Luo, Min, Gieskes, Joris, Chen, Linying, Scholten, Jan, Pan, Binbin, Lin, Gang and Chen, Duofu (2019) Sources, degradation, and transfer of organic matter in the New Britain Shelf‐Trench continuum, Papua New Guinea. Journal of Geophysical Research: Biogeosciences, 124 . DOI 10.1029/2018JG004691.

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Abstract

Hadal trenches are considered as depocenters for organic matter and hotspots for microbial diagenetic activity. Here, we explore the sources, degradation, and transport of organic matter in the shelf‐trench continuum using seven short sediment cores collected along two transects with water depths ranging between 1,553 and 8,901 m in the New Britain Trench area, Papua New Guinea. Carbon isotopic compositions (δ13C) and radiocarbon contents (Δ14C) of sedimentary organic matter accompanied by total organic carbon/total nitrogen ratios suggest an important contribution from the preaged soil organic matter mixed by the marine algae and terrigenous C3 vascular plants. In addition, the trench axis sites are characterized by elevated accumulation of terrigenous organic materials. Rates of organic matter mineralization approximated by dissolved inorganic carbon fluxes at the sediment‐water interface reveal an approximately threefold higher rate at the trench axis sites than the abyssal sites. 210Pbxs profiles and burial of carbonate (up to 50%) at both trench axis sites reflect recent occurrence of mass‐wasting events possibly induced by earthquakes, which is responsible for the transport of preaged, terrigenous organic matter to the trench bottom. This tectonically triggered deposition event, which was also shown to occur in the Japan Trench, the Tonga Trench, and probably in many other trenches, is likely to efficiently transport terrigenous organic matter to hadal trenches, thereby underpinning the importance of terrigenous organic matter burial in hadal trenches for the ocean organic carbon budget. Furthermore, we hypothesize that hadal trenches may host a distinct microbial community that is capable of feeding on old, refractory terrigenous organic matter.

Document Type:	Article
Keywords:	Hadal trench terrigeneous organic matter shelf‐trench continuum mineralization mass‐wasting event
Research affiliation:	Kiel University > Kiel Marine Science OceanRep > The Future Ocean - Cluster of Excellence Kiel University
Refereed:	Yes
Open Access Journal?:	No
Publisher:	American Chemical Society
Projects:	Future Ocean
Date Deposited:	27 Aug 2019 10:39
Last Modified:	20 Jan 2020 11:32
URI:	https://oceanrep.geomar.de/id/eprint/47592

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