Sitrep: part 2

NOAA divers entering the water at a shipwreck site in Lake Huron.
Photo by Stephanie Gandulla.

It’s a surprisingly satisfying feeling to watch a field team from afar. Every day, the first email I open is the one labeled “sitrep” – short for “situation report.” That’s the one document that tells me how the field team is doing with their sample collection, and it is so exciting to watch them succeed.

Friends, as you know, I’m currently involved in a project that’s testing whether DNA collected from the environment (environmental DNA or eDNA) can be used to locate human remains. eDNA includes everything  – human and non-human sequences alike. We’re not sure if human remains leave a detectable signal in the surrounding water or sediment, so that’s what our study is designed to figure out. My lab is collaborating with the University of Wisconsin Biotechnology Center for the experiment, and we’re funded by the DPAA (Defense POW/MIA Accounting Agency). 

Bridget Ladell (UWBC) and Stephanie Gandulla (TBNMS) on
Lake Huron during testbed operations. Photo by Calvin Mires.

One easy way for the eDNA team to get into the field was to tag along with planned excavations of archaeological sites – some of you might remember we did this in Saipan. But we also wanted to collect samples from an area with colder water, where there are a lot of shipwrecks and the infrastructure to access them, preferably in the United States.

Allow me to introduce you to Thunder Bay National Marine Sanctuary. This area on the eastern coast of Michigan hosts about 100 shipwrecks, all preserved in the ice-cold, unsalted waters of Lake Huron. Some of the shipwrecks in Thunder Bay are associated with loss of human life, so they provided an excellent testbed for our eDNA project.

Over the past two weeks, Thunder Bay divers have collected sediment and water samples from shipwreck sites in the sanctuary. It was challenging diving – 70 m deep, about as cold as freshwater can be without freezing, dark, and silty. I’m a technical SCUBA diver, as many of you know, but the conditions in the Great Lakes were enough to make even me hesitate to jump in the water. Instead, we trusted the operation to the NOAA dive team, and that was definitely the right call. They knew what they were doing and even came up with some innovative ways to improve the sample collection process.

Calvin Mires (WHOI) filtering a water sample in
the lab at TBNMS. Photo by Stephanie Gandulla.

Once the samples came to the surface, it was up to the shore-based team to process and preserve them. Calvin and Bridget used their experience from Saipan to make the workflow as smooth as possible, and I dare say, we’re getting it down! Even though I’m not there in person, it’s very satisfying to see the samplers I designed and tested and the team I trained all working well.

We have one more testbed to go, and then it will be time for data analysis. I’m extremely curious how the results will turn out – whether we’ll have a strong signal of human remains at some sites but not others, or frankly, whether there will be any discernible signal at all. This project is incredibly exploratory – our question is “does this work?” – so failure is always an option.

Whatever happens, I will eagerly await the next “sitrep”!