Zooplankton.Pdf

Zooplankton Zooplankton Rotifers (zoe-uh-plank’-ton) Rotifers are small are consumers that animals. They are feed on phytoplank- often mistaken for ton. Most are so small single-celled ani- that you need a micro- Arthropod- mals. They are so Isopod scope to see them. Yet, named because they Scud they are important have tufts of hair (Amphipoda) parts of aquatic eco- that rotate and systems. Young fish move food toward Isopods are likely the largest of fry, or fingerlings, the mouth. Rotifers the animals called zooplankton. 1 need zooplankton to graze on phytoplank- Some can reach lengths of /2-inch. grow and develop. If ton. Some live free- They are very common in streams, there isn’t enough phy- floating. Others rivers, and lakes with lots of vegeta- toplankton, there attach themselves to tion. Two common kinds are the won’t be enough zoop- a plant and suck scud, or side-swimmer, and the sow lankton to feed the out the juices. Rotifer- bug. These critters are often large hungry growing fish. (Monostyla lunaris) enough for adult fish to eat! The amount of zoop- Arthropods Knowing more about zooplankton lankton in the water is Arthropods are the won’t help you catch more vital to gamefish popu- Rotifer- largest zooplankton animals. They fish. Still, knowing about lations. Zooplankton (Philodina have a shell, many legs, and large an- these critters can help you roseola) come from three tennas. The group of arthropods in- figure out why some wa- groups of cludes small crustaceans such as ters are more productive animals: protozoa, shrimp, fleas, copepods, side swim- than others. This infor- rotifers, and mers, or scuds, and isopods. mation can also help you arthropods. There are two main learn more about food webs. kinds of shrimp: fairy Protozoa and clam. Shrimp are Protozoa are single-celled animals. often less than one They move tails or hairs to capture inch in length. phytoplankton and move about. Water fleas are There are more protozoa in a water- abundant. They way than any other kind of animal. are active. They There are more than 30,000 different move by using very kinds of protozoa. large antennas like paddles. The most common water flea is daph- nia. Daphnia are less than .05 Protozoa- inches long! Paramecium Copepods are also abun- Arthropod- Arthropod- Paramecia are the most Water flea Copepod dant in freshwater (Daphnia (Cyclops common kind of protozoa. A para- habitats. They measure pulex) bicuspidatus) mecium is a shoe-shaped cell with less than 0.1 inches in illustration-Ted Walke hairs all around. These hairs move it length. They have very large antennas around in the water. Hairs also fan that are used to paddle the copepod food toward its “mouth.” around.

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