marine microbiology

• What is the focus of marine microbiology?

  Microbiology of the marine environment
• What are the main groups of microbes in the photic zone?

  • Micro: cyanobacteria, proteobacteria, dinoflagellates, diatoms
  • Nano: algae, flagellated protists
  • Pico: bacteria and small eukaryotes
  • Femto: viruses
• What are diatoms known for in marine environments?

  They are the largest group of algal protists
• What is the composition of diatoms' structure?

  Silicon dioxide with holes for gas exchange
• How do marine diatoms contribute to the sea floor?

  They contribute to biogenic ooze upon death
• What are dinoflagellates commonly referred to as?

  The fire plants of the ocean
• How many species of dinoflagellates are approximately known?

  About 3,400 species
• What is a unique feature of many dinoflagellates?

  Many are bioluminescent species
• What role do viruses play in marine ecosystems?

  They are essential to nutrient cycles
• How do viruses affect microbial plankton populations?

  They undergo predation on all levels
• What nutrients do viruses help return to marine systems?

  Nitrogen and carbon
• What is the microbial marine food web dependent on?

  Primary production from phytoplankton and viruses
• What defines the aphotic zone in marine environments?

  Less than 1% of sunlight penetrates
• What is the impact of cell lysis by viruses on planktonic biomass?

  It breaks down approximately half of it
• What are the depth divisions of the aphotic zone?

  Bathyal, abyssal, and hadal zones
• What do all life forms in the aphotic zone rely on?

  Particulate organic matter and dissolved organic matter
• What are the key characteristics of microbial metabolism in marine environments?

  1. Carbon acquisition:

  • Autotrophic: from inorganic compounds (e.g., CO₂)
  • Heterotrophic: from organic compounds (e.g., sugars)

  1. Energy derivation:

  • Chemotrophic: from external chemical compounds
  • Phototrophic: from light

  1. Reducing equivalents generation:

  • Lithotrophic: from inorganic compounds
  • Organotrophic: from organic compounds
• What is the benthic zone?

  Where the water column meets the ocean floor
• What types of organisms are found in the benthic zone?

  Barophilic, thermophilic, and psychrophilic organisms
• What is the pressure tolerance of most benthic organisms?

  Up to 1100 atm
• What is the primary metabolism type of most benthic organisms?

  Chemolithotrophic metabolism
• What do hydrothermal vents provide for benthic organisms?

  Reduced inorganic power for growth
• What is the role of Riftia pachyptila in hydrothermal vent ecosystems?

  It relies on endosymbiotic H₂S reducing bacteria
• What are cold seeps?

  Regions where methane or petroleum leak through the ocean floor
• What do psychrophilic methanogens do at cold seeps?

  Convert acetate to methane for nutrition
• What are the learning outcomes of the marine microbiology lecture?

  • Knowledge of microbiology in marine environments
  • Importance of viruses in nutrient cycles
  • Importance of endosymbiosis in the deep ocean
• How is the marine environment categorized?

  By distance from the coast, depth, and light availability
• What are the ecological zones of the marine environment?

  • Neuston
  • Euphotic (photic) zone
  • Aphotic zone
  • Benthos (sea floor)
• What is the significance of the photic zones?

  They contain the highest concentration of microorganisms
• What is the depth range of the euphotic zone?

  100 to approximately 300 meters
• What is the primary production site in the marine environment?

  The euphotic zone due to sunlight availability
• What types of microbes are found in the photic zone?

  • Free-floating marine photosynthetic bacteria
  • Non-photosynthetic bacteria
  • Eukaryotes (protists)
  • Viruses