Geochemistry of coastal sites affected by submarine groundwater discharge along the Puck Bay, southern Baltic Sea

This study aimed to characterize the composition of submarine groundwater discharge at the shoreline of the Puck Bay, southern Baltic Sea. Porewater was sampled at various depths down to 50 cm using push point lances with PE syringes and filtered (0.45 µM, disposable cellulose acetate filters) for analysis of for major and trace metals and selected nutrients by ICP-OES (iCAP, 7400, Duo Thermo Fischer Scientific), dissolved ammonium (NH4+) by QuAAtro Analyzer System, total sulphide with a Specord 40 spectrophotometer (Analytik Jena), dissolved inorganic carbon (DIC) and δ13CDIC with an isotope gas mass spectrometer (MAT 253) coupled to a Gasbench II, and δ18OH2O, and δ2HH2O with a CRDS system (laser cavity-ring-down-spectroscopy, Picarro L2140- I). For radium (Ra) isotopes, 5-10 liters of porewater were transferred into canisters without filtration using a peristaltic pump and filtered through a Mn fiber to extract the Ra. The Ra isotopes (224Ra, 223Ra) were measured within 3 and 10 days using radium delayed coincidence counters (RaDeCC). In addition, seepage meters were used to measure seepage water fluxes and to collect samples for the above-mentioned analyses. Sediment cores were taken, sliced at 2 to 4 cm resolution and analyzed for contents of total carbon, nitrogen, and sulphur using an Elemental Analyzer (Euro Vector EuroEA 3, 052), inorganic carbon using an Elemental Analyzer multi EA (Analytik Jena), and total mercury using a DMA-80 analyzer.

本研究旨在表征波罗的海南部波克湾（Puck Bay）岸线的海底地下水排泄组成。研究采用搭载聚乙烯（PE）注射器的尖头推入式采样杆，采集深度可达50 cm的孔隙水样品；样品经0.45 µm一次性醋酸纤维素滤膜过滤后，采用电感耦合等离子体发射光谱仪（ICP-OES，iCAP 7400 Duo，赛默飞世尔科技（Thermo Fischer Scientific））分析常量与微量金属及目标营养盐，采用QuAAtro分析仪系统测定溶解态铵（NH4+），采用Specord 40分光光度计（Analytik Jena）测定总硫化物，采用与Gasbench II联用的MAT 253同位素气体质谱仪测定溶解无机碳（DIC）及δ13CDIC，采用激光腔衰荡光谱（CRDS，laser cavity-ring-down-spectroscopy）系统（Picarro L2140-I）测定δ18OH2O与δ2HH2O。针对镭（Ra）同位素分析，取5~10升孔隙水通过蠕动泵（peristaltic pump）转移至采样罐中，无需预先过滤，随后经锰纤维滤柱（Mn fiber）富集镭同位素。镭同位素（224Ra、223Ra）分别在采样后3天和10天内，采用镭延迟符合计数器（RaDeCC，radium delayed coincidence counters）完成活度测定。此外，本研究采用渗流仪（seepage meters）测量渗流水通量，并采集渗流水样用于前述各项分析。同时采集沉积物岩心（sediment cores），以2~4 cm为间隔进行切片，采用Euro Vector EuroEA 3052元素分析仪（Elemental Analyzer）测定总碳、总氮及总硫含量，采用Analytik Jena multi EA元素分析仪测定无机碳含量，采用DMA-80测汞仪（DMA-80 analyzer）测定总汞含量。