The anatomy of an Antarctic scientific dive

When we (very eagerly) share that we dive underwater for science, the first questions to pop up are usually: How much time can you spend down there? What are you finding? And while our sampling methods definitely deserve another blog post, here is the anatomy of a typical dive for science sample collection.

Photo by Jacob Wynne. Paola swimming with her collection mesh bag at the Pierce's Casing dive site.

Our typical antarctic dive sits at around 45 mins to an hour, and while a lot of factors play in this, we are usually limited by how deep we are, our air consumption, tasks at hand, and not surprising to anyone, how cold it is (taking notes underwater with very cold hands is not fun). Our dive plans are designed around the science tasks, from grabbing mud 10cm deep into the seafloor, to collecting sea stars and urchins that will tell us more about the diet across different habitats.

A typical dive includes a mix of these tasks, usually divided into two dive buddy teams. Before going underwater, everyone has already clipped their science instruments down a vertical underwater rope with multiple lights and hooks we call the DownLine.

Glimpse of the flagged downline beneath the dive hole.

Now the fun part!

Dive starts, and a coordinated dance underwater of science collection plays out. At the Jetty 60ft deep, a dive team goes to collect animals into the yellow mesh bag (picture above), and the second team goes to grab sediment nearby to study the microbes later in the lab.

And just like that, ~40 minutes of the dive go by! If time allows, another important task emerges: documenting the science. Either for scientific record, data or equally important, science communication and outreach, the team clips the science instruments in the DownLine and switch to their amazing underwater camera systems to document the dive.

Above the water

Photo courtesy of Nikolai Marquardt.

Science does not stop once we get out of the water. Once out, we pull the DownLine up to bring into the world the samples and critters. Coolers filled with local seawater wait near the dive hole to hold our newly collected samples. Water taken from below the sediment is immediately processed into an array of plastic vials to analyze for nutrients, ions, dissolved inorganic carbon among other things. Mud is also sliced by how deep into the seafloor it is and maintained cold afterwards. The critters on the other hand, stay nice and cold in the cooler while they take a roadtrip down to the Crary Lab Aquarium!

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Photos courtesy of Nikolai Marquardt.