Diploptene: An indicator of terrigenous organic carbon in Washington coastal sediments
The pentacyclic triterpene 17[beta](H),21[beta](H)-hop-22(29)-ene (diploptene) occurs in sediments throughout the Columbia River drainage basin and off the southern coast of Washington state in concentrations comparable to long-chain plantwax n-alkanes. The same relationship is evident for diploptene and long-chain n-alkanes in soils from the Willamette Valley. Microorganisms indigenous to soils and soil erosion are indicated as the biological source and physical process, respectively, for diploptene in coastal sediments. Similarity between the stable carbon isotopic composition ([delta][sup 13]C[sub PDB]) of diploptene isolated from soil in the Willamette Valley (-31.2+/-0.3%) and from sediments deposited throughout the Washington coastal environment (-31.2+/-0.5%) supports this argument. Values of 6 for diploptene in river sediments are variable and 8-17[per thousand] lighter, indicating that an additional biological source such as methane-oxidizing bacteria makes a significant contribution to the diploptene record in river sediments. Selective biodegradation resulting from a difference in the physicochemical association within eroded particles can explain the absence of the more-[sup 13]C-depleted form of diploptene in Washington coastal sediments, but this mechanism remains unproven. 28 refs., 5 figs., 2 tabs.
- OSTI ID:
- 6503966
- Journal Information:
- Limnology and Oceanography; (United States), Vol. 37:6; ISSN 0024-3590
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALKANES
ECOLOGICAL CONCENTRATION
HYDROCARBONS
MICROORGANISMS
BIOLOGICAL MARKERS
SEDIMENTS
SOILS
EROSION
CARBON
COASTAL REGIONS
COLUMBIA RIVER
ENVIRONMENTAL TRANSPORT
METHANOGENIC BACTERIA
WASHINGTON
BACTERIA
DEVELOPED COUNTRIES
ELEMENTS
MASS TRANSFER
NONMETALS
NORTH AMERICA
ORGANIC COMPOUNDS
RIVERS
STREAMS
SURFACE WATERS
USA
540220* - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)
540320 - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)