Data from National Ecological Observatory Network (NEON) Helps Unlock the Role of Deep Soil in Carbon Storage
A new study published in Nature Climate Change, authored by Dr. Marc G. Kramer and Dr. Oliver A. Chadwick, examines the role of reactive minerals in supporting carbon sequestration in soil. "Climate-Driven Thresholds in Reactive Mineral Retention of Soil Carbon at the Global Scale," quantified how much carbon is bound with reactive minerals in soil from different ecosystems around the world. Their analysis used soil samples from 47 NEON field sites in addition to a global soil data set from North America , Indonesia, Europe, Central America and South America. The results suggest that reactive minerals in deep soils play a much bigger role in global carbon sequestration than has previously been realized.
An estimated 600 megatons of carbon is currently held by reactive minerals in soils around the world—more than twice the amount of carbon that humans have added to the atmosphere since the Industrial Revolution began. Understanding the pathways and variables that influence carbon sequestration in soil could lead to new ideas to combat climate change and protect vulnerable ecosystems.
The new study quantified how carbon bound with reactive minerals changes across different climate zones. The researchers wanted to shed light on the role climate plays in reactive minerals storage in soils in ecosystems around the world.
"This is one of the most important pathways for long-term carbon retention, but it hasn't been extensively studied at the global scale in relation to climate,” Kramer said. “We wanted to look at a global scale to get a better understanding of the links between rainfall, reactive mineral carbon storage, and how shifts in climate patterns may change this pathway in the future."
Comparing different ecosystems, Kramer saw that moist environments sequestered far more carbon than dry ones. In desert climates, where rain is scarce and water easily evaporates, reactive minerals retain less than 6 percent of the soil’s organic carbon. Dry forests are not much better. But wet forests can have as much as half their total carbon bound up by reactive minerals.
Kramer and Chadwick used soil samples from the NEON project because they span climate zones across all of North America, including deserts, grassland, dry forest, wet forest and tundra areas. NEON collects physical soil samples from each of the terrestrial field sites for biogeochemical, physical and organismal analysis. Archival samples are available to outside researchers who need physical samples to conduct their own analysis. This study used samples collected from "megapits" dug up to 2m deep during the construction of each terrestrial NEON field site, providing a comprehensive set of samples of known provenance collected from each of the 20 North American ecoclimatic NEON domains. The team combined these data with a global soils data set which included samples from North America, New Caledonia, Indonesia, Europe, Central America and Brazil.
The NEON program produces a wide range of open access data and archival samples that can be used to solve key questions in research studies of carbon sequestration and climate. In addition to soil samples, a wide variety of meteorological measurements are collected at NEON field sites, including temperature, humidity, precipitation, and fluxes of carbon, water, and energy between terrestrial ecosystems and the atmosphere. NEON also collects measurements of soil moisture, soil CO2 and temperature as well as organismal field sampling data to better understand how our ecosystems are changing over time.
“As NEON nears completion of the construction phase and moves into full operation, more and more data will become available for use by researchers across a wide range of disciplines fulfilling the goals of this important, unprecedented initiative by the NSF in partnership with Battelle,” said Gene Kelly, Chief Scientist and Observatory Director.
The NEON program, managed by Battelle for the National Science Foundation, is a continental-scale ecological observation facility that collects and provides open data from 81 field sites across the United States that characterize and quantify how our nation's ecosystems are changing. The data will contribute to a better understanding and more accurate forecasting of how human activities impact ecosystems and how society can more effectively address critical ecological questions and issues. The data is available for any researcher to use. Learn more at neonscience.org.
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