Nutrients and chlorophyll from sea water samples collected in the Ross Sea from 2013-2015 (Ross Sea Microb Ecophys project)

<p>Water was pumped to the surface using a trace metal clean diaphragm pump and acid cleaned teflon tubing and dispensed into trace metal clean (TMC) 50 L carboys. Sampling occurred between 18:00 and 19:00 in open air, with wind coming strictly from over open water, NNE to NE.&nbsp; The carboys were protected from light with dark plastic bags and returned to the Crary Laboratory at McMurdo Station via helicopter within one hour of sampling.</p>

<p>Chl <em>a</em> was measured using 90% acetone extracts and the non-acidified fluorometric method, employing a Turner Designs fluorometer and Whatman GF/F filters.</p>

<p>Nitrate (NO₃^-), nitrite (NO₂^-), phosphate (PO₄^3-) and silicate (SiO₄) concentrations were measured in duplicate on a Lachat QuikChem 8500 autoanalyzer.&nbsp; Ammonium (NH₄⁺) concentrations were measured in triplicate using the phenol-hypochlorite method.</p>