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Grundwassermessstelle APP_GWMN_17

Dieser Datensatz beschreibt die Grundwassermessstelle APP_GWMN_17 in Schleswig-Holstein. Die Messstelle liegt im Grundwasserkörper EL08 : Stör - Geest und östl. Hügelland. Es liegen insgesamt 25362 Messwerte vor. Es liegen außerdem 35 Probenentnahmen vor (siehe Resourcen).

Grundwassermessstelle APP_GWMN_127

Dieser Datensatz beschreibt die Grundwassermessstelle APP_GWMN_127 in Schleswig-Holstein. Die Messstelle liegt im Grundwasserkörper ST04 : Angeln - östl. Hügelland West. Es liegen insgesamt 38279 Messwerte vor. Es liegen außerdem 11 Probenentnahmen vor (siehe Resourcen).

Grundwassermessstelle APP_GWMN_223

Dieser Datensatz beschreibt die Grundwassermessstelle APP_GWMN_223 in Schleswig-Holstein. Die Messstelle liegt im Grundwasserkörper ST04 : Angeln - östl. Hügelland West. Es liegen insgesamt 50808 Messwerte vor. Es liegen außerdem 2 Probenentnahmen vor (siehe Resourcen).

Grundwassermessstelle APP_GWMN_346

Dieser Datensatz beschreibt die Grundwassermessstelle APP_GWMN_346 in Schleswig-Holstein. Die Messstelle liegt im Grundwasserkörper EI12 : Eider/Treene - östl. Hügelland Ost. Es liegen insgesamt 36693 Messwerte vor. Es liegen außerdem 25 Probenentnahmen vor (siehe Resourcen).

Grundwassermessstelle APP_GWMN_13

Dieser Datensatz beschreibt die Grundwassermessstelle APP_GWMN_13 in Schleswig-Holstein. Die Messstelle liegt im Grundwasserkörper EI20 : Miele - Marschen. Es liegen insgesamt 43630 Messwerte vor. Es liegen außerdem 9 Probenentnahmen vor (siehe Resourcen).

Grundwassermessstelle APP_GWMN_453

Dieser Datensatz beschreibt die Grundwassermessstelle APP_GWMN_453 in Schleswig-Holstein. Die Messstelle liegt im Grundwasserkörper EL13 : Krückau - Altmoränengeest Nord. Es liegen insgesamt 32368 Messwerte vor. Es liegen außerdem 14 Probenentnahmen vor (siehe Resourcen).

Experimental data on enhanced benthic weathering of organic rich Baltic Sea sediments under anoxic to hypoxic conditions

Enhanced mineral dissolution in the benthic environment is currently discussed as a potential technique for ocean alkalinity enhancement (OAE) to reduce atmospheric carbon dioxide (CO2) levels. This study explores how biogeochemical processes affect the dissolution of alkaline minerals in surface sediments during laboratory incubation experiments. These involved introducing dunite and calcite to organic-rich sediments from the Baltic Sea under controlled conditions in an anoxic to hypoxic environment. The sediment cores were incubated with Baltic Sea bottom water. Eight sediment cores were positioned vertically in a rack. Since the sediment surface was slightly oxidized by the bottom water (∼125 μmol l−1 upon recovery), the cores were left plugged on the top for 13 days to settle after recovery until the sediment surface was anoxic. To achieve chemical conditions that are expected in the natural system, 500l of retrieved sea water were degassed via bubbling with pure dinitrogen gas in batches of 100 l. Afterwards, between 50 and 60 l were transferred into an evacuated gas tight bag. After the transfer, pH and total alkalinity (TA) were measured to determine the dissolved inorganic carbon (DIC) of the water. Afterwards the DIC was increased via adding pure CO2 until a CO2 partial pressure (pCO2 ) of ∼2,300–∼3,300 μatm was established mimicking conditions prevailing in Boknis Eck during summer. Stirring heads were installed on the cores. To prevent the development of oxic conditions, it was ensured that as little gas phase as possible was left in the cores. Elimination of pelagic autotrophs, heterotrophs, and suspended particles was achieved by flushing the cores with modified bottom water for 2 days with a flow rate of 1.5 mml min−1. Afterwards, a continuous throughflow of 700 μl min−1 from the reservoir of modified bottom water was applied, leading to a residence time of ∼2.1 days inside the cores. For the experimental incubations, six cores received additions of alkaline materials, three with calcite (Cal1 - Cal3) and three cores with dunite (Dun1 - Dun3), leading to three replicates per treatment. Two control cores remained untreated (C1, C2). The amount of added substrate was based on the rain rate of particulate organic carbon observed in Boknis Eck (0.5 mmol cm−2 a−). The incubation lasted for 25 days. The volume of water in each core was determined at the end of the experiment via measuring the height of the water column after removing the stirring heads. Bottom water samples were taken from the outflow of each core over a time period of several hours. Thus, samples represent the average outflow over the respective time period. Sampling intervals increased from daily during the first two weeks to every three to four days and weekly towards the end of the experiment. All samples were filtered through a 0.2 µm cellulose membrane filter and refrigerated in 25 ml ZinsserTM scintillation vials. A 5 ml aliquot was frozen directly after the sampling procedure for later nutrient analysis. Nutrient measurements were performed either via manual photometric measurement (NH4) or using a Seal – AnalyticalTM QuAAtro autoanalyzer (PO43-). Samples for TA were analyzed directly after sampling by titration of 1 ml of bottom/pore water with 0.02N HCl. Titration was ended when a stable purple color appeared. During titration, the sample was degassed by continuous bubbling with nitrogen to remove any generated CO2 and H2S. The acid was standardized using an IAPSO seawater standard. Acidified sub-samples (30 μl suprapure HNO3- + 3 ml sample) were prepared for analyses of major and trace elements (Si, Na, K, Li, B, Mg, Ca, Sr, Mn, Ni and Fe) by inductively coupled plasma optical emission spectroscopy (ICP-OES, Varian 720-ES). At the end of the experiments, the bottom water was removed via suction and the cores were sliced for pore water analysis. The pore waters were recovered by centrifuging each respective sediment layer in 50 ml falcon tubes at 3000 rpm for 10 minutes. Afterwards, the supernatant water was transferred to polyethylene (PE) vials in an Ar-filled glove bag to minimize contact with oxygen. TA samples (1 ml) were titrated with 0.02N HCl. In addition to the parameters listed above, pore waters were analyzed for H2S and Fe2+. For the analysis of dissolved Fe2+ concentrations, sub-samples of 1 ml were taken within the glove bag, immediately stabilized with ascorbic acid and analyzed within 30 minutes after complexation with 20 μl of Ferrozin. For H2S, an aliquot of pore water was diluted with appropriate amounts of oxygen-free artificial seawater and the H2S was fixed by immediate addition of zinc acetate gelatin solution.

Grundwassermessstelle APP_GWMN_210

Dieser Datensatz beschreibt die Grundwassermessstelle APP_GWMN_210 in Schleswig-Holstein. Die Messstelle liegt im Grundwasserkörper EI14 : Eider/Treene - Geest. Es liegen insgesamt 47925 Messwerte vor. Es liegen außerdem 35 Probenentnahmen vor (siehe Resourcen).

Grundwassermessstelle APP_GWMN_322

Dieser Datensatz beschreibt die Grundwassermessstelle APP_GWMN_322 in Schleswig-Holstein. Die Messstelle liegt im Grundwasserkörper ST03 : Angeln - östl. Hügelland Ost. Es liegen insgesamt 42223 Messwerte vor. Es liegen außerdem 2 Probenentnahmen vor (siehe Resourcen).

Grundwassermessstelle APP_GWMN_353

Dieser Datensatz beschreibt die Grundwassermessstelle APP_GWMN_353 in Schleswig-Holstein. Die Messstelle liegt im Grundwasserkörper EI20 : Miele - Marschen. Es liegen insgesamt 51203 Messwerte vor. Es liegen außerdem 4 Probenentnahmen vor (siehe Resourcen).

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