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.