08.06.2026: Ocean Circulation and Climate Dynamics Colloquium

When?  Monday, 8th of June, at 16:00
Where?    Online
via Meeting link : https://geomar.webex.com/geomar-en/j.php?MTID=m6f187b689fccd196c05d249d28f6d0d8

Abstract:

The meaningful execution of marine carbon dioxide removal (mCDR) via seaweed cultivation and purposeful biomass sinking requires massive cultivated areas (~70,000 - 1 million km^2).  These scales motivate the development of modeling systems to quantify the viability of seaweed mCDR in the safety of numerical simulation.  This talk presents the development and initial application of online coupling a kelp growth model ([Mo]MAG) to the Regional Oceanic Modeling System (ROMS) and Biogeochemical Elemental Cycling (BEC) model.  The three-way, online coupling (ROMS-BEC-[Mo]MAG) simulates kelp growth in response to currents, nutrients, and light, while simultaneously resolving kelp feedbacks on these properties: nutrient uptake, exudation of dissolved organic matter, production of particulate organic matter, canopy shading, and flow damping via kelp drag.  An idealized simulation of an industrial scale, suspended kelp farm reveals complex perturbations to upper-ocean productivity and carbon cycling, both within the farm and ~1-40 km downstream.  The effects of kelp drag—flow attenuation and turbulence production—are identified as the primary control on the downstream perturbations.  These perturbations include significant impacts to the (downstream) air-sea CO2 flux.  Interestingly, the sign and spatial structure of the biogeochemical perturbations change as a function of farm placement in the equilibrated ecosystem (for example, inside or outside the phytoplankton bloom).  While model validation remains elusive due to a lack of measurements, the non-local and variable impacts of the kelp farm in the idealized experiment suggest difficulties for accurate measurement, reporting, and verification (MRV) of real-world seaweed CDR. 
 

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