乐播传媒

Attending an international ocean science conference last month, Professor of Chemistry Rachel Narehood Austin emailed us to say she was 鈥渟tunned鈥� by what she was seeing.

No, the source of great wonder wasn’t her surroundings (the conference was held in Hawaii) but, as she wrote, “the impact that 乐播传媒 alumni are having at this meeting.鈥�

Held at the end of February, the is the world鈥檚 largest gathering of ocean scientists, engineers, students, educators, policy makers and other stakeholders.

Against the backdrop of global climate change, the meeting is an especially critical venue for scientific exchange among the world’s leading scientific minds.

“Be fearless”

And what’s it take to be an ocean scientist? You have to be intrepid, says Austin.

In a 乐播传媒 context, “that means we teach our students to be fearless in using whatever scientific tools, from whatever scientific disciplines,” to solve real-world questions and problems, she says.

For example, Austin said, the alumni who presented at the Ocean Science Meeting either took 乐播传媒 science courses focusing on chemical reactivity in the environment (particularly the ocean), or they did extensive work in the college’s state-of-the-art Environmental Geochemistry Laboratory, a collaborative teaching and research facility in Carnegie Science Hall.

In the end, Austin says, alumni researchers in almost any discipline are “flourishing in a world that really blurs disciplinary boundaries every day, and we encourage them to do that.”

乐播传媒 alumni at the meeting were:

• David Johnston 鈥�02, a 乐播传媒 environmental studies major who is now an associate professor at Harvard in the Department of Earth and Planetary Science.
• Erin Bertrand 鈥�05, a 乐播传媒 double major in environmental studies and chemistry who starts a tenure track position in biology at Dalhousie University in 2015.
• Kelton McMahon 鈥�05, a 乐播传媒 biology major who is a post-doctoral fellow at the University of California at Santa Cruz.
• Claire Parker 鈥�11, a 乐播传媒 chemistry major who is a Ph.D. candidate at UCSC under the noted researcher Ken Bruland.

David Johnston ’02

At Harvard, looks at how biology shaped the world billions of years ago, before the rise of atmospheric oxygen.

While his team can鈥檛 (yet) travel back in time to examine the Earth鈥檚 oxygen-free era, today鈥檚 ocean offers a 鈥渞ich and wonderful鈥� analogue of that ancient world.

Specifically, oceans have what are called 鈥渙xygen minimum zones,鈥� certain depths at which oxygen saturation is very low.

By looking at these OMZs, Johnston鈥檚 team can test their ideas about ancient Earth and, at the same time, shed light on the behavior of these systems today.

鈥淲hile many approaches to understanding OMZs rely on shipboard experiments or other indirect techniques, we have developed an in situ, or direct, way to estimate what鈥檚 happening in the OMZs.鈥�

Using isotopes of oxygen and sulfur, they鈥檙e learning more about the nitrogen and sulfur cycles within OMZs. These cycles have a direct effect on various ecosystems.

At 乐播传媒, says Johnston, a combination of 鈥渃oursework and research experiences fostered a unique perspective on how to approach a scientific problem,鈥� he says, 鈥渨hile also instilling the intellectual nimbleness that is required of interdisciplinary work. This combination has really paid dividends.鈥�

(Johnston鈥檚 path through 乐播传媒 also included a nod to the social sciences. His senior thesis used the writings of the early 20th-century to analyze the question of reintroducing wolves to the Adirondack Park in New York state.)

Erin Bertrand ’05

co-chaired a session on vitamin micronutrients and their impact on marine microbes.

She also presented findings from an experiment conducted in Antarctica鈥檚 Ross Sea in 2013, in which researchers looked at how changes in water temperature, carbon dioxide and iron availability affect phytoplankton.

Phytoplankton carry out photosynthesis, and iron, as a trace element, is necessary for this process, explains Bertrand. “This experiment will help us predict how climate change is going to impact the amount of photosynthesis happening in the Southern Ocean,” she says.

“This is particularly important because the Southern Ocean plays a large role in determining the relationship between the world’s oceans and atmospheric CO₂ concentrations,” she adds. “Change in Antarctic phytoplankton growth in response to a warming ocean has the potential to profoundly influence that relationship.”

When she starts her position at Dalhousie, Bertrand will be nominated for a Canadian Research Chair, a $300 million Canadian program to attract and retain the world鈥檚 most accomplished and promising minds.

Kelton McMahon ’05

At the Ocean Sciences meeting, organized and co-chaired a major session on 鈥渃ompound-specific stable isotope analysis,鈥� or CSIA.

In terms of understanding ecosystems, this powerful, relatively new tool can analyze an organism鈥檚 isotopic 鈥渇ingerprint,鈥� which in turn tells about its life and times, its place in the food web and where it鈥檚 been.

McMahon鈥檚 research has looked at long-term isotope data from deep-sea corals in the North Pacific Ocean that have lived 鈥渁n incredibly long time, over 2,000 years.鈥�

He says that since the end of the Little Ice Age around 1850, there appears to have been a 鈥渇undamental shift鈥� in the ecosystem鈥檚 biogeochemistry. Like so much of what affects the environment on a large scale, the reason for the shift might relate to something very small, in this case, microscopic organisms known as phytoplankton.

In the North Pacific Ocean, McMahon and his coauthors have seen a 鈥渄ynamic change鈥� in the composition of the phytoplankton community, from one that was dominantly eukaryotic (cells have a nucleus) to one that is now prokaryotic (cells don鈥檛 have a nucleus).

鈥淥ur results provide an unprecedented historical context for the dramatic recent changes in Pacific Ocean biogeochemistry,鈥� he says.

The findings, he adds, could also change how scientists think about the North Pacific subtropical 鈥済yre,鈥� or ocean current movement. Because these currents are a 鈥渃ritical regulator of global CO2 and biogeochemical balance,鈥� any change in phytoplankton communities could alter that critical function.

Claire Parker ’11

gave what Austin called a 鈥渨onderful talk鈥� on three metals 鈥� scandium, yttrium and lanthanum 鈥� and their distributions in the ocean. Her thesis adviser, Ken Bruland, is an expert in the interaction of trace metals with biotic (living) and abiotic (nonliving) aquatic ecosystems.

Parker鈥檚 work is part of the project, an international effort to measure the concentrations of trace metals throughout the world ocean in order to better understand key biological, chemical, and physical processes.

Parker enjoys her work because there鈥檚 no limit to where the study of trace metals might take her.

鈥淪tudying trace metals is surprisingly applicable to almost everything else in the ocean.鈥�

For example, some metals are necessary nutrients for plants, and plants are at the base of the ocean food chain.

Some pollutants can be tracked with trace metals. And undersea hydrothermal vents release 鈥渉uge concentrations of many metals in a plume that can be detected a thousand miles away.鈥�