Where do deep-sea creatures live? Where they won ’t dissolve

Vast muddy seabeds cover more than 60% of the planet, collectively making them Earth’s largest habitat. At first glance, these frigid, sunless depths all seem more or less the same. Yet the animals that live there, kilometers below the surface, prefer some regions over others, according to a new study. What accounts for their preferences? It’s nothing they can see or sense, the authors say, but an invisible and life-threatening limit imposed by seawater chemistry. This limit demarcates where an important component of many kinds of marine life, calcium carbonate, naturally dissolves. Researchers have long known that microscopic, shelled creatures called forams will vanish under these inhospitable conditions. The new work suggests this restriction on carbonate could also influence where larger animals live. “It’s remarkable,” says Mark Costello, a marine ecologist at Nord University who was not involved with the work, reported today in Nature Ecology & Evolution . “This [limit] will be a major driver of biodiversity in the deep sea everywhere.” It could also drive new discussions surrounding the regulation of deep-sea mining, the authors note, which represents a controversial and looming threat to life on abyssal plains. Almost a decade ago, Erik Simon-Lledó, a marine ecologist with the U.K. National Oceanography Centre, began to study the diversity of life in the Clarion-Clipperton Zone. That’s the part of the abyssal plain i...
Source: ScienceNOW - Category: Science Source Type: news