Dissolved ammonium measurements of marine sediment from Long Core Expedition KN195-03

The KN195-03 research cruise on board the R/V Knorr (Chief scientist Steven D’Hondt) took place in January-February 2009 and had as primary objective to test and refine quantitative models for the magnitude and geographic distribution of subseafloor biomass and organic-fueled subseafloor respiration. Sediment cores were taken at thirteen sites across the equatorial Pacific and the North Pacific Gyre. Knowledge of the chemical composition of the porewater throughout the collected cores is fundamental to answer the driving research questions of this scientific expedition. The shipboard geochemistry laboratory generated interstitial waters by squeezing 597 individual samples, and by extracting an additional 153 solutions by Rhizon sampling. Due to the time needed to analyze this very high number of samples, not all were analyzed for each dissolved constituent. We present here the shipboard porewater ammonium concentration dataset measured by colorimetry.