Audrey Djunaedi

Day 5

Thursday, September 15, 2011

Everyone was excited for today's ROPOS dive. We followed the edge of the recent flow at Axial Seamount for a while, seeing the new black lava stand out against the older flows beneath it. The first time we tried to sample the flow, the glassy basalt broke in ROPOS' grip. The second time, a crowbar was used to pry off one of the spheres protruding from the seafloor, and I watched as Keith Shepherd used a gentle but firm grip to lift the piece off the ground and into the 'bio box,' where most of the samples were kept before being brought to the surface. Later, students and researchers filled the ROPOS control room when we encountered a snowblower, which looked like a cave frosted around its mouth with white, snow scattered around the ground around it (the "snow" here was bacteria).

The care and feeding of Seaflow

Thursday, September 15, 2011

For the past week or so, I have been caring for a flowthrough cytometer installed on the Thompson. This device continuously processes a stream of seawater brought in through the Thompson's seawater intake and sucked into the machine through a thin blue line. Seaflow is a new twist on traditional flow cytometry. Cytometers were initially used to analyze cells for diagnoses (ex. blood cancer) in the medical field. Instead of analyzing individual samples one by one, though, Seaflow has been modified to deal with the difficulties of examining running seawater containing phytoplankton. Phytoplankton are photosythesizing organisms that "can't fight the current" - Planktos means "drifter" in Greek. They form the base of many marine food webs and influence global climate, in addition to many other important reasons we study them. Seaflow will allow us to obtain continuous realtime data on these organisms, contributing to the goals of the Ocean Observatories Initiative ( After the cytometer gets going, it is almost completely autonomous.

So far, my latest challenge with Seaflow has been cleaing out a film of brown algae and debris that clogs the intake line whenever the machine has not been used for a while. From biofilms in the Seaflow lines, to juvenile barnacles trying to settle on the Slocum glider and limpets crawling onto the sensor bots, biofouling is an ever-present challenge in the field of ocean engineering. Eventually, though, Seaflow will require minimal onboard maintenance since some of its functions can be controlled over the ships' satellite connections. Even now, Jarred, Seaflow's creator and engineer, has been able to tinker with the cytometer from land, emailing me instructions whenever he needs something more done. Check out Seaflow's web page for more information! Here's a YouTube video of the kind of data we'll be collecting:

Day 2,3 part II

Saturday, September 10, 2011

Of all the interesting cases of equipment brought onto the ship, the box containing ornament-like sensor bots was one of the most exciting to explore. Housed in a clear polycarbonate sphere sealed together with a vacuum pressure process, each sensor contained only one battery to power a remarkable suite of oxygen, pH, and temperature sensors. Unique sensing films on the surfaces of the balls (visible in the picture as translucent thumbnail-sized circles) changed the way they interacted with light in reaction to environmental water quality. Intense flashes of blue light appeared regularly near Dr. Cody Youngbull's work station, where he tested each sphere before we mounted them in protective containers for deployment. The bots communicate scientific data through these patterns of flashes. A high-speed camera records the sequences for analysis onboard the ship. It is amazing that these tiny spheres are sealed with a single O-ring, and that they can withstand the pressure at a couple thousand meters of depth! Since they are positively buoyant and easily attachable, the spheres can be mounted in a variety of the end of a string, suspended vertically throughout the water column, deployed as an array of sensors throughout the OOI network...the possibilities for the use of these instruments in remote sensing are fairly impressive (and we haven't even explored the option of biodegradable instruments yet!).

It takes the work of a few students, Cody, and James to put the sensor bots together, test them, and place them on the stand that they'll be deployed on. The Captain of the ship even stops by to offer suggestions. It's interesting to see how much work goes into the design of the spheres, in additional to pre-deployment planning. The stand is made with large bungee cord loops so that ROPOS can work easily to uncover the spheres once the stand is in the water, and the weight of the whole structure ensures that it will stay upright even on uneven slopes (i.e. basalt in its many forms). It will be interesting to see how the system works once it is at the bottom of the ocean.

Day 2,3

Tuesday, August 23, 2011

During our first science meeting, we learn about the process of planning and conducting a scientific research cruise. The chief scientists also brief us on existing information about Axial Seamount. It is exciting to hear about current knowledge of this area, especially concerning the recent eruption in April. Much of this information has not been published, and we will have the unique opportunity to learn from experienced mentors who are engaged in exploring the changes that have occurred at this site.

Reevaluating my zooplankton project
With the goals of our scientific mission in mind, I end up modifying my initial project plans. One of the difficulties in choosing a topic is finding a question that you can answer with the time and resources you are given. Although zooplankton are ecologically important as food for many fish, birds and marine mammals, we decide that answering a question about bacterial communities will be more productive. I am excited about working with my mentor Bob Morris to explore research questions about bacteria near the vent sites. Furthermore, I may have data from last year to compare to what we collect on this research cruise.