Organic geochemist Ann Pearson, a 1988 Orcas Island High School graduate, has been named professor of earth and planetary sciences in Harvard University’s Faculty of Arts and Sciences.
Pearson, who brings genomics, isotope geochemistry, and biochemistry to bear on the study of the Earth’s history, has been on the faculty since 2001.
In her early research, Pearson used radiocarbon analysis to tease apart the composition and origins of organic matter in marine sediment, the source of the vast majority of today’s petroleum reserves. Such “burial” of organic matter in the sea also helps control atmospheric levels of oxygen and carbon dioxide to the present day.
Despite its importance, the origin of organic matter in marine deposits was poorly understood before Pearson’s radiocarbon measurements, made during her Ph.D. work.
In a major departure from previous research, she and colleagues found that bacteria can synthesize hopanoids even in the absence of oxygen, showing that hopanoid presence alone does not establish oxidizing conditions in ancient environments.
Earlier this year, Pearson and colleagues found that a previously unknown reservoir of briny liquid buried deep beneath an Antarctic glacier supports hardy microbes that have lived in total isolation for millions of years. Despite their profound isolation, the microbes are remarkably similar to modern marine species, suggesting they are the remnants of a larger population that once occupied an open fjord or sea.
