zygote
352
duced by larger zooplankton sink rapidly and produce food for benthic
organisms, but coprophagy also occurs (particularly in Copepoda). Herbivorous
feeding also releases nutrients which are used in so-called regenerated primary production (~new production). Copepods often dominate zooplankton.
zooplankton samplers although the smaller zooplankton, the microzooplankton,
could be collected in sufficient quantities by taking water samples with the
usual types of samplers, most of the zooplankton has too Iowa density for this
approach. For the quantitative study of the different groups of larger zooplankton, a variety of nets and samplers exists, which filter larger volumes
through fine plankton gauze (Le., nylon netting with meshes from 30 Jlm to
several mm). Nets can be hauled vertically from bottom to surface or used
horizontally in the current or towed behind a boat, with double oblique
hauls. A current meter in the mouth opening provides an estimate of the volume of water filtered. Closing devices allow the sampling of separate strata
and are operated mechanically (by messengers; Juday net, Nansen net,
Clark-Bumpus sampler), electrically (Gulf III high-speed sampler, various
multinets, or nets with a rotating set of cod ends), or acoustically
(Rectangular Midwater Trawl). Detailed vertical profiles of zooplankton are
also made by large pumps (up to ca. 100 m depth) and by the LonghurstHardy Plankton Recorder (~Continuous Plankton Recorder).
zygote the fertilized ovum before cell division and differentiation.
352
duced by larger zooplankton sink rapidly and produce food for benthic
organisms, but coprophagy also occurs (particularly in Copepoda). Herbivorous
feeding also releases nutrients which are used in so-called regenerated primary production (~new production). Copepods often dominate zooplankton.
zooplankton samplers although the smaller zooplankton, the microzooplankton,
could be collected in sufficient quantities by taking water samples with the
usual types of samplers, most of the zooplankton has too Iowa density for this
approach. For the quantitative study of the different groups of larger zooplankton, a variety of nets and samplers exists, which filter larger volumes
through fine plankton gauze (Le., nylon netting with meshes from 30 Jlm to
several mm). Nets can be hauled vertically from bottom to surface or used
horizontally in the current or towed behind a boat, with double oblique
hauls. A current meter in the mouth opening provides an estimate of the volume of water filtered. Closing devices allow the sampling of separate strata
and are operated mechanically (by messengers; Juday net, Nansen net,
Clark-Bumpus sampler), electrically (Gulf III high-speed sampler, various
multinets, or nets with a rotating set of cod ends), or acoustically
(Rectangular Midwater Trawl). Detailed vertical profiles of zooplankton are
also made by large pumps (up to ca. 100 m depth) and by the LonghurstHardy Plankton Recorder (~Continuous Plankton Recorder).
zygote the fertilized ovum before cell division and differentiation.