Two brown seaweeds with smaller, red seaweeds on the side. Photo by B.J. Baker.I’ve been spending my last posts talking about diving and am still are not quite yet done with the topic. But I thought that this time I’d talk a bit about what we see on those dives. I might just as well start with what we see most, which are macroalgae (or "seaweeds", which means pretty much the same thing as "macroalgae").

A couple of weeks ago, we were able to start our main experiment for this field season that took nearly two months to set up. While this was a super exciting accomplishment, our team’s work is far from over. There are certain tasks (like titrations, spec work, and molt collecting, oh my!) that need to be completed daily. These tasks not only help ensure that our pH treatments are correctly set, but also allow us to collect some of our data throughout the experiment. Today, I am going to walk you through a typical workday for experiment maintenance.

In my previous All Creatures entry I introduced you to two local stars – seastars that is-  in the waters around Palmer Station.   As members of the phylum Echinodermata, sea stars have a large and diverse extended family, as the opening image reflects. 

A five-armed purple sea star rests along a similarly colored short spined urchin partially covered in algae; below the pair stretching across the image a brownish sea cucumber and below a longer, less densely spined pencil urchin

water samplingIf you’ve read Addie’s latest post, then you know that the experiment is now officially underway! Read on to find out more about the water chemistry we do each day and why.

white bucket of seawater with green and red plants with the white tubular mixing tankNow that we have the experiment started, as Hannah discusses in her most recent post, we’re done sorting amphipods and have moved onto doing seawater chemistry. Every morning we test six water samples from randomly selected buckets to give us more precise measures of the conditions than a pH probe by itself can provide. Each of us has our own job that we take care of, which for me is running titrations to calculate the alkalinity of the water (a measure of the sample’s ability to buffer added acids and resist changes to pH). Meanwhile, Jami is running the spectrophotometer to determine pH, and Hannah is measuring the pH of all 24 tanks with the handheld probe to make sure the ones we aren’t testing that day are still at the right level.