EVS (HYDROSPHERE)

Where is saltwater found & in what amounts?

97% = saltwater (oceans).

Where is freshwater found & in what amounts?

3% = freshwater (glaciers, ice caps, groundwater, rivers, lakes).

Surface run-off

Water flowing over the land into rivers, lakes, or oceans.

Infiltration

Water soaking into the ground and moving into soil/rock.

Precipitation

Water falling from clouds: rain, hail, sleet, snow.

Evaporation

Liquid water turning into water vapour due to heat.

Transpiration

Water vapour released from plants through their leaves.

Water Stress

When water demand is greater than supply in an area.

What is eutrophication?

Excess nutrients (nitrogen + phosphorus) cause rapid algae growth in water.

What causes eutrophication?

Fertilisers, sewage, detergents, animal waste.

What organisms does it affect & how?

Algal bloom, blocks sunlight, plants die, bacteria decompose plants, bacteria use oxygen, fish and aquatic life suffocate.

Examples of pollutants/contaminants in water

heavy metals, plastics, pesticides, fertilisers, oil, sewage, detergents.

What is water quality testing?

Measuring physical, chemical, or biological factors to determine how healthy/safe the water is.

Three examples of water tests

pH, turbidity, temperature, nitrate levels.

What is macroinvertebrate testing?

Checking which small water animals live in the water to judge water quality.

How do macroinvertebrates indicate water quality?

Some species are sensitive to pollution (mayflies, stoneflies).
Some survive in poor quality (worms, midges).
More sensitive species = clean water.