Aquatic Macro

Invertebrates

and

Big River Journey

Aquatic Macro InvertebrateAquatic = water

Aquatic Macro InvertebratesAquatic = waterMacro = visible with your eyes

Aquatic Macro InvertebratesAquatic = waterMacro = visible with your eyes Invertebrate = animal without a spine

. . .like a mayfly

On the Big River Journey

Boat, you’ll see. . .

Aquatic Macro

Invertebrates!

Aquatic invertebrates These are tiny organisms, such as insects, that live in lakes, ponds, and rivers. We hardly noticed them, but they serve an important role. They feed on algae and other plants and are the base of the aquatic food chain.

-- daphnia (water flea) --amphipod

What’s an aquatic food web or food chain?

• It’s the story of what eats what. It includes everything that lives in or near the water:

Big things: people, turtles, raccoons, fox, eagles, ducks, birds, big fish, little fish, seaweed,frogs, clams and mussels.

Little things: macro invertebrates,insect eggs, snails, algae, aquatic worms, tadpoles, phytoplankton (tiny aquatic plants), zooplankton (tiny aquatic animals).

Food Web

Source: http://www.epa.gov/acidrain/education/site_students/foodweb.html

http://commons.wikimedia.org/wiki/File:Chesapeake_Waterbird_Food_Web.jpg#file

Did you know?Many aquatic invertebrates, like this damselfly, spend their nymph

stage in water. A nymph is the stage of development between egg and adult.

When the nymph development is complete, the mature nymph climbs from the water and flies off to begin its adult stage. It then breeds and returns to the water to lay eggs. The cycle begins again.

Damselfly nymph adult

Insect Metamorphosis

www.watershed.nau.edu

Mayflies may spend two years as nymphs living in water before developing into adults and flying in the air. After hatching as adults, they live from a few hours to three weeks. As adults, they do not eat--they have no mouth parts! The job of adult mayflies is to mate during their short life. Females return to the water to lay their eggs.

--mayfly nymph

A Mayfly hatch on Lake Superior

Mayflies are highly sensitive and can only live in clean water

The Mosquito

Mosquitos undergo four stages of development over a 15- 20 day period. 1) They begin life as an egg laid on the surface of ponds and quiet waters.2) In the larval stage (left), they hang and breathe from the water surface,

and feed on algae and microscopic animals.3) In the pupa stage, they also hang from the water surface and may swim

about. 4) When they emerge as adults, they rest on the water surface to dry their

wings then fly off to mate and return to the water to lay their eggs. If the female has had a blood meal, more eggs will develop. Yes, only female mosquitos bite.

Giant Water Bug

• Giant Water Bugs can grow to 3”

• They use their forelegs to grasp and hold a tadpoles or other insects as they thrust in their sucking mouthparts.

• They live in lakes and ponds.

Macro Invertebrates can tell us if the water is clean or dirty.

• Some can survive in both clean and polluted water

--leeches --snails

Some can survive in Dragonflies: the nymph stage medium clean water (left) lives in the water 3-4 years before

emerging as a flying adult dragonfly (right)!

Macro Invertebrates can tell us if the water is clean or dirty.

Macro Invertebrates can tell us if the water is clean or dirty.

• Some can survive ONLY in clean water

--mayflies --caddisflies

Macro Invertebrates can tell us if the water is clean or dirty.

• Every species of animal has a range of physical and chemical conditions in which it can survive.

• Some invertebrates are sensitive and will not survive

in polluted waters, others will tolerate a little to a lot of pollution.

• In the cleanest ponds, lakes, and rivers, you’ll find the greatest diversity of aquatic invertebrates.

• In polluted waters, only a few species can survive.

Kinds of Ponds--Clean!

+ Natural shoreline with a variety of plants

+ no man-made structures

+ room for lots of wildlife

+ Natural shoreline

+ grasses at shore- Rain runs off from parking lots (cars leak oil and

this washes into the water) - Urban area with limited wildlife habitat

+ Natural shoreline

+ grasses at shore- Rain runs off from parking lots (cars leak oil and

this washes into the water) - Urban area with limited wildlife habitat

Kinds of Ponds--Medium Clean

Kinds of Ponds--Polluted

- No plants next to shoreline

- chemical pollution

+ Some trees might attract wildlife

(Arizona)

Collecting Specimens• Take the “D” Net and a

bucket to the pond-->drag the net through the

weeds along the shore in the shallow water

-->Examine net for invertebrates, hand pick out inverts and place into bucket

. . .Repeat

--Stop and listen to the sounds of nature

Aquatic Invertebrates in the Winter• In the winter,

invertebrates are inactive.

• They’ve adapted to survive over-wintering, freezing and then thawing.

• Insect eggs wait in the mud for the water to warm in the spring.

• Algae still grows and fish swim about.

See you on the River Boat!

Photo credits:• Photos from Wikimedia Commons, a copyright free internet photo source or other sites as noted• BRJ photos and others by Kate Hintz, Science Museum of MN• Photos from vernalpool.org, used by permission• Lyndon Torstenson, NPS