Bertagnolli Anthony D, Maritan Andrew J, Tumolo Benjamin B, Fritz Samuel F, Oakland Hayley C, Mohr Elizabeth J, Poole Geoffrey C, Albertson Lindsey K, Stewart Frank J
Department of Microbiology & Cell Biology, Montana State University, Bozeman, MT, 59717, USA.
Department of Ecology, Montana State University, Bozeman, MT, 59717, USA.
ISME Commun. 2023 Oct 17;3(1):111. doi: 10.1038/s43705-023-00315-8.
Larval net-spinning caddisflies (Hydropsychidae) function as ecosystem engineers in streams where they construct protective retreats composed of organic and inorganic material affixed with silk filtration nets that alter streambed hydrology. We hypothesized that hydropsychid bio-structures (retreats, nets) are microhabitats for microbes with oxygen-sensitive metabolisms, and therefore increase the metabolic heterogeneity of streambed microbial assemblages. Metagenomic and 16 S rRNA gene amplicon analysis of samples from a montane stream (Cherry Creek, Montana, USA) revealed that microbiomes of caddisfly bio-structures are taxonomically and functionally distinct from those of the immediately adjacent rock biofilm (~2 cm distant) and enriched in microbial taxa with established roles in denitrification, nitrification, and methane production. Genes for denitrification, high oxygen affinity terminal oxidases, hydrogenases, oxidative dissimilatory sulfite reductases, and complete ammonia oxidation are significantly enriched in caddisfly bio-structures. The results suggest a novel ecosystem engineering effect of caddisflies through the creation of low-oxygen, denitrifier-enriched niches in the stream microbiome. Facilitation of metabolic diversity in streambeds may be a largely unrecognized mechanism by which caddisflies alter whole-stream biogeochemistry.
幼虫结网石蛾（Hydropsychidae）在溪流中起着生态系统工程师的作用，它们构建由有机和无机材料组成的保护性巢穴，并附着丝质过滤网，从而改变河床水文状况。我们推测，石蛾生物结构（巢穴、网）是对氧气敏感的微生物代谢的微生境，因此增加了河床微生物群落的代谢异质性。对美国蒙大拿州一条山区溪流（樱桃溪）样本的宏基因组和16S rRNA基因扩增子分析表明，石蛾生物结构的微生物群落与紧邻的岩石生物膜（约2厘米远）的微生物群落在分类和功能上有所不同，并且富含在反硝化、硝化和甲烷生成中具有既定作用的微生物类群。反硝化、高氧亲和力末端氧化酶、氢化酶、氧化异化亚硫酸盐还原酶和完全氨氧化的基因在石蛾生物结构中显著富集。结果表明，石蛾通过在溪流微生物群落中创造低氧、富含反硝化细菌的生态位，产生了一种新的生态系统工程效应。促进河床中的代谢多样性可能是石蛾改变整个溪流生物地球化学的一个很大程度上未被认识的机制。
