USE OF FACTOR-ANALYSIS TO INVESTIGATE PROCESSES CONTROLLING THE CHEMICAL-COMPOSITION OF 4 STREAMS IN THE ADIRONDACK MOUNTAINS, NEW-YORK

Four streams were monitored intensively over a 2 year period. Factor a nalysis was used to identify interrelationships between dissolved spec ies during this period, and to determine physical processes controllin g their behaviour. Analysis of the full dataset identified species whi ch varied predominantly on an episodic timescale, and species which we re subject to seasonal cycles. Two-month subsets of data were defined to remove the influence of seasonal cycles, and factor analysis of ind ividual subsets then allowed episodic behaviour to be examined for eac h 2 month period. Results showed that base cation dilution was a consi stent cause of changes in acid neutralising capacity (ANC) in all four streams. NO3- exhibited strong seasonality in concentration and also in episode behaviour, increasing during winter-snowmelt episodes, but diluting during some summer episodes. DOC concentrations also varied s easonally, but 2 month analysis indicated episodic increases during al l periods. SO42- did not exhibit consistent episodic behaviour, as it was strongly influenced by antecedent conditions. Behaviour of Ca2+ an d Mg2+ was apparently influenced by a significant soil source in three of the streams.