Does control of soil erosion inhibit aquatic eutrophication?
Petri Ekholm1, Jouni Lehtoranta
1Finnish Environment Institute, P.O. Box 140, FI-00251 Helsinki, Finland.
Journal of Environmental Management
|November 8, 2011
Summary
Soil erosion transports phosphorus (P) and iron oxides to water bodies. Eroded soil rich in iron oxides can influence nutrient cycling, potentially mitigating eutrophication by affecting sediment P retention.
Area of Science:
- Environmental Science
- Aquatic Chemistry
- Microbiology
Background:
- Soil erosion is a major pathway for phosphorus (P) transport to aquatic ecosystems, contributing to eutrophication.
- Current research primarily quantifies P desorption from soil particles, neglecting the role of associated soil components.
- The coupled cycling of carbon (C), iron (Fe), sulfur (S), and P in sediments, influenced by microbial processes, is critical for understanding eutrophication.
Purpose of the Study:
- To investigate the impact of iron oxides transported by eroded soil on benthic biogeochemical cycling.
- To explore how eroded soil affects microbial processes, specifically sulfate reduction, and phosphorus retention in sediments.
- To re-evaluate the role of soil erosion in eutrophication by considering sediment processes.
Main Methods:
- Literature review and synthesis of existing research on soil erosion, eutrophication, and aquatic biogeochemistry.
- Conceptual modeling of nutrient cycling pathways involving eroded soil components.
- Analysis of microbial processes, including anaerobic mineralization and sulfate reduction, in relation to iron and phosphorus dynamics.
Main Results:
- Eroded soil introduces iron oxides into aquatic sediments, influencing the cycling of C, Fe, S, and P.
- In sulfate-rich environments, iron oxides from eroded soil may promote iron cycling and inhibit microbial sulfate reduction.
- These processes can enhance the sediment's capacity to retain phosphorus, potentially counteracting eutrophication.
Conclusions:
- Soil erosion's impact on eutrophication extends beyond P loading to include alterations in sediment biogeochemistry.
- Eroded soil, particularly its iron oxide content, can play a significant role in regulating nutrient cycling and P retention in aquatic systems.
- Understanding these sediment-based processes is crucial for effective soil erosion control and eutrophication management.
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