Chemical and isotopic evidence for the in situ origin of marine humic substances
Humic and fulvic acids were extracted from marine and nonmarine Recent sediments and from soils. These acids are shown to be major components of the organic matter from marine and nonmarine sediments--some marine sediments may contain 70% of their organic carbon in the humic and fulvic acid fraction. Marine and terrestrial humic acids have similar carbon and hydrogen content, but the former generally contain more sulfur and nitrogen. delta/sup 34/S values of marine humic acid indicate that the sulfur is introduced into the organic matter as hydrogen sulfide produced by sulfate reduction. Marine humates have a rather constant delta/sup 13/C value of -20 to -22%, whereas the delta/sup 13/C of soil humic acid is related to its plant source material and usually ranges around -25 to -26%. The evidence shows that marine humic acids can be formed in situ from degradation products of plankton and are not necessarily transported from the continent. The suggested pathway of marine humic acid formation and transformation in the sediment is (1) degraded cellular material..-->..(2) water-soluble complex containing amino acids and carbohydrates..-->..(3) fulvic acids..-->..(4) humic acids..-->..(5) kerogen.
- DOE Contract Number:
- AT(04-3)-34
- OSTI ID:
- 6504190
- Journal Information:
- Limnol. Oceanogr.; (United States), Journal Name: Limnol. Oceanogr.; (United States) Vol. 17:4; ISSN LIOCA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Aquatic-- Basic Studies-- (-1989)
54 ENVIRONMENTAL SCIENCES
AQUATIC ECOSYSTEMS
AQUATIC ORGANISMS
CARBON 13
CARBON ISOTOPES
CHEMICAL COMPOSITION
CHEMISTRY
COMPARATIVE EVALUATIONS
ECOSYSTEMS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FULVIC ACIDS
HUMIC ACIDS
HUMUS
HYDROGEN COMPOUNDS
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PLANKTON
SAMPLING
SEAWATER
SEDIMENTS
SOILS
STABLE ISOTOPES
SULFUR 34
SULFUR ISOTOPES
WATER
WATER CHEMISTRY