Category Archives: College of Earth Oceanic and Atmospheric Sciences

Crabby and Stressed Out: Ocean Acidification and the Dungeness Crab

One of the many consequences associated with climate change is ocean acidification. This process occurs when high atmospheric carbon dioxide dissolves into the ocean lowering ocean pH. Concern about ocean acidification has increased recently with the majority of scientific publications about ocean acidification being released in the last 5 years. Despite this uptick in attention, much is still unknown about the effects of ocean acidification on marine organisms.

Close-up of a Dungeness crab megalopae

Our guest this week, Hannah Gossner, a second year Master’s student in the Marine Resource Management Program, is investigating the physiological effects of ocean acidification on Dungeness crab (Metacarcinus magister) with the help of advisor Francis Chan. Most folks in Oregon recognize the Dungeness crab as a critter than ends up on their plate. Dungeness crab harvest is a multimillion dollar industry because of its culinary use, but Dungeness crab also play an important role in the ocean ecosystem. Due to their prevalence and life cycle, they are important both as scavengers and as a food source to other animals.

Hannah pulling seawater samples from a CTD Carrousel on the R/V Oceanus off the coast of Oregon

To study the effect of ocean acidification on Dungeness crab, Hannah simulates a variety of ocean conditions in sealed chamber where she can control oxygen and carbon dioxide levels. Then by measuring the respiration of an individual crab she can better understand the organism’s stress response to a range of oxygen and carbon dioxide ratios. Hannah hopes that her work will provide a template for measuring the tolerance of other animals to changes in ocean chemistry. She is also interested in the interplay between science, management, and policy, and plans to share her results with local managers and decision makers.

Hannah working the night shift on the R/V Oceanus

Growing up in Connecticut, Hannah spent a lot of time on the water in her dad’s boat, and developed an interest in marine science. Hannah majored in Marine Science at Boston University where she participated in a research project which used stable isotope analysis to monitor changes in food webs involving ctenophores and forage fish. Hannah also did a SEA Semester (not to be confused with a Semester at Sea) where she worked on a boat and studied sustainability in Polynesian island cultures and ecosystems.  Hannah knew early on that she wanted to go to graduate school, and after a brief adventure monitoring coral reefs off the coast of Africa, she secured her current position at Oregon State.

Tune in Sunday June, 17 at 7 pm PST to learn more about Hannah’s research and journey to graduate school. Not a local listener? Stream the show live or catch the episode on our podcast.

Hannah enjoying her favorite past time, diving!

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!

Beyond doom and gloom: highlighting solutions to ocean acidification

When we hear news coverage of global environmental changes, it can easily overwhelm us. We mentally curl up into the fetal position and conclude there is nothing we can do to stave off the changes that Earth is projected to experience. One of these changes is ocean acidification–a phenomenon where carbon dioxide in the atmosphere is absorbed by the ocean. As carbon dioxide levels increase in our atmosphere, more of it is able to dissolve into the ocean and lower its pH, making it more acidic. A decrease of 0.1 pH unit in the global ocean since the beginning of the 1900s may not seem like a lot, but because pH is represented on a logarithmic scale, it actually represents about a 30% increase in hydrogen ions. This makes it harder for organisms like oysters, clams, and corals to build hard shells and skeletons. It is uncertain how this phenomenon could affect the long-term fate of these organisms, as well as the fish that depend on them.

Brian flying in a hot air balloon north of Mt. Rainer, WA.

This is where Brian Erickson comes in. Brian, a masters student in Marine Resource Management in OSU’s College of Earth, Ocean, and Atmospheric Science, observed that most curricula designed to teach high school students about ocean acidification do not discuss actionable solutions that most people can take in their everyday lives to mitigate their carbon footprints. Do student attitudes change when presented with solutions like insulating homes to save on heat, swapping incandescent bulbs with LEDs, or consolidating trips to the store to minimize gas consumption?

Brian at work during his first field biology job, studying the sexual reproduction of tropical seaweeds in St. Croix, U.S. Virgin Islands and San Blas, Panama. It’s easy to fall in love with the ocean when you snorkel on coral reefs for two summers!

A former high school science teacher himself, Brian grew up in St. Louis and received his undergraduate degree in biology from Lewis and Clark College. As an undergraduate, he first became acquainted with environmental research as a field technician in St. Croix in the Caribbean. After participating in Teach For America in New York City, he took many environmental research and education jobs before deciding to return to the ocean to bridge his interests of outdoor education and social science. As his masters draws to a close, Brian will be staying at OSU to begin a PhD in Fisheries and Wildlife working to bring multiple perspectives to marine conservation efforts in East Africa.

Helping students dissect a shark at Bronx Career & College Preparatory High School (Bronx, NY).

Taking students on their first canoe trip with Parks in Focus near Pictured Rocks, MI.

To hear more about Brian’s research and experiences in education, tune in to KBVR Corvallis 88.7 FM at 7 pm on April 15th, or stream it online here. If you’re busy at that time, the show will appear on our podcast later this week.

 

Small Differences Have Big Consequences to Keep the Oceans Happy

Swimming away from the rocky shores out to sea Grace Klinges, a 2nd year PhD student in the Vega-Thurber Lab, is surrounded by short green sea grasses swaying in the waves, multi-colored brown sand and occasional dull grayish-brown corals dot the floor as she continues her research dive. However, the most interesting thing about this little island reef off the coast of Normanby Island, Papua New Guinea, is the forest of bubbles that envelopes Grace as she swims. Bubbles curiously squeak out everywhere along seafloor between sand grains and even eating their way through the corals themselves. It reminds one of how thick the fog can be in the Oregon hills, and like a passing cloud, the bubbles begin to dissipate the further away you swim from the shore, revealing an increasingly complex web of life wholly dependent on the corals that look more like color-shifting chameleons than their dull-colored cousins closer to the shore.

Grace took ~2,000 photos for each of 6 transects moving away from the carbon dioxide seeps. She is rendering these photos using a program called PhotoScan, which identifies areas of overlap between each photo to align them, and then generates a 3D model by calculating the depth of field of each image.

These bubbles emanating from the seafloor is part of a naturally occurring CO2 seep found in rare parts of the world. While seemingly harmless as they dance up the water column, they are changing ocean chemistry by decreasing pH or making the water more acidic. The balance of life in our oceans is so delicate – the entire reef ecosystem is changing in such a way that provides a grim time machine into the future of Earth’s oceans if humans continue emitting greenhouse gasses at our current rate.

Corals are the foundation of these ocean ecosystems that fish and indigenous island communities rely on for survival. In order for corals to survive they depend on a partnership with symbiotic algae; through photosynthesis, the algae provide amino acids and sugars to the corals, and in return, the coral provides a sheltered environment for the algae and the precursor molecules of photosynthesis. Algae lend corals their magnificent colors, but algae are less like colorful chameleons and more like generous Goldilocks that need specific water temperatures and a narrow range of acidity to survive. Recall those bubbles of CO2 rising from the seafloor? As the bubbles of CO2 move upward they react with water and make it slightly more acidic, too acidic in fact for the algae to survive. In an unfortunate cascade of effects, a small 0.5 pH unit change out of a 14 unit scale of pH, algae cannot help corals survive, fish lose their essential coral habitat and move elsewhere leaving these indigenous island inhabitants blaming bubbles for empty nets. On the grander scale, it’s humans to blame for our continuous emissions rapidly increasing global ocean temperatures and lowering ocean pH. The only real question is when we’ll realize the same thing the local fishermen see now, how can we limit the damage to come?

 

The lovely Tara Vessel anchored in Gizo, Solomon Islands.

Grace Klinges is a 2nd year Ph.D. student in the Microbiology Department who is using these natural CO2 seeps as a proxy for what oceans could look like in the future, and she’s on the hunt for solutions. Her research area is highly publicized and is part of an international collaboration called Tara Expeditions as a representative of the Rebecca Vega Thurber Lab here at Oregon State, known for diving across the world seeking to better understand marine microbial ecology in this rapidly changing climate. Grace’s project is studying the areas directly affected by these water-acidifying CO2 seeps and the surrounding reefs that return to normal ocean pH levels and water temperatures. By focusing her observations in this localized area, about a 60-meter distance moving away from shore, Grace is able to see a gradient of reef health that directly correlates with changing water chemistry. Through a variety of techniques (GoPro camera footage, temperature sensors, pH, and samples from coral and their native microbial communities) Grace hopes to produce a 3D model of the physical reef structures at this site to relate changing chemistry with changes in community complexity.

Tara scientists spend much of the sailing time between sites labeling tubes for sampling. Each coral sample taken will be split into multiple pieces, labeled with a unique barcode, and sent to various labs across the world, who will study everything from coral taxonomy and algal symbiont diversity to coral telomere length and reproduction rates. Photo © Tara Expeditions Foundation

One of the main ideas is that as you move further away from the CO2 seeps the number of coral species, or coral diversity, increases which often is expressed in a huge variety of physical structures and colors. As the coral diversity increases so should the diversity of their microbiomes. Using genetic and molecular biology techniques, Grace and the Vega Thurber lab will seek to better understand which corals are the most robust at lower pH levels. However, this story gets even more complicated, because it’s not just the coral and algae that depend on each other, but ocean viruses, bacterial players, and a whole host of other microorganisms that interact to keep this ecological niche functioning. This network of complicated interactions between a variety of organisms in reef systems requires balance for the system to function. Affectionately named the “coral holobiont“, similar to a human’s microbiome, we are still far from understanding the relative importance of each player which is why Grace and her labmates have written a series of bioanalytic computer scripts to efficiently analyze the massive amounts of genetic information that is becoming more available in the field.

Grace was overjoyed after taking a break from sampling to swim with some dolphins who were very curious about the boat. Photo © Tara Expeditions Foundation

With the combination of Grace’s field work taking direct observations of our changing oceans, and her computer programming that will help researchers around the world classify organisms of unknown ecosystem function, our knowledge of the oceans will get a little less murky. Be sure to listen to the interview Sunday January 14th at 7PM. You can learn more about the Vega Thurber lab here.

You can also download Grace’s iTunes Podcast Episode!

Ocean basins are like trumpets– no, really.

We’re all familiar with waves when we go to the coast and see them wash onto the beach. But since ocean waters are usually stratified by density, with warmer fresher waters on top of colder, saltier ones, waves can occur between water layers of different densities at depths up to hundreds of meters. These are called internal waves. They often have frequencies that are synched with the tides and can be pretty big–up to 200 meters in amplitude! Because of their immense size, these waves help transfer heat and nutrients from deep waters, meaning they have an impact on ocean current circulation and the growth of phytoplankton.

The line of foam on the surface of the ocean indicates the presence of an internal wave.

We still don’t understand a lot about how these waves work. Jenny Thomas is a PhD student working with Jim Lerczak in Physical Oceanography in CEOAS (OSU’s College of Earth, Ocean, and Atmospheric Sciences). Jenny studies the behavior of internal waves whose frequencies correspond with the tides (called internal tides) in ocean basins. This requires a bit of mathematical theory about how waves work, and some modeling of the dimensions of the basin and how it could affect the height of tides onshore.

Picture a bathtub with water in it. Say you push it back and forth at a certain rate until all the water sloshes up on one side while the water is low on the other side. In physics terms, you have pushed the water in the bathtub at one of its resonant frequencies to make all of it behave as a single wave. This is called being in a normal mode of motion. Jenny’s work on the normal modes of ocean basins suggests that the length-to-width ratio and the bathymetry of an ocean basin influence the structure of internal tides along the coast. Basically, if the tidal forcing and the shape of the basin coincide just right, they can excite a normal mode. The internal wave can then act like water in a bathtub sloshing up the side, pushing up on the lower-density water above it.

It turns out that water isn’t the only thing that can have normal modes. The air column in a wind instrument is another example. Jenny grew up a child of two musicians and earned a degree in trumpet performance from the University of Iowa, and she occasionally uses her trumpet to demonstrate the concept of normal modes. She can change pitches by buzzing her lips at different resonant frequencies of the trumpet–the pitch is not just controlled by the valves.

Jenny uses her trumpet to explain normal modes.

Near the end of her undergraduate degree at the University of Iowa, Jenny discovered that she had a condition called fibrous dysplasia that could potentially cause her mouth to become paralyzed. Deciding a career as a musician would be too risky, and realizing her aptitude for math and physics, she went back to school and earned a second undergraduate degree in physical oceanography at Old Dominion University. After a summer internship at Woods Hole Oceanographic Institution conducting fieldwork for the US Geological Survey, she decided to pursue a graduate degree at OSU to further examine the behavior of internal waves.

Tune in to 88.7 KBVR Corvallis to hear more about Jenny’s research and background (with a trumpet demo!) or stream the show live right here.

You can also download Jenny’s iTunes Podcast Episode!

Jenny helps prepare an instrument that will be lowered into the water to determine the density of ocean layers.

Jenny isn’t fishing. The instrument she is deploying is called a CTD for Conductivity, Temperature, and Depth–the three things it measures when in the water.

The Breathing Seafloor

In the cold, dark depths of the seafloor across the world, microbes living in sediments and on rocks are quietly breaking down organic material and sucking dissolved oxygen out of the seawater. The continental shelf off of Oregon’s coasts, home to a fishing industry that brings in over a hundred million dollars of revenue per year, is no exception. Does oxygen consumption, and therefore carbon cycling, vary by location, or across seasons? Setting a baseline to investigate these patterns of oxygen drawdown is crucial to understanding habitats and distributions of fish stocks, but will also establish what “normal” oxygen consumption looks like off our shores. Measurements like these are also used by the Intergovernmental Panel on Climate Change (IPCC) to estimate global patterns of carbon burial. If any forces were to shift these patterns in the future, we’d at least have a baseline to allow us to diagnose any “abnormal” conditions.

Peter Chace is a third-year PhD student of Ocean Ecology and Biogeochemistry in the College of Earth, Ocean, and Atmospheric Sciences (CEOAS). Peter’s research focuses on developing a technique of measuring fluxes of oxygen across the seafloor called Eddy covariance. This technique takes high-resolution time measurements of three-dimensional velocities of water moving in turbulent whorls, or random circular patterns, within the boundary layer of a fluid like air or water. Eddy covariance has been employed to measure fluxes across air layers on land for decades, but has only recently been applied in marine systems. A point-source oxygen measurement within this turbulent layer is measured with a microelectrode and combined with the velocity data to develop a flux. Why go through all this trouble? Other ways to measure oxygen fluxes, like putting chambers over an area of seafloor and waiting to measure an oxygen drawdown, require a lot of work and give little temporal resolution.

Workers on the RV Oceanus, Oregon State’s largest research vessel, deploy a benthic (seafloor) oxygen sensor.

Peter can calibrate his microelectrodes to measure other chemicals and obtain their fluxes across the seabed, but he is mainly focused on oxygen. To measure fluxes off the Oregon coast, Pete and his advisor, Dr. Clare Reimers, will head to sea on the RV Oceanus several times this fall and winter to deploy their sensor on the seafloor for days at a time. The desk-sized seafloor lander and the microelectrode attached to it are fragile, and the rough seas offshore Oregon in fall and winter will make it a challenging endeavor. We hope they pack enough seasickness medication and barf bags!

You get right up close and personal with the ocean when you send down these instruments… and this is on a clear day with calm seas!

Since growing up as a child in New Jersey, Peter has always wanted to learn about the ocean. While studying chemistry and marine biology at Monmouth University (in New Jersey) as an undergraduate, he completed a summer REU (Research Experience as an Undergraduate) with his current advisor, Clare Reimers, here at Oregon State University. He also interned for NOAA (the National Oceanic and Atmospheric Association), analyzing the chemistry of hydrothermal vent fluids with Dr. David Butterfield. Pete revisited a hydrothermal system on a cruise to the East Pacific Rise off of Central America where he got a remarkable opportunity to dive in Alvin, the submersible that discovered the wreckage of the Titanic.

Here’s Pete in the submersible Alvin just before the dive, checking his microelectrodes.

To hear more about Peter’s research on sensor development and his seafaring expeditions, tune in to Inspiration Dissemination on Sunday, October 15th at 7pm on 88.7 KBVR Corvallis. Or stream it online here!

Breaking the Arctic ice

 

Thermal AVHRR image with land masked in black. Can see the lead coming off of Barrow Alaska very bright. The arrows are sea ice drift vectors.

Cascade over mossy rocks near Sol Duc Falls, Olympic National Park, WA.

When you hear about fractures in sea ice, you might visualize the enormous fissures that rupture ice shelves, which release massive icebergs to the sea. This is what happened back in July 2017 when a Delaware-sized iceberg broke off from the Larsen C ice shelf in Antarctica. However, there are other types of fractures occurring in sea ice that may be impacted by atmospheric conditions. Our guest this week, CEOAS Masters student Ben Lewis investigates how interactions between the atmosphere and sea ice in the Beaufort Sea (north of Alaska in the Canadian Archipelago) impact the formation of fractures. His research involves mapping atmospheric features, such as wind and pressure, at the point in time when the fractures occurred and provides insight into the effect of the atmosphere on the formation and propagation of fractures. Utilizing satellite imagery compiled by the Geographical Information Network of Alaska from 1993 to 2013, Ben has conducted a qualitative analysis to determine the location and time when these ice fractures occurred and what type of physical characteristics they possess.

Southern Alps from the summit of Avalanche Peak, New Zealand.

While fractures appear small on the satellite image, the smallest fractures that Ben can observe by are actually 250 meters wide. Fractures can span hundreds of kilometers, and the propagate very quickly; Ben cites one example of a fracture near Barrow, Alaska that grew to 500 kilometers within 6 hours!

Fractures are potentially deadly for people and animals hunting in the Arctic. As weather flux in the fragile Arctic ecosystem has become more erratic with climate change, it has been difficult for people to predict when it was safe to hunt on the ice based on patterns observed in prior seasons. Additionally, it has been problematic to track weather in the Arctic because of its harsh conditions and sparse population. A well-catalogued record of weather is not available for all locations. Modeling atmospheric conditions, such as pressure and wind, based on what has been captured by satelliteimagery, will facilitate better prediction of future fracture events.

Sunset over Sandfly Beach, New Zealand.

While pursuing an undergraduate degree in physics at the University of Arkansas, Ben was able to study abroad James Cook University in Australia, where he gravitated towards environmental physics, while taking advantage of incredible opportunities for nature photography. He also did a semester abroad in New Zealand, where he studied geophysical fluid dynamics and partial differential equations. Ben came to OSU as a post-baccalaureate student in climate science, and while at OSU, he became acquainted with his future PI, Jennifer Hutchings,  and his interest in Arctic research grew. He cites learning about snowball earth, glaciology, and the cryosphere, as providing the basis for his desire to pursue Arctic climate research. Eventually, Ben would like to pursue a PhD, but in the immediate future, he plans to keep his options open for teaching and research opportunities.

 

Characterizing off-channel habitats in the Willamette River: Fish need to cool off too!

During the summer, when the mercury clears triple digits on the Fahrenheit scale, people seek out cooler spaces. Shaded parks, air conditioned ice cream parlors, and community pools are often top places to beat the heat. If you’re a resident of Corvallis, Oregon, you may head downtown to dip your toes in the Willamette River. Yet while the river offers a break from the hot temperatures for us, it is much too warm for the cold water fishes that call it home.

Where do fish go to cool off?

As a master’s student in the Water Resources Graduate Program at Oregon State University, Carolyn Gombert is working to understand where cold water habitat is located along the Willamette River. More importantly, she is seeking to understand the riverine and geomorphic processes responsible for creating the fishes’ version of our air conditioned ice cream parlors. By placing waterproof temperature loggers along sites in the upper Willamette, she hopes to shed light both on the temporal and spatial distribution of cold water patches, as well as the creation mechanisms behind such habitats.

 

The cart before the horse: seeking to reconcile science and policy

Because the Willamette Basin is home to Cutthroat trout and Chinook salmon, the river is subject to the temperature standard adopted by the state of Oregon in 2003. Between May through October, Cutthroat and Chinook require water cooler than 18 degrees Celsius (64.4 degrees Fahrenheit). Currently, the main channel of the Willamette regularly exceeds this threshold. The coolest water during this time is found in side channels or alcoves off the main stem. While Oregon law recognizes the benefits these “cold water refuges” can provide, our scientific understanding of how these features change over time is still in its early stages.

Emerging stories

Data collection for Carolyn’s project is slated to wrap up during September of 2017. However, preliminary results from temperature monitoring efforts suggest the subsurface flow of river water through gravel and sediment plays a critical role in determining water temperature. By pairing results from summer field work with historical data such as air photos and laser-based mapping techniques (LiDAR) like in the image below, it will be possible to link geomorphic change on the Willamette to its current temperature distributions.

Between 1994 and 2000, the Willamette River near Harrisburg, Oregon shifted from a path along the left bank to one along the right bank. This avulsion would have happened during a high flow event, likely the 1996 flood.

No stranger to narratives

Prior to beginning her work in hydrology at OSU, Carolyn earned a bachelor’s in English and taught reading at the middle school level. Her undergraduate work in creative writing neither taught her how to convert temperature units from Fahrenheit to Celsius nor how to maneuver in a canoe. But the time she spent crafting stories did show her that characters are not to be forced into a plot, much like data is not to be forced into a pre-meditated conclusion. Being fortunate enough to work with Stephen Lancaster as a primary advisor, Carolyn looks forward to exploring the subtleties that surface from the summer’s data.

If you’d like to hear more about the results from Carolyn’s work, she will be at the OSU Hydrophiles’ Pacific Northwest Water Research Symposium, April 23-24, 2018. Feel free to check out past Symposiums here. Additionally, to hear more about Carolyn’s journey through graduate school, you can listen to her interview on the Happie Heads podcast.

Carolyn conducting field work on the Willamette.

Carolyn Gombert wrote the bulk of this post, with a few edits contributed by ID hosts.

Project CHOMPIN: Parrotfish, nutrients, and the coral microbiome

CHOMPIN comic.

Ecology is the study of the relationships among organisms and the relationships of organisms to their physical surroundings. The interactions of organisms can be described as a complex web with many junctions or relationships, and a single ecologist may focus on one or many relationships in a community or ecosystem. Our guest this week, Rebecca (Becca) Maher PhD student in the Department of Microbiology, is interested in the effect of environmental stressors on the coral microbiome. Let’s break this down by interaction:

  • Beneficial algae, bacteria, and viruses interact with coral by living in coral tissue and forming the coral microbiome
  • Corals interact with other organisms in the coral reef ecosystem, such as parrot fish
  • Corals are affected by their surrounding environment: water temperature, water nutrients, and pollution

Becca at the Newport aquarium for Scientific Diver Training through Oregon State University.

You may be familiar with coral bleaching and coral reef decline from our past episodes. Corals form a mutualistic relationship (both organisms benefit) with algae, where algae take shelter within coral tissue and provide the coral with food from photosynthesis. It is well known that high temperatures lead to coral bleaching, or a shift in the coral microbiome resulting from the loss of beneficial algae that live within the coral. Coral bleaching is often fatal.

Becca is interested in other aspects of the coral microbiome, such as differences in the symbiotic bacterial communities brought about by nutrient enrichment from agricultural run-off and overfishing. Do corals in nutrient rich water have a different microbiome than corals in nutrient poor water? Do corals in highly fished areas have a different microbiome than corals in fish-rich areas? In overfished areas, predatory fish (e.g. parrotfish) may bite coral (hence Project CHOMPIN), and so how does the coral microbiome respond after wounding by parrotfish?

Becca diving at the Flower Garden Banks National Marine Sanctuary in the Northwest Gulf of Mexico for her undergraduate thesis at Rice University.

These questions are relevant for our knowledge of environmental factors that threaten coral reef ecosystems. Corals are in decline globally and with them are the high diversity of marine species that gain shelter and substrate from the coral reef. The information gained from Becca’s research may be informative for policy makers concerned with agricultural practices near marine areas and fishing regulations.  Rebecca is traveling to Morrea, French Polynesia this August to set up her field and laboratory experiments at the Gump Biological Research Station.

This upcoming trip is highly anticipated for Becca, who has been pursuing research in marine ecosystems since her time at Rice University. After working with her undergraduate mentor Adrienne Correa at Rice, Becca’s general focus on Ecology shifted to a focus on Marine Ecology. For Becca, her project at Oregon State in the Vega Thurber Lab is a harmonious mix of field work, high-level experimental design, bioinformatics, and statistics—a nice capstone for a Marine Ecologist with aspirations for future research.

Hear more about Becca’s work with corals the Sunday at 7 PM on KBVR Corvallis 88.7FM. Not a local listener? Stream our broadcast live.

Using sediment cores to model climate conditions

In the lab of Andreas Schmittner in the College of Earth, Ocean, and Atmospheric Sciences, recently-graduated PhD student Juan Muglia has been developing a climate model to understand ocean current circulation, carbon cycling, and ocean biogeochemistry during the last ice age, focusing on the Southern Ocean surrounding Antarctica.

Juan has developed a climate model using data gathered from sediment cores, which are samples from the ocean floor that provide researchers with a glimpse into the elemental and organic composition of the ocean at different points in time. Scientists can acquire insight into the characteristics of the Earth’s past climate by analyzing the geologic record spanning thousands of years. Modeling the conditions of the last ice age, which occurred 20,000 years ago, allows researchers to better understand how the Earth responds to glacial and interglacial cycles, prompting the transition between cold and warm phases (we are currently in a warm interglacial period).

The process of generating an accurate climate model consists of tuning parameters embedded in the physics equations and fortran code of the model, to reproduce characteristics directly observable in modern times. If researchers can validate their model by reproducing directly observable characteristics, the model can then be used to investigate the climate at points in time beyond our direct observational capacity.

Since it’s not possible to directly measure temperature or nutrient composition of the ocean during the last ice age, Juan uses an indirect signature that serves as a proxy for direct measurement. Three isotopic sediment tracers, including 15Nitrogen, 14Carbon, and 13Carbon, are incorporated into Juan’s climate model as proxies for biological productivity and current circulation in the ocean. Investigating changes in the elemental composition of the ocean, also known as biogeochemistry, is important for understanding how climate and biology have transformed over thousands of years. The ocean serves as an enormous reservoir of carbon, and much more carbon is sequestered in the ocean than in the atmosphere. The exchange of carbon dioxide at the interface of the ocean and atmosphere is important for understanding how carbon dioxide has and will continue to impact pH, ocean currents, and biological productivity of the ocean.

Even as a kid, Juan dreamed of becoming an oceanographer. He grew up near the ocean in Argentina, surrounded by scientists; his mom was a marine botanist and his dad is a geologist. During his undergraduate studies, he majored in physics with the goal of eventually becoming a physical oceanographer, and his undergraduate thesis consisted of building fortran code for a statistical physics project. After finishing his post-doctoral studies at OSU, Juan plans to return to his hometown in Argentina, where he hopes to develop a model specific to the Argentinian climate.