Optimizing bromoform content in Gracilaria parvispora: the role of environmental stressors

Publication Date

1-1-2025

Document Type

Article

Publication Title

Journal of Applied Phycology

DOI

10.1007/s10811-025-03602-0

Abstract

Methane (CH4) emissions from ruminant livestock significantly contribute to global anthropogenic greenhouse gas emissions. Innovative approaches to mitigate these emissions are crucial for sustainable agricultural practices. One potential mitigation method under investigation involves using feed additives to reduce enteric methane production. Seaweeds, particularly of the genus Asparagopsis, have shown remarkable efficacy in mitigating methane emissions due to their high bromoform content. However, challenges in scaling the production of Asparagopsis spp. cultivation are currently hindering its widespread commercial adoption. This study explores an alternative red seaweed, Gracilaria parvispora cultivated globally at industrial scales, for its bromoform synthesis and emission rate. Specifically, this study investigates methods to enhance bromoform production in G. parvispora utilizing environmental stressors, including desiccation, increased temperature, and changes in light intensity in a land-based aquaculture facility. By examining how bromoform content and emissions vary over diel cycles and under distinct stress conditions, we clarify the temporal dynamics of bromoform synthesis and loss—revealing, for instance, midday surges followed by rapid declines and divergent effects on tissue content versus emissions. We found that G. parvispora bromoform content varied significantly with light intensity, surging over 300% from sunrise to midday during peak light intensity, but declining rapidly by sunset. Desiccation stress boosted bromoform tissue concentration by 63%, while temperature stress increased emissions by 49.5%. Based on these findings, we outline practical cultivation and harvest methods to enhance bromoform content: cultivate in direct sunlight (PPFD between 1000 and 1500) to promote bromoform production, maintain cooler waters (< 21 °C) to prevent bromoform loss via volatilization, harvest during peak solar irradiance, and allow for brief desiccation (< 1 h) in direct light before or during harvest.

Funding Sponsor

Anthropocene Institute

Keywords

Aquaculture, Bromoform content, Bromoform emissions, Gracilaria, Halogenated metabolites, Physiology, Rhodophyta

Department

Moss Landing Marine Laboratories

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