Answer:
1) The tiny animals would not have enough food.
2) Fish would not have enough oxygen.
Explanation:
If algae is removed from the marine ecosystem, all the ecosystem will be disturbed because algae are the producer which produces two materials i. e. oxygen and food for tiny organisms. If algae are removed, tiny animals die because of hunger. Oxygen concentration is also lower when algae is removed from the ecosystem and this decrease in oxygen concentration causes suffocation and the fishes are die.