Fundamental research questions in subterranean biology

Five decades ago, a landmark paper in Science titled The Cave Environment heralded caves as ideal natural experimental laboratories in which to develop and address general questions in geology, ecology, biogeography, and evolutionary biology. Although the 'caves as laboratory' paradigm has since been advocated by subterranean biologists, there are few examples of studies that successfully translated their results into general principles. The contemporary era of big data, modelling tools, and revolutionary advances in genetics and (meta)genomics provides an opportunity to revisit unresolved questions and challenges, as well as examine promising new avenues of research in subterranean biology. Accordingly, we have developed a roadmap to guide future research endeavours in subterranean biology by adapting a well-established methodology of 'horizon scanning' to identify the highest priority research questions across six subject areas. Based on the expert opinion of 30 scientists from around the globe with complementary expertise and of different academic ages, we assembled an initial list of 258 fundamental questions concentrating on macroecology and microbial ecology, adaptation, evolution, and conservation. Subsequently, through online surveys, 130 subterranean biologists with various backgrounds assisted us in reducing our list to 50 top-priority questions. These research questions are broad in scope and ready to be addressed in the next decade. We believe this exercise will stimulate research towards a deeper understanding of subterranean biology and foster hypothesis-driven studies likely to resonate broadly from the traditional boundaries of this field. S.M acknowledge support by the CAWEB project “Testing macroecological theory using simplified systems”, funded by the European Commission through Horizon 2020 Marie Skłodowska-Curie Actions (MSCA) individual fellowships (Grant no. 882221). I.R.A. was supported by Portuguese funds through FCT – Fundação para a Ciência e a Tecnologia, I.P., under the Norma Transitória – DL57/2016/ CP1375/CT0003. D.E. was supported by IFREMER and by the CERES “Climate change and European Aquatic Resources” project funded by European Commission through Horizon 2020 research and innovation programme (Grant no. 678193). C.F., Z.F., and M.Z. were supported by the Slovenian Research Agency (program P1-0184, project N1-0069). J.E.K. was funded by NSF awards DEB1754231 and IOS1933428, and EDGE award 1923372. F.M. was supported by the French National Research Agency projects CONVERGENOMICS (ANR-15-CE32-0005) and EUR H2O’Lyon (ANR-17-EURE-0018). A.M. was supported by the ANCAVE project “Anchialine caves to understand evolutionary processes”, funded by the European Commission through Horizon 2020 Marie Skłodowska-Curie Actions (MSCA) individual fellowships (Grant no. 745530). P.A.V.B. was supported by the project AZORESBIOPORTAL – PORBIOTA (ACORES-01-0145-FEDER-000072), financed by FEDER in 85% and by Azorean Public funds by 15% through Operational Program Azores 2020. A.S.P.S.R. was supported by VILLUM FONDEN (Grant no. 15471) and by a Carlsbergfondet grant (CF19-0609). T.G.P. was supported by Vale S.A. and Fundação de Amparo à Pesquisa de Minas Gerais (FAPEMIG) for individual fellowship (RDP 00092-18). T.P. was supported by the Karst Research Programme P6-0119, LifeWatch ERIC, RI-SI LifeWatch, and EU H2020 project eLTER. info:eu-repo/semantics/publishedVersion