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Biological Productivity

Biological Productivity. Conditions for Life in the Sea. Consider the main biochemical reaction for life in the sea, and on earth in general: 6H 2 O + 6CO 2 + energy + nutrients = C 6 H 12 O 6 + 6O 2 Focus on left side of equation

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Biological Productivity

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  1. Biological Productivity

  2. Conditions for Life in the Sea Consider the main biochemical reaction for life in the sea, and on earth in general: 6H2O + 6CO2 + energy + nutrients = C6H12O6 + 6O2 Focus on left side of equation What is in short supply in the sea and thus limits the amount of life in the ocean??

  3. Absorbing Nutrients6H2O + 6CO2 + energy + nutrients = C6H12O6 + 6O2 • Phytoplankton are base of the food chain • Most important primary producers of complex sugars and oxygen Lauderia sp.

  4. Open Ocean Food Webs Coccolithophores ARCOD@ims.uaf.edu Copepods Barrie Kovish Pacific Salmon Vicki Fabry Pteropods

  5. Present Ocean Food Web– Complex ecosystem interactions based on a low CO2 ocean Ocean Food Web Primary Producers Upper Trophic Levels Zooplankton Food Web Sinking Organic Debris Provided by James Barry MBARI Microbial Remineralization Seafloor community

  6. Absorbing Nutrients • Nutrients absorbed by plants through diffusion across a semi-permeable membrane Lauderia sp.

  7. Diffusion:molecules move from high to low concentrations

  8. Which Nutrients are in Short Supply? • Nitrogen (N) as Nitrate NO3(-2) • Phosphorus (P) as Phosphate PO4(-2) • Silicon (Si) as Silicate SiO4(-2)

  9. Phosphate and Nitrate in the Pacific

  10. Silicate in the Pacific

  11. Biolimiting Nutrients • N, P, and Si are exhausted first in Eq. surface waters during photosynthesis • Essential to the growth of phytoplankton • If these biolimiting nutrients increase in sea water, life increases • If these biolimiting nutrients decrease in sea water, life decreases • Where would you expect to find the highest biomass in the Pacific??

  12. CZCS Global Primary Production

  13. How Does Nutrient Distribution Compare w/Dissolved Oxygen? 6H2O + 6CO2 + energy + nutrients = C6H12O6 + 6O2 • O2 is high in the surface and mixed layer • O2 decreases to a minimum at base of thermocline • O2 then steadily increases with depth

  14. Dissolved O2 Reverse of Nutrients

  15. Why is the Concentration of Oxygen High in the Mixed Layer?? Hint #1: How and where is oxygen produced in the sea??? 6H2O + 6CO2 + energy + nutrients = C6H12O6 + 6O2 Hint #2: How can oxygen be mixed downward from the atmosphere into the ocean?

  16. How is Oxygen Removed from the Thermocline & Slightly Below??

  17. Dead and decaying organic matter sinks downward from surface waters • Rate of sinking decreases as it encounters the cold, dense water of the thermocline • Material decays (oxidizes) at the thermocline, which strips O2 out of the water and returns nutrients to the sea • Cold, nutrient-rich water of the thermocline is returned to sunlit surface waters by way of upwelling

  18. CZCS Global Primary Production

  19. Marine Ecology

  20. Basic Ecology • physical and chemical parameters affecting distribution and abundance • An ecosystem includes both the living (biotic) and non-living (abiotic) portions of the environment. • Examples include: salt marshes, estuaries, coral reefs, the North Pacific Gyre.

  21. Classification of Organisms by Environment • horizontal: neritic | oceanic • vertical: • epipelagic (top) / euphotic (good) • mesopelagic (middle) / disphotic (low) • bathypelagic (deep) / aphotic (without) • abyssopelagic (“bottomless”)

  22. Divisions of the Marine EnvironmentFigure 9-1

  23. Classification of Organismsby Lifestyle • Scientists have established another classification scheme to categorize biota on the basis of lifestyle. The major groups are: • plankton (floaters) • nekton (swimmers) • benthos (bottom dwellers)

  24. Plankton • weak swimmers, drifters, unable to counteract currents. • Phytoplankton (plants) • Zooplankton (animals)

  25. Nekton • active swimmers capable of counteracting currents. • Fish • Squids • Reptiles • Birds • Mammals

  26. Distribution of Marine Lifestyles • 16.7% of Earth’s animals are marine • 2% inhabit pelagic environment (most of the oceans are cold and dark) • 98% are benthic!

  27. Benthos • Epiflora or epifauna live on the sea bottom. • Infauna live in the sea bottom. • Benthic plants - restricted to shallow waters (light) • Benthic animals occur everywhere from shallow depths to the deep sea.

  28. Research Video Clips:“Live fast, die young...”

  29. Hydrostatic Pressure • Pressure caused by the height of water. • Function of water height and water density • Pressure generally increases at a rate of 1 atm per 10 m of water. ( or 16 psi per 10 m depth)

  30. Think You’re Under Pressure Now?

  31. Hydrostatic Pressure(Cont.) • enormous in the deep sea yet animals live there. • Animals do not contain gases. • However, mesopelagic fishwhich have gas-filled swim bladders to help maintain neutral buoyancy • unable to move rapidly between depths • pressure change could cause bladder explode.

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