When the ecosystem is polluted with large pieces of plastic waste, the amount of microplastics slowly increases.Explain why this happens.

When large pieces of plastic waste enter an ecosystem, they don't biodegrade like organic material. Instead, they slowly break down into smaller and smaller pieces through a process called photodegradation. This is primarily driven by exposure to sunlight, which breaks the bonds in the plastic's polymers.

1. Exposure to Elements: When plastic waste is exposed to the elements (sunlight, wind, rain, etc.), it starts to break down. This is not biodegradation (where organisms in the environment break down materials), but photodegradation.

2. Photodegradation: In photodegradation, the UV radiation from the sun breaks the bonds in the plastic's polymers. This process is slow and can take many years.

3. Formation of Microplastics: As the plastic breaks down, it forms smaller and smaller pieces. When these pieces are less than 5mm in length, they are referred to as microplastics.

4. Persistence in the Environment: Microplastics are so small that they can be carried by wind and water currents, spreading throughout the ecosystem. They can also be ingested by wildlife, causing harm to these animals and potentially entering the food chain.

5. Increase in Microplastics: Over time, as more and more plastic waste enters the ecosystem and breaks down, the amount of microplastics in the environment increases.

So, the pollution of ecosystems with large pieces of plastic waste leads to an increase in microplastics over time due to the slow process of photodegradation.