Nutrient Cycles and Ecosystem Productivity: Carbon, Nitrogen, Phosphorus

Movement of energy and matter in the biosphere

Energy flows in one direction, while matter is recycled within and between ecosystems.

Biogeochemical cycles

Processes that pass matter from one organism to another and between different parts of the biosphere.

Water cycle

The movement of water between the ocean, atmosphere, and land.

Importance of nutrients

Essential substances required for building tissues and carrying out life functions in living organisms.

Carbon cycle

The movement of carbon through biological processes like photosynthesis and respiration, as well as geochemical processes like erosion.

Human contributions to the carbon cycle

Activities such as mining, cutting and burning forests, and burning fossil fuels that release carbon dioxide into the atmosphere.

Nitrogen fixation

The process by which certain bacteria convert nitrogen gas into ammonia.

Producer utilization of nitrogen

Producers use nitrates and nitrites, converted from ammonia by bacteria, to synthesize proteins.

Fate of nitrogen after organism death

Decomposers return nitrogen to the soil as ammonia, which can subsequently be reused by producers.

Denitrification

The process by which soil bacteria convert nitrates back into nitrogen gas, releasing it into the atmosphere.

Biological importance of phosphorus

Essential component required for forming key biological molecules such as DNA and RNA.

Limiting nutrient

A substance that is scarce or cycles very slowly, restricting an organism's or population's growth.

Algal bloom

An immediate, rapid increase in algae and other producers caused by a large input of a limiting nutrient.

Consequences of an algal bloom

Disruption of ecosystem equilibrium by covering the water surface, blocking sunlight, and leading to severe oxygen depletion.

Decomposition during an algal bloom

Decomposing organic matter causes exponential growth of bacteria, consuming most of the oxygen and killing other consumers.

Effect of nutrient availability on primary productivity

The amount of available nutrients controls the rate at which organic matter is created by producers in an ecosystem.

Impact of nutrient limitation on ecosystem health

When an ecosystem is limited by a single nutrient, overall growth is restricted and ecological balance can be disrupted.