marine microbes

• Viruses are not living organisms because (1) they need host to reproduce and (2) they can't replicate on their own
• 3 theories on virus origin:

  1. degenerated bacteria
  2. came before bacteria
  3. belong to a different tree of life (EX. pandoravirus)
• Virus structure has a (1) nucleocapsid head and (2) body with constituents
• Virus nucleocapsid head is surrounded by a protein coat called capsid and contains DNA
• 3 forms of viruses based on shapes:

  1. Icosahedral
  2. Helical
  3. Binal
• A virus is called a virion when it hasn't infected anything yet/ is still outside its host
• When a virus enters a host it can undergo 2 life cycles:

  1. Lytic
  2. Lysogenic
• Lytic lifecycle is more destructive because it ruptures the cell membrane and leads to cell death
• Lysogenic life cycle is less aggressive because it only incorporates viral DNA to host's circular DNA
• Viruses are the most common in the marine environment, but they are not the most common living organism because they are not living
• Virus count: There is 1010 per liter of surface seawater and 1013 per kg of sediment
• Planktonic viruses are:

  • Icosahedral/ binal
  • Lytic
  • Microscopic and are pelagic (in the water column)
• Sediment viruses are:

  • Helical
  • Lysogenic
• Other specialized viruses include: cyanophages, phycophages, and bacteriophages
• Cyanophages infect blue-green algae
• Phycophages infect algae in general
• Bacteriophages infect bacteria in general
• Viruses control bacterial populations through diseases
• Problems related to virus-caused disease include:

  • Novel diseases are proliferating, strengthening, and spreading
  • Crossing species barrier
  • Economical and ecological effects
• Canine Distemper Virus

  • Common in dogs
  • Caused by dogs defecating in beaches and their feces being swept away by the water
• Morbillivirus

  • Infects cetaceans (whales, dolphins)
  • Causes beaching/ stranding (among other causes like sonar confusion, parasites)
• Fibropapilloma virus

  • causes grooves in turtles' face
• Panaeus monodon with White Spot Syndrome Virus (WSSV)

  • Economically important because it affects aquaculture
  • infected shrimps can no longer be sold
• Pandoravirus (alien virus)

  • Discovered in 2013
  • 93% of genetic material is unlike any other microbe
• Most marine bacteria are BACILLI, there some are cocci
• 2 largest marine bacteria:

  1. Epulopiscium fishelsoni (bacillus)
  2. Thiomargarita namimbiensis (coccus)
• Thiomargarita namibiensis (coccus)

  • Found in Nambimbia
  • Doesn't use sulfur but metabolizes it
• Epulopiscium fishelsoni (bacillus)

  • Infects fish (gut of brown sturgeon)
• Different ways how bacteria gathers nutrients:

  1. Photoautotrophy
  2. Chemoautotrophy
  3. Heterotrophy
• Examples of photoautotrophic bacteria:

  1. prochlorococcus - most common living organism in marine environment
  2. stromatolite - rock deposite with muscilage to help it stick
  3. purple sulfur bacteria - obligately anaerobic; uses H2S and a pigment called bacteriochlorophyll
• Chemosynthetic bacteria are found in deep ocean and extreme environments (EX. gut of deep sea tube worms and deep see hydrothermal vents)
• Heterotrophic bacteria are decomposers, and interact with particles in 3 ways:

  1. Consolidation
  2. Lithification
  3. Sedimentation
• Consolidation: adherence of particles to each other due to mucilage and change in particle’s electrical charges allows them to come together
• Lithification: type of formation of sediments; cementing of minerals between particles because of pH changes (due to bacterial metabolic activity)
• Sedimentation: Disaggregation of particle which settle to the seafloor (may also be due to bacterial metabolic activity)
• Bacteria are bioluminescence suppliers which are an oxygen-dependent process needed by cephalopods like angler fish
• Disease caused by marine bacteria:

  • Banding/ striping in coral reefs
  • Cetaceans infected by streptococcus and staphylococcus
• Archaea is different from bacteria because:

  • their cell walls lack glycoprotein
  • their cell membrane is different in that they are more stable in extreme environments
• Examples of archaea:

  • Methanocaldococcus which produces methane
  • Pyrolobus fumarii in Black Smokers
  • Halobacteria which uses bacteriorhodopsin (only found in archaea)
• Fungi are not very common in marine environment, especially in open oceans