Hello,

I really need a clarification for this. I searched it already in Google but cannot find any results that answers my question.

The question is

Some of my friend try to breathe the aquarium using a straw just for a while and for entertainment. I know my English is bad but I hope you do understood what I am trying to say.

I remember that when we inhale, we get oxygen. When we exhale, we out carbon dioxide. So same from what's happening in the aquarium. My friend is not helping the fish instead killing it.Because he is just breathing out carbon dioxide on the water instead of oxygen that a fish needs.

One more question, I have read somewhere that oxygen is needed of all the living things. However, it came to my mind that trees, plants rather, don't need oxygen because they need carbon dioxide to live and then breathe out oxygen, opposite to a men'.

Please help me.

 

One more question, I have read somewhere that oxygen is needed of all the living things. However, it came to my mind that trees, plants rather, don't need oxygen because they need carbon dioxide to live and then breathe out oxygen, opposite to a men'.

Please help me.

Where is the first question ?

From Wiki: " For the majority of plants to grow successfully they also require oxygen in the atmosphere and around their roots for respiration. However, some plants grow as submerged aquatics, using oxygen dissolved in the surrounding water, and a few specialized vascular plants, such as mangroves, can grow with their roots in anoxic conditions."

http://en.wikipedia.org/wiki/Plant

There are anaerobic organisms that don't need oxygen, or even die if exposed to it. http://en.wikipedia.org/wiki/Anaerobic_organism

 

OK, animals use oxygen and use it to burn sugars and other compounds to generate energy. When we exhale we don't exhale pure CO2, because we aren't that efficient at burning the O2 (how oxygen is found in nature). Our breath leaves richer in CO2 than it takes in, but that is it.

Plants use sunlight and CO2 to make sugars and biomass, which they use to grow. In making this mass I think there is an excess of O2 left over, but I'm not sure about that. We eat the plants for their sugars and other nutrients. When we die they use our bodies for nutrients, as well as as our waste (crap and pee).

It is a true circle, we use them and they use us.

 

Your friend does not kill the fish by blowing into aquarium water. The amount of air we exhale contains about 14% oxygen instead of 20% O2 in the air we breathe in.

Even trees and plants need oxygen to survive. During the day when the process of photosynthesis is taking place, plants produce more oxygen than what they take in.

 

I found THIS interesting article explaining how the plant breathing works.

"In order to carry on photosynthesis, green plants need a supply of carbon dioxide and a means of disposing of oxygen. In order to carry on cellular respiration, plant cells need oxygen and a means of disposing of carbon dioxide (just as animal cells do)."

 

Fish can tolerate quite high levels of carbon dioxide as long as there is enough oxygen, it's produced by rotting vegetation and by plants and algae at night.
In aquaria with plants, hobbyists sometimes need to add extra carbon dioxide during the day:
http://www.aquariumfish.net/pages/co2_systems.htm

 

Are you sure your friend didn't see this link, and just told you he was breathing into the aquarium? http://st-james.hubpages.com/hub/1930s-College-Fun-Goldfish-Swallowing