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Other research product . 2019

Long-chain diols in settling particles in tropical oceans: insights into sources, seasonality and proxies

Bar, Marijke W.; Ullgren, Jenny E.; Thunnell, Robert C.; Wakeham, Stuart G.; Brummer, Geert-Jan A.; Stuut, Jan-Berend W.; Sinninghe Damsté, Jaap S.; +1 Authors
Open Access
English
Published: 25 Apr 2019
Abstract
In this study we analyzed sediment trap time series from five tropical sites to assess seasonal variations in concentrations and fluxes of long-chain diols (LCDs) and associated proxies with emphasis on the long-chain diol index (LDI) temperature proxy. For the tropical Atlantic, we observe that generally less than 2 % of LCDs settling from the water column are preserved in the sediment. The Atlantic and Mozambique Channel traps reveal minimal seasonal variations in the LDI, similar to the two other lipid-based temperature proxies TEX86 and U37K′. In addition, annual mean LDI-derived temperatures are in good agreement with the annual mean satellite-derived sea surface temperatures (SSTs). In contrast, the LDI in the Cariaco Basin shows larger seasonal variation, as do the TEX86 and U37K′. Here, the LDI underestimates SST during the warmest months, which is possibly due to summer stratification and the habitat depth of the diol producers deepening to around 20–30 m. Surface sediment LDI temperatures in the Atlantic and Mozambique Channel compare well with the average LDI-derived temperatures from the overlying sediment traps, as well as with decadal annual mean SST. Lastly, we observed large seasonal variations in the diol index, as an indicator of upwelling conditions, at three sites: in the eastern Atlantic, potentially linked to Guinea Dome upwelling; in the Cariaco Basin, likely caused by seasonal upwelling; and in the Mozambique Channel, where diol index variations may be driven by upwelling from favorable winds and/or eddy migration.
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Funded by
EC| DUSTTRAFFIC
Project
DUSTTRAFFIC
Transatlantic fluxes of Saharan dust: changing climate through fertilising the ocean?
  • Funder: European Commission (EC)
  • Project Code: 311152
  • Funding stream: FP7 | SP2 | ERC
,
EC| DIOLS
Project
DIOLS
Long chain diols as novel organic proxies for paleoclimate reconstructions
  • Funder: European Commission (EC)
  • Project Code: 339206
  • Funding stream: FP7 | SP2 | ERC
,
NWO| TRAFFIC: Transatlantic fluxes of Saharan dust and ocean-climate impacts
Project
  • Funder: Netherlands Organisation for Scientific Research (NWO) (NWO)
  • Project Code: 2300175166
,
NWO| Perturbations of System Earth: Reading the Past to Project the Future - A proposal to create the Netherlands Earth System Science Centre (ESSC)
Project
  • Funder: Netherlands Organisation for Scientific Research (NWO) (NWO)
  • Project Code: 2300181601
Related to Research communities
European Marine Science Marine Environmental Science : Transatlantic fluxes of Saharan dust: changing climate through fertilising the ocean?
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