• Read the Elementary GLOBE book Discoveriesat Willow Creek – either read it to the class orhave students read it to themselves. The bookcan be downloaded from www.globe.gov/elementaryglobe.
Part 1: •Prepare overhead transparencies of illustrations/
photographsofseveraldifferentmacroinvertebrates.Youcaneithercopytheillustrationsprovidedattheendofthisactivity(WaterWondersFieldCards),ormakecopies from the followingWebsites:www.people.virginia.edu/%7Esos-iwla/Stream-Study/Key/MacroKeyIntro.HTML or www.dec.state.ny.us/website/dow/stream.
•Make one copy of the Water Wonders StudentActivitySheet1foreachstudent.
Part 2:•Create a classroom aquarium with aquatic
macroinvertebrates. To setup theaquarium,putabout five centimeters of sand in the bottom ofa tank. Use water from a pond or stream to filltheaquarium. Ifyouusetapwater instead, let itstandforafewdaysintheaquariumbeforeaddinginsects. Plant some small aquatic plants or putsomealgae(greenpondscumplants)inthetank.Cover theaquariumwithaglassor screen top tokeepflyingaquaticinsectsfromescaping.
•Addathermometertothewateroftheaquarium.Make sure the temperature graduations on thethermometerareclearenoughforyoungstudentsto read. Studentsmightneedassistance readingthethermometeratfirst.
•Make one copy of the Water Wonders StudentActivitySheet2foreachstudentforeachtimetheywillbemakingobservationsoftheaquarium.
•One supplier of aquatic macroinvertebrates isCarolina Biological Supply (www.carolina.com).
They sell a water insect collection, as well asindividual speciesof aquatic insects. Also, somesupplierssellcrustaceanslikecrayfish,shrimp,etc.and these would be interesting for students toobserveaswell. (Macroinvertebratesarenot justinsects,thoughaquaticinsectsarethefocusofthisactivity.SeetheTeacher’sNotessectionformoreinformation.)
•Note: If you decide to collect macroinvertebratesinastreamorpondonyourown,makesureyoucomply with regulations in your local area aboutplantandanimalcollections.SomeguidelinesforthiscanbefoundintheFieldCollectionofLivingOrganismsarticleonthefollowingWebsite:www.carolina.com/tips/95jan/fcolo.asp
•Note:ifyouhavealargeenoughbudget,theready-madeRiverTankEcosystemisagreatwaytosetupaclassroomaquariumtostudymacroinvertebrates.For more information about this product, go towww.rivertank.com.
•Note: some of the macroinvertebrates and theirlarvae may be predaceous (they feed on otherinsects), so you may have to keep restockingthe aquarium. Pollywogs are food for somepredaceousinsects.Also,awordofwarning:whenmacroinvertebratesarekepthappyandhealthy,theywillmorphintoadultsthatliveoutofthewater.Beawareofthiswhenaddingblackflyorbitingmidgelarvaetoyourtank!
•For more information about maintaining aclassroomaquarium,seetheProjectWILDAquaticK-12Curriculum&ActivityGuide(www.projectwild.org).
Teacher’s Notes
IntheElementaryGLOBEbookDiscoveriesatWillowCreek, theGLOBE studentsdiscusshow they foundaquaticinsectsinthestreamwhentheyvisiteditforthefirsttime.Theylearnthattheycan’tseeanyonthesecondvisitbecauseitwastooearlyinthespringand the water levels were too high and the watertemperaturewastoocold.Studyingmacroinvertebratesissomethingyoungerelementarystudentsenjoyand
is a way to introduce them to hydrology concepts,including the idea that macroinvertebrates indicatewaterquality.
Macroinvertebrates are small animals without abackbonethatcanbeseenwithoutamicroscope.Theylivearoundlivingordeadvegetation,onthesurfaceorinthesedimentsofwaterbodies.Theyincludemanylarvaeofinsectssuchasmosquitoes,dragonfliesandcaddisfliesthatbegintheirlivesinthewaterbeforebecoming landdwelling insectswhen theymature.Other examples of common macroinvertebratesincludecrustaceans(suchascrayfish),snails,wormsandleeches.Macroinvertebratescanpopulatepondsorstreamsinamazingnumbers–someofthemuptothousandsinasquaremeter.Theyareanimportantpartofthefoodchain.
Macroinvertebrates can tell us a lot aboutthe conditions within a water body. Manymacroinvertebrates are sensitive to changes in pH,dissolvedoxygen,temperature,salinity,transparencyandotherfluctuationsintheirhabitat.Ahabitatisaplacethatincludeseverythingthatananimalneedstoliveandgrow.Itincludesfoodresourcesandthephysical characteristics of the environment, as wellas places and materials to build nests, raise youngandkeepthemsafefrompredators.Habitatsincluderocks,sticks,deadanddecayingvegetationandotherlivingorganismssuchasplants.
Macroinvertebrate samples allow us to estimatebiodiversity,examinetheecologyofthewaterbodyand explore relationships among water chemistrymeasurementsandorganismsatastreamorpond.
For more information on hydrology and aquaticmacroinvertebrates,herearesomeresourcesyoucanuse:
•The Hydrology section of the GLOBE Teacher’sGuide(www.globe.gov)
•WOW!TheWondersofWetlands,byEnvironmentalConcern, Inc. and The Watercourse (www.projectwet.org)
What To Doand How To Do It
Part 1: Introduction toMacroinvertebrates1.After reading the Elementary GLOBE book
DiscoveriesatWillowCreekwithyourstudents,talkto themabout themacroinvertebratesmentionedinthebook.Gatherthestudentstogetherandtellthemthattheywillbestudyingmacroinvertebrates,or water critters, that live in ponds and streams.Then show them enlarged versions of the WaterWondersFieldCards.
3.As you show the different illustrations to thestudents,askthemtothinkaboutwhyeachcritterlooksthewayitdoes.Havethemlookatthecritter’sshape,presenceorabsenceofgills,numberandplacementoflegs,antennae,tails,etc.
4.Pass out copies of the Water Wonders StudentActivitySheet1.Havethestudentsselectawaterinsect illustration to look atmore closely so theycanfillouttheiractivitysheet.Youmightwanttopassoutextraphotocopiesof theWaterWondersFieldCardsforthestudentstouseatthispoint.
Part 2: Classroom Aquarium1.Showthestudentstheclassroomaquarium.Note
that the aquarium may look different to thembecause ithasmacroinvertebrates in it insteadoffish.
2.Tellthestudentsthattheywillmakeobservationsofthedifferentwaterinsectsoverthenextfewweeks.Each time they make observations, they can alsorecordthewatertemperatureintheaquarium.
3.Dividethestudentsintogroupsof3-4studentsandhavethemspendsometimemakingobservationsabout the macroinvertebrates in the aquarium.Encourage the students to watch the differentcritters’behavior.Theycanusethequestionslisted
6.At theendof thisobservationperiod,gather thestudentsforaclassdiscussion.Askthemtosharewhat they learned about the macroinvertebratesand record their responsesonchartpaper. TheycanusetheWaterWondersStudentActivitySheet1theyfilledoutatthebeginningofthislessontohelpthemmakeconclusionsaboutwhattheyhavelearned.
7.See the “Adaptations for Younger and OlderStudents”sectionofthisactivityforideasofwaterqualityactivitiesyoucandowiththeaquarium.
Part 3: Optional Field TripNote:ifthereisanaccessiblestreamorpondnearyourschool,itisawonderfulexperiencetotakestudentstothestream/pondtoinvestigatemacroinvertebratesinthewild.Youcancombinethistripwithotherhydrologyinvestigations. Belowaresome ideasofwhat todowithyourstudentsatthestream/pond.
1.Remind your students about safety issues beforevisitingthestream/pond.
2.Some supplies you shouldbring to the field site:dipnets,plasticcontainers forholdingwaterandcollected organisms, magnifying lenses, rulers,journals, pencils, towels, paper towels, fieldguides,andlaminatedsheetswithinformationon
macroinvertebrates.
3.When you arrive at the stream/pond, have thestudentsfirstusetheirsenses;theycanlisten,see,smell,andtouchthestreamenvironmentandthenrecordtheseobservationsintheirjournals.
4.Next,withadultassistance,havestudentswadeinthe stream safely and collect macroinvertebratesusing a net. Then sort and identify the indicatorspeciesusingapictorialidentificationkey.Formoreinformationonindicatorspecies,seethe“FurtherInvestigations”sectionofthisactivityonpage5.
5.Point out unique characteristics of each species,including their shape, size, movement, andbehavior.
6.Ifitfitsinwithyourstudents’abilitylevel,performtestson thepondor streamwater. Some thingsyoucantestare:dissolvedoxygen,nitrates,waterpH,watertemperature,andstreamflow.
7.After the field trip, have the students write asentence and/or draw a picture about what theysaw,smelled,heard,orfeltontheirtrip.
8.Formoreinformationonstudyingmacroinvertebratesin streamsandponds, see theGLOBEFreshwaterMacroinvertebratesProtocolintheGLOBETeacher’sGuide(www.globe.gov).
Adaptations for Youngerand Older Students
For younger students: Have each student selecta macroinvertebrate and write several descriptivesentences about the characteristics of this “watercritter.” Somestudentswillneedtohaveanadulthelpthemwiththis.Thestudentscanalsodrawthemacroinvertebrates.Haveeachstudentsharehisorherinformationwiththeclass.
Olderstudentscanconductvarioustestsonthewaterin the aquarium, including testing the water pH,dissolvedoxygenlevels,nutrientlevels,etc.Youngerstudentscanpairupwithmiddleorsecondaryschoolstudentswhoarestudyinghydrology to learnmoreaboutwaterqualitytests.
Questions to ask when observing the aquaticinsects:1.Howdoestheinsectmove?2.Whatshapeisit?3.Whatcolorisit?4.Whatdoestheinsecteat?5.Doesanythingpreyuponit?6.Isitalarva,oranadult?
Older students can use a MacroinvertebrateDichotomous Key to identify unknownmacroinvertebrates. The following Web site hasa key you can use: www.dec.state.ny.us/website/dow/stream/. You can also find other keys on theWorldWideWeboratyour local library. Also,haveolder students look at macroinvertebrates under amicroscopetolearnmoreabouttheiranatomy.
Further Investigations
•Life Stories of Macroinvertebrates: Have thestudentseach select a specificmacroinvertebratethat they have observed. Based on what theylearnedaboutthisinsectinclass,havethestudentswrite a story about the life of this organism. Ifpossible, the students candoadditional researchfortheirstories.
•Water Quality Studies: Explain to the studentsthat macroinvertebrates are what scientists callan indicator species. This means that certainmacroinvertebrates can tolerate higher levels ofpollutantsinthewater,whileotherscannottoleratepollutantsatall.Learnwhichcrittersarepollutiontolerant,somewhattolerant,orpollutionsensitive.Basedonthecrittersyoufindinastreamorpond,youcandetermineif thewaterquality isgoodornot;thishelpsstudentsunderstandhowsamplingaquatic macroinvertebrates helps determinewhetherthewateriscleanandsafe.Thefollowingweb site provides information: www.epa.gov/bioindicators/html/benthosclean.html.
•Community History:Havethestudentstalktooldermembersofthecommunitywhohavelivedthereall their lives. They can talk to family members,residentsataseniorcenter,etc.Afteraskingthecommunity members to describe what the localstreams and ponds were like when they wereyoung, the students can learn how the stream/pondhaschangedovertheyears.
•Water Walk Learning Activity: This activity canbe found in the Hydrology chapter of the GLOBETeacher’sGuide(www.globe.gov).
•Hydrology Investigations:Basedonyourstudents’knowledgeandabilitylevels,conductthedifferentHydrology Protocols with your students. See theGLOBETeacher’sGuideformoreinformation(www.globe.gov).
