The Plankton
Drifters of the Open Ocean

Plankton
• Range in size - 0.005 mm to 15 m
• Include all the major kingdoms of life
• Floaters
– Distribution determined by surface currents

Types of Plankton
• Size Categories
– Unltraplankton
– Nannoplankton
– Microplankton
• Phytoplankton
• Zooplankton

Phytoplankton
• Major Groups
– Diatoms
– Dinoflagelates
– Coccolithophores
• Protista
• Planktonic plant = Sargassum

Phytoplankton
• Diatoms
• Silica impregnated, porous cell wall
– Frustule - 2 halves
• Asexual and sexual reproduction
• Very rapid division = bloom

Phytoplankton
• Diatoms
• Ecology
– Thrive in cold, nutrient rich waters
– 2 growth forms = centric & pennate
• Centric = best floater
• Pennate = shallow sea floor or attached

Phytoplankton
• Dinoflagelates
– Outer covering of cellulose
– 2 flagella
• Reproduce asexually
– Very rapid division
• Ecology
– Lower light levels
– Mobile
– Autotrophic & heterotrophic
– bioluminescent

Phytoplankton
• Coccolithophores
– Gelatinous covering with overlapping calcite plates (coccoliths)
• Asexual reproduction
• Ecology
– Widely distributed but with a preference for warmer water

Oil Spills and the Ocean System
• The Prestige - oil tanker that completely sank today
• Northwestern Spain - 200 km offshore - 3600 m deep
• Is sinking the worse thing that could happen?
• A slick 70 miles long and 5 miles wide - did it spread out?
• How is petroleum bad for the environment?
• Is it a completely foreign substance in the ocean?
• What have the oil companies learned from the Exxon Valdez

Zooplankton
• Very diverse group
• Grazing and carnivorous heterotrophs
• Reproduction = high, life span = short
• Limited mobility
• Patchy distribution
• Concentrations along density boundaries
• Vertical migration

Zooplankton
• Crustaceans
• Copepods
– Most abundant primary consumers
– Small Grazers
– Rapid reproduction
• Euphausiids - krill
– Larger
– Carnivorous
– Food for baleen cetaceans
– Females lay up to 10,000 eggs

Zooplankton
• Forams & Radiolarians
• Protista - very diverse groups
• Forams = calcite, Rads = silica
• heterotrophs

Zooplankton
• Ctenophores and Cnidarians
• Ctenophores = “comb jellies” - bioluminescent
• Cnidarians = jelly fish (solitary or colonial) - medusa
• nematocysts

Zooplankton
• Pteropods
– Planktonic gastropods
• Meroplankton versus holoplankton
– Larval stage of benthic or nektonic forms

Ultra- and Nannoplankton
• Bacteria
– Autotrophs and heterotrophs
– Extremophiles
• Viruses
– Parasitic cells

Sampling the Plankton
• Plankton Tows

Problems from plankton - marine toxins
• HAB’s - harmful algal blooms - “red tides”
• Toxins produced by dinoflagellates
• Shellfish
• neurotoxins