CHAPTER 13CHAPTER 13Biological Productivity and Energy Biological Productivity and Energy

TransferTransfer

Fig. 13.5

Primary productivityPrimary productivity

Rate at which energy is stored in Rate at which energy is stored in organic matterorganic matter

PhotosynthesisPhotosynthesis using solar radiation using solar radiation ChemosynthesisChemosynthesis using chemical using chemical

reactionsreactions 99.9% of marine life relies directly or 99.9% of marine life relies directly or

indirectly on photosynthesis for foodindirectly on photosynthesis for food

Photosynthetic productivityPhotosynthetic productivity Chemical reaction that stores solar Chemical reaction that stores solar

energy in organic moleculesenergy in organic molecules

Fig. 13.1

Photosynthetic productivityPhotosynthetic productivity Gross primary productionGross primary production

Total amount of organic carbon produced Total amount of organic carbon produced by photosynthesis per unit time in certain by photosynthesis per unit time in certain areaarea

Net primary productionNet primary production Gross primary production minus cellular Gross primary production minus cellular

respiration (growth, reproduction)respiration (growth, reproduction) New productionNew production

Nutrients added to local ecosystem (e.g., Nutrients added to local ecosystem (e.g., upwelling)upwelling)

Regenerated productionRegenerated production Recycling of nutrients within ecosystemRecycling of nutrients within ecosystem

Measuring primary Measuring primary productivityproductivity

Capture planktonCapture plankton Plankton netsPlankton nets

Ocean colorOcean color ChlorophyllChlorophyll colors seawater colors seawater SeaWiFs on satelliteSeaWiFs on satellite

Factors affecting primary Factors affecting primary productivityproductivity NutrientsNutrients

Nitrate, phosphorous, iron, silicaNitrate, phosphorous, iron, silica Most from river runoffMost from river runoff Productivity high along continental Productivity high along continental

marginsmargins Solar radiationSolar radiation

Uppermost surface seawater and Uppermost surface seawater and shallow seafloorshallow seafloor

Euphotic zone surface to about 100 m Euphotic zone surface to about 100 m (330 ft)(330 ft)

Upwelling and nutrient Upwelling and nutrient supplysupply Cooler, deeper seawater nutrient-richCooler, deeper seawater nutrient-rich

Areas of coastal upwelling sites of high Areas of coastal upwelling sites of high productivityproductivity

Fig. 13.6a

Light Light transmissiontransmission

Visible light of the Visible light of the electromagnetic electromagnetic spectrumspectrum

Blue wavelengths Blue wavelengths penetrate deepestpenetrate deepest

Longer Longer wavelengths (red, wavelengths (red, orange) absorbed orange) absorbed firstfirst

Fig. 13.3

Light Light transmissiontransmission

Fig. 13.3

Light transmission in oceanLight transmission in ocean

Color of ocean ranges from deep Color of ocean ranges from deep blue to yellow-greenblue to yellow-green

FactorsFactors Turbidity from runoffTurbidity from runoff Photosynthetic pigment Photosynthetic pigment

(chlorophyll)(chlorophyll) EutrophicEutrophic OligotrophicOligotrophic

Light transmission in oceanLight transmission in ocean SeaStar satellite/SeaWiFS view of ocean SeaStar satellite/SeaWiFS view of ocean

chlorophyll and land vegetation (productivity)chlorophyll and land vegetation (productivity)

Fig. 13-5

Types of photosynthetic Types of photosynthetic marine organismsmarine organisms

AnthophytaAnthophyta Seed-bearing plantsSeed-bearing plants

Macroscopic (large) algaeMacroscopic (large) algae Microscopic (small) algaeMicroscopic (small) algae Photosynthetic bacteriaPhotosynthetic bacteria

AnthophytAnthophyta a

Only in shallow Only in shallow coastal waterscoastal waters

Primarily grasses Primarily grasses andand

Mangroves Mangroves

Fig. 13.7

Macroscopic algaeMacroscopic algae ““Seaweeds”Seaweeds” Brown algaeBrown algae Green algaeGreen algae Red algaeRed algae (most abundant and (most abundant and

most widespread)most widespread) Varied colorsVaried colors

Microscopic Microscopic algaealgae Produce food for 99% of marine animalsProduce food for 99% of marine animals Most planktonicMost planktonic Golden algaeGolden algae

Diatoms Diatoms (tests of silica) (tests of silica) Coccolithophores Coccolithophores (plates of calcium carbonate)(plates of calcium carbonate)

DinoflagellatesDinoflagellates

Red tide (harmful algal bloom)Red tide (harmful algal bloom)

ToxinsToxins

Fish killsFish kills

Human illnessHuman illness

Photosynthetic bacteriaPhotosynthetic bacteria

Extremely smallExtremely small May be responsible for half of May be responsible for half of

total photosynthetic biomass total photosynthetic biomass in oceansin oceans

Regional primary Regional primary productivityproductivity Varies from very low to very high Varies from very low to very high

depending ondepending on Distribution of nutrientsDistribution of nutrients Seasonal changes in solar radiationSeasonal changes in solar radiation

About 90% of surface biomass About 90% of surface biomass decomposed in surface oceandecomposed in surface ocean

About 10% sinks to deeper oceanAbout 10% sinks to deeper ocean Only 1% organic matter not decomposed Only 1% organic matter not decomposed

in deep oceanin deep ocean Biological pump (COBiological pump (CO22 and nutrients to sea and nutrients to sea

floor sediments)floor sediments)

Polar ocean productivityPolar ocean productivity Winter darknessWinter darkness Summer sunlightSummer sunlight Phytoplankton (diatoms) bloomPhytoplankton (diatoms) bloom Zooplankton (mainly small Zooplankton (mainly small

crustaceans) productivity followscrustaceans) productivity follows ExampleExample

Arctic OceanArctic Ocean

Fig. 13.13

Polar ocean productivityPolar ocean productivity Availability of sunlight andAvailability of sunlight and High nutrients due to upwelling of High nutrients due to upwelling of

North Atlantic Deep WaterNorth Atlantic Deep Water No thermocline No thermocline No barrier to vertical mixingNo barrier to vertical mixing

Blue whales migrate to feed on Blue whales migrate to feed on maximum zooplankton productivitymaximum zooplankton productivity

Fig. 13-11b

Tropical ocean productivityTropical ocean productivity Permanent thermocline is barrier to Permanent thermocline is barrier to

vertical mixingvertical mixing Low rate primary productivity (lack Low rate primary productivity (lack

of nutrients)of nutrients) High primary productivity in areas ofHigh primary productivity in areas of Equatorial upwellingEquatorial upwelling Coastal upwellingCoastal upwelling Coral reefsCoral reefs

Symbiotic algaeSymbiotic algae Recycle nutrients within the ecosystemRecycle nutrients within the ecosystem

Fig. 13.12

Temperate ocean Temperate ocean productivityproductivity Limited by both available sunlight andLimited by both available sunlight and Available nutrientsAvailable nutrients Highly seasonal patternHighly seasonal pattern

Winter low (lots of nutrients, little Winter low (lots of nutrients, little sunlight)sunlight)

Spring high (spring bloom)Spring high (spring bloom) Summer low (little nutrients, lots of Summer low (little nutrients, lots of

sunlight)sunlight) Fall high (fall bloom)Fall high (fall bloom)

Regional productivity Regional productivity summarizedsummarized

Fig. 13.14

Energy flow in marine Energy flow in marine ecosystemsecosystems Ecosystem includes living organisms Ecosystem includes living organisms

(biotic community) and environment(biotic community) and environment Solar energy converted to chemical Solar energy converted to chemical

energy by energy by producersproducers (mainly (mainly photosynthesis)photosynthesis)

ConsumersConsumers eat other organisms eat other organisms HerbivoresHerbivores CarnivoresCarnivores OmnivoresOmnivores BacteriovoresBacteriovores

DecomposersDecomposers breaking down dead breaking down dead organisms or waste productsorganisms or waste products

Algae-supported biotic Algae-supported biotic communitycommunity

Fig. 13.15

Nutrient flow in marine Nutrient flow in marine ecosystemsecosystems Nutrients cycled from one chemical Nutrients cycled from one chemical

form to anotherform to another BiogeochemicalBiogeochemical cycling cycling Example, nutrients fixed by producersExample, nutrients fixed by producers Passed onto consumersPassed onto consumers Some nutrients released to seawater Some nutrients released to seawater

through decomposersthrough decomposers Nutrients can be recycled through Nutrients can be recycled through

upwellingupwelling

Fig. 13.16

Biogeo-Biogeo-chemical chemical cyclingcycling

Feeding strategiesFeeding strategies Suspension feeding or filter feedingSuspension feeding or filter feeding

Take in seawater and filter out Take in seawater and filter out usable organic matterusable organic matter

Deposit feedingDeposit feeding Take in detritus and sediment and Take in detritus and sediment and

extract usable organic matterextract usable organic matter Carnivorous feedingCarnivorous feeding

Organisms capture and eat other Organisms capture and eat other animalsanimals

Feeding strategiesFeeding strategies

Fig. 13.17d

Trophic Trophic levelslevels

Chemical Chemical energy is energy is transferred transferred from from producers producers to to consumersconsumers

Feeding Feeding stage is stage is trophic trophic levellevel

About 10% About 10% of energy of energy transferred transferred to next to next trophic trophic levellevel

Fig. 13-18

Passage of energy between Passage of energy between trophic levelstrophic levels

Fig. 13.19

Food chainFood chain Food web Food web

Primary Primary producerproducer

HerbivoreHerbivore One or more One or more

carnivorescarnivores

Branching Branching network of many network of many consumersconsumers

Consumers more Consumers more likely to survive likely to survive with alternative with alternative food sourcesfood sources

Fig. 13.20

Biomass Biomass pyramidpyramid

Number of Number of individuals individuals and total and total biomass biomass decrease at decrease at successive successive trophic levelstrophic levels

Organisms Organisms increase in increase in sizesize

Fig. 13.21

SymbiosiSymbiosis s Organisms associate in beneficial Organisms associate in beneficial

relationshiprelationship CommensalismCommensalism

One benefits without harm to otherOne benefits without harm to other MutualismMutualism

Mutually beneficialMutually beneficial ParasitismParasitism

One benefits and may harm the One benefits and may harm the other other

Commercial Commercial fishingfishing

Most from Most from continental continental shelvesshelves

Over 20% from Over 20% from areas of areas of upwelling that upwelling that make up 0.1% of make up 0.1% of ocean surface ocean surface areaarea

Fig. 13.23

Marine Marine fisheriesfisheries

OverfishinOverfishing g Taking more fish than sustainableTaking more fish than sustainable Remaining fish young, smallRemaining fish young, small About 30% of fish stocks depleted or overfishedAbout 30% of fish stocks depleted or overfished About 47% fished at biological limitAbout 47% fished at biological limit

Fig. 13.24

Incidental catch or bycatchIncidental catch or bycatch Non-commercial species taken Non-commercial species taken

incidentally by commercial fishersincidentally by commercial fishers Bycatch may be 25% or 800% of Bycatch may be 25% or 800% of

commercial fishcommercial fish Birds, turtles, dolphins, sharksBirds, turtles, dolphins, sharks Dolphin-safe tunaDolphin-safe tuna

Driftnets or gill nets banned in 1989Driftnets or gill nets banned in 1989

Fisheries managementFisheries management

Regulate fishing Regulate fishing Conflicting interestsConflicting interests Human employmentHuman employment Self-sustaining marine ecosystemsSelf-sustaining marine ecosystems International watersInternational waters Enforcement difficultEnforcement difficult

Fisheries managementFisheries management

Many large fishing vesselsMany large fishing vessels 1995 world fishing fleet spent 1995 world fishing fleet spent

$124 billion to catch $70 $124 billion to catch $70 billion worth of fishbillion worth of fish

Governments subsidize fishingGovernments subsidize fishing

Fisheries managementFisheries management

Northwest Atlantic Fisheries such as Northwest Atlantic Fisheries such as Grand Banks and Georges BankGrand Banks and Georges Bank

Canada and U.S. restrict fishing and Canada and U.S. restrict fishing and enforce bansenforce bans

Some fish stocks in North Atlantic Some fish stocks in North Atlantic reboundingrebounding

Other fish stocks still in decline (e.g., Other fish stocks still in decline (e.g., cod)cod)

Fisheries managementFisheries management

Consumer choices in seafoodConsumer choices in seafood Consume and purchase seafood from Consume and purchase seafood from

healthy, thriving fisherieshealthy, thriving fisheries Examples, farmed seafood, Alaska Examples, farmed seafood, Alaska

salmonsalmon Avoid overfished or depleted seafoodAvoid overfished or depleted seafood

Examples, tuna, shark, shrimpExamples, tuna, shark, shrimp

End of CHAPTER 13 End of CHAPTER 13 Biological Productivity and Energy Biological Productivity and Energy

TransferTransferFig. 13.25