Gradients2-MGL1704-PP-UW_2020-03-11_v1.0

Cruise: Gradients 2, MGL1704

Project Name: Simons Foundation SCOPE Gradients 2

Description:  The phosphorus content of particulate material (PP) was collected by semi-automated and sequential filtration of the ship’s underway flow through seawater onto acid-washed and combusted GFF filters. Following filtration, filters were placed in histoprep capsules and stored at -80°C for later analysis. Post-cruise, all filters were thawed overnight, combusted at 450°C for 4.5 hours, then extracted with 0.15 M HCl for 1 hour at 60°C. PP was then analyzed spectrophotometrically as SRP in a 1.0 cm cell at 880 nm following Strickland and Parsons (1972). Recovery efficiency was assessed from the analysis of a known dry weight of certified reference material (National Institute of Standards, NIST 1515, apple leaves, certified 0.159% P by weight).  Samples were corrected for a DOP blank placed on the backend of filtrations throughout the duration of the cruise. The ship’s location, sea surface temperature and salinity from ship’s underway instrumentation are matched to the mid-point of each PP filtration time.