Oceans

Humans have sailed the world’s oceans for thousands of years, but they haven’t all reached port. Researchers estimate that there are some three million shipwrecks worldwide, resting in shallow rivers and bays, coastal waters and the deep ocean. Many sank during catastrophes – some during storms or after running aground, others in battle or collisions with other vessels. Shipwrecks like the RMS Titanic, RMS Lusitania and USS Monitor conjure tales of human courage and sacrifice, sunken treasure and unsolved mysteries. But there’s another angle to their stories that doesn’t feature humans. I have studied the biology of shipwrecks in the United States and internationally for 14 years. From this work, I have learned that shipwrecks are not only cultural icons but can also be biological treasures that create habitat for diverse communities of underwater life. The USS Monitor, which sank off Cape Hatteras, North Carolina, in a...

Nine years ago, I stood on the muddy banks of the Great Marsh, a salt marsh an hour north of Boston, and pulled a thumb-sized crab with an absurdly large claw out of a burrow. I was looking at a fiddler crab – a species that wasn’t supposed to be north of Cape Cod, let alone north of Boston. As it turned out, the marsh I was standing in would never be the same. I was witnessing climate change in action. The Great Marsh is on the Gulf of Maine, the piece of the Atlantic that extends approximately from Cape Cod, Massachusetts, to Nova Scotia, Canada. The marshes along the gulf are critical breeding sites for many bird species. But the water there is warming faster than almost anywhere else on the planet. And with warming water comes warm-water species. Marsh grass is essential for both habitat and adapting to sea-level rise in the Great Marsh. David S. Johnson Maryland blue crab and black...

PFAS, the “forever chemicals” that have been raising health concerns across the country, are not just a problem in drinking water. As these chemicals leach out of failing septic systems and landfills and wash off airport runways and farm fields, they can end up in streams that ultimately discharge into ocean ecosystems where fish, dolphins, manatees, sharks and other marine species live. We study the risks from these persistent pollutants in coastal environments as environmental analytical chemists at Florida International University’s Institute of the Environment. Because PFAS can enter the food chain and accumulate in marine plants and animals, including fish that humans eat, the spread of these chemicals has ecological and human health implications. Biscayne Bay and nearby coastal areas are teeming with fish, including many varieties that people eat. NPS image by Shaun Wolfe I...

As oceans waves rise and fall, they apply forces to the sea floor below and generate seismic waves. These seismic waves are so powerful and widespread that they show up as a steady thrum on seismographs, the same instruments used to monitor and study earthquakes. That wave signal has been getting more intense in recent decades, reflecting increasingly stormy seas and higher ocean swell. In a new study in the journal Nature Communications, colleagues and I tracked that increase around the world over the past four decades. These global data, along with other ocean, satellite and regional seismic studies, show a decadeslong increase in wave energy that coincides with increasing storminess attributed to rising global temperatures. What seismology has to do with ocean waves Global seismographic networks are best known for monitoring and studying earthquakes and for allowing scientists to create images of the planet’s deep interior. These highly sensitive instruments continu...

Two miles below the ocean surface off Monterey, California, warm water percolates from the seafloor at the base of an underwater mountain. It’s a magical place, especially if you’re an octopus. In 2018, one of us, Amanda Kahn, was aboard the research vessel E/V Nautilus when scientists discovered the “Octopus Garden.” Thousands of pearl octopuses (Muusoctopus robustus) were curled up into individual balls in lines and clumps. As Nautilus Live streamed the expedition online, the world got to share the excitement of the discovery. We now know why these amazing creatures gather at this and other underwater warm springs. Scientists with the Monterey Bay Aquarium Research Institute take viewers on a journey to Davidson Seamount in a video narrated by Jim Barry, an author of this article. Credit: © MBARI. In a new study involving scientists from several fields, we explain why octopuses migrate to the Octopus Garden....