PREDICTING RECOVERY IN ACIDIFIED FRESHWATERS BY THE YEAR 2010, AND BEYOND

Contract EVK1-1999-00087 - RECOVER:2010

Part of the 'Sustainable Management and Quality of Water'

Ecosystem Functioning

Directorate General Research

The James Hutton Institute

This page is no longer updated. The Macaulay Land Use Research Institute joined forces with SCRI on 1 April 2011 to create The James Hutton Institute.

Please visit the James Hutton Institute website.

With new funding from RESAS as part of the Strategic Science Programme (2011-2016), long term projections of surface water acidification made to the year 2010 as part of the RECOVER:2010 were compared to observed chemistry.

In 1999, as part of the EU RECOVER:2010 project, the MAGIC (Model of Acidification of Groundwater In Catchments) model was used to project acidification of acid-sensitive European surface waters in the year 2010, given implementation of the Gothenburg Protocol to the Convention on Long-Range Transboundary Air Pollution (LRTAP). A total of 202 sites in 10 regions in Europe were studied.

With new funding from RESAS, staff in the Managing Catchments and Coast group of the James Hutton Insitute compared the forecasts made during the RECOVER:2010 project with measurements for the year 2010, to give a “ground truth” evaluation of the model. To find out more about this study click here to access the paper published in Environmental Science and Technology.

Bavaria, Germany

The NE-Bavaria Mountains (Germany) are characterized by low mean annual temperatures (5-6.5°C) and high precipitation (950-1050 mm). The Lehstenbach catchment is typical of the area, with soil developed from deeply weathered granitic bedrock, which are very acid with pH(CaCl₂) < 4 and have a low base saturation (< 10% in the upper soil). The reduction in sulphate deposition from the year 1985 to 1993 was 35%. In contrast to the significant decrease in sulphate deposition in the catchment, sulphate in runoff shows only a very slight decrease up to the year 1998. Due to soil texture, low pH values and the depth of the weathered substrata soils have high sulphate storage capacities. The huge amounts of sulphate stored in the soils of the catchment act as a buffer mechanism which delays reversibility of surface water acidification by decades (Alewell 1995; Alewell et al., 1997, Manderscheid et al., 1999a,b). The Lehstenbach catchment is typical for the mountainous regions of Germany. Delay of reversibility of soil and water acidification due to release of previously stored sulphate has been reported for the Solling, the Harz as well as the Ore mountains (Erkenberg, 1991; Meiwes et al., 1994, Malessa 1995, Alewell, 1995; Alewell, 1998; Alewell et al., 1997).

Reversibility of soil acidification in catchments of deeply weathered soils

Site description Lehstenbach catchment

Location	Fichtelgebirge mountain range, NE-Bavaria, Germany; (50N, 11E)
Altitude	700-877 m.a.s.l.
Annual temperature	5 - 6.5 ºC
Annual Precipitation	950-1050 mm
Size	4.2 km²
Stock	90 % spruce (Picea abies (L.) karst.)
Bedrock	Deeply weathered granite, partly covered by solifluction layers
Soils	Mosaic of cambisols to cambic podzols
Texture	Loamy sand to loam
Soil pH	pH(CaCl₂)<4

Deposition with throughfall in kg S ha^-1 yr^-1

1998	SO₄^2-	15.0
	NO₃^-	12.4
	NH₄⁺	9.4
	H⁺	0.6

SO₄^2- Reduction	1985-1992	35%
SO₄^2- Reduction	1985-1998	69%

Average sulphate contents and estimated sulphate storage in soils and the weathered substrata of the Lehstenbach watershed, Germany.

	Sulphate content (µmol g^-1)				Sulphate storage (kg S ha^-1)
	H₂O Extractable		Na₂HPO₄ Extractable		H^_₂O Extractable		Na₂HPO₄ Extractable
	Average	SD	Average	SD	Average	SD	Average	SD
B-horizons (<0.5 m depth)*	1.19	0.93	2.28	2.33	250	186	474	483
Weathered substrata# (0.5-10m depth)	0.64	0.53	1.14	1.28	1600	1344	2800	2304

* from Jungnickel (1996), # from Schweisser (1998)

n=53 for B-horizons, n=44 for weathered substrata, SD=standard deviation

To view data from the Lehstenbach catchment and photographs of forest dieback CLICK HERE

Results from Germany

For more information contact: Christine.Alewell@bitoek.uni-bayreuth.de

REGIONS

REFERENCES

PREDICTING RECOVERY IN ACIDIFIED FRESHWATERS BY THE YEAR 2010, AND BEYOND

The James Hutton Institute

THE REGIONS

RESULTS

Bavaria, Germany

Reversibility of soil acidification in catchments of deeply weathered soils

Average sulphate contents and estimated sulphate storage in soils and the weathered substrata of the Lehstenbach watershed, Germany.