Lecture 5: Microbes

• Reynolds number is the ratio of inertial to viscous forcs
• Laminar flow has a low Re and is ordered flow with parallel streamlines
• Turbulent flow has a high Re and is irregular flow with crossing layers
• Low Re contains a thick boundary layer

  High Re contains a thin boundary layer
• Pressure varies inversely with fluid velocity
• Pressure drag derives from an upstream/downstream pressure differential (flow separation)
• Skin friction drag derives from shear near surface (no-slip condition/viscosity)
• The three domains of life are bacteria, archaea, and eukarya
• 6 kingdoms of life are fungi, plants, animals, bacteria, archaea, protists
• Marine bacteria are simple prokaryotic organisms, they reproduce asexually through binary fission, and move via flagellum
• Cyanobacteria are photosynthetic bacteria that produce oxygen
• Green and purple sulfur and non-sulfur bacteria are anaerobic and do not produce oxygen
• Sulfur bacteria are referred to as obligate anaerobes
• Nonsulfur bacteria are referred to as facultative anaerobes
• Chemosynthetic bacteria use inorganic chemicals rather than light as a source of energy
• Heterotrophic bacteria are decomposers that use organic matter to obtain energy and material for syntheis
• Some chemosynthetic bacteria live within the tissues of marine tube worms and clams
• Bioluminescence is produced by photocytes (single cells) and photophores (complex glands)

  May arise through either tissue biochemistry (luciferin-luciferase) or symbiotic bacteria
• The luciferin-luciferase system is the oxidative breakdown of luciferin by a specific enzyme called luciferase
• Archaeons are small, single-celled prokaryotes that include photosynthetic, chemosynthetic, and heterotrophic organisms
• Archaea can tolerate extreme environments.

  Hyperthermophiles: can tolerate very warm temperatures

  Halophiles: can tolerate very salty environments