AP®︎ Environmental Science: Topic 8.2 Flashcards

The span of environmental conditions an organism can survive; performance is highest in the optimum range, declines in zones of physiological stress, and reaches death beyond the limits of tolerance

A species whose presence, absence, or abundance provides evidence about environmental conditions, often because it is sensitive to pollution

Oxygen gas dissolved in water and available for aerobic respiration, commonly measured in mg/L.

The amount of dissolved oxygen aerobic microorganisms require to decompose organic matter; high BOD generally causes DO to fall

Measure initial DO, seal the sample in darkness for five days at 20°C, measure final DO, and calculate BOD₅ = initial DO − final DO for an undiluted sample

A graph of DO versus distance downstream from an organic-waste or nutrient source: DO falls as decomposition raises BOD, reaches a minimum downstream, and may recover through reaeration, mixing, and photosynthesis

An area of very low dissolved oxygen caused when nutrient-driven biomass dies and decomposition raises BOD, suffocating or displacing aquatic organisms

The loss or expulsion of a coral's symbiotic algae under stress, especially elevated temperature, exposing the white skeleton and depriving the coral of a major energy source

A petroleum release that can poison organisms with hydrocarbons, coat birds and mammals, contaminate benthic habitats and shorelines, and harm fisheries and tourism

Persistent pollution by metallic elements such as lead, mercury, and cadmium, often released by mining, industry, waste, or fossil-fuel combustion and capable of contaminating groundwater and drinking water

Concentration is pollutant amount per unit volume, while load is the total amount transported over time; load = concentration × water flow

A highly toxic, readily absorbed organic form of mercury produced when aquatic bacteria convert elemental or inorganic mercury, allowing it to enter food chains

Discarded material in water that can cause ingestion, choking, intestinal blockage, entanglement, habitat damage, and the movement of toxic substances into food chains

Water cloudiness caused by suspended particles that reduces light penetration and can impair photosynthesis and visual feeding

Excess particles delivered to water by erosion; suspended sediment raises turbidity and reduces light, while deposited sediment buries, fills, or smothers bottom habitats

A condition in which dissolved oxygen is too low to support many aquatic animals; 2 mg/L DO is a common benchmark

The complete absence of dissolved oxygen in water