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MERC - HYDAC Test Plan
5
The conical bottom mesocosms (shown below) have been installed on the
Cape
Washington
to allow for precise and controlled sampling during each test trial. One mesocosm
will be used for initial samples and a second set of three replicates for post filter samples. Each
mesocosm will be overfilled at a constant flow rate (controlled by a diaphragm valve), then the
water sample lowered to the measured volume of 1.05 m
3
. Each mesocosm filling will take
place over 10 minutes. Immediately (< 5 minutes) after filling of each mesocosm, physical
parameters of the water will be measured (see below), then the precise sample volumes described
below will be collected for zooplankton, phytoplankton, TSS and particle size distribution by
gravity draining through a bottom valve and tubing. After each use, all mesocosms will be top-
down rinsed thoroughly using a freshwater hose a minimum of three times, then kept clean and
dry between uses.
MERC test and sampling system on the
Cape Washington
.
Basic Water Quality:
A hand-held multi-parameter instrument will be used to measure temperature, salinity,
and dissolved oxygen of the water in each mesocosm (described above) as it is collected. This is
considered ancillary data and is simply meant to help characterize the ambient conditions during
testing.
Total Suspended Solids (TSS):
Immediately after filling each mesocosm, a subsample of 2 liters of water will be
collected, an appropriate amount filtered, then analyzed for TSS. Sample analyses will be
conducted using standard US EPA methods by the certified CBL/UMCES Nutrient Analytical
Services Laboratory (www.cbl.umces.edu/nasl).
Particle Size Distributions
Immediately after filling each mesocosm, a subsample of water will be collected, fixed,
then shipped to a certified laboratory for analysis of particle size distributions. The size
distribution of particles (range 0 – 2 mm) will be analyzed by the laser light scattering method
(ASTM D4464).