Comparative nutrient drawdown capacities of farmed kelps and implications of metabolic strategy and nutrient source

Journal Article · 28 March 2024 · Journal of Phycology

DOI: https://doi.org/10.1111/jpy.13442 · OSTI ID:2371728

Stephens, Tiffany  ^[1]; Umanzor, Schery ^[1]

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1. College of Fisheries and Ocean Sciences University of Alaska Fairbanks Juneau Alaska USA

Abstract Seaweed aquaculture, particularly kelp farming, is a popular topic as a potential solution for mitigating anthropogenic pollutants and enhancing coastal drawdown of carbon and nitrogen. Using a common garden approach, this study evaluated nutrient drawdown capacities of Alaria marginata (ribbon kelp) and Saccharina latissima (sugar kelp) across four commercial kelp farms in Southeast and Southcentral Alaska. Our findings show that A. marginata exhibited ~30% more carbon and 21% more nitrogen content compared to S. latissima . These results demonstrate the potential for A. marginata to serve as a more efficient species for nutrient drawdown into farmed kelp tissues (per unit biomass) for consideration of potential mitigative actions. The efficacy of this drawdown is likely to be driven by the careful pairing of kelp species with farming environment. Temporally, there was a noted increase in carbon content and a decline in nitrogen content from March to May for both species, consistent with known seasonal nutrient dynamics in coastal waters. Notably, differences in the carbon stable isotope signatures (δ ¹³ C) between the kelps may hint at variations in metabolic pathways and nutrient sourcing, particularly concerning the preferential assimilation of CO ₂ versus , and highlight the need for further work on this topic for applied macroalgal research.

• Sponsoring Organization: USDOE
• OSTI ID: 2371728
• Journal Information: Journal of Phycology, Journal Name: Journal of Phycology Journal Issue: 3 Vol. 60; ISSN 0022-3646
• Publisher: Wiley-BlackwellCopyright Statement
• Country of Publication: United States
• Language: English