Dust deposition can supply nutrients to the upper ocean, and subsequently affect primary production and biodiversity in planktonic ecosystem, but the differential response among taxa and their interactions are not fully understood. Here, we performed 7-day onboard incubation experiment amended with different dust loadings (0, 0.2 and 2 mg L-1) in the Kuroshio-Oyashio transition region of the Northwest Pacific Ocean and characterized the community structure and microbial network of a planktonic microbiome in response to dust addition. Chlorophyll a and nutrient analysis indicated that dust-derived nitrogen promoted the growth of phytoplankton (165.8–293.6%) and phytoplankton size structure shifted towards larger cells (>3 μm). Metabarcoding sequencing, targeting prokaryotic and eukaryotic microbes, revealed the changes in community structure and co-occurrence network in response to dust addition. Dust induced a shift from dinoflagellate dominance toward diatom dominance in phytoplankton, and favored members of Cercozoa, Labyrinthulomycetes and Saprospirae, which showed positive correlation with diatom. Temporal response patterns among taxa were categorized into five clusters, and collectively pointed to a more sensitive microeukaryotic community than prokaryotic one in response to dust. The community turnover during the incubation was dominated by moderate taxa with 55.71-62.26% moderate OTUs transitioning to abundant or rare taxa, and dust addition stimulated the transitions of rare taxa. Moreover, biotic factors shaped planktonic microbiome more than abiotic factors, particularly the cross-domain interaction significantly affected microeukaryotic community. Notably, dust addition enhanced the co-occurrence network complexity, with the number of keystone taxa increased, suggesting more interspecies interactions were induced by dust. With integrated analysis, our findings highlight the differential sensitivity of planktonic microbiome to dust deposition and the effects could pass on other organisms through interspecies interaction.

中文翻译：

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灰尘沉积导致西北太平洋浮游微生物群落结构和微生物网络复杂性的变化


灰尘沉积可以向上层海洋提供营养物质，从而影响浮游生态系统的初级生产和生物多样性，但类群之间的差异响应及其相互作用尚不完全清楚。在这里，我们在西北太平洋的黑潮-亲潮过渡区进行了 7 天的船上孵化实验，并修改了不同的灰尘负荷（0、0.2 和 2 mg L-1），并表征了浮游微生物组的群落结构和微生物网络。响应灰尘的添加。叶绿素a和营养分析表明，灰尘中的氮促进了浮游植物的生长（165.8-293.6%），并且浮游植物的尺寸结构向更大的细胞方向转变（>3 μm）。针对原核和真核微生物的元条形码测序揭示了群落结构和共现网络因灰尘添加而发生的变化。灰尘导致浮游植物从甲藻优势向硅藻优势转变，并有利于尾虫纲、迷宫菌纲和腐螺纲成员，与硅藻呈正相关。类群之间的时间响应模式被分为五类，它们共同表明微真核生物群落对灰尘的反应比原核生物群落更敏感。孵化期间的群落更新以中等类群为主，55.71-62.26%的中等OTU向丰富或稀有类群转变，灰尘的添加刺激了稀有类群的转变。此外，生物因素比非生物因素对浮游微生物组的影响更大，特别是跨域相互作用显着影响微真核生物群落。 值得注意的是，灰尘的添加增强了共现网络的复杂性，随着关键类群数量的增加，这表明灰尘诱导了更多的种间相互作用。通过综合分析，我们的研究结果强调了浮游微生物组对灰尘沉积的不同敏感性，并且这种影响可能通过种间相互作用传递给其他生物体。