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Water Quality Degradation in the Ocean Answer Key
Use the following online resources to answer the questions. • NationalGeographic“DeadZone”encyclopedicentry• WoodsHoleOceanographicInstitution“HarmfulAlgae”site.The“Impacts”tabwillalsoprovide
helpfulinformation.
Part 1. HarmfulAlgalBlooms(HABs) 1.Whatarephytoplankton? _____________________________________________________________
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2.WhatareHarmfulAlgalBlooms(HABs)? ________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________
3.WhataresomeofthenegativeeffectsofHABformation? _________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________
Part 2.ToxicAlgae 4.DescribetherelationshipbetweenHABsandtoxicphytoplankton. _________________________
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5.Whatisbiomagnification? ____________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________
6.DescribetherelationshipbetweenHABsandshellfishpoisoning. __________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________
Phytoplankton,oralgae,areaquatic,photosyntheticorganismsthatfloatatordriftbelowthewatersurface.Theyformthebaseoftheaquaticfoodwebandaffectthechemicalprocessesofphotosynthesis,respiration,anddecompositionoccurringinaquaticecosystems.
Harmfulalgalblooms(HABs)aredenseaccumulationsofphytoplankton,oralgae,thathavenegativeimpactsonother organisms.
HABscancausethereleaseoftoxinsthatleadto:sicknessanddeathofbirds,dogs,andotheranimals;poororunsafewaterqualityconditions;andhumanillness.SomeHABshaveothernegativeeffects,includingwatercolorchanges,waterodor,andhypoxia.
HABscontainspecifictypesofphytoplanktonthatproduceandreleasetoxins.Thesetoxinscanbedirectlyingestedbyorganismsorbiomagnifiedupthroughlevelsofthefoodchain,wheretheybecomeevenmoretoxic.
Biomagnificationisaresultoftheaccumulationofphytoplanktontoxinsathigherandhighertrophiclevelsofthefoodchain.
Toxinscanaccumulatequicklyinshellfishduetotheiruseoffilterfeeding,inwhichlargevolumesofwaterarefilteredtoconsumehighconcentrationsofphytoplankton.Ifthephytoplanktonconsumedaretoxic,thentheshellfishcanbioaccumulatethattoxin.
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Water Quality Degradation in the Ocean Answer Key, continued
7.BrieflydescribeonecurrenteventrelatedtotoxicalgaewithintheUnitedStates. ____________ ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________
8.Brieflydescribeonecurrenteventrelatedtotoxicalgaeoutside oftheUnitedStates. ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________
Part 3. DeadZones 9.DescribetherelationshipbetweenHABsandeutrophication,ornutrientloading.
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10.Whatisadeadzone? ________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________
11.DescribetherelationshipbetweenHABsandhypoxia,oroxygendepletion. ________________ ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________
12.BrieflydescribeonewaterqualityimprovementsuccessstorywithintheUnitedStates. ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________
Answerswillvary.
Answerswillvary.
Answerswillvary.
EutrophicationduetoexcessnutrientrunoffandcyclingwithinthewatercolumnincreasesnutrientavailabilitytophytoplanktonthatcompriseHABs.Whenphytoplanktonhaveplentyofnutrientstosustainthemandtheyarenotnutrient-limited,theycanbloom,aslongastheirotherrequirements(light,temperature)arebeingmet.
Adeadzoneisahypoxic,orlowoxygen,areainanaquaticecosystemthatcandepriveorganismsoftheoxygenneededforrespiration.Thiscanleadtofishkillsand,eventually,anoxic(withoutoxygen)conditionsunabletosupportlife.
HypoxiacanresultwhenincreasedphytoplanktonbiomassfromHABsbeginstodieandisdecomposedbybacteria.Thebacteriarespireanddepletethewaterofoxygen.Althoughphytoplanktonarephotosynthesizing,therespirationrates(ofbacteriaandphytoplanktonatnight)aregreaterthanphotosynthesisrates,leadingtohypoxia.