1 item with the tag “carbon flux.

  • Stoichiometry of Life - Task 4 - Biogeochemical Impacts on Planetary Atmospheres
    NAI 2013 Arizona State University Annual Report

    Oxygenation of Earth’s early atmosphere must have involved an efficient mode of carbon burial. In the modern ocean, carbon export of primary production is dominated by fecal pellets and aggregates produced by the animal grazer community. But during most of Earth’s history the oceans were dominated by unicellular, bacteria-like organisms (prokaryotes) causing a substantially altered biogeochemistry. In this task, we experiment with the marine cyano-bacterium Synechococcus sp. as a model organism and test its aggregation and sinking speed as a function of nutrient (nitrogen, phosphorus, iron) limitation. So far, we have found that these minute cyanobacteria form aggregates in conditions that mimic the open ocean and can sink gravitationally in the water column. Experiments with added clay minerals (bentonite and kaolinite) that might have been present in the Proterozoic ocean show, that these can accelerate aggregate sinking.

    ROADMAP OBJECTIVES: 4.1 4.2 5.2 6.1 7.2