Zooplankton of the open Baltic: Extended Atlas - IOW

a
b
c
d
Figure 3.2.1: a, The WP-2 UNESCO Standard net being deployed
aboard the R/V A. v. Humboldt; b, Twenty cm and 60 cm Bongo nets ready
for deployment from the R/V Johan Hjort; c, The Multinet rigged for
horizontal towing from aboard the R/V A. v. Humboldt; d, Deployment of a
CalCOFI net from the R/V A. v. Humboldt. All photos stem from an
ICES/GLOBEC Sea-going workshop for intercalibration of plankton samplers
at Storfjorden, Norway, June 1993 (ICES, 2002).
Each of the recommended gear collects a certain fraction of plankton.
Occasionally collected organisms could be excluded by sieving in a
separatory column with graded sieves as proposed by UNESCO (1968) and
illustrated in Figure 3.2.2. The separated fractions theoretically contain the
organisms that are most ideally collected by each of the samplers. The sum of
the concentrations of the separate results should give the best estimate of the
“total plankton concentration”. Examples for such strategies are published by
Witek and Krajewska-Soltys (1989), Quinones et al. (2003), and Postel et al.
(2007).
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