Dropstone Island

It started in the red salon.

This room, located right next to the galley on Polarstern's C-deck, is entirely clad in red - red carpets, red upholstery. It's our communal living room, and a lot of good conversations start here.

Today, Melanie wanted to talk about dropstones. Some of you may remember that I studied dropstone communities in the HAUSGARTEN as the cornerstone of my PhD. I compared patterns in the sponges, anemones, and other hard-bottom fauna to classical ecological theories of island biogeography. The stones themselves originate on land and are carried out to sea by icebergs that eventually melt and drop them. They're incredibly common in glaciated regions of the Arctic and Antarctic. More importantly, they constitute the only viable habitats for a number of hard-bottom organisms.

Melanie had the impression that the number of dropstones on the east Greenland continental margin was increasing. A lot of the stones were uninhabited, she said, which suggests they had just arrived on the seafloor. My interest was certainly piqued. Then she shared that the helicopter pilots had observed some pre-dropped dropstones just the day before, on an ice floe not far from the ship. I was sold.

It took a few hours to put the plan together, but soon I was climbing into a helicopter with Melanie and heading out to what we have dubbed Dropstone Island. Friends, I have conducted research in the Arctic for 10 years now and made so many trips up here that I've stopped counting. And this is the craziest thing I've ever seen.

Dropstone Island, seen from the helicopter. 
Photo by Mario Hoppmann.

It looked like an island. Big black patches in the middle of the pure white snow. Mounds taller than me. Dark, layered rock – shale, I think – and sparkling, orange-white quartz. A stone the size of a coffee table. Knee-deep snow, hip-deep if you're not watching. Polar bear tracks, not fresh (thank God). What. Is. This. Place.

We set to work as soon as the gear was unloaded. I placed my ruler on the ground for a size scale and started photographing rocks like mad. Alberto slung the rifle over his shoulder and climbed the highest ridge for polar bear watch. Melanie collected snow samples. Mario took an ice core.

We got everything we needed in just a few hours, but even after all those samples, I still have more questions than answers. How did the rocks get all stacked up like that? They're too big to have been lifted up by anchor ice, and the floe looks too flat to have broken off of a glacier. Is this normal? The ship's crew claim they've seen similar structures in this region before. Did the rocks come from Greenland, or somewhere else? I grabbed a few to show my best friend, a geologist, in the hopes she can identify them.

Dropstone Island. I'm the one photographing rocks. Photo by Mario Hoppmann.

The adventure of Dropstone Island was one thing (not gonna lie, it was totally awesome), but what's more exciting to me is what all of this means. Melanie's impressions may be quantifiably accurate. Maybe there are more and more stones breaking off from Greenland and being carried out to the deep sea. If that's true, it creates a demonstrable link between potentially climate-driven glacial melt and deep-sea biodiversity. More rocks mean more habitat heterogeneity, which means more sponges and anemones but also shifts in the communities of worms and crustaceans that live in the sediments. What starts on land affects the deep sea - it's all linked together.

Some of the rocks on the ice floe. The scale bar is 20 cm, so 
that largest rock is the of an ottoman.

It was pretty fitting that this year's seafloor camera transect at the east Greenland station came the evening right after our helicopter flight. I sat with Melanie for part of it and have to admit I agree with her – there were an awful lot of uninhabited rocks down there, and they look darn similar to what we saw on Dropstone Island. We have a lot of work to do before we can tie the story together, but now we're working on processing the data so we can package the discovery in a publication. I'm really glad we found Dropstone Island.