What are Dinoflagellates?ProtistsA type of AlgaeA major component of marine food chains90% of dinoflagellates are aquaticMicroscopic, largest are about 2mm

diameterThey reproduce asexually

Ceratium Dinoflagellates

Dinoflagellates in Symbiotic Relationships

• Some have a mutual relationship with cnidarians which make up coral reefs.

• Zooxanthellae dinoflagellates provide energy for coral in return for protection, shelter, nutrients, and CO2 needed for photosynthesis.

Dinoflagellates in Parasitic Relationships

• Some dinoflagellates that do not have chloroplasts must feed on other animals.

Zooxanthellae: Dinoflagellate algae in coral

Amoebophyra sp. : Parasitic Dinoflagellate

Pfiesteria

• Pfiesteria is a special parasitic dinoflagellate: it has the capability to become temporarily autotrophic by taking chloroplasts from other photosynthetic protists. Pfiesteria is responsible for many fish kills.

Structure and abilities• Most dinoflagellates are unicellular• Each species has a characteristic shape reinforced with plates

of cellulose. These plates are called thecae• Many have two flagella which creates a spinning movement• Some are even capable of bioluminescence for defense,

offence, camouflage, and communication

Dinoflagellate Structure

Life Cycle of Dinoflagellates1. Asexually reproduce: are

haploid2. Act as gametes, pair up, and

form diploid zygotes3. Make new theca (the

cellulose plate)4. Flagella are lost, thecal

plates break off and red pigments are produced (this is known as blooming)

5. Dinoflagellates then rest on the sea floor

6. Undergo dormancy and then division

Red tidesRed tides

Review Questions

1. What are the cellulose plates of dinoflagellates called?o thecae

2. Name three reasons for bioluminescence.o Three of: defense, offence, camoflauge, communication

3. What is special about a Pfiesteria?o It can temporarily take chloroplasts from other photosynthetic protists making it temporarily autotrophic.

4. Why does a red tide occur?o When the dinoflagellates bloom

5. Why are red tides dangerous?o Toxins

6. Name an example of a symbiotic relationship involving dinoflagellates.o Zooxanthellae and Coral

1. Video: http://www.youtube.com/watch?v=q6CefMUMtv42. For more information on Dinoflagellates, click here