In this article, it talks about how nearly every body of water contains microscopic organisms that live attached to rocks, plants, and animals. These sessile suspension feeders are critical to aquatic ecosystems and play an important role in cleaning up environmental contaminants by consuming bacteria. A study reveals that by changing the angle of their bodies relative to the surfaces, these feeders overcome the physical constraints presented by underwater surfaces, maximize their access to fresh, nutrient-rich water, and filter the surrounding water. So basically, sponges help filter and clean water and they can also help detect the amount of pollutant and other things affecting the water.