# 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.

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.

# GROWing Healthy Kids and Communities

Physical activity has many benefits for health and wellness. Physical activity can help us control our weight, reduce our risk of diseases including many cancers and type 2 diabetes, help to strengthen our bones and muscles, and improve our mental health. Yet despite the benefits, many don’t get the recommended amount of physical activity. Our guest this week, Evan Hilberg from the College of Public Health and Human Sciences and the Department of Kinesiology, is investigating factors that influence physical activity of children in rural communities. Research focused on physical activity in children disproportionally centers around children in urban communities. Children in rural communities may have different limitations to physical activity. For example, rural children are more likely to take the bus to school instead of walking and commutes may take up to two hours each way. This leaves little time for physical activity outside of school hours. With his advisors, John Schuna and Kathy Gunter, Evan is analyzing data collected as part of the Generating Rural Options for Weight- Healthy Kids and Communities (GROW HKC) to better understand when children are active during the school day and factors that might limit their physical activity.

### Recess and Wellness

Evan taking blood samples for cholesterol and glucose testing at a Community Wellness Fair.

One area of interest for Evan and the GROW HKC project are the variables that may predict changes in Body Mass Index (BMI) over a three-year period. Through this longitudinal study that involves over 1000 rural Oregon elementary school children, Evan will identify correlates of BMI change such as physical activity levels, age, sex, teacher, and school. Additionally, Evan is analyzing data that will hopefully provide more insight into specifically what times during the school day children are active. By obtaining a classroom schedule from teachers and measuring activity with accelerometers and pedometers, Evan can infer if children are physically active during recess, P.E., classroom activity breaks, or other times during the school day. Finally, Evan’s data will examine the reliability of different objective measures of physical activity, such as pedometers and accelerometers. The ability to compare outputs from different devices is limited by changes in device hardware and software, as well as the ways in which data is processed within those devices. The examination of these devices may inform procedure for future physical activity research for children and adults to help comparability across different devices and different studies.

### A School of Thought

A clear understanding of the factors effecting physical activity in rural school children will aid in structuring the school day to maximize each child’s opportunity to be physically active. Data generated through GROW HKC my reveal patterns that younger children are more active during unstructured play during recess, whereas older children prefer sports-focused activity in P.E.. This type of research could inform recommendations for state-mandated physical activity at schools such that school day structure and physical activity opportunities are tailored to the diverse needs of kids in rural communities.

### Full Circle

Evan grew up as an active kid and selected a college where he could play baseball. He landed at Linfield College in McMinnville, Oregon where his interest in Exercise Science grew through volunteering in community health outreach and research with his advisor, Janet Peterson. Evan learned that his education went beyond the classroom through his interactions with the community. Evan decided to pursue graduate school and earned a Master’s degree in Exercise Physiology from Eastern Washington University. During his Master’s, Evan gained more experience with community and public health research as an AmeriCorps employee with Let’s Move, Cheney”, a local coalition inspired by Michelle Obama’s national campaign. Thereafter, Evan volunteered with the GROW HKC project, and applied to graduate school at Oregon State. Since beginning his doctoral studies with a concentration in physical activity and public health, Evan has completed a Master’s in Public Health in Biostatistics and maintains a full-time job as a Medical Policy Research Analyst with Cambia Health Solutions.

Tune in to 88.7 FM KBVR Corvallis this Sunday November, 12 at 7 pm to hear more about Evan’s research and background in Exercise Science. Click here to stream the show live.

Evan at the California-Oregon border on a self-supported bike trip to San Francisco down the coast.

# Secrets of the Black Cottonwood

Ryan cultivated his interest in plants at a young age while checking wheat fields with his dad on the family farm near Beltrami, MN.

Growing up on a family farm in North Dakota, Ryan Lenz loved learning about wheat – specifically the things that made wheat varieties different. Why were some taller or shorter than others? Why did some have more protein? After gaining skills in molecular biology at North Dakota State University with a Bachelor of Science in Biotechnology, Ryan interned with a biotech company where he was finally able to make the connection between wheat varieties and the genes that make them different. This experience sparked his interest and led him to earn a Master’s degree in Plant Sciences at his alma mater and eventually brought him to OSU’s Department of Botany & Plant Pathology to study host-pathogen interactions as a PhD student with Dr. Jared LeBoldus.

Using black cottonwood (Populus trichocarpa) – a native tree to the western US – Ryan is working to reveal the genes responsible for making woody plants susceptible to fungal disease and those that give the fungus the ability to infect trees. The fungus of interest, Sphaerulina musiva, causes leaf spot and stem canker on cottonwood trees – the latter disease being more severe as it girdles the trees and causes the tops to break off.

Ryan tending to his tissue culture plants in the LeBoldus Lab.

The fungal pathogen was first found in the eastern United States in association with the more resistant eastern cottonwood (Populus deltoides), but has worked its way westward putting the susceptible black cottonwood at risk. This fast-growing cottonwood is a foundation species in riparian areas and provides erosion control. Not only are these trees important ecologically, they are also important in forest agriculture for their uses in making pulp for paper, biofuels, building materials, windbreaks, and for providing shade.

Ryan and his wife, Rebecca, enjoying the beautiful Pacific Northwest.

To learn how the tree and fungus interact, Ryan employs advanced molecular techniques like the CRISPR-Cas9 system to edit genes. To put it simply, he tries to find the important information in the plant and fungus by making changes in the genetic code and then seeing if it has a downstream effect. The implication of his work has two sides. On one hand, Ryan is trying to provide cottonwood breeders with insight to make a more resistant tree to be grown in the western US. While on the other hand, he is working to establish the black cottonwood as a model system for other woody hosts susceptible to necrotrophic fungi – those that feed on dead tissue. As a model system, the secrets of the black cottonwood would be unveiled, providing a blueprint of valuable information that could be applied to other woody trees.

One day, Ryan hopes to move back to the Midwest to be a plant researcher near his family’s farm.