Human Impact on the Environment Flashcards
Describe eutrophication and how it is caused
Caused by algae blooms from fertilisers. These algae blooms block sunlight from reaching the aquatic plants lower down, which then die and are broken down by microorganisms. These microorganisms then use up all the oxygen in the water, causing the larger animals to suffocate.
What is leaching and how is it made worse by inorganic fertilisers
Excess fertilisers are washed into the water systems and into lakes and rivers causing eutrophication. Inorganic fertilisers tend to be more soluble and so wash away more easily
What is a biological oxygen demand and how is it measured
A measure of the amount of dissolved oxygen microorganisms used to break down decaying matter. The higher the BOD, the more polluted the water. It is measured in the dark to prevent photosynthesis from countering the correct figure
What steps must farmers take to reduce leaching
Restricting the use of fertilisers
Only applying fertilisers while plants are growing
Dig drainage ditches
Leave a strip unfertilised near any water sources
Name some effects of climate change
Rising sea levels Glacier retreating Mass species extinctions Increased range of diseases Extreme weather
Name natural causes of global warming
Deforestation and combustion
Name domestic causes of global warming
Use of fuel for transport and electricity for cooking/heating
Name industrial causes of global warming
CO2 is widely released from factories as a by-product, and methane is released from farming
Issues with monoculture farming
Growing a single crop on a large scale means shrubbery and hedges must be removed to make way for crops thereby reducing biodiversity
Factors increasing the number of endangered species
loss of habitat over hunting deforestation pollution competition from alien species
Steps taken to conserve species
Nature reserves Captive Breeding programmes Hunting bans Global charities, WWF Seed Banks
Why does deforestation occur
Fuel Farming Houses Paper and Packaging Palm Oil
Actions taken to reduce deforestation
Coppicing
Selective Cutting
Ecotourism
Long rotation time
Solutions to overfishing
Exclusion Zones
Catch Quotas
Fishing Efforts limits
Problems with fish farming
Relies on the use of pesticides
Disease spreads quickly
Food and biological waste causes eutrophication
Advantages and disadvantages of biofuel
Advantages - Renewable, cheaper than petrol, can be manufactured from a wide range of sources
Disadvantages - Lower energy output, uses up agricultural land, uses up large amounts of freshwater
Name the planetary boundaries
Climate Change Biosphere Integrity Land system change Biogeochemical flows Stratospheric ozone Ocean Acidification Fresh water use Atmospheric aerosol loading Novel Entities
Climate change boundary
This boundary has been crossed because of the levels of greenhouse gases emitted in recent years
Biosphere integrity (biodiversity) boundary
Core boundary that has been crossed because of high levels of habitat destruction, pollution, poaching and climate change
Land system change boundary
(The way land is used) Deforestation for agriculture and housing
Biogeochemical flow boundary
(Nitrogen/carbon cycle) Overuse of fertilisers as well as deforestation and combustion
Stratospheric ozone boundary
We reversed crossing this boundary by banning CFCs which are responsible for causing the erosion of the ozone layer
Ocean acidification boundary
pH has fallen by 0.1 causing issues for sensitive aquatic organisms, particularly those with calcium based shells
Fresh water boundary
Overuse of fresh water causing diminished stocks in reservoirs. Caused by population increase, deforestation, climate change and water pollution
Atmospheric aerosol loading boundary
Increased pollution of the air from fossil fuels and dust from quarries, worsening conditions like asthma and emphysema
Novel entities boundary
Pollution from radioactive and nano materials. Some chemicals have been banned due to their toxicity such as DDT, and it can cause bioaccumulation
What is bioaccumulation
Increase in concentration of pollutant in a single organism from the organisms it ingests
What is biomagnification
Increase in concentration of a pollutant in an entire food chain
What bacteria carry out decay
Saprophytes
What are denitrifying bacteria called
pseudomonas
What are nitrifying bacteria called ammonium -> nitrite
nitrosomonas
What are nitrifying bacteria called nitrite -> nitrate
nitrobacter
What are nitrogen fixing bacteria called
rhizobium
