GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Lateral organic carbon supply to the deep Canada Basin (2010)
    American Geophysical Union
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 35 (2008): L11607, doi:10.1029/2008GL034271.
    Description: Understanding the processes driving the carbon cycle in the Arctic Ocean is important for assessing the impacts of the predicted rapid and amplified climate change in this region. We analyzed settling particle samples intercepted by a time-series sediment trap deployed in the abyssal Canada Basin (at 3067 m) in order to examine carbon export to the deep Arctic Ocean. Strikingly old radiocarbon ages (apparent mean 14C age = ∼1900 years) of the organic carbon, abundant lithogenic material (∼80%), and mass flux variations temporally decoupled from the cycle of primary productivity in overlying surface waters together suggest that, unlike other ocean basins, the majority of the particulate organic carbon entering the deep Canada Basin is supplied from the surrounding margins.
    Description: This research was funded by the NSF Ocean Sciences Division (Chemical Oceanography program) and NSF Office of Polar Programs, Office of Naval Research, as well as the Ocean and Climate Change Institute and Arctic Research Initiative at the Woods Hole Oceanographic Institution.
    Keywords: POC ; Lateral transport ; Canada Basin
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 2
    facet.materialart.
    Unknown
    Rapid lateral particle transport in the Argentine Basin : molecular C-14 and Th-230(xs) evidence (2006)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Elsevier B.V., 2006. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 53 (2006): 1224-1243, doi:10.1016/j.dsr.2006.05.005.
    Description: Recent studies have revealed that lateral transport and focusing of particles strongly influences the depositional patterns of organic matter in marine sediments. Transport can occur in the water column prior to initial deposition or following sediment re-suspension. In both cases, fine-grained particles and organic-rich aggregates are more susceptible to lateral transport than coarse-grained particles (e.g. foraminiferal tests) because of the slower sinking velocities of the former. This may lead to spatial and, in the case of redistribution of resuspended sediments, temporal decoupling of organic matter from coarser sediment constituents. Prior studies from the Argentine Basin have yielded evidence that suspended particles are displaced significant distances (100 - 1000 km) northward and downslope by strong surface and/or bottom currents. These transport processes result in anomalously cold alkenone-derived sea surface temperature (SST) estimates (up to 6°C colder than measured SST) and in the presence of frustules of Antarctic diatom species in surface sediments fromthis area. Here we examine advective transport processes through combined measurements of compound-specific radiocarbon ages of marine phytoplankton derived biomarkers (alkenones) from core-tops and excess 230Th (230Thxs)-derived focusing factors for late Holocene sediments from the Argentine Basin. On the continental slope, we observe 230Thxs-based focusing factors of 1.4 to 3.2 at sites where alkenone-based SST estimates were 4–6°C colder than measured values. In contrast, alkenone radiocarbon data suggest coeval deposition of marine biomarkers and planktic foraminifera, as alkenones in core-tops were younger than, or similar in age to, foraminifera. We therefore infer that the transport processes leading to the lateral displacement of these sediment components are rapid, and hence probably occur in the upper water column (〈1500 m).
    Description: This work was funded by NSF grant #OCE-0327405 and a WHOI-NOSAMS postdoctoral scholarship to GM, and by support from NSF and the Gary Comer Science and Education Foundation to JFM.
    Keywords: Sediment transport ; Radiocarbon dating ; Sea-surface temperatures ; Core-top sediments ; South Atlantic Ocean ; Argentine and Brazil Basins ; Brazil-Malvinas Confluence
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
    Format: 1583514 bytes
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 3
    facet.materialart.
    Unknown
    Aging of marine organic matter during cross-shelf lateral transport in the Benguela upwelling system revealed by compound-specific radiocarbon dating (2010)
    American Geophysical Union
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2007. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 8 (2007): Q09004, doi:10.1029/2007GC001603.
    Description: Organic matter accumulation and burial on the Namibian shelf and upper slope are spatially heterogeneous and strongly controlled by lateral transport in subsurface nepheloid layers. Much of the material deposited in depo-centers on the slope ultimately derives from the shelf. Supply of organic matter from the shelf involves selective transport of organic matter. We studied these selective transport processes by analyzing the radiocarbon content of co-occurring sediment fractions. Here we present radiocarbon data for total organic carbon as well as three tracers of surface ocean productivity (phytoplankton-derived alkenones, membrane lipids of pelagic crenarchaeota (crenarchaeol), and calcareous microfossils of planktic foraminifera) in core-top and near-surface sediment samples. The samples were collected on the Namibian margin along a shelf-slope transect (85 to 1040 m) at 24°S and from the upper slope depo-center at 25.5°S. In core-top sediments, alkenone ages gradually increased from modern to 3490 radiocarbon years with distance from shore and with water depth. Crenarchaeol, while younger than alkenones, also increased in age with distance offshore. It was concluded that the observed ages were a consequence of cross-shelf transport and associated aging of organic matter. Radiocarbon ages of preserved lipid biomarkers in sediments thus at least partially depend on the relative amount of laterally supplied, pre-aged material present in a sample, highlighting the importance of nepheloid transport for the sedimentation of organic matter over the Namibian margin.
    Description: This work was funded by NSF grant OCE- 0327405 to T.I.E. and by a Spinoza grant to J.S.S.D. from NWO.
    Keywords: Compound-specific radiocarbon dating ; Sediment transport
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 4
    facet.materialart.
    Unknown
    Temporal and spatial variability of particle transport in the deep Arctic Canada Basin (2015)
    John Wiley & Sons
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Oceans 120 (2015): 2784–2799, doi:10.1002/2014JC010643.
    Description: To better understand the current carbon cycle and potentially detect its change in the rapidly changing Arctic Ocean, we examined sinking particles collected quasi-continuously over a period of 7 years (2004–2011) by bottom-tethered sediment trap moorings in the central Canada Basin. Total mass flux was very low (〈100 mg m−2 d−1) at all sites and was temporally decoupled from the cycle of primary production in surface waters. Extremely low radiocarbon contents of particulate organic carbon and high aluminum contents in sinking particles reveal high contributions of resuspended sediment to total sinking particle flux in the deep Canada Basin. Station A (75°N, 150°W) in the southwest quadrant of the Canada Basin is most strongly influenced while Station C (77°N, 140°W) in the northeast quadrant is least influenced by lateral particle supply based on radiocarbon content and Al concentration. The results at Station A, where three sediment traps were deployed at different depths, imply that the most likely mode of lateral particle transport was as thick clouds of enhanced particle concentration extending well above the seafloor. At present, only 1%–2% of the low levels of new production in Canada Basin surface waters reaches the interior basin. Lateral POC supply therefore appears to be the major source of organic matter to the interior basin. However, ongoing changes to surface ocean boundary conditions may influence both lateral and vertical supply of particulate material to the deep Canada Basin.
    Description: This research was funded by the NSF Division of Polar Programs (ARC-0909377), the Ocean and Climate Change Institute of Woods Hole Oceanographic Institution, and ETH Zürich. J.H. and M.K. were partly supported by the National Research Foundation of Korea grant funded by the Korean Government (2011–0013629).
    Keywords: Canada Basin ; Particulate organic carbon ; Lateral supply ; Radiocarbon ; Carbon cycle
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Format: application/vnd.ms-excel
    Format: application/msword
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...