Shipwreck day

"In the early part of the 20^th century, the United States and Japan engaged in a federally-funded, large-scale joint effort to create artificial habitats across much of the tropical Pacific Ocean. This ecological experiment is most commonly referred to as World War II."

I once started a proposal with those words. My maritime archaeologist collaborator vetoed it. 

Corals on the port side hull of one of our wrecks

Here's the thing, though: WWII shipwrecks do constitute a massive ecological experiment. By the end of 1945, the U.S. and Japan had each sunk thousands of ships and airplanes on the seafloor. They're all primarily composed of metal, vary in size and structure, and were sunk within a few years of each other. Most are located in shallow lagoons or nearshore habitats surrounded by coral reefs. They actually serve as the ideal natural experiment for studying biodiversity on anthropogenic habitats.

I love shipwrecks. You know this, friends. So when my research team made enough progress that we could afford to dedicate a day to a side project, guess where my brain went: shipwrecks. Show me all of the shipwrecks. 

Large Porites lobata corals (that's our study species!) on 
the upper surface of one of the shipwrecks. 

We ended up choosing two shipwrecks to study in Palau. Both of them are at the same depths as our other study sites, made of metal, and surrounded by corals. I thought they presented an excellent way to answer two major questions: (1) How does the structure of a shipwreck influence the community that lives on it? (2) How does the community living on a shipwreck compare to the surrounding habitats? 

We collected our data with cameras. I know that's a (sarcastic) big surprise, since about 80% of what I do is image analysis. You can learn a lot from a photo! I wanted to collect photos of the large adult corals and the little baby corals living on the shipwreck and the surrounding reef, so we decided to divide and conquer. It actually took a lot of concentration to swim in transects along the side of the wreck and make mental notes of my location. I couldn't just swim in random directions and photograph whatever interested me - I had to be consistent, and I had to remember what I did. After the dive, we spent a few minutes writing down in the team's field notebook where each person had swum so we could reconstruct the locations of each photo later. I even assigned Maikani to swim at the surface and draw the site, including as many details as she could. We need to remember where we went and what we saw with absolute precision. 

I am so excited that we were able to collect image data from the two shipwreck sites, and I look forward to identifying all of the species back at home! It was an excellent day.