Desert oceanographer explores tiniest of ocean plants as nature’s carbon 'pumps'

June 9, 2017

While millions of travelers will frolic on the beach during their summer vacations, most are blissfully unaware of the billions of microscopic plants making ocean life — and our lives — possible.

These microscopic creatures, known as phytoplankton, not only help support the ocean’s food chain, but also act as a vital carbon sink to buffer the ocean during eras of climate change. Phytoplankton samples Graduate student researcher Bianca Cruz holds a flask containing cultured phytoplankton. Download Full Image

This has long fascinated Arizona State University oceanographer Susanne Neuer, who wants to further explore how these plant-like microbes can help to reduce the effects of greenhouse gases like carbon dioxide, which can mix into the ocean and increase its acidity.

Small but mighty

For a new National Science Foundation-supported study, Neuer wanted to focus on some of the smallest known type of phytoplankton called Synechococcus. These single-celled, photosynthetic bacteria measure only a single micrometer wide (a millionth of a meter, or 50 times smaller than the width of a human hair).

“They are very abundant in the open ocean where there are few nutrients,” explained Neuer, who is a professor in ASU's School of Life Sciences.

Like plants, these phytoplankton use sunlight and carbon dioxide to grow. This process is called photosynthesis, and Neuer’s latest research examines how the planet’s tiniest phytoplankton play a role in permanently transporting carbon to ocean depths, a process called the “biological carbon pump."

Although marine biologists have studied these plankton organisms for decades, they still don’t know a lot about how the tiniest ones contribute to the biological carbon pump. Neuer’s recent proposal, titled “Aggregation of Marine Picoplankton,” earned a $687,521 grant award from the National Science Foundation (NSF). The grant will allow Neuer and her team an opportunity to conduct important field studies in the Sargasso Sea near Bermuda and expand their experiments at ASU.

The award is also notable because it is the first one received by the new Biodesign Center for Fundamental and Applied Microbiomics (CFAM), where Neuer is a resident researcher. The center is part of ASU’s Biodesign Institute and studies the structural mechanisms supporting communities of microscopic organisms, known as microbiomes.

According to Neuer, ancestors of today’s tiniest phytoplankton evolved around 3 billion years ago and are responsible for turning the Earth’s early atmosphere into the oxygen we breathe today.

Specifically, she’s exploring how changing water temperatures and nutrient levels are altering the way phytoplankton consume and transport carbon to the deep ocean. Those trends are becoming more concerning as climate change causes expanding “nutrient deserts” in the open ocean, according to Neuer.

Carbon sinks

The phytoplankton absorb carbon through photosynthesis, then release it as a dissolved carbon waste that can make the phytoplankton clump, or aggregate, often with other phytoplankton and bacteria, to create a shower of organic debris known as marine snow.

Neuer’s partner on her NSF grant proposal is Hinsby Cadillo-Quiroz, a fellow CFAM researcher and microbial biologist. Cadillo-Quiroz helps Neuer’s team isolate the bacteria that reside in the aggregates and investigates how they affect the phytoplankton’s aggregation.

According to Neuer’s NSF proposal, her research team discovered that low nutrient levels cause the phytoplankton to produce higher levels of clear, slimy waste known as Transparent Exopolymeric Particles (TEP). That is because they would continue to absorb carbon but if there aren’t other necessary nutrients, like nitrogen and phosphorous, then the phytoplankton just dispose of the carbon as processed waste.

More slime leads to more aggregation of plankton particles and other marine snow, which in turn increases their sinking velocity and the efficiency of the biological carbon pump.

Neuer explains, “The carbon that was fixed into the phytoplankton is now in a particle that’s heavy enough to sink out gravitationally, whereas the phytoplankton themselves are too tiny to sink. You know, they stay suspended. It’s like feathers in the air.”

World of opportunity

Neuer’s NSF grant funding will allow her team of ASU student researchers to grow more phytoplankton in their Tempe campus lab. Some of their experiments use rotating plexiglass tanks to simulate infinite sinking, while others grow different species of phytoplankton in small beakers to determine their growth and TEP formation.

They will pair their lab experiments with field studies at ocean sites around the world, including the historic Bermuda Atlantic Time-series Site (BATS), one of the longest-running oceanographic research projects in the Sargasso Sea near Bermuda. Since 1954, BATS has provided a treasure trove of oceanographic data and has documented changes in the ocean in response to climate change and increasing atmospheric carbon dioxide.

In addition to expanding knowledge about the marine planktonic microbiome, Neuer’s NSF grant also advocates for student leadership and cultural diversity amongst her research staff. The proposal highlights planned participation from students in ASU’s Microbial EducatioN Training and OutReach (MENTOR) program and School of Life Sciences Undergraduate Research (SOLUR) program, which encourages minorities in science.

One student, Bianca Cruz, is originally from Puerto Rico and now an experienced research assistant in Neuer’s lab.

“I was very interested already in marine sciences but also beyond that,” said Cruz. “How do the organisms in the ocean interact with everything else on the planet?”

Cruz is nearly finished with her master’s degree in biology, making her the first person in her family to become a scientist and the first to finish graduate school. In the fall, Cruz will continue her studies at ASU’s environmental sciences doctoral program.

While it may seem strange to conduct ocean research from the dry desert of Maricopa County, Neuer notes that parallels between the delicate balance of life in the desert and increasing “ocean deserts” from a climate change perspective.

She and her students are determined to document the importance of phytoplankton in the carbon cycle of the oceans and in warming waters, and in the process, explore Bermuda’s seas — and probably enjoy at least one beach excursion of their own along the way. 

Grace Clark

Student Assistant Science Writer, Biodesign Institute


image title

ASU Law program raises the bar for Arizona attorneys

ASU Law workshops provide continuing education for attorneys and public alike.
June 9, 2017

Continuing Legal Education courses appeal to alumni while showing the public how law and justice intersect

Lawyers know how to talk, but what if they were trained what to say?

Scientists know exactly how people think, but what if they shared that information with people who could make the most use of it, and do it persuasively?

That was the thinking behind a recent science and law seminar at the Phoenix Convention Center, one of a series of silo-busting interdisciplinary workshops hosted by Arizona State University's Sandra Day O'Connor College of Law that keeps attorneys sharp while offering the public a glimpse how law and the justice system intersects.

“ASU offers these programs to attorneys because we want to appeal to our alumni while staying connected to the lawyering community,” said Christopher G. Marohn, director of ASU Law’s Continuing Legal Education program. He added that Arizona attorneys are required to have 15 hours of continuing education credit every year by June 30, the end of their fiscal year.

Man smiling

Christopher G. Marohn

Marohn said although their programs are designed for attorneys, they are open to the public to “inform society how laws are made and to give them a better understanding of how lawyers operate in society.”

It’s a philosophy that Phoenix attorney Wendy Laskin appreciates. Laskin, a sole practitioner who specializes in mental health, probate and elder law, has attended several of these programs.

“As an attorney I can go and get credit, but it also stretches my mind as a community member,” said Laskin, who attended sessions on the Fourth Amendment, firearms and immigration, providing her “with another set of knowledge.”

This approach fits in with ASU Law’s dedication to inclusiveness and the university’s interdisciplinary approach to problem solving that has led to collaborations between business and computer science, sustainability and poetry, and science and art

The Continuing Legal Education Program hosts approximately 40 seminars, conferences, workshops, and panel discussions a year, tackling issues such as the corporatization of the prison system, design and construction, negotiation strategies, data management and emerging technologies.

Marohn, a former public defender from California, selects the curriculum, which is a mix of traditional and topical subjects.

“I pick a lot of subjects based on what’s trending in the law,” Marohn said. “Sometimes we fly off the handle and see what’s fun to do.”

That was the thinking behind “The Corporatization of Criminal Justice,” which evolved from a casual conversation Marohn had with a friend over coffee.

The April 14 conference featured civil rights leader Benjamin Jealous and tackled issues arising from the for-profit prison system, claiming it has influenced the length and severity of sentences, disproportionately harming communities of color and contributing to social inequity and oppression.

Jane Dacey, who works for the Arizona-based non-profit called Abolish Private Prisons, helped coordinate the conference with Marohn after another law school fell through. She said the free conference was attended by approximately 100 attorneys, advocates and community members, and streamed to hundreds of others online.

“The conference went over well because it featured presenters with a different perspective on mass incarceration,” Dacey said. After the conference, Dacey said she often checks with ASU’s calendar listing because “the university has so many interesting things going on.”

Two weeks later the Continuing Legal Education program hosted, “The Science of Decision Making: Persuading Judges and Jurors,” featuring national experts and Nobel Prize-winning research on human decision-making in the courtroom when presented sophisticated scientific information.

“Courtroom persuasion is all about trying to anticipate how jurors and judges will think, feel and interpret the arguments they are presenting,” said Jessica Salerno, an assistant psychology professor in the Social and Behavioral Sciences division of the New College of Interdisciplinary Arts and Sciences, and a researcher with the newly established Program on Law and Behavioral Science.

Her April 28 seminar presentation “Hot and Cold: How Decisions are Affected by Emotions and Gore,” demonstrated the emotional impact that crime-scene photos, videos and documents can have on juries, often leading to anger and a rush to judgment.

Woman smiling

Jessica Salerno

“When we have negative emotions aroused, that might lead jurors to prosecution evidence and ignore the defense,” Salerno said. “Anger and disgust can lead people to want to more punishment, longer sentences and larger damages.” She said defense attorneys could reduce the emotions of a jury by forcing verbal testimony over video, presenting photographs in black and white rather than color and showing them at the end of the trial rather than at the beginning.  

For criminal law attorney Robert J. Weber, a member of ASU Law’s inaugural class, although he enjoys the “exciting and thought-provoking curriculum,” he said it’s mostly about staying connected to his alma mater.

“Even though I graduated in 1970, I like to stay in touch with the university,” Weber said. “ASU changed my life.”

The Continuing Legal Education Program will host the Great Adverse Depositions and Attacking the Liar's "I Don't Remember" seminar on June 30 at the Beus Center for Law and Society on ASU’s Downtown Phoenix campus.