchments span the range of Nordic climatic and environmental conditions and include natural sites and sites impacted by agricultural and forest management. Concentrations and fluxes of totN and totP were highest in agricultural catchments, intermediate in forestry-impacted and lowest in natural catchments, and were positively related %agricultural land cover and summer temperature. Summer temperature may be a proxy for terrestrial productivity, while %agricultural land cover might be a proxy for catchment nutrient inputs. A regional trend analysis showed significant declines in N concentrations and export across agricultural (-15 mu g totN L-1 year(-1)) and natural (-0.4 mu g NO3-N L-1 year(-1)) catchments, but individual sites displayed few long-term trends in concentrations (totN: 22%, totP: 25%) or export (totN: 6%, totP: 9%). Forestry-impacted sites had a significant decline in totP (-0.1 mu g P L-1 year(-1)). A small but significant increase in totP fluxes (+0.4 kg P km(-2) year(-1)) from agricultural catchments was found, and countries showed contrasting patterns. Trends in annual concentrations and fluxes of totP and totN could not be explained in a straightforward way by changes in runoff or climate. Explanations for the totN decline include national mitigation measures in agriculture international policy to reduced air pollution and, possibly, large-scale increases in forest growth. Mitigation to reduce phosphorus appears to be more challenging than for nitrogen. If the green shift entails intensification of agricultural and forest production, new challenges for protection of water quality will emerge possible exacerbated by climate change. Further analysis of headwater totN and totP export should include seasonal trends, aquatic nutrient species and a focus on catchment nutrient inputs.
|
|
| 13. |
- Eklöf, Karin, et al.
(författare)
-
Parsimonious Model for Simulating Total Mercury and Methylmercury in Boreal Streams Based on Riparian Flow Paths and Seasonality
- 2015
-
Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 49:13, s. 7851-7859
-
Tidskriftsartikel (refereegranskat)abstract
- The complexity of mercury (Hg) biogeochemistry has made it difficult to model surface water concentrations of both total Hg (THg) and especially methylmercury (MeHg), the species of Hg having the highest potential for bioaccumulation. To simulate THg and MeHg variation in low-order streams, we have adapted a conceptual modeling framework where a continuum of lateral flows through riparian soils determines streamflow concentrations. The model was applied to seven forest catchments located in two boreal regions in Sweden spanning a range of climatic, soil, and forest management conditions. Discharge, and simulated riparian soil water concentrations profiles, represented by two calibrated parameters, were able to explain much of the variability of THg and MeHg concentrations in the streams issuing from the catchments (Nash Sutcliffe (NS) up to 0.54 for THg and 0.58 for MeHg). Model performance for all catchments was improved (NS up to 0.76 for THg and 0.85 for MeHg) by adding two to four parameters to represent seasonality in riparian soil water THg and MeHg concentrations profiles. These results are consistent with the hypothesis that riparian flow-pathways and seasonality in riparian soil concentrations are the major controls on temporal variation of THg and MeHg concentrations in low-order streams.
|
|
| 14. |
|
|
| 15. |
- Ellison, David, et al.
(författare)
-
On the forest cover-water yield debate : from demand- to supply-side thinking
- 2012
-
Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 18:3, s. 806-820
-
Forskningsöversikt (refereegranskat)abstract
- Several major articles from the past decade and beyond conclude the impact of reforestation or afforestation on water yield is negative: additional forest cover will reduce and removing forests will raise downstream water availability. A second group of authors argue the opposite: planting additional forests should raise downstream water availability and intensify the hydrologic cycle. Obtaining supporting evidence for this second group of authors has been more difficult due to the larger scales at which the positive effects of forests on the water cycle may be seen. We argue that forest cover is inextricably linked to precipitation. Forest-driven evapotranspiration removed from a particular catchment contributes to the availability of atmospheric moisture vapor and its cross-continental transport, raising the likelihood of precipitation events and increasing water yield, in particular in continental interiors more distant from oceans. Seasonal relationships heighten the importance of this phenomenon. We review the arguments from different scales and perspectives. This clarifies the generally beneficial relationship between forest cover and the intensity of the hydrologic cycle. While evidence supports both sides of the argument trees can reduce runoff at the small catchment scale at larger scales, trees are more clearly linked to increased precipitation and water availability. Progressive deforestation, land conversion from forest to agriculture and urbanization have potentially negative consequences for global precipitation, prompting us to think of forest ecosystems as global public goods. Policy-making attempts to measure product water footprints, estimate the value of ecosystem services, promote afforestation, develop drought mitigation strategies and otherwise manage land use must consider the linkage of forests to the supply of precipitation.
|
|
| 16. |
|
|
| 17. |
- Evans, Chris D., et al.
(författare)
-
Variability in organic carbon reactivity across lake residence time and trophic gradients
- 2017
-
Ingår i: Nature Geoscience. - 1752-0894 .- 1752-0908. ; 10:11, s. 832-835
-
Tidskriftsartikel (refereegranskat)abstract
- The transport of dissolved organic carbon from land to ocean is a large dynamic component of the global carbon cycle. Inland waters are hotspots for organic matter turnover, via both biological and photochemical processes, and mediate carbon transfer between land, oceans and atmosphere. However, predicting dissolved organic carbon reactivity remains problematic. Here we present in situ dissolved organic carbon budget data from 82 predominantly European and North American water bodies with varying nutrient concentrations and water residence times ranging from one week to 700 years. We find that trophic status strongly regulates whether water bodies act as net dissolved organic carbon sources or sinks, and that rates of both dissolved organic carbon production and consumption can be predicted from water residence time. Our results suggest a dominant role of rapid light-driven removal in water bodies with a short water residence time, whereas in water bodies with longer residence times, slower biotic production and consumption processes are dominant and counterbalance one another. Eutrophication caused lakes to transition from sinks to sources of dissolved organic carbon. We conclude that rates and locations of dissolved organic carbon processing and associated CO2 emissions in inland waters may be misrepresented in global carbon budgets if temporal and spatial reactivity gradients are not accounted for.
|
|
| 18. |
- Fried-Petersen, Hannah, et al.
(författare)
-
Drivers of long-term invertebrate community stability in changing Swedish lakes
- 2020
-
Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 26, s. 1259-1270
-
Tidskriftsartikel (refereegranskat)abstract
- Research on ecosystem stability has had a strong focus on local systems. However, environmental change often occurs slowly at broad spatial scales, which requires regional-level assessments of long-term stability. In this study, we assess the stability of macroinvertebrate communities across 105 lakes in the Swedish "lakescape." Using a hierarchical mixed-model approach, we first evaluate the environmental pressures affecting invertebrate communities in two ecoregions (north, south) using a 23 year time series (1995-2017) and then examine how a set of environmental and physical variables affect the stability of these communities. Results show that lake latitude, size, total phosphorus and alkalinity affect community composition in northern and southern lakes. We find that lake stability is affected by species richness and lake size in both ecoregions and alkalinity and total phosphorus in northern lakes. There is large heterogeneity in the patterns of community stability of individual lakes, but relationships between that stability and environmental drivers begin to emerge when the lakescape, composed of many discrete lakes, is the focal unit of study. The results of this study highlight that broad-scale comparisons in combination with long time series are essential to understand the effects of environmental change on the stability of lake communities in space and time.
|
|
| 19. |
- Futter, Martyn
(författare)
-
A cost-effectiveness analysis of water security and water quality: impacts of climate and land-use change on the River Thames system
- 2013
-
Ingår i: Philosophical Transactions A: Mathematical, Physical and Engineering Sciences. - : The Royal Society. - 1364-503X .- 1471-2962. ; 371
-
Tidskriftsartikel (refereegranskat)abstract
- The catchment of the River Thames, the principal river system in southern England, provides the main water supply for London but is highly vulnerable to changes in climate, land use and population. The river is eutrophic with significant algal blooms with phosphorus assumed to be the primary chemical indicator of ecosystem health. In the Thames Basin, phosphorus is available from point sources such as wastewater treatment plants and from diffuse sources such as agriculture. In order to predict vulnerability to future change, the integrated catchments model for phosphorus (INCA-P) has been applied to the river basin and used to assess the cost-effectiveness of a range of mitigation and adaptation strategies. It is shown that scenarios of future climate and land-use change will exacerbate the water quality problems, but a range of mitigation measures can improve the situation. A cost-effectiveness study has been undertaken to compare the economic benefits of each mitigation measure and to assess the phosphorus reductions achieved. The most effective strategy is to reduce fertilizer use by 20% together with the treatment of effluent to a high standard. Such measures will reduce the instream phosphorus concentrations to close to the EU Water Framework Directive target for the Thames.
|
|
| 20. |
- Futter, Martyn
(författare)
-
A theoretical assessment of microplastic transport in river catchments and their retention by soils and river sediments
- 2016
-
Ingår i: Environmental Science: Processes and Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 18, s. 1050-1059
-
Tidskriftsartikel (refereegranskat)abstract
- The presence of microplastics (MPs) in the environment is a problem of growing concern. While research has focused on MP occurrence and impacts in the marine environment, very little is known about their release on land, storage in soils and sediments and transport by run-off and rivers. This study describes a first theoretical assessment of these processes. A mathematical model of catchment hydrology, soil erosion and sediment budgets was upgraded to enable description of MP fate. The Thames River in the UK was used as a case study. A general lack of data on MP emissions to soils and rivers and the mass of MPs in agricultural soils, limits the present work to serve as a purely theoretical, nevertheless rigorous, assessment that can be used to guide future monitoring and impact evaluations. The fundamental assumption on which modelling is based is that the same physical controls on soil erosion and natural sediment transport (for which model calibration and validation are possible), also control MP transport and storage. Depending on sub-catchment soil characteristics and precipitation patterns, approximately 16-38% of the heavier-than-water MPs hypothetically added to soils (e.g. through routine applications of sewage sludge) are predicted to be stored locally. In the stream, MPs < 0.2 mm are generally not retained, regardless of their density. Larger MPs with densities marginally higher than water can instead be retained in the sediment. It is, however, anticipated that high flow periods can remobilize this pool. Sediments of river sections experiencing low stream power are likely hotspots for deposition of MPs. Exposure and impact assessments should prioritize these environments.
|
|
| 21. |
- Futter, Martyn
(författare)
-
Almost 50 years of monitoring shows that climate, not forestry, controls long-term organic carbon fluxes in a large boreal watershed
- 2014
-
Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 20, s. 1225-1237
-
Tidskriftsartikel (refereegranskat)abstract
- Here, we use a unique long-term data set on total organic carbon (TOC) fluxes, its climatic drivers and effects of land management from a large boreal watershed in northern Finland. TOC and runoff have been monitored at several sites in the Simojoki watershed (3160km(2)) since the early 1960s. Annual TOC fluxes have increased significantly together with increased inter-annual variability. Acid deposition in the area has been low and has not significantly influenced losses of TOC. Forest management, including ditching and clear felling, had a minor influence on TOC fluxes - seasonal and long-term patterns in TOC were controlled primarily by changes in soil frost, seasonal precipitation, drought, and runoff. Deeper soil frost led to lower spring TOC concentrations in the river. Summer TOC concentrations were positively correlated with precipitation and soil moisture not temperature. There is some indication that drought conditions led to elevated TOC concentrations and fluxes in subsequent years (1998-2000). A sensitivity analysis of the INCA-C model results showed the importance of landscape position, land-use type, and soil temperature as controls of modeled TOC concentrations. Model predictions were not sensitive to forest management. Our results are contradictory to some earlier plot-scale and small catchment studies that have shown more profound forest management impacts on TOC fluxes. This shows the importance of scale when assessing the mechanisms controlling TOC fluxes and concentrations. The results highlight the value of long-term multiple data sets to better understand ecosystem response to land management, climate change and extremes in northern ecosystems.
|
|
| 22. |
- Futter, Martyn
(författare)
-
An INCA model for pathogens in rivers and catchments: Model structure, sensitivity analysis and application to the River Thames catchment, UK
- 2016
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 572, s. 1601-1610
-
Tidskriftsartikel (refereegranskat)abstract
- Pathogens are an ongoing issue for catchment water management and quantifying their transport, loss and potential impacts at key locations, such as water abstractions for public supply and bathing sites, is an important aspect of catchment and coastal management. The Integrated Catchment Model (INCA) has been adapted to model the sources and sinks of pathogens and to capture the dominant dynamics and processes controlling pathogens in catchments. The model simulates the stores of pathogens in soils, sediments, rivers and groundwaters and can account for diffuse inputs of pathogens from agriculture, urban areas or atmospheric deposition. The model also allows for point source discharges from intensive livestock units or from sewage treatment works or any industrial input to river systems. Model equations are presented and the new pathogens model has been applied to the River Thames in order to assess total coliform (TC) responses under current and projected future land use. A Monte Carlo sensitivity analysis indicates that the input coliform estimates from agricultural sources and decay rates are the crucial parameters controlling pathogen behaviour. Whilst there are a number of uncertainties associated with the model that should be accounted for, INCA-Pathogens potentially provides a useful tool to inform policy decisions and manage pathogen loading in river systems. (C) 2016 Elsevier B.V. All rights reserved.
|
|
| 23. |
|
|
| 24. |
- Futter, Martyn
(författare)
-
Assessing the impacts of climate change and socio-economic changes on flow and phosphorus flux in the Ganga river system
- 2015
-
Ingår i: Environmental Science: Processes and Impacts. - : Royal Society of Chemistry (RSC). - 2050-7887 .- 2050-7895. ; 17, s. 1098-1110
-
Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic climate change has impacted and will continue to impact the natural environment and people around the world. Increasing temperatures and altered rainfall patterns combined with socio-economic factors such as population changes, land use changes and water transfers will affect flows and nutrient fluxes in river systems. The Ganga river, one of the largest river systems in the world, supports approximately 10% global population and more than 700 cities. Changes in the Ganga river system are likely to have a significant impact on water availability, water quality, aquatic habitats and people. In order to investigate these potential changes on the flow and water quality of the Ganga river, a multi-branch version of INCA Phosphorus (INCA-P) model has been applied to the entire river system. The model is used to quantify the impacts from a changing climate, population growth, additional agricultural land, pollution control and water transfers for 2041-2060 and 2080-2099. The results provide valuable information about potential effects of different management strategies on catchment water quality.
|
|
| 25. |
- Futter, Martyn
(författare)
-
Assessment of contaminant fate in catchments using a novel integrated hydrobiogeochemical-multimedia fate model
- 2016
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 544, s. 553-563
-
Tidskriftsartikel (refereegranskat)abstract
- Models for pollution exposure assessment typically adopt an overly simplistic representation of geography, climate and biogeochemical processes. This strategy is unsatisfactory when high temporal resolution simulations for sub-regional spatial domains are performed, in which parameters defining scenarios can vary interdependently in space and time. This is, for example, the case when assessing the influence of biogeochemical processing on contaminant fate. Here we present INCA-Contaminants, the Integrated Catchments model for Contaminants; a new model that simultaneously and realistically solves mass balances of water, carbon, sediments and contaminants in the soil-stream-sediment system of catchments and their river networks as a function of climate, land use/management and contaminant properties. When forced with realistic climate and contaminant input data, the model was able to predict polychlorinated biphenyls (PCBs) concentrations in multiple segments of a river network in a complex landscape. We analyzed model output sensitivity to a number of hydro-biogeochemical parameters. The rate of soil organic matter mineralization was the most sensitive parameter controlling PCBs levels in river water, supporting the hypothesis that organic matter turnover rates will influence remobilization of previously deposited PCBs which had accumulated in soil organic matrix. The model was also used to project the long term fate of PCB 101 under two climate scenarios. Catchment diffuse run-off and riverine transport were the major pathways of contaminant re-mobilization. Simulations show that during the next decade the investigated boreal catchment will shift from being a net atmospheric PCB sink to a net source for air and water, with future climate perturbation having little influence on this trend. Our results highlight the importance of using credible hydro-biogeochemical simulations when modeling the fate of hydrophobic contaminants. (C) 2015 Elsevier B.V. All rights reserved.
|
|
