DOI: 10.1002/2017JC012940
Scopus记录号: 2-s2.0-85042225276
论文题名: Hydrothermal Alteration Promotes Humic Acid Formation in Sediments: A Case Study of the Central Indian Ocean Basin
作者: Sarma N.S. ; Kiran R. ; Rama Reddy M. ; Iyer S.D. ; Peketi A. ; Borole D.V. ; Krishna M.S.
刊名: Journal of Geophysical Research: Oceans
ISSN: 21699275
出版年: 2018
卷: 123, 期: 1 起始页码: 110
结束页码: 130
语种: 英语
英文关键词: 234U/238U activity ratio
; Al/(Al + Fe + Mn) ratio
; fulvic acids
; geochemistry
; humic substances
; manganese micronodules
; Mg/Li ratio
; Sr/Ba ratio
Scopus关键词: bacterium
; carbon isotope
; dissolved organic matter
; fracture zone
; geochemistry
; humic acid
; humic substance
; hydrothermal alteration
; hydrothermal vent
; lipid
; manganese
; plate boundary
; Indian Ocean
英文摘要: Anomalously high concentrations of humic-rich dissolved organic matter (DOM) in extant submarine hydrothermal vent plumes traveled far from source are increasingly being reported. This DOM, able to mobilize trace metals (e.g., Fe2+) has been hypothesized as originating from organic matter produced by thermogenic bacteria. To eliminate a possible abiogenic origin of this DOM, study is required of well-preserved organic compounds that can be attributed to thermogenic bacteria. The Central Indian Ocean Basin (CIOB) is part of a diffuse plate boundary and an intraplate deformation zone. Coarse fraction (>63 µ) characteristics, mineralogy, magnetic susceptibility, and geochemistry were examined in sediments of a core raised close to a north-south fracture zone near the Equator. Two horizons of distinctly brown-colored sediments were shown as hydrothermally altered from their charred fragments and geochemistry (CaCO3, Corg, Ti/Al, Al/(Al + Fe + Mn), Sr/Ba, Mg/Li, Mn micronodules, Fe/Mn). We examined whether humic substances were preserved in these sediments, and if so whether their carbon isotope distribution would support their hydrothermal origin. Alkali extraction of sediments afforded humic acids (HA) in yields up to 1.2% in the brown sediments. The remaining portions of the core had nil or low concentrations of HA. The carbon of hydrothermal HA is isotopically heavier (average δ13C, ∼ −16.3‰) compared to nonhydrothermal HA (–18.1‰), suggesting that they were probably formed from organic matter that remained after elimination of lighter carbon enriched functional groups during diagenesis. The results provide compelling evidence of HA formation from lipids originating from thermogenic bacteria. © 2017. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114852
Appears in Collections: 气候减缓与适应
There are no files associated with this item.
作者单位: Marine Chemistry Laboratory, Andhra University, Visakhapatnam, India; CSIR-National Institute of Oceanography, Dona Paula, Goa, India; CSIR-National Institute of Oceanography, Regional Centre, L.B. Colony, Visakhapatnam, India
Recommended Citation:
Sarma N.S.,Kiran R.,Rama Reddy M.,et al. Hydrothermal Alteration Promotes Humic Acid Formation in Sediments: A Case Study of the Central Indian Ocean Basin[J]. Journal of Geophysical Research: Oceans,2018-01-01,123(1)