Fresh Water Ecosystems Flashcards
What are the key physical and chemical properties of fresh water systems?
Density, viscosity, flow, velocity, depth, light, temperature, dissolved oxygen, carbon dioxide, pH and Nutrients
How much total water on the plant is fresh water?
Only about 3%
What percentage of freshwater is located in accessible fresh water locations?
1%
What percentage of accessible freshwater systems are rivers?
1%
How does density vary in water?
Varies with temperature and salinity
Why does viscosity effect a stream?
Different animals can tolerate different levels of viscosity
Who developed the chart to see how viscosity effects animals?
Reynolds number ratio of inertial
How does drag effect a large object?
Drag is much less than pressure
How does effect a medium object?, eg a fish
Pressure and drag both equall
How does drag effect a small object?
Drag and viscosity much more important that pressure
Why do rivers exist?
Fastest way for runoff water to reach its level, eg an ocean
What is viscosity?
Resistance of a fluid to sheer stress
What is a lot if system?
A river, moving water
What is a lentil system?
Lakes, standing water
Where is depth much more important?
Lakes rather than rivers
What is water temperature dependent upon?
Origin, groundwater, surface run off, glaciers, tributarys, air temp. Season. Time of day. Water depth and discharge
How can could clouds change water temp?
Longwaves emitted. Insulation
What exchange is there from the river and groundwater?
Hyperthermia exchange
What is the friction called that acts on rivers?
Fluid friction
What is the average groundwater temp in the uk?
11 degrees Celsius
What is the relationship like between air and water temp?
Strong
What can be said about air temp compared to water temp?
It is more unstable
When does air and water temp not have a strong relationship
When freezing
What effect can ice have on river organisms?
Physical impacts on bilogical communities like freezing or damage
What is frazil ice?
Ice rivers that flow, goopy and often stops
How does origin of water effect temperature?
If it comes from a glacier it will be colder, karstic will also be cold
Does water temperature decrease downstream?
Yes
Why are topography and river vegetation important?
Influence temperatures, eg shading, slowing down water
Why has the river Trent shown a decline in temp?
Due to factories being closed on the river
What impact can water temperature have on salmon development rates?
Can slow growth of eggs of water is is colder
What is a bivoltine animal
One that has two generations in one year?
Why happens with the two different life cycles in a mayfly population?
Due to different temperature one cycle is much slower than the other, the greater this temperature difference the more different these life cycles are
What can effect DO in water?
Temperature and altitude
What happens with ionic compounds with temperature increase?
Warmer temperatures mean ionic compounds have greater solubility
How is DO normally measured?
Concentration (mg/l) or % saturation
What adds DO to the river system?
Plants, animals, mainly planktons or fish
What takes away DO from the river system?
Bacteria, dissolved organic matter
What is the ecological significance of dissolved oxygen?
Species need oxygen to survive, when salmon lay eggs. They do so in a way that most oxygenated water passes over the egg
What species are adapted to deal with low oxygen?
Insects, caddisfly, worms ect
What affect does pollution have on oxygen?
Changes it’s content, normally decreases it leaving areas of poor oxygen quality and amount
What happens to animals downstream of pollution?
Different specs live and inhabit downstream of the pipe, think succession, better tolerators like closer to the pipe
How else can oxygen get into the water?
Turbulence mixing with air
What will a large object score with a Reynolds number?
Over 10
What will a small bacterium score on the Reynolds scale?
Less that 0.1
How do you work out Reynolds number?
Density x velocity x length divided by viscosity
What is a multivoltine animal?
It has multiple generations
Why is river accessibility important to salmon?
They move up and down to river so need access all along
Name two rivers to experience river temperature change recently?
Trent colder, Mississippi warmer
Why are riparian vegetation important on rivers?
It regulates river temperature
What happens with temperature with an open plains environment?
Warmer in summer, cooler in winter
What is more temporally variable a small or large river?
Small
Which rivers are more variable in a day?
Wide and shallow rivers
What relationship does DO have with water temp?
Inverse, as it gets warmer there is less oxygen
What does DO sat compensate for?
Temperature and altitude
What stage of the river does clean water animals inhabit after pollution?
D
Which stage of river pollution does sewage fungus flourish?
C
What is common at stage B in river pollution?
Amonium
What does carbon dioxide and water equal?
Carbonic acid
What is the pH of rainwater?
5.64
What is the avatar pH of river water?
4.5
What is common in rivers of higher temperatures?
Polar compounds, carbonic acid amino acids, carboxylic acids
What is less common in warm rivers?
Covalent compounds, fats and oxygen
What is buffering capacity?
Buffering from natural carbonates and bicarbinates, below 120 macroequivelemt there is no capacity and the pH will decrease
What are the main 2 nutrients essential to plant growth?
Nitrogen and phosphorus
What is the name for he diatom that is used for silica?
Frustule
What sediments store phosphorous?
Detritus and lake sediment storage
What is the ratio normally used between phosperous and nitrogen?
16:1
When is nitrogen considered to be limiting?
<16:1
What causes detrimental rapid plant growth?
Pollution causing higher phosphorous
