A critical limit for acid neutralizing capacity in Norwegian surface waters, based on new analyses of fish and invertebrate responses

Lien, L.; Raddum, Gunnar G.; Fjellheim, Arne; Henriksen, A.

doi:10.1016/0048-9697(95)04894-4

Cited by 104 publications

(74 citation statements)

References 7 publications

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“…4 and Table 1). Surface water ANC and pH are standard indicators used in acidification studies, as both are strongly indicative of biological recovery (Hutchinson et al, 1989;Lien et al, 1996). In addition, Table 1.…”

Section: Influence Of Emission Reductions and Climate On Recoverymentioning

confidence: 99%

The impacts of future climate change and sulphur emission reductions on acidification recovery at Plastic Lake, Ontario

Aherne

Futter

Dillon

2008

Hydrol. Earth Syst. Sci.

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Abstract. Climate-induced drought events have a significant influence on sulphate export from forested catchments in central Ontario, subsequently delaying the recovery of surface waters from acidification. In the current study, a model chain that employed a statistical downscaling model, a hydrological model and two hydrochemical models was used to forecast the chemical recovery of Plastic Lake sub-catchment 1 (PC1) from acidification under proposed deposition reductions and the A2 emission scenario of the Intergovernmental Panel on Climate Change. Any predicted recovery in stream acid neutralising capacity and pH owing to deposition reductions were clearly offset by large acid effluxes from climateinduced drought events. By 2100, ANC is predicted to show large variations ranging between 10 and −30 µmol c L −1 . Similarly, predicted pH in 2100 is lower (>0.05 of a pH unit) than the value simulated for 2000 (pH 4.35). Despite emission reductions, the future scenario paints a bleak picture of reacidification at PC1 to levels commensurate with those of the late 1970s. The principal process behind this reacidification is the oxidation of previously stored (reduced) sulphur compounds in wetlands during periods of low-flow (or drought), with subsequent efflux of sulphate upon rewetting. Simulated catchment runoff under the A2 emissions scenario predictes increased intensity and frequency of lowflow events from approximately 2030 onwards. The Integrated Catchments model for Carbon indicated that stream DOC concentrations at PC1 will also increase under the future climate scenario, with temperature being the principal driver. Despite the predicted (significant) increase in DOC, pH is not predicted to further decline (beyond the climateinduced oxidation scenario), instead pH shows greater variability throughout the simulation. As echoed by many recent studies, hydrochemical models and model frameworks need to incorporate the drivers and mechanisms (at appropriCorrespondence to: J. Aherne (julian.aherne@ucd.ie) ate time-scales) that affect the key biogeochemical processes to reliably predict the impacts of climate change.

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Section: Influence Of Emission Reductions and Climate On Recoverymentioning

confidence: 99%

The impacts of future climate change and sulphur emission reductions on acidification recovery at Plastic Lake, Ontario

Aherne

Futter

Dillon

2008

Hydrol. Earth Syst. Sci.

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“…where the surfeit of acid anions relative to base cations, tend to be balanced by elevated concentrations of acid cations (H + and Al 3+ ) and can almost invariably be considered to be acidified. The use of a critical ANC value (ANCcrit) to determine the threshold above which damage from acidification is unlikely to occur forms the basis of the acidification critical loads concept, and values ranging from 0 -50 µeq L -1 have been applied internationally, primarily to reflect risk of damage to salmonid populations (Lien et al, 1996). An ANCcrit of 20 µeq L -1 is currently recommended for UK waters (Curtis et al, 2014).…”

Section: Definition Of Reference Conditionsmentioning

confidence: 99%

A Water Framework Directive-compatible metric for assessing acidification in UK and Irish rivers using diatoms

Juggins

Kelly²,

Allott

et al. 2016

Science of The Total Environment

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Freshwater acidification continues to be a major problem affecting large areas of Europe, and while there is evidence for chemical recovery, similar evidence for biological recovery of freshwaters is sparse. The need for a methodology to identify waterbodies impacted acidification and to assess the extent of biological recovery is relevant to the EU Water Framework Directive, which requires methods to quantify differences in biology between impacted and unimpacted or reference sites. This study presents a new WFD-compliant metric based on diatoms (Diatom Acidification Metric: DAM) for assessing the acidification status of rivers. A database of 558 benthic diatom samples and associated water chemistry data was assembled. Diatom taxa were assigned to one of 5 indicator classes on the basis of their pH optimum, assessed using Gaussian logistic regression, and these indicator values used to calculate a DAM score for each site using weighted averaging. Reference sites were selected on the basis of their acid neutralising capacity (ANC) and calcium concentration, and a regression model developed to predict expected DAM for each site using pH and total organic carbon (TOC) concentration. Site-specific DAM scores were used to calculate ecological quality ratios ranging from ≥1, where the diatom assemblage showed no impact, to (theoretically) 0, when the diatom assemblage was indicative of major anthropogenic activities. The boundary between 'high' and 'good' status was defined as the 25th percentile of Ecological Quality Ratios (EQRs) of all reference sites. The boundary between 'good' and 'moderate' status was set at the point at which nutrient-sensitive and nutrient-tolerant taxa were present in equal relative abundance. The methodology was evaluated using 2 long-term data from 11 sites from the UK Uplands Waters Monitoring Network and is shown to perform well in discriminating naturally acid from acidified sites.

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“…Driscoll et al 1991). The lower ANC threshold needed to avoid damaged brown trout (Salmo trutta) populations in acidified Norwegian lakes has earlier been estimated to be 20 leq l -1 [ANC limit ], based on data from a regional study in 1986 (Lien et al 1996). It has now been suggested to modify ANC (ANC mod ) where the permanent anionic charge of organic acids is assumed to be a part of the strong acid anions (Lydersen et al 2004).…”

Section: Fish Responses To Acidificationmentioning

confidence: 99%

“…In 1995, the threshold values to avoid fish damage on basis of ANC trad and ANC mod were 67 and 48 leq l -1 , respectively, compared with 20 and 8 leq l -1 , respectively, in 1986 (cf. Lien et al 1996;Lydersen et al 2004). A higher ANC limit in 1995 was probably needed because pH was lower and inorganic Al higher at a given ANC than in the mid 1980s.…”

Section: Fish Responses To Acidificationmentioning

confidence: 99%

Ecological threshold responses in European lakes and their applicability for the Water Framework Directive (WFD) implementation: synthesis of lakes results from the REBECCA project

et al. 2008

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The objective of this synthesis is to present the key messages and draw the main conclusions from the work on lakes in the REBECCA project, pointing out their links to theoretical ecology and their applicability for the WFD implementation. Type-specific results were obtained from analyses of large pan-European datasets for phytoplankton, macrophytes, macroinvertebrates and fish, and indicators and relationships showing the impact of eutrophication or acidification on these biological elements were constructed. The thresholds identified in many of the response curves are well suited for setting ecological status class boundaries and can be applied in the intercalibration of classification systems. Good indicators for phytoplankton (chrysophytes, cyanobacteria) and macrophytes (isoetids and charaphytes) responses to eutrophication were identified, and the level of eutrophication pressure needed to reach the thresholds for these indicators was quantified. Several existing metrics developed for macrophytes had low comparability and need further harmonisation to be useful for intercalibration of classification systems. For macroinvertebrates, a number of metrics developed for rivers turned out to be less useful to describe lake responses to eutrophication and acidification, whereas other species based indicators were more

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A critical limit for acid neutralizing capacity in Norwegian surface waters, based on new analyses of fish and invertebrate responses

Cited by 104 publications

References 7 publications

The impacts of future climate change and sulphur emission reductions on acidification recovery at Plastic Lake, Ontario

The impacts of future climate change and sulphur emission reductions on acidification recovery at Plastic Lake, Ontario

A Water Framework Directive-compatible metric for assessing acidification in UK and Irish rivers using diatoms

Ecological threshold responses in European lakes and their applicability for the Water Framework Directive (WFD) implementation: synthesis of lakes results from the REBECCA project

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