(Table 1) Sr and S isotope compositions of marine barites from ODP Hole 123-765C

Barite can precipitate in microenvironments in the water column (marine barite), from supersaturated pore fluids at the oxic-anoxic boundary within marine sediments and where Ba-rich pore fluids are expelled and come into contact with sulfate-rich seawater (diagenetic barite), or from hydrothermal solutions (hydrothermal barite). Barite is relatively resistant to alteration after burial and has been used in paleoceanographic studies to reconstruct seawater chemistry and productivity through time. For such applications it is very important to determine the origin of the barite used, because both diagenetic and hydrothermal barite deposits may not accurately record the open-ocean contemporaneous seawater chemistry and productivity. We show here that it is possible to distinguish between the different types of barite by using Sr and S isotopes along with crystal morphology and size characteristics.

Biogenic and environmental fluctuations of temperature and pH in a novel mesocosm concept ("Kiel Outdoor Benthocosms") April 2013 to September 2014

The Kiel Outdoor Benthocosm infrastructure (Kiel, Germany,N 54°19.8'; E 010°09.0') allows combining natural in-situ fluctuations on all environmental variables with the controlled manipulation of treatment factors. The environmental fluctuations are admitted by a continuous flow-through of fjord water. The treatment is applied by delta-treatments which shift the mean of target variables (temperature and pH in this case) while maintaining the frequency and amplitude of natural fluctuations. The data presented here show the treatment levels and the continuously logged temperature and pH conditions in the experimental tanks. The dynamics of temperature and pH are driven by (i) in situ variability, (ii) the treatments imposed and (iii) the biology of the biota in the tanks. These contained macroalgal communities with associated mesograzers, mussels, and sea stars. The data set comprised 5 experimental runs: spring experiment (4.4.-19.6.2013), summer experiment 1 (4.7.-17.9.2013), autumn experiment (10.10-17.12.2013), winter experiment (16.1. - 1.4.2014), summer experiment 2 (10.7. - 26.9.2014).