Plankton

What is Plankton?

Animals and plants that either float passively in the water, or possess such limited powers of swimming that they are carried from place to place by the currents.

Where does the word “plankton” come from? The word plankton comes from the

Greek word planktos, which means ‘wandering’ or ‘drifting’.

Where are plankton found? Plankton dominates the well-lit

surface layers of the world's oceans.

Types of Plankton

Phytoplankton- microscopic plants and bacteria.

Zooplankton- microscopic animals

Phytoplankton

Carry out photosynthesis.

Produce 80% of the Earth’s oxygen and 75-80% of the organic matter.

Why must they live in the photic zone?

Can undergo rapid population growth or “algae blooms” when water temperatures rise in the presence of excess nutrients.

During a bloom most phytoplankton dies, sinks to bottom and decomposes.

This depletes the bottom waters of dissolved oxygen which is necessary for the survival of other organisms.

Plankton BloomPicture taken by astronauts from the International Space Station.

Location: the Capricorn Channel off the Queensland coast of Australia.

Trichodesmium -- photosynthetic cyanobacteria, also called "sea saw dust"

Phytoplankton

Impact of Ozone on Phytoplankton Produce more oxygen than all plant life on

earth and are vital in maintaining the earth’s atmosphere.

They are also the organisms most likely to be affected by global warming and climate change.

Scientists around the world are concerned that harmful rays from the sun could pass through the hole in the ozone layer and kill phytoplankton, which live mostly in the upper layers of the ocean.

Diatoms Single-celled yellow green algae. Have a cell wall. Cell wall contains silica, a glass-like

substance. Come in lots of shapes and sizes Intricate lines and etchings

Word “diatom” means cut in two because its cell wall is made of 2 parts one fitting over the other.

Kind of like a petri dish!!!

Diatoms

Probably the single most important food source in the ocean!!!!

YUMMMY!!!

Eaten by small plankton and by larger oysters and clams.

Dinoflagellates

Propel themselves using 2 flagella Can swim like simple animals Photosynthesize like plants

2 Species: Gonyaulax & Gymnodinium responsible for Red tides

What is a Red Tide?

Plankton-rich water. Responsible for fish mortality and

paralytic shellfish poisoning.

Zooplankton

Floating or weakly swimming animals that rely on water currents to move any great distance.

– Microzooplankton (< 200 microns) in size

– Mesozooplankton (200 microns- 2 mm) – Macrozooplankton (> 2 mm)

Classified according to sizeSmallest Largest

Nannoplankton (Ex. Protozoans)

Microplankton (Ex. Primarily eggs and larvae, usually of invertebrates).

Macroplankton (Ex. Copepods)

Megaplankton (Ex. Portuguese Man of War)

Camouflage

Zooplankton are the favorite food of a great many marine animals so camouflaging themselves is a very important survival strategy.

Developing effective camouflage when you live in clear, blue water is no easy matter.

The best solution and the one most often used by members of the zooplankton is to be as transparent as possible or, in the case of many surface floating jellyfishes, blue.

There are two major types of zooplankton:

1) Those that spend their entire lives as part of the plankton (called HOLOPLANKTON)

2)Those that only spend a larval or reproductive stage as part of the plankton (called MEROPLANKTON).

Holoplankton

Blue Sea Slug Adapted for life floating upside

down in the sea and is often found with the beautiful blue jellyfish Porpita.

Blue Sea Slugs feed almost exclusively on the tentacles of 'Bluebottles'.

Interestingly, the nematocysts (stinging cells) on these tentacles pass through the Blue Sea Slug intact. The slug can then use these stinging cells in its own defense.

Holoplankton

A snail with a thin fragile shell containing only a heart and gills. It swims upside down. Can eat prey as large as itself with its toothy tongue (radula).

Heteropod Atlanta peronii

Polychaete Worm or bristle worm.

Most are mesoplanktonic.

Portuguese Man of War

Also called bluebottle.

They are a colony of polyps.

They feed using their long tentacles on surface plankton.

Meroplankton

Meroplankton spend only the larval or early stages of their life as part of the plankton and spend their adult lives on the reef.

Meroplankton

Many meroplankton bear little resemblance to the adults that they will become.

Meroplankton

While living in the plankton, meroplankton either feed on other members of the plankton, or they live off the yolk they have retained from the egg they hatched from.

Meroplankton

Larvae spend varying amounts of time in the plankton, from minutes to over a year.

However, just how long these tiny animals can be considered truly planktonic is under some debate.

Meroplankton- Examples

sea urchins Starfish sea squirts most of the sea snails and slugs crabs Lobsters Octopus marine worms most reef fishes.

Lobster Larvae

Meroplankton

Lobster Larvae

Anemone Larva & Adult

Sea Cucumber Larva & Adult

Brittle Star Larvae & Adult

Cone Shell Larvae & Adult

Octopus Larvae & Adult

Starfish Larvae & Adult

Meroplankton

Meroplankton that sinks to the bottom of the ocean and lives there is called BENTHOS.

Nearly 16% of all animal species are benthic.

There are 3 types:

INFAUNA- animals that live in the bottom like clams and worms

EPIFAUNA- animals on the bottom surface like crabs, coral and starfish

EPIFLORA- plants that live on the bottom.

Epidermis ( epi- means on the surface)

Nekton

Not plankton Swim Ex. Invertebrates & vertebrates (Squid) (Whales)

How long are they larvae?

Larvae spend varying amounts of time in the plankton, from minutes to over a year.

However, just how long these tiny animals can be considered truly planktonic is under some debate.

Scientists in recent years have discovered that many of these tiny animals in the plankton quickly become very good swimmers capable of incredible speed and endurance.

Marine Protozoa

Protozoan = one celled organism. Usually microscopic Most live in water Some are plankton, others benthic Three groups: Sarcodinians, ciliates,

flagellates.

Sarcodina

Word “sarcodina” means creeping flesh.

Describes how they move. Contract and expand projections of

their bodies called pseudopodia or “false feet.”

2 groups: forams & radiolarians

Facts about Forams

Shell made of Calcium carbonate. Pseudopodia project out through

holes in shell. Feed on diatoms & other

protozoans. Secrete digestive juices onto their

food to dissolve it!!! Waste expelled through body

surface.

Globigerina

Planktonic Large amount of these shells have been deposited in sediment. Studied to reveal information about

climate in past geological eras.

Archaias angulatus

Turtle grass foram

Archaias compressus

Button foram

Radiolarians

Mostly planktonic Perforated outer skeleton of silica. Pseudopodia extend through holes

as long, sticky filaments. Skeleton does NOT dissolve at

great depths like the Forams.

Radiolarians

Studied by micro paleontologists

Radiolarian Art

             

Artist: Barbara West Canada

Artist: Eva Bjerke (Sweden)

Ciliates

Covered with hair like cilia Cilia used in eating, locomotion,

respiration. Most are solitary and free

swimming. Some are attached and colonial. Common among sand grains (eat

plant cells and bacteria!)

Ciliates

Tintinnids

Bell animals Planktonic ciliates Common in open ocean Ring of cilia surround mouth (locomotion &

catching food). Hard shell of protein.

Phylum Mastigophora Flagellates Propelled by a flagella Whip like

Choanoflagellates

Colonial, live attached to bottom. Collar filters particles from the water.

The most abundant members of the zooplankton, both in species and total numbers are the crustaceans.

Crustaceans include lobsters, crabs, prawns, pill bugs, krill, barnacles, water fleas, brine shrimp (sea monkeys) and copepods.