The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

Biology Question

A dairy farmer washes out his cow shed each day. The waste water contains urine and faeces. The waste water overflows inti a stream by mistake.
The waste water will have an effect on the plants and invertebrates living in the stream.
Explain why.
(6 marks)
Could you provide some part of your thought process/etc to the question? That'll help folks help you. I mean, you can Google the answer to virtually any question that has been answered or made, but going on a forum and posting one is moreso to get help with your own answer to the question and the struggle to get there.

Either way, here's a starting point to consider: Consider what faeces contains, and what urine contains. Nutrient and element, wise :P
I thought that when the faeces decompose the would release methane but im not sure what exactly that would mean. The faeces would also acts as a fertilser for the plants because of the nutrients in them so that more plants would grow and faster. This would mean that the populations of invertebrae that eat these plants would also increase.
I also came up with negative effects but im feel like these contradict what i said before.
So the faeces may contain bacteria like E.Coli for example which would make the invertebrae populations die out if they ingested it (and lower the O2 levels in water by respiring maybe?). It would also pollute the water making it cloudy so that less light could reach through to plants so that they do not recieve enough to photosynthesise properly and they decrease so invertebrae also decrease.
The urine that contains urea is slightly acidic so would lower the pH of the water and mean that enzymes in working in plants wouldnt work as efficiently.
Also if urea ingested and builds up in animals would poison systems of invertebrae?
Original post by someone1928
I thought that when the faeces decompose the would release methane but im not sure what exactly that would mean. The faeces would also acts as a fertilser for the plants because of the nutrients in them so that more plants would grow and faster. This would mean that the populations of invertebrae that eat these plants would also increase.
I also came up with negative effects but im feel like these contradict what i said before.
So the faeces may contain bacteria like E.Coli for example which would make the invertebrae populations die out if they ingested it (and lower the O2 levels in water by respiring maybe?). It would also pollute the water making it cloudy so that less light could reach through to plants so that they do not recieve enough to photosynthesise properly and they decrease so invertebrae also decrease.
The urine that contains urea is slightly acidic so would lower the pH of the water and mean that enzymes in working in plants wouldnt work as efficiently.


You've got the right idea here. If you break it down into stages, then the likely effects are clearer.

First, the content of the waste products washed into the stream will be rich in nitrogen and organic matter.

The organisms first in line to utilise this will be bacteria and algae in the water. With this extra nutrient source, they will proliferate and, through their aerobic respiration, the oxygen in the water will quickly become depleted.

The result will be an algal and bacterial "bloom", and a die-off in the other organisms (such as invertebrate, fish and plant life) as they no longer have enough oxygen. The bloom may also - as you say - make the water cloudy and reduce the amount of sunlight penetrating the water, further causing photosynthesising plants to die off.

In the long term, if the source of pollution is removed, and plenty of oxygen continues to enter the waterway, then gradually, the community will restore itself. If not, there will tend to be a long term problem with recurrent algal blooms and impoverishment of the ecosytem. This "eutrophication" is a big ecological problem worldwide (not just from pollution incidents, but from long term use of nitrogen and phosphate fertilisers on the soil, which eventually leach out of the soil and into waterways.

PS Your ideas about methane and acidification are not wrong, but they are long term consequences which are less likely to be as significant as the immediate eutrophication effect
(edited 5 years ago)
the things he uses to clean the shed

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you