Dataset: POC

See: SO-GasEx cruise report, Section 5.7.14 pg 55

Operation description:
Discrete analysis of particulate organic carbon (POC) on CTD casts
(hydrography) and ship's underway seawater line.

Sampling times and locations:
Sampled most CTD casts. One deep cast to 4600m, one mid-depth cast
to 1500m, other casts usually to 100m or 500m. See CTD cast logs and
bottle files for specific times, locations, and bottles for each cast.
See event log for times and locations when sampled underway seawater line.

Overall sampling strategy:
Normally collected one sample from six depths. Four samples collected
from the 5m bottle on CTD41 for error analysis and method comparison if
samples are run at two locations. Usually took four or more samples in
the mixed layer, one in the thermocline and occasionally one below the
thermocline.

Analytical method:
Water samples were drawn into a 1.17L polycarbonate bottle using a
latex rubber hose. Sample bottles and caps were rinsed once. Also
took very occasional underway samples - same filling procedure but
no latex hose and water was from outlet in stbd sink, main lab.
Samples were filtered at <20kPa vacuum onto combusted (450C for 12 hrs)
Whatman GFFs. Filters were dried for 12-24 hrs at 23C, <30% humidity,
and stored, folded, in cryovials or aluminum foil (Fred Meyer) envelopes.
Samples were transported to OSU, then acidified with 1ml 10% HCl and dried
again at 60C for 6hrs. Samples were then analyzed for CHN at the UCSB
Marine Science Institute Analytical Lab.

Instrument details:
Contact UCSB MSI Analytical Lab for details.