Plankton

Phytoplankton

• Can’t move against currents (float or

weakly move)

• >40% of global primary productivity

Phytoplankton Classification

From two kingdoms Monera (bacteria)

Protista (algae)

3 divisions (Phyla)CyanobacteriaChrysophytaDinophyta

Cyanobacteria

•Photosynthetic bacteria •Prokaryotic (No

nucleus, few organelles)

•Reproduce by cell fission

•Nitrogen fixation: convert Nitrogen gas

(N2) to nitrates or ammonia

Chrysophyta• Most with hardened cell walls or

internal skeletons: silica or calcium carbonate (CaCO3)

•Some have flagella for motility

Coccolithophores – type of Chrysophyta

Calcium CaCO3 plates

•large numbers at surface

•Prefer still, nutrient-poor H2O

•Reflect sunlight: lower heat & UV light – counter global warming

Diatom – type of Chrysophyta

• Most abundant phytoplankton

• Major oceanic primary producer

• Cell walls (frustule) of silica (glass-like)

• Live alone or in chains

Dinophyta

Dinoflagellates

•Most photosynthetic, few heterotrophic

•Unicellular, 2 flagella: adjust vertically in

water column (light, nutrients)

•Rapid asexual cell division

Dinoflagellates

• Abundant in warm surface H2O (tropics)

•Some symbiotic (zooxanthellae)–Live in coral, clams, urchins, anemones

•Zooxan. give carbohydrates & receive nutrients & shelter

Dinoflagellates areBioluminescent

• Organisms produce light by a chemical reaction

Why Do Dinos. Produce Light?

Camouflage!

•When it senses a predator

(motion in H2O)

•Which attracts larger predators that

consumes the would-be Dino predator

Red Tides (Dinoflagellate Bloom)

• Mass development of dinoflagellates discolor water

•Often caused by excess nutrients

•Enter ocean from land (runoff)

•Fertilizer, sewage

Red Tide Impacts:

• Toxic to marine life: accumulates in clams, mussels, scallops, fish, mammals

•Death to some species, Human poisoning after consumption (30 min.)

•Symptoms:

•Paralytic: paralysis, asthma, heart attack (rare)

•Neurotoxic: tingling, paralysis,

memory loss

•Diarrhetic: cramps, vomiting, diarrhea

Special PlanktonicAdaptations

Unique shapes –increase surface areas•Gas filled-vesicles•Oils•Hard shells