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- Title
Whole-catchment liming at Tjonnstrond, Norway: an 11-year record
- Authors
Frogner, T.; Lande, A.; Kleiven, E.; Traaen, T. S.; Wright, R. F.; Hindar, A.
- Abstract
In June 1983 a whole-catchment liming experiment was conducted at Tjonnstrond, southernmost Norway, to test the utility of terrestrial liming as a technique to restore fish populations in remote lakes with short water-retention times. Tjonnstrond consists of 2 small ponds of3.0 and 1.5 ha in area which drain a 25-ha catchment. The area is located at about 650--700 meters above sea-level in sparse and unproductive forests of spruce, pine and birch with abundant peatlands. A dose of 3 ton/ha of powdered limestone were spread by helicopter to the terrestrial area. No limestone was added to the ponds themselves. Theponds were subsequently stocked with brown and brook trout. Liming caused large and immediate changes in surface water chemistry; pH increased from 4.5 to 7.0, Ca increased from 40 to 200 mu eq/L, ANC increased from -30 to +70 mu eq/L, and reactive-Al decreased from about 10to 3 mu mol/L. During the subsequent 11 years the chemical composition of runoff has decreased gradually back towards the acidic pre-treatment situation. The major trends in concentrations of runoff Ca, ANC, pH, Al and NO{sub}3{end} in runoff are all well simulated by the acidification model MAGIC. Neither the measured data nor the MAGIC simulations indicate significant changes in any other major ion as a result of liming. The soils at Tjonnstrond in 1992 contained significantly higher amounts of exchangeable Ca relative to those at the untreated reference catchment Storgama. In 1992 about 75% of the added Ca remains in the soil as exchangeable Ca, 15% has been lost in runoff, and10% is unaccounted for. The whole-catchment liming experiment at Tjonnstrond clearly demonstrates that this liming technique produces a long-term stable and favourable water quality for fish. Brown trout inboth ponds in 1994 have good condition, factors, which indicate thatthe fish are not stressed by marginal water quality due to re-acidification. The water quality is still adequate after 11 years and >20 water r
- Subjects
LAKES
- Publication
Water, Air & Soil Pollution, 1997, Vol 94, Issue 1-2, p163
- ISSN
0049-6979
- Publication type
Article