Wesley Huffman inspecting his salt marsh mesocosm for an experiment.
COVID-19 has drastically changed all aspects of our lives, including how we teach, do research, and stay connected at UConn. The Department of Marine Sciences is adapting to a new normal, and this Fall Semester has been unlike any other.
Classes are mostly online, however, some courses have continued in-person. In these situations, students are of course practicing social distancing and wearing their masks. Classes which feature research cruises and scuba diving were thankfully able to carry out these activities safely. Graduate student Wes Huffman comments on his positive experience with his online classes. “I initially thought an online discussion-based course would be challenging, with either no one discussing or people talking over each other. I have also previously found online lectures to be more challenging to pay attention to. However, video-based online discussion has worked exceptionally well and has been on par with similarly styled in-person courses.”
Research is affected but still continuing safely. Everyone working indoors is required to wear masks, social distance, and check in and out of each lab space (for contact tracing). Most professors and students are working from home often or even entirely, only coming to campus when it is necessary. This has resulted in many adaptations to ongoing research. Wes shares, “One of my projects that has been ongoing during COVID is a series of mesocosm experiments… Remote monitoring and control of this experimental system have been critical in allowing me to continue working from home when possible while streamlining in-person sampling. This not only mitigates potential COVID exposure but has improved the quality of data gathered by being able to fine-tune parameters more frequently than otherwise feasible while in the lab.”
Graduate students prepping the sampling rosette as part of the Oceanographic Expedition course.
In such a unique situation, new opportunities have also been possible. Molly James, a graduate student, shares her experiences. “A great opportunity that I wouldn’t have been able to do under normal circumstances is attend meetings of the Governor’s Council on Climate Change (GC3). My advisor suggested I participate in the virtual meetings for the GC3’s Science and Technology Working Group. As a result, I produced information sheets for the public detailing climate change impacts and projections in Connecticut.”
This year, mostly everything has been online. Seminars and brown bags are both continuing regularly on WebEx. However, these weekly events were set times that many of us from the department would step away from our individual work and get to see each other. The online meetings, both professional and social, bring feelings of isolation, as expressed by many people.
On the bright side, since we’re all staying at home more than usual, this seems to have caused a widespread interest in pursuing new hobbies. Molly shares, “Some silly results of quarantining are rearranging my bedroom and living room (more than once) after becoming mildly addicted to DIY and home decor YouTube channels; baking many loaves of bread; attempting to become a jogger/runner; doing a language exchange with a friend in Seoul; and many hours on friend group video chats.”
A student using a salinometer outside during Prof. Pieter Visscher’s in-person geomicrobiology class. (Bri Diaz/UConn Photo)Temperature and Relative humidity sensors deployments to the City of New Haven. Molly James (left) and Kay Howard-Strobel (right) are attaching them.
Dierssen and Garaba using a spectrometer to measure the spectral properties of washed-ashore plastics at the Mystic Aquarium.
We’ve all heard stories about the garbage patches that are kilometers wide floating out in the ocean. While the garbage islands that many of us imagine are much closer to fiction, there is definitely a lot of plastic in the ocean, and most of it is in the form of microplastics (<5mm). This makes it difficult to identify and track the plastics that are floating around.
Satellites are able to find things like plankton blooms in the ocean by their spectral information (such as color). However, when it comes to plastics, they all have different colors and compositions and can be very small in size. This makes it tricky to distinguish plastic floating on the ocean surface.
In a recent publication, Professor Heidi Dierssen and a former postdoctoral researcher from her lab, Dr. Shungu Garaba now at the University of Oldenburg in Germany, built a database of the spectral information of many different types of plastics. They measured spectral reflectance, which represents the “color” of the objects, in the ultraviolet (UV), visible, and infrared (IR) parts of the spectrum. As explained in the publication, “The spectral reflectance of an optically active object (e.g. plastic, coral, seawater, algae, sediment) has a characteristic shape that explains how it can reflect or absorb light. The spectral shape is a combination of peak (reflection or fluorescence) features and trough (absorption) features that are distinctive optical properties of the objects.”
The figure above is an example of a spectral reflectance measurement of marine microplastic particles, showing dips (troughs) of the curve highlighted with gray lines. These dips, called absorption features, are unique to the object and can help identify the type of plastic. Dashed lines represent standard deviation.
Assorted marine-harvested microplastics.
Dr. Dierssen and Dr. Garaba sampled many different types of plastics that are representative of what would actually be found floating in the ocean. “Many research studies on marine plastics purchase new plastic bottles and other debris for their studies. This does not represent the actual objects found floating on the ocean surface and their environmental state,” Dierssen explains. The types of plastics that were sampled included microplastics (0.3- 5 mm), macroplastics (>5mm), and new plastic polymer pellets (for comparison). Microplastics were collected from the Atlantic and Pacific Ocean using surface-sampling nets. Macroplastics were sampled at the Mystic Aquarium, as part of a traveling exhibit raising awareness about plastic pollution, titled “Washed Ashore: Art to Save the Sea.” These plastics (buoys, containers, ropes, toys, nets, etc.) were collected from beach clean-ups on the West Coast. Dierssen describes that “their colors and material had been weathered by the sun and exposed to ocean turbulence. This provided a much closer library of real plastic objects that would be observed floating at sea than if we purchased new [plastics].”
The large plastics washed ashore are easily identifiable, but much less is known about the composition of the small microplastic particles found floating at the sea surface. To address this, Dierssen and Garaba also measured reflectance from new plastic pellets of 11 different polymer types. Absorption features of microplastics were compared to the plastic pellets to determine the closest matching spectral properties. The microplastics were most similar to low-density polyethylene and polypropylene often used in bottles and packaging material.
The measurements of the different types of plastics from this study are available in an open-access database as a reference for others. This data will help with remotely sensing and tracking plastics in the ocean, and eventually be used to identify the types of plastics floating around from satellites! As Garaba states, “Our contribution to the monitoring of plastics is the groundwork of understanding the key properties of plastics that can be used to develop algorithms/models/statistical approaches to derive essential descriptors about the plastics from remote sensing tools since these plastics have an optical signature or a unique light signal.”
Dierssen and Garaba recently submitted a NASA proposal to continue their collaboration to develop ways to remotely sense microplastic particles across the global ocean. Look forward to hearing more from them in the future!
Citation:
Garaba, S. P., & Dierssen, H. M. (2020). Hyperspectral ultraviolet to shortwave infrared characteristics of marine-harvested, washed-ashore and virgin plastics. Earth System Science Data. DOI:10.5194/essd-12-77-2020
This fall, the Department of Marine Sciences (DMS) enthusiastically welcomed Dr. Leonel Romero as a new assistant professor in physical oceanography. The DMS began the interview process for new physical oceanographers last spring. Romero’s interview was in March, right before the university closed for the COVID-19 pandemic. This unique situation brought on a set of challenges in starting work at the department, including some delays and getting used to a new way of working, but Romero has been able to do much of his work remotely, and felt welcome despite the situation.
“A lot of the people in the department have been super helpful with my transition,” Romero says. He looks forward to eventually be able to return to the department in person so that he can meet more of his colleagues. He was able to move into his office and lab space, but his biggest challenge is starting a lab group.
At UConn, Dr. Romero will be continuing his work on upper-ocean processes, ocean waves, and air-sea interaction. Previously, Romero was an Associate Researcher at the University of California Santa Barbara. In 2008 he received his Ph.D. in Oceanography from the Scripps Institution of Oceanography. He received a bachelor’s degree in Physics from the University of California, San Diego, in 2002.
Romero’s journey to becoming a physical oceanographer started early on in his life. He grew up in Mexico City and always loved math and physics. Before high school, he came across Hawking’s Brief History of Time and was fascinated by it, which led him to pursue an education in astrophysics. Romero moved to San Diego for university, where he became fascinated with the ocean through surfing and his work. He became an undergraduate research assistant at Scripps Institution of Oceanography. “We were trying to understand the drifts of floats in the Southern Ocean,” Romero said, “It’s important to understand those currents because they regulate our climate, and I found it super rewarding to study ocean physics and the environment.” When he took astrophysics classes, he found them too abstract, and became passionate about oceanography.
Romero during an experiment in the Gulf of Mexico, deploying pink dye to study the transport and mixing by ocean currents.
While pursuing his Ph.D. in oceanography, Romero focused on air-sea interactions. “In order to improve our understanding of how weather and climate work, we actually need to understand ocean waves and I found that fascinating, and I pretty much dedicated most of my career towards that.” Romero moved to Santa Barbara as a researcher to continue work on upper-ocean and interdisciplinary processes, such as utilizing runoff as a tracer for an ecological project. Romero decided to pursue a tenure-track position after teaching a class on waves, tides, and estuarine processes. He was drawn to UConn because of our department’s work focusing on air-sea interactions.
At UConn, Romero will work on an NSF-funded project to study interactions between waves and fronts, and their correlation with wave breaking. “If you have fronts, you happen to have more wave breaking, and so that has potential implications for how the CO2 gets into the ocean.” This project is “purely numerical with coupled ocean wave models,” which can all be done remotely. Romero also plans on starting an observational/modeling group at Avery Point in the future.
Outside of research, Romero has been enjoying the scenic CT coastline. He loves to surf and go on walks in the area. As a seafood lover, he has been enjoying the abundance of good local seafood.
Dr. Amina Schartup is a Marine Sciences alumna who recently started as an assistant professor at Scripps Institute of Oceanography, University of California, San Diego. She is currently working on setting up her lab at Scripps. Amina received her PhD in Oceanography in 2012. At UConn, she studied mercury cycling in sediments with Dr. Robert Mason. This interview was carried out by Patricia Myer, a current graduate student, on October 23rd, 2020. We discussed her current situation, unique career path, and advice for grad students.
Patricia: Would you mind telling me about setting up a lab during these times?
Amina: I think that setting up a lab in normal circumstances is quite challenging, because you have so many moving pieces. It’s really difficult to know where to start. You have to build the lab, the physical space, but then you also have to build the group – build that cohesion between you and whoever comes into your group, and start a culture. People don’t think about it sometimes, but that’s when you decide what the culture of your group is going to be.
You also have to equip your lab. You need to buy the instruments, deal with salespeople, choose what you want down to the smallest beaker. It’s just a lot of details, and now we’re doing a lot of this remotely, without the option to meet in person. Bringing in students and creating that culture in your group when you cannot be in the same room is not ideal.
Q: What path did you take to get to your current position from UConn?
Amina: After I graduated in 2012, I started as a postdoc at the Harvard School of Public Health, working with Elsie Sunderland. I was there for two and a half years, and then she actually moved to a different position at the Harvard School of Engineering and Applied Sciences. I moved with her as a Research Associate until 2017. In 2017 I started an AAAS Science and Technology policy fellowship. I was placed at the office of Polar programs at NSF, and I was there until 2019. After that I came to Scripps.
When I started the AAAS position, I was trying to figure out what I wanted to do career-wise. I wasn’t decided on whether I wanted to remain in academia or not. There were three reasons why I wanted to do this fellowship. One – I thought that if I wanted to stay in academia, considering that a lot of students who get a PhD do not necessarily end up in academia, I thought it would be difficult for me to advise them on career paths and choices if I had no experience with what a career looks like outside of academia. AAAS has such an amazing track record at placing PhDs in all kinds of private and government positions, they have a vast network of people that you can reach out to at any time. I thought it would be great to have these connections, so if my students decide they don’t want to stay in academia, I have someone to reach out to, and I also know what these jobs look like.
Another reason is that I did not want to commit to a career path in academia for myself without knowing the other options out there, and whether this is the one thing that would work well for me in the long-term. This exposed me to those other jobs. I decided to go back to academia.
The other reason was that if I want to go into academia, I needed to know how proposals work and how to get funded. Being at NSF is a better place to learn how to write a good proposal, what gets funded, and how the review process works. A lot of people go into NSF as a rotator later on as academics. I thought it would be really nice to go in early on before I start the position, and that would increase my chances as I pursue my academic career. Those are the main reasons why I wanted to go into AAAS.
The difficulty was that if you want to go to academia, you have to maintain a productivity output of sorts. Which means I actually had two jobs. I had to do my AAAS job and I also had to do my academic job, so I was working three 11-hour days and one 7-hour day at NSF. Then the rest of the week would be science work, so, papers and research projects. I went out to the field on vacation time and did all kinds of crazy things to make sure I could still produce science while I was at NSF.
Amina in North West River, Labrador Canada incubating soil cores.
Q: What did you study at UConn, and how does it compare to what you do now?
Amina: I did my PhD in Oceanography with Rob Mason, and I studied mercury cycling in sediments mostly for my PhD work, and then I had one side project where I was looking at what was happening in the water. I would say that the work I’m doing now is still quite similar, I still work on the same element for the most part. I think that where I grew was on the scale. I was mostly focused on smaller coastal areas, and as I moved through the different positions, I think the scale of my research changed to a more global and more of a systemic perspective, rather than just one aspect of the system such as sediment. This still in flux, this is partially what I’m trying to decide in my new position. What is it that I want my research to look like and what is it that I want my lab to do? It’s actually quite exciting.
Q: How much freedom do you have in choosing exactly what your lab does? I know a lot of people working on their PhDs aren’t sure if they’re locked into similar projects for the rest of their career.
Amina: In theory, you have unlimited choices, I can go out there and decide I want to study leaves. Your limitations are your own capabilities and knowledge of course, but also what people are willing to let you get away with. As a scientist, you can be curious about anything, but at the end of the day you need to get your research funded and your papers published. Somehow these aspects are also related to what people’s perceptions are of your capabilities.
I recently submitted a proposal about something that I thought was super interesting, and I really wanted to do, and I thought that I could actually do it – that even if I ran into difficulties that I could figure it out. And the proposal reviewers said ‘you have no experience in this thing, you can’t do it.’ So that’s where you get the pushback, you want to try something new, you want to try something different and branch out. You think you can do it, but people tell you that you can’t, so they don’t give you the money to actually try it out. I think that’s the issue.
When you’re trying to do something new, you have two options. You can work with somebody who is already well-established in the field and get in this way. Or, you can do the preliminary work and publish it, and show that you know something, and then you can rely on this to try something new.
Q: What would you say during your grad school experience best helped you prepare for your career?
Amina: It’s really difficult to pinpoint exactly what made a difference. There are a few things. One thing was that I didn’t have a set project that I came in to work on. I really had to come up with my own science, and I didn’t necessarily have all the extra cash that comes in with a project to get analysis done and so on. I had to just run around the department and figure out how to use the instruments that were available, and think hard about how I can use my resources to do impactful science. Just having the freedom to think through it and work through it at my own pace, without the pressure of being on a specific project that needed deliverables, I think in the long run was helpful to me. I got lucky that what I tried out worked, it could have not worked and impacted my career in a negative way. So, in a way it was a combination of luck and the fact that I could just run around and do whatever I wanted, which was really nice.
Q: What advice would you have for current grad students?
Amina: I think maintaining a life on the side is really important. I had two children during my PhD, my son was born in my first year and my daughter was 7 months at my defense. My husband always jokes that having children was really good for me because it forced me to have a life outside of the lab. That if it wasn’t for them, I would be there 24/7, and I think that’s true. I think that being forced to get out of that space and stopping the constant working and pushing yourself to extremes, and having a side life is good. It gives you the time to let ideas mature in your head, because I think our brains continue to work even if we’re not necessarily focused on something. So, if you’re stuck with an issue in the lab and can’t see the big picture, I think having some time and space outside will let your brain do the work in the background.
I think another thing that is really important is understanding that this is a personal journey, it is a collaborative journey, but it is a personal journey. You should make sure that you work with people and not compete with people, and really think about the fact that we all have our own paths to success, and it’s really hard to tell what somebody’s path will look like, you can only see it in hindsight. So, if you’re competing on a day-to-day or week-to-week basis, it’s not good, because you don’t know where the person is going to go, and where you are going to go. If I was really focused on looking at what everybody was doing and how this reflects on me, and whether I fit in, having two children, I probably would have given up, because I wasn’t as productive as I should have been or working as hard as I should have been. I just left that on the side and did what I needed to do. And it just worked!
Later this year, Dr. César Rocha will be starting as a new assistant professor in the Department of Marine Sciences (DMS). DMS has been searching for new physical oceanographers to join the ranks of the faculty. It is with great enthusiasm that we welcome César to the University of Connecticut and to the scenic Avery Point campus.
Professor Rocha is currently a postdoctoral fellow at the Woods Hole Oceanographic Institution. In 2018, he received his Ph.D. in Physical Oceanography from the Scripps Institution of Oceanography at University of California, San Diego. Before then, he studied at University of São Paulo in Brazil, where he completed his B.S. in Oceanography and M.Sc. in Physical Oceanography.
Rocha, who hails from Brazil, reflected that his childhood played a large role in his decision to study the ocean. “Even though I grew up in a landlocked city, I used to spend every summer in my family’s house on Brazil’s Green Coast.” He continued, “in those lengthy vacations, I developed an awe for the ocean and this led me to pursue oceanography in college.”
He started oceanographic research as an undergraduate and “never stopped.” Along the way, he is glad to have had “wonderful mentors” to help shape his academic and professional career. Currently, Rocha’s research interests lie in mesoscale and sub-mesoscale flows in the ocean. This scale ranges from 1 to 100 kilometers and includes features such as eddies, fronts, and filament flows of the mixed layer and pycnocline, the layer of the ocean characterized by large density differences. Flows may originate at large scales and cascade to smaller ones, which mix the ocean and cause turbulence. Rocha explains, “Turbulent oceanic flows are responsible for both horizontal and vertical transport of properties such as heat, freshwater, nutrients, and biogeochemical tracers.”
While in graduate school, Rocha was a NASA Earth and Planetary Sciences Graduate Fellow. At UConn, he will continue his relationship with NASA through two NASA-related projects. The first will investigate sub-mesoscale eddies that are generated near topographic features on the ocean floor, which is a part of the Surface Water and Ocean Topography (SWOT) Mission. The second will be with the Submesoscale Ocean Dynamics Experiment (S-MODE), in which he and collaborators will deploy a flotilla of Saildrones, wind and solar-powered uncrewed surface vehicles, to study vertical transport in kilometer-sized fronts of the California Current.
Beyond research, Rocha is enthusiastic about teaching and mentoring. “I enjoy breaking down and distilling complicated concepts and explaining them to others,” he said. “I am committed to continuing to develop myself as an effective instructor.” He plans to create a new hands-on course called Research Computing in Marine Sciences, in order to teach data science and analytical tools in Python.
Rocha is looking forward to the personal and interdisciplinary community at DMS. “I like the idea of being in a department that is big enough to have a robust graduate and research programs, yet small enough so we get to know everybody,” he said. “I am eager to interact with colleagues from all areas of marine sciences.”
In his spare time, Rocha is working on his culinary skills. He also voraciously reads in both English and his native Portuguese. One of his favorite American publications is The New Yorker, for its fascinating and well-produced content.
On the first floor of the Marine Sciences Building, it’s hard to miss the office door belonging to Kay Howard-Strobel because of its humorous sticker, “SAVE THE CRABS, THEN EAT ‘EM.” If you haven’t met Kay, you’ll probably be familiar with some the activities she’s been involved with at Avery Point.
Kay received her bachelors from the University of Mary Washington, where she majored in biology and geology. Then she completed her masters from the Virginia Institute of Marine Sciences (VIMS) in marine geology. Her thesis looked at Chesapeake Bay mud by using spatial autocorrelation to characterize dredge disposal sites in the Chesapeake Bay. “I found sand and mud was even way more fun than rocks and minerals,” she commented.
How Kay got to UConn is an interesting coincidence: “While at VIMS – one of my advisors hosted a visiting professor named Frank Bohlen,” she said. “After graduate school, I moved to Rhode Island with my husband and sent Frank a letter – and here I still am.” For 30 years, Kay has been a researcher in DMS, the first half working with Frank and second with Jim O’Donnell.
Currently, Kay manages, maintains, and configures various oceanographic instruments for field observations, including portable and mooring Acoustic Doppler Current Profilers (ADCPs), profiling and stationary Conductivity-Temperature-Depth (CTDs) sensors, suspended sediment sensors, Autonomous Underwater Vehicles (AUVs) and gliders, nutrient sensors, buoys, and more.
Kay deploys and recovers these sensors on all types of field campaigns too. Work in the field is very weather dependent and preparation constant, so she is ready to go on a moment’s notice. The variety of field work Kay has done is staggering. She said, “Every project is memorable in some way, shape or form… whether traipsing through marshes and walking amongst reef balls with graduate students, deploying buoys in western LIS off the R/V Connecticut at the crack o’ dawn, squeezing under bridges on the Maritime Skiff, riding flood-gate currents in a johnboat, or running CTD profiles down the Sound on a flat, calm summer day on the Osprey… they’re all good.”
Throughout her three decades at UConn, Kay has been a part of many significant observational projects. One in particular is the Long Island Sound Coastal Observatory, now know as the Long Island Sound Integrated Coastal Observing System (LISICOS). Initially, it started as a buoy in the Thames River that transmitted data in real-time back to Avery Point, which she and David Cohen developed. Now, LISICOS is an interdisciplinary network of buoys, radar, weather stations, and water quality measurements. Public, private, and state users have to come to rely on that data for recreation, policy, and monitoring
Kay also enjoys CrossFit and playing soccer. She is one of the longest standing, most valuable members of the Department’s Friday afternoon pick-up soccer games.
DMS is enriched by and fortunate to have Kay Howard-Strobel as an expert observationalist in our midst.
It has been over 50 years since the University of Connecticut established Avery Point as a regional campus and nearly 40 years since the formalization of the Department of Marine Sciences (DMS). At that time, national feminist and civil rights movements were in full swing as well. In the decades that followed, especially the past 20 years, a primary focus of these movements has been increasing and retaining diversity in science, technology, engineering, and mathematics (STEM), which includes oceanography. Since the early 2000s, DMS has successfully narrowed the gender-gap among faculty members.
Barbara Welsh was the first female faculty member in DMS. She was hired in the 1980s and helped establish hypoxia monitoring and nitrogen management programs in Long Island Sound. Her research revealed phytoplankton blooms and the resulting alarmingly low oxygen concentrations in Western Long Island Sound in the summer.
The next female professor to join was Annelie Skoog, who studies marine organic matter cycling. Another early female leader was Associate Professor in Residence Patricia Kremer, who studied gelatinous plankton. After Barbara retired, Annelie remained the only tenured female faculty member. All other women faculty were research scientists and not professors. The most common title being Research Professor, with levels assistant, associate and full.
A few members of the department recalled a faculty meeting in 2002, in which half the members present were women. However, as the only female tenure-track professor present, Annelie was the only woman allowed a vote.
As a part of larger UConn initiatives to promote diversity and opportunities for underrepresented groups, DMS sought to grow as a department and recruit talented new faculty for hire. In 2005, Ann Bucklin became the first female department head and lead many efforts to formalize department proceedings.
Since then, Heidi Dierssen, Penny Vlahos, Julie Granger, Kelly Lombardo (who moved to Penn State University in 2019), Melanie Fewings (who moved to Oregon State University in 2018), Samantha Siedlecki, and Catherine Matassa have joined the tenure-track faculty ranks.
Additionally, Sandy Shumway, Jamie Vaudrey, and Jennifer O’Donnell have been members of the research faculty and key contributors to the Department. Claudia Koerting has been an integral part of developing the undergraduate program and maintaining instrumentation. A partnership with Mystic Aquarium added four women – all active and successful marine researchers – as affiliate faculty-in-residence: Tracy Romano, Maureen Driscoll, Laura Thompson, and Ebru Unal.
After conversations with many of these stellar scientists, it became clear that the culture in science overall has shifted greatly. Both Claudia and Penny commented that neither of them had any female professors throughout their entire academic careers. Whereas current graduate and undergraduate students can attest that female professors in the sciences are now entirely usual. However, disparities among different scientific disciplines remain. Today, the percent of people in physics and engineering identifying as female at the doctorate level is approximately 20% (Women in Physics and Astronomy 2019 Report, American Institute of Physics).
The culture that has been cultivated and continues to grow in DMS strives for diversity, inclusion, and equity on all academic levels including students, staff, and faculty.
On a final note, here are some statistics based on current departmental records. As of April 2020, all four research staff, six of eight postdoctoral research associates, 7 of 18 tenured or tenure track faculty, and four of five research faculty are women.
Image courtesy of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), https://www.jamstec.go.jp/e/about/press_release/20180523/
It’s finally springtime in the Northeast USA, so gardeners are looking to fertilize their plants and flowers. Have you ever stopped to wonder what is actually in the big bags of soil you spread on your lawn?
In most cases, it is a mixture of nitrogen and phosphorus. Both are limiting nutrients for the base of the food chain, aka plants. Phosphorus makes its way into soil and the ocean through weathering of rocks. Nitrogen, on the other hand, is trickier, because although it makes up over 70% of the atmosphere, this gaseous form (N2) is unusable by plants and animals.
So how does nitrogen get from the atmosphere into a usable form? The process is called “nitrogen fixation.” On land, bacteria in soil do the heavy lifting by converting N2 into organic nutrients like ammonium (NH4+) and nitrate (NO3–) that are usable by plants. In the ocean, blue-green cyanobacteria are the most abundant type of bacteria to fix nitrogen. Collectively, these organisms are called diazotrophs, and account for close to 90% of natural nitrogen fixation.
In a recent collaborative publication, Associate Professor Julie Granger and Professor Craig Tobias contributed their expertise on the nitrogen cycle in the ocean. The study included scientists from various institutions and focused on standardizing procedures for measuring diazotrophic activity in field sample incubations.
Oceanographers are interested in understanding the magnitude and rate of nitrogen fixation by diazotrophs. These rates vary significantly depending on the location, whether coastal or open ocean, poles or equator, shallow or deep. Ultimately, scientists aim to evaluate what controls the reservoir of nitrogen in the ocean from measurements and its influence on ocean fertility. Unfortunately, researchers currently employ differing techniques, causing uncertainty in whether estimates of nitrogen fixation rates are inter-comparable among research groups and among ecosystems.
Granger, Tobias and colleagues focus on the 15N2 tracer method for this study. Therein, water samples from a particular depth and region of the ocean are incubated and supplemented with isotopically-labeled nitrogen gas (15N2 gas).
Isotopes refer to the different masses an element can have depending on its atomic structure. Nitrogen can have atomic mass of 14 or 15, which are referred to as 14N or 15N. Naturally occurring nitrogen is predominantly 14N, such that adding a dollop of 15N can facilitate the tracking of nitrogen transformations.
During incubation, living diazotrophs in the water samples convert nitrogen gas (including the labeled 15N-gas) into nitrogen nutrients. At the end of the incubation, the isotopic composition (whether 14N or 15N) of the newly “fixed” nitrogen is measured. This method allows scientists to track the amount and rate of atmospheric nitrogen gas that was converted into nitrogen nutrients at a particular ocean location.
Over the years, renditions of the 15N2 tracer method have been conceived, including some with questionable practices. As not all are created equal, Granger, Tobias and co-authors ultimately recommend the so-called “dissolution” and the “bubble release” methods over others.
Additionally, Granger and Tobias stress the importance of adhering to proven mass spectrometric procedures to quantify 15N, which is crucial for obtaining representative estimates.
The paper thus states, “While the research community may remain divided as to which variant of the method to follow, the standardization of some key practices will enable intercomparability among estimates, to better discern temporal and biogeographical trends, as well as environmental controls on ocean N2 fixation.”
While both Granger and Tobias are proud of the resulting document, they agree that they will never again engage in the Herculean effort that is achieving consensus: “Herding cats is harder than science.”
Trichodesmium, a common diazotroph, blooming in the ocean. Image courtesy of NASA’s Earth Observatory image archive.
Citation:
White, A.E., Granger, J., Selden, C., Gradoville, M.R., Potts, L., Bourbonnais, A., Fulweiler, R.W., Knapp, A.N., Mohr, W., Moisander, P.H., Tobias, C.R., Caffin, M., Wilson, S.T., Benavides, M., Bonnet, S., Mulholland, M.R. and Chang, B.X. (2020), A critical review of the 15N2 tracer method to measure diazotrophic production in pelagic ecosystems. Limnol Oceanogr Methods. doi:10.1002/lom3.10353
Since the last edition of the newsletter, there has been plenty to celebrate and recognize in the department! Here you’ll find recent publications, new grants, undergraduate achievements, and awards in the Department of Marine Sciences from October 2019 through April 2020.
Awards
Description
Prof. Heidi Dierssen
Dierssen was awarded with a membership in the Connecticut Academy of Sciences and Engineering. She also was selected as team leader for the PACE (Plankton, Aerosol, Cloud, and ocean Ecosystems) NASA mission.
Prof. Peter Auster
Auster served on the Ecological Experts Working Group for development of the Long Island Sound Blue Plan. The Blue Plan is an effort to implement marine spatial planning to address conflicting human uses of Long Island Sound while conserving natural resources.
Prof. in Residence Ralph Lewis
Ralph Lewis received the Dr. Joe Webb Peoples Award from the Geological Society of Connecticut for his contributions to the understanding of Connecticut’s geology over the past 40 years.
Prof. Robert Mason
Mason became Chief Editor for the inorganic pollutants section in the new Frontiers journal Frontiers in Environmental Chemistry.
Grants
Description
Assistant Prof. Hannes Baumann
Baumann received funding by Connecticut Sea Grant to study the potential re-emergence of spawning Atlantic sturgeon in the Connecticut River in collaboration with colleagues from the Connecticut Department of Energy and Environmental Protection
Prof. Hans G. Dam
Linking eco-evolutionary dynamics of thermal adaptation and grazing in copepods from highly seasonal environments. National Science Foundation. P.I. Hans Dam. $ 531,484. 6/1/2020-5/31/2023. The grant will support a postdoc and a graduate student.
Kayla Mladinich (grad student, Prof. J. E. Ward)
Connecticut Sea Grant recently funded Kayla Mladinich and the Ward Lab to help critically examining the science of microplastics uptake by oysters.
Tyler Griffin (grad student, Prof. J. E. Ward)
Tyler Griffin received a seed grant to study the effect of chlorpyrifos, a common neurotoxic insecticide pollutant in coastal systems, on the taxonomic composition and metatranscriptomic expression of the gut microbiome of blue mussels. In collaboration with Associate Prof. Penny Vlahos.
Undergraduate Recognitions
Description
Alex Frenzel (Class of 2021)
Alexandra Frenzel just returned from her study abroad in Switzerland. An honors student as well, Alex was recently informed her 2020 SURF proposal was awarded.
Amelia Hurst (Class of 2021)
Amelia Hurst was just accepted into the NASA Airborne Science Program. Amelia was awarded University Scholar recognition this past December, the highest distinction that the University bestows on an undergraduate. Amelia is a junior seeking a double degree in Anthropology and Marine Sciences, with honors in both.
Mackenzie Blanusa (Class of 2020)
Mackenzie Blanusa was accepted into the summer 2020 Cooperative Institute for Modeling the Earth System (CIMES) Research Internship Program at Princeton University. Mackenzie is a seeking a double degree in Marine Sciences and an Individualized Major titled Atmospheric Sciences, with a minor in mathematics. She is also wrapping up her UConn Summer Undergraduate Research Fund (SURF) project.
Publications
Summary
Allison Byrd (M.S. 2019, Associate Prof. P. Vlahos)
Napolitano, Silveira, Rocha and colleagues developed a simple theoretical model to explain the recirculation of a subsurface western boundary current off Brazil. The theory agrees well with the time-mean flow observed by Argo floats and simulated with a regional numerical model. But the numerical model displays large variability due to strong westward-propagating eddies, which are not accounted for by the theory.
(On the Steadiness and Instability of the Intermediate Western Boundary Current between 24° and 18°S.)
Paradise, Rocha and colleagues employed a simple theoretical model to study the sensitivity of atmospheric blocking to climate change. Their model explores the mathematical analogy of blocking phenomena and traffic jams in freeways. The authors found that the present climate lies close to a boundary between a block-dominated state and is highly sensitive to perturbations to the jet stream.
(Blocking Statistics in a Varying Climate: Lessons from a “Traffic Jam” Model with Pseudostochastic Forcing.)
Rocha and colleagues developed new theoretical methods to characterize the strength of horizontal convection–the flow generated by differential heating at a single surface; horizontal convection is motivated by the observation that the ocean is cooled at high latitudes and heated in the tropics. Their mathematical machinery led to new bounds on the heat flux of horizontal convection.
(Improved bounds on horizontal convection.)
Chris Murray (Ph.D. 2019, Assistant Prof. H. Baumann)
Associate Prof. Julie Granger and Prof. Craig Tobias
This effort involved numerous members of the community, and resulted in a comprehensive guide to insuring inter-comparability of N2 fixation rate estimates among researchers. Granger and Tobias, as well as former lab member Lindsey Potts, contributed to this effort by providing guidelines to ensure reliable N isotope ratio analyses by mass spectrometry.
(A critical review of the 15N2 tracer method to measure diazotrophic production in pelagic ecosystems.)
Julie Pringle (M.S. 2018, Assistant Prof. H. Baumann)
Vlahos, Whitney, and colleagues found that 40% of nitrogen delivered to Long Island Sound (LIS) is primarily exported as organic nitrogen, while the rest is either buried in sediments or released as gas.
(Nitrogen budgets of the Long Island Sound estuary.)
Colleagues, family, and friends celebrated Dr. Monahan.
In the old-world tradition of a Festschrift, i.e., a celebration and book honoring the life and achievements of outstanding academics, the Department of Marine Sciences celebrated Dr. Edward C. Monahan in a full day symposium. Colleagues from Ed’s many years at UConn and Connecticut Sea Grant recounted entertaining anecdotes and his many accolades. Outside of academia, friends shared stories about his intense love for rowing crew and his involvement in local politics. One of the shining moments of the day included a photo montage of Ed’s facial hair throughout the years. Two beautiful quilts, crafted by Ed’s wife Elizabeth, were displayed throughout the festivities. One quilt captured rolling waves, the pattern being different shapes for different words for white caps. The other quilt displayed every institutional emblem in chronological order at which Dr. Monahan worked.
Dr. Monahan studied at Cornell University as an undergraduate in Engineering Physics, and continued onto his Ph.D. in Oceanography at the Massachusetts Institute of Technology, where he focused on the correlation between sea spray, whitecap coverage, and wind speed. His career brought him across the world to Ireland, where he completed another Doctorate of Science at the National University of Ireland. For two decades, he led the Connecticut Sea Grant program at UConn as its Director and initiated international marine sciences exchanges. In his retirement, Ed has not slowed down his scholarly productivity. He continues to publish scientific journal articles, remains active in the department, and stays abreast of all things oceanography by attending weekly seminars and brown bag presentations.
Dr. Penny Vlahos, chair of the symposium organizing committee, commented, “Ed and I have collaborated since I started as junior faculty. I thought it was appropriate to honor him and recognize his achievements and contributions. His work is still being cited today, especially by climate scientists in IPCC [Intergovernmental Panel on Climate Change] reports.”
Some wonderful words come from Peg Van Patten, retired communications director for Connecticut Sea Grant, “Ed Monahan was my supervisor as Director of Connecticut Sea Grant for two decades, but he was really more than that. Ed became my mentor, and friend, and sometimes my co-author. I learned so much from his experience that I was delighted when Professor Vlahos asked me to help organize a symposium in his honor. The day was a perfect tribute to Ed’s remarkable career and many accomplishments.”
Throughout the symposium, selected guests gave scientific talks on topics related to Ed’s research interests: sea spray, white caps, and air-sea interaction. Other speakers included grant recipients from Connecticut Sea Grant, collaborators, rowing partners, and students. In his retirement, Ed helped organize Coastsweek Regatta, a local rowing competition in Mystic, with 2019 marking the 28th consecutive year. At the closing of the day, attendees, family and friends enjoyed celebratory beverages and birthday cake appropriately decorated with a large wave. Allison Staniec, a current Ph.D. student who works directly with Ed, summarized the day quite well: “The Monahan Symposium (Twixt Wind and Waves) was an enjoyable celebration of Ed’s past and ongoing career with plenty of time for ground breaking science and entertaining anecdotes. And cake!”
The Festschrift book, “Recent Advances in the Study of Oceanic Whitecaps,” edited by P. Vlahos and E. C. Monahan (Honorary Editor) will be published by Springer Nature shortly.
