The triple oxygen isotope composition of marine sulfate and 130 million years of microbial control.

The triple oxygen isotope composition (Δ'O) of sulfate minerals is widely used to constrain ancient atmospheric O/CO and rates of gross primary production. The utility of this tool is based on a model that sulfate oxygen carries an isotope fingerprint of tropospheric O incorporated through oxidative weathering of reduced sulfur minerals, particularly pyrite. Work to date has targeted Proterozoic environments (2.

Volcanic controls on seawater sulfate over the past 120 million years.

Changes in the geological sulfur cycle are inferred from the sulfur isotopic composition of marine barite. The structure of the S/S record from the Mesozoic to present, which includes ∼50- and 100-Ma stepwise increases, has been interpreted as the result of microbial isotope effects or abrupt changes to tectonics and associated pyrite burial. Untangling the physical processes that govern the marine sulfur cycle and associated isotopic change is critical to understanding how climate, atmospheric oxygenation, and marine ecology have coevolved over geologic time.

Metabolic Capability and Phylogenetic Diversity of Mono Lake during a Bloom of the Eukaryotic Phototroph Picocystis sp. Strain ML.

Algal blooms in lakes are often associated with anthropogenic eutrophication; however, they can occur without the human introduction of nutrients to a lake. A rare bloom of the alga sp. strain ML occurred in the spring of 2016 at Mono Lake, a hyperalkaline lake in California, which was also at the apex of a multiyear-long drought.