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The Ocean as a Microbial Habitat Matthew Church Marine Microplankton Ecology

The Ocean as a Microbial Habitat Matthew Church Marine Microplankton Ecology. OCN 626/Fall 2008. The Ocean as a Habitat. Energy, nutrients, and life Description of the physical, chemical, and biological environment. What does life require? Energy

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The Ocean as a Microbial Habitat Matthew Church Marine Microplankton Ecology

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  1. The Ocean as a Microbial HabitatMatthew ChurchMarine Microplankton Ecology OCN 626/Fall 2008

  2. The Ocean as a Habitat • Energy, nutrients, and life • Description of the physical, chemical, and biological environment

  3. What does life require? • Energy • Nutrients (carbon, nitrogen, phosphorus, oxygen, sulfur, etc., etc.) • Electron donor-a source of reductant • Electron acceptor- required for respiration • Common habitat controls microorganism distributions and abundance • Light • Nutrients • Temperature • Pressure • Redox environment

  4. Energy flows, matter cycles

  5. Sources of energy for life in the sea H2S Glucose Light-aside from hydrothermal vents, sunlight is the ultimate energy source for life in the sea (phototrophy). Chemical-both organic and inorganic compounds (chemotrophy).

  6. Nutrient sources • Nitrogen: protein, nucleic acids • NO3-, NO2-, N2, NH3, organic N • Phosphorus: nucleic acids, lipids • PO43-, organic P • Carbon: nucleic acids, protein, lipids, carbohydrates, etc. • CO2, organic C • Sulfur: amino acids, protein, lipids • SO42-, S, H2S, organic S

  7. Spatial gradients in the marine environment • Light, Salinity, Nutrients, Temperature, Pressure

  8. Time-space scales of physical processes F Z P B Scales of variability are important Note that increasing time scales generally correspond to increasing space scales • Generation time of a tree: • years • Generation time of microbe: • minutes to days From T. Dickey

  9. Temperature-salinity plot from Station ALOHA showing the time-dependent changes in physical ocean properties. Note greater variability in physical environment in upper 200 m; deep sea (>1000 m) largely invariant with time.

  10. ~30X variation in temperature in the surface ocean ~4X variation in temperature in the deep sea NOAA-NESDIS-National Oceanographic Data Center

  11. The ocean is stirred more than mixed Sea Surface Temperature Chl a (°C) (mg m-3)

  12. Spatial discontinuities at various scales (basin, mesoscale, microscale) in the ocean habitat play an important role in controlling the growth of microorganisms. Yoder, 1994

  13. Shelford’s Law of Tolerances: The distribution and abundance of an organism will be controlled by that environmental factor for which the species has the narrowest range of tolerance.

  14. Organisms have evolved specific tolerances to habitat variables (light, temperature, nutrients, pH, oxygen, salinity) Most organisms in the oceans are psychrophiles and mesophiles Oceans Oceans

  15. Temperature plays an important role in controlling plankton growth and distributions. In this example, diatoms have a wider range of optimal temperatures than flagellated phytoplankton. Divisions per day Temperature (oC) Which group of plankton would be predicted to have a more cosmopolitan distribution?

  16. Light transmission through the atmosphere and ocean Energy impinging on the Earth’s surface is most intense in visible portion of the spectrum UV Visible Infrared

  17. Profile of irradiance with depth In the blue-green regions of the visible spectrum, sunlight penetrates deep into the ocean Data from Station ALOHA

  18. Differences in growth as a function of light energy by 4 isolates of Prochlorococcus

  19. Vertical Profiles of Nutrients Nutrient distributions with depth (pressure) at Station ALOHA

  20. NOAA-NESDIS-National Oceanographic Data Center Nutrient availability is governed by physics: mixing, upwelling, advection, diffusion AND biology: the balance between assimilation and remineralization

  21. 7 years of ocean chlorophyll from satellites Mean Maximum Minimum High latitudes are highly variable, central gyres more stable

  22. Biological variability in space and time Spatially coherent interannual variability in selected ecosystems (equator for example) but most ocean ecosystems appear highly variable in space and time

  23. The mesopelagic zone is an important region of decomposition. Photosynthetically derived material produced in the well-lit upper ocean sinks to the ocean’s interior-microbes in the mesopelagic rely on this sinking material for energy.

  24. Basin scale differences in nutrient concentrations controlled by biology (decomposition) and physics (thermohaline circulation)

  25. The bathypelagic

  26. Barophilic (or piezophilic) microorganisms • Barophilic microorganisms grow optimally at pressures in excess of 1 atm. • Low temperatures and high pressures both solidify lipids (cell membranes). • Microorganisms can adapt to changes in pressure by increasing or decreasing the fluidity of cell membranes through changes in fatty acid composition (through production of unsaturated fatty acids)

  27. Yayanos et al. (1981) PNAS

  28. Interactive influences of pressure and temperature on the growth of a bacterium isolated from Mariana Trench

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