Seagriculture Speaker

About the speaker:

Kristen Davis is an Associate Professor of Civil & Environmental Engineering at the University of California, Irvine.  She is an engineer and oceanographer who is interested in studying how physical processes shape coastal waters – combining principles of fluid mechanics, oceanography, and ecology. Kristen uses both field observations and numerical tools to examine circulation in the ocean, its natural variability, and influence on marine ecosystems and human-nature interactions. Kristen earned a Ph.D. in Civil & Environmental Engineering at Stanford University in 2009 and was a postdoctoral researcher at the Woods Hole Oceanographic Institution and the Applied Physics Laboratory at the University of Washington.  Her recent research is focused on understanding the feasibility of the large-scale, offshore cultivation of macroalgae for the production of biofuels and as a strategy to sequester carbon dioxide.

Company info: 

University of California, Irvine: https://uci.edu/

Presentation:

There is growing interest in seaweed cultivation as an environmentally regenerative form of aquaculture, a source of biofuels, and a potential strategy for carbon sequestration.  To help address questions about the expansion of seaweed cultivation we have developed a new dynamical model, the MacroAlgae Cultivation MODeling System (MACMODS), to investigate farm-scale design and siting, environmental feedbacks, as well as global-scale seaweed production potential.  At the regional scale, MACMODS integrates a regional ocean model (ROMS) with a fine-scale large eddy simulation (LES) model that resolves within-farm canopy transport and turbulent mixing and a macroalgal growth model that accounts for hydrodynamically-mediated biological processes like the enhancement of nutrient uptake due to flows and waves. We will demonstrate the utility of this framework for cultivation of giant kelp, Macrocystis pyrifera, along the California coast. At the global level, we use MACMODS alongside a technoeconomic model to address the potential productivity, costs, and potential climate benefits of seaweed farming. Here we present an interactive tool that makes the results of our work accessible. We also discuss key insights and priorities for future research.

To simulate the potential for global-scale production of both tropical and temperate seaweeds, we employ a simplified, one-dimensional form MACMODS using the vertical flux of nitrogen across the 100-m isobath from the Community Earth System Model (CESM) as a proxy for available nutrients.  We perform a comprehensive sensitivity analysis to study the impact of uncertainties surrounding biological parameters, environmental variables, and operational decisions, thus constraining estimates of total global and coastal seaweed biomass productivity.

Keywords: 

Numerical model, farm design, siting, carbon sequestration