Nitrogen concentration and δ15N of altered oceanic crust obtained on ODP Legs 129 and 185: Insights into alteration-related nitrogen enrichment and the nitrogen subduction budget

Ammonium stability and nitrogen isotope fractionations for –NH3(aq)–NH3(gas) systems at 20–70°C and pH of 2–13: Applications to habitability and nitrogen cycling in low-temperature hydrothermal systems

“…Even so, the strongly convective hydrothermal environments may still induce the escape of aqueous ammonia from the high-pH fluid along the concentration gradient in the Lost City hydrothermal system. This is quite different from the hydrothermal systems in the Phanerozoic terrestrial (e.g., the Yellowstone hot springs; Holloway et al, 2011) and forearc environments (e.g., the Mariana mud volcanoes; Salisbury et al, 2002) where large nitrogen reservoirs exist in sediments/sedimentary rocks and in clay minerals with possible contributions from assimilation of organic nitrogen and nitrogen reduction process (Li et al, 2007;Holm and Neubeck, 2009). Oceanic hydrothermal systems have little contribution from sedimentary nitrogen except in a very few cases (e.g., Karl et al, 1988;Lilley et al, 1993).…”

Nitrogen-enhanced greenhouse warming on early Earth

“…We estimate the contemporary net nitrogen flux into the mantle as subduction input minus arc volcanic output. Subduction inputs consist of sediments 22 25 . Although AOC is a small (but perhaps preferentially preserved 25 ) part of the nitrogen subduction budget at present, we envisage that it would have had a much larger role under both anoxic and fast spreading rate conditions.…”

N2, Ar, and He as a tool for discriminating sources of volcanic fluids with application to Vulcano, Italy

“…However, Hilton et al (2002) argued against subducting sediments transporting He into the mantle based on the high mobility of He. Nitrogen in oceanic sediments and altered crust was analyzed by Sadofsky and Bebout (2004), Li and Bebout (2005), and Li et al (2007). The 1σ uncertainties are given very approximately, to give an idea about the natural scatter of data.…”