Cyanobacteria Pre-Lab Notes

Cyanobacteria: An Overview

What are Cyanobacteria?

  • Also known as blue-green algae.
  • Photosynthetic bacteria that convert sunlight into energy through photosynthesis.
  • Prokaryotic organisms.
  • Found in various aquatic environments:
    • Freshwater
    • Marine
    • Brackish water (where fresh and marine water meet).
  • Can thrive in moist areas.

Importance of Cyanobacteria

  • Play a crucial role in ecosystems by producing oxygen.
  • Form the base of aquatic food webs, enabling energy transfer between trophic levels.

Harmful Algal Blooms

  • Excessive cyanobacteria growth can lead to harmful algal blooms.
  • Triggered by increased phosphate levels in the environment.
  • Can produce toxins harmful to aquatic life and humans.

Classification

  • Prokaryotic, belonging to the domain Bacteria and Archaea.
  • Simple cell structure with genetic material organized in a single circular chromosome in the cytoplasm.

Symbiotic Relationships

  • Can be symbionts with other marine organisms.
  • Example: Elysia species (sea slug) that consumes cyanobacteria.
    • The sea slug incorporates chloroplasts from the cyanobacteria into its body.
    • Cyanobacteria provide food to the sea slug, a mutualistic relationship.
    • The sea slug isn't photosynthetic on its own but uses the cyanobacteria's chloroplasts.

Body Organization

  • Various forms of body organization:
    • Cocoid (Unicellular): Solitary cells.
      • Example: Croupoccus
    • Colonial: Two or more cells in a jelly-like mass or gelatinous sheet.
      • Cells can be arranged randomly or in a pattern.
    • Filamentous: Multicellular, forming trichomes (series of cells in a line).
      • Examples: Oscillatoria and Anabaena
Filamentous Types
  • Uniseriate: Cells arranged in a single row, forming a single chain or filament.
    • Examples: Oscillatoria and Anabaena
  • Multiseriate: Cells arranged in multiple rows, side by side, forming a broader or thicker filament.
    • Examples: Tolypothrix and Hydrodictyon
Heterocysts
  • Specialized cells in filaments that fix nitrogen.
  • Filamentous organisms with heterocysts are called homocystis.
Branching
  • Filamentous cyanobacteria can be branching or non-branching.
  • False branching: Cells appear to attach but are not a product of cell division.
    *Note: the transcript makes it sound like Homocystis is having heterocysts, but it means