LONGITUDINAL AQUEOUS BIOGEOCHEMISTRY OF THE LITTLE CHAZY WATERSHED, NORTHEASTERN NEW YORK

Lateral and longitudinal variations in aqueous biogeochemistry were analyzed throughout the Little Chazy watershed in Northeastern, New York focusing on headwaters draining the sandstone pavement pine barrens at Altona Flat Rock. In order to characterize the effects of hydrologic source area on surface water chemistry and to examine the influence of dissolved organic carbon on aluminum speciation, surface and groundwater samples, and bulk precipitation samples were analyzed for alkalinity, specific conductance, anions (Cl^-, SO₄^2-, NO₃^-), phosphorus (total P and dissolved reactive P), ammonium, metal cations, (Ca²⁺, Mg²⁺, K⁺, Na⁺), monomeric aluminum (organically complexed and inorganic), and DOC.

A Piper plot analysis of ion variability, in which Na⁺ + K⁺ and Ca²⁺ + Mg²⁺ were combined on a cation ternary diagram and Cl^- and NO₃^- were used for the anion ternary, distinguished samples by source area showed related groupings of samples. Precipitation, wetland, and many Flat Rock samples plotted centrally on the Piper diamond indicating even mixtures of cationic species. A stacked ion chart shows stream ion concentrations increased upon leaving Flat Rock, likely because stream courses pass residences, roadways, and agricultural areas in addition to deeper soils and changes in bedrock composition.

Principle component analysis shows a continuous progression of samples down the first principle component from Flat Rock samples downstream. The first dimension was explained by cations, alkalinity and specific conductance, and the second by aluminum species, DOC and K⁺. Flat Rock waters predominately plotted with groundwater samples, except for samples from North Flat Rock, which trended lower on the second principle component.

Dissolved organic carbon increased steadily through wetlands with simple surface (single flow path) hydrologic systems (Cold Spring Brook and Tracy Brook). Complicated hydrologic systems (Northern Flat Rock) showed random or decreasing longitudinal variation in DOC. A positive correlation of aluminum species concentration with DOC concentration was observed.