Topic 4 Definitions

Ocean Conveyor Belt

Large scale circulation of the ocean’s waters that is largely responsible for the transfer of heat from the tropics to the colder regions

Economic Water Scarcity

Where a country physically has sufficient water to meet its needs, but requires additional storage and transport facilities.

Physical Water Scarcity

Where water consumption exceeds 60% of the usable supply.

Grey Water

Waste water that has been produced in homes and offices but doesn’t not contain faecal material.

Water Insecurity

A lack of access to sufficient amounts of safe drinking water.

Aquaculture

Raising fish commercially as food for humans and/or animal feed.

Maximum Sustainable Yield

The rate of increase in natural capital that can be exploited without depleting the original stock or its potential from replenishment.

Biochemical Oxygen Demand (BOD)

A measure of the amount of dissolved oxygen required to break down the organic material in a given volume of water through aerobic biological activity.

Eutrophication

The natural/artificial enrichment of a body of water, particularly with nitrates and phosphates, that results in depletion of oxygen levels in the water.

Biotic Index

The use of plant/animal species to make conclusions about the level of pollution.