High-resolution diatom delta O-18 records, from the last 150 years, reflecting changes in amount of winter precipitation in two sub-Arctic high-altitude lakes in the Swedish Scandes
2010 (English)In: Journal of Quaternary Science, ISSN 0267-8179, E-ISSN 1099-1417, Vol. 25, no 6, 918-930 p.Article in journal (Refereed) Published
Waters from high-altitude alpine lakes are mainly recharged by meteoric water. Because of seasonal variations in precipitation and temperature and relatively short hydraulic residence times, most high-altitude lakes have lake water isotopic compositions (delta O-18(lake)) that fluctuate due to seasonality in water balance processes. Input from snowmelt, in particular, has a significant role in determining lake water delta O-18. Here we compare two high-resolution delta O-18(diatom) records from lake sediments in the Swedish Scandes with instrumental data from the last century obtained from nearby meteorological stations. The time period AD 1900-1990 is characterised by an increase in winter precipitation and high winter/summer precipitation ratios and this is recorded in delta O-18(diatom) as decreasing trends. Lowest delta O-18(diatom) values and highest amount of winter precipitation are found around AD 1990 when the winter North Atlantic Oscillation index was above +2. We conclude that for the last 150 a the main factor affecting the delta O-18(diatom) signal in these sub-Arctic high-altitude lakes with short residence times has been changes in amount of winter precipitation and that delta O-18(diatom) derived from high-altitude lakes in the Swedish Scandes can be used as a winter precipitation proxy.
Place, publisher, year, edition, pages
2010. Vol. 25, no 6, 918-930 p.
oxygen isotopes, high-altitude lakes, diatom silica, winter precipitation, North Atlantic Oscillation
IdentifiersURN: urn:nbn:se:su:diva-51755DOI: 10.1002/jqs.1372ISI: 000281858800010OAI: oai:DiVA.org:su-51755DiVA: diva2:386017
authorCount :72011-01-122011-01-122011-01-12Bibliographically approved