ALBERT

Beschreibung: A uniform chronology for foraminifera-based sea surface temperature records has been established in more than 120 sediment cores obtained from the equatorial and eastern Atlantic up to the Arctic Ocean. The chronostratigraphy of the last 30,000 years is mainly based on published d18O records and 14C ages from accelerator mass spectrometry, converted into calendar-year ages. The high-precision age control provides the database necessary for the uniform reconstruction of the climate interval of the Last Glacial Maximum within the GLAMAP-2000 project.

Beschreibung: The Tara Oceans Expedition (2009-2013) sampled the world oceans on board a 36 m long schooner, collecting environmental data and organisms from viruses to planktonic metazoans for later analyses using modern sequencing and state-of-the-art imaging technologies. Tara Oceans Data are particularly suited to study the genetic, morphological and functional diversity of plankton. Data sets in this collection provide methodological and environmental context to all samples collected during the Tara Oceans Expedition (2009-2013).

Beschreibung: Coccolithophores -single-celled calcifying phytoplankton- are an important group of marine primary producers and the dominant builders of calcium carbonate globally. Coccolithophores form extensive blooms and increase the density and sinking speed of organic matter via calcium carbonate ballasting. Thereby, they play a key role in the marine carbon cycle. Coccolithophore physiological responses to experimental ocean acidification have ranged from moderate stimulation to substantial decline in growth and calcification rates, combined with enhanced malformation of their calcite platelets. Here we report on a mesocosm experiment conducted in a Norwegian fjord in which we exposed a natural plankton community to a wide range of CO2-induced ocean acidification, to test whether these physiological responses affect the ecological success of coccolithophore populations. Under high-CO2 treatments, Emiliania huxleyi, the most abundant and productive coccolithophore species, declined in population size during the pre-bloom period and lost the ability to form blooms. As a result, particle sinking velocities declined by up to 30% and sedimented organic matter was reduced by up to 25% relative to controls. There were also strong reductions in seawater concentrations of the climate-active compound dimethylsulfide in CO2-enriched mesocosms. We conclude that ocean acidification can lower calcifying phytoplankton productivity, potentially creating a positive feedback to the climate system.

Beschreibung: A biomarker approach is applied on a well-dated core from the Beaufort Sea directly off the Mackenzie River to reconstruct changes in sea ice, sea surface temperature (SST), primary productivity, and terrigenous input. High-resolution records indicate that the southern Beaufort Sea was nearly ice-free in summer during the last deglaciation and early Holocene, and a seasonal sea-ice cover developed during the mid-late Holocene, coinciding with a drop in terrigenous sediment flux and primary production. Superimposed to this climate-driven long-term change in surface-water characteristics, we document two major flood events during the deglacial to Holocene transition. Such major flood events in the Beaufort Sea region may have profound effect on global climate change, especially during times when the massive Laurentide Ice Sheet (LIS) collapsed, and huge amount of freshwater was drained into the Beaufort Sea. This freshening of the Arctic Ocean may have resulted in increased freshwater export into the North Atlantic, causing reduced North Atlantic deep-water formation. The first flood event occurring at ca. 13 kyr BP is related to the Younger Dryas (YD) flood which may have caused severe cooling. The second flood event occurred at ca. 11 kyr BP, whose existence has been hypothesized for a long time but restricted by quality records. Through studies of our sediment core and other records nearby, we hypothesize that the second flood event is more related to shelf flooding induced by strong coastal erosion. 


Beschreibung: The data-sets comes from three locations representative of three different marine ecosystems: Fjord (Chilean Patagonia), Ny-Ålesund (Arctic) and Mediterranean (Crete). It contains chemical and biological data collected in three mesocosm and four microcosm experiments conducted in the spring - summer period, in which the physico-chemical (pH, Carbon) and biological (grazing) conditions were altered to represent potential future climate change scenarios. The data-sets contains measurements in: carbonate chemistry, macro- and micro-nutrients concentrations, primary production, phytoplankton taxonomy, virus abundance, bacterial production, bacterial abundance, Zoo- and microzoo-plankton abundance, grazing rates for different taxonomic groups.

Beschreibung: Here we represent pore water, headspace gas, and TOC data from the four cores recovered from the Chukchi Sea by Jumbo Piston Corer (JPC) during the ARA06C Expedition in 2015 to investigate the origin and diagenesis of pore water and gas. The study cores were retrieved from the Chukchi Sea Shelf (ARA06C-JPC01), the Northwind Basin (ARA06C-JPC02), the East Siberia Continental Slope (ARA06C-JPC03), and the Chukchi Basin (ARA06C-JPC04). We collected pore water from Site ARA06C-JPC01, ARA06C-JPC02, ARA06C-JPC03, and ARA06C-JPC04 and performed compositional and isotopic analyses (e.g. major cation and anions, oxygen, and deuterium isotope, carbon-13 isotope of dissolved carbon, 87Sr/86Sr). The analyzed results of pore water were displayed in the PW Table. The compositional and isotopic data of headspace gas (e.g. methane concentration, and carbon-13 isotope of methane and carbon dioxide) from Site ARA06C-JPC01, ARA06C-JPC02, ARA06C-JPC03, and ARA06C-JPC04 as well as TOC content of bulk sediment from Site ARA06C-JPC01, were represented in the HS Table and TOC Table, respectively.

Beschreibung: These data have been obtained on two cores ARA04C/37 (70°38.0212'N, 139°22.0749'W; 1173 m) and JPC15 (71°06.222'N, 135°08.129'W; 690 m). The datasets contain thermal maturity proxies, specifically of Carbon Preference Index (CPI), fractional abundance of homohopane isomer C31ββR, and Tmax, and OI, HI from the Rock-Eval pyrolysis. Additionally, compound-specific radiocarbon concentrations of bulk organic carbon and long-chain n-alkanoic acids with 26 and 28 carbon atoms have been measured and expressed as F14C with a 1 sigma uncertainty, and counts of Pediastrum spp. An additional dataset contains carbon cycle model simulations using the box model BICYCLE to describe the effect of CO2 release from deglacial terrestrial organic carbon release.

Beschreibung: This collection contains four datasets on (1) chlorophyll a and phaeopigment concentrations, (2) nitrogen and organic carbon contents, (3) sediment oxygen uptakes and benthic boundary fluxes at the sediment-water interface and (4) macrofaunal abundance and biodiversity in sediments in the Canadian Arctic in 2008 and 2009. Data have been produced for a PhD thesis based on samples taken during the following expeditions: - Circumpolar Flaw Lead Study, Legs 9-10 - ArcticNet expedition 2008, Leg 11 (http://www.arcticnet.ulaval.ca/docs/2008_Amundsen_Expedition_Report.pdf) - ArcticNet expedition 2009, Leg 4 (http://www.arcticnet.ulaval.ca/docs/2009_Amundsen_Expedition_Report.pdf) - Malina expedition 2009 (Malina http://malina.obs-vlfr.fr/index.html; http://www.arcticnet.ulaval.ca/docs/2009_Amundsen_Expedition_Report.pdf) In general, sediment retrieved with a giant box corer were used to determine benthic boundary fluxes (oxygen, silicic acid, phosphate, nitrate, ammonium) in incubation chambers, as well as sediment pigment concentration from seperate cores, to study the effect of environmental conditions on benthic ecosystem functions. Parts of the data available in this collection have been analysed for addressing various ecological questions in spatial and temporal context in the publications listed below. A general description of the study region can be found in Link et al. 2013 (POne). Please download the metadata and methods file for more details.

Beschreibung: This dataset contains hydrographical, biogeochemical and bioptical data from four field campaigns to the Mackenzie Delta region from spring to fall in 2019. Focus of the sampling was put on surface waters to compare with satellite imagery and capture the signal of the Mackenzie River water throughout the coastal waters of the Beaufort Sea. The water samples for the biogeochemical data were taken using pumps or niskin bottles. The repeated sampling focused on the two main outflow regions of the Mackenzie River: Shallow Bay and Mackenzie Bay in the west and Kugmallit Bay in the east as well as on the river channels across the delta. Most sampling locations were revisited four times. Sampling during different seasons was extremely challenging in this region due to uncertain ice cover and broken ice fields during and after ice break-up. Additionally, very shallow water (〈5 m) mandates the use of small draught boats, which was challenging under frequently harsh weather conditions. To tackle these challenges, various sampling platforms were used such as small boats, trucks, ski-doos and hovering helicopter. The campaigns were carried out under the umbrella of the EU Horizon 2020 project Nunataryuk.

Beschreibung: The database reports the results of bulk rock geochemical measurements realized on 105 ultramafic lithologies (harzburgites and dunites) samples collected from Holes CM1A (46 samples) and CM2B (59 samples) drilled in the Wadi Tayin massif in the SE of the ophiolite during Phase 2 of the ICDP OmanDP (Nov. 2017-Jan. 2018) (Kelemen et al. [2020]). The studied samples were selected following two strategies. First, a homogeneous sample was selected every 10 m downhole cores during the OmanDP Phase 2 drilling operations, onsite in Oman, in order to get a petrological and geochemical overview continuously along the cores. Second, additional samples have been selected during the daily ChikyuOman Leg 3 sampling meetings in consultation with the core description teams, to focus on more specific facies or levels. These samples are referred to as onsite samples and shipboard samples respectively. Adjacent to each onsite and shipboard sample an oriented thin section billet was taken for mineralogical and lithological characterization. Geochemical data of onsite and shipboard samples were measured both aboard the D/V Chikyu during the ChikyuOman Phase 2 Leg 3 for major element and volatile contents for part of the samples, and at Institute of Earth Science, Academia Sinica, Taiwan (IES-AS), the University of Edinburgh, Scotland (EU), Université Toulouse III - Paul Sabatier, France (TU), and Niigata University, Japan (NU) for trace element contents and additional major element and volatile contents. The purpose of the study was to obtain a high-density and high analytical quality bulk geochemical characterization along continuous cores recovered from OmanDP Holes CM1A and CM2B, from the crust to the mantle through the crust-mantle transition zone. Loss on ignition (LOI) of all onsite and shipboard samples were determined onboard the D/V Chikyu, using the OHTI (Ocean High Technology Institute, Inc., Tokyo, Japan) motion compensated balance system into a pre-weighed ceramic crucible using a spatula (that was never in contact with lithium metaborate flux). Duplicate LOI measurements were done on the onsite samples at EU, following the same steps and procedures. Major element abundances (wt.% oxides) in powdered rock samples were determined using the RIGAKU Supermini wavelength dispersive X-ray fluorescence spectrometer equipped with a 200 W Pd anode tube at 50 kV and 4 mA onboard DV Chikyu during OmanDP Phase 2 Leg 3. Major element analyses were determined to be acceptable if the sum of the anhydrous oxide concentrations totaled to between 99 and 101 wt.%. Precision and accuracy are better than 2.5 % for all oxides except for TiO2 for reference materials DTS-2B and JP-1 (better than 11%) and Na2O, P2O5 and K2O for JGb-2 (3.40, 17.60, and 7.49% respectively). Duplicates of onsite samples whole rock major element analyses were performed at EU, using the Panalytical PW2404 wavelength-dispersive sequential X-ray spectrometer. Gas chromatographic separation was undertaken on non-ignited powders to determine their volatile element contents (total carbon, CTotal and water recalculated from hydrogen) using the Thermo Finnigan™ FlashEA® 1112 elemental analyzers (EA) onboard D/V Chikyu. Whole rock trace element analyses were measured by ICP-MS using acid digestion of powder samples after ChikyuOman 2018 Leg 3. Sample powders were divided into three batches. One batch was sent to each IES-AS, TU and NU laboratory for trace element measurements. The measurements were conducted at IES-AS using an Agilent 7500s inductively coupled plasma‐mass spectrometer (ICP‐MS); at TU using a Thermo Scientific™ Element XR™ HR-ICP-MS; and at NU using Yokogawa HP4500 ICP-MS. To compare the accuracy and the precision in the three different laboratories, trace element measurements were performed on a selection of duplicate samples, and on the same reference materials (DTS-2B and JP-1a).