What are plankton?

The word plankton comes from the Greek ‘planktos’, which means wandering or drifting. It describes the millions of free-floating organisms living in the ocean and other aquatic ecosystems.

Many kinds of organisms make up plankton; some spend their entire life drifting in the upper ocean, others are members of the plankton community for a time before they develop into stationary or free-swimming adults.

There are three main types of plankton:

• Plant plankton, also known as phytoplankton • Zooplankton• Bacteria

KINGDOM MONERA

KINGDOM MONERA

• Cyanobacteria – a moneran phytoplankton– Photosynthetic and can fix atmospheric nitrogen– Reproduce by fission– Can aggregate to form colonies– bacteria - single-cell, no organelles

• cyanobacteria - blue-green ‘algae’– photosynthesis but no chloroplasts– chlorophyll a + phycocyanin– produced first O2 in atmosphere

• photobacteria - bioluminescent– in plankton & animal tissues

• thermobacteria - chemosynthesis– convert hydrogen sulfide H2S– in hydrothermal vents & hot springs– base of aphotic food chains

Bacteria – some are photosynthetic, but the majority feed on dead organisms.

• For centuries, sailors in the Indian Ocean have told stories of seas glowing with a dim, white light at night. Satellite images have now confirmed the appearance of what seem to be bioluminescent bacteria, right where a ship's crew reported seeing the "milky seas" 11 years ago. Scientists say this rare phenomenon could be a way for the bacteria to attract the attention of fish so they can enter their guts and live there.

Bioluminescent Bacteria

Cancer Killer Found In The OceanMarine Biotechnologists Treat Cancer With Mud-loving Ocean Bacteria

• Biomedicine scientists identified and sequenced the genes of a bacteria called Salinispora tropica. It produces anti-cancer compounds and can be found in ocean sediments off the Bahamas. A product called salinosporamide A has shown promise treating a bone marrow cancer called multiple myeloma, as well as solid tumors.

Protistan phytoplankton

• Phylum Chrysophyta• Single celled• Silica or calcium

carbonate internal skeleton• 2 marine groups

– Golden brown algae– Diatoms

• Most abundant• Cell wall(frustule)• Asexual reproduction• Can reproduce one million

daughter cells in 3 weeks

• Phylum Dinopyhta– Dinoflagellates

– Have flagella

– Responsible for red tide that interferes with nerve impulses

– bioluminescent

Plankton naturally sink and are brought up through the water column by mixing and upwellings

Phyto plankton(plant) (free floating)

Plant plankton, also known as phytoplankton – single-celled photosynthetic organisms which manufacture food using energy from sunlight.

Zoo plankton(animal) (free floating)

Zooplankton – single- and many-celled animals that feed on live plankton.

Phylum Sarcomastigophora• Radiolarians

– Entirely marine

– Internal skeleton of silica

– Have psuedopods

• Foraminiferans– Make up half of all

protozoans

– Mostly marine

– Have calcium carbonate shells(tests)

– Mostly benthic or live attached to another organism

White Cliffs of Dover – Foram tests or Globigerina

Phylum ciliophora

• Most abundant ciliate

• Have cilia

• Have tentacles that feed

• Mostly parasitic