Download Chrysophytes and dinoflagellates

Chrysophyta--Golden brown algae
Cells small to medium (>10 microns)
Nucleus (1),
chloroplasts (2)brown to golden brown
(chlorophyll a plus carotenoids),
food stored mainly as oils and
carbohydrates
Unicellular or colonial, some species
with flagellae (usually 2)
Cell wall—often absent, sometimes
present as a lorica (cellulose)
(1a) simple unicellular naked flagellate—
Ochromonas and Chromulina
(1b) colonial forms, sometimes with cell walls(2)
(2a) flagellate colonial forms, a gelatinous
matrix may be present but lorica absent-Uroglena
(2b) large branched colonies, flagellate cells
within a lorica--Dinobryon
Ochromonas
Chromulina
Uroglena
50 microns
Dinobryon
Ecology of Chrysophytes
Common in the plankton of lakes especially during the colder parts of the year
May occasionally form blooms that colour the water brown and give taste and
odour problems—Eg Ochromonas
Some species also found in cold steams and springs.
Acid lakes and bogs, support a diverse Chrysophyte community, most important
primary producers in such systems.
Pyrrophyta--Dinoflagellates
•Cells fairly large (>25 microns)
•Nucleate (1),
•Cellulose wall often present
•Cells with grooves (sulci) within which flagellae lie
•Chloroplasts, 2 or more small disc shaped, brown
to golden brown (chlorophyll a, c, plus
carotenoids),
•Food stored as starch and oils
•Cells often emitting bioluminescence
•Cells very motile (8 mm/sec)
(1a) cells without an armoured wall, but with a firm
periplast with grooves for flagellae—Gymnodinium
(1b) cells armoured, with a sculptured cellulose wall
often consisting of several plates, perforated with pores,
and with deep transverse and longitudinal grooves—(2)
(2a) cells large (>100 microns) with lobe like extensions
“horns”--Ceratium
(2b) cells more or less spherical—Peridinium, Gonyaulax
About 30-50 microns
Ceratium—a dinoflagellate
> 100 microns long
Peridinium
40-60 microns
Gonyaulax—causes red tides, shellfish poisoning in estuaries
Cells about 25-30 microns
Ecology of dinoflagellates
Can be very important primary producers in both lakes and oceans
Many dinoflagellates occur as symbionts inside animals eg corals or sponges
Can cause toxic blooms, eg red tides, usually in estuaries—shellfish poisoning
Very motile can usually maintain their position in the water column if they remain
near the thermocline where turbulence is not too great
Can produce bioluminescence in response to disturbance of the water column or
predators.
Many species are heterotrophic and mainly live by ingesting bacteria (phagocytosis),
many such species have little chlorophyll.
Submerged macrophytes
Elodea canadensis
Valisneria
americana
Ceratophyllum
demersum
Potamogeton richardsonii
Floating leaved macrophytes
Nuphar luteum
Emergent macrophytes
Typha--cattails