Answer:
Ecosystems are indeed capable of cleaning the earth's water, and they do so through a variety of natural processes such as filtration, absorption, and biodegradation. However, when it comes to using water for human needs and consumption, the issue is not so much about the effectiveness of these processes, but rather the scale at which they can be implemented.
Natural ecosystems have limited capacity for water purification, and are not always able to cope with the large amounts of pollutants and contaminants that human activities introduce into the water supply. Moreover, many of these natural systems have been damaged or destroyed by human development, leaving fewer options for natural water treatment.
In addition, natural systems can take a long time to purify water, and the water may not be suitable for immediate use. This can be a challenge in situations where clean water is needed urgently, such as during a drought or a disaster.
Therefore, while it is important to protect and restore natural ecosystems that help to clean our water, we also need to develop and invest in technologies that can help to purify water on a larger scale, such as water treatment plants, desalination plants, and advanced filtration systems. By combining natural and technological approaches, we can ensure that we have a reliable and sustainable supply of clean water for human needs and consumption, while also protecting the health of our natural ecosystems.