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EcosystemEcologyI:EnergyandNutrientsTodaysquestions:I. Howdoesenergymovethroughecosystems?II. Howdonutrientsmovethrou hecos stems?

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I. Howdoesenergyflowthroughecosystems?A.PatternsinnetprimaryproductivityI

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1. WhereisNPP/km2 particularlyhigh?

2. WhyisNPP/km2 intheopenoceansolow,iflotsof

3.WhydoessomuchofthetotalNPPcomefromtheopenocean?

In agal sea areas (by the coast line). Rainforest and coral reefs.

There aren't enough nutrients in the ocean.

Because the open ocean covers a large part of the earth (has a large

surface area).

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Patternsin

net

primary

productivity

II

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4.Arethedataonthemapconsistentwiththedatainthebarcharts?Explainanydiscrepancies.

5.Whatlimitsproductivityinterrestrialhabitats?Temperature and water.

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6.In

the

open

ocean,

what

happens

to

nutrients

available

inorganismslivingatthesurface?

. ,thebenthos?

8.Whataretheprosandconsoffertilizingtheopenocean?Pros: Negative feedback. There are more nutrients so NPP goes up, and CO2 will

go down and O2 will go up.

Cons: Not sure what will happen to the biomass. What happens when we put a

bunch of things at the bottom of the ocean?

They're being used up very quickly by photosynthesis. When the photosynthetic

organisms died, the nutrients from their body sink to the bottom.

Away from the coastal areas, the ocean is so deep that there's no physical

mechanism (no up-dwelling) to bring the nutrient back up.

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B.WhathappenstoNPP?1,254,000kcal/m2/yrinsunlight

10,032kcal/m2/yrcapturedbyphotosynthesis(0.8%)

4,514kcal/m2/yr 5,518kcal/m2/yrto

, ca m yr , ca m yrtoconsumers todecomposersWhatpercentageofNPPgetseatenaslivingtissue?

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C. Tro hic levels in a food chain or food webTrophic

eve ee ngs ra egy raz ng oo c a n5 40 consumer Orcas4 30 consumer Salmon3 20 consumer Herring,candlefish,other

1 Autotroph Photosyntheticalgae&bacteria,

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D.Efficiency

of

energy

transfer

at

Hubbard

Brook

3gramsoftertiaryconsumer(~10%efficiency)~

~1%ofincidentsunlighttoprimaryproduction

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8.Whyissomuchenergylostateachtransfer?

9.Whichismoreefficientasaprimaryconsumer,afishoracow?Wh ?

10.Clamsandmusselseatdetritusaswellassmall.

themanefficientconsumer?

Takes energy to make energy. Everything not used for growth or reproduction

or maintenance (movement, breathing, repair of tissue, defense) or excreted

is what is passed on, but by then, the amount is typically small.

Fish because they spend less energy on maintenance. Not burning calories to

maintain body heat.

Probably more efficient because they can gather from more sources.

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. w u w u y

movethroughecosystems,fromorganismtoorganisminfoodwebsandto/fromtheabiotic environment(water,soil,atmosphere)

Humansarealteringmostbiogeochemicalcyclesin

e. .alterin thenitro enc cle

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Wh does a dead zone form in Hood Canal?1. Insummer,growthofalgaeandphotosynthetic

.2.Whentheseorganismsdie,

Whataresomepossiblesolutions?

They sink, decomposition

takes up the oxygen, so it

becomes an oxygen poor zone

(anaerobic "dead zone").