Dataset: Soluble iron (Fe) passed through 10 kDa cross-flow filter, from R/V Knorr cruise KN199-04 in the Subtropical northern Atlantic Ocean in 2010 (U.S. GEOTRACES NAT project)

Soluble iron (Fe), the Fe passing through a 10 kDa cross-flow filtration membrane, is reported in nmol Fe per kg of seawater. Samples were collected on the U.S. GEOTRACES North Atlantic Zonal Transect, Leg 1, in 2010.

In comparing this data to other published profiles of soluble Fe, it is valuable to know that soluble Fe is a highly operationally-defined parameter. The two most common methods of collecting soluble Fe samples are via 0.02 µm Anopore membrane filtration and by cross-flow filtration (this study). An intercalibration between the two methods used to collect soluble Fe samples on the U.S. Atlantic GEOTRACES cruises are described in this excerpt (PDF) from a Fitzsimmons manuscript (in preparation). The intercalibration determined that "soluble Fe produced by cross-flow filtration (10 kDa membrane) is only ~65-70% of the soluble Fe produced by Anopore filtration."

Please note that some US GEOTRACES data may not be final, pending intercalibration results and further analysis. If you are interested in following changes to US GEOTRACES NAT data, there is an RSS feed available via the BCO-DMO US GEOTRACES project page (scroll down and expand the "Datasets" section).