When you see a puddle on the street, or a flowerpot full of rain, it’s natural to think this water is separate from the ocean. After all, it’s miles from the coastline. The way we treat water that far inland shouldn’t have an effect on a marine ecosystem such a distance away — but it does.
In truth, all of the earth’s water is connected. The water cycle is a series of linked processes turning in an endless loop, from evaporation to precipitation and runoff. A seemingly harmless action may have consequences elsewhere, and large-scale mismanagement of water can result in serious threats to the ocean.
To visualize the idea, consider the path of a stream. The stream will eventually lead into a river, and the river will eventually lead into the sea. If someone pollutes the stream, it has far-reaching implications beyond the stream itself, causing issues as the contaminants travel toward their inevitable destination.