Nitrogen & Phosphorus cycles, and Bioaccumulation of Toxins in the food chain

Nitrogen

An essential element needed for making amino acids and nucleic acids (DNA & RNA); important for proteins that make up muscle and enzymes.

Phosphorus

An essential element needed for DNA, RNA, ATP (energy currency of the cell), and phospholipids (cell membranes).

Nitrogen Fixation

The process of converting atmospheric nitrogen (N2) into a usable form for organisms, done by nitrogen-fixing bacteria or through lightning.

Nitrification

The process in which ammonia (NH3/NH4+) is converted to nitrite (NO2-) and then to nitrate (NO3-) by nitrifying bacteria.

Assimilation

The process by which plants absorb nitrogen through roots and animals obtain nitrogen by consuming plants or other animals.

Ammonification

The process where decomposers break down dead matter and waste, releasing nitrogen back into the form of ammonium (NH4+).

Denitrification

The process of converting nitrate (NO3-) back into nitrogen gas (N2), which returns to the atmosphere.

Eutrophication

A process triggered by excess phosphates in water, leading to algal blooms, reduced oxygen levels, and dead zones.

Bioaccumulation

The buildup of a toxic substance in the tissues of a single organism over its lifetime, particularly fat-soluble toxins.

Biomagnification

The increase in concentration of a toxin as it moves up the food chain, resulting in higher levels in predators.

Classic Example of Biomagnification

DDT is sprayed to kill insects, absorbed by plants, eaten by small fish, then larger fish, leading to high concentrations in eagles, causing thin eggshells and population crashes.