Discovering the hidden secrets beneath the Antarctic ocean

It almost didn't happen, but our recent expedition to survey the Antarctic ocean floor revealed untold wonders. We discovered that the seabed is carpeted with incredible life, reinforcing the need to protect this remote stretch of ocean as soon as possible.


In hindsight, it was kind of a wild idea.

In the middle of a pandemic, individuals from across the Greenpeace network set out to bring people from 21 countries and seven organisations to one of the southernmost cities in South America, along with a Greenpeace ship and a Canadian submarine, to sail to the Antarctic to survey seafloor habitats.

The ship carrying the sub was delayed. Several of us, including the sub pilot (me), tested positive for Covid while quarantining before boarding. The weather looked bad, our window was shrinking, and there were nervous discussions about how much time we could lose without the whole thing falling apart.

But the stakes were pretty high.

The UN is negotiating a Global Ocean Treaty, and if they get it right it will enable us to scale up ocean sanctuaries for the first time. That’s a big deal, as sanctuaries are the best tool we have to protect biodiversity, rebuild depleted populations, and give our oceans a fighting chance to survive the impacts of industrial fishing, plastic pollution, and climate change.

Yellow sponges, red coral and other marine life clustered together on the seabed

Treasures on the seabed: coral and sponges cluster together beaneath the waters of Active Sound in the Antarctic. © Greenpeace

Meanwhile, the Antarctic ocean commission, which is responsible for protecting Antarctic marine life, is meeting later this year to consider proposals to create two new massive sanctuaries, either of which would be bigger than anything in place today.

So our team was united in our belief that we had to go ahead.

It’s hard enough to pull off successful submarine dives in places where we don’t have to deal with freezing temperatures and constantly changing ice conditions. But for Antarctica we expected to lose at least a third of our potential dives to weather and equipment issues. Instead, miraculously, we were able to dive every day.

However, after a successful test dive to 465m near Half Moon Island near the Antarctic Peninsular, we completed 12 research dives in 10 days.

The diversity and abundance of marine life we encountered was astounding. The slopes, canyons and walls we surveyed were frequently covered with brightly-coloured corals, sponges, hydroids, feather stars, bryozoans, sea squirts, and countless other animals. At least 10 of the dive sites are strong candidates to be designated as vulnerable marine ecosystems, which will bring them immediate protection from fishing.

Seen from the sub


Just 0.5mm long, bryzoans have a crown of tentacles for filter feeding and create colonies in the shape of fans, sheets and bushes.


Another tiny creature, hydroids have different life cycle stages – a kind of free-floating jellyfish and larger colonies on the seabed.

Sea squirts

As their name suggests, sea squirts have two holes – one for sucking in water, and another for pushing it out.

We pressed on, deep into the Weddell Sea which is typically covered with sea ice. Other recent attempts to work here were stymied by heavy ice conditions, but this time we found an open path south. We conducted research dives that we believe were the furthest south ever made.

It was incredible to explore such a remote wilderness, but shocking to see how quickly climate change is transforming the region. In places that are nearly always covered by ice, at depths that have never seen the light of the sun, we found rich, thriving invertebrate communities that surprised us all with their bright orange, red, and yellow colours.

The views from the deck of the ship were as astounding as those from the submarine.

Humpback whales were constant companions, gorging on krill before heading north to breed. Orcas harassed the whales and fed on fur seals. Albatrosses, skuas, cormorants and petrels were among the many seabirds we encountered.

Penguins were my favourite, fast and sleek in the water and cartoonishly goofy on land or icebergs. The backdrop for all of this included sheer black cliffs, snow-covered mountains, frozen waterfalls, and a parade of icebergs of stunning shapes and hues.

I’m glad we refused to give up on this expedition. The images, data, and stories from our work here will jumpstart efforts to build support for ocean sanctuaries. These are uncertain times, but it’s clear that international cooperation in support of a green and peaceful planet is more important than ever. Continuing on our current path – to catching the last fish, or drilling the last oil deposit – is the truly bizarre idea.

Together, we can build a movement centered in environmental and social justice that can steer us on a wiser course.

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