Meet Maine-eDNA: Alex Ascher, Graduate Research Assistant
Jane Horovitz, EPSCoR Student Writer
Alex Ascher has always been drawn to the less understood aspects of science. So, naturally, he was interested in the marine world. Ascher sees the ocean as a black box — something that’s difficult to understand fully, but serves as a great opportunity to explore new routes of investigation. In the second year of his Ph.D. in Marine Biology at UMaine, Ascher is researching larval lobster recruitment dynamics with the Maine-eDNA program, Maine’s current NSF EPSCoR-funded Track-1 award. He is based at the Darling Marine Center (DMC) and advised by researchers Rick Wahle (UMaine Research Professor, School of Marine Sciences) and David Fields (Bigelow Laboratory for Ocean Sciences).
During a lobster’s life cycle, lobsters spend about a month as planktonic larvae after they hatch. During this time, larvae swim to the upper layers of the ocean to feed, before eventually returning to the bottom of the ocean to become full-grown lobsters.
The planktonic phase of the lobster life cycle is important in determining whether a lobster will make it to its adult phase. Ascher is interested in understanding what factors affect successful recruitment (the number of organisms that survive in a population).
“One of the hypotheses I’m looking at is that food limitation is a major constraint on larval lobsters,” Ascher says. “So potentially, the amount of food or the type of food in the environment might be one thing that [prevents] larvae from being able to survive through their larval phase.”
Lobster larvae are planktonic predators, so they consume zooplankton. Ascher will be taking water samples to survey the zooplankton present at different depths. This will help him understand what the most important zooplankton for the lobster larvae are at each depth. Because lobster larvae are so small, it can be difficult to know very basic information about them, such as what kind of zooplankton they’re specifically eating. One aspect of Ascher’s project aims to understand what their diet consists of. Ascher largely uses a method called microscopy.
Through this method, Ascher and his colleagues collect larval lobsters and examine their guts under a microscope to see what they recently consumed. However, the issue with this method is that most things inside the larvae gut are very small. They are often fractions of millimeters in size, or are small pieces of half-digested food, which are difficult to identify, Ascher explains.
“And that’s where the eDNA analysis comes in,” Ascher says. “We can take these guts and sequence them instead. We can get tons of sequences back to be able to identify what’s inside the lobster gut. Then we can corroborate what we’re seeing with the eDNA analysis with what I’m seeing under the microscope.”
Ascher started his work on larval diagnosis before the Maine-eDNA program began, but he was running into walls with his plankton identification. The Maine-eDNA program serves as a unique way for Ascher to solve some of the obstacles he faces in his research.
“I think eDNA, in general, is really up and coming. It’s where marine research is going,” Ascher says. “Since I’ve always focused on more of the whole animal, I figured it’d be great for me, as a Ph.D. student, to have a toolset for understanding how to run these smaller, more lab-based analyses.”
Ascher also enjoys the way Maine-eDNA brings together a large variety of researchers from locations across Maine, and from different fields of science and marine science.
“It’s a great way for a young grad student to be networking and meeting these people, and learning what’s going on in science right now,” Ascher says.