How oxygen replace in night when plants also respire and no photosssyntheis?

As photosynthesis produce oxygen during tat and absorbed carbon di oxide then it is understandable that here is a constant recycling of oxygen. But in night when no photosynthesis then what will happenb? please answer one more why birds klive safely whereas there mudst be higher carbon dioxide concentratio in night time.



  1. 0 Votes

    Plants, like animals, take in oxygen during the day and the night, and expel carbon dioxide.  You are correct that during the day, photosynthesis allows plants to emit oxygen as well, and without the daylight, no oxygen is produced.  However, the amount of oxygen plants take in whether day or night, and the amount of carbon dioxide they produce is minimal.  There is no output of carbon dioxide significant enough that it would be noticeable to people or animals.  

    • 0 Votes

      Thanks for the answering. but its not a satifying answer to me. Actually i want to know from where we get oxygen in night or cloudy days when no photosynthesis. or you can say hows the amonunt of oxygen remain constant in atmosphere when there is no photosynthesis. waiting for reply thanks with regards

    • 0 Votes

      Ah! You are thinking globally, and I was focusing on smaller things such as houseplants.
      Remember that when it is night or cloudy in one part of the world, it is likely to be daytime or sunny in another. The oxygen in the air in Brazil is not due just to the plants in Brazil, but to forests and jungles all across the globe. Think about the polar ice caps and countries where virtually all the vegetation dies or hibernates in the winter, they have oxygen too. Here in Chicago we still have oxygen when everything is covered in snow. Thanks to vast tropical forests, and all the rich vegetation closer to the equator, there is always oxygen being produced somewhere, and air is circulating all around the globe at all times.
      In our vast oceans, cynoplankton (such as algae) and plankton produce oxygen constantly, and are responsible for up to half the atmospheric oxygen today. Also, water molecules break up into hydrogen and oxygen in the atmosphere, and while the hydrogen is released into space (it is much lighter), the oxygen remains in our air. This is a small percentage, around 2%.
      It is also important to know that the air we breathe is primarily nitrogen, only 21% of breathable air is oxygen, so plants are not responsible for providing all of our air, just the oxygen in the air.
      I hope that helps!

    • 0 Votes

      thanks alot dear karma to solve my confusion. thanksonce again.

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