Well, I have been out for the last couple days! On Saturday I got the go ahead from Keith to gear up and head out to dive. Yay! It was so exciting to go back out and explore more of the island. I went out with Jessica, one of the MCR lab techs who is also finishing up her Master’s degree, and another undergraduate, Erin, who is the undergraduate assistant for Keith and Jessica. Over the summer Keith and Jessica work with the physical oceanography instruments and are responsible for the majority of the instrumentation deployment, retrieval, data download, and reprogramming. Underwater instruments are a vital component to long term studies because they’re able to take continuous measurements on basic water parameters. Most of these instruments get deployed for six months at a time and can take measurements every 30 seconds! These include thermostores, which measure water temperature, CTD’s (conductivity, temperature and depth) profilers, ADCP’s (acoustic doppler current profilers), which measure current velocity and work similar to a sonar by using sound waves, and SeaFETS, which measure pH. Having such long deployments and taking continuous measurements provides an incredible amount of baseline data which can then be used by researchers to put their experimental field data into a context of the physical environmental conditions. So anyway, once I got the OK, we geared up and headed to the lagoon, sometimes called the back reef, in order to do maintenance on some of our long term fish transects and also to retrieve a thermostore which had been deployed last year. To retrieve the thermostore, all we had to go off of was that the instrument was inshore of one of the transects – we didn’t know where or how far, so we were basically told to spread out and search. Although the depth reaches a max around 8 or 9 feet, there’s still a whole lot of stuff going on underwater, and it’s absolutely gorgeous! It was my first time in the lagoon, and I couldn’t get over how beautiful the turquoise water looked against the backdrop of those Moorea mountains. On the way out to the site, I couldn’t stop myself from snapping photo after photo…
Ahh so gorgeous!
The really light colors you see when looking at a lagoon are caused by the incredibly shallow depth of the water. The lagoons we were in were no more than 10 feet deep, and most of the time we were as shallow as 5 or 6 feet. Most dive computer pressure transducers don’t even begin to record dives until the pressure gets below 5-7 feet, so we have to keep track on our own watches to see how long we’ve been underwater.
My goal is to get a good above water and below water shot! This is the best I’ve gotten so far (out of lots of pictures), but I’m just going to keep trying.
So after quite a while of swimming and searching and scanning the reef for a tiny instrument that’s about a foot long and placed on a bommie (a giant coral structure that has been built up over the years by mounding corals and other coral skeletons), we found it! I snapped some pictures of Jessica retrieving the old instrument and then a picture of what it looks like after. Woohoo scuba diving scientists at work!
Then, lots of swimming and cleaning and scrubbing of yellow tubing that mark every 5m of our permanent transect. Each transect runs 50m in total, and each site has at least 4 transects. So there’s lots of swimming! Part of transect maintenance is not only cleaning and/or replacing the yellow tubing so that it’s clearly visible for the divers who will survey the transect in the coming weeks, but also finding the damn markers. Turbinaria ornata is the prominent macroalgae that grows in Moorea. One of the graduate students in the MCR is pursuing her Ph.D. studying the dynamics and structure of Turbinaria communities in relation to corals, in order to understand what factors are may be important in determining community composition. Turbinaria is stalk shaped and attached to hard substrates. Coincidentally, our tubing is stalk shaped and placed on hard substrates. So when I’m scanning the water looking for a marker, I notice that EVERYTHING looks like the marker, which is often covered in algae! So there’s a lot of swimming, a lot of searching, and a lot of scrubbing. Mmm the glamorous life of a marine biologist.
See the turbinaria? It’s the brown stalk-like things growing off the coral mounds.
So we proceeded to clean and do maintenance on fish transects for the next couple days. So far I’ve gotten to see LTER sites 1 and 2 in the lagoon and fringing reef. There are six LTER sites around the island, each with a site for the fringing reef, lagoon, and fore reef. Ideally I may be able to see them all this summer! But it just depends on what my advisors are doing and where they need to go.
The other day, I was underwater in the lagoon for nearly 5 hours. The whole time I was doing work, so it didn’t feel like too long. But wow is that a long time to be underwater! Just as we finished the last dive, we got on the boat and caught the sun just as it was slowly making its way back down along the horizon.
So many beautiful sights to be seen…
Well I have a lot more pictures and stories to catch up on. But taoto maitai (goodnight) for now!