The Role of Phytoplankton in a Changing Planet

We are a biological oceanography group at the University of Washington, studying how phytoplankton, the microscopic photosynthetic organisms that support ocean life and help regulate Earth’s climate, respond as the ocean warms. We use automated instruments like SeaFlow, our shipboard flow cytometer, to track these communities across thousands of miles of open ocean. We then combine these measurements with statistical and machine learning methods to test what controls their growth and survival.

High-Resolution Ocean Observations

We use our custom-built SeaFlow flow cytometer to collect continuous, real-time observations of phytoplankton at sea. The instrument measures the size and fluorescence of individual cells every kilometer, capturing the fine-scale ecosystem structure that underlies larger patterns in ocean productivity and carbon cycling. Over the last decade, this automated system has analyzed more than 800 billion cells during nearly six global circumnavigations, revealing rapid shifts and small-scale processes that shape ecosystem dynamics across ocean basins.

Statistical Tools and Population Models

We use statistical models to extract biological insights from SeaFlow data. We develop population models to estimate key rates - such as growth, division and mortality - from the spatial and temporal changes in phytoplankton size distributions. By linking these rates to environmental conditions, we show how factors like temperature, nutrients, and light shape phytoplankton communities on a global scale.