Danish National Soil Microbiome Atlas Unveils 82% Previously Unknown Species

Danish and international researchers have successfully concluded a massive undertaking known as 'Microflora Danica,' resulting in the creation of the world's first national atlas of soil bacteria. This groundbreaking project cataloged over 140,000 distinct microbial species. Astonishingly, the findings indicate that 82 percent of these identified species were entirely new to science. This ambitious initiative drew its inspiration from the historic royal undertaking, 'Flora Danica,' which began in 1752 when botanists meticulously documented the nation's wild flora.

The comprehensive results, published in the prestigious scientific journal Nature, are the culmination of five years of intensive DNA analysis. This work was based on processing more than 10,000 soil samples gathered from diverse locations across Denmark. Professor Mads Albertsen of Aarhus University, the lead author, emphasized that this foundational research paves the way for understanding how these microscopic life forms influence vital planetary processes. These processes include maintaining water quality and regulating the absorption of greenhouse gases. 'Microflora Danica' now functions as a digital encyclopedia, allowing scientists to continuously update and expand information regarding the functions, characteristics, and interactions of these newly cataloged organisms.

The collaborative research effort involved scientists from Aarhus University, notably Professors Mads Albertsen and Per Halkjær Nielsen. Their analysis revealed that agricultural fields and urban parks hosted the highest sheer number of bacterial species. Curiously, despite the high species count in these areas heavily influenced by human activity, the species composition was surprisingly uniform. Conversely, pristine, untouched natural systems, while showing fewer species per individual sample, demonstrated a significantly higher overall level of biodiversity, often referred to as gamma diversity. This higher diversity stems from substantial differences in species makeup even across small, adjacent natural plots.

Professor Karsten Suhr Jacobsen further clarified that approximately 80 percent of the bacteria newly added to the catalog currently lack any classified ecological function. This newly acquired knowledge holds direct, practical relevance for addressing contemporary environmental challenges, particularly concerning land use management within Denmark. Microorganisms are central players in the carbon and nitrogen cycles and significantly impact the emission rates of greenhouse gases like methane. A thorough understanding of the dominant bacterial communities in specific geographic zones will enable more informed decision-making regarding the decommissioning of agricultural land for ecological restoration purposes.

The sheer volume of data compiled—encompassing 10,686 full-genome metagenomes alongside 449 datasets derived from 16S and 18S rRNA sequencing—provides an unprecedented platform for answering fundamental questions in microbial ecology. Professor Albertsen pointed out that this comprehensive overview offers opportunities to generate positive societal impact, given that microorganisms are already integral to the production of household chemicals, beer, and various food products. To honor the local origins of the discovery, more than a thousand new bacterial species were named after their collection sites, such as Hadersleviella or Rungstediana, lending a distinct local flavor to the atlas. The project intends to remain an openly accessible global database, continuing the tradition of systematic natural knowledge compilation that began in the eighteenth century.