A Test in a High Altitude Lake of a Multi-Parametric Rapid Methodology for Assessing Life in Liquid Environments on Planetary Bodies: A Potential New Freshwater Polychaete Tubeworm Community

Frontiers in Environmental Science

Enrique Moreno-Ostos¹  Fabián A. Figueroa²  Cecilia Demergasso³  Cristian Tambley⁴  Julie Robidart⁵  Eric W. Smith⁶  Pablo Sobrón⁶  Ignacio Gallardo-Carreño⁸  Victor Parro⁸  Alberto G. Fairén⁹  Virginie C. Tilot^1,11  Nieves Lopez-Gonzalez^1,11  Rupert F. G. Ormond^1,12  Nathalie A. Cabrol^1,14 

[1] 0Department of Ecology and Geology, University of Málaga, Málaga, Spain;1Laboratorio de Química de Productos Naturales, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Concepción, Chile;2Centro de Biotecnología, Universidad Católica de Norte, Antofagasta, Chile;3Campoalto Operaciones SpA, Santiago, Chile;4Ocean Technology and Engineering, National Oceanography Centre, Southampton, United Kingdom;Carl Sagan Center, SETI Institute, Mountain View, CA, United States;Centre for Marine Biodiversity and Biotechnology, Heriot-Watt University, Edinburgh, United Kingdom;Centro de Astrobiología (CSIC-INTA), Madrid, Spain;Department of Astronomy, Cornell University, Ithaca, NY, United States;Faculty of Marine Sciences, King Abdulaziz University, Jeddah, Saudi Arabia;Instituto Español de Oceanografía (IEO), Málaga, Spain;Marine Conservation International, Edinburgh, United Kingdom;Museum National d'Histoire Naturelle, PATRINAT, Paris, France;NASA Ames Research Center, Moffett Field, CA, United States;

关键词: planetary exploration;    rapid environmental assessment;    life detection;    macrophytes;    diatoms;    high altitude lakes;   

DOI  :  10.3389/fenvs.2019.00070

来源: DOAJ

【 摘 要 】

On our planet, aqueous environments such as deep sea or high-altitude aphotic lakes, subject to present or past volcanic activity and active deglaciation, may provide analogs to the aqueous environments found on such planetary bodies as Europa, Titan or Enceladus. We report here on the methodologies and technologies tested in Laguna Negra, a high altitude lake in the Central Andes, Chile, for exploring and assessing the presence of life within planetary lakes or interior oceans. We adopted a multi-parametric Rapid Ecological Assessment (REA) approach centered around collecting video imagery (by an Underwater Imaging System) and sampling benthic sediments (for sedimentological, biological and geochemical analysis) to depths of 272 m, to complement physico-chemical sampling of the water column and collection of shallow sediments for microbiological analysis (reported in separate publications). This enabled us to classify and assess the apparent status of benthic habitats, based on substrata and environmental characteristics, together with floral and faunal community characteristics and bioturbation artifacts. Video imagery showed that the lower water column was characterized by a variably intense sestonic flux of particles and debris, among which were planktonic organisms such as ostracods, copepods, and possibly cladocerans. Sediment analysis revealed at all depths abundant diatom frustules, mainly of an acidophile pennade diatom Pinnularia acidicola, amid vegetal debris likely originating from littoral macrophytes. Video imagery showed that the lakebed was partly covered by microbial mats and depositional matter and harbored an unexpectedly rich assortment of macrofauna, including sponges, tubificid worms, flatworms, bivalves and crustaceans. Various forms of bioturbation were also encountered, some with the animals in the tracks. Most notably, at the deepest site, a previously undescribed faunal feature was evident, apparently formed by a mat-like community of several layers of what appeared to be polychaete tubeworms, possibly of the family Siboglinidae. It is hypothesized that the hydrothermal activity observed in the region may supply the compounds able to support the deep-water microrganisms from which such tubeworms typically gain sustenance. Such processes could be present on other deep and aphotic liquid-water-bearing planetary bodies.

【 授权许可】

Unknown