Our research uses advanced microscopy and molecular methods to understand the links between microbes and their mineral habitats
Revealing & characterizing new methane sinks in the Deep Sea
At marine methane seeps, an estimated one-fifth of the planet’s methane streams out of the Earth’s crust and into seafloor sediments, representing a critical control point for an important greenhouse gas. As a metabolic by-product of the anaerobic oxidation of methane (AOM), authigenic carbonate rock precipitates, frequently leading to extensive pavements and mounds. This potentially voluminous habitat had not been previously examined as an active microbial habitat, but after an initial characterization at Hydrate Ridge, Oregon, we found the phenomenon to be pervasive at all seeps sampled to date. Current work in the lab is characterizing the microbial community and methane-oxidizing potential of sediments and carbonates from newly-discovered methane seeps off the coast of Chile.
Microbial Colonization on Minerals
Understanding where microbes are found in a certain environment and what they are doing is crucial to revealing their functions and roles in biogeochemical cycles. However, it remains unknown if microbes preferentially colonize areas with higher mineralogical complexity and if so, whether they follow certain patterns, such as associating with metal-based minerals, which may serve as electron donors or acceptors. To test the hypothesis that microbes ‘choose’ areas of higher mineralogical complexity/heterogeneity, we use confocal microscopy, Raman spectroscopy and X-Ray fluorescence spectrometry to study the mineralogical composition and biomass localization in rock-hosted microbial communities coming from two extreme environments, The Cedars in California and the Basque Lakes in British Colombia. Our results provide a general framework for understanding microbial biogeography on the microscale, informing our understanding of biogeochemical cycling and the search for life beyond Earth.
Geomicrobiology of Polymetallic Nodules
Polymetallic nodules on the abyssal seafloor are abundant, ancient substrates with high abundances of industrially relevant minerals such as cobalt, iron, and nickel. They also host prolific microbial communities, though their role in mediating nodule formation - as well as other ecologically important elemental and nutrient cycles - is poorly understood. As a part of the collaborative Dark Oxygen Research Initiative, supported by the Nippon Foundation, we will conduct metagenomic surveys, as well as in situ and lab-based stable isotope probing experiments on nodules and sediments from the Clarion-Clipperton Zone, to disentangle the role of specific microbial taxa in mediating biogeochemical cycles. With a more complete understanding of how microbes and minerals interact to form nodules and shape elemental dynamics in the abyssal ocean, researchers, companies, and policymakers will be better positioned to make sustainable decisions about our relationship with the deep sea.