Tiny but voracious marine organism studied — video

Tiny but all-consuming marine organism focus of UGA Skidaway Institute study

Marc Frischer

Doliolids are tiny marine animals rarely seen by humans outside a research setting, yet they are key players in the marine ecosystem, particularly in the ocean’s highly productive tropical and subtropical continental margins, such as Georgia’s continental shelf. University of Georgia Skidaway Institute of Oceanography scientist Marc Frischer is leading a team of researchers investigating doliolids’ role as a predator in the marine food web.

Doliolids are small, barrel-shaped gelatinous organisms that can grow as large as ten millimeters, or about four tenths of an inch. They are not always present in large numbers, but when they bloom they can restructure the marine food web, consuming virtually all the algae and much of the smaller zooplankton.

A doliolid with a cluster of juvenile doliolids on its tail. Actual size is approximately three millimeters, or one eighth inch.

“The goal of this particular study is to find out what the doliolids are eating quantitatively,” Frischer said. “This is so we can understand where they fit in the food web.”

Scientists know from laboratory experiments what doliolids are capable of eating, but they don’t know what they actually do eat in the wild. They are capable of eating organisms as small as bacteria all the way up to much larger organisms.

“What they are eating and how much are they eating from the smorgasbord that is available to them, that is the question,” Frischer said. “We are investigating how much of those different prey types they are really eating out there across the seasons.”

The project involves intensive field work, including 54 days of ship time on board UGA Skidaway Institute’s Research Vessel Savannah. During the cruises they conduct trawls using special plankton nets to collect the doliolids. They also collect water samples to understand the conditions where the doliolids thrive.

Graduate students Lauren Lamboley and Nick Castellane deploy a plankton net from the Research Vessel Savannah.

“We take the doliolids and the water samples back to the laboratory, and that is where the magic begins,” Tina Walters, Frischer’s laboratory manager said.

Because the animals are gelatinous and very delicate, the researchers cannot use classical microscopic techniques to dissect the animals and analyze their gut content. Instead they extract DNA from the animals’ gut and use sequence-based information to determine what the doliolid ate.

“We go through a process called quantitative PCR,” Walters said. “So even though we can’t see the prey in a doliolid’s gut, because the prey have unique DNA sequences, we can identify and quantify them using a molecular approach.”

The three-year project is funded by a $725,000 grant from the National Science Foundation and will run until February 2018. Frischer’s collaborator on the project is Deidre Gibson from Hampton University. Gibson received her Ph.D. from the University of Georgia in 2000, and did much of her graduate research at Skidaway Institute with Professor Gustav Paffenhöfer.  In addition to Walters, Savannah State University graduate student Lauren Lamboley is part of the team, along with a number of students at Hampton University. Several undergraduate research interns have also participated in the project, gaining hands-on research experience. Frischer is also working with the Institute for Interdisciplinary STEM Education at Georgia Southern University to engage K-12 teachers by inviting them to participate in the research cruises.

Congratulations…

… to Skidaway Institute tech Tina Waters! She won a student poster award at the ASLO meeting held in New Orleans last month. The title of her winning poster is:

MOLECULAR PROFILING OF ZOOPLANKTON GUT CONTENT USING PNA-PCR AND DENATURING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (PNA-PCR-DHPLC)

LaGina M. Frazier, Gustav-A. Paffenhöfer, and Marc E. Frischer all collaborated with Tina and were cited on the poster. In addition to being a valued member of the Skidaway Institute science team, Tina is a grad student at Savannah State.

Friday April 29, 2011 – Moving Ice Camp

Today was another lab day, and although our special pipettes still hadn’t arrived we felt we had to go ahead and process our RNA samples.  During our first trip to Barrow last spring we had experimented with holding these samples until we got home before processing them. The results were not good, and so we decided that we had to process the samples as soon as possible after they were collected. We felt it was risky to even holding the samples a single extra day so we moved ahead using our back-up pipettes. But can you believe?! Exactly as Zac was finishing-up with the extractions the pipettes were delivered. The only saving grace was that both Zac and I had both missed lunch and when we unpacked the box and found the Twizzlers and peanut m&m’s that Victoria had used as packing material we were thrilled.  Thanks Vic!

While Zac was hard at work in the lab purifying RNA, I spent the morning and most of the afternoon out on the ice helping to move our ice camp. During our last trip in January we were unable to reach our primary sampling site about 1.5 miles offshore due to ice conditions and the lack of a suitable ice trail, so we had to settle for a location closer in. The water there was quite a bit shallower. Although all our measurements indicated that we still were in oceanic and well-mixed water, we can’t be certain that we can directly compare the data from that site to all the rest of the data that we are generating. So during the planning for the current trip we had decided that if we managed to get two samples from our primary site and we still had time during this trip, that we would move our camp and sample from the more inshore location.

Sampling both locations at essentially the same time will allow us to directly compare results from both the near shore and offshore locations. We’re hoping they are similar!

All has gone well, so today we began to implement our decision and moved our ice camp inshore.  With Rachel Siple, myself, and the UMIAQ crew, we headed out on the ice. Reaching our destination we drilled an exploratory hole in the ice and measured the water depth and ice thickness. We’re really looking for 10 meters of water, but our minimum is 8.  Unfortunately at the first hole we drilled we only had 7M of water so we were a bit disappointed.  From experience we knew that the bathymetry in this area is highly variable so we moved about 30 meters from the first hole and drilled another.  At this location we measured the water depth to be a little over 8 meters. Although marginal, it met our criteria.  We are still hoping to find a better site. We got back on our snow machines and moved to the other side of a very large ice ridge and drilled a third exploratory hole. Alas, the depth was even less there so we decided to go ahead and set-up camp at the second place we looked.

Setting up an ice camp.

Setting-up camp involves removing the snow from the area (lots of shoveling); positioning holes for the pump inlet and outlet (for the big tent) and a large hole to accommodate the Niskin bottle in the small tent; and documenting water depth, ice thickness, water temperature, salinity, and light attenuation.  It’s especially important that we know light attenuation since we need this information in order to set-up our incubations back in the lab and to decide at what depth to sample.

All this was pretty hard, manual labor and, to my surprise, I found myself sweating and discarding some of my layers of clothes despite the cold temperatures.

Drilling a hole in the ice.

Drilling all those holes was especially hard work and made me appreciate more than ever the support we are receiving from our UMIAQ logistics team.

While drilling one of the holes we had a visitor from a ctenophore. I sent this picture to a colleague Jenny Purcell and she identified it as Bolinopsis infundibuluma common Arctic species of ctenophore.

The Arctic ctenophore Bolinopsis infundibulum.

Jenny is a world renowned jellyfish authority from Western Washington University. Ctenophores, commonly known as comb jellies are almost all predators that feed on small zooplankton. Their most distinctive features are their “combs” which consist of cilia that they use for swimming. Interestingly, ctenophores are the largest animals that swim by means of cilia. Bolinopsis is commonly found throughout the Arctic Ocean in the upper 500 meters and subsists on small zooplankton species like copeopods. Undoubtedly this individual was enjoying eating all the organisms growing at the bottom of the ice pack and we must have disturbed his/her lunch when we drilled our hole. I say his/her because Bolinopsis is a hermaphrodite.

By about 2pm we were finished and headed back and I arrived just in time to watch Zac finish his lab work and eat Twizzlers.

For dinner Steven Baer (a Ph.D. student with Debbie Bronk) and I had planned a Shabbat dinner for everyone. We are Jewish and enjoy the ritual of Shabbat that marks the end of the week and gives us all a moment to stop and reflect on the many blessings of our lives. Steven prepared an awesome dinner of pasta primavera and hosted us all to dinner. Steven had also brought candles from home and I managed to bring a bottle of wine. Because we can’t buy wine (or any alcohol) in Barrow (at least not legally) I had to smuggle it in. In the local grocery store we found a loaf of bread that resembled a Challah. Challah is a type of bread traditionally served at festive Jewish meals.

Barrow Shabbat table.

So, with everyone in attendance we took a moment to pause our work, say a few prayers, and enjoy a fantastic meal together. It didn’t last long though since most of us had to run off to finish something or other, and to get ready for tomorrow’s sampling expedition.  But at least it was a moment.