Abstract_EANA2024-55

Abstract EANA2024-55

Progress in the Culture of Marine Tardigrades: Astrobiological Model for Studying Life in Extraterrestrial Oceanic Environments

Cintia Cabada (1,2), Ulla-Miguel, Ana (1,3,4), Marcos Rubal (5), Daniel Rey (2), Yara Meleán (2), Milagrosa Aldana (6)

1: Astronomy, Astrophysics, Cultural Anthropology, and Education Group (AS1-A3CE), University of Vigo (Spain), 2: Marine Research Centre (CIM-UVIGO, Spain), 3: Applied Physics Department, University of Vigo (Spain), 4: Institute of Physics and Aerospace Sciences (IFCAE-UVIGO, Spain), 5: Centre of Molecular and Environmental Biology (CBMA-UMinho, Portugal), 6: Simón Bolívar University (Venezuela)

Most hypotheses place the origin of life in an aquatic environment, making oceanic celestial bodies such as Enceladus, Europa, and certain exoplanets excellent candidates in the search for extraterrestrial life. While we await data from the European Space Agency's JUICE (JUpiter ICy moons Explorer) mission, which may help us evaluate the habitability conditions of these places, investigating terrestrial habitats as extraterrestrial analogues is essential for obtaining extrapolatable data.

One such habitat is the intertidal zones, extreme environments where desiccation, overheating, and exposure to ultraviolet radiation are common. These areas harbour marine tardigrades, bilateral invertebrate animals known for their excellent polyextremophilic behaviour and stress resistance. Despite studies across a wide range of habitats, marine tardigrades remain relatively unexplored, with fewer than 300 species described. Our research aims to improve the current level of knowledge of these animals through the study of marine tardigrades as models of extraterrestrial habitability, particularly concerning bodies within the Solar System and oceanic exoplanets.

In this study, we collected several samples of Caloplaca, Lichina pygmaea and macroalgae of the genus Ulva at Portiño Beach (Galicia, northwest Spain). After isolating live individuals using different treatments, six genera were identified: Ramazzottius, Macrobiotus, Milnesium, Echiniscoides, Styraconyx, and Batillipes. Individuals of different ages, as well as eggs, were isolated. Morphological differences were also observed between taxa and between females and males in some genera. Individuals of Echiniscoides and Ramazzottius were selected to establish long-term cultures under laboratory conditions, testing different substrates, food sources, and desiccation-hydration cycles. We will present the results obtained, including observations on life cycles and resistance mechanisms.

Our study also aims to gather information on the response of marine tardigrades in active or resistant states to different stress conditions. To induce cryptobiosis in tardigrades, desiccation is one of the most commonly used methods in laboratories. However, the desiccation rate significantly affects the survival rate of individuals undergoing this process. Therefore, we conducted desiccation tests on tardigrades of the genera Ramazzottius using substrates with different water retention capacities. Additionally, we are evaluating the influence of hypomagnetic conditions on this taxon, for which there are very few studies [1], [2]. To do this, we will compare the results obtained in the genera Echiniscoides and Ramazzottius.

Acknowledgments:

Special acknowledgments to: Inés Pazos (CACTI - UVIGO), Arantxa Martínez (CIM-ECIMAT), Carmen Sieiro and Lara Areal (Functional Biology and Health Sciences - UVIGO) and Miguel Otero (CIM-GEOMA).

REFERENCES:

[1] W. Erdmann, B. Idzikowski, W. Kowalski, B. Szymański, J. Z. Kosicki, y Ł. Kaczmarek, «Can the tardigrade Hypsibius dujardini survive in the absence of the geomagnetic field?», PLoS ONE, vol. 12, n.o 9, p. e0183380, sep. 2017, doi: 10.1371/journal.pone.0183380.

[2] A. K. Nagwani, A. Budka, A. Łacka, Ł. Kaczmarek, y H. Kmita, «The effect of hypomagnetic field on survival and mitochondrial functionality of active Paramacrobiotus experimentalis females and males of different age», Front. Physiol., vol. 14, p. 1253483, sep. 2023, doi: 10.3389/fphys.2023.1253483.