#oceanfloor

#oceanfloor

The Damage a Ship's Anchor Can Do to the Sea FloorShips have been sailing the world's oceans for hundreds of years, dropping anchor anywhere they stop for any length of time. Anchors keep the ships from drifting away while at port, and we've never put much thought into what marks they left at the bottom of the bay. But ships today are different from what we envision as "sailing." Massive container ships that are bigger than aircraft carriers have anchors that strain credulity. A container ship anchor weights between 5,000 and 30,000 pounds, and rely on chains with 3-foot links weighing 200 to 500 pound each! It's not just those heavy anchors that damage the sea floor. Those huge chains are laid out a long way against the sea bed, but are still no match for the heavy ship drifting. Get a look at the effects this may have on ocean floors and their ecosystems at Real Clear Science.(Image credit: Bahnfrend) #marineecosystem #ocean #oceanfloor #anchor

AI Spots Shipwrecks From the Ocean's Surface and the Air with 92% AccuracyFinding shipwrecks may sound like stuff of movies, but it's an important part of naval research by the Navy. They're interested in finding shipwrecks that may help shed light on human history, including trade, migration and war.Unlike the movies, finding shipwrecks usually don't involve a map with a bloody X marking the location of the bounty - but science has the next best thing: sonar and lidar imageries of the seafloor.Leila Character of The University of Texas at Austin and colleagues, in collaboration with the United States Navy's Underwater Archaeology Branch, has used a machine learning artificial intelligence to spot shipwrecks off the coast of mainland USA and Puerto Rico.Character wrote in The Conversation:The first step in creating the shipwreck model was to teach the computer what a shipwreck looks like. It was also important to teach the computer how to tell the difference between wrecks and the topography of the seafloor. To do this, I needed lots of examples of shipwrecks. I also needed to teach the model what the natural ocean floor looks like.Conveniently, the National Oceanic and Atmospheric Administration keeps a public database of shipwrecks. It also has a large public database of different types of imagery collected from around the world, including sonar and lidar imagery of the seafloor. The imagery I used extends to a little over 14 miles (23 kilometers) from the coast and to a depth of 279 feet (85 meters). This imagery contains huge areas with no shipwrecks, as well as the occasional shipwreck.Character's computer model has an accuracy of 92% and she now hopes to extend the model to spot shipwrecks from around the world.#shipwreck #sonar #lidar #seabed #oceanfloor #archaeology #underwaterarchaeology #USNavy #artificialintelligence #AI #machinelearningImage: Shipwrecks off the coast of Washington at the depth of 25m. Character L, et al. (2021) Remote Sens. 13(9) 1759.