A Bromoform Survey Across California Coastal Seaweeds
Roman Marquez
Department of Biology
Faculty Supervisor: Zheng-Hui He
Mitigating cattle-generated methane (CH4), a significant greenhouse gas, is urgently needed. The red seaweed, Asparagopsis taxiformis (A. taxiformis), has been found to significantly reduce methane emissions in ruminant livestock when used as a feed supplement. Studies have shown that bromoform (CHBr3), produced by A. taxiformis, effectively inhibits methane production. Bromoform is biosynthesized in the hydrogen-peroxide-containing organelles, likely peroxisomes, in the seaweed. Although A. taxiformis produces high concentrations of bromoform, its cultivation presents challenges as it is a warm seawater species. We aim to investigate how bromoform is synthesized in seaweed and identify local California coastal seaweeds rich in bromoform. We hypothesize that local red seaweed species displaying prolific peroxisome morphology contain high levels of bromoform compared to their green and brown counterparts. To test this hypothesis, we took multiple approaches to characterize peroxisomes in various local seaweed species. DNA barcoding is used to identify seaweed samples collected from the local bay. Histochemical staining is applied to detect hydrogen peroxide-containing cellular structures in cryo-sectioned samples. Bromoform measurements will be conducted to understand the correlation between hydrogen peroxide staining and bromoform levels in various local seaweed species. Through these methods, we determined a consistent correlation between larger peroxisome morphology and higher concentrations of bromoform in species of red seaweed. Our study aims to provide valuable insights into how A. taxiformis and other seaweeds synthesize and sequester bromoform, paving the way to eventually identify alternative local seaweed species for potential methane mitigation in ruminant livestock.