Acidification signals in estuarine sediment cores

• Published in: Limnology and Oceanography
• Main Author: Egeberg, Per Kristian
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1995
• Subjects: Aquatic Science; Oceanography; Norway; Atlantic salmon
• Online Access: http://dx.doi.org/10.4319/lo.1995.40.8.1438; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.4319%2Flo.1995.40.8.1438; https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1995.40.8.1438

The hypothesis that estuarine sediment cores contain signals which can be used to reconstruct shifts in the concentration of riverine humic matter (HM) and dissolved aluminum (Al) during acidification is examined. Dated sediment cores from Topdal Fjord (southern Norway) were analyzed for humic matter and alkaline extractable Al. The proportions of riverine and marine HM were estimated from carbon‐to‐nitrogen ratios (C: N). The results agree qualitatively and quantitatively with predictions based on Al and HM behavior in estuaries and the suspected effect of acidification on the concentration of these parameters. The doubling in the concentration of riverine Al and 50% reduction in riverine HM in sediment cores from the Topdal estuary coincide with an abrupt increase in the proportion of Topdal River discharge originating from areas in which the critical loads of acidity have been exceeded by sulfur deposition. HM started to decrease and Al started to increase concurrently with declining catches of Atlantic salmon around a . d . 1900.