Nicole Coots, a PhD student in her third year of evolutionary biology research at Arizona State University, is smitten by radiolarians, drifting plankton known for their complex, beautifully-sculpted miniature skeletons they make from minerals in ocean water. Like snowflakes, they seem to exist in almost unlimited variety. They are also key members of the food web throughout the surface waters of the global ocean, providing nutrition for other sea life.
Despite their important role in marine ecosystem dynamics, some aspects of radiolarians are largely understudied. Radiolarians have the unique ability to house microalgae within their own body, where they provide the radiolarian with life-giving sugar byproducts of photosynthesis, a process known as endosymbiosis. Coots’s work at BIOS will help to pinpoint the identity of the endosymbionts through her genetics and microscopy work, a focus of her research in Arizona.
With support this spring from Grant in Aid (GIA) funding at BIOS, Coots and her BIOS mentor Leocadio Blanco-Bercial will perform a survey of radiolarian photosymbiont diversity in the Sargasso Sea. “I hope to expand our knowledge about how an important group of marine plankton are capable of a unique endosymbiotic relationship that generates nutrients in parts of the ocean that would otherwise be nutrient depleted,” she said.
Coots, 25, was among the first of seven students and researchers to arrive at BIOS for research and study supported in part with GIA funds, which provide start-up allowances up to $4,000 on projects that may lead to continuing and ongoing research efforts at BIOS. The program supports projects involving collaboration with BIOS scientists and helps to defray costs such as small boat rental, boat fuel, diving tank fills, lab fees, access to specialized equipment such as microscopes, accommodation, and dining hall meals.
Coots came to BIOS in May with the single-minded pursuit of gathering about 100 single radiolarians from plankton samples near Bermuda. It is no small feat given how finicky and delicate they are; all of her research has to be based on living, freshly-caught samples.
“My particular study organism is even more challenging to work with because it is fragile and can be somewhat elusive, even in areas of the ocean where we know they are most abundant,” she said.
She spends hours on small boats offshore Bermuda collecting samples with a net from the surface down to about 500 feet (150 meters) depth, where surface light begins to fade, then isolating and imaging radiolarians from samples using a glass pipette and microscope.
“It’s extremely rewarding to find them in my samples because they occur so infrequently,” she said. “They’re really beautiful cells, and every time I find one I get really excited. They’re especially cool to find when they’re alive because you can see the movement of the arm-like protrusions of the cell that they extend outward into the water, searching for food. It’s totally awesome.”
Once located, the organisms will return with her in June to ASU, where she will extract, sequence, and analyze their genetic material for use with the remainder of her PhD work.
Some GIA recipients, like Moriah Kunes of Princeton University in New Jersey, will be on campus for just a few weeks for research and mentoring under the guidance of BIOS faculty and staff members. Others will stay for as long as two months, including Tiburon Benavides of Rensselaer Polytechnic Institute in New York and Elizabeth Brenna of Oregon State University. Additional participating students include Shalimar Moreno of East Carolina University in North Carolina and Rodney Staggers of Arizona State University. Climatologist Hans Christian Steen-Larsen, an adjunct scientist at BIOS and a GIA recipient, conducts his research at the University of Bergen in Norway.
In addition to Blanco-Bercial, other BIOS faculty and staff members working with GIA recipients this year include Damian Grundle, Kaitlin Noyes, Rachel Parsons, Andrew Peters, and Yvonne Sawall.
For the grant recipients and their mentors, there is ample opportunity for mutual exchange of ideas. For marine ecologist Blanco-Bercial, Coots’s enthusiasm and knowledge of these primarily microscopic, single-celled marine organisms, also called protists, is especially appreciated as he begins to expand his own zooplankton studies into the protist arena.
“I welcome her A LOT,” he wrote in an email, “since this collaboration might easily speed up my own research. Our plan will be to have her back here next year, so she can gather more data and we can keep moving research manuscripts forward together.”