Notes on the Sampling Methodology, by Hugh Ducklow

  Samples were harvested from hydrocasts into Milli-Q and sample-rinsed
  2-liter polycarbonate bottles, and concentrated over low vacuum
  filtration onto precombusted GF/F filters. Volumes collected were
  adjusted according to depth, expected carbon concentration and filter
  color (generally 1-4 liters). Filters were removed from the manifold
  before they dried and were stored folded in half in plastic envelopes
  in a dessicator. The filters were returned to the USA on dry ice, and
  finally shipped to BBSR on dry ice for analysis.

  Samples were analyzed at Bermuda Biological Station for Research
  following the BATS protocols.  NB: Filters were acidified so the
  carbon analysis is for particulate organic carbon not total particulate
  carbon.