Learning from the Past to Understand the Future of Ocean Ecosystems

Biology/Earth and Planetary Sciences

Sedimentary rocks provide a record of the intertwined histories of life and environment that is reflected in the genomes of organisms alive today. This proposal is aimed at combining genomics with the biogeochemical history of photosynthetic life on Earth to learn more about the two-way interactions between climate and evolution. The work will be focused on diatoms, marine photosynthetic microbes that today perform around 20 percent of primary production on Earth. The rich diatom fossil record will show how they have affected and have been affected by changes in climate during Earth's history, and analysis of ancient DNA will reveal how their genomes have changed through time. Changes in morphology and cell size over geological time will be compared with information from the Tara Oceans project about extant diatoms in the contemporary global ocean to reveal how the environment affects these processes to improve understanding of how diatom communities will be affected by climate change in the future ocean. As a key component in marine food webs and the carbon cycle, learning how diatoms have been affected by the environment in the past will be central for predicting the future characteristics of ocean ecosystems.

My work with a research partner will focus on two separate projects: 1) Based on the extensive fossil records, the research partner will study the rise and fall of diatom abundance and diversity in the past and will relate it to living diatoms in today’s oceans. Most efforts will be focused on the last 50,000 years. 2) Techniques will be developed to sequence ancient DNA from diatom-rich cores covering the last 50,000 years collected from the seafloor. Sequences will be dated and compared with the genomes of extant diatoms to learn about how diatoms have adapted to climate changes in the past. Both genetic and epigenetic changes will be assessed.

The project will become a group effort, and so will advance more efficiently. It will additionally benefit from multiple intellectual inputs. The research partner will benefit from a cross-disciplinary research project incorporating the latest knowledge from the geosciences and cutting-edge techniques in genomics and microbial oceanography. By bringing together genomic and morphological information from extant diatoms with knowledge from ancient DNA and the fossil record, I believe that a new understanding can be reached about the relationships between diatoms and climate that will be highly informative for being able to predict their adaptations in a future ocean modified by climate change.