CHAPTER 13Biological Productivity and Energy Transfer

Fig. 13.5

Primary productivity Rate at which energy is stored in

organic matterPhotosynthesisPhotosynthesis using solar radiation○ 99.9% of marine life relies directly or

indirectly on photosynthesis for food

ChemosynthesisChemosynthesis using chemical reactions Happens in hydrothermal vents at bottom of

ocean with no light

Let’s talk about energy Biological organisms need biochemical

processes to happen in an orderly fashion in order to maintain life○ Needs constant input of energy to maintain

that order○ Our cells need energy in form of ATP

ATP formed during cellular respirationNeed input of carbon (i.e. glucose) and oxygen for

cellular respirationThat carbon source and oxygen comes from

photosynthesis (primary productivity)

Photosynthetic productivity Chemical reaction that stores solar

energy in organic molecules○ Photosynthetic organisms fix carbon and

energy from atmosphere- Also incorporate other elements and

molecules necessary for life (nitrogen, phosphorus, etc)- What do we need these for? For making

proteins, lipids, DNA, etc.

- Use some of that for their own energy source for life- Rest moves it’s way up the food chain

Measuring primary productivity Capture plankton

Plankton nets Ocean color

ChlorophyllChlorophyll colors seawaterSeaWiFs on satellite

Factors affecting primary productivity NutrientsNutrients

Nitrate, phosphorous, iron, silicaNitrate, phosphorous, iron, silicaMost from river runoffProductivity high along continental margins

Solar radiationSolar radiationUppermost surface seawater and shallow

seafloorEuphotic zone surface to about 100 m (330

ft)

Upwelling and nutrient supply

Cooler, deeper seawater nutrient-rich Areas of coastal upwelling sites of high

productivity

Fig. 13.6ahttp://cordellbank.noaa.gov/images/environment/

upwelling_470.jpg

Light transmission

Visible light of the electromagnetic spectrum

Blue wavelengths penetrate deepest Longer wavelengths (red, orange)

absorbed first

Light transmission in ocean Color of ocean ranges

from deep blue to yellow-green

FactorsWater depth Turbidity from runoffPhotosynthetic pigment

(chlorophyll)○ “dirty” water in coastal

areas, lagoons, etc. are areas of high productivity, lots of plankton (preventing that “blue” color)

http://lh4.ggpht.com/_lQw_uDjiHTw/R7AmR74EByI/AAAAAAAAL40/VKg0nZ_Ih6c/DSC_0009.JPG

http://upload.wikimedia.org/wikipedia/commons/a/a5/LightningVolt_Deep_Blue_Sea.jpg

Types of photosynthetic marine organisms AnthophytaAnthophyta

Seed-bearing plants, example is mangroves

Macroscopic (large) algaeMacroscopic (large) algaeLarger seaweeds, like kelpLarger seaweeds, like kelp

Microscopic (small) algaeMicroscopic (small) algaephytoplanktonphytoplankton

Photosynthetic bacteriaPhotosynthetic bacteria

Anthophyta

Only in shallow coastal waters

Primarily seagrassesseagrasses & MangrovesMangroves

Very few plant species can tolerate salt water

http://celebrating200years.noaa.gov/events/sanctuaries/seagrass_meadow650.jpg

Macroscopic algae – “Seaweeds” Brown algaeBrown algae

http://oceanexplorer.noaa.gov/explorations/02sab/logs/aug09/media/lines_600.jpg

http://www.starfish.ch/photos/plants-Pflanzen/Sargassum.jpg

Sargassum

Green algaeGreen algae

Macroscopic algae – Macroscopic algae – “Seaweeds”“Seaweeds”

http://www.sms.si.edu/IRLspec/images/cbrachypus2.jpg

Caulerpa brachypus, an invasive species in the Indian River Lagoon

http://192.107.66.195/Buoy/System_Description_Codium_Fragile.jpg

Codium

Macroscopic algae – “Seaweeds”

Red algaeRed algae Most abundant and most

widespread of “seaweeds”Varied colors

http://www.dnrec.state.de.us/MacroAlgae/information/Indentifying.shtml

http://www.agen.ufl.edu/~chyn/age2062/lect/lect_15/22_14B.GIF

Microscopic algae Produce food for 99% of

marine animals Most planktonic

Golden algaeGolden algaeDiatomsDiatoms (tests of silica)

○ Most abundant single-celled algae – 5600+ spp.

○ Silicate skeletons – pillbox or rod-shaped ooze

○ Some w/ sticky threads, spines slows sinking

www.bren.ucsb.edu/ facilities/MEIAF

http://biologi.uio.no/akv/forskning/mbot/images

Microscopic algae

CoccolithophoresCoccolithophores (plates of ate)○ Flagellated○ calcium carbon plates possibly sunshades○ Coccolithid ooze fossilized in white cliffs of

Dover

http://www.esa.int/images http://epod.usra.edu/archive/images/coccolith.jpg

Microscopic algae DinoflagellatesDinoflagellates

Mostly autotrophic; some heterotrophic or both Flagella in grooves for locomotion Many bioluminescent Often toxic

○ Red tides (algal blooms) fish kills (increase nutrients, runoff)

Karenia spp., the alga that causes red tidehttp://www.hku.hk/ecology/porcupine/por24gif/Karenia-digitata.jpghttp://oceanworld.tamu.edu/students/fisheries/images/

red_tide_bloom_1.jpg

Manatees died in Brevard and Volusia counties in 2007, and on west coast, possibly due to red tide concentrates on

seagrass manatees eat

Breath in toxic fumes

http://www.nepa.gov.jm/yourenv/biodiversity/Species/gifs/manatee.jpg

Microscopic algae DinoflagellatesDinoflagellates

Pfiesteria in temperate coastal waters

Ciguatera (from) Gambierdiscus toxicus in tropical fishes

Paralytic, diarhetic, amnesic shellfish poisoning Pfiesteria

http://www.odu.edu/sci/biology/pfiesteria

http://www.hrw.com/science/si-science/ biology/plants/algae/ images/Gambitox.jpghttp://www.slv2000.qc.ca/bibliotheque/lefleuve/vol11no5/images_f/

alexandrium1.jpg

Gambierdiscus

Alexandrium – paralytic shellfish Alexandrium – paralytic shellfish

Photosynthetic bacteria Extremely small May be responsible for half of

total photosynthetic biomass in oceans

http://silicasecchidisk.conncoll.edu/Pics/Other%20Algae/Blue_Green%20jpegs/

Gloeocapsa_Key45.jpg

Gleocapsa

http://www.micrographia.com/specbiol/bacteri/bacter/bact0200/anabae03.jpg

Anabaena

Regional primary productivity Varies from very low to very high depending

onDistribution of nutrientsDistribution of nutrientsSeasonal changes in solar radiationSeasonal changes in solar radiation

About 90% of surface biomass decomposed in surface ocean

About 10% sinks to deeper oceanOnly 1% organic matter not decomposed in deep

ocean reaches bottomBiological pump (CO2 and nutrients to sea floor

sediments)

Table 13.1

= 4785Smaller than land but this is by meter2(think about how large ocean is compared to land)

= 6450

Temperate ocean productivity

Seasonal variation with temperature/light/nutrients Winter:

○ High winter winds mixing of sediments/plankton○ Low light & few phytoplankton nutrients increase

Spring: ○ Phytoplankton blooms with more light, nutrients○ Bloom continues until…

Nutrients run out Herbivores eat enough phytoplankton

Summer: often low production due to lack of nutrients

Fall: Often second bloom, as winds bring up nutrients

Polar ocean productivity Winter darkness Summer sunlight (sometimes 24

hours/day) Phytoplankton (diatoms) bloom Zooplankton (mainly small crustaceans)

productivity follows HIGH PRODUCTIVITY!! Example

Arctic Ocean

Fig. 13.13

Polar ocean productivity Availability of sunlight

during summer and High nutrients due to

upwelling of North Atlantic Deep WaterNo thermocline No barrier to vertical mixing

Blue whales migrate to feed on maximum zooplankton productivity

Tropical ocean productivity Permanent thermocline is barrier to vertical

mixing Low rate primary productivity (lack of nutrients)

above thermocline○ That’s why tropical waters tend to be clear and blue

Tropical ocean productivity Productivity in tropical ocean is lower

than that of polar oceans That’s why tropical oceans look clear Tropical oceans are deserts with some

high areas of sporadic productivity (oasis)

Equatorial upwellingEquatorial upwellingCoastal upwelling (river runoff, etc.)Coastal upwelling (river runoff, etc.)

Coral reefsCoral reefs

Energy flow in marine ecosystems ConsumersConsumers eat other organisms

Herbivores (primary consumers)CarnivoresOmnivoresBacteriovores

DecomposersDecomposers breaking down dead organisms or waste products

Nutrient flow in marine ecosystems Nutrients cycled from

one chemical form to another

BiogeochemicalBiogeochemical cyclingExample, nutrients fixed

by producersPassed onto consumersSome nutrients released

to seawater through decomposers

Nutrients can be recycled through upwelling

Feeding strategies Suspension feeding Suspension feeding

or filter feedingor filter feedingTake in seawater and

filter out usable organic matter

Deposit feedingDeposit feedingTake in detritus and

sediment and extract usable organic matter

Carnivorous feedingCarnivorous feedingOrganisms capture and

eat other animals

Trophic levels

Feeding stage is trophic leveltrophic level

Chemical energy is transferred from producers to consumers

On average, about 10% of energy is transferred to next trophic level

Much of the energy is lost as heat

Fig. 13-18

Food chain Food web Primary producer Herbivore One or more

carnivores

Branching network of many consumers

Consumers more likely to survive with alternative food sources

http://users.aber.ac.uk/pmm1

Food webs are more complex & more realistic Consumers often operate at two or more

levels

http://www-sci.pac.dfo-mpo.gc.ca/mehsd/images/ross_photos

Biomass pyramid

Both number of individuals and total biomass (weight) decrease at successive trophic levels

Organisms increase in size

Fig. 13.21

Symbiosis Organisms

associate in beneficial relationshipCommensalismCommensalism○ One benefits without

harm to otherMutualismMutualism○ Mutually beneficial

ParasitismParasitism○ One benefits and

may harm the other

Commercial fishing

Most tonnage from continental shelves and coastal fisheries, compared to open ocean fisheries

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

Fig. 13.23

Marine fisheries

Overfishing Taking more fish than is

sustainable over long periods Remaining fish younger,

smaller About 30% of fish stocks

depleted or overfished About 47% fished at biological

limit

http://www.fao.org/docrep/009/y5852e/Y5852E12.jpg

State of exploitation of selected stock or species groups for which assesment information is available, by major marine fishing areas, 2004

http://www.fao.org/docrep/009/y5852e/Y5852E08.jpg

Figure A2.4 - Stage of development of the 200 major marine fishery resources: 1950–2000

Aquaculture becoming a more significant component of world fisheries

http://www.fao.org/docrep/009/y5852e/Y5852E02.jpg

Marine fisheries leveling off over last 10-15 years

Figure 13.26

Incidental catch or bycatch BycatchBycatch - - Non-commercial

species (or juveniles of commercial species) taken incidentally by commercial fishers

Bycatch may be 25% or 800% of commercial fishBirds, turtles, dolphins,

sharks

http://gristmill.grist.org/images/admin/By_Catch_On_Boat.jpg

http://www.motherjones.com/news/featurex/2006/03/bycatch_265x181.jpg

http://www.int-res.com/uploads/pics/esrspecial-bycatch_01.jpg

Incidental catch or bycatch Technology to help reduce

bycatchDolphin-safe tunaTEDs – turtle exclusion devices

Driftnets or gill nets banned in 1989 Gill nets banned in Florida by

constitutional amendment in 1994

http://ourworld.compuserve.com/homepages/CVisco/tuna.gif

http://www.st.nmfs.noaa.gov/st4/images/TurtTEDBlu_small.jpg http://www.teara.govt.nz/NR/rdonlyres/A5B74D1E-5BD8-4D7B-B75D-F1480DC74C5D/207170/p6281atl.jpg

Fisheries management Regulate fishing

Closings – Cod fisheries of New England

SeasonsSize limits○ Minimum size limits –

protects juveniles, less effective

○ Min/max size (slot) limits – preserves juvs and larger adults (contribute most reproductive effort)

http://www.cefas.co.uk/media/70062/fig10b.gif

http://www.cefas.co.uk/media/70037/fig7b.gif

Plaice

Fisheries management Conflicting interests

Conservation vs. economic – “tragedy of the commons”

Self-sustaining marine ecosystems

Human employmentInternational watersEnforcement difficult

“Tragedy of the commons” – All participants must agree to conserve the commons, but any one can force the destruction of the commons http://farm1.static.flickr.com/

178/380993834_09864a282c.jpghttp://dieoff.org/page109.htm

Fisheries management Governments subsidize

fishingMany large fishing vessels –

often purchased with economic stimulus loans

1995 world fishing fleet spent $124 billion to catch $70 billion worth of fish

http://newsroom.nt.gov.au/adminmedia/mailouts/3879/attachments/Indonesian

%20fishing%20boat%202.JPG

34m Fishing Vessel Apprehended In Australian Waters, April 2008

Activists deploying a banner reading, 'No Fish No Future' next to tuna fishing vessel Albatun Tre, which they claim is the world's largest tuna fishing vessel

http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/05/30/eatuna130.xml

Fisheries management Northwest Atlantic

Fisheries such as Grand Banks and Georges Bank

Canada and U.S. restrict fishing and enforce bans

Some fish stocks in North Atlantic rebounding

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

http://yukna.free.fr/science/zebramussels/300px-Grand_Banks.png

http://content.answers.com/main/content/wp/en/thumb/7/7d/300px-GulfofMaine.jpg

Fisheries management Consumer choices in seafood Consume and purchase

seafood from healthy, thriving fisheriesExamples, farmed seafood,

Alaska salmon

Avoid overfished or depleted seafoodExamples, bluefin tuna, shark,

shrimp, swordfishVisit: ORCA's Blue Diet page

http://marineresearch.ca/hawaii/wp-content/uploads/tuna-auction-largeview.jpg

Figure 13.28