Macroalgae

Macroalgae is a potentially valuable energy resource, but significant advances in its domestication and farming technologies are needed to increase productivity and support a seaweed-to-fuels industry. The development of advanced modeling tools can help understand the nature of macroalgae production, as well as reduce deployment costs, operational risk, and potential impacts on the marine environment.

 

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Left panel: a hypothetical tidal farm simulation in Saco Bay showing the impact of kelp farms in nitrate uptake; Middle panel: global nitrate field simulated by Los Alamas National Laboratory’s MPAS-O model. Right panel: sugar kelp farm in Hood Canal.

 

Projects

Multiresolution, Multiscale Modeling for Scalable Macroalgae Production  

Successful deployment of large-scale marine macroalgae farms for fuel production strongly depends on not only innovative designs of cultivation and harvesting systems, but also on ambient hydrodynamic and nutrient conditions.  This project developed a set of coupled models to simulate macroalgae growth, nutrient uptake and structure-hydrodynamic interactions using a multi-resolution, multiscale modeling framework.

illustration of wind, waves and currents
(Left panel) Framework of the modeling approach; (Center panel) A conceptual diagram of the macroalgal growth model framework depicting the major forcing processes driving the macroalgae transport and growth in the coastal ocean; (Right panel) Predicted floating trajectory and biomass distribution for a hypothetical floating kelp farm on the U.S. West Coast

 

 

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The framework of the operational forecast system for Sagarssum trajectory and biomass prediction.

Ocean Energy from Macroalgae. 

Sargassum is an ideal species to achieve DOE’s goal for large-scale production. Its free-floating nature reduces costs, seeding, and farm equipment normally associated with traditional mariculture. Led by Fearless Fund, this project seeks to mitigate the damage of large-scale Sargassum beachings and repurpose the biomass through optimized harvest for energy and economic uses. The Ocean Dynamics Modeling group supports the project by developing a Sargassum forecast system to predict the trajectory and biomass growth of Sargassum in the tropical region.

 

 

 

 

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Synethtic hurricane tracks (provided by Prof. Kerry Emunual of MIT) passing through the proposed project in Puerto Rico. The synethtic hurricane tracks are being used to generate hurricane wind fields to drive the hurricane-induced storm surge and large wave simulations.

The Development of Techniques for Tropical Seaweed Cultivation and Development.

In this project, the PNNL team will develop a high-resolution coupled wave and storm surge model for the proposed project sites in Puerto Rico and West Florida. Model results from the storm surge and wave model, together with the CariCOOS hydrodynamic model, will be used to support the hydrodynamic load modeling and the fine-scale LES/macroalgae simulations at the project sites. A methodology will be developed to assess the threshold current distribution induced by hurricanes passing through the project sites.

 

 

 

 

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(Upper panel ) The proposed study site and approach and (bottom panel) Snapshots of model- predicted nitrate (a) and current (b) field near Hood Canal Kelp Farm to demonstrate the farm's impact. The results were produced based on a much simplified model configuration and are for demonstration purpose only.

Quantifying Nitrogen Bioextraction by Seaweed Farms – A Real-time Modeling-Monitoring Case Study in Hood Canal, WA

In this project, the research team is conducting an integrated numerical modeling and field monitoring study at the Hood Canal Kelp Farm in Washington, to quantify the rate and effectiveness of nitrogen bioextraction by the kelp farm. A coupled hydrodynamics-macroalgal growth model will be used to simulate kelp growth, nutrient uptake, and the physical interaction between kelp and ambient currents at a meter-level spatial resolution.