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
Filter
  • NIOZ_UU; NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University  (28)
  • Ocean Drilling Program; ODP  (5)
  • Diatoms  (2)
Document type
Keywords
Publisher
Years
  • 1
    facet.materialart.
    Unknown
    Rapid sulfurisation of highly branched isoprenoid (HBI) alkenes in sulfidic Holocene sediments from Ellis Fjord, Antarctica (2008)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Elsevier B.V., 2007. 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 Organic Geochemistry 38 (2007): 128-139, doi:10.1016/j.orggeochem.2006.08.003.
    Description: Samples of particulate organic matter from the water column and anoxic Holocene sediment layers from the Small Meromictic Basin (SMB) in Ellis Fjord (eastern Antarctica) were analyzed to study the early incorporation of reduced inorganic sulfur species into highly branched isoprenoid (HBI) alkenes. HBIs were not detected in the water column samples from austral winter, whereas compounds containing the C25 HBI skeleton were abundant in all analyzed Holocene sediment layers. The structure of the C25:2 HBI alkene together with its enriched stable carbon isotopic composition suggest that the HBI alkene is produced by a diatom or diatoms probably belonging to the Navicula genus present in the sea-ice which covers the area most of the year. Within just 500 years of deposition, all of the HBI alkene was sulfurised. A mixture of products was formed, including components tentatively identified as a C25 HBI thiane and three S-containing dimers composed of two C25:1 HBI skeletons linked together by a sulfide bond. Most of the HBI alkene, however, was converted to polar S-containing compounds. The observed reaction rate for sulfurisation the C25:2 HBI alkene is the highest observed so far in natural systems. Sterols and other lipids known to be prone to sulfurisation were only minimally sulfurised under these depositional conditions. The reason for this is presently unclear.
    Description: Funding for the collection of the sediment and water samples (by MJLC and CW) was provided by ASAC grant 1166 to JKV. This work was further supported by a grant from the Netherlands Organization for Scientific Research (NWO; Netherlands Antarctic Research Proposals 851.20.006 to JSSD).
    Keywords: Diatoms ; Thiane ; Euxinic conditions ; Sediment diagenesis ; Kinetics
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 2
    facet.materialart.
    Unknown
    Identification of organic matter sources in sulfidic late Holocene Antarctic fjord sediments from fossil rDNA sequence analysis (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 Paleoceanography 22 (2007): PA2211, doi:10.1029/2006PA001309.
    Description: The 18S ribosomal DNA (rDNA) isolated from sulfidic Holocene sediments and particulate organic matter in the water column of the stratified Small Meromictic Basin (SMB) in Ellis Fjord (eastern Antarctica) was analyzed to identify possible biological sources of organic matter. Previous work had shown that the sediments contained numerous diatom frustules and high contents of a highly branched isoprenoid (HBI) C25:2 alkene (which is a specific biomarker of certain species of the diatom genera Navicula, Haslea, Pleurosigma, or Rhizosolenia), so we focused our search on preserved fossil 18S rDNA of diatoms using sensitive polymerase chain reaction (PCR) approaches. We did not find diatom-derived fossil 18S rDNA using general eukaryotic primers, and even when we used primers selective for diatom 18S rDNA, we only identified a Chaetoceros phylotype, which is known to form cysts in the SMB but is not a likely source of the C25:2 HBI. When we used PCR/denaturing gradient gel electrophoresis methods specific to phylotypes within the HBI-biosynthesizing genera, we were able to identify three phylotypes in the sediments related to HBI-producing strains of the genera Haslea and Navicula. The ancient DNA data thus provided a limited, but valuable, view of the diversity of late Holocene primary producers with a particular bias to specific components of the biota that were better preserved such as the Chaetoceros cysts. This use of paleogenetics also revealed unexpected possible sources of organic matter such as novel stramenopiles for which no specific lipid biomarkers are known and thus would not have been identified based on traditional lipid stratigraphy alone.
    Description: Funding for the collection of the sediment and water samples (by M.J.L.C. and C.W.) was provided by the Australian Antarctic Science Advisory Committee (ASAC grant 1166 to J.K.V.). This work was further supported by grants from the Netherlands Organization for Scientific Research (NOW) (Netherlands Antarctic Research Proposals 851.20.020 to M.J.L.C. and 851.20.006 to J.S.S.D.).
    Keywords: Ancient DNA ; Diatoms ; Ellis Fjord
    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)
  • 3
    facet.materialart.
    Unknown
    Branched tetraether lipids from the Tagus River basin to the coastal ocean of the Portuguese margin
    PANGAEA
    In:  Supplement to: Zell, Claudia; Kim, Jung-Hyun; Balsinha, M; Dorhout, Denise J C; Fernandes, C; Baas, Marianne; Sinninghe Damsté, Jaap S (2014): Transport of branched tetraether lipids from the Tagus River basin to the coastal ocean of the Portuguese margin: consequences for the interpretation of the MBT'/CBT paleothermometer. Biogeosciences, 11(19), 5637-5655, https://doi.org/10.5194/bg-11-5637-2014
    Details
    Publication Date: 2023-05-12
    Description: Branched glycerol dialkyl glycerol tetraethers (brGDGTs), which are thought to be transported from soil to marine sediment by rivers, have been used to reconstruct the mean annual air temperature (MAAT) and soil pH of the drainage basin using the methylation index of branched tetraethers (MBT, recently refined as MBT') and cyclization index of branched tetraethers (CBT) from coastal marine sediment records. In this study we are tracing the brGDGTs from source to sink in the Tagus River basin, the longest river system on the Iberian Peninsula, by determining their concentration and distribution in soils, river suspended particulate matter (SPM), riverbank sediments, marine SPM, and marine surface sediments. The concentrations of brGDGTs in river SPM were substantially higher and their distributions were different compared to those of the drainage basin soils. This indicates that brGDGTs are mainly produced in the river itself. In the marine environment, the brGDGT concentrations rapidly decreased with increasing distance from the Tagus estuary. At the same time, the brGDGT distributions in marine sediments also changed, indicating that marine in-situ production also takes place. These results show that there are various problems that complicate the use of the MBT'/CBT for paleoreconstructions using coastal marine sediments in the vicinity of a river. However, if the majority of brGDGTs are produced in the river, it might be possible to reconstruct the environmental (temperature and pH) conditions of the river water using appropriate aquatic calibrations, provided that marine core locations are chosen in such a way that the brGDGTs in their sediments are predominantly derived from riverine in-situ production.
    Keywords: NIOZ_UU; NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University
    Type: Dataset
    Format: application/zip, 3 datasets
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    DATA PANGAEA
  • 4
    facet.materialart.
    Unknown
    Branched GDGTs of sediment and soil samples from Svalbard (2017)
    PANGAEA
    In:  Supplement to: Peterse, Francien; Kim, Jung-Hyun; Schouten, Stefan; Klitgaard-Kristensen, Dorthe; Koç, Nalân; Sinninghe Damsté, Jaap S (2009): Constraints on the application of the MBT/CBT palaeothermometer at high latitude environments (Svalbard, Norway). Organic Geochemistry, 40(6), 692-699, https://doi.org/10.1016/j.orggeochem.2009.03.004
    Details
    Publication Date: 2023-05-12
    Description: Branched glycerol dialkyl glycerol tetraethers (GDGTs) are membrane lipids of unknown bacteria that are ubiquitous in soil and peat. Two indices based on the distribution of these lipids in soils, the Cyclization of Branched Tetraethers (CBT) and the Methylation of Branched Tetraethers (MBT) indices have been shown to correlate with soil pH, and mean annual air temperature (MAT) and soil pH, respectively, and can be used to reconstruct MAT in palaeoenvironments. To verify the extent to which branched GDGTs in marine sediments reflect the distribution pattern on land and whether these proxies are applicable for palaeoclimate reconstruction in high latitude environments with a MAT of 〈0 °C, we compared the branched GDGT distribution in Svalbard soils and nearby fjord sediments. Although branched GDGT concentrations in the soil are relatively low (0.02-0.95 µg/g dry weight (dw)) because of the cold climate and the short growing season, reconstructed MATs based on the MBT/CBT proxy are ca. -4 °C, close to the measured MAT (ca. -6 °C). Concentrations of branched GDGTs (0.01-0.20 µg/g dw) in fjord sediments increased towards the open ocean and the distribution was strikingly different from that in soil, i.e. dominated by GDGTs with one cyclopentane moiety. This resulted in MBT/CBT-reconstructed MAT values of 11- 19 °C, well above measured MAT. The results suggest that at least part of the branched GDGTs in marine sediments in settings with a low soil organic matter (OM) input may be produced in situ. In these cases, the application of the MBT/CBT palaeothermometer will generate unrealistic MAT reconstructions. The MBT/CBT proxy should therefore only be used at sites with a substantial input of soil OM relative to the amount of marine OM, i.e. at sites close to the mouth of rivers with a catchment area where sufficient soil formation takes place and the soil thus contains substantial amounts of branched GDGTs.
    Keywords: NIOZ_UU; NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University
    Type: Dataset
    Format: application/zip, 3 datasets
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    DATA PANGAEA
  • 5
    facet.materialart.
    Unknown
    Mean annula temperature reconstruction for East Asia
    PANGAEA
    In:  Supplement to: Peterse, Francien; Prins, Maarten Arnoud; Beets, Christiaan J; Troelstra, Simon; Zheng, Hongbo; Gu, Zhaoyan; Schouten, Stefan; Sinninghe Damsté, Jaap S (2011): Decoupled warming and monsoon precipitation in East Asia over the last deglaciation. Earth and Planetary Science Letters, 301(1-2), 256-264, https://doi.org/10.1016/j.epsl.2010.11.010
    Details
    Publication Date: 2023-05-12
    Description: Our understanding of the continental climate development in East Asia is mainly based on loess-paleosol; sequences and summer monsoon precipitation reconstructions based on oxygen isotopes (?18O) of stalagmites from several Chinese caves. Based on these records, it is thought that East Asian Summer Monsoon (EASM) precipitation generally follows Northern Hemisphere (NH) summer insolation. However, not much is known about the magnitude and timing of deglacial warming on the East Asian continent. In this study we reconstruct continental air temperatures for central China covering the last 34,000 yr, based on the distribution of fossil branched tetraether membrane lipids of soil bacteria in a loess-paleosol sequence from the Mangshan loess plateau. The results indicate that air temperature varied in phase with NH summer insolation, and that the onset of deglacial warming at ~19 kyr BP is parallel in timing with other continental records from e.g. Antarctica, southern Africa and South-America. The air temperature increased from ~15 °C at the onset of the warming to a maximum of ~27 °C in the early Holocene (~12 kyr BP), in agreement with the temperature increase inferred from e.g. pollen and phytolith data, and permafrost limits in central China. Comparison of the tetraether membrane lipid-derived temperature record with loess-paleosol proxy records and stalagmite ?18O records shows that the strengthening of EASM precipitation lagged that of deglacial warming by ca. 3 kyr. Moreover, intense soil formation in the loess deposits, caused by substantial increases in summer monsoon precipitation, only started around 12 kyr BP (ca. 7 kyr lag). Our results thus show that the intensification of EASM precipitation unambiguously lagged deglacial warming and NH summer insolation, and may contribute to a better understanding of the mechanisms controlling ice age terminations.
    Keywords: NIOZ_UU; NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University
    Type: Dataset
    Format: application/zip, 3 datasets
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    DATA PANGAEA
  • 6
    facet.materialart.
    Unknown
    Branched GDGT lipids, crenarchaeol and POC in the Yenisei River (2009-2010)
    PANGAEA
    In:  Supplement to: De Jonge, Cindy; Stadnitskaia, Alina; Hopmans, Ellen C; Cherkashov, Georgy A; Fedotov, Andrey; Sinninghe Damsté, Jaap S (2014): In situ produced branched glycerol dialkyl glycerol tetraethers in suspended particulate matter from the Yenisei River, Eastern Siberia. Geochimica et Cosmochimica Acta, 125, 476-491, https://doi.org/10.1016/j.gca.2013.10.031
    Details
    Publication Date: 2023-05-12
    Description: Soil-derived branched glycerol dialkyl glycerol tetraethers (brGDGTs) in marine river fan sediments have a potential use for determining changes in the mean annual temperature (MAT) and pH of the river watershed soils. Prior to their incorporation in marine sediments, the compounds are transported to the marine system by rivers. However, emerging evidence suggests that the brGDGTs in freshwater systems can be derived from both soil run-off and in situ production. The production of brGDGTs in the river system can complicate the interpretation of the brGDGT signal delivered to the marine system. Therefore, we studied the distribution of brGDGT lipids in suspended particulate matter (SPM) of the Yenisei River. Chromatographic improvements allowed quantification of the recently described hexamethylated brGDGT isomer, characterized by having two methyl groups at the 6/6' instead of the 5/5' positions, in an environmental dataset for the first time. This novel compound was the most abundant brGDGT in SPM from the Yenisei. Its fractional abundance correlated well with that of the 6-methyl isomer of the hexamethylated brGDGT that contains one cyclopentane moiety. The Yenisei River watershed is characterized by large differences in MAT (〉11 °C) as it spans a large latitudinal range (46-73°N), which would be expected to be reflected in brGDGT distributions of its soils. However, the brGDGT distributions in its SPM show little variation. Furthermore, the reconstructed pH values are high compared to the watershed soil pH. We, therefore, hypothesize that the brGDGTs in the Yenisei River SPM are predominantly produced in situ and not primarily derived from erosion of soil. This accounts for the absence of a change in the temperature signal, as the river water temperature is more stable. Using a lake calibration, the reconstructed temperature values agree with the mean summer temperatures (MST) recorded. The brGDGTs delivered to the sea by the Yenisei River during this season are thus not soil-derived, possibly complicating the use of brGDGTs in marine sediments for palaeoclimate reconstructions.
    Keywords: NIOZ_UU; NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University
    Type: Dataset
    Format: application/zip, 6 datasets
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    DATA PANGAEA
  • 7
    facet.materialart.
    Unknown
    Biomarker evidence for anammox in the oxygen minimum zone of the Eastern Tropical North Pacific
    PANGAEA
    In:  Supplement to: Rush, Darci; Wakeham, Stuart G; Hopmans, Ellen C; Schouten, Stefan; Sinninghe Damsté, Jaap S (2012): Biomarker evidence for anammox in the oxygen minimum zone of the Eastern Tropical North Pacific. Organic Geochemistry, 53, 80-87, https://doi.org/10.1016/j.orggeochem.2012.02.005
    Details
    Publication Date: 2023-05-12
    Description: Anaerobic oxidation of ammonium (anammox) is an important process in the marine nitrogen cycle. It has been estimated to contribute up to 50% of nitrogen loss from the ocean, and is especially prevalent within oxygen minimum zones (OMZs). Here we studied the presence and distribution of anammox in the extended OMZ of the Eastern Tropical North Pacific (ETNP) using ladderane fatty acids, specific biomarkers for anammox bacteria. The validity of ladderane fatty acids as proxies for anammox bacteria was demonstrated by their excellent correspondence with anammox 16S rRNA functional gene abundances and their expression and intact polar ladderane lipid concentrations in suspended particulate matter (SPM) from the Arabian Sea. In the ETNP, SPM was collected from various water depths at four stations along a northwest to southeast cruise transect and ladderane fatty acids were analyzed at each station. In all SPM samples where ladderane lipids were detected, C18 ladderane fatty acids were on average 5 fold more abundant than C20 ladderane fatty acids. Maximum concentrations in ladderane fatty acids (1.1 - 2.3 ng/l) were recorded at 400-600 m water depth, often corresponding to the depth of the secondary nitrite maximum. In one of the four stations, a second maximum in the ladderane fatty acid concentration was noted at a shallower depth (i.e. at 85 m), coinciding with higher nitrite concentrations at this water depth. The availability of nitrite probably limits anammox activity in the ETNP. Anammox lipids were abundant within the OMZ at all stations and concentrations were comparable to those in other OMZs, suggesting that anammox may be responsible for a significant loss of nitrogen in the OMZ of the ETNP.
    Keywords: NIOZ_UU; NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University
    Type: Dataset
    Format: application/zip, 2 datasets
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    DATA PANGAEA
  • 8
    facet.materialart.
    Unknown
    Branched GDGTs in the Tagus River drainage basin and its outflow into the Atlantic Ocean
    PANGAEA
    In:  Supplement to: Warden, Lisa; Kim, Jung-Hyun; Zell, Claudia; Vis, Geert-Jan; de Stigter, Henko; Bonnin, Jerome; Sinninghe Damsté, Jaap S (2016): Examining the provenance of branched GDGTs in the Tagus River drainage basin and its outflow into the Atlantic Ocean over the Holocene to determine their usefulness for paleoclimate applications. Biogeosciences, 13(20), 5719-5738, https://doi.org/10.5194/bg-13-5719-2016
    Details
    Publication Date: 2023-05-12
    Description: The distributions of branched glycerol dialkyl glycerol tetraethers (brGDGTs), which are transported from the soils where they are predominantly produced to marine sediments via rivers, have been applied in reconstructing mean annual air temperature (MAT) and pH of soils. However, paleoclimate reconstructions using sedimentary brGDGTs have proven difficult in arid regions, including the Iberian Peninsula. Recently, six novel 6-methyl brGDGTs have been described using new analytical methods (in addition to the nine 5-methyl brGDGTs previously used for climate reconstructions), and so new pH and MAT calibrations have been developed that were shown to improve the accuracy of reconstructions in a set of global soil samples, especially in arid regions. Because of this we decided to apply the new method to separate the 5- and 6-methyl isomers along with the novel calibrations to a sample set from the Iberian Peninsula to determine whether it improves paleoclimate reconstructions in this area. This set includes samples that run in a transect from source to sink along the Tagus River and out to the deep ocean off the Portuguese margin spanning the last 6000 years. We found that although pH reconstructions in the soils were improved using the new calibration, MAT reconstructions were not much better even with the separation of the 5- and 6-methyl brGDGTs. This confirmed the conclusion of previous studies that the amount of aquatically produced brGDGTs is overwhelming the soil-derived ones in marine sediments and complicating MAT reconstructions in the region. Additionally, the newseparation revealed a strong and until now unseen relationship between the new degree of cyclization (DC') of the brGDGTs and MAT that could be making temperature reconstructions in this and other arid regions difficult
    Keywords: NIOZ_UU; NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University
    Type: Dataset
    Format: application/zip, 3 datasets
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    DATA PANGAEA
  • 9
    facet.materialart.
    Unknown
    Stable hydrogen and carbon isotopes of C37 alkenones during Termination I and II
    PANGAEA
    In:  Supplement to: Kasper, Sebastian; van der Meer, Marcel T J; Mets, Anchelique; Zahn, Rainer; Sinninghe Damsté, Jaap S; Schouten, Stefan (2014): Salinity changes in the Agulhas leakage area recorded by stable hydrogen isotopes of C37 alkenones during Termination I and II. Climate of the Past, 10(1), 251-260, https://doi.org/10.5194/cp-10-251-2014
    Details
    Publication Date: 2023-05-12
    Description: At the southern tip of Africa, the Agulhas Current reflects back into the Indian Ocean causing so-called "Agulhas rings" to spin off and release relatively warm and saline water into the South Atlantic Ocean. Previous reconstructions of the dynamics of the Agulhas Current, based on paleo-sea surface temperature and sea surface salinity proxies, inferred that Agulhas leakage from the Indian Ocean to the South Atlantic was reduced during glacial stages as a consequence of shifted wind fields and a northwards migration of the subtropical front. Subsequently, this might have led to a buildup of warm saline water in the southern Indian Ocean. To investigate this latter hypothesis, we reconstructed sea surface salinity changes using alkenone dD, and paleo-sea surface temperature using TEXH 86 and UK'37, from two sediment cores (MD02-2594, MD96-2080) located in the Agulhas leakage area during Termination I and II. Both UK'37 and TEXH 86 temperature reconstructions indicate an abrupt warming during the glacial terminations, while a shift to more negative dDalkenone values of approximately 14 per mil during glacial Termination I and II is also observed. Approximately half of the isotopic shift can be attributed to the change in global ice volume, while the residual isotopic shift is attributed to changes in salinity, suggesting relatively high salinities at the core sites during glacials, with subsequent freshening during glacial terminations. Approximate estimations suggest that dDalkenone represents a salinity change of ca. 1.7-1.9 during Termination I and Termination II. These estimations are in good agreement with the proposed changes in salinity derived from previously reported combined planktonic Foraminifera d18O values and Mg/Ca-based temperature reconstructions. Our results confirm that the dD of alkenones is a potentially suitable tool to reconstruct salinity changes independent of planktonic Foraminifera d18O.
    Keywords: NIOZ_UU; NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University
    Type: Dataset
    Format: application/zip, 2 datasets
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    DATA PANGAEA
  • 10
    facet.materialart.
    Unknown
    Branched GDGT and crenarchaeol lipids, and bulk parameters (TOC, TN, C/N, δ¹³C and d15N) in the Yenisei River and its outflow in the Kara Sea
    PANGAEA
    In:  Supplement to: De Jonge, Cindy; Stadnitskaia, Alina; Hopmans, Ellen C; Cherkashov, Georgy A; Fedotov, Andrey; Streletskaya, Irina; Vasiliev, Alexander A; Sinninghe Damsté, Jaap S (2015): Drastic changes in the distribution of branched tetraether lipids in suspended matter and sediments from the Yenisei River and Kara Sea (Siberia): Implications for the use of brGDGT-based proxies in coastal marine sediments. Geochimica et Cosmochimica Acta, 165, 200-225, https://doi.org/10.1016/j.gca.2015.05.044
    Details
    Publication Date: 2023-05-12
    Description: The distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in soils has been shown to correlate with pH and mean annual air temperature. Because of this dependence brGDGTs have found an application as palaeoclimate proxies in coastal marine sediments, based on the assumption that their distribution is not altered during the transport from soils to marine systems by rivers. To study the processes acting on the brGDGT distributions, we analysed the full suite of brGDGTs, including the recently described 6-Me brGDGTs, in both the suspended particulate matter (SPM) of the Siberian Yenisei River and the SPM and sediments of its outflow in the Kara Sea. The brGDGT distribution in the SPM of the Yenisei River was fairly constant and characterized by high abundances of the 6-Me brGDGTs, reflecting their production at the neutral pH of the river water. However, the brGDGT distribution showed marked shifts in the marine system. Firstly, in the Yenisei River Mouth, the fractional abundance of the 6-Me brGDGTs decreases sharply. The brGDGT signature in the Yenisei River Mouth possibly reflects brGDGTs delivered during the spring floods that may carry a different distribution. Also, coastal cliffs were shown to contain brGDGTs and to influence especially those sites without major river inputs (e.g. Khalmyer Bay). Further removed from the river mouth, in-situ production of brGDGTs in the marine system influences the distribution. However, also the fractional abundance of the tetramethylated brGDGT Ia increases, resulting in a distribution that is distinct from in-situ produced signals at similar latitudes (Svalbard). We suggest that this shift may be caused by preferential degradation of labile (riverine in-situ produced) brGDGTs and the subsequent enrichment in less labile (soil) material. The offshore distribution indeed agrees with the brGDGT distribution encountered in a lowland peat. This implies that the offshore Kara Sea sediments possibly carry a soil-dominated signal, indicating potential for palaeoclimate reconstructions at this site. Both in the river system and coastal cliffs, brGDGTs were much more abundant than crenarchaeol, an archaeal isoprenoid GDGT, resulting in high (〉0.93) Branched and Isoprenoid Tetraether (BIT) index values. Moving downstream in the marine sediments, a decrease in brGDGT concentrations, coeval with an increase in crenarchaeol, resulted in decreasing BIT index values. This decrease correlates with changes in bulk proxies for terrigenous input (d13Corg, C/N), confirming the use of the BIT index to trace the delivery of river-transported and coastal cliff-derived terrigenous organic matter.
    Keywords: NIOZ_UU; NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University
    Type: Dataset
    Format: application/zip, 5 datasets
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    DATA PANGAEA
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...