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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.