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Biological Productivity

Biological Productivity. 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.

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Biological Productivity

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  1. Biological Productivity

  2. 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.

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

  4. Divisions of the Marine EnvironmentFigure 9-1

  5. 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)

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

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

  8. 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??

  9. 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.

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

  11. 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

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

  13. Diffusion:molecules move from high to low concentrations

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

  15. Phosphate and Nitrate in the Pacific

  16. Silicate in the Pacific

  17. Biolimiting Nutrients • N, P, and Si are exhausted first in 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??

  18. 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

  19. Dissolved O2 Reverse of Nutrients

  20. 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?

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

  22. 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

  23. CZCS Global Primary Production

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