DOI: 10.1016/j.gloplacha.2016.09.008
论文题名: Origin and fate of sedimentary organic matter in the northern Bay of Bengal during the last 18 ka
作者: Contreras-Rosales L.A. ; Schefuß E. ; Meyer V. ; Palamenghi L. ; Lückge A. ; Jennerjahn T.C.
刊名: Global and Planetary Change
ISSN: 0921-8181
出版年: 2016
卷: 146 起始页码: 53
结束页码: 66
语种: 英语
英文关键词: Ballast particles
; Carbon sequestration
; Eastern Bengal Slope
; Indian Summer Monsoon
; Relative sea level
Scopus关键词: Atmospheric thermodynamics
; Biogeochemistry
; Biological materials
; Budget control
; Carbon capture
; Glacial geology
; Marine biology
; Nutrients
; Organic compounds
; Productivity
; Sea level
; Sediments
; Carbon accumulation
; Carbon sequestration
; Eastern Bengal Slope
; Hemipelagic sediments
; Indian summer monsoon
; Relative sea level
; Sedimentary organic matter
; Surface productivity
; Organic carbon
英文摘要: The Northern Bay of Bengal (NBoB) is a globally important region for deep-sea organic matter (OM) deposition due to massive fluvial discharge from the Ganges-Brahmaputra-Meghna (G-B-M) rivers and moderate to high surface productivity. Previous studies have focused on carbon burial in turbiditic sediments of the Bengal Fan. However, little is known about the storage of carbon in pelagic and hemipelagic sediments of the Bay of Bengal over millennial time scales. This study presents a comprehensive history of OM origin and fate as well as a quantification of carbon sediment storage in the Eastern Bengal Slope (EBS) during the last 18 ka. Bulk organic proxies (TOC, TIC, TN, δ13CTOC, δ15NTN) and content and composition of total hydrolysable amino acids (THAA) in a sediment core (SO188-342KL) from the EBS were analyzed. Three periods of high OM accumulation were identified: the Late Glacial (LG), the Bölling/Alleröd (B/A), and the Early Holocene Climatic Optimum (EHCO). Lower eustatic sea level before 15 ka BP allowed a closer connection between the EBS and the fluvial debouch, favoring high terrestrial OM input to the core site. This connection was progressively lost between 15 and 7 ka BP as sea level rose to its present height and terrestrial OM input decreased considerably. Export and preservation of marine OM was stimulated during periods of summer monsoon intensification (B/A and EHCO) as a consequence of higher surface productivity enhanced by cyclonic-eddy nutrient pumping and fluvial nutrient delivery into the photic zone. Changes in the THAA composition indicate that the marine plankton community structure shifted from calcareous-dominated before 13 ka BP to siliceous-dominated afterwards. They also indicate that the relative proportion of marine versus terrestrial OM deposited at site 342KL was primarily driven by relative sea level and enlarged during the Holocene. The ballasting effect of lithogenic particles during periods of high coastal proximity and/or enhanced fluvial discharge promoted the export and preservation of OM. The high organic carbon accumulation rates in the EBS during the LG (18–17 ka BP) were 5-fold higher than at present and comparable to those of glacial upwelling areas. Despite the differences in sediment and OM transport and storage among the Western and Eastern sectors of the NBoB, this region remains important for global carbon sequestration during sea level low-stands. In addition, the summer monsoon was a key promotor of terrestrial and marine OM export to the deep-ocean, highlighting its relevance as regulator of the global carbon budget. © 2016 Elsevier B.V. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84988892886&doi=10.1016%2fj.gloplacha.2016.09.008&partnerID=40&md5=5bec8c09c0e3da4ec673d91e70b208d6
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/11603
Appears in Collections: 全球变化的国际研究计划 气候变化与战略
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作者单位: ZMT-Leibniz Center for Tropical Marine Ecology, Bremen, Germany
Recommended Citation:
Contreras-Rosales L.A.,Schefuß E.,Meyer V.,et al. Origin and fate of sedimentary organic matter in the northern Bay of Bengal during the last 18 ka[J]. Global and Planetary Change,2016-01-01,146.