Aquatic Microbiology

Aquatic Microbiology Definition: The study of microorganisms such as bacteria, viruses, algae, fungi, and protozoa in fresh, estuarine, and marine waters. Significance:

  • Affects the well-being of humans and organisms.
  • Important trophic level in food chains, providing nourishment for higher trophic levels.
  • Participates in biochemical reactions and recycling processes.
  • Addresses urbanization and human water consumption demands.
  • Key component of food sources.
  • Aids in offshore exploration of oil and minerals. Sources of Water Water Cycle: Natural water circulates through evaporation and precipitation. Classifications:
  • Atmospheric Water: Moisture in clouds contributing to snow, dew, frost, sleet, hail, drizzle, and rain.
  • Surface Water: Water on the earth's surface, divided into:
    • Stored Water (Lentic): Includes ponds, lakes, reservoirs, and oceans.
      • Ponds: Temporary (seasonal) and permanent.
      • Lakes:
      • Oligotrophic: Nutrient-poor, deep lakes that support limited life.
      • Eutrophic: Nutrient-rich, supporting abundant flora and fauna.
      • Dystrophic: Humus-rich but low oxygen, acidifying water.
    • Running Water (Lotic): Rivers, characterized by currents and high oxygen levels.
  • Ground Water: Subterranean water from percolating rain, existing as hygroscopic, capillary, gravitational, combined water, and vapor. Water Pollution Sources Natural Pollutants: Polluted by running water gathering minerals and particles; anthropogenic activities worsen this. Types of Pollution:
  • Municipal Effluents: Contaminated from domestic activities and sewage, leading to oxygen depletion and increased BOD.
  • Agricultural Pollution: Pesticides and fertilizers run-off contaminating aquatic environments, contributing to biomagnification.
  • Industrial Effluents: Varying pollutants from different industries affecting water quality.
    • E.g., DDT accumulation in humans poses health risks. Sewage Water Treatment:
  • Overview: Sewage treatment is a process to remove contaminants from wastewater, primarily from household and industrial sources, ensuring that the water can be safely returned to the environment or reused.
  • Stages in Sewage Treatment:
    1. Preliminary Treatment:
      • Physical processes such as screening and grit removal to capture large objects (like sticks, plastics, and other debris).
    2. Primary Treatment:
      • Sedimentation allows solids to settle, creating sludge, while lighter wastes, like oils, float to the top and are skimmed off.
    3. Secondary Treatment:
      • Biological processes using microorganisms to digest organic matter, typically in aeration tanks where air is pumped in to promote bacterial growth. Sludge is further treated or recycled.
    4. Tertiary Treatment:
      • Advanced treatment such as filtration and disinfection (using chlorine, UV light, or ozone) to remove remaining solids and pathogens, making it suitable for discharge or reuse.
    5. Sludge Treatment:
      • Stabilization can occur through anaerobic digestion, composting, or incineration to reduce volume and make it safe for application or disposal. Testing Water Quality Physical Parameters: Appearance, color, odor, taste, turbidity, temperature, density. Chemical Parameters: Presence of harmful chemicals (based on recommended limits for drinking water). Biological Parameters: Measures presence of pathogenic organisms (e.g., Escherichia coli as an indicator of pollution). Certification Processes: Standard plate count, membrane filter technique, MPN (Most Probable Number). Microorganisms in Marine Environments Marine Microbiology: Focuses on microbial flora including bacteria, algae, protozoa, fungi. Microorganisms' Distribution:
  • Horizontal: Higher counts in coastal waters ( 100,000/ml) vs. open sea (<10/ml).
  • Vertical: Varies with depth depending on environmental conditions. Types:
  • Plankton:
    • Phytoplankton: Primary producers (e.g., diatoms, cyanobacteria).
    • Zooplankton: Protozoans feeding on phytoplankton (e.g., Foraminifera).
  • Benthic Organisms: Found in sediments; decompose materials. Aquatic Ecosystem Functions Primary Productivity: Phytoplankton's growth depending on energy sources and nutrients. Biogeochemical Cycles: Microorganisms facilitate cycles of nitrogen, carbon, sulfur, phosphorus. Importance of Microbes:
  • Recycle minerals and organic matter in the ecosystem.
  • Facilitate limestone and petroleum formation. Microbiology of Domestic Water Sources & Contaminants: Includes water from various sources polluted by microorganisms (e.g., coliforms, viruses, protozoans). Common Microorganisms:
  • Bacteria: E.g., E. coli, Pseudomonas, Salmonella.
  • Viruses: E.g., poliovirus.
  • Protozoa: E.g., Giardia.
  • Algae & Fungi: Various species affecting water quality. Purification of Potable Water Methods:
  • Sedimentation: Removes suspended particles using large storage tanks with potential chemical aids (alum, activated carbon).
  • Filtration: Removes bacteria through sand filter beds with various configurations.
  • Disinfection: Utilizes methods like chlorination, ozonation, UV light irradiation, and boiling. Conclusion Quality Testing Methods: Evaluate sanitary quality to determine if water is potable, focusing on bacterial counts as pollution indicators. Potable water is essential for human health and well-being and must be effectively purified and tested regularly to ensure safety.