Related Experiment Video
Updated: Jun 22, 2026

Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading
Published on: March 6, 2014
Using oxygen isotopes of phosphate to trace phosphorus sources and cycling in Lake Erie
Katy E Elsbury1, Adina Paytan, Nathaniel E Ostrom
1Earth and Planetary Sciences, University of California, Santa Cruz, Santa Cruz, California 95064, USA.
Abstract:
Water samples collected during three sampling trips to Lake Erie displayed oxygen isotopic values of dissolved phosphate (delta18Op) that were largely out of equilibrium with ambient conditions, indicating that source signatures may be discerned. delta18Op, values in the Lake ranged from +10% per hundred to +17% per hundred, whereas the equilibrium value was expected to be around +14% per hundred. The riverine weighted average delta18Op, value was +11% per hundred and may represent one source of phosphate to the Lake. The lake delta18Op, values indicated that there must be one or more as yet uncharacterized source(s) of phosphate with a high delta18Op value. Potential sources other than rivers are not yet well-characterized with respectto delta18Op of phosphate, but we speculate that a likely source may be the release of phosphate from sediments under reducing conditions created during anoxic events in the hypolimnion of the central basin of Lake Erie. Identifying potential phosphorus sources to the Lake is vital for designing effective management plans for reducing nutrient inputs and associated eutrophication.
Related Concept Videos
The Phosphorus Cycle
What are Biogeochemical Cycles?
Freshwater Microbial Ecology

