Samples for inorganic nutrient analysis were collected in HDPE bottles and frozen (-20\u00baC) immediately after sample collection. Samples were kept frozen until processing by Joe Jennings at Oregon State University. The analyses for phosphate (PO4), nitrate plus nitrite (NO3_NO2), nitrite (NO2), ammonium (NH4), and silicic acid (silicate) were performed using a hybrid Technicon AutoAnalyzerII and Alpkem RFA300 system following protocols modified from Gordon et al. (see below for reference). The estimated precision for each element was as follows: PO4, \u00b1 0.008 \u00b5M; NO3_NO2, \u00b1 0.15 \u00b5M; NO2, \u00b1 0.01 \u00b5M; silicic acid, \u00b1 0.3 \u00b5M.
\n
To obtain the concentration of total organic carbon (TOC) and total nitrogen (TN), a 40 ml aliquot of whole seawater was acidified to pH~3 with concentrated hydrochloric acid (HCl) and stored in combusted glass vials at 4\u00b0C until analysis with a Shimadzu TOC-VCSH total organic carbon analyzer coupled to a TNM-1 analyzer. Blanks (MilliQ water) and standard curves with potassium hydrogen phthalate and potassium nitrate were interspersed into the sample runs. The coefficient of variability between replicate injections was <1%. Comparisons to standards provided by Prof. D. Hansell (University of Miami) were made daily.
\n
References:
\nGordon, L. I., J. C. Jennings, Jr., A. A. Ross, and J. M. Krest. 1994. A suggested protocol for continuous flow automated analysis of seawater nutrients (phosphate, nitrate, nitrite and silicic acid) in the WOCE Hydrographic Program and the Joint Global Ocean Fluxes Study. In WOCE operations manual. WOCE report no. 68/91, revision 1. WHP Office Report WHPO91-1. Woods Hole Oceanographic Institution, Woods Hole, Mass.
Inorganic and organic nutrient data from Niskin bottles from the KN210-04 cruise. Data include concentration of: phosphate, nitrate+nitrite, silicate, nitrite, ammonium, non-purgeable organic carbon, and total nitrogen.
The data have been examined to identify outliers, and no samples were removed from the dataset. There are values in the inorganic nutrient data which are below zero, and these should be considered as below the detection limit for the instrument.
\n
BCO-DMO Processing Notes:
\n- Parameter names were modified to conform with BCO-DMO naming conventions.
\n- lat_start and lon_start were added by joining the data to the event log and matching on the unique event number.
\n- Replaced 'NaN' with 'nd' to indicate 'no data'.
\n- Replaced questionable NPOC value for cast 18, niskin 21 with 'nd' per request of PI (change made on 25 July 2016).