Environmental Engineering Reference
In-Depth Information
Frustulia is a benthic form living on sed-
iments. A widespread genus, found in a
range of pH waters. Cells (50-160 μm
long, 10-27 μm wide) rhomboid to lance-
olate, contain two plate-like chloroplasts.
Found singly or occasionally in mucilagi-
nous tubes and in slightly acidic waters.
Bacillariophyta. Plate XXVII.
join together in small groups of up to 8
cells. 1-8 chloroplasts per cell, each with
a pyrenoid. Planktonic in lakes and ponds
(Fig. 4.72).
(b) Cells with 3-8 spines arising from
each pole. . ................. Chodatella
Cells of Chodatella are oblong to ovate
(6-18 μm wide, 10-21 μm long) and
contain 1-4 chloroplasts, each with a
pyrenoid. The spines are fine, 10-24 μm
long. Chlorophyta. Planktonic in lakes and
ponds. Plate XXVIII.
204 (126) (a) Cells ovoid to spherical . ........ 205
(b) Cells other shape (note cells with a
median groove, although roughly oval in
outline, are included here).. ......... 210
205 (204) (a) Cells bearing spines.. ........... 206
NB . Chodatella is now usually included
in with Lagerheimia.
(b) Cells without spines... . . . ....... 209
209 (205) (a) Cells small and spherical (
10 μmin
diameter).................... Chlorella
<
206 (205) (a) Cells spherical or only very slightly
oval.............................. 207
Chlorella cells (2-10 μm diameter) are
spherical to sub-spherical with a single
parietal chloroplast which nearly fills the
cell. A single pyrenoid is present. Com-
mon in nutrient-rich waters but easily
overlooked because of their small size.
Its small size also means that it can pass
through traditional water treatment sand
ilters,givingrisetocolourproblemsinthe
treated water. Chlorophyta. Plate XXVIII.
Fig. 4.74
(b) Cells oval to elliptical .......... 208
207 (206) (a) Cells solitary, spherical, 5-21 μm
in diameter. Numerous fairly long (rel-
ative to the cell diameter) spines
........................... Golenkinia
Golenkinia cells are solitary but may form
false colonies when they fail to separate
after division. Cells have several spines
(12+), 24-45 μm long, and contain a sin-
gle cup-shaped chloroplast with pyrenoid.
Planktonic. Chlorophyta. Fig. 4.72
(b) Cells ovoid and
>
10 μminsize
Oocystis
(b) Cells sometimes solitary though usu-
ally in colonies of 8-16 cells. Cells ovoid
to spherical, 3-7 μm diameter. 1-5 spines
per cell each 20-35 μm long (see Section
96,Fig.4.72)............ Micractinium
Oocystis has ovoid to egg-shaped cells
that are either solitary or in small groups
of 2, 4, 8, or 16 cells enclosed by the
mother cell wall (sometimes quite faint
and difficult to see). Cells may have
thickened poles (polar nodules). Cells
(7-50 μm long, 6-12 μm wide) con-
tain one to many discoid or plate-like
chloroplasts. Pyrenoids may or may not
208 (206) (a) Cells with two to many spines arising
at each pole. .............. Lagerheimia
Cells of Lagerheimia are ovate (6-18 μm
in diameter, up to 23 μm long) and can
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