Gradients 4 - TN397 - Inorganic and Organic Nutrients and Particulates

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 4 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 unflitered seawater that is sampled aboard from the CTD rosette 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 dissolved phosphorus (TDP) and total dissolved nitrogen (TDN) are determined by analysis of phosphate and nitrate, respectively, after oxidation by high-intensity ultraviolet light. Dissolved organic phosphorus and dissolved organic nitrogen are determined by subtracting background PO4 and NO3+NO2+NH4 from TDP and TDN, respectively. Note, because samples are not filtered particulates may comprise a minor portion of totals. Time is in UTC. Details on the methods for particulates (PC, PN, PP, PATP) are available at: https://hahana.soest.hawaii.edu/hot/methods/results.html.