ALBERT

Description: Research expeditions are extreme situations in which a group of people is at sea for an extended period of time, working under high pressure to achieve their goals and, often under strenuous conditions. Moreover, many expeditions are characterized by small group sizes, reduced privacy due to spatial restrictions, stronger dependencies among colleagues, and less options to keep physical distance from one another. These circumstances may increase the possibility of unintentional and intentional sexual harassment on expeditions. However, GEOMAR does not tolerate any sexual misconduct and will follow up every formal report of incidents. GEOMAR protects all employees by taking appropriate preventive measures. An initiative of German seagoing institutes and BRIESE Research.

Description: Slides of a presentation of the Elements MAMS created in the context of a DataHub presentation at GFZ. The Elements environment is a Media Asset Management System (MAMS) and consists of hardware and software components. It is a commercial product and has been chosen as the infrastructure for FAIR marine images at GEOMAR, AWI and Hereon.

Description: Highlights • next to organic matter degradation, bioirrigation and bottom water percolation through permeable surface sediments enhances benthic TPO43- and Fe2+ release • changes in bottom water oxygenation induce slight changes benthic TPO43- and Fe2+ release rates measured in 2011 and 2014 • deoxygenation experiments imply enhanced TPO43- and Fe2+ release at ongoing deoxygenation in the Mauritanian OMZ Abstract Benthic fluxes of total dissolved phosphate (TPO43-), dissolved iron (Fe2+), and dissolved inorganic carbon (DIC) were determined in situ using benthic chambers at nine stations along a depth transect between 47 and 1108 m water depth at 18 °N off Mauritania (NW Africa) during the upwelling season in 2014 (RV Meteor cruise M107). Bottom water oxygen (O2) concentrations were always ≥ 25 µM, and all fluxes (TPO43-, Fe2+, DIC) were consistently directed from the sediments into the bottom water. The highest benthic TPO43- release of 0.2 ± 0.07 mmol m2 d-1 was found at 47 m water depth (50 µM O2). The highest diffusive Fe2+ flux of 0.03 mmol m2 d-1, determined from porewater Fe2+ concentrations, occurred at 67 m water depth (27 µM O2). This was much lower than the detrital Fe supply as indicated by constant Fe/Al ratios along the depth transect. TPO43- release rates decreased concurrently with DIC flux and water depth. A difference of up to one order of magnitude between benthic chamber and diffusive TPO43- fluxes indicated that the total TPO43- release was strongly enhanced by bioirrigation. The observed fluxes were similar to those measured during an earlier cruise in 2011, generally indicating comparable release rates during both upwelling seasons. Furthermore, ex situ oxygen manipulation experiments showed an increase of the nutrient release (e.g. TPO43-, Fe2+) after seven days of anoxic bottom water conditions. The fluxes were enhanced by a factor of 1.4 for P and 7.3 for Fe compared to the measured release under natural conditions and reached values as high as those measured in the anoxic oxygen minimum zone off Peru. Our observations support the hypothesis that increasing deoxygenation of the oceans will likely enhance sedimentary TPO43- and Fe2+ release and thus contribute to a positive feedback mechanism with increasing nutrient levels and increased ocean productivity.

Description: Slides of a presentation on the DAM/DataHub portal and viewer for the Digital Science Monday seminar series at GEOMAR. The talk amied to give an overview of the background and functions of the DAM/DataHub portal and viewer from AWI, GEOMAR and Hereon. The DAM/DataHub portal and viewer (marine-data.de) is a centralized access point to search and explore marine data harvested from different national data repositories (e.g. Pangaea, OceanRep, HCDC, etc.).

Description: "Für ein gutes Miteinander auf See“ ist eine Initiative am GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, die sich der Prävention von sexualisierter Belästigung, Diskriminierung und Gewalt (SBDG) auf deutschen Forschungsschiffen widmet. Geleitet wird die Initiative vom Gleichstellungsteam, das in der komplexen Organisationsstruktur der Forschungsschifffahrt viele Akteur*innen zusammenbringen muss, um die Maßnahmen passgenau zu entwickeln und zu etablieren. Auf Forschungsfahrten sind die Menschen für einen längeren Zeitraum auf engem Raum zusammen und können unerwünschten Situationen nicht ausweichen. Das Ziel der Initiative ist es, dafür eine Rettungsinsel zu bieten: Etablierte und klare Strukturen sollen Sicherheit geben und eine Klärung von unerwünschten Situationen ermöglichen. Dieser Beitrag gibt einen Einblick in die Vorgehensweise der Entwicklung der Initiative und erläutert, welche Herausforderungen Forschungsschiffe als Arbeitsort für eine SBDG-Initiative darstellen.

Description: Benthic nitrogen cycling in the Mauritanian upwelling region (NW Africa) was studied in June 2014 from the shelf to the upper slope where minimum bottom water O 2 concentrations of 25 µM were recorded. Benthic incubation chambers were deployed at 9 stations to measure fluxes of O 2 , dissolved inorganic carbon (DIC) and nutrients (NO 3 - , NO 2 - , NH 4 + , PO 4 3- , H 4 SiO 4 ) along with the N and O isotopic composition of nitrate (δ 15 N-NO 3 - and δ 18 O-NO 3 - ) and ammonium (δ 15 N-NH 4 + ). O 2 and DIC fluxes were similar to those measured during a previous campaign in 2011 whereas NH 4 + and PO 4 3- fluxes on the shelf were 2 – 3 times higher and possibly linked to a long-term decline in bottom water O 2 concentrations. The mean isotopic fractionation of NO 3 - uptake on the margin, inferred from the loss of NO 3 - inside the chambers, was 1.5 ± 0.4 ‰ for 15/14 N ( 15 ϵ app ) and 2.0 ± 0.5 ‰ for 18/16 O ( 18 ϵ app ). The mean 18 ϵ app : 15 ϵ app ratio on the shelf (〈 100 m) was 2.1 ± 0.3, and higher than the value of 1 expected for microbial NO 3 - reduction. The 15 ϵ app are similar to previously reported isotope effects for NO 3 - respiration in marine sediments but lower than determined in 2011 at a same site on the shelf. The sediments were also a source of 15 N-enriched NH 4 + (9.0 ± 0.7 ‰). A numerical model tuned to the benthic flux data and that specifically accounts for the efflux of 15 N-enriched NH 4 + from the seafloor, predicted a net benthic isotope effect of N loss ( 15 ϵ sed ) of 3.6 ‰; far above the more widely considered value of ~0‰. This result is further evidence that the assumption of a universally low or negligible benthic N isotope effect is not applicable to oxygen-deficient settings. The model further suggests that 18 ϵ app : 15 ϵ app trajectories > 1 in the benthic chambers are most likely due to aerobic ammonium oxidation and nitrite oxidation in surface sediments rather than anammox, in agreement with published observations in the water column of oxygen deficient regions.

Description: An extensive data set of biogenic silica (BSi) fluxes is presented for the Peruvian oxygen minimum zone (OMZ) at 11ºS and 12ºS. Each transect extends from the shelf to the upper slope (∼1000 m) and dissects the permanently anoxic waters between ∼200 – 500m water depth. BSi burial (2100 mmol m‐2 yr‐1) and recycling fluxes (3300 mmol m‐2 yr‐1) were highest on the shelf with mean preservation efficiencies (34±15%) that exceed the global mean of 10 – 20%. BSi preservation was highest on the inner shelf (up to 56%), decreasing to 7% and 12% under anoxic waters and below the OMZ, respectively. The data suggest that the main control on BSi preservation is the rate at which reactive BSi is transported away from undersaturated surface sediments by burial and bioturbation to the underlying saturated sediment layers where BSi dissolution is thermodynamically and/or kinetically inhibited. BSi burial across the entire Peruvian margin between 3ºS to 15ºS and down to 1000m water depth is estimated to be 0.1 – 0.2 Tmol yr‐1; equivalent to 2 – 7% of total burial on continental margins. Existing global data permit a simple relationship between BSi rain rate to the seafloor and the accumulation of unaltered BSi, giving the possibility to reconstruct rain rates and primary production from the sediment archive in addition to benthic Si turnover in global models.