Osmotically pumped chemical analyzers are being developed
at MBARI by Hans Jannasch, Carole Sakamoto and Kenneth Johnson. The completely
self contained analyzers are mounted on mooring cables or on instrument
cages and continuously measure dissolved nitrate concentrations for over
three month time periods (1/e response time <13 min, 1 reading taken
each each 5 to 15 minutes depending on available SRAM). OsmoAnalyzers measuring
dissolved nitrate have been deployed on moorings in Monterey Bay, at the
JGOFS Time Series sites off of Bermuda (BATS) and Hawaii (HOT), on several
DOE/OMP moorings off Cape Hatteras and on two of the TOGA/TAO moorings
on the equatorial Pacific.
We are currently adapting this technology to analyze for
S=, with further plans to adapt colorimetric determinations
for Mn and Fe, and PO4 and Si. A more complete description of
the analyzers can be found in Jannasch et al., 1994, Anal. Chem., 66, 3352-3361.
The bare OsmoAnalyzer in the laboratory. From left to right are the sample
pump (NaCl and membranes visible in the top and bottom compartments, respectively),
the reagent pumps (on orange tubes), the support plate (with the manifold,
source and detector on top), and the standard and blank injection pumps.
The analyzer is 20 x 15 x 8 cm.
Deploying nitrate OsmoAnalyzers on the first HOT mooring
Mark Pickerill and myself on the fantail of the R.V. Moana Wave (Univ.
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