Protists of the Ocean
"Eukaryotes that are neither
Animals, Fungi, nor Plants"
Ameoba with ingested Diatoms
Paramecium
Lunch!
Plant like Protists
Autotrophic oxygen producers
• Euglena
• Algae
– Single celled
• Phytoplankton
– Cyanobacteria
– Diatoms
– Dinoflagellates
– Multi-celled
• Sea weeds
Euglena
• Has flagella
• Mostly lives in fresh
water
• Has light sensitive red
eyespot
• Autotrophic and
heterotrophic
Phytoplankton: Ocean Food!
• Derived from the Greek words phyto (plant) and plankton
(made to wander or drift), phytoplankton are microscopic
organisms that live in watery environments, both salty
and fresh.
• Some phytoplankton are bacteria, some are protists, and
most are single-celled plants. Among the common kinds
are cyanobacteria, silica-encased diatoms,
dinoflagellates, green algae, and chalk-coated
coccolithophores.
Algae: single celled
• Prokaryotic
– Cyanobacteria
• Single-celled to filamentous blue-green alga or
cyanobacterium
• Photosynthetic
• Produce much of the oxygen in the world
Life in a Glass House
• Diatoms
– Most abundant of single celled protists
– Account for 20% of photosynthesis
– Silica shells make them great fossils to study
Dinoflagellates
• The term "dinoflagellate" means
"whirling flagella"
• Each has two flagella
• Most are photosynthetic
• Some are parasitic
• Can cause problems with “blooms”
• Red tide
– produce a neurotoxin which affects
muscle function in susceptible organisms.
– Humans may be affected by eating fish
or shellfish containing the toxins.
– paralytic shellfish poisoning, or PSP (from
eating affected shellfish, such as clams,
mussels, and oysters)
– serious but are not usually fatal.
Seaweed
• Seaweeds are algae that live in the sea or in
brackish water. Scientists often call them
"benthic marine algae", which just means
"attached algae that live in the sea".
• There are about 10,000 species of seaweeds
• three basic colors: red, green, and brown
– Red and Brown are in salt water
– Green often in fresh water
Conjugation – Sexual Reproduction
Filamentous Green Alga
Colonial Algae
Multicellular Green Algae
Kelp Forests
kelp forest web
cam
Detrimental Aspects of Algae
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Blooms of freshwater algae
Red tides and marine blooms
Toxins accumulated in food chains
Damage to cave paintings, frescoes, and other works of
art
• Fouling of ships and other submerged surfaces
• Fouling of the shells of commercially important bivalves
Red tide bloom
• Prorocentrum micans
bloom
• Associated with
Hurricane Floyd,
which ended a dry
summer
• surface of water slick
with this dinoflagellate
Algal Bloom: Before and After
Red tide
Toxic Phytoplankton & Human poisoning
• Paralytic shellfish poisoning - saxitoxin
• Neurotxic shellfish poisoning - brevetoxin
• Ciguatera fish poisoning - ciguatoxin and
maitotoxin
• Diarrhetic shellfish poisoning - okadaic acid
• Amnesic shellfish poisoning - domoic acid
• Cyanobacterial neurotoxins - anatoxins
• Cyanobacterial hepatotoxins - microcystin,
nodularin
• Dermatitis - lyngbyatoxin, aplysiatoxin
Benefits of Algae
• used commercially for toothpastes, soaps, ice cream, tinned
meats, fabric printing etc,
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Food for humans
Food for invertebrates and fishes in mariculture
Animal feed
Soil fertilizers and conditioners in agriculture
Treatment of waste water
Diatomaceous earth (= diatoms)
Chalk deposits
Drugs
The total wholesale value of dried brown algae worldwide
collected in the wild or cultivated is less than $100 million
dollars.
Brown Tide
• Causes:
– Species: golden-brown algae
• Aureococcus anophagefferens, A. lanunensis
– Changes in groundwater, nutrients
• Impacts
– Zooplankton lose their appetites and die
– Reduced sunlight kills plants
– Death of bivalves (mussels, scallops etc)
• What can we do?:
– Less fertilizers!
Amnesic Shellfish Poisoning
• Causes
– Diatoms (Pseudo-nitzschia multiseries,
Paustralis)
• Impacts
– Toxin- domoic acid causes permanent loss of
short term memory and may be fatal
– Shell fish, crabs, and fish may be affected
– Sea lion, pelicans, and cormorants also
• What to do?
Diarrhetic Shellfish Poisoning
• Causes
– Phytoplankton like Dinophysis acuminata, D. fortii,
and Prorocentrum lima
• Impacts
– Toxins: lots of them
– Cause nausea, vomiting, abdominal pain and
diarrhea
– Affect mussels, oysters, scallops and the humans and
mammals who eat them
• What to do?
Neurotoxic Shellfish Poisoning
• Causes
– Dinoflagellates: Karenia brevis
• Impacts
– Toxins produced brevetoxin which affects manatees,
dolphins, oysters, fish, clams, and birds and humans
by consumption or breathing in the sea foam
containing the toxin
– Causes diarrhea, vomiting, neurologic symptoms, and
asthma-like symptoms. NO known antidote but most
recover in a few days
• What to do?
Paralytic Shellfish Poisoning
• Causes
– Algae Alexandrium
• Impacts
– Toxin affects mussels, clams, crabs, oysters, scallops,
herring, sardines, marine mammals, and birds, and
humans
– Symptoms include numbness, paralysis and
respiratory failure. No known antidote and death may
occur from respiratory arrest within 24 hours
• What to do?
Harmful Cyanobacterial Blooms
• Causes
– Excessive growths of cyanobacteria
• Impacts
– Toxins affect nerves, liver tissues in mammals, birds,
fishes and invertbrates
– Humans can be affected by inhaling toxins causing
nausea, diarrhea, stomach pain, difficulty breathing,
allergic reactions, skin irritation, liver damage, and
neurologic symptoms
– Increased turbidity so decreased light
• What to do?
Pfiesteria piscicida
• Causes
– dinoflagellate
• Impacts
– Flu like symptoms, skin rashes, memory loss
in commercial fishermen and women.
• What to do?