227
1. Cyanophyta
2. Euglenophyta
3. Chlorophyta
4. Chrysophyta (which includes the diatoms)
5. Pyrrophyta
15.2.2 Zooplankton
The zooplankton, which are the primary consumers in the ecosystem, include many varieties. While some spend only a part of their lives
drifting at the surface, others are found to
extend to the deeper waters than the phytoplankton do. Many of them make daily sojourns
between layers.
The zooplankton could broadly be classifi ed
into the following groups:
1. Protozoa
2. Rotifera
3. Cladocera
4. Copepoda
5. Ostracoda
15.2.3 Methodology for Plankton
Study
The analysis of plankton is done after collecting
plankton samples generally in 50-ml polythene
tubes from both surface and bottom waters of the
waterbody. Samples from the surface water could
be collected by fi ltering 100 l of the water from the
waterbody covering the study area using 1-l capacity tumbler and operating from a canoe. Bottom
water plankton samples could be collected with
the help of a 5-l capacity Kemmerer water sampler. A plankton collecting net, made of nylobolt
bolting silk with mesh size of various diameters
(according to the group to be studied), but generally of 55 μm, is used to fi lter the water sample for
collecting plankton. At the time of collection,
extreme care be taken to disturb the water as little
as possible. The collected plankton samples be
preserved in 2–5 % (v/v) aqueous formalin solution on the spot and transferred to the laboratory
where the samples are to be centrifuged and the
plankton volume be recorded in ml. Each plankton
sample may then be diluted to 100 ml with DW
and mixed thoroughly. A sub-sample of 1 ml may
then be drawn from it with the help of a widemouth pipette and poured into a Sedgewick-Rafter
Plankton Counting Cell. While pouring, due care
be taken to ensure equal distribution of planktonic
organisms in the entire counting cell. Quantitative
estimation of the plankton (unit/l) be done
with the help of a stereoscopic microscope (Kar
1990 ). Limnoplankton are identifi ed after various
authoritative works, notably Ward and Whipple
( 1918 ), Smith ( 1950 ), Pennak ( 1953 ), Needham
and Needham ( 1962 ), Michael and Sharma ( 1988 ),
Battish ( 1992 ), Fritsch ( 1965 ) and so on.
15.2.4 Wetland Plankton Exemplifi ed
in Asian Wetlands
15.2.4.1 An Account of Limnoplankton
of Sone Beel
Forty-seven different forms of phytoplankton
belonging to fi ve groups, as indicated above, have
been recorded, till date, in Sone Beel. Of these, the
Chrysophyta included the maximum number and
Pyrrophyta, the least. The phytoplankton density
in the Beel varied from 48 to 5,308 (average 1,027)
units/l. The minimum population is generally
recorded during the rainy season and maximum
during the dry season. The cyanophytes and the
euglenophytes generally exhibit prolifi c growth
during the spring and summer with occasional
abundance during monsoon. The chlorophytes
usually show higher occurrence intensity during
summer and early monsoon with infrequent richness during winter and spring. The chrysophytes
are generally recorded throughout the year.
The pyrrophytes were found to register their
presence mainly during the autumn.
Nineteen different forms of zooplankton,
belonging to fi ve groups, as indicated above,
have been recorded, till date, in Sone Beel. The
zooplankton density varied from 6 to 380
(average 49) units/l. Low density is generally
recorded during February–March and high
density during November–December. In Sone
Beel, a considerable portion of zooplankton
population is considered to succumb to the
15.2 Wetland Plankton Communities
1. Cyanophyta
2. Euglenophyta
3. Chlorophyta
4. Chrysophyta (which includes the diatoms)
5. Pyrrophyta
15.2.2 Zooplankton
The zooplankton, which are the primary consumers in the ecosystem, include many varieties. While some spend only a part of their lives
drifting at the surface, others are found to
extend to the deeper waters than the phytoplankton do. Many of them make daily sojourns
between layers.
The zooplankton could broadly be classifi ed
into the following groups:
1. Protozoa
2. Rotifera
3. Cladocera
4. Copepoda
5. Ostracoda
15.2.3 Methodology for Plankton
Study
The analysis of plankton is done after collecting
plankton samples generally in 50-ml polythene
tubes from both surface and bottom waters of the
waterbody. Samples from the surface water could
be collected by fi ltering 100 l of the water from the
waterbody covering the study area using 1-l capacity tumbler and operating from a canoe. Bottom
water plankton samples could be collected with
the help of a 5-l capacity Kemmerer water sampler. A plankton collecting net, made of nylobolt
bolting silk with mesh size of various diameters
(according to the group to be studied), but generally of 55 μm, is used to fi lter the water sample for
collecting plankton. At the time of collection,
extreme care be taken to disturb the water as little
as possible. The collected plankton samples be
preserved in 2–5 % (v/v) aqueous formalin solution on the spot and transferred to the laboratory
where the samples are to be centrifuged and the
plankton volume be recorded in ml. Each plankton
sample may then be diluted to 100 ml with DW
and mixed thoroughly. A sub-sample of 1 ml may
then be drawn from it with the help of a widemouth pipette and poured into a Sedgewick-Rafter
Plankton Counting Cell. While pouring, due care
be taken to ensure equal distribution of planktonic
organisms in the entire counting cell. Quantitative
estimation of the plankton (unit/l) be done
with the help of a stereoscopic microscope (Kar
1990 ). Limnoplankton are identifi ed after various
authoritative works, notably Ward and Whipple
( 1918 ), Smith ( 1950 ), Pennak ( 1953 ), Needham
and Needham ( 1962 ), Michael and Sharma ( 1988 ),
Battish ( 1992 ), Fritsch ( 1965 ) and so on.
15.2.4 Wetland Plankton Exemplifi ed
in Asian Wetlands
15.2.4.1 An Account of Limnoplankton
of Sone Beel
Forty-seven different forms of phytoplankton
belonging to fi ve groups, as indicated above, have
been recorded, till date, in Sone Beel. Of these, the
Chrysophyta included the maximum number and
Pyrrophyta, the least. The phytoplankton density
in the Beel varied from 48 to 5,308 (average 1,027)
units/l. The minimum population is generally
recorded during the rainy season and maximum
during the dry season. The cyanophytes and the
euglenophytes generally exhibit prolifi c growth
during the spring and summer with occasional
abundance during monsoon. The chlorophytes
usually show higher occurrence intensity during
summer and early monsoon with infrequent richness during winter and spring. The chrysophytes
are generally recorded throughout the year.
The pyrrophytes were found to register their
presence mainly during the autumn.
Nineteen different forms of zooplankton,
belonging to fi ve groups, as indicated above,
have been recorded, till date, in Sone Beel. The
zooplankton density varied from 6 to 380
(average 49) units/l. Low density is generally
recorded during February–March and high
density during November–December. In Sone
Beel, a considerable portion of zooplankton
population is considered to succumb to the
15.2 Wetland Plankton Communities