Seasonal and spatial variability of polyphosphate in the water column of Hamilton Harbour

Session: 04. - Restoring Hamilton Harbour: Tilting at Windmills or a Possible Dream?

Jiying Li, University of Toronto Scarborough, [email protected]
Arthur Zastepa, Environment and Climate Change Canada, [email protected]
Stefan Markovic, University of Toronto Scarborough, [email protected]
Susan Watson, University of Waterloo, [email protected]
Maria Dittrich, University of Toronto Scarborough, [email protected]

Abstract

Polyphosphate (polyP) has been found ubiquitously in living organisms including aquatic primary producers, and its dynamic processes (accumulation/liberation) are suggested to serve as phosphorus (P) storage strategies to survive less favorable conditions. Yet the processes of polyP metabolism has not been documented and investigated in natural aquatic environments. The role of polyP in P recycling on ecosystem scale remains unquantified. We show results of seasonal and spatial variability of polyP in particulate matters in the water column of Hamilton Harbour at two sites (nearshore vs offshore). Polyphosphate in the surface water ranged 0.063 - 0.28 umol/L nearshore and 0.068 – 0.16 umol/L offshore. 30 – 64% of polyP was contributed by small size particles of 0.2 – 2 um that likely represent picoplankton.  Strong seasonal dynamic was observed: polyP increased in the summer (July), peaked in early August and gradually declined in fall (September – November), following similar trend of primary productivity. PolyP concentrations decreased with depth, with recycling efficiencies of 30- 72% nearshore and 48 – 87% offshore. These results suggest highly dynamic polyP metabolism in plankton responding to variable environmental conditions, and the active cycling of polyP within the water column helps retaining bioavailable P to support primary productivity.

1. Keyword
Hamilton Harbour

2. Keyword
phosphorus

3. Keyword
phytoplankton

4. Additional Keyword
polyphosphate