R/V Oceanus: Unalaska 6/29 – 7/1
We arrived on our 6th and final island sometime in the early morning on Wednesday June 29th. It’s hard to believe that we’ve been living and working on the r/v Oceanus for almost two weeks now. We’ve battled rough seas, challenging dive conditions, and long hours in the field and in the lab. Although the weather only cooperated part of the time, we sampled more islands than we had originally proposed to do this year, so I think that alone makes this first expedition a success.
By the time we went to deploy our chambers in the calm, shallow reefs of Unalaska, we had the process down pat. Without ripping currents, breaking waves and strong winds, our only challenge was dealing with the thick understory algae. But by now that was no issue. Setting up the chambers, and then later breaking them down, went on without a hitch.
At this point you may be wondering about the design and construction of these chambers, and what exactly makes them so cumbersome. In the months leading up to this trip the Edwards’ lab has been cutting, stitching and gluing PVC together, along with large sheets of plastic, to make our pyramidal tents. The ocean is a mischievous mistress, and speaking from experience we knew that our chambers had to be sturdy enough to deal with anything the ocean could throw at us (case and point, Atka). However, not only did our chambers have to be sturdy, they also had to be transportable. Well, as transportable as possible that is. We tried to reduce the amount of swimming we had to do by dropping anchor on or near our intended dive sites, but that doesn’t mean we didn’t each, at some point or another, have to schlep a chamber some meters here or there.
Ok so, we have chambers that are sturdy and transportable. Great. To stow them topside, such as on the deck of the Oceanus, we would fold them on themselves to make a 2-demensional triangle. We would transport them to the dive sites like this, and then once anchored lower them into the water. To deploy them, we would swim the triangle to an intended site, and then begin the process of unfurling them. Easier said than done; water is significantly more viscous than air, which means there is a lot more drag working against us. Once the triangle is unfolded, we would use a specially cut PVC sleeve to secure two of the ends together and voila, we have ourselves a pyramid. But our pyramid also has a lot of drag, and anything not secured to the substrate will eventually be moved by any number of processes in the ocean. To counter this, we lay two lengths of chain around the chamber’s skirt. We riveted loops to the chamber’s skirt to better hold the chain in place; trying to manipulate the chain, skirt and loops while wearing thick gloves is also easier said than done. Before the chain is applied we make sure our sensor arrays are appropriately arranged inside of the tent; after it’s all said and done we have a nice microcosm experiment set up in situ in a kelp forest/urchin barren/transition zone.
Chamber retrieval is basically just the opposite process, which can be a little more tiresome than set up. But if my calculations are correct, across six islands we deployed, and retrieved, our chambers 90 times. At this point I think that makes us chamber professionals. It wasn’t always easy, but the data we gathered will definitely be worth our efforts.
Stay tuned for the results!
Pike Spector is currently a Research Operations Specialist with Channel Islands National Marine Sanctuary