My name is Umi Hoshijima. I am a grad student at the University of California, Santa Barbara. And I’m here to work with pteropods.

Also known as sea snails, pteropods are sensitive to acidifying oceans.

The pH of the water can really impact the ability of calcifying organisms to make their shells. As the pH decreases, the amount of carbonate in the water also decreases and carbonate is one of the building blocks of a lot of the shells that are in marine organisms. For example all of the mollusks, the snails, the sea urchins, all of these use calcium carbonate to make their shells.

Umi is part of a team monitoring the changing pH levels around McMurdo Sound.

We have an instrument down there called a Seafet that we use to monitor the pH of the ocean. And the pH is really important in sea water because it’s really closely tied with the carbon dioxide. And as we see more carbon dioxide emissions, we’re seeing more acidic waters. And we’re trying to get an idea of what the pH does here naturally in order to project what the future might hold for a lot of these animals. By collecting a water sample right next to the sensor, when the sensor is logging, we’re able to verify and calibrate the sensor over the whole year that it is being deployed here.

Over the course of a year, the ocean’s pH changes dramatically.

In a lot of way were interested in what the water conditions do to the organisms, but in a lot of ways the organisms also influence the pH of the water as well. What’s really cool is back in California I work in the kelp forests and we see a really big daily signature of pH where it cycles up during the day when there’s a lot of photosynthesis and you take up the carbon dioxide so the water is less acidic. And then at night, everything is breathing so everything becomes more acidic and the pH goes down. Here you don’t really have a daily cycle of light and dark, and so you actually see a similar signature over the whole year. It’s sort of like one long day right now, and one long night in the winter.

Umi and his team are deploying sensors throughout the region.

We’re trying to maintain long term sites at the jetty, and also at Cape Evans. We were able to pull those sensors out, deploy new ones and also put in a new sensor at New Harbor across the Sound for this next winter. And we’re hoping that these three sensors will record through the winter and continue to give us a better idea of the characterization of the sea water here.

The data collected over the last year offered the most complete profile of the ocean’s annual changes.

We were able to retrieve those two sensors that we were able to put out last year and it seems as though they had recorded throughout the duration of the winter. So, we have a full 365 day picture of what’s going on right here. So that data has yet to be analyzed but I’m looking forward to digging into it when we get home.