ALBERT

Description: We investigated the spatio-temporal trajectories of mountain agro-ecosystems by studying five lakes located between 880 and 2440 m a.s.l. in the north-western Alps. More specifically, we were interested in past interactions between agropastoral activities, plant community composition and erosion dynamics. To investigate this question, we relied on a multi-proxy dataset of lake sediment analyses. The selected proxies come mainly from plant and mammal sedimentary DNA analyses, but also from pollen and spore analyses of coprophilous fungi (Sporormiella sp.). The originality of this dataset is the creation of an index of (agro-)pastoral activity intensity valid for each lake catchment. This index showed a pattern of development of (agro-)pastoral activities according to altitude in this Alpine region. This index was then used to analyse the impact of (agro)pastoral activities on erosion dynamics and plant cover.

Description: This data set consists of in-situ measurements carried out aboard the Polar 6 research aircraft during HALO-AC3 campaign in March/April 2022. This comprises the aerosol properties of arctic ambient aerosol particle (outside cloud) and cloud particle residual (inside cloud) and the cloud water content / water vapor. The measurements were carried out north-west and west of Svalbard using the CVI inlet together with the PSAP, CPC, UHSAS aerosol instruments and the WVSS-II hygrometer of the Leibniz Institute for Tropospheric Research (TROPOS) in Leipzig, Germany.

Description: The Pliocene Epoch (~2.6–5.3 million years ago, Ma) was characterized by a warmer than present climate with smaller Northern Hemisphere ice sheets, and therefore offers an example of a climate system in long-term equilibrium with current or predicted near-future carbon dioxide concentrations. The end of the Pliocene (~2.6 Ma) is marked by further ice-sheet expansion and intensification of glacial (cold) stages, referred to as the "intensification of Northern Hemisphere Glaciation" (iNHG). Here we present the data used to assess the spatial and temporal variability of ocean temperatures and ice-volume indicators through the late Pliocene and early Pleistocene (from 3.3 to 2.4 Ma) to determine the character of this climate transition. The data come from the Atlantic, Pacific, Indian and Southern Ocean, as well as some marginal seas. Here we present the synthesized alkenone sea-surface temperature, Mg/Ca sea-surface temperature, planktonic foraminifera d18O and benthic foraminifera d18O data which were used in our synthesis. Although the original data sets are largely published, here we present the alkenone SST records calculated using the BAYSPLINE calibration where these were not part of the original publication; the Mg/Ca-SST records where we revised the absolute SSTs; any data sets where we revised the age model.

Description: The data file contains measured environmental concentrations of organic micropollutants in European streams and additional hydrological parameters (stream order, urban discharge fraction) of the investigated sites. A total of 445 surface water samples were collected during various sampling campaigns between 2016 and 2019. Chemical target screening of 610 compounds by liquid chromatography high-resolution mass spectrometry (LC-HRMS) resulted in 504 detected compounds. The measured environmental concentrations of the detected compounds ranged from 1 ng/L to 74 µg/L (3-cyclohexyl-1,1-dimethylurea). Detection frequencies ranged from one site (0.2 %) to 339 sites (76 %). More information can be found in Finckh and Carmona et al. (2024) DOI: 10.1016/j.envint.2023.108371. The main objective of this study was to quantify and characterise chemical footprints in European streams.

Description: Nd, oxygen isotopes and Mg/Ca ratio measured on foraminifera from sediments issue of core ODP 762. Nd and Sr measurements measured on the detrital fraction of sediment issue of core ODP 762. The data covered the last 500 Kyrs of climatic and oceanographic history of the east tropical Indian Ocean. The oxygen isotopes and Mg/Ca aims to reconstruct the paleotemperature and paleosalinity of the site over the glacial/interglacial oscillation of the last 500 Kyrs. The Nd isotopes measured on carbonate reconstruct the circulation pattern at intermediate depth (1360 mbsl) over the same time period. the isotopic measurements done on the detrital components of the sediments aim to identify the origin of the regional continental inputs.

Description: In order to understand the hydrothermal input of barium (Ba) to the ocean interior and the changes of Ba in the hydrothermal plume, we measured dissolved (〈0.2 μm) and particulate (〉0.2 μm) Ba concentrations, as well as stable isotopes, in the non-buoyant hydrothermal plume at the Rainbow hydrothermal vent field on the Mid-Atlantic Ridge. Samples were taken during a GEOTRACES compliant cruise (M176/2) onboard the German R/V Meteor from September to October 2021. Particulate samples were first leached to measure labile components and then digested to measure refractory components. Our investigation covered the plume with a high spatial resolution, extending from a distance of 200 m to 60 km away from the Rainbow hydrothermal vent field.

Description: This data is part of the BMBF project CUSCO (Coastal Upwelling Systems in a Changing Ocean). Here we report particulate organic matter concentrations collected during a 35-day experiment where we enclosed natural plankton communities in in-situ mesocosms off Peru. The experiment investigated the interactive effects of light and upwelling on the Humboldt upwelling ecosystem by mimicking a gradient of upwelling intensities (0%, 15%, 30%, 45% and 60%) under summer-time high light and winter-time low light. Integrated seawater samples from a depth between 0 and 10m were collected using a 5L Integrating Water sampler (IWS; Hydro-Bios, Kiel). Samples (150-1000 ml) were filtered onto a 0.7 µm pre-combusted glass-fiber filters (GFF, Whatman). The filters were acidified and then dried in the oven at 60 °C for 24 hours and total particulate carbon (TPC), particulate organic carbon (POC) and nitrogen (PON) content were measured using a CN analyzer (Euro EA3000, HEKAtech GmbH, Wegberg, Germany). POP filters were autoclaved for 30 min in 100 mL Schott Duran glass bottles using an oxidizing decomposition solution (Merck, catalogue no. 112936) to convert organic phosphate to orthophosphate. Phosphate concentrations were determined spectrophotometrically following Hansen and Koroleff (1999; doi:10.1002/9783527613984.ch10).

Description: This data is part of the BMBF project CUSCO (Coastal Upwelling Systems in a Changing Ocean). Here we report pigment concentrations and the phytoplankton community composition based on CHEMTAX analysis during a 35-day experiment, where we enclosed natural plankton communities in in-situ mesocosms off Peru. The experiment investigated the interactive effects of light and upwelling on the Humboldt upwelling ecosystem by mimicking a gradient of upwelling intensities (0%, 15%, 30%, 45% and 60%) under summer-time high light and winter-time low light. Integrated seawater samples from a depth between 0 and 10m were collected using a 5L Integrating Water sampler (IWS; Hydro-Bios, Kiel). To obtain pigment concentrations 0.15 – 1L of water sampled from the water column were filtered onto glass-fiber filters (precombusted at 450°C for 6h, GFF, 0.7 µm nominal pore size, Whatman) using a low vacuum of 200 mbar. Afterwards the filters were stored in cryovials at -80°C until analysis of photosynthetic pigments using reverse-phase high-performance liquid chromatography (HPLC) following (Barlow et al., 1997; doi:10.3354/meps161303) as described by (Paul et al., 2015; doi:10.5194/bg-19-5911-2022). The phytoplankton community composition was calculated with CHEMTAX, which classifies phytoplankton taxa based upon taxon-specific pigment ratios (Mackey et al., 1996; doi:10.3354/meps144265). The values for the Peruvian upwelling system determined by (DiTullio et al., 2005; doi:10.4319/LO.2005.50.6.1887) as described by (Meyer et al., 2017; doi:10.3389/fmars.2017.00001) were used as pigment ratios. As phytoplankton microscopy revealed high abundances of the raphydophite Fibrocapsa japonica, the initial pigment matrix was complemented by ratios for F. japonica from (Laza-Martinez et al., 2007; doi:10.1093/plankt/fbm069) from the Atlantic.

Description: Data presented here are trace-elements and boron isotope composition of planktic foraminifera G. ruber (250-355 μm) along with reconstructed surface ocean temperature, salinity, pH and pCO2 for the past 136 Ka from the south-eastern Arabian Sea. Foraminifera cleaning was carried out using the method adopted from Barker et al. 2003. Boron was purified using the micro-distillation method (Misra et al., 2014a). Trace-element analysis (e.g. Mg/Ca) was carried out using the High-Resolution Inductively Coupled Plasma Mass Spectrometer (HR-ICPMS) (Misra et al., 2014b). Boron isotope analysis was carried out using Thermo Neptune Plus multi-collector inductively coupled plasma mass spectrometer (MC–ICPMS), following the method described in Tarique et al. 2021, and Lloyd et al. 2018. Sea surface temperature (SST) was calculated using the foraminifera Mg/Ca utilizing the method adapted from Gray and Evans 2019. Sea surface salinity (SSS) was calculated using the Mg/Ca derived SST, foraminifera d18O and regional seawater d18O and salinity relationship.

Description: During the HALO-(AC)³ field campaign in spring 2022, the Basler BT-67 research aircraft Polar 6, based in Spitzbergen (78.24 N, 15.49 E), was equipped with an advanced in situ cloud payload by the DLR. This payload contained a combination of cloud instruments, including the Cloud Droplet Probe (CDP), the Cloud Imaging Probe (CIP), and the Precipitation Imaging Probe (PIP). The published data contain the particle size distributions measured by each particle measurement system. The respective instruments operate in different size ranges, and by combining their data, an additional data set is calculated that covers cloud particles in the size range from 2.8 µm to 6400 µm. Microphysical cloud properties such as cloud particle number concentration, liquid water content, ice water content, and effective diameter are derived from the given particle size distributions. The in situ cloud measurements focused on low and mid-level clouds in the Fram Strait, over the sea ice and the open ocean. The measurement campaign is embedded in the Transregional Collaborative Research Centre TR 172 (ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)³).