December 7, 2018
Web Feature

Eroding Gaps in Understanding the Global Carbon Cycle

A new process-based model represents global changes in sediment and particulate organic carbon levels due to soil erosion, an important missing piece in Earth system models

Snow melt and erosion

Soil erosion models evaluate the process of sediment and particulate organic carbon and nutrients detaching from the soil matrix by rainfall and runoff, ultimately entering rivers that carry them to coastal zones and oceans.

The Science

Around the world, sediment left behind from soil erosion leads to environmental impacts such as reduced organic nutrients in the soil, degraded water quality, and increased flooding. However, the impacts of sediment yield on the global carbon cycle remain largely uncertain. This is because, until now, computer models that simulated Earth systems lacked a way to represent soil erosion processes. In a recent study led by scientists at the U.S. Department of Energy's Pacific Northwest National Laboratory, researchers developed a new process-based model that can represent detailed variations in sediment, organic carbon, and nutrient yields across space and time in Earth system models.

The Impact

The input of organic carbon from land to oceans through river transport is a key component in the global carbon cycle. Increasing observational evidence suggests that land-based carbon is biogeochemically modified on its journey to the oceans. A large fraction of this altered carbon comes from soil erosion. With the new process-based model of sediment and particulate organic carbon yields, Earth system models can better simulate erosion-induced organic carbon and nutrient fluxes and how they may change in the future.

 

Reference: Z. Tan, L.R. Leung, H.-Y. Li, T. Tesfa, "Modeling sediment yield in land surface and Earth system models: Model comparison, development and evaluation." Journal of Advances in Modeling Earth Systems 10 in press (2018). [DOI: 10.1029/2017MS001270].

Published: December 7, 2018

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