Linking sediment geochemistry with catchment processes, internal phosphorus loading and lake water quality

Area of Science:

• Environmental Science
• Geochemistry
• Limnology

Background:

• Lake water quality is influenced by catchment land use and internal phosphorus loading, but data is limited.
• Sediment geochemistry plays a crucial role in phosphorus cycling and regeneration within lakes.

Purpose of the Study:

• Investigate factors affecting sediment geochemistry variations.
• Assess diagenetic impacts on phosphorus regeneration.
• Determine the role of sediment phosphorus forms in internal loading.
• Evaluate the effect of internal loading on lake water quality.

Main Methods:

• Analyzed a comprehensive dataset from 27 southern Finland lakes.
• Examined sediment geochemistry, vertical profiles, and phosphorus fractions.
• Utilized statistical modeling to link land use, sediment properties, and water quality.

Main Results:

• Sediment iron-bound phosphorus (Fe-P) increased with field and populated area percentages.
• Internal phosphorus loading was positively related to sediment Fe-P and organic P (Org-P).
• Diagenetic transformations influence long-term phosphorus release, especially in deeper lakes.

Conclusions:

• Reducing phosphorus inputs from fields and populated areas decreases internal loading and improves lake water quality.
• Sediment Fe-P is a key factor linking land use to internal phosphorus loading and water quality degradation.