An Assessment of the potential impact of the Gothenburg Protocol on surface water chemistry using the dynamic MAGIC model at acid sensitive sites in the UK

Over the past two decades, substantial reductions in the deposition of acidifying substances (primarily sulphur) have occurred in most parts of Europe and, following recent agreements, this trend is likely to continue. The question arises as to how have sensitive ecosystems reacted, and will react in the future, to these reduced inputs of acidity? In this paper, the SMART dynamic acidification model predicts the possible recovery of 36 acid-sensitive Finnish headwater lakes, for which both catchment soil and water quality measurements were available. The model was calibrated to measurements by adjusting poorly known parameters; it was then used to simulate soil and water chemistry until 2030 under the current legislation scenario resulting from implementing current European emission reduction agreements. Whereas most of the catchment soils show very little change in base saturation, the positive trends in lake ANC and the negative trends in lake sulphate concentrations, observed over the past decade, continue into the future, albeit at a slower pace. The model predicts that, during 201030, all lakes will have reached a positive ANC, a pre-requisite for the recovery of fish populations.

“…6) indicating the greatest sensitivity to acidic inputs. This is consistent with model results from acidsensitive sites in the UK (Jenkins and Cullen, 2001 (Fig. 6).…”

Section: Resultssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Modelling the recovery of acid-sensitive Finnish headwater lakes under present emission reduction agreements

Posch¹,

Forsius

Johansson

et al. 2003

“…A first application to several experimentally manipulated catchments Jenkins and Cullen, 2001) suggests that MAGIC7 will continue to function as a robust and reliable tool for both scientific and assessment activities.…”

Section: Nitrogen Immobilisation Equationsmentioning

confidence: 99%

Modelling the effects of acid deposition: refinements, adjustments and inclusion of nitrogen dynamics in the MAGIC model

Cosby

Ferrier²,

Jenkins

et al. 2001

Self Cite

247

196

The MAGIC model of the responses of catchments to acidic deposition has been applied and tested extensively over a 15 year period at many sites and in many regions around the world. Overall, the model has proven to be robust, reliable and useful in a variety of scientific and managerial activities. Over the years, several refinements and additions to MAGIC have been proposed and/or implemented for particular applications. These adjustments to the model structure have all been included in a new version of the model (MAGIC7). The log aluminium -pH relationship now does not have to be fixed to aluminium trihydroxide solubility. Buffering by organic acids using a triprotic analog is now included. Dynamics of nitrogen retention and loss in catchments can now be linked to soil nitrogen and carbon pools. Simulation of short-term episodic response by mixing fractions of different water types is also possible. This paper presents a review of the conceptual structure of MAGIC7 relating to long-term simulation of acidification and recovery, describes the conceptual basis of the new nitrogen dynamics and provides a comprehensive update of the equations, variables, parameters and inputs for the model.

“…Computer predictions for the future were made using realistic scenarios, e.g. under the Gothenburg Protocol (Wright, 2001;Jenkins and Cullen, 2001;Jenkins et al, 2003). In this paper, the influence of the contrasting geochemistries of two catchments was tested by computer simulations of long-term chemical changes.…”

Section: Introductionmentioning

confidence: 99%

Modelling long-term changes in stream water and soil chemistry in catchments with contrasting vulnerability to acidification (Lysina and Pluhuv Bor, Czech Republic)

Hruška

Krám

2003

In two Czech catchments covered by Norway spruce forests, the MAGIC model was used to simulate annual stream water and soil chemistry for the period 18512030. These two sites represent geochemical end-members of ecosystem sensitivity to acidification (acid-sensitive granitic Lysina catchment vs. acid-resistant serpentinitic Pluhuv Bor catchment). Although the total deposition of sulphur to the catchments declined by 75% between 1990 and 2002, the recovery of stream water pH was relatively small over this period. At Lysina, the annual discharge-weighted mean pH of stream water increased only from 3.92 to 4.01, although SO 4 concentration declined very sharply from 570 meq L 1 in 1990 to 150 meq L 1 in 2002. Stream water buffering was caused mainly by dissociation of organic acids. At Pluhuv Bor, the annual mean pH varied inversely with the annual discharge. Stream water concentrations of SO 4 declined dramatically at Pluhuv Bor, from 1040 meq L 1 in 1992 to 220 meq L 1 in 2002. Using atmospheric deposition as specified in the Gothenburg Protocol, the model predicts that, at Lysina, stream water pH will increase to 4.3 and soil base saturation will increase to 6.0% by 2030 (from 5.6% in 2002); corresponding pre-industrial stream water pH was simulated to be 5.5 and soil base saturation to be 25%. At Pluhuv Bor, the pre-industrial pH was estimated to be 7.2 and the corresponding base saturation was 94%. Large anthropogenic acidification in the 20 th century caused only a small decline in pH (to 6.9) and base saturation (to 88%). Simulations in accordance with the Gothenburg Protocol predict that the pH should increase by 0.2 pH units and the base saturation by 1% by 2030. Under this protocol, critical loads of atmospheric deposition for SO 4 and NO 3 will not be exceeded at Pluhuv Bor but will be exceeded at Lysina.