Meet the chicken kidney sponge, a true ecosystem engineer that could use its filter-feeding power to clean the degraded habitats in and around busy harbors. Sponge populations offer a potential natural way to clean up these dirty ports. Three specimens of the chicken kidney sponge transplanted into the harbor. Chicken kidney reigns supremeThe chicken kidney sponge C. reniformis stuck out among all of the sponges tested as the best candidate for future clean-up experiments. They particularly want to track the communities of microbes present in the chicken kidney sponge to see if these microscopic organisms help them tolerate pollutants.