Human Influences on Ecosystems - Pollution

Eutrophication: The process where excess nutrients, specifically nitrates ($NO_3^-$) and phosphates ($PO_4^{3-}$), leach into water bodies, leading to rapid algal growth, oxygen ($O_2$) depletion, and the death of aquatic organisms.

Greenhouse Effect: The trapping of infrared radiation by gases such as carbon dioxide ($CO_2$), methane ($CH_4$), nitrous oxide ($N_2O$), and $CFCs$, leading to an increase in the Earth's mean temperature.

Acid Rain: Formed when sulfur dioxide ($SO_2$) and oxides of nitrogen ($NO_x$) dissolve in rainwater to form sulfuric acid ($H_2SO_4$) and nitric acid ($HNO_3$), lowering the $pH$ of ecosystems.

Bioaccumulation: The buildup of persistent, non-biodegradable chemicals (e.g., heavy metals like $Hg^{2+}$ or pesticides like $DDT$) within the tissues of a single organism over time.

Biomagnification: The increase in concentration of a pollutant as it passes along a food chain to higher trophic levels, often reaching toxic levels in top predators.

Sewage Pollution: Untreated sewage provides a food source for aerobic bacteria, which multiply and consume dissolved oxygen ($O_2$) through respiration, leading to a high Biological Oxygen Demand ($BOD$).