Interdepartmental Graduate Program in Marine Science, University of California, Santa Barbara, CA, USA.
Marine Science Institute, University of California, Santa Barbara, CA, USA.
Proc Biol Sci. 2023 Nov 8;290(2010):20231817. doi: 10.1098/rspb.2023.1817. Epub 2023 Nov 1.
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) and low (0.08 g ash l) 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.
2017 年 12 月，加利福尼亚历史上最大的野火之一——托马斯大火（Thomas Fire）产生了一大片烟尘羽流，延伸到东北太平洋。在这里，我们探讨了托马斯大火灰烬沉积对海水化学以及自然微生物群落生长和组成的影响。在托马斯大火期间，在加利福尼亚沿海进行的实验表明，灰烬在海水中的浸出导致溶解营养物质（包括无机氮（硝酸盐、亚硝酸盐和铵）、硅酸、金属（铁、镍、钴和铜）、有机氮和有机碳）的显著增加。在高（0.25 克灰升）和低（0.08 克灰升）浓度下暴露于灰烬浸出液 4 天后，与未添加灰烬浸出液的群落相比，自然微生物群落的颗粒有机碳浓度高出 59%-154%。此外，丰富多样的真核微生物（原生动物）对灰烬浸出液做出了响应，与对照处理相比，来自 11 个不同分类单元的分类群的相对丰度增加。我们的研究结果表明，大型火灾事件可能是大气向沿海海洋系统输送营养物质（特别是氮）的重要来源，在那里，通过各种营养物质的浸出，灰烬可能在原生动物群落中充当“万物之食”。
