Dataset: SAFe and GEOTRACES trace element references from R/V Knorr KN199-04, KN204-01 in the Subtropical northern Atlantic Ocean from 2010-2011 (U.S. GEOTRACES NAT project)

SAFe reference samples:
During the SAFe (Sampling and Analysis of Fe) program and the North Atlantic and North Pacific GEOTRACES Intercalibration cruises, we (Geoffrey Smith and Ken Bruland) collected large volumes of homogenized surface and deep seawater to provide 0.5 L SAFe reference samples to researchers investigating the marine chemistry of trace metals in both the U.S. and international trace metal communities. Surface seawater was collected using the UCSC designed "GeoFish" towed sampling system, filtered as described below and then homogenized in two 500 L SAFe tanks. Water from 1000 m was collected with multiple four-bottle casts using our Teflon coated, 30 L, GOFlo samplers deployed on Kevlar hydroline (Bruland et al. 1979), filtered and then homogenized in one of the SAFe tanks. Our GeoFish/SAFe tank system consists of PFA Teflon tubing, an all PFA Teflon diaphragm pump, sequential filtration through 0.45 µm then 0.2 µm pore size polycarbonate, track etched (PCTE) pleated filter cartridges and two 500 L fluorinated low density polyethylene tanks connected with all Teflon tubing, valves and fittings. All filtrations, acidifications and bottling of the SAFe samples were performed inside of Class-100 clean benches in a portable clean van. We successfully collected and continue to provide to an international trace metal community 650 SAFe S reference samples of surface water, 650 SAFe D1 reference samples of 1000 meter depth water, and 650 SAFe D2 reference samples of 1000 meter depth water. These samples have been stored in rigorously acid cleaned LDPE bottles for over four years and have proven stable for dissolved Fe and other trace metals. These SAFe reference samples are now proving to be valuable for a suite of GEOTRACES key and non-key trace metals.

GEOTRACES reference samples:
A variety of GEOTRACES reference samples are also available. We used the SAFe tank system on the North Atlantic GEOTRACES Intercalibration cruise to collect an additional set of North Atlantic GEOTRACES reference samples from the surface and from a depth of 2000 meters. The surface reference sample (GS) was collected with the GeoFish sampling system in the same manner as for SAFe S samples, while the 2000 m deep reference sample (GD) was collected with 5 separate casts of the GEOTRACES rosette to rinse and fill a tank.

During the Pacific GEOTRACES Intercalibration cruise, we used the GeoFish/SAFe tank system to collect additional Pacific surface water from the SAFe site to be used as GEOTRACES surface Pacific (GSP) reference samples (~300 0.5 L bottles). Additionally, we collected a surface tank from the highly productive surface waters of the Santa Barbara Basin coastal site on the Pacific Intercalibration cruise and aliquoted ~600 0.5 L samples of this water as a SAFe/GEOTRACES coastal surface reference sample, "SGC".