Dissolved nitrite and ammonium concentration data from R/V Atlantis (AT15-61) cruise in Jan-Feb 2010 and R/V Melville (MV1104) cruise in Mar-Apr 2011 in the Eastern Tropical South Pacific (NCEI Accession 0278454)

This dataset contains chemical data collected on R/V Atlantis and R/V Melville during cruises AT15-61 and MV1104 in the South Pacific Ocean from 2010-01-31 to 2011-04-18. These data include Ammonium, Nitrite, and depth. The instruments used to collect these data include CTD Sea-Bird 9, Niskin bottle, and Turner Designs Aquafluor 8000. These data were collected by Angela N. Knapp of Florida State University and Karen L. Casciotti of Woods Hole Oceanographic Institution as part of the "Expression of Microbial Nitrification in the Stable Isotopic Systematics of Oceanic Nitrite and Nitrate (Microbial Nitrification)" project. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) submitted these data to NCEI on 2021-05-07.

The following is the text of the dataset description provided by BCO-DMO:

ETSP nitrite (NO2) and ammonium (NH4) concentration data

Dataset Description:
Acquisition Description:
Seawater samples were obtained during the R/V Atlantis (AT15-61) and R/V Melville (MV1104) cruises in Jan-Feb 2010 and Mar-Apr 2011. Water samples were collected at discrete depths using a standard 24-bottle Niskin rosette sampler equipped with an SBE9plus conductivity-temperature-depth (CTD) sensor package (SeaBird Electronics, Bellevue, WA).

Ammonium concentration ([NH 4 + ]) was determined on-ship in unfiltered 50 mL seawater samples using o -phthaldialdehyde derivatization (Holmes et al. , 1999) and measurement on an Aquafluor 8000 handheld fluorometer (Turner Designs), with modifications as suggested in Taylor et al. , 2007. Nitrite ([NO 2 - ]) was determined on-ship in unfiltered 50 mL sample volumes using standard colorimetric methods (Strickland and Parsons, 1968). NH 4 + standards (30 – 300 nM) were freshly prepared for each analysis in duplicate using deep water (> 500 m) from the same station, which consistently had a lower blank than ultrapure water. Detection limits for [NH 4 + ] and [NO 2 - ] were 0.010 µM, and 0.10 µM for [NO 2 - ]. Measured values are reported even if they are lower than the detection limit.