Dataset: Hydrothermal vent porewater nutrients - MPI
Deployment: AT42-05

This porewater dataset was obtained at the Max-Planck-Institute for Marine Microbiology in Bremen, Germany. The sampling site names in the data are based on Teske et al. 2016.

For analyses at the Max-Planck Institute for Marine Microbiology (Gunter Wegener), intact sediment cores were sampled using the Rhizons (Rhizosphere Research Products, Wageningen, NL) as described previously (Seeberg-Elversfeldt et al., 2005). The overlying water was removed from the cores and holes were drilled into designated sediment sampling depths. Pretreated Rhizons were injected and suction was applied with syringes for approx. 30 min. The rhizome depths are given in the dataset (depth_bsf).

For sulfide analysis, 1 ml porewater subsamples were fixed with 0.1 ml of 0.1 M zinc acetate solution to preserve the sulfide as zinc sulfide until analysis by the methylene blue method (Cline 1969). The same fixed porewater sample was used for measuring sulfate concentrations using ion chromatography (Metrohm 930 Compact IC flex oven, Metrosep A PCC HC/4.0 preconcentration column, and Metrosep A Supp 5 Guard/4.0 chromatography column).

The concentrations of ammonia, nitrite, nitrate, phosphate, and silicate were determined from porewater using a continuous flow nutrient analyzer (QuAAtro39; Seal Analytical) as published previously (Grasshoff et al., 2009).

Problem report: Transport problems have caused sample losses among the porewater samples, which are evident in occasional gaps in porewater profiles.