Sack Lunch Seminar (SLS)

Abstract: A major question in how we approach climate change and its impact on the carbon cycle is at what level of granularity must we understand phytoplankton diversity. The phytoplankton that mediate CO2 uptake in the marine biosphere are tremendously diverse, non-homogeneously distributed and oftentimes physiologically ill-characterized. Additionally, they live among non-photosynthetic microbes from the three domains of life – creating a complex network of chemical exchanges and physical interactions. Microbial oceanographers frequently employ genome and environmental sequence analyses to tackle these topics, and yet many genes and features of genomes expressed in nature are of unknown function. By investigating this material in the lab and field we are discovering key, previously unidentified environmental controls and responses of phytoplankton as well as distributional information. Here, we will explore phytoplankton diversity and factors for bloom development at three levels of granularity – basic growth requirements in the context of microbial networks (in this case vitamins), evolutionary divergence (in connection to nutrient limitation), and population connectivity through deep ocean currents (using repetitive, gene-interrupting sequences). Through iterative modeling, lab, and field experiments it should be possible to test and integrate ecologically relevant levels of microbial diversity to understand primary production in transitioning ecosystems.