Anders Wilander - Academia.edu (original) (raw)

Papers by Anders Wilander

Medelantalet taxa för hela landet var 21,6 och låg nära medianen på 21,0 taxa, medan 10 och 90 pe... more Medelantalet taxa för hela landet var 21,6 och låg nära medianen på 21,0 taxa, medan 10 och 90 percentilerna var 12 och 32 taxa (tabell 44). Percentilerna säger mer än medelvärdet om det intervall inom vilket större

Water Research, Dec 1, 1974

A modified fluorometric method for the determination of lignin sulfonate in natural water is desc... more A modified fluorometric method for the determination of lignin sulfonate in natural water is described. The optimum wavelengths for excitation and emission were found at 285 and 405 nm respectively. A low interference from natural compounds, especially humic substances, has been attained. The application of the method to a filter fluorometer for in situ measurements is described together with some test results.

Bilaga 1. Provtagningsplatsernas lägeskoordinater Bilaga 2. Vattenkemiska analysmetoder Bilaga 3.... more Bilaga 1. Provtagningsplatsernas lägeskoordinater Bilaga 2. Vattenkemiska analysmetoder Bilaga 3. Analysresultat för vattenkemi-tabeller Bilaga 4. Analysresultat för vattenkemi-figurer Bilaga 5. Ämnestransporter och arealspecifika förluster-tabeller Bilaga 6. Ämnestransporter-figurer Bilaga 7. Syrgas-och temperaturprofiler-figurer Bilaga 8. Växtplankton-biovolymer Bilaga 9. Bottenfauna-tätheter och biomassor Bilaga 10. Resultat från provfiske inkl kvicksilver-och metallhalter i fisk-7-Under perioder med stabil temperatur skiktning uppträder ibland dåliga syrgasförhållanden framförallt i de mer näringsrika sjöarna fr o m Södra Barken och nedströms i vattensystemet. Med undantag för tillfällen med förhållandevis låga syrgashalter i de mindre sjöarna i den övre delen av åsystemet, är syrgasförhållandena överlag goda i Kolbäcksåns sjöar. Kolbäcksåns sjöar och vattendrag har i allmänhet en god buffertkapacitet. Endast i den övre delen av vattensystemet förekommer period vis låga pH-värden och låg alkalinitet i bl a Pellabäcken och Saxen, vilka ligger i några av de få områden inom vatten systemet som inte kalkas eller har kalkats tidigare. Metallföroreningsmönstret i sjöarnas vatten och de metallmängder som transporteras igenom vattensystemet följer varandra väl. Saxen är den mest metallförorenade sjön, med förhöjda halter av koppar, zink, bly och kadmium, vilket beror på den tidigare gruvdriften i Saxdalen. Saxens påverkan på resten av Kolbäcksån varierar mycket mellan olika metaller, men generellt kan man säga att de mer lättrörliga metallerna zink och kadmium har en större och mer vidsträckt påverkan än mer svårrörliga metaller som bly och koppar, vilka tenderar att stanna kvar lokalt i sjöns sedimenten. Förhöjda halter av flera metaller återfinns även stundtals i Stora Aspens botten vatten i samband med dåliga syrgasförhållanden och låga pH-värden i augusti. Legeringsmetallerna krom, nickel, kobolt och volfram tillförs vattnet framförallt i systemets nedre industritäta del. Växtplanktonbiovolymerna i Kolbäcksåns sjöar var i år överlag på en förhållandevis normal nivå. De högsta biomassorna uppnåddes som vanligt i de näringsrikaste sjöar i systemet, dvs Trättens södra bassäng (Trätten S), Stora Aspen och Östersjön. Kisel alger var generellt sett den viktigaste planktongruppen, men även guld-och rekylalger utgjorde ett betydande inslag. Cyanobakterier (blågrönalger) var däremot vanliga i St. Aspen. Årets bottenfauna sammansättning i sjöarnas strandzoner (litoral) uppvisade i år färre antal taxa, men med en artsammansättning som är normal för sjöarna. Även tätheterna på sjöarnas djupbottnar (profundalzoner) var överlag lägre i år jämfört med de höga tätheterna under fjolåret. Provfiskeresultaten och metallanalyserna visar sammantaget på likartade resultat jämfört med den tidigare undersökningen 1996. Totalt erhölls 2 734 fiskar fördelade på 12 arter. De vanligaste arterna var abborre och mört, vilka fångades i samtliga sjöar. Andra vanliga arter var gers, björkna och braxen, medan nors, siklöja, gös, lake, gädda, asp och löja förekom i mer begränsad omfattning. Tre exemplar av den rödlistade arten asp fångades i Östersjön. Endast tre stycken gäddor fångades, varför kvicksilveranalyserna kompletterades med prov från gös och abborre. De största fiskfångsterna såväl antals-som viktmässigt erhölls i de två mest näringsrika sjöarna Östersjön och Stora Aspen. I dessa sjöar utgjorde karpfiskar (vitfiskar) hälften eller mer av vikten i näten, vilket är vanligt i näringsrika sjöar. Kvicksilverhalten i abborrmuskel från Övre Hillen var något högre än halten i fisk från de övriga sjöarna. Halterna i abborre som är större än ca 20 cm från denna sjö är nära det gällande gränsvärdet för saluförande på 0,5 mg/kg. Jämförelsevis höga halter av koppar, zink, kadmium och bly återfanns i abborrlever från Saxen, vilket överensstämmer med de höga halterna av dessa metaller i Saxens sediment. I sedimentundersökningen 2001 noterades även förhöjda halter av nickel, kobolt och volfram i St. Aspen och sjöarna nedströms, vilket även speglas i jämförelsevis högre halter av nickel och volfram i fisken från St. Aspen, Åmänningen och Östersjön.

Behavior Therapy, 1978

Interval DRL, a procedure by which reinforcement is delivered at the end of an interval if one or... more Interval DRL, a procedure by which reinforcement is delivered at the end of an interval if one or no responses have occurred, was used to reduce inappropriate classroom behavior in two separate studies. In Experiment I, a variety of inappropriate behaviors by one male learning-disabled student was reduced when stars, exchangeable for free time, were made contingent on short intervals in which fewer than two responses occurred. Inappropriate talk-outs were reduced in a group of 14 5-year-old handicapped children when minutes of access to a sand table were made contingent on two or fewer responses per interval in Experiment II.

The three Nordic countries Finland, Norway and Sweden decided to carry out a joint Nordic Lake Su... more The three Nordic countries Finland, Norway and Sweden decided to carry out a joint Nordic Lake Survey in the fall of 1995. A working group, supported financially by the Nordic Council of Ministers (NMR), prepared a common manual for this purpose. It was decided to use similar lake selection criteria and harmonized analytical procedures. Generally, lakes in Denmark are not sensitive to acidification, but most lakes are strongly affected by nutrients. Thus , lake surveys like those carried out in the other Nordic countries have not been undertaken in this country. NMR has asked for a common evaluation of the properties of the lake populations in the four countries. As a result of Norwegian-Finnish-Swedish-Russian initiatives lake surveys were also carried out concurrently in Northern Kola and the Russian Karelia with financial support from Finland, Norway and Sweden. The working group also asked the United Kingdom to joint in a common lake survey. As a result a lake survey was concurrently carried out in Scotland and Wales using similar lake selection criterias as those used for the surveys in Finland, Norway and Sweden. This report presents the coordination and the design og the surveys. A second report will present and discuss the results.Nordic Council of Minister

Springer eBooks, 1995

On average, pH rose from 5.88 to 6.56 after liming. Only in The consequences of liming on water c... more On average, pH rose from 5.88 to 6.56 after liming. Only in The consequences of liming on water chemistry are presented in terms both of the primary changes in pH, calcium and alkalinity and of secondary effects such as the impact on levels of organic materials, nutrients and trace metals. Data for the evaluation have mainly been drawn from the liming data base (KRUT), which is maintained by Swedish county councils and the Swedish Environmental Protection Agency. The condition of limed waters in Sweden and the changes which are taking place in these waters can be described in objective terms and subjected to international comparison.

Water Research, Apr 1, 2000

ÐOrganic acid dissociation has usually been estimated from the dierence between measured cations ... more ÐOrganic acid dissociation has usually been estimated from the dierence between measured cations and anions (the anion de®cit approach). An alternative is to use alkalinity titrations and an estimate of strong organic acids from TOC as an independent measure of organic acid dissociation (the CBALK approach). This approach may reduce the potential for errors relative to the anion de®cit approach, which relies on summing up all measured constituents. Organic acid dissociation in a set of Swedish surface water samples from 700 dierent lakes, as well as 200 samples from 11 streams was predicted using a triprotic analogue model with buering characteristics similar to those of the widely used``Oliver'' model (OTM), but with a lower site density of organic acids. The average equilibrium pH of the samples in the weakly buered pH range of 4.7±6.7 could be predicted more precisely (20.16 pH units) using the CBALK approach, than when using the usual anion de®cit approach (20.41 pH units). The study supports the general applicability of models similar to the empirical OTM for predicting the dissociation of natural organic acids on a regional scale.

AMBIO: A Journal of the Human Environment, Dec 1, 2001

In-lake concentration changes of phosphorus (P) and nitrogen (N) in lakes Vättern, Vänern, Mälare... more In-lake concentration changes of phosphorus (P) and nitrogen (N) in lakes Vättern, Vänern, Mälaren, and Hjälmaren in response to diminished input has been examined from the mid-1960s onwards. In the former two deep and oligotrophic lakes with slow water renewal, drastic reductions in P-input from the middle of 1970s caused just minor reductions in P-concentration over a very long time. At the same time accumulation occurred in the water mass of inorganic N and possible reasons are discussed. In the latter two mesotrophic to hypertrophic lakes, two shallow basins in L. Hjälmaren showed slow recovery due to release of P from sediments. The same basins and two basins in L. Mälaren have suffered from N-deficiency, particularly during the pre-phosphorus reduction years, and nitrogen fixation was indicated. In two L. Mälaren basins recovery of in-lake P concentrations was better than expected in comparison to the so-called IMSA-model for lake recovery from nutrient pollution. In the other five lakes/ basins chlorophyll concentrations after 20 years were similar compared to those modeled.

SammanfattningUtvarderingen omfattar kemiska variabler (forsurningsparametrar, naringsamnen, syre... more SammanfattningUtvarderingen omfattar kemiska variabler (forsurningsparametrar, naringsamnen, syre ochsyretarande amnen, ljusforhallanden samt viktiga an- och katjoner) i lanets tidseriesjoar och -v ...

Springer eBooks, 1995

Lake Gardsjon and its catchment area have been studied since the early 1970s and have, along with... more Lake Gardsjon and its catchment area have been studied since the early 1970s and have, along with other lakes in the vicinity, been the target of the greatest individual Swedish effort in the field of acidification and liming research. The majority of studies in the lake itself were concluded in the early 1990s, but some still continue to a limited extent today.

Limnology and Oceanography, Dec 1, 2000

Here we report on the role of natural (lakes) and artificial barriers (dams) in regulating dissol... more Here we report on the role of natural (lakes) and artificial barriers (dams) in regulating dissolved silicate (DSi) concentrations in rivers from Sweden and Finland. Concentrations of DSi and total phosphorus in rivers were strongly affected by the presence of lakes and reservoirs along the aquatic continuum, with riverine DSi concentrations decreasing as the percentage of area occupied by lakes and reservoirs increased. Rivers with Ͻ2% lake and reservoir area in their watershed averaged 164 M, whereas DSi in rivers containing greater than 10% lake and reservoir area averaged 46 M. The relationship between percentage lake area and DSi concentration was best fit by an exponential function (r 2 ϭ 0.79, P Ͻ 0.001), because once lake and reservoir area exceeds 10%, minimum DSi concentrations are reached. Because lakes and reservoirs act to reduce watershed DSi concentrations through diatom growth and sedimentation, our results support the hypothesis that further declines in the delivery of DSi to the coastal ocean should be expected as new dams are constructed on rivers. These reductions in DSi transport to the coastal zone with dam construction will have important repercussions on diatom growth and coastal food webs.

Verhandlungen, Mar 1, 1985

Schweizerische Zeitschrift für Hydrologie, Hydrobiologie, Limnologie, Fischereiwissenschaft, Abwasserreinigung, Sep 1, 1972

Diaflo ultrafilters have been studied for the fractionation of organic matter in natural water. O... more Diaflo ultrafilters have been studied for the fractionation of organic matter in natural water. One method for their use, including pretreatment, is described. The filter retention is not only depending on the weight of the molecule but also on the charge as shown by experiments with dyestuffs and inorganic ions. For pure solutions of phosphate and nitrate the retentions were

Verhandlungen, Mar 1, 2006

Verhandlungen, Sep 1, 2005

Environmental Monitoring and Assessment, Jun 2, 2006

To abate the severe acidification of Swedish lakes are about 7% directly limed (AL-lakes). These ... more To abate the severe acidification of Swedish lakes are about 7% directly limed (AL-lakes). These are important to include when assessing acidification. Consequently, we need to estimate their chemical status as if they were not lime-affected. We hypothesize that there is a spatial dependence for calcium (Ca) and magnesium (Mg) concentrations. Spatial variation is determined using variograms. We study lakes within two 150 * 150 km quadrates (EMEP150-grid) in the middle and southern parts of Sweden. We model Ca in AL-lakes using the Ca and Mg concentrations in nearby, unaffected lakes (UL-lakes). The mean Ca/Mg for the three or seven closest UL-lakes is used. We assume that Ca/Mg is constant for UL-lakes and that Mg unaltered by liming. For UL-lakes, Ca and Mg are spatially dependent. For AL-lakes, there is a spatial dependence for Mg, but, as anticipated, not for Ca. The modeled Ca for UL-lakes show a good correspondence with measured Ca; r 2 > 0.6; slopes close to 1 and intercepts almost 0. Using three or seven nearby lakes when modeling Ca give similar results. Modeled Ca was higher than measured Ca for 36% (three closest lakes) and 38% (seven closest) of the modeled AL-lakes in the middle part of Sweden. The corresponding results for the southern part were 10% and 9%, respectively. This model is an acceptable estimator of Ca in limed lakes and for estimating critical loads and acidification status on an EMEP-scale.

Medelantalet taxa för hela landet var 21,6 och låg nära medianen på 21,0 taxa, medan 10 och 90 pe... more Medelantalet taxa för hela landet var 21,6 och låg nära medianen på 21,0 taxa, medan 10 och 90 percentilerna var 12 och 32 taxa (tabell 44). Percentilerna säger mer än medelvärdet om det intervall inom vilket större

Water Research, Dec 1, 1974

A modified fluorometric method for the determination of lignin sulfonate in natural water is desc... more A modified fluorometric method for the determination of lignin sulfonate in natural water is described. The optimum wavelengths for excitation and emission were found at 285 and 405 nm respectively. A low interference from natural compounds, especially humic substances, has been attained. The application of the method to a filter fluorometer for in situ measurements is described together with some test results.

Bilaga 1. Provtagningsplatsernas lägeskoordinater Bilaga 2. Vattenkemiska analysmetoder Bilaga 3.... more Bilaga 1. Provtagningsplatsernas lägeskoordinater Bilaga 2. Vattenkemiska analysmetoder Bilaga 3. Analysresultat för vattenkemi-tabeller Bilaga 4. Analysresultat för vattenkemi-figurer Bilaga 5. Ämnestransporter och arealspecifika förluster-tabeller Bilaga 6. Ämnestransporter-figurer Bilaga 7. Syrgas-och temperaturprofiler-figurer Bilaga 8. Växtplankton-biovolymer Bilaga 9. Bottenfauna-tätheter och biomassor Bilaga 10. Resultat från provfiske inkl kvicksilver-och metallhalter i fisk-7-Under perioder med stabil temperatur skiktning uppträder ibland dåliga syrgasförhållanden framförallt i de mer näringsrika sjöarna fr o m Södra Barken och nedströms i vattensystemet. Med undantag för tillfällen med förhållandevis låga syrgashalter i de mindre sjöarna i den övre delen av åsystemet, är syrgasförhållandena överlag goda i Kolbäcksåns sjöar. Kolbäcksåns sjöar och vattendrag har i allmänhet en god buffertkapacitet. Endast i den övre delen av vattensystemet förekommer period vis låga pH-värden och låg alkalinitet i bl a Pellabäcken och Saxen, vilka ligger i några av de få områden inom vatten systemet som inte kalkas eller har kalkats tidigare. Metallföroreningsmönstret i sjöarnas vatten och de metallmängder som transporteras igenom vattensystemet följer varandra väl. Saxen är den mest metallförorenade sjön, med förhöjda halter av koppar, zink, bly och kadmium, vilket beror på den tidigare gruvdriften i Saxdalen. Saxens påverkan på resten av Kolbäcksån varierar mycket mellan olika metaller, men generellt kan man säga att de mer lättrörliga metallerna zink och kadmium har en större och mer vidsträckt påverkan än mer svårrörliga metaller som bly och koppar, vilka tenderar att stanna kvar lokalt i sjöns sedimenten. Förhöjda halter av flera metaller återfinns även stundtals i Stora Aspens botten vatten i samband med dåliga syrgasförhållanden och låga pH-värden i augusti. Legeringsmetallerna krom, nickel, kobolt och volfram tillförs vattnet framförallt i systemets nedre industritäta del. Växtplanktonbiovolymerna i Kolbäcksåns sjöar var i år överlag på en förhållandevis normal nivå. De högsta biomassorna uppnåddes som vanligt i de näringsrikaste sjöar i systemet, dvs Trättens södra bassäng (Trätten S), Stora Aspen och Östersjön. Kisel alger var generellt sett den viktigaste planktongruppen, men även guld-och rekylalger utgjorde ett betydande inslag. Cyanobakterier (blågrönalger) var däremot vanliga i St. Aspen. Årets bottenfauna sammansättning i sjöarnas strandzoner (litoral) uppvisade i år färre antal taxa, men med en artsammansättning som är normal för sjöarna. Även tätheterna på sjöarnas djupbottnar (profundalzoner) var överlag lägre i år jämfört med de höga tätheterna under fjolåret. Provfiskeresultaten och metallanalyserna visar sammantaget på likartade resultat jämfört med den tidigare undersökningen 1996. Totalt erhölls 2 734 fiskar fördelade på 12 arter. De vanligaste arterna var abborre och mört, vilka fångades i samtliga sjöar. Andra vanliga arter var gers, björkna och braxen, medan nors, siklöja, gös, lake, gädda, asp och löja förekom i mer begränsad omfattning. Tre exemplar av den rödlistade arten asp fångades i Östersjön. Endast tre stycken gäddor fångades, varför kvicksilveranalyserna kompletterades med prov från gös och abborre. De största fiskfångsterna såväl antals-som viktmässigt erhölls i de två mest näringsrika sjöarna Östersjön och Stora Aspen. I dessa sjöar utgjorde karpfiskar (vitfiskar) hälften eller mer av vikten i näten, vilket är vanligt i näringsrika sjöar. Kvicksilverhalten i abborrmuskel från Övre Hillen var något högre än halten i fisk från de övriga sjöarna. Halterna i abborre som är större än ca 20 cm från denna sjö är nära det gällande gränsvärdet för saluförande på 0,5 mg/kg. Jämförelsevis höga halter av koppar, zink, kadmium och bly återfanns i abborrlever från Saxen, vilket överensstämmer med de höga halterna av dessa metaller i Saxens sediment. I sedimentundersökningen 2001 noterades även förhöjda halter av nickel, kobolt och volfram i St. Aspen och sjöarna nedströms, vilket även speglas i jämförelsevis högre halter av nickel och volfram i fisken från St. Aspen, Åmänningen och Östersjön.

Behavior Therapy, 1978

Interval DRL, a procedure by which reinforcement is delivered at the end of an interval if one or... more Interval DRL, a procedure by which reinforcement is delivered at the end of an interval if one or no responses have occurred, was used to reduce inappropriate classroom behavior in two separate studies. In Experiment I, a variety of inappropriate behaviors by one male learning-disabled student was reduced when stars, exchangeable for free time, were made contingent on short intervals in which fewer than two responses occurred. Inappropriate talk-outs were reduced in a group of 14 5-year-old handicapped children when minutes of access to a sand table were made contingent on two or fewer responses per interval in Experiment II.

The three Nordic countries Finland, Norway and Sweden decided to carry out a joint Nordic Lake Su... more The three Nordic countries Finland, Norway and Sweden decided to carry out a joint Nordic Lake Survey in the fall of 1995. A working group, supported financially by the Nordic Council of Ministers (NMR), prepared a common manual for this purpose. It was decided to use similar lake selection criteria and harmonized analytical procedures. Generally, lakes in Denmark are not sensitive to acidification, but most lakes are strongly affected by nutrients. Thus , lake surveys like those carried out in the other Nordic countries have not been undertaken in this country. NMR has asked for a common evaluation of the properties of the lake populations in the four countries. As a result of Norwegian-Finnish-Swedish-Russian initiatives lake surveys were also carried out concurrently in Northern Kola and the Russian Karelia with financial support from Finland, Norway and Sweden. The working group also asked the United Kingdom to joint in a common lake survey. As a result a lake survey was concurrently carried out in Scotland and Wales using similar lake selection criterias as those used for the surveys in Finland, Norway and Sweden. This report presents the coordination and the design og the surveys. A second report will present and discuss the results.Nordic Council of Minister

Springer eBooks, 1995

On average, pH rose from 5.88 to 6.56 after liming. Only in The consequences of liming on water c... more On average, pH rose from 5.88 to 6.56 after liming. Only in The consequences of liming on water chemistry are presented in terms both of the primary changes in pH, calcium and alkalinity and of secondary effects such as the impact on levels of organic materials, nutrients and trace metals. Data for the evaluation have mainly been drawn from the liming data base (KRUT), which is maintained by Swedish county councils and the Swedish Environmental Protection Agency. The condition of limed waters in Sweden and the changes which are taking place in these waters can be described in objective terms and subjected to international comparison.

Water Research, Apr 1, 2000

ÐOrganic acid dissociation has usually been estimated from the dierence between measured cations ... more ÐOrganic acid dissociation has usually been estimated from the dierence between measured cations and anions (the anion de®cit approach). An alternative is to use alkalinity titrations and an estimate of strong organic acids from TOC as an independent measure of organic acid dissociation (the CBALK approach). This approach may reduce the potential for errors relative to the anion de®cit approach, which relies on summing up all measured constituents. Organic acid dissociation in a set of Swedish surface water samples from 700 dierent lakes, as well as 200 samples from 11 streams was predicted using a triprotic analogue model with buering characteristics similar to those of the widely used``Oliver'' model (OTM), but with a lower site density of organic acids. The average equilibrium pH of the samples in the weakly buered pH range of 4.7±6.7 could be predicted more precisely (20.16 pH units) using the CBALK approach, than when using the usual anion de®cit approach (20.41 pH units). The study supports the general applicability of models similar to the empirical OTM for predicting the dissociation of natural organic acids on a regional scale.

AMBIO: A Journal of the Human Environment, Dec 1, 2001

In-lake concentration changes of phosphorus (P) and nitrogen (N) in lakes Vättern, Vänern, Mälare... more In-lake concentration changes of phosphorus (P) and nitrogen (N) in lakes Vättern, Vänern, Mälaren, and Hjälmaren in response to diminished input has been examined from the mid-1960s onwards. In the former two deep and oligotrophic lakes with slow water renewal, drastic reductions in P-input from the middle of 1970s caused just minor reductions in P-concentration over a very long time. At the same time accumulation occurred in the water mass of inorganic N and possible reasons are discussed. In the latter two mesotrophic to hypertrophic lakes, two shallow basins in L. Hjälmaren showed slow recovery due to release of P from sediments. The same basins and two basins in L. Mälaren have suffered from N-deficiency, particularly during the pre-phosphorus reduction years, and nitrogen fixation was indicated. In two L. Mälaren basins recovery of in-lake P concentrations was better than expected in comparison to the so-called IMSA-model for lake recovery from nutrient pollution. In the other five lakes/ basins chlorophyll concentrations after 20 years were similar compared to those modeled.

SammanfattningUtvarderingen omfattar kemiska variabler (forsurningsparametrar, naringsamnen, syre... more SammanfattningUtvarderingen omfattar kemiska variabler (forsurningsparametrar, naringsamnen, syre ochsyretarande amnen, ljusforhallanden samt viktiga an- och katjoner) i lanets tidseriesjoar och -v ...

Springer eBooks, 1995

Lake Gardsjon and its catchment area have been studied since the early 1970s and have, along with... more Lake Gardsjon and its catchment area have been studied since the early 1970s and have, along with other lakes in the vicinity, been the target of the greatest individual Swedish effort in the field of acidification and liming research. The majority of studies in the lake itself were concluded in the early 1990s, but some still continue to a limited extent today.

Limnology and Oceanography, Dec 1, 2000

Here we report on the role of natural (lakes) and artificial barriers (dams) in regulating dissol... more Here we report on the role of natural (lakes) and artificial barriers (dams) in regulating dissolved silicate (DSi) concentrations in rivers from Sweden and Finland. Concentrations of DSi and total phosphorus in rivers were strongly affected by the presence of lakes and reservoirs along the aquatic continuum, with riverine DSi concentrations decreasing as the percentage of area occupied by lakes and reservoirs increased. Rivers with Ͻ2% lake and reservoir area in their watershed averaged 164 M, whereas DSi in rivers containing greater than 10% lake and reservoir area averaged 46 M. The relationship between percentage lake area and DSi concentration was best fit by an exponential function (r 2 ϭ 0.79, P Ͻ 0.001), because once lake and reservoir area exceeds 10%, minimum DSi concentrations are reached. Because lakes and reservoirs act to reduce watershed DSi concentrations through diatom growth and sedimentation, our results support the hypothesis that further declines in the delivery of DSi to the coastal ocean should be expected as new dams are constructed on rivers. These reductions in DSi transport to the coastal zone with dam construction will have important repercussions on diatom growth and coastal food webs.

Verhandlungen, Mar 1, 1985

Schweizerische Zeitschrift für Hydrologie, Hydrobiologie, Limnologie, Fischereiwissenschaft, Abwasserreinigung, Sep 1, 1972

Diaflo ultrafilters have been studied for the fractionation of organic matter in natural water. O... more Diaflo ultrafilters have been studied for the fractionation of organic matter in natural water. One method for their use, including pretreatment, is described. The filter retention is not only depending on the weight of the molecule but also on the charge as shown by experiments with dyestuffs and inorganic ions. For pure solutions of phosphate and nitrate the retentions were

Verhandlungen, Mar 1, 2006

Verhandlungen, Sep 1, 2005

Environmental Monitoring and Assessment, Jun 2, 2006

To abate the severe acidification of Swedish lakes are about 7% directly limed (AL-lakes). These ... more To abate the severe acidification of Swedish lakes are about 7% directly limed (AL-lakes). These are important to include when assessing acidification. Consequently, we need to estimate their chemical status as if they were not lime-affected. We hypothesize that there is a spatial dependence for calcium (Ca) and magnesium (Mg) concentrations. Spatial variation is determined using variograms. We study lakes within two 150 * 150 km quadrates (EMEP150-grid) in the middle and southern parts of Sweden. We model Ca in AL-lakes using the Ca and Mg concentrations in nearby, unaffected lakes (UL-lakes). The mean Ca/Mg for the three or seven closest UL-lakes is used. We assume that Ca/Mg is constant for UL-lakes and that Mg unaltered by liming. For UL-lakes, Ca and Mg are spatially dependent. For AL-lakes, there is a spatial dependence for Mg, but, as anticipated, not for Ca. The modeled Ca for UL-lakes show a good correspondence with measured Ca; r 2 > 0.6; slopes close to 1 and intercepts almost 0. Using three or seven nearby lakes when modeling Ca give similar results. Modeled Ca was higher than measured Ca for 36% (three closest lakes) and 38% (seven closest) of the modeled AL-lakes in the middle part of Sweden. The corresponding results for the southern part were 10% and 9%, respectively. This model is an acceptable estimator of Ca in limed lakes and for estimating critical loads and acidification status on an EMEP-scale.