standardization of environmental data and information - International ...

of pigments by high-performance liquid chromatography (HPLC)
and epifluorescence cell counts, a good idea could be obtained
of what was present and how much. Phytoplankton work would
be done only in the upper 200 m, while microscope counts and
C-14 productivity studies would probably be done at least at two
depths in the surface layer and in the chlorophyll maximum.
?? Microzooplankton, defined as plankton smaller than 200 µm:
An agreed mesh size of 200 µm should be chosen. Zooplankton
workers had used a range of sizes from 200-500 µm; however,
particularly in open ocean regions where the zooplankton
tended to be quite small, a coarse mesh would miss a great
deal of it, hence the proposal to standardize on 200 µm. The
standard method was to use an inverted microscope for
examining several water samples. Biomass was typically looked
at by estimating volume. Standard dilution experiments would
be useful to examine the role of the microzooplankton in grazing
the phytoplankton.
?? Mesozooplankton: Agreement should be reached on a standard
set of sampling depths to look at the zooplankton, consisting of
surface-200 m, 200-500 m, 500 m-oxygen minimum and two
tows in the bathypelagic zone. While a simple opening/closing
net could be employed, to carry out a set of stratified tows it
would be easiest and most efficient to use a device such as a
Multiple Opening and Closing Net and Environmental Sensing
System (MOCNESS) or a Biological Net and Environmental
Sampling System (BIONESS), which were standard in a number
of areas. Biomass could be looked at either through
displacement volume or dry weight, while abundance was
typically assessed through microscope counts.
?? Micronekton: The same depths should be sampled as for
plankton. Again, there was a wide range of samplers, but one
possibility was something like the MOCNESS-10, an
opening/closing net system that had a 10-m² mouth opening,
enabling it to sample the depths quickly and efficiently. The
standard treatment of micronekton was to sort the catch into
species groups and then carry out counts and weights by
species.
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