The diagram shows part of a river into which sewage is being pumped. Some of the effects of adding sewage to the river are shown in the graph. At which point in the river are decomposers most active?

Question

Philoid · Accepted Answer

At B the concentration of blue green algae is high, they take up the atmospheric oxygen and then the nitrated bacteria convert it into ammonia, so that it can be used by aquatic environment. In this way they release nutrients back into the environment for other organisms to use.

Also because of high concentration of Oxygen at B point, helps them to use oxygen to gain energy and drive their own life processes. They will again make the water fresh and clear.