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Primary Productivity in the Marine Environment

Primary Productivity in the Marine Environment. Fig. 13.5. Primary productivity. Energy is converted into organic matter to be used by cells Photosynthesis using solar radiation 99.9% of marine life relies directly or indirectly on photosynthesis for food

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Primary Productivity in the Marine Environment

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  1. Primary Productivity in the Marine Environment Fig. 13.5

  2. Primary productivity • Energy is converted into organic matter to be used by cells • Photosynthesis using solar radiation • 99.9% of marine life relies directly or indirectly on photosynthesis for food • Chemosynthesis using chemical reactions • Happens in hydrothermal vents at bottom of ocean with no light

  3. Remember, energy cannot be created or destroyed – it only changes form

  4. 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 respiration • Need input of carbon (i.e. glucose) and oxygen for cellular respiration • That carbon source and oxygen comes from photosynthesis (primary productivity)

  5. 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 • Excess moves it’s way up the food chain

  6. Now we are going to revisit photosynthesis and cellular respiration • Remember, we are following electrons and protons • OIL RIG – Oxidize it loses, reduced it gains

  7. Photosynthesis – process of fixing carbon from the atmosphere into organic material that now has energy from the sun trapped in the bonds of the molecule • What is the chemical formula for photosynthesis? • Review this Prezi: http://prezi.com/2byn9gmriian/photosynthesis/?utm_campaign=share&utm_medium=copy

  8. Cellular Respiration • Review this Prezi: http://prezi.com/8_qehzkw-vuk/cellular-respiration/?utm_campaign=share&utm_medium=copy

  9. Is glucose the only molecule that can be broken down and oxidized during cellular respiration to gain energy?

  10. Measuring primary productivity • Capture plankton • Plankton nets • Ocean color • Chlorophyll colors seawater • SeaWiFs on satellite

  11. Factors affecting primary productivity • Nutrients • Nitrate, phosphorous, iron, silica • Needed for bacteria and phytoplankton to make more DNA, proteins, etc to make more of themselves • Most from river runoff • Productivity high along continental margins because of nutrient runoff • Solar radiation • Uppermost surface seawater and shallow seafloor are most productive, need light! • Euphotic zone surface to about 100 m (330 ft)

  12. Upwelling and nutrient supply • Cooler, deeper seawater nutrient-rich • Areas of coastal upwelling sites of high productivity Fig. 13.6a http://cordellbank.noaa.gov/images/environment/upwelling_470.jpg

  13. Light transmission • Visible light of the electromagnetic spectrum • Blue wavelengths penetrate deepest • Longer wavelengths (red, orange) absorbed first

  14. Light transmission in ocean • Color of ocean ranges from deep blue to yellow-green • Factors • Water depth • Turbidity from runoff • Photosynthetic pigment (chlorophyll) • “dirty” water in coastal areas, lagoons, etc. are areas of high productivity, lots of plankton (preventing that “blue” color) http://upload.wikimedia.org/wikipedia/commons/a/a5/LightningVolt_Deep_Blue_Sea.jpg

  15. Types of photosynthetic marine organisms • Angiosperms • Seed-bearing flowering plants, example is mangroves • Macroscopic (large) algae • Larger seaweeds, like kelp • Microscopic (small) algae • phytoplankton • Photosynthetic bacteria

  16. Macroscopic algae – “Seaweeds” • Brown algae http://www.starfish.ch/photos/plants-Pflanzen/Sargassum.jpg

  17. Macroscopic algae – “Seaweeds” • Green algae Caulerpa brachypus, an invasive species in the Indian River Lagoon Codium http://www.sms.si.edu/IRLspec/images/cbrachypus2.jpg http://192.107.66.195/Buoy/System_Description_Codium_Fragile.jpg

  18. Macroscopic algae – “Seaweeds” • Red algae • Most abundant and most widespread of “seaweeds” • Varied colors http://www.agen.ufl.edu/~chyn/age2062/lect/lect_15/22_14B.GIF http://www.dnrec.state.de.us/MacroAlgae/information/Indentifying.shtml

  19. Microscopic algae http://biologi.uio.no/akv/forskning/mbot/images • Produce food for 99% of marine animals • Most are planktonic - phytoplankton • Golden algae • Diatoms(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

  20. Microscopic algae • Coccolithophores(plates of ate) • Flagellated • calcium carbon plates  possibly sunshades • Coccolithid ooze  fossilized in white cliffs of Dover http://www.esa.int/images

  21. Microscopic algae • Dinoflagellates • Mostly autotrophic; some heterotrophic or both • Flagella in grooves for locomotion • Many bioluminescent • Often toxic when toxin is concentrated due to bloom • Red tides (algal blooms)  fish kills (increase nutrients, runoff) http://oceanworld.tamu.edu/students/fisheries/images/red_tide_bloom_1.jpg http://www.hku.hk/ecology/porcupine/por24gif/Karenia-digitata.jpg

  22. Microscopic algae • Dinoflagellates • Pfiesteriafound in temperate coastal waters • Ciguatera - illness caused from eating fish coated with Gambierdiscustoxicus • Paralytic, diarhetic, amnesic shellfish poisoning Pfiesteria http://www.odu.edu/sci/biology/pfiesteria

  23. Photosynthetic bacteria • Cyanobacteria – many different species • Extremely small • May be responsible for half of total photosynthetic biomass in oceans Anabaena Gleocapsa http://www.micrographia.com/specbiol/bacteri/bacter/bact0200/anabae03.jpg http://silicasecchidisk.conncoll.edu/Pics/Other%20Algae/Blue_Green%20jpegs/Gloeocapsa_Key45.jpg

  24. Regional primary productivity • Varies from very low to very high depending on • Distribution of nutrients • Seasonal changes in solar radiation • About 90% of surface biomass decomposed in surface ocean • About 10% sinks to deeper ocean • Only 1% organic matter not decomposed in deep ocean  reaches bottom • Biological pump (CO2 and nutrients to sea floor sediments)

  25. 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

  26. 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

  27. Tropical ocean productivity • Permanent thermocline is barrier to vertical mixing • Low rate of primary productivity (lack of nutrients) above thermocline • That’s why tropical waters tend to be clear and blue

  28. 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). Examples of these areas are: • Equatorial upwelling • Coastal upwelling (river runoff, etc.) • Coral reefs

  29. Energy flow in marine ecosystems • Consumers eat other organisms • Herbivores (primary consumers) • Carnivores • Omnivores • Bacteriovores • Decomposers breaking down dead organisms or waste products

  30. Nutrient flow in marine ecosystems • Nutrients cycled from one chemical form to another • Biogeochemical cycling • Example, nutrients fixed by producers • Passed onto consumers • Some nutrients released to seawater through decomposers • Nutrients can be recycled through upwelling

  31. Feeding strategies • Suspension feeding or filter feeding • Take in seawater and filter out usable organic matter • Deposit feeding • Take in detritus and sediment and extract usable organic matter • Carnivorous feeding • Organisms capture and eat other animals

  32. Trophic levels • Feeding stage is trophic 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

  33. Food chain Food web • Branching network of many consumers • Consumers more likely to survive with alternative food sources • Primary producer • Herbivore • One or more carnivores

  34. Foodwebs are more complex & more realistic • Consumers often operate at two or more levels http://users.aber.ac.uk/pmm1

  35. Marine fisheries • 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

  36. 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

  37. Aquaculture becoming a more significant component of world fisheries

  38. Incidental catch or bycatch • Bycatch - Non-commercial species (or juveniles of commercial species) taken incidentally by commercial fishers • Bycatch may be 25% or 800% of commercial fish • Birds, turtles, dolphins, sharks http://www.motherjones.com/news/featurex/2006/03/bycatch_265x181.jpg

  39. Incidental catch or bycatch • Technology to help reduce bycatch • Dolphin-safe tuna • TEDs – turtle exclusion devices • Driftnets or gill nets banned in 1989 • Gill nets banned in Florida by constitutional amendment in 1994 http://www.st.nmfs.noaa.gov/st4/images/TurtTEDBlu_small.jpg

  40. http://www.cefas.co.uk/media/70062/fig10b.gif Fisheries management Plaice • Regulate fishing • Closings – Cod fisheries of New England • Seasons • Size 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/70037/fig7b.gif

  41. Fisheries management • Conflicting interests • Conservation vs. economic – “tragedy of the commons” • Self-sustaining marine ecosystems • Human employment • International waters • Enforcement 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.jpg

  42. Fisheries management • Consumer choices in seafood • Consume and purchase seafood from healthy, thriving fisheries • Examples, farmed seafood, Alaska salmon • Avoid overfished or depleted seafood • Examples, bluefin tuna, shark, shrimp, swordfish • Visit: ORCA's Blue Diet page http://marineresearch.ca/hawaii/wp-content/uploads/tuna-auction-largeview.jpg

  43. Figure 13.28

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