Bio 346 - Freshwater Eco. (Chpt 27) --> Acidification of Waterways Flashcards
Aquatic acidification
Decrease in the acid neutralizing capacity (ANC) of waterways
What are the leading 2 influences of aquatic acidification?
- Industrial
2. Mining
What determines how systems respond to acidification??
Geology of waterways
What causes specie loss or change in abundance?
H+ deposits directly on water surfaces and the indirect effects of high H+ [ ] on catchment soils and vegetation
What do high levels of H+ [ ] lead to?
Release of metals from soils and their subsequent stream transport to the receiving lakes and wetlands
- Can be harmful to humans/wildlife who are drinking the water
What are 3 ways that people are indirectly affected by the death of natural resources?
- Loss of desirable fish or invertebrate species
- Loss of forests
- Irreparable damage
What do buffered drainage basins do?
Help to resist acidification
What 2 chemicals are released during combustion of coal, oil and gas?
- Sulphur dioxide
2. Nitrogen oxides
What is an example of long distance transport?
Atmospheric residence
- can travel up to 400km in a day
What is en example of wet deposits?
Rain or snow containing compounds
What is an example of dry deposits?
Aerosol or gases
- Hard to accurately determine
What is the pH of normal rain compared to acid rain?
Normal rain = 5.5-6
Acid rain = 4 or lower
What causes the pH to drop in rainfall?
heavy human impact
What is the cause of H2CO3 in the atmosphere?
Volcanic sources
What NH3 is released, what does it produce? And what does it do?
Produces OH that neutralizes atmospheric H+
What 3 things is aerosols made from?
- Ammonia (NH3)
- Sulphuric acid (H2SO4)
- Nitric acid (HNO3)
What does the reaction of aerosols consume?
H+
What was the cause of the doubling of emissions of SO2 and NOx in the 20th century?
Burning coal and fuel oil for electricity
Where does NOx come from?
Internal combustion engines (fossil fuels)
What type of lakes are most sensitive to acidification?
3 things
- Transparent
- Low salinity
- Low acid neutralizing capability
What does chemical sensitivity indicate?
That a small amount of acid produces a large decrease in pH
What does ecological sensitivity indicate?
That small addition of acid will result in biological changes
A small change in what, can make a huge effect on acidification?
pH
- Most sensitive with a ph between 5-7
What happens to the sulphur and nitrogen oxide deposition rates as distance increases?
Decreases
Paleolimnology
Studies the relationship between algal communities in sediments and pH have been developed to hindmost pH
What 2 factors influence the decrease in pH?
- Geology
2. Deposition rates
What 4 things is susceptibility to acidification affected by?
- Ability of catchment soils and rock to neutralize acids
- Lake morphology and catchment attributes
- Organic acids in runoff
- Neutralizing agents and precesses in the system
What does ANC stand for?
Acid neutralizing capacity
High ANC
Large fraction of catchment covered by easily weathered rocks and soil
Low ANC
Glaciated areas with highly insoluble bedrock
What can increase ANC?
Calcareous drift from glaciers
When surface soils are of igneous origins (low ANC), what 3 things are susceptibility determined by?
- Lake morphometry
- Catchment attributes
- Atmospheric dust (CaCO3)