Time Scavengers

Joy Buongiorno Altom, Geomicrobiologist

Figure 1: My very first expedition to Svalbard for collecting mud! The Arctic is especially vulnerable to ecosystem changes with continued climate warming. To understand these changes, we head up to 79 degrees North and look at carbon-cycling microbes to gain insight into their ecological structure and function.

My love for science was born freshman year of college when I was encouraged to ask questions about nature and began reading books about the evolutionary origin of life and the cosmos. Through reading, I found that science is the best tool that we have to understand the world around us and that we should never stop asking questions of our origins. However, big questions related to evolutionary histories, for example, require the collaboration and contribution of multiple different fields of science and so, I set out on an educational journey that would allow me to grow my scientific toolbox to encompass skills across multiple disciplines. My background in zoology taught me perspective on communities and how ecological linkages between different species can play crucial roles in how an ecosystem functions. I then delved into geoscience to gain an understanding of how organisms interact with their physical and chemical environment. Now, I evaluate sediment microbial communities and their contribution to biogeochemical cycling of nutrients with genomic sequencing analyses.

Figure 2: Example of a microbial network analysis from sediment in Svalbard. Each little symbol is a different type of microorganism, and lines connecting each symbol indicates that they share either a positive (solid) or negative (dashed) relationship. Colors indicate relatedness (same colors = same family history) and different shapes indicate how they eat. These networks can help us identify novel relationships between microorganisms and generate hypotheses about what is causing a positive or negative relationship.

I am currently using my cross-discipline training to paint a complete picture of microbial communities in Arctic sediments. My goal is to make useful contributions to models aimed at describing how continued climate warming will affect carbon cycling in the Arctic Circle. It is currently unknown if the biological feedbacks associated with glacial retreat and warming surface ocean temperatures will lead to a net carbon sink (removing the greenhouse gas carbon dioxide from the atmosphere) or net source (contributing to atmospheric carbon dioxide emissions). To answer these questions, I collect environmental DNA and RNA from sediments in different fjords all over Svalbard alongside geochemistry measurements. I employ microbial network analyses to find links between community members and geochemistry to unravel the hidden drivers behind microbial abundance and community composition. With genomic sequencing data and cutting-edge bioinformatics tools, I evaluate the carbon cycling potential within nearly complete microbial genomes collected from these sediments and then computationally map their genes to RNA activity in the environment. We are finding that spatial gradients in the amount and quality of organic matter control metabolic potential of sediment microbial communities.

Figure 3: Beautiful mud core. The mud in Kongsfjorden, Svalbard is a rusty red color because of the surrounding iron-rich bedrock geology. Bands of black are where iron oxide minerals form when chemical conditions are just right. The combination of sediment accumulation and biogeochemical reactions causes this lovely tiger-striped appearance.

Pursuing a career in science has allowed me to travel the world, meet new and interesting people, experience cultures different from mine, and cultivate relationships that will prove invaluable for future collaborations. I love what I do, and encourage anyone who wants to pursue a career in science to do it! My advice to aspiring young scientists is to identify a mentor you trust early on that will guide you through tough times of self-doubt that may arise, or provide strong letters of recommendation.

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