2023-12-04 カリフォルニア大学サンタバーバラ校(UCSB)
◆この結果は、火山灰が淡水生態系でしばしば有毒であるのとは対照的であり、火山灰が海洋生態系において有益な影響を及ぼすことを示唆しています。
◆研究者たちは山火事の影響を海洋生態系に調査するために急遽研究クルーズを計画し、火山灰が海洋に与える影響に初めての洞察を得ました。海洋では火山灰が淡水よりも希釈されるため、有害な影響は見られなかったとされています。今後、山火事が変化する中で、陸地から海洋への栄養とエネルギーの転送に対する注意が必要とされます。
＜関連情報＞
- https://news.ucsb.edu/2023/021283/thomas-fire-research-reveals-ash-can-fertilize-oceans
- https://royalsocietypublishing.org/doi/10.1098/rspb.2023.1817
すべての人に食料を？山火事の灰が多様な真核プランクトンの成長を促進 Food for all? Wildfire ash fuels growth of diverse eukaryotic plankton
T. M. Ladd,D. Catlett,M. A. Maniscalco,S. M. Kim,R. L. Kelly,S. G. John,C. A. CarlsonandM. D. Iglesias-Rodríguez
Proceedings of the Royal Society B Published:01 November 2023
DOI:https://doi.org/10.1098/rspb.2023.1817
Abstract
In December 2017, one of the largest wildfires in California history, the Thomas Fire, created a large smoke and ash plume that extended over the northeastern Pacific Ocean. Here, we explore the impact of Thomas Fire ash deposition on seawater chemistry and the growth and composition of natural microbial communities. Experiments conducted in coastal California waters during the Thomas Fire revealed that leaching of ash in seawater resulted in significant additions of dissolved nutrients including inorganic nitrogen (nitrate, nitrite and ammonium), silicic acid, metals (iron, nickel, cobalt and copper), organic nitrogen and organic carbon. After exposure to ash leachate at high (0.25 g ash l−1) and low (0.08 g ash l−1) concentrations for 4 days, natural microbial communities had 59–154% higher particulate organic carbon concentrations than communities without ash leachate additions. Additionally, a diverse assemblage of eukaryotic microbes (protists) responded to the ash leachate with taxa from 11 different taxonomic divisions increasing in relative abundance compared with control treatments. Our results suggest that large fire events can be important atmospheric sources of nutrients (particularly nitrogen) to coastal marine systems, where, through leaching of various nutrients, ash may act as a ‘food for all’ in protist communities.
