16. Acidification Of Freshwater Flashcards
What is the normal pH of rainwater?
5.6
What causes anthropogenic acidification?
The burning of fossil fuels and wet and dry deposition of acid
What combines to form the weak rain water acid?
Carbon and h2O, carbonic acid
When are we describing acid rain?
Where pH is less than 5.6
What is the average rainfall of US and Central Europe?
pH between 4 and 5
What are the main generators of acids rain?
Coal burning, planes, cars
What comes from industrial pollution?
SO2 and H2S, makes sulphuric acid
What pollution comes from cars?
NOx from car exhausts, forms nitiric acid
What effect does land have on acudification?
Land use can enhance acid rain eg deforestation
What do trees pump out?
Hydrogen ions to take in the ironing exchange
What is dry deposition?
Trees absorb gases into vegetation
What is wet deposition?
Rainfall of acid,
How can wet deposition be buffered?
By limestone
Where do we get accumilation of acids
Where we have hard surface rocks, eg granite
When do we get sensitive soils
Where the area lacks limestone
What is surface acid pollution exceserbated by?
Land use
What do added trees do to rivers?
Increase acidity, leaf litter
What is the problem with farmers making ditches for tree runoff?
Increases runoff speed, flashy systems
What nutrients do trees take up?
Ca2 that ones needed to buffer the soils
As places become more acidic what comes into solution?
Metals, more common
What do the metals do in the water?
Sucks up all of the nutrients
What are the main fish we associate with acidification in the uk
Brown trout and Atlantic salmon
When does pH start becoming harmful to fish
When it’s less than 5, can damage eggs and fry
Why does acidification damage fish?
Impacts the gills, active transport less productive, loss of sodium ions
What happens to fish numbers and acidification?
Fish numbers rapidly decline
What invertebrates do well in acid streams?
Careless Caddisfly
What is the general trend in macro-invertebrates
Loss of diversity
What level of acid can a fresh water shrimp tolerate?
Not below 7pH
Why are crustations hevaily effected by acid?
Body tissue is rich in calcium
What are the most tolerant invertebrates?
Stone flies, can tolerate down to 4pH
What are aquatic fungi called in fresh waters?
Hyphomycetes
What do Hyphomycetes do in rivers?
Decomposes detritus
Why are algae good for analysing streams?
Each specific algae lives in a preferred condition meaning we can use them to see past events
What happens when we loose fish in streams?
Large invertebrates become dominant, algae is depleted
What are the majority life forms in an acid stream?
Diatoms and cocci is greens
What dominates invertebrates in a neutral stream?
Grazers
What dominates a stream in a acid environment?
Shredders
What is it called when water quality changes to be better but communities stay the same?
Inertia
What can be added to streams to turn it back to the acid levels previously?
Liming
What is secenario a to why streams might not recover?
Colonists adobe but do not persists, innaproiate habitat, chemical restrictions, recsouce limitation, competition
What is scenario b
Colonists not arriving at sufficient rate, geographic isolation of recovering sites, limited dispersal abilities
What is the main acid in wet acid deposition?
H2SO4, HNO3, dissolved mostly into rain and snow
What damage can acid rain have?
Can effect structure made of limestone and other easily erodible structures
What makes a soil sensitive?
Lack of buffering rocks such as limestone
Name an area with extremely sensitive soils?
Scandinavia
What happens when ionic change in the soil where soils are poor in calcium and magnesium
The release of aluminium
What characterises why areas in Scandinavia have pool acid buffering?
Granitic, thin and patchy soils and very soft waters
How do we quantify acidification?
Pre acidification alkalinity- present day alkalinity
What is the pH limit for crayfish?
6.8
How much of the cray fish pinail population will be lost by 2060?
20%
What is the main acid in wet acid deposition?
H2SO4, HNO3, dissolved mostly into rain and snow
What damage can acid rain have?
Can effect structure made of limestone and other easily erodible structures
What makes a soil sensitive?
Lack of buffering rocks such as limestone
Name an area with extremely sensitive soils?
Scandinavia
What happens when ionic change in the soil where soils are poor in calcium and magnesium
The release of aluminium
What other fresh water animals is effected by a lack of calcium?
Snail, Gastropoda
How many tail do stone fly’s have?
2
How can we identify the microbial fungal in streams?
In the bubbles
What changes the likelihood of a specific auto trophic community?
pH
What is the cell wall of a diatom
Silica/glass
What diatom is only found in acid streams?
Eunotia
Where can acid come from geologically?
The rocks in the river
What happens in acid stream with algal quantity?
It increases due to lack of invertebrates feeding from it
Why is acidification a problem for calcium fixing speices
increase in co2 leads to diminution of carbonate ions leading to less calcium for species
What is the problem if a calcium fixing animals cannot find enough calcium
not enough calcium for molting, shell becomes weak and does not protect them
Where do cray fish store potential calcium
gastroliths
What service do cray fish supply to the river
water cleaning by feeding on dead material
