Human Impact on the environment

Question 1

If trees are cut down from a forest with machinery, how volume this increase the concentration of co2 in the atmosphere?

Answer 1

• Combustion of diesel fuel by machinery releases CO2 gas into the atmosphere
• Lack of trees means less photosynthesis to fix co2 (so less CO2 being used up
• Discarded plants/branches/leaves/debris gets decomposed by saprophytes

Question 2

What are the effects of human activities on the carbon cycle?

Answer 2

-Deforestation
-Climate change
-Global warming
-Ocean warming

Question 3

How does deforestation affect the carbon cycle?

Answer 3

•Increases the carbon dioxide content in the atmosphere:
aremoval of trees so less uptake of CO2 from the atmosphere due to less photosynthesis.
-Plants store carbon as biomass so burning the woody parts of trees releases carbon dioxide into the atmosphere.
-Forested is replaced by crops which store less carbon dioxide and when crops die, decomposers undertake decay, releasing carbon dioxide.
-Forest is often replaced with cattle that produce high levels of carbon dioxide and greenhouse gases such as methane.

Question 4

What is the cause of climate change and what is the reason?

Answer 4

-cause is thought to be the huge rise in atmospheric carbon dioxide levels and the rise in other greenhouse gases e.g. carbon dioxide, methane, nitrous oxides and water vapour.
-The two main reasons for the rise in carbon dioxide are combustion, the burning of fossil fuels releases carbon dioxide that was previously locked up and deforestation.

Question 5

How has carbon dioxide lead to global warming and what has this caused?

Answer 5

-CO2=important greenhouse gas, as it absorbs radiation from the Earth. If it accumulates in excess, it leads to global warming.
-resulted in increased frequency of extreme weather conditions, polar ice caps melting and an increased frequency of forest fires.
-Consequently, species distribution may change; plants and animals may be driven to extinction if they cannot find a suitable new habitat fast enough, which reduces biodiversity.
-In some regions, there may be increased crop yields, but pest populations may also increase.

Question 6

How does ocean warming link to CO2?

Answer 6

Oceans can store a lot of heat so there is a time lag between warming of the atmosphere (which Is linked to global atmospheric CO- levels) and the warming of the ocean.

Question 7

What does an increase in CO2 levels in water result in?

Answer 7

-CO2 + H2O= H2CO3
-this means increase in H+ so decrease in pH
-so water dissolved shells/skeletons

Question 8

What are some consequences of global warming and climate change on aquatic habitats?

Answer 8

• Decreased pH (acidification) of oceans - corals die, damages molluse shells
• Increased rates of photosynthesis in aquatic habitats causing aIgal blooms
• Less oxygen dissolved in water at higher temps
• Fish migrate to cooler waters
• Reduced productivity on fish farming industry