Answer:
Through pollution and uncontrolled and untreated discharge of waste into river bodies.
Step-by-step 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.