Research Projects

Our research focuses on understanding mechanisms responsible for biogeochemical cycling in microbial ecosystems and identifying climate-ecosystem feedback loops using observations combined with numerical ecosystem models.

Life in a dynamic ocean

The oceans are inherently patchy on many different temporal and spatial scales. This variability plays a fundamental role in driving biogeochemical cycles and ecosystem dynamics. We have several ongoing projects focused on understanding the impact of fine-scale environmental variability on marine microbial communities:

  • Ocean patchiness: We are using a combination of remote-sensing data and in situ observations to quantify ocean heterogeneity, how it varies temporally spatially, and the impact on carbon cycling


  • Temporal variability: We are combining laboratory and modeling approaches to understand the impact of short-term temporal variability in environmental conditions on ecosystem dynamics.

  • Submesoscale bio-physical interactions:  We are using numerical ecosystem models to understand the impact of submesoscale variability in nutrient delivery on marine ecosystem dynamics and investigate how this may change with climate change.

Microbial ecosystem dynamics and global change

To understand ecosystem-scale response to changes in climate, we must understand the mechanisms by which individual organisms respond to the environments they experience. We have several ongoing projects aimed at developing numerical models that explicitly represent dynamic, diverse microbial communities. We are using these models to understand how marine ecosystems and carbon cycling will respond to future climates. 
  • Microbial diversity: Combining time-series data with numerical ecosystem models we are investigating the role that microbial diversity plays in biogeochemical cycling.
  • Microbial evolution: We are combining theory, empirical studies, and mechanistic models to investigate how marine microbial communities will adapt to changes in climate.

Small organisms with a large climate footprint

A large fraction of the surface ocean food web is active in producing and cycling both dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS).  In addition to the potential climatic significance of DMS production, the role that these compounds play in mediating ecosystem dynamics remains unknown. We combine measurements of functional gene abundance and expression with chemical measurements to understand the production and cycling of dimethylsulfide (DMS) at both open ocean and coastal sites.

  • Levine Laboratory
  • University of Southern California
  • 3616 Trousdale Parkway
  • Los Angeles, CA 90089-0371