July 23, 2019 | 73° F

Alumna studies grass-soil interactions

Jennifer Adams Krumins, who graduated from the University’s Ecology and Evolution Ph.D. program in 2007, studied whether animal grazing can be beneficial for plants.

Krumins marked her return to campus, after conducting her 2009-2010 postdoctoral work at the Netherlands Institute of Ecology, as she led yesterday’s conference “Embracing the Good: When negative interactions turn positive in soil” in the Marine Sciences Building on Cook Campus.

Krumins concentrated her research on plant-soil feedback, including a focus on plant pathogens, diseases and their spread and growth of plant biomass, or living plant mass.

“I wanted to find a positive side to the negative interaction happening in the soil, with the thought that there has to be something positive happening in these interactions or balance could not be achieved in the ecosystem,” said Krumins, an assistant professor in the Department of Biology and Molecular Biology at Montclair State University.

She said herbivores, plant-eating animals, are inefficient consumers — don’t eat everything, and some plant material is left behind.

By approaching the issue mathematically, she proved that herbivores’ inefficiency increase the breakdown of nutrients — like soil carbon and nitrogen — for microbial uptake.

She said because of this, herbivores excrete less waste compared to omnivores.

Krumins said they excrete less because they consume less.

In the second part of her experiment, Krumins tried to prove if the intensity of grazing would benefit soil nutrients and microbial density and if it would indirectly affect plant biomass.

For this, Krumins created a greenhouse experiment in which she used sterilized dune sand and the plant “ammophila arenaria,” a species of European grass, to create her experiment.

Krumins said after measuring the system three times in a span of 149 day, she also found slight increases in species that only eat bacteria and biomass, though not conclusively.

She concluded that some direct and indirect effects of consumption by herbivores are occurring throughout her greenhouse experiment, but they are hard to observe at the trophic levels, or different positions of the food chain.

Krumins said a tree in the middle of a Netherlands national park’s visitors’ center that caught her interest and inspired a large part of her research.

“It can be seen from below the roots,” she said. “At such sight, an ecologist thinks of one thing, a habitat in [which] very interesting interactions should occur.”

Krumins said with motivation from previous ecological studies — on how seedlings are more likely to survive farther from their parent plants — she decided to study plant and soil interactions.

She said the next step is to work on looking at an increase in positive soil, overly nutrient enriched soil, when the system is in a stressful environment.

Krumins said she would start working at Liberty State Park, where the soil is highly polluted with heavy metals.

By Carmelo Cintrón Vivas

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