Taxonomy and natural history of freshwater meiofauna: classical and contemporary expertise-sharing in a field workshop setting

The meiofauna constitutes the microscopic, aquatic invertebrates and protists of <1 mm size, such as nematodes, tardigrades, and rotifers, which can be found ubiquitously in sediments and on aquatic plants. Research activity on these communities, which are crucial to the transfer of energy and materials between the microbial and visible worlds, is disproportionately low relative to their considerable species diversity and unparalleled phylogenetic diversity. Indeed, the sheer magnitude of this diversity, and the requirement for careful microscopical study for proper identification, has limited the taxonomic attention on these creatures. Hence, if ecological and applied studies consider meiofauna at all, it is typically only a few exemplar taxa that are recorded, and only to a limited taxonomic resolution, such as family or order. DNA-based taxonomy stands to revolutionize this status quo, but with experienced taxonomists in demographic decline, the window to populate sequence databases with well-determined references assigned to Linnean taxa is closing. In marine settings, a powerful initiative to counter this inertia has been the establishment of "all-taxon meiofauna workshops", in which early career scientists are paired with established taxonomic experts covering most or all meiobenthic taxa in a biodiverse field setting. Such workshops are vital to perpetuating practical natural history and taxonomic knowledge of these overlooked creatures, and often become seminal experiences for all participants, germinating enduring collaboration networks and new research directions. This proposal will fund, to our knowledge, the first such taxonomic workshop focused on freshwater meiofauna, intended to support the next generation of ecologists and systematists. Set in the Lake District over two weeks in early autumn, we will cover field techniques for sampling soils/mosses, standing and running waters, and groundwater. In our fieldwork, especially in globally significant temperate rainforests, we will explore a theme of how human land use and climate change may affect meiofauna. Each of 13 taxonomists, many of whom represent globally prominent experts, will teach the fundamental biology and natural history of their animals, with a pragmatic focus on the microscopical techniques and morphological characters that are needed for identification, and a review of the most important literature and database resources. The core of the workshop, representing ~40% of our time, is the practical study of living specimens, during which students will also have opportunities to practice advanced microscopical techniques and digital microphotography & videography. In this practical segment, taxon experts will also populate an inventory, preserving as many well-determined specimens as possible for genomic study at the Sanger Institute’s Darwin Tree of Life initiative. We will consolidate our activities with a capstone project in which all participants are challenged to "adopt" a species, identifying it with a Linnean name if possible, and presenting the details of its natural history and taxonomy for both specialist and public audiences - which latter will be addressed in a short social media video recorded on site. Finally, and with all taxon experts joining as students as well, we will test the coherence of the participants' species by conducting an in-field nanopore sequencing project, in which DNA barcodes are collected from many digitally photo-vouchered representatives of each adopted species. We will then demonstrate species delimitation techniques on the students' own data, and consider the implications (e.g. the presence of cryptic species, or overlooked diagnostic characters consilient with the molecular results), closing the hypothesis-testing cycle.