ALBERT

Description: In this work we used controlled microcosms to study the effect of temperature and pH on brGDGTs in lake water. We collected surface water from Kennedy Lake, Tucson, AZ, a shallow eutrophic artificial reservoir previously described by Martínez-Sosa & Tierney (2019). From the collected samples we set up a series of microcosms, consisting of 1L glass flasks filled with lake water, and manipulated single environmental factors including temperature and pH. For our temperature incubations, we selected four conditions (9C, 18C, 27C and 35C) and incubated 3 1L flasks under each condition for two periods of time (4 or 6 weeks). For the pH incubations, we used commercially available freshwater aquarium non-phosphate buffers (Proprietary composition, Seachem, Madison, GA, USA) to manipulate the pH of the microcosms. For these experiments we targeted four pH conditions (4, 5, 6 and 7), and included two control samples: one where we added enough buffer to maintain the initial pH (Control + Buffer), and another to which we added no buffer (Control - Buffer). GDGTs were analyzed on an Agilent 1260 Infinity HPLC coupled to an Agilent 6120 single quadrupole mass spectrometer using two BEH HILIC silica columns (2.1 x 150 mm, 1.7 um; Waters) and the methodology of Hopmans et al. (2016). We calculated peak areas using the MATLAB package software ORIGAmI (Fleming et al. 2016) and estimated the concentration of brGDGTs by comparing the obtained peaks with a C46 internal standard (Huguet et al. 2006) normalized to the volume of each sample.

Description: A high-resolution carbonate C-isotope (δ13Ccarb) stratigraphy for the Aptian is presented for the Cau core from Alicante, Spain. The studied succession, lower to upper Aptian, embraces the record of the Early Aptian OAE 1a. The data provided includes δ13Ccarb, δ18O isotopes, Total Organic Carbon (TOC) and CaCO3. Four overlapping cores (D1 to D4) were drilled with an almost 100% recovery of a total (corrected for dip) thickness of 143 m. The cores were split in two parts. One half was described, photographed and scanned, and then sampled with a drill to obtain powdered samples for geochemical analyses. Also, small solid samples were taken from the drill for biostratigraphic characterization of the nannofossil and planktonic foraminifera associations. Second half was stored for archive and future research.

Description: The dataset contains counts of meiofauna organisms on high taxonomic level and predicted distributions computed for overall meiofauna abundance, diversity (Simpson's Index D and Evenness E), richness (ntax) and individual taxa using random forest regressions. Furthermore, a habitatmap is provided, dividing the area based on k-means clustering of combined predicted distributions, bathymetry and backscatter. The spatial layers are saved as grid-files, being the standard format of the R-package "raster" (https://cran.r-project.org/web/packages/raster/index.html). Study area is an area allocated to the German Federal Institute for Geosciences and Natural Resources for the exploration of polymetallic nodule mining. Deep-sea mining highly endangers the benthic communities; hence the definition of preservation zones, not only for preservation but also to enable the re-settlement of mined areas, is highly important. These datasets on the spatial distribution of meiofauna have been used to account for a modelling approach to find areas with similar environmental conditions and similar benthic communities.

Description: The dataset contains predicted distributions computed for overall meiofauna abundance, diversity (Simpson's Index D and Evenness E), richness (ntax) and individual taxa using random forest regressions. Furthermore, a habitatmap is provided, dividing the area based on k-means clustering of combined predicted distributions, bathymetry and backscatter.

Description: The data of two sections studied in the Barremian (Early Cretaceous) of the Subbetic Domain (SE Spain) are shown here together with a detailed log showing the bed number and the biostratigraphic scheme. The samples were collected with a geologist hammer in May 2016. The average sample distance is 0.07 m and was kept as constant as possible using a Jacob's staff to ensure the detection of all the Milankovitch cycles applying Fast Fourier Transforms and related methods (e.g. multi-taper). The lithology is composed of marl-limestone alternations deposited in a (hemi-)pelagic setting. Observed fauna is composed of ammonites, radiolarians, foraminifera, calcareous nannofossils and scarce belemnites, bivalves, gastropods, brachiopods and irregular echinoids. The biostratigraphy scheme is provided in the detailed logs and is based on Tethyan ammonite and calcareous nannofossils. The interval studied of Barranco de Cavila section (38°3'10'' N; 1°53'20'' W) covers from the Late Barremian (Vandenheckii Zone) to the Early Aptian (Forbesi Zone). Carbon and oxygen isotope ratios were measured with a Wahlen VG Prism II mass spectrometer. The mass spectrometer was calibrated with three NBS standards, Nos. 18, 19 and 20

Description: The data of two sections studied in the Barremian (Early Cretaceous) of the Subbetic Domain (SE Spain) are shown here together with a detailed log showing the bed number and the biostratigraphic scheme. The samples were collected with a geologist hammer in May 2016. The average sample distance is 0.07 m and was kept as constant as possible using a Jacob's staff to ensure the detection of all the Milankovitch cycles applying Fast Fourier Transforms and related methods (e.g. multi-taper). The lithology is composed of marl-limestone alternations deposited in a (hemi-)pelagic setting. Observed fauna is composed of ammonites, radiolarians, foraminifera, calcareous nannofossils and scarce belemnites, bivalves, gastropods, brachiopods and irregular echinoids. The biostratigraphy scheme is provided in the detailed logs and is based on Tethyan ammonite and calcareous nannofossils. The two sections studied are Arroyo Gilico section (38°9'35'' N; 1°40'41'' W; the interval studied covers from the Late Hauterivian (Balearis Zone) to the Late Barremian (Vandenheckii Zone)) and Barranco de Cavila section (38°3'10'' N; 1°53'20'' W; the interval studied covers from the Late Barremian (Vandenheckii Zone) to the Early Aptian (Forbesi Zone)).Magnetic susceptibility was measured with a KLY-3 and calcium carbonate content was measured following the volumetric method using the automatic calcimeter Dream Electronique

Description: N2O production rates from ammonium, nitrite and nitrate and nitrate reduction rates and ammonium oxidation rates from the top 400 m water depth off the coast of Peru sampled from R/V Meteor during M138 in June 2017.

Description: Previous paleoceanographic applications of the N isotopes in the eastern equatorial Pacific have used the N isotopic composition of the bulk sediment, which can be biased by diagenetic alteration or foreign N input. To avoid these biases, we measured foraminifera shell-bound d15N (FB-d15N) on the two species Neogloboquadrina dutertrei and Neogloboquadrina incompta in two sediment cores extending back to the last ice age. The datafile contains FB-d15N data measured on the two sediment cores ME0005-24JC (0°1.3' N, 86°27.8' W, 2941m) and ME0005-27JC (1°51.2' S, 82°47.2'W, 2203m) from the eastern equatorial Pacific, as well as updated age models for the two sediment cores. Moreover, it contains estimated changes in Pacific oxygen concentration from the LGM to the Holocene. The age models for both sediment cores have been updated by Dubois et al. (2014) and are based on (1) radiocarbon ages measured on the planktonic foraminifera N. dutertrei by accelerator mass spectrometry, (2) correlation of benthic foraminifera oxygen isotopes to the LR04 stack and (3) the identification of the Los Chocoyos Ash Layer in the sediment cores. In core ME0005-27JC, three additional 14C dates on N. dutertrei from Mekik (2014) were included. All radiocarbon ages were calibrated with Calib 7.1. and the marine calibration curve MARINE13, assuming a reservoir age of 467 years as given in Dubois et al. (2014). Ages were linearly interpolated between the stratigraphic tie points. Foraminifera-bound d15N (FB-d15N) was measured with the “persulfate-denitrifier” technique (Ren et al., 2009; Straub et al., 2013). In short, ~3-5 mg of foraminifera (N. dutertrei and N. incompta from the 300-600µm size fraction) were picked, cut open with a scalpel and underwent a chemical cleaning. The organic N bound within the calcite was then released by dissolution with HCl and converted to nitrate in a basic potassium persulfate solution. The nitrate concentration of the solution was determined by chemiluminescence, and an aliquot of the nitrate solution equivalent to 5nmol of N was converted to nitrous oxide (N2O) by denitrifying bacteria. The N isotopic composition of the N2O was measured with a custom continuous-flow system for N2O extraction and purification on-line to a Thermo MAT253 stable isotope mass spectrometer and referenced to air N2 using the international nitrate standards IAEA-N3 and USGS-34. The FB-d15N data were then corrected for the contribution of the oxidation procedural blank with an in-house aminocaproic acid standard of known isotopic composition. Changes in Pacific oxygen concentration from the LGM to the Holocene were calculated based on solubility changes as well as CYCLOPS box model results of Hain et al., (2010). Changes in oxygen saturation result from changes in temperature and salinity; changes in oxygen utilization result from a glacial shoaling of the Atlantic Meridional Overturning Circulation, enhanced nutrient consumption due to Subantarctic iron fertilization, reduced Antarctic surface-to-deep exchange and more complete Antarctic nutrient consumption. Oxygen utilization is calculated using O2:Pregenerated of -170:1 (Anderson and Sarmiento, 1994).