4. notes and revision Flashcards
The hydrological cycle aka the water cycle
this is a system of waterflows and storages that may be disrupted by human activity
transfers in the water cycle include
flooding
transformations in the water cycle include
freezing
condensation
evapotranspiration because its both from trees and water bodies
storages in the water cycle include
ocean
lakes
rivers
Human impact on the water cycle
Water pollution
Intense irrigation
DEFFORESTATION
GWEICO
Ocean currents
These are movements of water both vertically and horizontally.
Surface currrents
These are moved by the wind
deep currents
these are moved by the ocean belt
draw the water cycle
water scarcity
This is when there is insufficient water to meet the needs of a population
this is the reduction of water levels
Water degredation
This is the reduction of water quality making it unsustainable for use
Problems faced with fresh water
GWEIC
Global warming
Waterpollution
intense irrigation
Eutrophication
Climate change = less rain
Low water level in water bodies due to evapouration due to increasing global temperatures
Fertilizers polluting streams
Intensive irrigation; water evapourates even before reaching plants
Solutions to fresh water problems
Increase reserviours
Rainwater harvesting
Plant drought resistant crops
reduce pesticide use
Education
Legislation
restoration
continental shelf
The continental shelf is the extension of continents under the seas and oceans.
Phytoplankton
Phytoplankton are single-celled organisms that can photosynthesize
Benthic
Benthic – living on or in the sea bed
Pelagic
Pelagic – living surrounded by water from above the sea bed to the surface.
Aquaculture
aquaculture is the farming of aquatic organisms with interventions
in the rearing process.
Impacts of fish farms
Impacts of fish farms include:
●➔ loss of habitats
●➔ pollution (with feed, antibiotics and other medicines added to the fish pens)
●➔ spread of diseases
●➔ escaped species including genetically modified organisms which may survive to interbreed with wild fish
●➔ escaped species may also outcompete native species and cause the population to crash. reducing biodiversity
the tragedy of the commons
the tragedy of the commons is when the selfish actions of the individual to exploit common resources affect society as a whole.
maximum sustainable yield (MSY)
A maximum sustainable yield (MSY) is the greatest amount of yield that can be exploited each year without depleting the original stock.
Water pollution
This is the contamination of a waterbody by pollutants either directly or indirectly.
Types of water pollution
Point source/ non-point source
organic eg human waste/ inorganic eg nitrates
Effects of water pollution
BLEW
Water borne disease
Eutrophication (pollutingfertilizers with phosphates)
Bioaccumulation/ Biomagnification in food chain
Lossof aquatic life
Measuring water pollution
- Biochemical oxygen demand (BOD) is 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 by microorganisms.
- Indicator species are plants and animals that show something about the environment by their presence, absence, abundance or scarcity.
- A biotic index indirectly measures pollution by assaying the impact on species within the community according to their tolerance, diversity and relative abundance.
Biochemical oxygen demand (BOD)
- Biochemical oxygen demand (BOD) is a measure of the amount of dissolved oxygen required for decomposers
- increased demand is bad = eutrophication
Indicator species
- Indicator species are plants and animals that show something about the environment by their presence, absence, abundance or scarcity.
biotic index
The biotic index provides a measure of water quality using indicator species
Eutrophication (phosphate caused)
Eutrophication is when excess nutrients are added to an aquatic ecosystem.
Impacts of eutrophication
Oxygen deficient water
death of fish and plants
increased cloudiness of water eg turbidity
The process of eutrophication
. Fertilizers wash into the river or lake.
2. High levels of phosphate in particular allow algae to grow faster
(as phosphate is often limiting).
3. Algal blooms form (mats of algae) that block out light to plants beneath them, which die.
4. More algae mean more food for the zooplankton and small animals that feed on them. They are food to fish which multiply as there is more food so there are then fewer zooplankton to eat the algae.
5. Algae die and are decomposed by aerobic bacteria.
6. But there is not enough oxygen in the water so, soon, everything dies as food chains collapse.
Strategies to reduce eutrophication
Ban use of phasphates
Educate farmers about better farming methods
Plant buffer zones to prevent wash away of fertilizer into water bodies from farms
