Ch 4 : Water, Food Production Systems and Society

Ocean currents

________: are movements of water both horizontally and vertically.

Discharges

________: by adding pollutants to water.

Condensation

________: water vapour to liquid.

Salinization

________: process of naturally dissolving minerals in the top layer of the soil which makes it too salty (________) for further agriculture.

Evaporation

________: liquid to water.

Surface currents

________: moved by the wind.

Transfers

________: occur when it stays in the same state:

Irrigation

________: results in soil degradation especially in dry areas.

Scarcity of water resources

________ can lead to conflict between human populations especially when resources are shared.

Renewable resources

________: atmosphere, rivers.

Withdrawals

________: domestic use, irrigation in agriculture and industry.

Hydrological cycle

________: system of water flows and storages that may be disputed by human activity.

Cold ocean currents

________ run from poles to the equator, warm water currents flow from the equator to the poles.

→ irrigation

________: select drought resistant crops.

Deep water currents

________ (thermohaline currents): influenced by the oceanic conveyor belt.

Water budget

________: quantitative estimate of the amount of water in storages and flows of the water cycle.

Hydrological cycle

system of water flows and storages that may be disputed by human activity

Water budget

quantitative estimate of the amount of water in storages and flows of the water cycle

Renewable resources

atmosphere, rivers

Non-renewable resources

oceans, icecaps

Middle group

groundwater aquifers

Transfers

occur when it stays in the same state

Transformations

when it changes state to and from water

Evaporation

liquid to water

Condensation

water vapour to liquid

Freezing

solid snow to ice

Withdrawals

domestic use, irrigation in agriculture and industry

Discharges

by adding pollutants to water

Ocean currents

are movements of water both horizontally and vertically

Surface currents

moved by the wind

Deep water currents (thermohaline currents)

influenced by the oceanic conveyor belt

Irrigation

results in soil degradation especially in dry areas

Salinization

process of naturally dissolving minerals in the top layer  of the soil which makes it too salty (saline) for further agriculture

→ irrigation

select drought resistant crops

**Biochemical oxygen demand**

amount of DO required to break down organic material in a given volume of water

**Eutrophication**

when lakes and coastal waters receive inputs of nutrients (nitrates and phosphates) that result in an excess growth of plants and phytoplankton

**Indicator species**

plants and animals that show something about the environment by their presence, absence, abundance

**Biotic index**

indirectly measures pollution by assessing the impact on species within the community according the their tolerance, diversity, and relative abundance

**BOD**

amount of dissolved oxygen required to breakdown organic material in a given volume of water

**Marine pollution**

rivers, human pollution, pipelines

**Freshwater pollution**

agricultural runoff, sewage, solid domestic waste

**Continental shelf**

extension of continents under the seas and oceans (creates shallow water)