Professors Ballhorn, Eppley, Rosenstiel

Daniel Ballhorn (Biology) 

Plants cannot escape when attacked by herbivores and pathogens, or when exposed to unfavorable conditions, but they can defend themselves through a combination of defensive traits and ecological interactions. The Ballhorn Lab works to understand the indirect and direct defenses of plants against herbivores and pathogens, including plant biochemical defenses and microbial (bacteria and fungi) interactions.

Like humans, plants have ‘friendly’ ecosystems that live and thrive within them; complete with not only bacteria, but also fungi and more. Current research focuses on two avenues of plant defense: understanding 1) the molecular and ecological interplay of biochemical plant traits and 2) the role microbes play in helping plants to better face the changing and increasingly extreme environments they reside in. With a parallel approach of culture-based isolation and next-generation sequencing, the Ballhorn Lab utilizes gas chromatography and chemical analysis to gain a better understanding of the impact of micro communities on plant chemical phenotype and their mediation of stress tolerance and defense.

A major focus of the Ballhorn Lab is to begin to understand how to build plant systems better able to face the changing conditions of the world. In this research, among other benefits, lies the potential for the creation of Symbiotically Modified Organisms (SMO) to modify the microbiome and shift plant traits in ideal directions.


Sarah Eppley (Biology)

Plants combat various challenges during sexual reproduction, many of which mammals and other animals do not encounter. For plants, the environment itself can be the source of the strongest difficulties. The Eppley lab studies how stresses on plants in extreme environments affect their sexual reproduction, in particular that of certain bryophytes (mosses) and angiosperms (grasses, in particular). Although most plants can reproduce asexually as well, sexual reproduction has advantages for maintaining genetic diversity.

For over 20 years, Dr. Eppley has studied the effects of sea-level rise on the salt marshes on the Oregon and Washington Coasts. As sea-levels rise, salt marshes, which are an essential interface between the terrestrial and the marine coastal ecosystems, move up to higher ground. The Eppley Lab studies a species of salt marsh grass (Distichlis spicata) with separate female and male plants. The lab is interested in how the grass’ mutualistic relationship with microbes in the soil will change with the rise of salt levels and how this will affect sexual reproduction in the grass.

In Antarctica, Dr. Eppley studies how glacial retreat affects sexual reproduction in mosses. As Antarctica warms, the conditions for mosses change, actually improving the environment for sexual reproduction. Male mosses do not thrive in extremely cold temperatures, so the warming trend increases the number of male mosses in the ecosystem. The warming of Antarctica is the first time the scientists have been able to study the terrestrialization, or the retreat of the glacial ice, of an entire continent. The lab’s research contributes to knowledge about how complex ecosystems change over time in order to improve predictions about how global climate change will affect them.


Todd Rosenstiel (Biology)

Bryophytes (mosses and lichens) are quickly taking over surfaces exposed by retreating Antarctic glaciers and the biophysics of this process are increasing surface temperatures. The Rosensteil lab focuses on how the growing presence of these extremophiles shapes ecological processes and influences both local climate and biology of the atmosphere.

Working in Antarctica, Rosenstiel and colleagues seek to understand how surface warming affects the biology of terrestrial bryophytes and their associated ecological community. Reproductive spore growth from the fungi and bacteria on the bryophytes suggests that warmer conditions are favorable to increased growth. These spores (produced in the tens to hundreds of thousands) are suspected of creating more rain regionally and providing accelerated feedback, which is crucial to account for, but often missed in climate change models. The scientists also measure emissions of volatile organic compounds (VOCs) into the Antarctic environment, which are also likely produced by mosses and lichens. By studying not only bryophyte growth but also their impact on geochemistry and the biology of the atmosphere (lower troposphere), the Rosenstiel Lab aims to connect many pieces of the ever-complex climate change puzzle.

In exploring how these bryophytes are colonizing the continent of Antarctica, the research provides data for understanding their potential uses in stabilizing other planets. Having survived four mass extinction events due to their great diversity, bryophytes can survive in the most extreme of environments and are an excellent group of organisms to consider for possible answers in climate change stabilization.