1. Protists Dinoflagellates (Red tide, Zooxanthellae, Pfisteria) Diatoms
Cocolithophores
Radiolarians
Foraminiferans
Algal blooms

2. Dinoflagellates marine protists, some freshwater mostly unicellular
half are photosynthetic- primary producers of aquatic food chains
some live in mutualistic relationships with cnidarians, some are parasitic, some are carnivorous
two flagella- one transverse (lateral) and one longitudinal (posterior)
move in a whirling motion caused by transverse flagellum
have a submembrane made of cellulose--makes an “armor”

3. Red Tide
Certain dinoflagellates cause large algal blooms in warm coastal waters (such as along the east coast and in the Gulf of Mexico)
turn the water reddish brown because of xanthophylls in the chloroplasts
Shellfish eat the blooms and concentrate toxic compounds released by the dinoflagellate cells--toxic to other organisms

4. Zooxanthellae
golden-brown endosymbiont (lives inside) of marine organisms, especially anthozoans (coral)
typically dinoflagellate algae, but sometimes diatoms
aquired by ingestion
reproduce asexually by budding
autotrophs
gives coral 98% of its energy--in return is given protection, shelter, CO2 for photosynthesis- symbiosis

5. Pfisteria found in Pamlico and Neuse Rivers in NC
complicated life cycle- 24 physical forms, and can change forms quickly
most are non-toxic, but some have forms in their life cycles that are toxic
two toxins have been identified that can cause skin lesions and are neurotoxins

6. Diatoms phylum Bacillariophyta eukaryotic algae
unicellular, but some form colonies
cell wall made of hydrated silica in organic matrix called a frustule
marine and freshwater
yellow or brown in color
asexual or sexual reproduction- sperm only flagellated cells in this phylum

7. Cocolithophores
algae, protists, and phytoplankton in class haptophytes
have calcareous (calcium carbonate) shells- called cocoliths
index fossils- used to solve stratigraphic problems
also nanofossils- indicators of salinity and temp. changes on ocean surface

8. Radiolarians phylum Actinopoda- “ray feet” marine
shells made of silica (glass)
after radiolarians die, their shells settle on the sea floor and decompose into a siliceous ooze
often contain symbiotic algae like zooxanthellae

9. Foraminiferans
marine-live in sand or attached to rocks and algae- also some families abundant in plankton
have porous shells- “Foraminifera” means “to bear little holes”
shells are multichambered, made of organic material hardened with CaCO3
cytoplasm extends through pores- aids in swimming, shell formation, feeding
symbiotic algae often lives under shells
90% are fossils

10. Algal Blooms
rapid increase in the population of algae in an aquatic system
blooms of dinoflagellates cause red tides- produce neurotoxins
some algal blooms caused by an excess of nutrients- algae uses up all O2 and other organisms can’t survive (eutrophication, in freshwater lakes)

11. Sources
Campbell, Neil A. Biology: Third Edition. Benjamin/Cummings Publishing Company: New York, 1993.
Wikipedia.