IAGLR 2018

Phosphorus forms in suspended particulate matter in tributaries of the Bay of Quinte

Stefan Markovic, University of Toronto Scarborough, [email protected]
Jiying Li, University of Toronto Scarborough, [email protected]
Jay Guo, ECCC-ECCC Environment and Climate Change Canada, [email protected]
Felix Ouellet, ECCC-ECCC Environment and Climate Change Canada, [email protected]
Jorge Hurtado, ECCC-ECCC Environment and Climate Change Canada, [email protected]
Shan Mugalingam, Lower Trent Conservation, [email protected]
Agnes Richards, Environment Canada, [email protected]
Maria Dittrich, University of Toronto Scarborough, [email protected]

Abstract

While phosphorus (P) is widely recognized as the limiting nutrient in freshwater aquatic environments, it is unclear to what extent riverine delivery of particulate P drives algal blooms. Since P sources under different hydrological regimes are highly dynamic, the bioavailability of riverine P often varies between periods of low and high flow. However, suspended particulate P forms and cycling mechanisms are often not well understood. This is significant omission because non-point particulate P loading is the key factor contributing to eutrophication in many lakes. Here we present forms and bioavailability of suspended particulate P from predominantly agricultural catchments of Napanee river and Wilton Creek, tributaries of the Bay of Quinte (Lake Ontario). We show that redox sensitive and organic P binding forms dominate in suspended riverine particulate matter which is mostly made of aggregations of organic matter, diatom shells and to a lesser extent material sourced from bedrock - clays, quartz and carbonates. Mineral assemblage and P binding forms point to surface soil and resuspended riverbed sediments as the dominant source of particulate P. These results improve understanding of particulate P dynamics and have important implications for P control measures in the Bay of Quinte.

1. Keyword
phosphorus

2. Keyword
sediment load

3. Keyword
watersheds