VARIATIONS IN PHOSPHORUS FRACTIONATION IN STREAM SEDIMENTS OF THE BLACK RIVER, NY

Phosphorus is a key nutrient for all organisms’ metabolic processes, and is one of many important components of aquatic systems. An overabundance can cause severe impairments in hydrologic systems. Phosphorus fractions in sediment can be influenced by a variety of factors due to the relationships between different portions of a system, such as water and soils. The Black River watershed, located in upstate New York, is a sparsely populated area with predominantly forested and agricultural land cover. This area is of particular interest because of its wide range of bedrock geologies. The headwaters are situated in crystalline/metamorphic bedrock, and the main branch of the river flows through carbonates to empty into Lake Ontario. We investigated relative changes in the distribution of phosphorus between major fractions along the axis of the river from headwaters to mouth. The most notable trends appear to be the wide range in the organic matter associated P (Org-P) concentrations and an increase in Ca associated P (Ca-P) along the river transect. In one branch of the river, Org-P was found to range in concentration from 10.6 to 28.6 mg /kg in the sediment, but no apparent trend was found. Ca-P was found to range from 10.1 to 52.5 mg/kg. Ca-P shows a slight trend as you move downstream, but the trend is impacted by tributaries entering the main branch. Ongoing studies are investigating the larger Black Creek watershed to assess the further role of bedrock type on P fractionation patterns.