Dr Eric Raes1, Brent Robicheau1, Liam MacNeil1, Jennifer Tolman1, Dr. Matthias Wietz2,3, Dr. Christina Bienhold2,3, Dr. Karen Tait4, Dr. Paul Somerfield4, Dr. Andrew Bissett5, Dr. Jodie van de Kamp5, Prof. Dr. Julie LaRoche1
1Dept. of Biology, Dalhousie University, Halifax, Canada, 2Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany, 3Max Planck Institute for Marine Microbiology, Bremen, Germany , 4Marine Ecology and Biodiversity Plymouth Marine Laboratory, Plymouth , United Kingdom, 5CSIRO, Hobart, Australia
Unravelling the relationship between biological diversity and ecosystem resilience is a timeless question dating back to Alexander von Humboldt’s expeditions in the early 19th century. While global oceanographic expeditions and basin-wide transects show positive correlations between microbial diversity and temperature or productivity, they often lack temporal replication, and include few high latitude observations especially during winter months. Here, using seasonal amplicon sequence data from six time-series in the northern and southern hemispheres, we show that on a multiannual basis marine microbial alpha-diversity (species richness and evenness) correlate most strongly with day length, rather than with temperature and chlorophyll a (as proxy for primary production), independent of the targeted 16S rRNA hypervariable region.
By integrating data from 2003 to 2020, our evidence suggests that microbial diversity and annually recurring community composition are governed by similar principles, from subtropic to polar oceans. These global trends are consistent regardless of the collection methods, DNA extraction chemistry, sequencing technologies or bioinformatic pipelines. Hence, to understand drivers of marine microbial diversity, larger-scale studies need to embed their analyses into the context of regional seasonal variations. Overall, our synthesis reframes the fundamental drivers of marine bacterial diversity as phenological, and suggests that although the state of the temperature and chlorophyll spectrums should be considered, it is regular sampling over seasonal cycles that can disentangle these effects.
Biography:
I am a field and process oriented marine ecologist with expertise in end-to-end genomic analyses, biogeochemistry, and food web dynamics using isotope tracer studies. My multidisciplinary research approach has enabled me to synthesize and bridge links between the fields of microbiology, biogeochemistry and marine ecology in coastal and open oceanic environments ranging from tropical to temperate and polar environments. My research aims to provide a better understanding between different scales of biological and environmental complexity.