Salvatteci, Renato; Field, David; Gutièrrez, Dimitri; Baumgartner, Tim; Ferreira, Leonardo V; Ortlieb, Luc; Sifeddine, Abdelfettah; Grados, Carmen; Bertrand, Arnaud
The Humboldt Current System (HCS) has the highest production of forage fish in the world, although it is highly variable and the future of the primary component, anchovy, is uncertain in the context of global warming. Paradigms based on late 20th century observations suggest that large-scale forcing controls decadal-scale fluctuations of anchovy and sardine across different boundary currents of the Pacific. We develop records of anchovy and sardine fluctuations since 1860 AD using fish scales from multiple sites containing laminated sediments and compare them with Pacific basin-scale and regional indices of ocean climate variability. Our records reveal two main anchovy...
Samples of algae and sediment were taken between July 1973 and May 1975 at intervals of 2-5 weeks from a number of depths at the entrance of Eckernförder Bay (Western Baltic Seal. The purpose was to ascertain the correlation between the settlement of foraminifera and ecofactors, and to determine the annual carbonate production by foraminifera. Produection data were compared with the foraminifera content of the sediments. Information on the extend and place of dissolution could be gained by measuring the saturation of the water with mineral carbonates.
The exact area of colonisation (=sediment surfaee, in the sediment or on algae, Fig....
Zhuang, Guang-Chao; Lin, Yu-Shih; Bowles, Marshall W; Heuer, Verena B; Lever, Mark A; Elvert, Marcus; Hinrichs, Kai-Uwe
Methylated amines and sulfides are ubiquitous organic nitrogen and sulfur compounds in the marine environment and could serve as important energy substrates to methanogens inhabiting anoxic sediments. However, their abundance and isotopic values remain largely unconstrained in marine sediments. In this study, we investigated the distribution of trimethylamine (TMA), dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) in Aarhus Bay, Denmark and provided the first report for their stable carbon isotopic composition. Simultaneous measurement of those two compounds in small volumes of pore waters and sediments was accomplished with gas chromatography in combination with either a purge and trap system for quantification or...
Coch, Caroline; Lamoureux, Scott; Knoblauch, Christian; Eischeid, Isabell; Fritz, Michael; Obu, Jaroslav; Lantuit, Hugues
Water samples were collected at the outflow of Ice Creek West on Herschel Island, Yukon Territory, Canada in the summers of 2014, 2015 and 2016 using an automatic water sampler (ISCO 3700).
Reyss, Jean-Louis; Yokoyama, Y
Manganese nodules are generally considered to have accumulated very slowly. Radiometric studies by 230Th, 231Pa, and 234U/238U suggest their growth rates to be a few mm per 10 million yr. This leads to an enigma: how do they escape from burial by associated marine sediments which are accumulating three orders of magnitude faster than the nodules? Though this problem remains open, the postulated slow growth rates might permit manganese nodules to accumulate in a small volume high concentrations of long lived cosmogenic radionuclides 10Be (half tau = 1.5 Myr) and 26Al (half tau = 0.715 Myr) which were formed through...
Das untersuchte Sedimentmaterial stammt aus dem westlich des Gunnerus-Rückens liegenden Tiefseebereich des Riiser-Larsenmeeres aus ca. 4480 m Wassertiefe. An den unverfestigten Sedimentkernproben eines etwa 13,40 m langen Schwerelotes (PS1824-1) und eines ca. 50 cm langen Großkastengreifers (PS1824-2) wurden umfangreiche sedimentphysikalische und sedimentologische Untersuchungsmethoden angewandt. Neben zerstörungsfreien, sedimentphysikalischen Messungen zur Ermittlung von Suszeptibilität, elektrischen Widerstand, P-Wellengeschwindigkeit und Feuchtraumdichte, wurden unter anderem die Korngrößenverteilung, der Karbonat- und Corg-Gehalt sowie die Komponentenverteilung der Sandfraktion bestimmt. Die zeitliche Einstufung basiert auf biostratigraphischen Datierungsmethoden mit Hilfe von Radiolarien und Diatomeen. Die untersuchten Sedimente umfassen demnach einen Ablagerungszeitraum vom Pliozän bis in das Holozän. Die Abfolgen...
Taboada, Sergi; Riesgo, Ana; Wiklund, Helena; Paterson, Gordon L J; Koutsouveli, Vasiliki; Santodomingo, Nadia; Dale, Andrew C; Smith, Craig R; Jones, Daniel O B; Dahlgren, Thomas G; Glover, Adrian G
The excel file has two spread-sheets: (i) "Microsatellites-4Areas" including the information of the 11 microsatellites used in the paper for the four different areas we investigated; (ii) "Microsatellites-30Populations" including the information of the 11 microsatellites used in the paper for the 30 different populations we investigated.
In the two spread-sheets we include the following columns: "Number of individual" from 1 to 168; "Area" with the names of the areas or populations for every individual; "Sample Code" with the name of the sample used in the paper; "1Ple, 3Ple, 11Ple, 13Ple, 12Ple, 14Ple, 16Ple, 5Ple, 19Ple, 10Ple, and 2Ple" the name of...
LeKieffre, Charlotte; Spero, Howard J; Russell, Ann D; Fehrenbacher, Jennifer; Geslin, Emmanuelle; Meibom, Anders
Here we performed pulse-chase experiments with 13C-enriched dissolved inorganic carbon, followed by TEM and quantitative NanoSIMS isotopic imaging to visualize photosynthetic C assimilation by individual symbiotic dinoflagellates and subsequent translocation to their Orbulina universa host.
NanoSIMS image processing was carried out as described in LeKieffre et al. (2017) and Nomaki et al. (2018). Briefly, TEM images were aligned with corresponding NanoSIMS 12C14N- images (Online Resource 1) using the software Look@NanoSIMS (Polerecky et al. 2012), which allows a user to hand-draw regions of interest (ROIs) corresponding to different organelles (e.g., dinoflagellate starch grains, foraminiferal lipid droplets, and fibrillar bodies). For each type...
Wündsch, Michael; Haberzettl, Torsten; Cawthra, Hayley; Kirsten, Kelly L; Quick, Lynne J; Zabel, Matthias; Frenzel, Peter; Hahn, Annette; Baade, Jussi; Daut, Gerhard; Kasper, Thomas; Meadows, Michael E; Mäusbacher, Roland
This study investigates Holocene sediments from Eilandvlei, a coastal lake located within the Wilderness embayment at the southern Cape coast of South Africa. The evolution of the present estuarine/coastal lake system is reconstructed based on seismic data as well as a multi-proxy approach on a 30.5 m sediment core spanning the last ~8.9 kyr. Geochemical (Ca, TOC/S, Br/TOC) and micropalaeontological data (diatoms, foraminifera) reflect changes in the degree of marine influence at the core site. The embayment likely developed via distinct phases of connectivity to the Indian Ocean caused by sea level changes and dune progradation. Marine conditions prevailed at...
Ergebnisse: Durch konsequente Verfolgung der Tephrostratigraphie ergibt sich ein klareres Bild des neubearbeiteten Ausschnittes des Ebbe-Sattels.
- Verseschichten kommen im kartierten Gebiet nicht vor.
- Es ließen sich keine Winkeldiskordanzen oder Sedimentationslücken feststellen.
- Im Hangenden der Bunten Ebbe-Gruppe kann entweder der Fahlenscheid-Vulkanit oder der Rehberg-Horizont kartiert werden, was ein Beweis für die Zeitgleichheit von beiden ist.
- Der Haupt-Vulkanit ist zu Teilen mit Sicherheit subaerisch abgelagert worden: Die Felsokeratophyre und manche Tuffe zeigen ignimbritische Strukturen und im obersten Teil des Vulkanits finden sich "accretionary lapilli".
- Die Haupt-Sattelachse des kartierten Sattels liegt nördlicher als FUCHS angenommen hat, nämlich zwischen Hüttebruch und Vor der Mark.
Méheust, Marie; Stein, Ruediger; Fahl, Kirsten; Gersonde, Rainer
This study focusses on the last glacial-deglacial-Holocene spatial and temporal variability in sea-ice cover based on organic geochemical analyses of marine sediment cores from the subarctic Pacific and the Bering Sea. By means of the sea ice proxy "IP25/PIP25" and phytoplankton-derived biomarkers (specific sterols and alkenones), we reconstruct the spring sea-ice conditions, (summer) sea-surface temperature (SST) and primary productivity, respectively. The large variability of sea ice was explained by a combination of local and global factors, such as solar insolation, global climate anomalies and sea-level changes controlling the oceanographic circulation and water mass exchange between the subarctic Pacific and the...
Hansen, Christian T; Meixner, A; Kasemann, Simone A; Bach, Wolfgang
Multiple batch experiments (100 °C, 200 °C; 40 MPa) were conducted, using Dickson-type reactors, to investigate Li and B partitioning and isotope fractionation between rock and water during serpentinization. We reacted fresh olivine (5 g; Fo90; [B] = <0.02 µg/g; d11BOlivine -14 per mil; [Li] = 1.7 µg/g; d7LiOlivine = +5.3 per mil) with seawater-like fluids (75 ml, 3.2 wt.% NaCl) adjusted with respect to their Li (0.2, 0.5 µg/ml; and d7LiFluid +55 per mil) and B (~10 µg/ml and d11BFluid -0.3 per mil) characteristics. At 200 °C a reaction turnover of about 70% and a serpentinization mineral assemblage matching...
Crivellari, Stefano; Chiessi, Cristiano Mazur; Kuhnert, Henning; Häggi, Christoph; Portilho-Ramos, Rodrigo Costa; Zeng, Jing-Ying; Zhang, Yancheng; Schefuß, Enno; Mollenhauer, Gesine; Hefter, Jens; Alexandre, Felipe; Mulitza, Stefan; Sampaio, Gilvan
The temporal succession of changes in Amazonian hydroclimate during Heinrich Stadial 1 (HS1) (ca. 18-14.7 cal ka BP) is currently poorly resolved. Here we present HS1 records based on isotope, inorganic and organic geochemistry from a marine sediment core influenced by the Amazon River discharge. Our records offer a detailed reconstruction of the changes in Amazonian hydroclimate during HS1, integrated over the basin. We reconstructed surface water hydrography using stable oxygen isotopes (d18O) and Mg/Ca-derived paleotemperatures from the planktonic foraminifera Globigerinoides ruber, as well as salinity changes based on stable hydrogen isotope (dD) of palmitic acid. We also analyzed branched...
Hollstein, Martina; Mohtadi, Mahyar; Rosenthal, Yair; Moffa-Sanchez, Paola; Oppo, Delia W; Martínez-Méndez, Gema; Steinke, Stephan; Hebbeln, Dierk
Mg/Ca and stable oxygen isotope compositions (d18O) of planktic foraminifera tests are commonly used as proxies to reconstruct past ocean conditions including variations in the vertical water column structure. Accurate proxy calibrations require thorough regional studies, since parameters such as calcification depth and temperature of planktic foraminifera depend on local environmental conditions. Here we present radiocarbon-dated, modern surface sediment samples and water column data (temperature, salinity, and seawater d18O) from the Western Pacific Warm Pool. Seawater d18O (d18OSW) and salinity are used to calculate individual regressions for western Pacific surface and thermocline waters (d18OSW = 0.37 × S-12.4 and d18OSW...
Stenegren, Marcus; Caputo, Andrea; Berg, Carlo; Bonnet, Sophie; Foster, Rachel A
Eight different cyanobacterial diazotrophs (Trichodesmium spp., UCYN-A1, UCYN-A2, UCYN-B, UCYN-C, het-1, het-2 and het-3), and two phytoplankton hosts (UCYN-A1 and A2 hosts), were quantified by their nifH genes (18S rRNA for the hosts) in the western tropical South Pacific in spring 2015. The qPCR data was generated at 18 stations along a west to east transect from New Caledonia to Tahiti, covering oligotrophic to ultra-oligotrophic waters.
Stenegren, Marcus; Caputo, Andrea; Berg, Carlo; Bonnet, Sophie; Foster, Rachel A
The abundance and distribution of cyanobacterial diazotrophs were quantified in two regions (Melanesian archipelago, MA; and subtropical gyre, SG) of the western tropical South Pacific using nifH quantitative polymerase chain reaction (qPCR) assays. UCYN-A1 and A2 host populations were quantified using 18S rRNA qPCR assays including one newly developed assay. All phylotypes were detected in the upper photic zone (0-50m), with higher abundances in the MA region. Trichodesmium and UCYN-B dominated and ranged from 2.18 x 10**2 to 9.41 x 10**6 and 1.10 x 10**2 to 2.78 x 10**6 nifH copies L**-1, respectively. Het-1 (symbiont of Rhizosolenia diatoms) was the...
Super, James R; Thomas, Ellen; Pagani, Mark; Huber, Matthew; O'Brien, Charlotte L; Hull, Pincelli M
Climate proxies indicate coupling between changes in atmospheric pCO2, global temperatures and ice volume over much of the Cenozoic. Evidence has been presented for decoupling of these factors in the Miocene, though the cause of the apparent decoupling was uncertain. Here, we revisit Deep Sea Drilling Program (DSDP) Site 608 (24-9 Ma) in the North Atlantic, to provide improved constraints on sea surface temperatures (SSTs) using the TEX86 and Uk'37 proxies, and use these to recalculate atmospheric pCO2. From the Oligocene/Miocene boundary to the middle Miocene Climatic Optimum (MCO, ~23.03 to ~14.5 Ma), SSTs at Site 608 were upwards of...
Joerg, Philip Claudio; Morsdorf, Felix; Zemp, Michael
This dataset contains multi-temporal raster geotiff data of the Findelengletscher, Valais, Switzerland (46° N, 7° 52' E), documenting the glacier change in the period 2005-2010. The data is available in the Swiss datum CH1903 (LV03). Elevations are in meters in the Swiss LN02. The spatial resolution is one meter. The airborne laser scanning (LiDAR) point cloud data was interpolated into a raster grid in Matlab (average of point elevations per grid cell). Empty cells were interpolated using a least squares method without changing known values. Moreover, the extrapolation behavior was linear.
There are four data sets available, from October 28/29, 2005;...
Wu, Henry C; Moreau, Mélanie; Linsley, Braddock K; Schrag, Daniel P; Corrège, Thierry
Sub-seasonally resolved and replicated coral Sr/Ca time series at Clipperton Atoll (10°18'N, 109°13'W) in the eastern Pacific are assessed as a sea surface temperature (SST) proxy in this region with small seasonal SST variability. The composite coral Sr/Ca time series is a partially replicated record of three live and one sub-modern colony of Porites lobata extending back to 1874. Large inter-colony coral Sr/Ca offsets equate to relative SST differences of 0.6 to 4.3 °C and limit the ability to reconstruct absolute SST changes. Moreover, the replication method revealed a 12-year section of growth in one colony where mean Sr/Ca was...
Bi, Rong; Chen, Xi; Zhang, Jing; Ishizaka, Joji; Zhuang, Yanpei; Jin, Haiyan; Zhang, Hailong; Zhao, Meixun
Continental margin ecosystems in the western North Pacific Ocean are subject to strong climate forcing and anthropogenic impacts. To evaluate mechanisms controlling phytoplankton biomass and community structure variations in marginal sea-open ocean boundary regions, brassicasterol, dinosterol and C37 alkenones were measured in suspended particles in summer and autumn from 2012 to 2013 in the northeastern East China Sea and the western Tsushima Strait (NEECS-WTS). In summer, the concentrations of brassicasterol (40 - 1535 ng L-1) and dinosterol (4.2 - 94 ng L-1) were higher in the southwest of Cheju Island, while C37 alkenones (0 - 30 ng L-1) were higher...