Category Archives: Marine Ecology

Ocean sediment cores provide a glimpse into deep time

Theresa on a recent cruise on the Oceanus.
Photo credit: Natasha Christman.

First year CEOAS PhD student Theresa Fritz-Endres investigates how the productivity of the ocean in the equatorial Pacific has changed in the last 20,000 years since the time of the last glacial maximum. This was the last time large ice sheets blanketed much of North America, northern Europe, and Asia. She investigates this change by examining the elemental composition of foraminifera (or ‘forams’ for short) shells obtained from sediment cores extracted from the ocean floor. Forams are single-celled protists with shells, and they serve as a proxy for ocean productivity, or organic matter, because they incorporate the elements that are present in the ocean water into their shells. Foram shell composition provides information about what the composition of the ocean was like at the point in time when the foram was alive. This is an important area of study for learning about the climate of the past, but also for understanding how the changing climate of today might transform ocean productivity. Because live forams can be found in ocean water today, it is possible to assess how the chemistry of seawater is currently being incorporated into their shells. This provides a useful comparison for how ocean chemistry has changed over time. Theresa is trying to answer the question, “was ocean productivity different than it is now?”

Examples of forams. For more pictures and information, visit the blog of Theresa’s PI, Dr. Jennifer Fehrenbacher: http://jenniferfehrenbacher.weebly.com/blog

Why study foram shells?

Foram shells are particularly useful for scientists because they preserve well and are found ubiquitously in ocean sediment, offering a consistent glimpse into the dynamic state of ocean chemistry. While living, forams float in or near the surface of the sea, and after they die, they sink to the bottom of the sea floor. The accumulating foram shells serve as an archive of how ocean conditions have changed, like how tree rings reflect the environmental conditions of the past.

Obtaining and analyzing sediment cores

Obtaining these records requires drilling cores (up to 1000 m!) into deep sea sediments, work that is carried out by an international consortium of scientists aboard large ocean research vessels. These cores span a time frame of 800 million years, which is the oldest continuous record of ocean chemistry. Each slice of the core represents a snapshot of time, with each centimeter spanning 1,000 years of sediment accumulation. Theresa is using cores that reach a depth of a few meters below the surface of the ocean floor. These cores were drilled in the 1980s by a now-retired OSU ship and are housed at OSU.

Theresa on a recent cruise on the Oceanus, deploying a net to collect live forams. Photo credit: Natasha Christman.

The process of core analysis involves sampling a slice of the core, then washing the sediment (kind of like a pour over coffee) and looking at the remainder of larger-sized sediment under a powerful microscope to select foram species. The selected shells undergo elemental analysis using mass spectrometry. Vastly diverse shell shapes and patterns result in different elements and chemistries being incorporated into the shells. Coupled to the mass spectrometer is a laser that ablates through the foram shell, providing a more detailed view of the layers within the shell. This provides a snapshot of ocean conditions for the 4 weeks-or-so that the foram was alive. It also indicates how the foram responded to light changes from day to night.

Theresa is early in her PhD program, and in the next few years plans to do field work on the Oregon coast and on Catalina island off the coast of California. She also plans to undertake culturing experiments to further study the composition of the tiny foram specimens.

Why grad school at OSU?

Theresa completed her undergraduate degree at Queen’s University in Ontario, followed by completion of a Master’s degree at San Francisco State University. She was interested in pursuing paleo and climate studies after transformative classes in her undergrad. In between her undergraduate and Master’s studies she spent a year working at Mt. Evans in Colorado as part of the National Park Service and Student Conservation Association.

Theresa had already met her advisor, Dr. Jennifer Fehrenbacher, while completing her Master’s degree at SF State. Theresa knew she was interested in attending OSU for grad school for several reasons: to work with her advisor, and to have access to the core repository, research ships, and technical equipment available at OSU.

To hear more about Theresa’s research and her experience as a PhD student at OSU, tune in on Sunday, June 10th at 7pm on KBVR Corvallis 88.7 FM, or listen live at kbvr.com/listen.  Also, check us out on Apple Podcasts!

Corals need someone in their corner

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Katherine holding all nine of the coral species she is studying for one chapter of her dissertation.

Climate change has begun to show its effects around the world in the form of warming temperatures, increased major weather events, and shrinking global sea ice. Unfortunately, one of the hardest hit species on earth is likely to be the corals, a marine animal, yes I said animal, whose beauty is well documented. Ocean acidification is limiting calcification, a process used for coral growth, and warming ocean temperatures is causing bleaching of once vibrant coral reefs.  However, there is good news for everyone who appreciates tropical oceans, the diversity of ocean life, or just plain old natural beauty. Although it’s still uncertain how corals will be able to adapt to the rapidly changing ocean environment, coral scientist Katherine Dziedzic is optimistic about the future of coral.

Katherine is a fourth year PhD student in Integrative Biology. Her research in the Meyer lab is helping to pinpoint some bright spots in coral adaptation. With the help of many collaborators around the world, Katherine is trying to find the survivors in the coral community, identify the genes theses corals are using to adapt, and then “teach” the rest of the corals how to thrive in a warmer ocean. Katherine is using a research method first developed for human disease studies called genome wide association studies (GWAS) to determine the genetic variants  that are most highly correlated with bleaching corals . Recent results have been promising and Katherine is hoping to narrow in on a potential gene, or genes, of interest. Unfortunately, progress to save the coral is slow going because much of the coral research has not been translated into action, despite the reefs’ charismatic depiction in nature documentaries.

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Katherine diving in Bocas del Toro, Panama collecting samples for her acclimation experiment.

A well-functioning national research program should function as a giant cycle to support government policy. Research improves knowledge, knowledge informs policy decisions, policy decisions lead to new areas of research. However, there are often large gaps between the scientific community, the policy makers, and the general public. Katherine hopes to help bridge the gap between science and policy decisions once she finishes her PhD work. She has completed a graduate certificate in marine resource management and plans to use her knowledge base in coral research to help governmental organizations take better care of our precious ocean resources.

If you want to hear about how Katherine got into coral research, you can listen to Katherine’s episode of Inspiration Dissemination from about two years ago. However, this time we’ll talk to Katherine about what she’s discovered about coral adaptation and her ongoing transition from PhD student to science policy advisor. Tune in Sunday, 12/4 at 7pm (PST) on KBVR-FM!

Whosits & Whatsits Galore: What do larval fish eat, and who eats them?

20150402_HatfieldGradStudentMiram_HO-4675  Tonight on Inspiration Dissemination, Miram Gleiber (a 1st year PhD student in Integrative Biology) discusses her passion for ‘le poisson’. Working underneath Su Sponaugle and Bob Cowan, Miram first got into the piscine when she was a little girl, investigating tide pools in Victoria, British Columbia. “When you take a scoop of water from the ocean you don’t realize what’s in it,” Miram muses, “… it’s a whole other world.”

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Above: Larval Fish captured in the Straits of Florida (Photos by: Cedric Guigand) on the left, and on the right, Copepods captured in the western Antarctic Peninsula: Clockwise from top left are Calanus propinquus, Paraeuchaeta antarctica, Metridia gerlachei, Calanoides acutus (Photos by: Miram Gleiber)

Because Larval fish grow up to be reef fish, which are good for biodiversity and tourism, obtaining accurate numbers of wild stock that survive the larval stage and understanding what conditions promote survival is valuable knowledge. The fish first hatch and “hang out” for thirty days in the open ocean before coming back to the reef, during which time they subsist largely on patches of zooplankton and phytoplankton that float around in the open ocean. Miram’s current research at OSU aims to understand how these patches of tiny biodiversity contribute to the growth and survival of the small fishes that eventually make their way into the view of our camera lenses and photo albums, and sometimes to our plates, as well.

To learn more about Miram and her adventures on the open sea, join us at 7pm Pacific on 88.7 FM KBVR Corvallis, or stream the talk live here!

ARSV Laurence M. Gould, a 230-foot Antarctic research vessel.

ARSV Laurence M. Gould, a 230-foot Antarctic research vessel.