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