Scientific Ocean Drilling

The African savanna is one of the most recognizable landscapes on the planet: open grass, a few flat-topped trees, herds of wild animals moving through it. The date usually attached to its start is around 10 million years ago, when grasses running on a drought-hardy kind of photosynthesis spread through the tropics. But the ground was already open long before those grasses arrived.

Over the past 230,000 years, the growth and retreat of the Icelandic ice sheet have led to major changes in the seawater chemistry of the North Atlantic, caused by the interaction between volcanism and ice in Iceland. Scientists at the Institute of Environmental Physics at Heidelberg University have demonstrated this using sediment cores from the northeastern Atlantic – the Rockall Plateau.

A borehole drilled 4,160 ft. into the Atlantic seafloor has uncovered deep, rock-altered water that may help feed the Lost City hydrothermal field.

In late June, a ship with an unusual legacy sailed with little ceremony into a Turkish shipbreaking yard. It was four years early. I stumbled across the announcement on Facebook. As I started trawling the quickly accumulating comments, I watched a small archive of human stories from almost five decades of ocean science unfurl. Two years ago, I was on this ship. Bounding up and down staircases ferrying sediments and samples between labs. Playing table tennis slightly sideways and running laps around the helipad in a mad effort to stay sane under the perpetual Arctic sun.

Healthy oceans support economic stability, coastal communities, food security, and sustainable management of marine resources. Yet one of Earth’s largest and least understood ecosystems lies hidden beneath the sea floor, where microorganisms survive under extreme conditions of limited energy, high pressure, and scarce nutrients.

For decades, scientists have asserted that the leakage of warm, salty Indian Ocean water south of South Africa into the Atlantic is a major contribution to the Atlantic Meridional Overturning Circulation (AMOC), a component of the global ocean conveyor system. New research led by an international team from the Netherlands, USA, China and UK suggests that the mechanism linking leakage of Indian Ocean water and deep-water formation was and is not as straightforward as previously thought.