The daily heartbeat: A vertical migration in darkness

Every evening, just after sunset, the ocean stirs as billions of tiny animals—plankton, squid, lantern fish—begin the greatest synchronised migration on Earth. They rise from the inky depths to feed in the safety of darkness, forming a hidden, shimmering cloud that can stretch across entire basins.

The juvenile squid, approximately 30 centimeters  in length, was filmed on March 9, 2025, at a depth of 600 meters (1,968 feet) near the South Sandwich Islands in the South Atlantic Ocean.

This unprecedented observation was made possible by the remotely operated vehicle (ROV) SuBastian, which is capable of reaching depths up to 4,500 meters. The sighting coincides with the 100th anniversary of the species' formal identification. ​

The expedition was led by the Schmidt Ocean Institute, in partnership with Ocean Census and the University of New Hampshire’s Center for Coastal and Ocean Mapping/Joint Hydrographic Center. The mission focused on exploring and mapping seamounts in international waters, about 900 miles off the coast of Chile.

In a surprising turn of events, scientists have uncovered that deep-sea nodules are significant sources of oxygen. This discovery challenges previous assumptions about the deep ocean's oxygen levels and has profound implications for marine ecosystems.

Researchers have charted a colossal deep-sea coral reef system off the southeastern coast of the United States. Described as an underwater metropolis of a 'million mounds', this vast network stretches across the continental shelf and heralds a new chapter in ocean exploration.

The mapping of this coral reef, a feat accomplished through advanced 3D imaging technology, is a landmark in maritime science, underscoring the vast, uncharted territories that still lie hidden beneath the waves.

Ocean deoxygenation has detrimental repercussions. Fish, crabs and other significant species of marine life that are unable to flee these low oxygen zones may perish as a result. People who depend on them for food and employment may be subsequently impacted by their absence as many of these species are economically significant.

Additionally, there is a negative feedback loop at play: as ocean oxygen levels decline, so does its capacity to absorb carbon dioxide. This may cause global warming to accelerate even further.

A study just published in Nature Communications suggests that the Atlantic Meridional Overturning Circulation (AMOC), of which the Gulf Stream is a part, could be approaching a tipping point. The AMOC, which has been gradually weakening over the last century and is reportedly at its weakest in over a millennium, could shift from its current strong mode to a weak one, with profound implications for the global climate.

Observations using the newly upgraded human-occupied vehicle Alvin are the first of a deep-sea coral reef in the Galápagos Marine Reserve.  The reef, found at 400-600 meters (1,310-1,970 feet) depth at the summit of a previously unmapped seamount in the central part of the archipelago, supports a breathtaking mix of deep marine life, Woods Hole Oceanographic Institution writes.

While on a mission to map the volcanic geography of Cocos (Keeling) Islands Marine Park off Western Australia, researchers aboard the vessel Investigator also surveyed the deep-sea life in the Indian Ocean Territories.

In doing so, they came face-to-face with many fascinating, and some previously unknown, species.

Besides filming videos of the vast marine life amidst the summits of seamounts, the team also collected specimens from depths as deep as five kilometres below the surface.

We have discovered an amazing number of potentially new species living in this remote marine park

Dr Tim O’Hara, Chief Scientist of the expedition and Senior Curator, Marine Inveterbrates at Museums Victoria Research Institute

During the expedition, the researchers had been sharing their discoveries with more than 850 school students and community members in Australia through real-time livestreaming.

The expedition was a collaboration between Museums Victoria Research Institute and CSIRO, in partnership with Bush Blitz, Parks Australia, Australian Museum Research Institute and the Western Australian Museum.

More than 35 potentially new deep-sea species have been discovered at the Clarion-Clipperton Zone (CCZ) in the central Pacific. 

Ranging from starfish and segmented worms to sea cucumbers and various types of coral, these specimens were collected using a remotely operated vehicle.

In total, 55 benthic specimens were collected from seamounts and abyssal plains. Of these, 39 were found to be potentially new to science, with nine that were referable to known species.