MUD CREATURE STUDY Overview: The mudflats support a tremendous amount of life. In this activity, students will search for and study the creatures that live in bay mud. Content Standards Correlations: Science p. 307 Grades: K-6 TIME FRAME fOR TEACHING THIS ACTIVITY Key Concepts: Mud creatures live in high abundance in the Recommended Time: 30 minutes mudflats, providing food for Mud Creature Banner (7 minutes) migratory ducks and shorebirds • use the Mud Creature Banner to introduce students to mudflat and the endangered California habitat clapper rail. When the tide is out, Mudflat Food Pyramid (3 minutes) the mudflats are revealed and birds land on the mudflats to feed. • discuss the mudflat food pyramid, using poster Mud Creature Study (20 minutes) Objectives: • sieve mud in sieve set, using slough water Students will be able to: • distribute small samples of mud to petri dishes • name and describe two to three • look for mud creatures using hand lenses mud creatures • describe the mudflat food • use the microscopes for a closer view of mud creatures pyramid • if data sheets and pencils are provided, students can draw what • explain the importance of the they find mudflat habitat for migratory birds and endangered species Materials: How THIS ACTIVITY RELATES TO THE REFUGE'S RESOURCES Provided by the Refuge: What are the Refuge's resources? • 1 set mud creature ID cards • significant wildlife habitat • 1 mud creature flannel banner • endangered species • 1 mudflat food pyramid poster • 1 mud creature ID book • rhigratory birds • 1 four-layered sieve set What makes it necessary to manage the resources? • 1 dish of mud and trowel • Pollution, such as oil, paint, and household cleaners, when • 1 bucket of slough water dumped down storm drains enters the slough and mudflats and • 1 pitcher of slough water travels through the food chain, harming animals. • 12 glass petri dishes • 12 plastic microscope slides What can students do to help? • 12 hand lenses Refuge staff study pollutants found in the Bay to see how they • 12microspatulas affect wildlife, but we need your help. • 12 eyedroppers • Never dump anything down storm drains • 12 tripod magnifiers • Label storm drains with warnings • 4 containers of slough water • 1 plastic tub • Tell others what you have learned • 2 large microscopes • 6 student microscopes • 12 placemats with mud ID Provided by the Educator: • copies of data sheets (p. 192) and pencils, one per student (optional) Field Trip Activities- Habitat Studies 187 SUPPORTING INFORMATION fOR THIS ACTIVITY and nest in the pickleweed and cordgrass and feed on mud creatures in the mudflats. • Sloughs are "fingers" of San Francisco Bay. They • The diversity of mudflat plants and animals results are natural waterways connected to the bay and in a dynamic food pyramid. A food pyramid winding through the salt marsh. Because they are explains the loss of energy between different levels connected the bay, they are a tidal habitat. There of producers and consumers. are two high tides and two low tides each day. • Cordgrass (only at Visitor Center) and phy- • Mudflats appear in the slough channels and around toplankton (small, drifting plants) are produc- the edges of the bay when the tide flows out. ers. They support the entire food pyramid • Despite an apparent lack of plants and animals, because they use sunlight to make their own mudflats support an abundance of life. An esti- food or energy. mated 40,000 organisms live in a double handful of • Zooplankton (small, drifting animals) are the mud. first level of consumers. They feed on dead, • Many of these organisms are microscopic or decomposed cordgrass (detritus) and phy- nearly microscopic, such as ostracods, copep- toplankton. ods, and many different kinds of worms. • Worms, crabs, snails, mussels, and clams • In addition to microscopic organisms, larger, (the mud creatures) feed on the zooplankton, more visible animals inhabit the mudflats as phytoplankton, and detritus and represent the well, such as clams, mussels, snails, and crabs. second level of consumers. • When the mudflats are exposed at low tide, hun- • This is evident with birds (such as ducks, dreds of shorebirds and waterbirds of varying sizes shorebirds, and the California clapper rail), appear. They probe their beaks into the mud or which are the third level consumers, feeding on sweep them across the mud's surface in search of the mud creatures. food - the mud creatures. • A food pyramid always reaches a final level • Migratory ducks and shorebirds depend upon the where there are no additional natural predators. mudflats. They use the San Francisco Bay as a In this pyramid, humans and raptors (such as feeding and resting stop as they travel along the red-tailed hawks, northern harriers, and per- Pacific Flyway. egrine falcons) are the top level consumers, • The California clapper rail, an endangered species, feeding on the birds that use the mudflats. also depends upon the mudflats. Clapper rails hide MUDRAJ FOOD PYRAMID Top Level Consumers & Raptors x 3rd Level Consumers / California Clapper Rails, Ducks, Shorebirds / \d Level Consumers / ^ls' Mussels, Snails, Clams, Crabs ' 1st Level Zooplankton (small, drifting animals) Consumers ;U-3fPs'1? " M ^"^ / Producers / Cordgrass (detritus) and Phytoplankton 188 Field Trip Activities- Habitat Studies HOW TO LEAD THIS ACTIVITY BY FOLLOWING Do THE "DO, READ, ASK" TEACHING FORMAT Select volunteers to move the birds from the air and high marsh onto the mudflats. Mud Creature Banner (7 minutes) Do Ask Ask the students to sit at the table. ? What are these birds doing on the mudflats? Read (Looking for food.) "We are going to search for and study the creatures ? Are they eating mud? (No, they are eating that live in the bay mud. But first, let's look at the creatures that live in the mud.) birds that feed in the slough channel when the tide is low and the mudflats are exposed." Read "Despite an apparent lack of plants and animals, tidal Do mudflats support an abundance of life. An estimated The mud creature banner should be set to high tide, 40,000 organisms live in a double handful of bay with the mud creatures hidden behind the flaps on the mud." banner and the birds in the air or in the high marsh. Ask Read ? What do you think lives in the mud? (Accept "Sloughs are fingers of San Francisco Bay that cover all reasonable answers as possibilities.) the mudflats at high tide. Sloughs are affected by the tides because they are connected to the bay, which is Read connected to the ocean." "Let's find out what lives in the mud." "Look at this mud creature banner." Do Select volunteers to open up one flap at a time to Ask expose a mud creature and read the name of the Is it high tide or low tide on this banner? (It is creature. Help the students read the names. high tide because the slough is full of water.) Read Ask "These are some of the mud creatures we are going ? Why aren't the birds looking for food in the to be looking for. Most of these creatures are not slough? (The water is too deep to reach the crea- shown as their actual size." tures living in the mud at the bottom of the slough.) Mudflat Food Pyramid (3 minutes) Read Do "At low tide, when the water has returned to the bay, Hold up the food pyramid poster. the mudflats appear in the slough channels. Twice a day, the tide is low and the mudflats appear." Read "All food pyramids must have producers at the Do bottom. Remove the high tide fabric so that the banner is set • "Producers support the rest of the food pyramid. at low tide. Put the high tide fabric in the box labeled Detritus (decomposing plants) and phytoplankton "San Francisco Bay." (small, drifting plants) are the producers in the mudflats. Like all plants, they use sunlight to make Read food or energy. "When the mudflats are exposed (point out the • "Zooplankton (small, drifting animals) feed on mudflats sloping down from the marsh to the slough phytoplankton and detritus. They are the first water), hundreds of birds appear. They land on the consumer level. mudflats and probe into the mud with their beaks." Field Trip Activities- Habitat Studies 189 • "Mud creatures are the second consumer level - holes) on top and the finest screen (smallest holes) on they feed on zooplankton, phytoplankton, and the bottom. detritus. • "Birds (such as ducks, shorebirds, and California Read clapper rails, an endangered species) eat the mud "Now we are going to be searching for zooplankton creatures. They are the third level consumers. (first consumer level) and mud creatures (second • "Animals at the top level of a food pyramid have no consumer level). I need a volunteer to place a "golf- natural predators. In this food pyramid, humans ball" size mud sample on the top sieve and carefully and birds of prey (such as northern harriers, red- loosen it with your fingers." tailed hawks, and peregrine falcons, an endangered species) feed on the birds." Do Student puts on a glove before loosening the mud. Ask ? Why are mud creatures important? (They Read provide an important source of food for birds.) "I need another volunteer to pour slough water over the mud." ? Do you think mudflats are important to preserve? (Possible answers: Mudflats provide a Do home and food for many animals, including birds such • When the mud has passed through the top screen, as the California clapper rail, an endangered species. separate the sieves and pass them out to the Humans also eat ducks that feed on mud creatures.) students. ? What happens when pollution is dumped • Students should examine the sieves for animals.