Q1.
Oceans give us almost half the oxygen we breathe. Tiny marine organisms, such as plankton, make this possible. What do you think would happen to all living beings if pollution harmed these planktons, and they could no longer produce enough oxygen?
Answer
Life on land and in the sea would be hit twice over — once through the air, and once through food.
- Less oxygen in the air and in the water. Plankton have chlorophyll and use sunlight and carbon dioxide to make food, releasing oxygen as they do. If they die back, roughly half the world’s oxygen supply weakens. Fish and other sea animals, which breathe oxygen dissolved in water, would suffer first and fastest, because the water around them loses its oxygen long before the atmosphere does.
- The whole ocean food chain collapses from the bottom. Plankton are the first link — small fish eat them, larger fish eat the small fish, and the largest mammal in the world, the blue whale, feeds on plankton directly. Break the first link and every link above it starves. Reefs, already under stress, would lose the fish that live in them.
- More carbon dioxide stays in the air. Every plankton that is not there is carbon dioxide that is not taken out of the water and the air. Warming would speed up, which in turn warms the ocean and harms the surviving plankton further.
- People lose food and livelihood. Fishing communities along the Indian coast, in the Bay of Bengal and everywhere else depend on those fish. Coastal towns would lose their catch, their trade and their work.
Why it happens: the danger is not that plankton are important animals — it is that they are the base of two systems at once, the oxygen system and the food system. A living system can usually survive losing something at the top, because the layers below reorganise. It cannot survive losing the bottom, because there is nothing below to replace it. That is why pollution that seems to harm only ‘tiny organisms nobody sees’ is among the most dangerous kinds.
Tip: Plankton are harmed by exactly the wastes we control — sewage, farm chemicals washed into rivers, oil spills and plastics that block sunlight. Protecting them starts on land, not at sea.