That’s a vivid image. First, we’d sample systematically, taking water and sediment from many points, then use a laser‑based microscope or high‑resolution imaging to count and size each fragment—like surveying a city block. The data could be plotted on a georeferenced map, with color codes for polymer type and age, so the “metropolises” pop up on a heat‑map. Then, to tell the story, we combine those maps with ecological data—fish populations, coral health, human use—and present it in an interactive dashboard or a narrative video. It turns raw numbers into a story of how these tiny cities alter marine life and, eventually, our own well‑being.