High rates of benthic carbon remineralisation in the abyssal Arabian Sea

U Witte*, O Pfannkuche

*Corresponding author for this work

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

During the large-scale deep-sea programme BIGSET in situ measurements of sediment community oxygen consumption (SCOC) were carried out during three cruises between 1995-1998 at five abyssal sites (3190-4450 m water depth) in the deep Arabian Sea in order to elucidate the regional and temporal variation of benthic carbon remineralisation. SCOC ranged from 0.9-6.3 mmol O(2) m(-2) d(-1), with highest values in the western and northern Arabian Sea and lowest values in the southern Arabian Sea. For the central Arabian Sea intermediate oxygen uptake rates were detected. This regional pattern mirrors the overall regional pattern of primary productivity in surface waters and vertical particulate organic carbon (POC) flux at 1000 mab, Primary productivity in Arabian Sea surface waters and particulate flux into the deep-sea are controlled by the monsoon system and the flux maxima during the SW and NE monsoon are among the highest particle fluxes recorded in the deep open ocean. Highest flux rates were recorded in the western and northern Arabian Sea and decreased towards the central and southern Arabian Sea. SCOC at our western, northern and eastern Arabian Sea stations WAST, NAST and EAST were considerably higher than so far detected in other abyssal areas of the global oceans, and vertical POC flux can account for only 20-50% of benthic carbon remineralisation (BCR). Possible explanations for the high rates of BCR at these stations that are situated close to the continental margins are discussed: the accelerated deposition of very labile organic matter due to eolian dust particles, enhanced rain efficiencies, and lateral advection. A significant temporal variability in SCOC only could be detected at the eastern and western Arabian Sea stations WAST and EAST. (C) 2000 Elsevier Science Ltd, All rights reserved.

Original languageEnglish
Pages (from-to)2785-2804
Number of pages20
JournalDeep Sea Research Part II: Topical Studies in Oceanography
Volume47
Issue number14
Publication statusPublished - 2000

Keywords

  • COMMUNITY OXYGEN-CONSUMPTION
  • EASTERN NORTH PACIFIC
  • DEEP-SEA
  • PARTICLE-FLUX
  • SEASONAL REPRODUCTION
  • CONTINENTAL-SLOPE
  • ORGANIC-MATTER
  • OCEAN
  • PATTERNS
  • SEDIMENTATION

Cite this

High rates of benthic carbon remineralisation in the abyssal Arabian Sea. / Witte, U; Pfannkuche, O.

In: Deep Sea Research Part II: Topical Studies in Oceanography, Vol. 47, No. 14, 2000, p. 2785-2804.

Research output: Contribution to journalArticle

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AB - During the large-scale deep-sea programme BIGSET in situ measurements of sediment community oxygen consumption (SCOC) were carried out during three cruises between 1995-1998 at five abyssal sites (3190-4450 m water depth) in the deep Arabian Sea in order to elucidate the regional and temporal variation of benthic carbon remineralisation. SCOC ranged from 0.9-6.3 mmol O(2) m(-2) d(-1), with highest values in the western and northern Arabian Sea and lowest values in the southern Arabian Sea. For the central Arabian Sea intermediate oxygen uptake rates were detected. This regional pattern mirrors the overall regional pattern of primary productivity in surface waters and vertical particulate organic carbon (POC) flux at 1000 mab, Primary productivity in Arabian Sea surface waters and particulate flux into the deep-sea are controlled by the monsoon system and the flux maxima during the SW and NE monsoon are among the highest particle fluxes recorded in the deep open ocean. Highest flux rates were recorded in the western and northern Arabian Sea and decreased towards the central and southern Arabian Sea. SCOC at our western, northern and eastern Arabian Sea stations WAST, NAST and EAST were considerably higher than so far detected in other abyssal areas of the global oceans, and vertical POC flux can account for only 20-50% of benthic carbon remineralisation (BCR). Possible explanations for the high rates of BCR at these stations that are situated close to the continental margins are discussed: the accelerated deposition of very labile organic matter due to eolian dust particles, enhanced rain efficiencies, and lateral advection. A significant temporal variability in SCOC only could be detected at the eastern and western Arabian Sea stations WAST and EAST. (C) 2000 Elsevier Science Ltd, All rights reserved.

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KW - EASTERN NORTH PACIFIC

KW - DEEP-SEA

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KW - CONTINENTAL-SLOPE

KW - ORGANIC-MATTER

KW - OCEAN

KW - PATTERNS

KW - SEDIMENTATION

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JO - Deep Sea Research Part II: Topical Studies in Oceanography

JF - Deep Sea Research Part II: Topical Studies in Oceanography

SN - 0967-0645

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ER -