How long can tardigrades survive in the anhydrobiotic state? A search for tardigrade anhydrobiosis patterns

Abstract

Anhydrobiosis is a desiccation tolerance that denotes the ability to survive almost complete dehydration without sustaining damage. The knowledge on the survival capacity of various tardigrade species in anhydrobiosis is still very limited. Our research compares anhydrobiotic capacities of four tardigrade species from different genera, i.e. Echiniscus testudo, Paramacrobiotus experimentalis, Pseudohexapodibius degenerans and Macrobiotus pseudohufelandi, whose feeding behavior and occupied habitats are different. Additionally, in the case of Ech. testudo, we analyzed two populations: one urban and one from a natural habitat. The observed tardigrade species displayed clear differences in their anhydrobiotic capacity, which appear to be determined by the habitat rather than nutritional behavior of species sharing the same habitat type. The results also indicate that the longer the state of anhydrobiosis lasts, the more time the animals need to return to activity.

Long-Term Survivability of Tardigrade Paramacrobiotus experimentalis (Eutardigrada) at Increased Magnesium Perchlorate Levels: Implications for Astrobiological Research

“…Anhydrobiosis in tardigrades is a complex phenomenon. It includes entering, permanent, and leaving steps, which correspond to dehydration (tun formation), tun state (desiccated state), and rehydration, respectively [ 31 ]. These steps are well known at the level of the organism’s morphology [ 32 ], but a full understanding of their mechanisms requires the consideration of additional factors.…”

Ecology explains anhydrobiotic performance across tardigrades, but the shared evolutionary history matters more

“…(2009), who tested Δ recovery (difference between motility at 1 and 24 h after rehydration) in a population then identified as ‘ P. richtersi ’ (now known to represent as P. spatialis Guidetti et al., 2019) at different desiccation conditions. Two other studies (Roszkowska et al., 2023; Roszkowska, Gołdyn, et al., 2021) tested the recovery time (as time to movement after rehydration) against the anhydrobiosis duration. We found that the two components— p and Q —despite being generally correlated, can still show a non‐negligible independence (Figure 3) and should therefore be considered jointly when analysing anhydrobiotic performance.…”

“…Despite decades of research on anhydrobiosis, most of the research effort has been devoted to the understanding of the physiological and molecular mechanisms that allow animals to survive almost complete desiccation (see any of the many reviews published on the topic, for example: Arakawa, 2022; Hibshman et al., 2020; Rebecchi et al., 2020; Sogame & Kikawada, 2017). In contrast, the interplay between anhydrobiosis and evolutionary processes or how evolutionary and ecological pressures lead to this astonishing adaptation are still poorly studied (Kaczmarek et al., 2019; McGill et al., 2015; Ricci & Caprioli, 2005; Roszkowska et al., 2023).…”

“…Although some studies (e.g. Giovannini, Boothby, et al., 2022; Roszkowska et al., 2023) did record the proportion of motile animals at different time points, each time step was analysed separately (e.g. when comparing treatment groups), thus dismissing the temporal autocorrelation in this type of data.…”

Effects of synthetic acid rain and organic and inorganic acids on survival and CaCO3 piercing stylets in tardigrades

“…All terrestrial (i.e., living in moss, lichen, and soil) and aquatic (marine and freshwater) dwelling tardigrades, require a layer of liquid water to be active. Despite this, if in their substrate the water becomes unavailable, for example, by freezing or evaporation, many tardigrade species can enter a suspended cryptobiotic life state or form cysts (Bertolani et al, 2019; Guidetti et al, 2011; Janelt & Poprawa, 2020; Møbjerg et al, 2011; Rebecchi et al, 2007, 2020; Roszkowska et al, 2020, 2023; Møbjerg & Nives, 2021). Tardigrades can withstand many harsh environmental stressors (such as radiations, pollutants, and others), both in their hydrated state, as well as in their cryptobiotic state (e.g., Altiero et al, 2011; Giovannini et al, 2018; Horikawa et al, 2006; Hygum et al, 2017; for a review see Møbjerg & Neves, 2021).…”