Henry Holm

Postdoctoral research fellow, Columbia University's Lamont-Doherty Earth Observatory

​Bio:

Henry C. Holm is a postdoctoral research fellow at Columbia University's Lamont-Doherty Earth Observatory. After finishing his undergraduate degree at Colorado College in 2016, he began working at Woods Hole Oceanographic Institution (WHOI) as a research assistant. In 2018 he, joined Benjamin Van Mooy’s lab as a graduate student in the MIT-WHOI Joint Program in Chemical Oceanography. His doctoral work explored microbial membrane lipids in ocean environments as a tool to understanding biochemical adaptations and remineralization processes of planktonic biomass. Following his doctoral work, in 2023 he was awarded the Lamont-Doherty Earth Observatory (LDEO) Postdoctoral Fellowship. At LDEO, working with Sarah Hurley and Sonya Dyhrman, he is pursuing research to understand how future ocean CO2 and temperature conditions will affect phytoplankton growth. In 2024 he was further awarded the Center for Chemical Currencies of a Microbial Planet (C-CoMP) post-doctoral fellowship to continue this work and explore how membrane permeability may affect carbon metabolite flux.

Abstract:

Membrane lipids are a diverse pool of organic molecules that form the interface between a cell and the outside world. As such, in addition to being a key nutrient to higher trophic levels, they reveal and trace microbial responses to many kinds of environmental perturbations. In this talk, I will profile two studies that use high-resolution mass spectrometry for in-depth profiles of microbial lipids from a modern ocean environment. These lipid compositions reveal cellular adaptations to two key environmental pressures: temperature and light. The first study examines profiles of lipids from seasonal sea ice. Within the sea ice matrix, we detect a group of novel compounds that appear to be related to oxidative stress under high light conditions. These profiles additionally re-enforce sea ice as a calorically valuable pool to the Antarctic zooplankton community.  From here, I expand out to discuss a global dataset of lipids from microbes in the surface ocean. These profiles show a pronounced compositional shift across ocean basins which were well corelated to temperature. Unsaturation of fatty acids decrease with increasing temperature; a trend that was seen in every lipid class that we examined. I discuss the ubiquity of these trends in our dataset and how they represent an unavoidable adaptation to temperature. From here, I examine the abundance of poly-unsaturated fatty acids in our global dataset (a chemical group with particular trophic relevance) and forecast changes based on temperature.

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INSTAAR Seminar Series

All seminars are hybrid events, in person and via Zoom.

Audience: All are welcome

Location: Online and in SEEC S228. 4001 Discovery Drive, Boulder, CO.