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193

phytoplankton

OLogy Series
biology
card
193

phytoplankton

OLogy Series
biology

Phytoplankton are microscopic organisms that live in the ocean. They use sunlight to grow and make food. They also produce the oxygen we breathe. Just as plants form the basis for the ecosystem on land, phytoplankton form the basis for the ocean ecosystem. Every ocean animal, from the tiniest fish to the largest whale, depends on phytoplankton for survival. Even if an animal doesn't eat phytoplankton, it eats another animal that does, or animal that eats that animal, and so on.

Phytoplankton are like plants because they carry out photosynthesis. In other words, they:

have leaves and roots

need nutrients from soil to grow

use energy from the Sun to make their own food

Are you right?

Correct!

Phytoplankton, like plants, carry out photosynthesis. They use the energy from the Sun to make their own food. Phytoplankton have this ability because they contain pigments like chlorophyll, the same chemical found in plants.

Phytoplankton are most plentiful:

near the ocean's surface

in the middle layer of the ocean

near the ocean's bottom

Are you right?

Correct!

Since phytoplankton need sunlight to survive, they are most plentiful near the ocean's surface.

Phytoplankton are really just tiny plants.

Fact
or
Fiction
?

Fiction

Phytoplankton are algae, which are not plants because they lack roots or leaves. Even though, like plants, they make their own food, algae belong to a group called "protists."

Phytoplankton are distributed evenly around the world's oceans.

Fact
or
Fiction
?

Fiction

Phytoplankton are found in patches, depending on the water's temperature and supply of nutrients. These patches are always changing with ocean currents.

Description: tiny, plant-like algae
Size: microscopic
Habitat: oceans around the world
Characteristics: a variety of sizes, shapes, and colors
Examples: diatoms, dinoflagellates
Cool fact: in Greek, "phytos" means plant, and "planktos" means wanderer

Image credits: Sean Murtha.