B.Sc. Industrial Microbiology III: Habitat Ecology

Study Notes

An ecosystem consists of biotic (living organisms) and abiotic (physical environment) components, interacting as a system.
Energy flows through the ecosystem via food chains and webs, while nutrients cycle among organisms and the environment.
Key processes include photosynthesis, respiration, decomposition, and nutrient cycling, maintaining ecosystem health and balance.

Soil profile consists of layers (horizons): organic matter (O horizon), topsoil (A horizon), subsoil (B horizon), and bedrock (C horizon).
Soil microflora includes bacteria, fungi, actinomycetes, and algae, which play crucial roles in:
- Nutrient cycling
- Organic matter decomposition
- Soil structure maintenance

Freshwater habitats contain microflora like bacteria, cyanobacteria, algae, and protozoa, essential for:
- Nutrient cycling
- Water purification
Marine habitats host diverse microflora, including phytoplankton, bacteria, and archaea, which contribute to:
- Primary production
- Biogeochemical cycles
- Marine food webs

Aeromicroflora consists of airborne microorganisms like bacteria, fungi, and viruses.
These microbes are dispersed through air currents, weather events, and human activities.
Aeromicroflora impacts:
- Air quality
- Human health
- Atmospheric processes (cloud formation, nutrient cycling)

Human microbiome includes bacteria, fungi, viruses, and archaea residing in and on the human body.
These microbes aid:
- Digestion
- Immune function
- Overall health
In ruminants, microbes in the stomach (rumen) help:
- Break down cellulose
- Ferment plant materials
- Nutrient absorption and energy production

Microbial succession in plant decomposition involves a sequence of microbial communities breaking down organic matter.
The process involves:
- Initial degradation of simple compounds by bacteria and fungi
- Breakdown of cellulose by cellulolytic microbes
- Decomposition of complex molecules by lignin-degrading fungi
- Recycling of nutrients back into the ecosystem

Microbial interactions encompass various relationships among microorganisms and between microorganisms and their environment.
These interactions determine the structure and function of microbial communities.
Types of microbial interactions include:
Mutualism
- Definition: A symbiotic relationship where both organisms benefit.
- Example: Lichens (mutualistic relationship between fungi and photosynthetic algae or cyanobacteria)
Synergism
- Definition: An interaction where two organisms work together to achieve a result that neither could accomplish alone.
- Example: Certain bacteria and fungi working together in soil to degrade complex organic compounds
Commensalism
- Definition: A relationship where one organism benefits, and the other is not affected.
- (Example not provided)