Biological Roles of Microbes: Positive and Negative Impacts

Positive Roles of Microbes

• Chemical Cycles:

  • Microbes participate actively in essential global nutrient cycles, including the oxygen cycle, carbon cycle, and nitrogen cycle.

  • Carbon and Oxygen Cycle Dynamics:

  • Fish expel carbon dioxide ($CO_2$) into the aquatic environment.

  • Plants absorb the expelled carbon dioxide ($CO_2$) and release oxygen ($O_2$).

  • Nitrogen Cycle Dynamics:

  • Fish expel nitrogenous waste in the form of ammonia ($NH_2$).

  • Nitrosomanus bacteria take in ammonia ($NH_2$) and convert it into nitrites.

  • The resulting nitrites are then absorbed and processed by another bacteria.

• Bioremediation:

  • Microbes are deployed for environmental cleanup.

  • Bacteria are sprayed on oil spills to break down complex hydrocarbons into non-toxic substances.

• Production of Food and Consumables:

  • Microbial fermentation and metabolic processes are essential in the manufacturing of key food and beverage items, including:

  • Yogurt

  • Wine

  • Cheese

  • Bread

• Biotechnology and Gene Therapy:

  • Scientists genetically manipulate bacteria through molecular techniques to produce valuable biomedical and agricultural products.

  • Applications include the synthesized production of:

  • Antibiotics

  • Pesticides

• Normal Flora:

  • Normal flora consists of beneficial microbes inhabiting the interior and exterior of the body.

  • Primary biological functions include:

  • Aiding in the digestion of nutrients.

  • Supporting proper immune system function and defense.

• Symbiosis:

  • Microbes establish specialized symbiotic relationships with diverse biological organisms. Notable examples include:

  • Soybeans

  • Algae/Coral

  • Termites/Protozoans

Negative Roles of Microbes

• Indirect Effects:

  • Crop Destruction:

  • Plant pathogens destroy agricultural crops, threatening global food production.

  • Algae Blooms:

  • Excessive proliferation of algae pulls oxygen out of aquatic environments during nighttime hours.

  • The severe reduction in available dissolved oxygen drowns and suffocates fish populations.

  • Food Spoilage:

  • Fungal growth, such as mold, causes food degradation and spoilage.

• Direct Effects:

  • Infectious Disease:

  • Pathogenic microbes and toxic microbial products (toxins) directly cause infectious diseases in host populations.

  • Emerging Infectious Diseases:

  • Diseases that are either entirely new to a population or previously existed at minor baseline levels and are now actively surging in incidence.

  • Re-emerging / Resurgent Infectious Diseases:

  • Pathogenic infections that historically existed, decreased significantly in population prevalence, and have recently resurged.