Micro-organisms in the Environment

Autotrophic bacteria (cyanobacteria), phytoplankton, and algae are capable of producing their own food through photosynthesis.
- Photosynthesis allows these organisms to convert light energy into chemical energy in the form of carbohydrates.
The carbohydrates produced serve as a source of energy and nutrients for consumers within ecosystems.
These organisms constitute the crucial first link in a food chain, supporting subsequent trophic levels.
Oxygen, a byproduct of photosynthesis, is released into the environment, becoming available for respiration by other organisms.

Bacteria and fungi function as the primary decomposers in ecosystems.
They break down dead plant and animal remains, facilitating the recycling of nutrients back into the soil.
Saprophytes obtain nutrients by feeding on dead organic matter, contributing to decomposition.

Bacteria play a vital role in the nitrogen cycle, a crucial biogeochemical cycle.
Nitrogen-fixing bacteria convert atmospheric nitrogen into nitrates, a form usable by plants.
Higher plants can only utilize nitrogen in the form of nitrates to synthesize plant proteins.
Plants rely on nitrogen-fixing bacteria to facilitate the conversion of atmospheric nitrogen into a usable form.
Legumes form symbiotic relationships with nitrogen-fixing bacteria in their root nodules.
When plants and animals die, denitrifying bacteria convert nitrates back into atmospheric nitrogen through denitrification.
- This process returns nitrogen to the atmosphere, completing the cycle.