Work

Rapid phosphorus removal promotes a sustained decrease in nitrogen in eutrophic lakes

Year: 2026

Type: article

Abstract: Excess phosphorus (P) leads to lake eutrophication, prompting interventions to reduce P availability. However, we have a limited understanding of how P availability impacts nitrogen (N), which also affects lake water quality. The in‐lake application of alum rapidly decreases P availability, presenting an opportunity to explore how P influences N availability and cycling. Analyzing 46 alum treatments, we found that total N (TN) decreased and TN:TP increased after treatment. This result is supported by case studies in other regions. The decrease in TN was positively related to the decrease in TP and the increase in clarity in shallow lakes. Decreased TN persisted despite TP increasing over 8 yr following treatment. Detailed analysis of two lakes indicated that the expansion of submerged macrophytes promoted TN removal from the water column. Our findings reveal important connections between N and P cycling and indicate that controlling P may provide additional benefits through dual‐nutrient control.

Source: Limnology and Oceanography Letters

DOI: 10.1002/lol2.70169

Authors: Catherine A. Polik, Gaston E. Small, Jacques C. Finlay

Institutions: University of Minnesota, University of St. Thomas - Minnesota

Language: English

Topic: Aquatic Ecosystems and Phytoplankton Dynamics

Subfield: Environmental Chemistry

Field: Environmental Science

Domain: Physical Sciences

SDG: Clean water and sanitation

Open Access status: gold

Estimated APC paid: $3,700