Phytoplankton ecology & primary productivity
Phytoplankton are the base of the marine food web and hence extraordinarily important to understand from an export and climate point of view. Single-celled phytoplankton have different tricks up their sleeve than their photosynthesizing counterparts, the multicellular plants. Because they drift freely in a dynamic ocean environment, they can respond quickly to changes in conditions, and because they are single cells, many are not just primary producers, but also are capable of phagotrophy (eating; we call this dual lifestyle “mixotrophy”). Unraveling the mysteries of the phytoplankton requires many different hats, which Arianna thinks is best summed up by the ongoing debate over whether phytoplankton ecologists are “marine biologists” or “biological oceanographers”. Arianna’s primary research theme is disentangling the complex interactions between phytoplankton and the rest of the food web, and identifying the multifarous other ways that phytoplankton are affected by and have an effect on their local environment, including through toxin production, colony formation, and mixotrophy.
Exploring microbial ecology from an information science perspective
Arianna’s long-term interests in research are surveillance of microbial communities. This surveillance can provide us with a snapshot of ecosystem health in the face of ongoing dynamic change. The data science comes from Arianna’s interest in high-throughput approaches, in particular whole-community sequencing. By sequencing entire communities of microbes in situ, we can link laboratory studies of the ecology of individuals to what they’re doing in the environment. We can then identify how the genetics of communities might be changing through time, and how much variability we find both within and between species. We can encode this diversity into physiological and ecosystem models to make large-scale projections.
Ecosystem effects of microbial genetic diversity
Arianna’s likes to think of herself as a phytoplankton genealogist. She is interested in how taxonomic diversity and heredity in complex eukaryotic microorganisms affects biogeochemical cycling. To do this requires the ongoing curation of genetic resources and development of new approaches to both classify taxonomy and to identify changes in both community composition and individual lineage gene content over time. Related projects include identifying strain diversity in the globally-important coccolithophore Emiliania huxleyi, tracking the genetic effects of thermal acclimation on different strains of the same organism, and the ongoing development of software and algorithms that can be used to trace and understand environmental genetic diversity over time. A long-term grand challenge of marine microbial ecology is how to communicate our increasing knowledge of the vastness of marine microbial diversity into models that can summarize biogeochemical effects.