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Ref. No. [UMCES] CBL 2015-008
ACT VS15-01
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monitored continuously and the salinity of the sample stream was measured on duplicate sub-
samples with a Guideline Portasal. Once during the stable phase of a given T-S test condition a
more detailed burst sampling was conducted, where 6-8 samples were collected over the course
of an hour to assess the fine-scale variability (temporal and spatial) of test tank conditions.
During the pH cycling phase of the test, 2 reference sampling timepoints were completed during
each endpoint (approximately an hour after acid/base addition) of the increase or decrease. Each
phase (increase or decrease) occurred over roughly 2 hour intervals.
Lastly, duplicate water samples were collected at the beginning and end of the stable test
condition period (day 1 and day 5) to characterize all of the CO
2
parameters. Water samples
were taken for pCO
2
, Dissolved Inorganic Carbon and Total Alkalinity measurements and
preserved and stored in accordance with standard oceanic protocols (Dickson et al., 2007). These
water samples were shipped to Oregon State University (Burke Hales, OSU) and Scripps
Institute of Oceanography (Andrew Dickson, SIO) for analysis. In addition, preserved water
samples were shipped to SIO (Andrew Dickson) and University of South Florida (Robert Byrne,
USF) for measurements of pH, thereby providing further indication of the uncertainty of ACT’s
reference sample measurements. However, because these samples were not handled identically
to the reference samples analyzed real-time and directly from the test tank, they will not be used
in any direct assessment against the test instruments without review from the TAC and consent
from the manufacturer. Nutrients were also measured on these samples in Atkinson's lab.
Moored Field Tests
Moored field tests were conducted at four ACT Partner Institution sites covering
freshwater, estuarine, and open-ocean conditions. The test sites include Moss Landing Marine
Laboratories (MLML), CA; Hawaii Institute of Marine Biology (HIMB), HI; Chesapeake
Biological Laboratory (CBL), MD; and Lake Michigan, MI. The field tests occurred in
sequence, starting with Moss Landing on August 22, 2013. The duration of the moored
deployment tests were 4 weeks, except at the Hawaii test site where instruments were deployed
for a period of 12 weeks. Instruments were removed from the water only after the test period
was complete.
Instrument Setup
– Prior to deployment, all instruments were set up at the field site by a trained
ACT staff member following established protocols that had been developed in collaboration with
the manufacturers at the training session that occurred in December, 2012 (at the beginning of
the ACT laboratory test). Manufacturers that did not conduct an in-person training session sent
written protocols and video demonstration of desired handling procedures. As appropriate, and
where requested by the manufacturer, submitted test instruments were initially calibrated by
ACT staff using a common batch of commercial, non-dyed, NIST traceable buffers at a pH of
7.02 and 10.06. (Each sensor was calibrated with buffer from its own bottle, but they were all
from the same LOT and shipment). All calibrations occurred in a constant temperature bath at
20.0
o
C (except at HI which was done at 25°C). Any deviation from this temperature was noted
and used to adjust the stated pH values of the buffers as defined on the bottles.
After calibration and prior to deployment (again where appropriate for each instrument)
instruments were exposed to additional certified reference solutions. At Moss Landing, CBL and
Hawaii, instruments were exposed to batches of Seawater CRMs produced by the CO2-QC
facility at Scripps Institution of Oceanography. (CRMs were batched into a single container