Wet run

Friends, in addition to leading the Geodynamics students around Patagonia, I have my own personal mission: I am collecting samples. (Of course I am. Are you really surprised? Have you ever known me to travel and just enjoy? Come on.) The samples I'm collecting are part of a project on icebergs that actually served as the impetus for this year's Geodynamics class focusing on the Southern Ocean and coming to Patagonia. The icebergs project came first, and the class took shape around it. 

On the dock outside Puerto Natales where I collected my 
first samples - it was a successful afternoon!

The icebergs project is an effort to understand how ice impacts the marine ecosystem. As many of you know, I have studied the dynamics of dropstone communities in the Arctic since my PhD. Dropstones are terrestrial stones that become entrained glaciers, are carried out to sea by icebergs that calve off of those glaciers, and then fall to the seafloor when the icebergs melt. I have studied how communities form on dropstones through recruitment. I have studied how animals disperse to dropstones as larvae. I was even part of the team that discovered a ginormous iceberg loaded with dropstones (before they dropped) offshore of Greenland.  

But dropstones aren't the only impact that icebergs have on the ocean. Icebergs serve as hotspots of biodiversity all by themselves - stones or not. Glacial ice can be rich in iron, which fertilizes the ocean and increases primary production. There are specialized species of zooplankton that live near ice and munch on the blooming algae. Where there are zooplankton, there will likely be higher predators, too - fish, seals, and whales. A whole ecosystem can form around an iceberg, but we don't fully understand why or how or even who shows up. That's where my research comes in. 

For this project, I'm using a method that my lab has used once before: environmental DNA (eDNA). By collecting DNA out of the water, we can tell which animals are present without having to collect them, observe them, or interact with them directly. eDNA is a great option for non-invasive research, and it's a powerful way to sample a broad range of taxa, from microbes to mammals. You can't catch a whale in a net, but you can tell a whale has been around recently if you find its DNA. 

I'm relatively new to eDNA, and the sampling system I'm using for this project was completely new to me. Granted, it's a pretty idiot-proof system that I got from an eDNA expert at WHOI, but I still wanted to collect the first few samples on my own - no students need observe my struggle. 

I drove to a pier just outside of Puerto Natales, wheeled my "science box" with all the supplies down to the end, knelt on the boards, and lowered a bucket into the water. Yes, I literally sampled with a bucket, because all I needed was surface water. Once I had a full bucket of water, I filtered it with the idiot-proof pump system and saved the self-preserving filters in a sterile bag. I knew the system was easy to use, but I still breathed a sigh of relief when the first samples went perfectly. In just an hour, I had our first three replicates in the bag - literally. 

Filtering water on a dock in a Patagonian fjord? Not a bad day. 

Such a rough life...my office for the day.