Gradients 5 - TN412 - Nutrients from Underway

These Simons Collaboration on Ocean Processes and Ecology (SCOPE) data products were produced by the University of Hawaiʻi at Mānoa with support from the Simons Foundation. This dataset was collected on the R/V Thompson during the Gradients V cruise which departed from San Diego, CA and ended in Honolulu, HI. A transect was performed on the 140 degree longitude line from roughly 16 degrees N to 4 degrees S before heading to Honolulu. All organic and inorganic nutrients are analyzed in unfiltered seawater that was sampled from the underway uncontaminated seawater system into HDPE or polypropylene bottles and immediately frozen. Silicate, phosphate and nitrate+nitrite are determined colormetrically on a SEAL Analytical Autoanalyzer (AA3 with HR detectors), with the exception of nitrate+nitrite that is <0.5umol/L, which is analyzed by chemiluminescence. Total phosphorus (TP) and total nitrogen (TN) are determined by analysis of phosphate and nitrate, respectively, after oxidation by high-intensity ultraviolet light. Total organic phosphorus and total organic nitrogen are determined by subtracting background PO4 and NO3+NO2 from TP and TN, respectively. Time is in UTC.