Deep-Sea Habitats in the Mariana Islands I

While exploring the abyssal plain with ROV Little Hercules, we observed numerous raised spirals and other shapes in the seafloor sediment. While they may resemble deep-sea crop circles, these patterns are actually fecal casts from acorn worms and other similar species. The bottom feeders will consume nutrient-rich sediment as they turn themselves, leaving a spiral trail of processed mud behind before heading off to find another place to dine and digest.