Environmental Engineering Reference
In-Depth Information
zones:
rstly by turbidity which can limit phy-
toplankton production and thus restrict the ration
supply for the zooplankton community, and
secondly by currents which, particularly in small
estuaries are dominated by high river
biomass of primary producers. This is the basis
of evaluating potential
shing zone (PFZ), which
is detected from the satellites. It is very important
to note in this context
that satellites do not
ow that
usually carries the zooplankton out to the sea.
The zooplankton biomass can increase the
fl
observe
sh stocks directly, but measurements,
such as sea-surface temperature (SST), sea-sur-
face height (SSH), ocean colour, ocean winds
and sea ice, characterize critical habitat
sh-
ery productivity because they chie
y consume
the primary producers (phytoplankton) and form
the major food source for members of higher
trophic levels in which several species of oste-
ichthyes and chondrichthyes exist. Zooplankton
are classi
fl
that
in
sh stocks.
Most of the spatial features that are important to
marine ecosystems, such as ocean fronts, eddies,
convergence zones, river plumes and coastal
regions, cannot be adequately resolved without
satellite data. Chlorophyll, present within the
phytoplankton, is the only biological component
of the marine ecosystem accessible to remote
sensing (via ocean colour) and as such provides a
key metric for evaluating the health and pro-
ductivity of marine ecosystems on a global scale.
Long-term ocean colour satellite monitoring
provides an important tool for better under-
standing of the marine processes, ecology,
fl
uences marine resources including
ed according to their habitat, depth
distribution, size and duration of planktonic life
(Tables
2.10
,
2.11
,
2.12
and
2.13
).
2.2.2 Osteichthyes
Bony shes are found at all depths and in all the
oceans, but
their distribution is determined
directly or
indirectly by the abundance and
sh
Table 2.10
Classication of zooplankton on the basis of habitat
Type
Description
Oceanic plankton
These are marine zooplankton that inhabit beyond the continental shelf
Neritic plankton
These zooplankton inhabit waters overlying continental shelves. These waters are often very
productive as they receive the runoff from the adjacent landmasses that triggers the
phytoplankton growth in these regions
Brackish water
plankton
These zooplankton inhabit estuarine regions, where there is a continuous mixing of fresh water
and sea water. The zooplankton species of this category have wide range of tolerance to
different dilution factors. Such zooplankton are very common in the shrimp culture farms and
form important diet of the prawns
Table 2.11
Classication of zooplankton on the basis of depth distribution
Type
Description
Neuston
The zooplankton of this category are restricted at the top few millimetres (usually 10 mm) of the
surface microlayer
Pleuston
These are widely distributed at the surface of the sea (with parts of the body sometime projecting
above the water)
Epipelagic
These are distributed between 0 and 300 m water column, e.g. siphonophores, arrow worms
Mesopelagic
The zooplankton of this category are restricted within the depth 300
1,000 m, e.g. euphausiids,
-
chaetognath
Bathypelagic
These are restricted within the depth 1,000 and 3,000 m, e.g. foraminifera, euphausiids
Abyssopelagic
The waters overlying the vast abyssal plains of the ocean are inhabited by a variety of zooplankton
species, which is often referred to as abyssopelagic zooplankton. These zooplankton are thus
restricted between 3,000 and 4,000 m
Source
Santhanam and Srinivasan (
1998
)
