Explain how human activity can impact the limiting factors of river ecosystems.

Through pollution and uncontrolled and untreated discharge of waste into river bodies.

Explanation:

Some of the common limiting factors of any water ecosystem are -  

a) turbidity,  

b) temperature,  

c) pH level, and  

d) dissolved oxygen

Human activities have interfered with the water ecosystem adversely. The water pollution has affected all the limiting factors of river ecosystem .  

Addition of pollutants from industries and sewage system increase the turbidity of river water.  

The temperature of river ecosystem also increases because of the increased organic productivity of the rivers . This happens due to discharge of organic matter in river ecosystem.

pH are also destablised by addition of industrial and sewage effluents

And dissolved oxygen also reduced because of increased organic productivity of river ecosystem.  

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.