Assessing the Potential of Local Seaweed as an Agricultural Soil Amendment: Carbon, Nutrient, and Contaminant Profiling of Ulva spp. from Puget Sound

Abstract

Seaweed, often considered a nuisance in shellfish farming operations due to excessive growth and encroachment, holds untapped potential for improving agricultural soil quality as a possible valuable source of carbon and nutrients. Further research and analyses are necessary for the systematic quantification of carbon content, nutrient profiles, and presence of metals in seaweed biomass. This study developed and piloted a monitoring framework aimed at assessing the seaweed genus Ulva’s carbon and nutrient uptake capacity, with the assumption that this knowledge can provide valuable insights into its potential as a soil amendment. Ulva biomass from a commercial shellfish farms was harvested and processed for analysis of metals, carbon, and nutrients to evaluate its suitability for soil application and potential for carbon and nutrient removal from marine ecosystems. This analysis aims to deepen our understanding of the carbon and nutrient removal potential of Ulva species, with the ultimate goal of developing effective strategies for its incorporation into agricultural systems to improve soil health and crop productivity. Findings are intended to be useful to farming operations and provide valuable insights into the benefits of seaweed as a regional approach that can feasibly offer sustainable solutions using resources available within the local context.