Event

On Monday, April 17th, Professors Martyn Tranter and Alex Anesio will be visiting the Penn BiCycles Lab. The two will be presenting a seminar from 12:00-1:00 PM in Hayden Hall room 358. 

“How microbes melt glaciers and ice sheets”

Glaciers and ice sheets were long believed to be sterile environments, but just like other large ecosystems (e.g., tropical forests, tundra), they are now widely recognized as one of the Earth’s biomes, teeming with life. This biome is also the most under-investigated on the planet from a biological and biogeochemical perspective, representing a new and exciting frontier in science. Home to large, naturally occurring communities of mostly microbes, glaciers and ice sheets host metabolically active organisms, interacting with each other. These processes represent more than just a minor curiosity of life under extreme conditions. On glacier and ice sheet surfaces, microbes have been shown to alter physical and chemical characteristics of snow and ice with direct consequences for snow/ice solar-heating and amplified melt. During the summer ablation, the bare ice is largely dark, as it is colonized by pigmented ice algae. Biological growth of icebound algal cells can accumulate biomass high enough to cause albedo reduction between 12% and 21%, depending on the algal cell abundances. In this talk, we will discuss how pigmented algae, growing directly on the snow and bare ice, have a crucial role in changing the reflectivity of the ice (i.e., albedo), and subsequently the melt rates of the ice. We will discuss the biology, microbial interactions and the main bottom-up and top-down controls of glacier ice and snow algae.

Prof. Alexandre Anesio

Professor in Arctic Microbiology

Department of Environmental Science

Aarhus University, Denmark

Alexandre Anesio is a Professor in Arctic Microbiology in the Department of Environmental Science at Aarhus University. His main research interest is on microbial and biogeochemical processes in glaciers and ice sheets. He is currently one of the PIs in a European Research Council Synergy grant to investigate the biological darkening of the Greenland ice sheet. Anesio obtained his PhD degree at Lund University in Sweden in 2000, where he also worked as postdoc until 2003. Since then, he has worked at the University of Nottingham (2003-2004), Aberystwyth University (2004-2007) and University of Bristol (2007-2018), until moving to Denmark in 2018.

Prof. Martyn Tranter

Professor in Polar Biogeochemistry

Department of Environmental Science

Aarhus University, Denmark

Martyn Tranter is a Professor in Polar Biogeochemistry in the Department of Environmental Science at Aarhus University. His main research interest is microbially mediated chemical weathering on, in and under glaciers and ice sheets. He is also currently one of the PIs on a European Research Council Synergy grant to investigate the biological darkening of the Greenland ice sheet. Tranter obtained his PhD in Environmental Sciences, UEA (UK) in 1982, where he also worked as postdoc and temporary lecturer until 1986. He moved to Oceanography at Southampton (UK) in 1986, and then to Geography at Bristol in 1992. He has worked at Aarhus since 2020.