Abstract EANA2025-112

Most hypotheses place the origin of life in an aquatic environment, making the subglacial oceans of Enceladus, Europa, or oceanic exoplanets privileged scenarios for assessing habitability beyond Earth. While awaiting data from upcoming missions such as JUICE (JUpiter ICy moons Explorer) by the European Space Agency (ESA), the study of extremotolerant terrestrial organisms is a key tool for extrapolating possible survival strategies in such environments.

Among these organisms, intertidal tardigrades stand out due to their remarkable ability to withstand multiple extreme conditions, including desiccation, overheating, and ionizing radiation. However, despite their relevance, the diversity and biology of marine tardigrades remain poorly explored, with fewer than 300 described species and limited molecular characterization. Our research aims to improve the current level of knowledge about these animals, using them as astrobiological models for studying habitability in exoplanets and ocean-bearing bodies within the Solar System.

After isolating live individuals from six genera collected from Caloplaca and Lichina pygmaea samples at Portiño Beach (Galicia, northwestern Spain), we established laboratory cultures of different marine tardigrade species at CIM-UVigo. The goal is to maintain specimens under controlled conditions, thereby reducing variability that could affect astrobiological experiments. Moreover, these cultures allow for deeper insights into their biology, including life cycles and resistance mechanisms.

A key part of our work focuses on evaluating their response to alterations in the magnetic field—a factor rarely studied but potentially relevant for life on planets or moons with weak or, conversely, stronger magnetospheres than Earth’s. To this end, we are conducting experiments involving both shielding from the terrestrial geomagnetic field and exposure to hypermagnetic fields, recording differences in survival and reproductive capacity in active individuals of the genera Ramazzottius and Echiniscoides. These experiments complement previous studies [1],[2] that focused exclusively on limno-terrestrial tardigrades under geomagnetic shielding conditions and broaden our understanding of the habitability limits of these organisms.

Special acknowledgments to: Inés Pazos (CACTI - UVIGO), Arantxa Martínez (CIM-ECIMAT), Carmen Sieiro (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.