|
|
|
|
|
| Dessandier, Pierre-antoine; Bonnin, Jerome; Kim, Jung-hyun; Bichon, Sabrina; Deflandre, Bruno; Gremare, Antoine; Damste, Jaap S. Sinninghe. |
| Living (rose Bengal stained) benthic foraminifera were investigated on surface sediments from 23 stations from the river-dominated northwestern Portuguese margin. Samples were collected in March 2011, following the period of the maximum rainfall over the Iberian Peninsula, between 20 and 2000m water depth along five cross-margin transects. Four of them are located off the Douro, Mondego, Tagus, and Sado Rivers and one off the Estremadura coast. The major objectives of this study are (1) to assess the impact of organic matter of various origin and quality on the benthic foraminifera and (2) to investigate the spatial differences of faunal distribution from coastal waters to the deep sea under river influences. To do this, sedimentological and biogeochemical... |
| Tipo: Text |
Palavras-chave: Benthic foraminiferal ecology; Fluvial influence; Organic matter quality; Portuguese margin. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00667/77896/80083.pdf |
| |
|
|
| Russ, Lina; Kartal, Boran; Op Den Camp, Huub J. M.; Sollai, Martina; Le Bruchec, Julie; Caprais, Jean-claude; Godfroy, Anne; Damste, Jaap S. Sinninghe; Jetten, Mike S. M.. |
| Hydrothermally active sediments are highly productive, chemosynthetic areas which are characterized by the rapid turnover of particulate organic matter under extreme conditions in which ammonia is liberated. These systems might be suitable habitats for anaerobic ammonium oxidizing (anammox) bacteria but this has not been investigated in detail. Here we report the diversity and abundance of anammox bacteria in sediments that seep cold hydrocarbon-rich fluids and hydrothermal vent areas of the Guaymas Basin in the Cortes Sea using the unique functional anammox marker gene, hydrazine synthase (hzsA). All clones retrieved were closely associated to the "Candidatus Scalindua" genus. Phylogenetic analysis revealed two distinct clusters of hzsA sequences (Ca.... |
| Tipo: Text |
Palavras-chave: Anammox; HzsA; AprA; Hydrothermal vents; Cold seep; Sulfide. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00180/29156/27555.pdf |
| |
|
|
| Lopes Dos Santos, Raquel A.; Spooner, Michelle I.; Barrows, Timothy T.; De Deckker, Patrick; Damste, Jaap S. Sinninghe; Schouten, Stefan. |
| Several proxies have been developed to reconstruct past sea surface temperature (SST), but different proxies may reflect temperatures of different seasons and each proxy is characterized by certain uncertainties. Therefore, a multiproxy approach is preferred to precisely reconstruct SST. Here, we reconstruct SST of the ocean offshore southeastern Australia (Murray Canyons area) for the last ~135 ka using three independent organic proxies (TEXH86 based on glycerol dialkyl glycerol tetraethers (GDGTs), UK'37 based on alkenones, and LDI based on long-chain diols) in addition to foraminiferal faunal assemblages. The organic proxy records show similar trends, with the highest temperature (21°C for UK'37 and TEXH86, and 25°C for LDI) during the last interglacial... |
| Tipo: Text |
Palavras-chave: Sea surface temperature; LDI index; TEX86H index; U-37(K') index; Foraminiferal assemblages; SE Australia. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00246/35763/34274.pdf |
| |
|
|
| Kaiser, Jerome; Schouten, Stefan; Kilian, Rolf; Arz, Helge W.; Lamy, Frank; Damste, Jaap S. Sinninghe. |
| Proxies based on glycerol dialkyl glycerol tetraether (GDGT) lipids from archaea [isoprenoid GDGTs] and bacteria [branched (br) GDGTs] in 33 surface sediments from marine, fjord and lake systems between 25°S and 50°S in Chile were analyzed. The regional TEXH86 calibration obtained from the marine and fjord sediments and mean annual surface temperature (T = 59.6 × TEXH86 + 33.0; r2 0.9; n = 23) is statistically identical to the global ocean calibration based on suspended particulate material in terms of slope, but not in terms of intercept. The regional surface and subsurface TEXH86 calibrations were statistically different from the existing global ocean core top calibrations. The TEX86 calibration model based on most of the relatively large lakes studied... |
| Tipo: Text |
Palavras-chave: GDGT; TEX86; BIT; MBT '; CBT; Calibration; Marine; Fjord; Lake; Chile. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00294/40524/39313.pdf |
| |
|
|
| Kim, Jung-hyun; Buscail, Roselyne; Fanget, Anne-sophie; Eyrolle-boyer, Frederique; Bassetti, Maria-angela; Dorhout, Denise; Baas, Marianne; Berne, Serge; Damste, Jaap S. Sinninghe. |
| We tested the applicability of the BIT (branched and isoprenoid tetraether) index as a proxy for palaeoflood events in the river-dominated continental margin of the Gulf of Lions (NW Mediterranean). We compared the concentrations of branched glycerol dialkyl glycerol tetraethers (br GDGTs) and crenarchaeol in suspended particulate matter (SPM) collected downstream in the Rhône River, as well as in surface sediments and a ca. 8m piston core from the Rhône prodelta. The core covered the last 400 yr, with four distinct intervals recording the river influence under natural and man-induced shifts in four main channels of the river mouth (Bras de Fer, Grand Rhône, Pégoulier,and Roustan). The results indicate that there are mixed sources of br GDGTs and... |
| Tipo: Text |
Palavras-chave: Palaeoflood; BIT index; GDGTs; Rhone prodelta. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00198/30969/29345.pdf |
| |
|
|
| Jaeschke, Andrea; Ziegler, Martin; Hopmans, Ellen C.; Reichart, Gert-jan; Lourens, Lucas J.; Schouten, Stefan; Damste, Jaap S. Sinninghe. |
| Anaerobic ammonium oxidation (anammox) has been recognized as an important process converting fixed nitrogen to N(2) in many marine environments, thereby having a major impact on the present-day marine nitrogen cycle. However, essentially nothing is known about the importance of anammox in past marine nitrogen cycles. In this study, we analyzed the distribution of fossil ladderane lipids, derived from bacteria performing anammox, in a sediment core from the northern Arabian Sea. Concentrations of ladderane lipids varied between 0.3 and 5.3 ng g(-1) sediment during the past 140 ka, with high values observed during the Holocene, intervals during the last glacial, and during the penultimate interglacial. Maxima in ladderane lipid abundances correlate with... |
| Tipo: Text |
|
| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00218/32942/31436.pdf |
| |
|
|
| Van Maldegem, Lennart M.; Sansjofre, Pierre; Weijers, Johan W. H.; Wolkenstein, Klaus; Strother, Paul K.; Woermer, Lars; Hefter, Jens; Nettersheim, Benjamin J.; Hoshino, Yosuke; Schouten, Stefan; Damste, Jaap S. Sinninghe; Nath, Nilamoni; Griesinger, Christian; Kuznetsov, Nikolay B.; Elie, Marcel; Elvert, Marcus; Tegelaar, Erik; Gleixner, Gerd; Hallmann, Christian. |
| Eukaryotic algae rose to ecological relevance after the Neoproterozoic Snowball Earth glaciations, but the causes for this consequential evolutionary transition remain enigmatic. Cap carbonates were globally deposited directly after these glaciations, but they are usually organic barren or thermally overprinted. Here we show that uniquely-preserved cap dolostones of the Araras Group contain exceptional abundances of a newly identified biomarker: 25,28-bisnorgammacerane. Its secular occurrence, carbon isotope systematics and co-occurrence with other demethylated terpenoids suggest a mechanistic connection to extensive microbial degradation of ciliate-derived biomass in bacterially dominated ecosystems. Declining 25,28-bisnorgammacerane concentrations, and a... |
| Tipo: Text |
|
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00637/74951/76030.pdf |
| |
|
|
| Kim, Jung-hyun; Crosta, Xavier; Willmott, Veronica; Renssen, Hans; Bonnin, Jerome; Helmke, Peer; Schouten, Stefan; Damste, Jaap S. Sinninghe. |
| We reconstructed subsurface (similar to 45-200 m water depth) temperature variability in the eastern Antarctic continental margin during the late Holocene, using an archaeal lipid-based temperature proxy (TEX86 L). Our results reveal that subsurface temperature changes were probably positively coupled to the variability of warmer, nutrient-rich Modified Circumpolar Deep Water (MCDW, deep water of the Antarctic circumpolar current) intrusion onto the continental shelf. The TEX86 L record, in combination with previously published climatic records, indicates that this coupling was probably related to the thermohaline circulation, seasonal variability in sea ice extent, sea temperature, and wind associated with high frequency climate dynamics at low-latitudes... |
| Tipo: Text |
|
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00265/37669/36859.pdf |
| |
|
|
|
