This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kdster, D. Articles by Pienitz, R. Search for Related Content GeoRef GeoRef Citation Social Bookmarking                   What's this?

Late-Holocene environmental history of two New England ponds: natural dynamics versus human impacts

Paleolimnology Paleoecology Laboratory, Centre d'etudes nordiques and Department of Geography, Universite' Laval, Quefbec, Quebec GIK 7P4, Canada; Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada dkoster{at}sciborg.uwaterloo.ca

Reinhard Pienitz

Department of Biology, University of Waterloo, 200 University Avenue W, Waterloo, Ontario N2L 3GI, Canada

Analyses of sedimentary diatoms in two New England ponds reveal limnological changes during the past 2500 years that are related to climatic change, anthropogenic activities and natural disturbance. Deforestation in the lake catchments during the eighteenth and nineteenth centuries temporarily affected diatom assemblages, with subsequent recovery. However, algal communities did not return completely to presettlement conditions as a result of long-term trends in climatic change, small-scale natural disturbances and delayed watershed recovery from acidification. A short-term rise in diatominferred dissolved organic carbon (DOC) in Levi Pond was related to partial removal of vegetation by logging in the catchment, and a similar DOC increase at North Round Pond is correlated with a hurricane and increased aquatic productivity. At Levi Pond, increasing diatom-inferred DOC concentrations during the past c. 2000 years likely reflect a long-term increase in allochthonous organic matter and peat development in the watershed related to moister conditions, supported by corresponding patterns in the stable-isotope, chironomid and pollen records. These results correspond with moisture patterns in adjacent areas inferred from pollen and sediment analyses, suggesting that diatoms in Levi Pond recorded a larger regional trend in increasing moisture. This is the first study in a temperate region that links diatom-inferred DOC concentration to past changes in moisture balance, suggesting that fossil diatoms may be a promising proxy for future palaeohydrological studies in temperate regions. However, more studies are necessary to separate the effects of peatland growth and allochthonous organic-matter input on lake-DOC concentrations.

Key Words: Palaeolimnology • diatoms • forest disturbance • dissolved organic carbon • moisture • New England • late Holocene

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?