ODU's Victoria Hill Helps Create 'Dylan Diatom' Cartoon Warning About Arctic Ice Melt

Dylan Diatom doesn't rank up there with SpongeBob, at least not yet, but Old Dominion University oceanographer Victoria Hill has high hopes that the cartoon character she helped to create will grab the imagination of schoolchildren all over the world.

SpongeBob, as most everyone knows, is one of the most popular cartoon characters on television and, like Dylan Diatom, his world is aquatic. These two critters are similar in other ways, too, both being no strangers to high jinks and humor.

But while SpongeBob's mission is to rake in advertising revenue, Dylan Diatom is motivated only by public service. He wants to draw attention to global warming, and specifically to global warming that is blamed for recent surges in the melting of the Arctic ice cap.

Hill (pictured), an assistant research professor, is a member of the Bio-optical Research Group in the Department of Ocean, Earth and Atmospheric Sciences at ODU. As such, she explores the relationships between the color of marine waters-for instance, as seen in satellite photos-and the biological health of the waters. Much of her research has focused on waters of the Arctic Circle, primarily the Chukchi Sea off the coast of northwest Alaska.

That's where little Dylan comes in. He-or she, or it, but more about that later-is a speck of algae drawn for a new seven-minute video as a khaki-colored disk with Mr. Potato Head-like facial features. Promotional verbiage for the video, which is called "The Important Little Life of Dylan Diatom," bills the main character as a "floating plant at the bottom of the food chain" who is "hunted by copepods, terrorized by the elements, plagued by the warming Arctic, but triumphs in this slice of life."

Diatoms have a life cycle that finds them during the dark Arctic winters drifting in nutrient-rich channels of brine that are like tiny tunnels in the ice. As the weather warms and the ice melts back, the diatoms are carried to the water's surface by the buoyancy of the fresh water from recently melted ice. This fresh water forms strata atop less buoyant salty water.

Once they are exposed to light, the diatoms multiply like crazy in so-called "blooms." As Dylan says, "I love it when I float up to the surface and can get some sun on my face." These population explosions provide plenty of food for larger critters, and also change the color of the water.

The video casts copepods as the organisms that eat diatoms. Dylan has several close brushes with these bad guys-he calls them "shrimpies that would like to eat me for breakfast"-but is saved when fish swoop in to devour the copepods.

Dylan, who cannot swim and is totally at the mercy of currents and stratification physics, also manages to survive a windy storm that drives him deep into the cold, dark water column, away from the more hospitable surface waters.

"Even a little life like mine can be very important," Dylan says in the end. "If enough of us kick the bucket because of a warming Arctic, those guys that depend on us for food, they're history."

The video was produced by the University of Washington Applied Physics Laboratory.

(See http://www.apl.washington.edu/projects/dylan_diatom/home.php.)

It was funded by a National Science Foundation grant, which had the primary aim of producing an estimate of single-cell algae production in the entire Arctic Ocean. Hill's role is to provide estimates based on NASA ocean color satellite imagery from the past decade. But other data also are being studied, some going back 55 years, to develop the estimates.

The work has been done not only by her and colleagues at the University of Washington, but also by researchers at the University of Maryland and the Bigelow Laboratory for Ocean Science in Maine. Richard Zimmerman, chair of the ODU Department of Ocean, Earth and Atmospheric Sciences and leader of the Bio-optical Research Group, also serves as a co-principal investigator on the grant.

"Phytoplankton (including diatoms) are the grass of the oceans," Hill said. "They are the start of the food chain. Zooplankton, like copepods, eat the phytoplankton and are in turn eaten themselves by progressively larger animals until we reach those charismatic mega-fauna, like polar bears, seals, walruses and whales.

"We know that the Arctic environment is changing rapidly, summer ice melt is progressively larger each year, until within maybe a decade there will be no summertime sea ice, although ice will always form during the winter. In order to understand how these changes will affect the food chain in the Arctic, we need to have a good understanding of how phytoplankton production will react."

With less sea ice formation each winter, the processes that Dylan depends upon could change. There could be more churn in the water-and less stratification-that would prevent diatoms from staying near the surface and creating intense blooms. Another possibility, according to Hill, finds rising temperatures of surface water causing a "stuck" stratification. This means Dylan and his blooming buddies would be trapped at the surface after the nutrients that they feed on are depleted, and the phytoplankton population could be drastically depleted.

"Anything that affects phytoplankton will have serious knock on effects further up the food chain," Hill said. "Taking, for example, the Chukchi Sea, this area experiences large and intense phytoplankton blooms in the spring. Much of this biomass sinks out to the seabed, as production occurs so quickly the copepods have little time to catch up. As a result of all this carbon reaching the seabed, you find huge communities of clams, sea stars, crabs, etc., which feed animals like gray whales and walruses. In turn, if these species decline you affect the apex predator, the polar bear. So, as a direct effect of changing the timing and intensity of the surface bloom, you could lose this whole ecosystem. They are already finding this happening in the Bering Sea."

Hill said "The Important Little Life of Dylan Diatom" is aimed at a middle-school audience, and that she and her colleagues would love to produce a sequel, supported by a future grant.

As for Dylan's gender, Hill calls the character "he" and "him," although "his" voice is decidedly feminine. Actually, she said, "I think we all thought that he would kind of be pretty chilled out, and so we thought of Dylan."