Data from a sequential selective dissolution method to quantify storage and stability of organic carbon associated with Al and Fe hydroxide phases
type: Dataset
description: Stabilization of SOM (soil organic matter) is regulated in part by sorption and desorption reactions happening at mineral surfaces, as well as precipitation and dissolution of organo-metal complexes. Fe and Al hydroxides play a particularly significant role in SOM stabilization in soils due to their ubiquitous distribution and their highly reactive surface properties. Iron and Al hydroxides exist in soils across a wide spectrum of crystallinity, ranging from dissolved Fe and Al cations which combine with organics to form organo-metal precipitates to the more crystalline end members, goethite and gibbsite, which sorb SOM through a variety of molecular interactions. Though the importance of these sorption and precipitation reactions has long been recognized, the distribution of SOM among Fe and Al hydroxides of differing crystallinity has not been well quantified, nor has the timescale over which these stabilization mechanisms operate. In an attempt to measure the distribution of organic C among (i) Al- and Fe-humus complexes (ii) short-range-order (SRO) Al and Fe hydroxide surfaces and (iii) crystalline Fe oxyhydroxide surfaces, a single method combining several selective mineral dissolutions was applied to soils of four different geneses (a tropical forest Andisol, a temperate forest basaltic Mollisol, a Mediterranean coastal prairie Mollisol, and a northern mixed hardwood forest Spodosol). The traditional re- actants used in selective dissolutions were replaced with carbon-free analogues so that the carbon released along with the Fe and Al at each stage of the selective dissolution process could be measured. Selective dissolutions were performed sequentially: Na-pyrophosphate (organo-Al and Fe complexes) followed by hydroxylamine (SRO Al and Fe hydroxides) followed by dithionite-HCl (crystalline Fe hydroxides). Carbon, Al, and Fe concentrations, as well as radiocarbon abundance were measured in the solutions yielded by each stage of the selective dis- solution proc…
keyword: amerigeo
keyword: amerigeoss
keyword: arizona
keyword: california
keyword: carbon
keyword: ckan
keyword: flagstaff
keyword: geo
keyword: geoscientificinformation
keyword: geoss
keyword: hawaii
keyword: metal-hydroxides
keyword: michigan
keyword: mineral-extractions
keyword: national
keyword: north-america
keyword: radiocarbon
keyword: santa-cruz
keyword: soil
keyword: united-states
keyword: usgs-5f05171482ce21d4c3f89e67
issued: 2025-11-21T10:27:45.367874
modified: 20200824
theme: {geospatial}
contact point: Organization
  fn: Corey R. Lawrence
spatial: Location

US Migrating
type: Agent

Original Metadata
type: Distribution
description: The metadata original format
media type: text/xml
format: XML
access URL: https://data.usgs.gov/datacatalog/metadata/USGS.5f05171482ce21d4c3f89e67.xml
issued: 2022-07-28T19:59:38.776692
modified: 2025-11-21T10:27:45.354853

Digital Data
type: Distribution
description: Landing page for access to the data
media type: application/http
format: XML
access URL: https://doi.org/10.5066/P9UGPZ0R
issued: 2022-07-28T19:59:38.776701
modified: 2025-11-21T10:27:45.355276