Department of Geography

College of Liberal Arts

California State University, Long Beach

========================================

Abstracts of Conference Presentations

========================================
 

Dr. David F. Porinchu

is first author on a presentation co-authored with Glen M. MacDonald (ULCA):

"Paleoevironmental Time Series from Postglacial Lake Basins on the Kola Peninsula, Russia" to the Association of American Geographers meeting in Philadelphia, March 2004.

As part of a multi-proxy study, analysis of midge remains (Insecta: Diptera: Chironomidae) preserved in lake sediment was undertaken to assess long-term aquatic ecosystem response to climate and vegetation change at treeline on the Kola Peninsula, Russia. A total of 30 lakes were sampled to determine the contemporaneous relationship between climate and chironomid distribution in the region. Principal components analysis (PCA) of the environmental data indicates that three broad groups of lakes can be identified based on vegetation zones and limnological data. Tundra lakes tend to be deep and oligotrophic (high secchi values, low total organic carbon), whereas forested lakes, which are found at higher elevations, are more productive and have higher surface water temperatures. Lakes found in the transition zone between forest and tundra, are dispersed more widely in the ordination, suggesting higher inter-lake variability. Canonical correspondence analysis (CCA) indicates that four environmental variables, depth, secchi depth, total organic carbon and Si, are highly correlated with the distribution of chironomids along the transect. A chironomid-temperature inference model, based on a larger regional calibration set, was developed and applied to two Holocene long cores in order to reconstruct long term climate change. Results of the down-core reconstructions and implications for the understanding of post-glacial environmental and vegetation change in the region will be discussed.

========================================

[ Geography ] [ Research ] [ Liberal Arts ] [ CSULB ]
========================================

This document is maintained by Geography Webmaster: rodrigue@csulb.edu
Last revised: 01/02/04
========================================