Eutrophication (1 Viewer)

[tennille]

Hey, I'm really confused with eutrophication. What exactly is it? I know one of the textbooks gives the wrong definition which is stated in the marking criteria of last year's HSC exam, and I think I have that book. What is the difference between algal bloom and eutrophication? Is eutrophication the long term effect of algal blooms?

Also what are some of the tests to monitor possible eutrophication waterways? Is it nitrate and phosphate, BOD, DO, etc?

I'd really appreciate it.

 

[Xayma]

Eutrophication is (from memory) the increase of nutrients in a waterway, this can occur naturally such as when water begins to stagnate or artifically accelerated by things like fertiliser run off.

 

[sHin]

Google definition: Eutrophication

From what I've gathered from these definitions
1. Eutrophication is the long-term process in which a water ecosystem is destroyed.
i.e. organisms die due to lack of oxygen, pollution, acidity etc.
2. Enriched nutrient concentrations, algal blooms, and eventually oxygen depletion are causes of eutrophication. These factors aren't exactly eutrophication itself.

 

[Tommy_Lamp]

Excess nutrients stimulate excess growth of life-forms. These life-forms exceed the number that is sustainable by the ecosystem. Eventually the excess nutrients that are being pumped into the ecosystem are stopped and the ecosystem has to support the organisms, which it can't do, hence the ecosystem 'dies'.

 

[Xayma]

Google definition: Eutrophication

From what I've gathered from these definitions
1. Eutrophication is the long-term process in which a water ecosystem is destroyed.
i.e. organisms die due to lack of oxygen, pollution, acidity etc.
2. Enriched nutrient concentrations, algal blooms, and eventually oxygen depletion are causes of eutrophication. These factors aren't exactly eutrophication itself.

I don't see how you got 2. From multiple of those.

 

[sHin]

If I'm correct, the 2003 Marking Criteria is referring to the definition given by Conquering Chemistry. Nitratehosphate, OD, BOD, turbidity, H2S and CH4 levels can give an indication of eutrophication.

I don't see how you got 2. From multiple of those.

Well it was just a general consensus I came up with, and it's much more correct than what you stated, anyway.

 

[tennille]

I thought it was Conquering Chemistry. That's why I'm totally confused. It states that it's when the river eventually becomes a swamp, and eventually land.

Thanks guys.

 

[tina_goes_doo]

Yeah that was the definition the my tutor gave today. It seemed wrong to me and was the first time i heard anything like that before. I just thought eutrophication was when the nitrates and phosphates from fertilisers wash into the waterways and stimulate algal growth.

 

[smallcattle]

so what exactly is the definition of it?????

and for HSc2003 Q26 how should i answer it

should i say testing ion concentration, turbidity, concentration of acid to test the water quality??

 

[Paroissien]

From Collins English Dictionary:
Eutrophication: a process by which pollution from such sources as sewage effluent or leachate from fertilised fields causes a lake to become overrich in organic and mineral nutrients, so that algae and cyanobacteria grow rapidly and deplete the oxygen supply.

Therefore eutrophication is a lake becoming overrich in things like phosphate and nitrogen, and algae growth is simply a result of eutrophication, not eutrophication itself.
And regards Q 26 just monitor the N ratio, DO and BOD

 

[persephone]

Eutrophication results from the addition of nutrients, such as phosphates and nitrates from fertilisers, into waterways. These cause a bloom in algal populations which subsequently use up the dissolved oxygen in the water and eventually block out sunlight from all but surface waters. Both of these factors lead to the demise of the algae. The dead algae provide the right conditions for decay bacteria and cyanobacteria to thrive and release toxins into the waterway leaving it devoid of animals and plants and unusable by humans for many years.

..sample answer from somewhere....

 

[Tommy_Lamp]

Increased nutrients, abundance of life-forms, oxygen used up, life-forms die, form sludge on bottom of water, process repeats, eventually waterway disappears

 

[svenny]

This is in another forum... but here is what i wrote

Eutrophication isnt that hard to understand.

Basically when you have a waterway that is full of phosphates and nitrates (be it from sewage or run off from waste detergents) it encourages plant growth, simply because the phosphates and nitrates are nutrients for the plants.

Secondly with the excess plant growth you get "algal bloom" (which means that you have lots of plants in the waterways). This obviously leads to 2 other things

1 - it leads to less sunlight in the body of water
2 - It also means that there are more plants fighting for the oxygen.

Because there is less sunlight AND more plants, we find that the oxygen levels in water decrease to a very low level, and this leads to some micro organisms (and even fish) dying in the waterways, and then also the plants die too cuz there is no oxygen for them to photosynthesise with.