Habitable Conditions Research Articles

Does the karst spring improve fish abiotic habitat in mountain streams?

Mountain streams constitute challenging habitat for many fish species due to rapid and variable flow, cool temperature, and limited food resources. Groundwaters recharge by karst spring may however mitigate harsh habit conditions of mountain streams providing niches for different fish species. This study aims to assess the suitability of mountain streams, replenished by karst springs, for various fish species like alpine bullhead, European grayling, brown and brook trout. The study was conducted in the Chochołowski Stream in the Western Tatra Mountains, Poland. The assessment of abiotic habitat is based on different characteristics of hydrological and thermal regimes as well as water chemical composition investigated between 01.09.2012 and 31.09.2014. The findings reveal that: 1) downstream variability of habitat abiotic conditions (such as water temperature, flow, water chemical composition) may affect the distribution of fish species, 2) karst springs contribute up to 100% of the stream’s recharge during periods of winter low flow, 3) karstic groundwater reduces the variability and amplitudes of stream water temperature and weaken the periodicity in water temperature associated with daily course of air temperature and solar radiation, 4) groundwaters prevent stream freezing in winter and moderate summer temperatures, 5) increasing mineralisation of water below the spring recharge may positively affect fish distribution. The findings underscore the importance of karst springs in modifying the abiotic conditions of fish habitat in mountain streams.

X-Ray Emission of Nearby Low-mass and Sunlike Stars with Directly Imageable Habitable Zones

Stellar X-ray and UV radiation can significantly affect the survival, composition, and long-term evolution of the atmospheres of planets in or near their host star’s habitable zone (HZ). Especially interesting are planetary systems in the solar neighborhood that may host temperate and potentially habitable surface conditions, which may be analyzed by future ground- and space-based direct-imaging surveys for signatures of habitability and life. To advance our understanding of the radiation environment in these systems, we leverage ∼3 Ms of XMM-Newton and Chandra observations in order to measure three fundamental stellar properties at X-ray energies for 57 nearby FGKM stellar systems: the shape of the stellar X-ray spectrum, the luminosity, and the timescales over which the stars vary (e.g., due to flares). These systems possess HZs that will be directly imageable to next-generation telescopes such as the Habitable Worlds Observatory and ground-based Extremely Large Telescopes. We identify 29 stellar systems with L X/L bol ratios similar to (or less than) that of the Sun; any potential planets in the HZs of these stars therefore reside in present-day X-ray radiation environments similar to (or less hostile than) modern Earth, though a broader set of these targets could host habitable planets. An additional 19 stellar systems have been observed with the Swift X-ray Telescope; in total, only ∼30% of potential direct imaging target stars has been observed with XMM-Newton, Chandra, or Swift. The data products from this work (X-ray light curves and spectra) are available via a public Zenodo repository (doi:10.5281/zenodo.11490574).

Social and environmental dimensions of public spaces of the indigenous territory of the Sierra de Manantlan mountain range, Jalisco state, western Mexico

The social and environmental dimension of the public space occupants of the indigenous territory of the Sierra de Manantlan, Jalisco, has a crucial place in the heritage of Mexico, such is the case of its form of idiosyncrasy, mutual interaction, and coexistence. The cultural, political, and economic organizations the Sierra de Manantlan mark an identity of the native peoples, where their customs, communal life, and solidarity work are preserved. The research objective was to evaluate the social perception and environmental habitability conditions of public space occupants in the towns of Chacala and Telcruz. Therefore, semi-structured interviews were conducted for the primary actors in both study areas and 259 information cards were applied to the inhabitants with data regarding social interaction variables and meteorological conditions in two seasons (summer and winter of a calendar year). Regarding data analysis and statistical purposes, the Pearson and Spearman correlations was used according to the needs of the study. The results revealed that the occupants of public spaces mostly report the pleasure of interacting in said spaces; however, they indicate that they would like an intervention or remodeling in the place that would encourage greater interaction with their neighbors, family, and friends. Another additional fact is that climatic variables, especially in summer, harm the desire to attend or stay in said spaces because of the lack of natural elements or bioclimatic devices that mitigate the environmental impact.

Building and system design's impact on thermal resilience to overheating during heatwaves: An uncertainty and sensitivity analysis

Rising heatwaves necessitate thermally resilient buildings to mitigate occupant heat-stress and mortality, ensuring habitable conditions during thermal shocks. This study's aim and novelty is to identify key design parameters affecting three thermal resilience aspects -(i) shock impact or SET-Dh i.e., degree hours above standard effective temperature threshold of 28 °C (ii) absorptivity time (tabs) and (iii) recovery time (trec) across varying degrees of shock intensities (doS-low, medium and high). A reference Belgian apartment is simulated with varying design parameters (building orientation, envelope and glazing properties, glazing percentage, airtightness, operation and control of passive strategies, cooling systems) during three types of heatwaves. Uncertainty analysis quantified the impact of design variations on thermal resilience, while global sensitivity analysis pinpointed key parameters affecting resilience during different shocks. The study shows that while 87 % of design variations remain thermally resilient during shorter shocks, only 21 % do so during longer shocks and that WWR, cooling capacity, and passive strategies (operation of natural night ventilation and solar shading) have twice the impact on thermal resilience compared to building orientation and glazing properties. While tabs is affected by heat build-up factors (e.g., WWR, solar shading), trec is influenced by heat removal factors (e.g., cooling capacity, NNV). Parameters such as heavy thermal mass extend heat absorption but also delays heat dissipation during prolonged heatwaves. This study guides designers and architects to focus on interventions that enhance buildings' thermal resilience during both short and long heatwaves, aiding in climate adaptation and the ability to withstand future extreme heat periods.

Eccentric orbits may enhance the habitability of Earth-like exoplanets

ABSTRACT The detection and characterization of Earth-like planets around Sun-like stars is an important goal of exoplanetary research, given their promise for hosting potentially habitable conditions. Key orbital parameters, such as eccentricity, can influence a planet’s climate response and, as a consequence, affect its potential habitability. Utilizing the Earth System Model – the Whole Atmosphere Community Climate Model (WACCM6), we simulated Earth-like exoplanets with two different orbital parameters: one circular ($e = 0$) and another highly eccentric ($e = 0.4$), both with zero obliquity but fixing the annual mean insolation. The highly eccentric case exhibits a 1.9 K warmer surface temperature due to lower surface and cloud albedo and a weaker longwave cloud forcing. Exploring the annual global mean climate difference, we analysed latitudinal and seasonal variations in hydrological cycle variables, such as sea ice, land snow, and clouds. Land habitability metrics based on temperature and precipitation reveal that the $e=0.4$ case has over 25 per cent more habitable land area for more than 80 per cent of its orbit, compared with the $e=0$ case. Additionally, the global circulation pattern shifts from a three-cell to a two-cell system in the $e=0.4$ case, expanding the Hadley cell to higher latitudes, enhancing meridional latent heat transport, and improving land habitability at higher latitudes. Our study suggests that Earth-like exoplanets with high eccentricity orbiting Sun-like stars may have greater land habitability than their circular counterparts, due to seasonally warmer surface temperatures and more evenly distributed precipitation over land.

Sediment subduction in Hadean revealed by machine learning

Due to the scarcity of rock samples, the Hadean Era predating 4 billion years ago (Ga) poses challenges in understanding geological processes like subaerial weathering and plate tectonics that are critical for the evolution of life. The Jack Hills zircon from Western Australia, the primary Hadean samples available, offer valuable insights into magma sources and tectonic genesis through trace element signatures. However, a consensus on these signatures has not been reached. To address this, we developed a machine learning classifier capable of deciphering the geochemical fingerprints of zircon. This allowed us to identify the oldest detrital zircon originating from sedimentary-derived "S-type" granites. Our results indicate the presence of S-type granites as early as 4.24 Ga, persisting throughout the Hadean into the Archean. Examining global detrital zircon across Earth's history reveals consistent supercontinent-like cycles from the present back to the Hadean. These findings suggest that a significant amount of Hadean continental crust was exposed, weathered into sediments, and incorporated into the magma sources of Jack Hills zircon. Only the early operation of both subaerial weathering and plate subduction can account for the prevalence of S-type granites we observe. Additionally, the periodic evolution of S-type granite proportions implies that subduction-driven tectonic cycles were active during the Hadean, at least around 4.2 Ga. The evidence thus points toward an early Earth resembling the modern Earth in terms of active tectonics and habitable surface conditions. This suggests the potential for life to originate in environments like warm ponds rather than extreme hydrothermal settings.

Carbon Cycle Instability for High-CO2 Exoplanets: Implications for Habitability

Implicit in the definition of the classical circumstellar habitable zone (HZ) is the hypothesis that the carbonate-silicate cycle can maintain clement climates on exoplanets with land and surface water across a range of instellations by adjusting atmospheric CO2 partial pressure (pCO2). This hypothesis is made by analogy to the Earth system, but it is an open question whether silicate weathering can stabilize climate on planets in the outer reaches of the HZ, where instellations are lower than those received by even the Archean Earth and CO2 is thought likely to dominate atmospheres. Since weathering products are carried from land to ocean by the action of water, silicate weathering is intimately coupled to the hydrologic cycle, which intensifies with hotter temperatures under Earth-like conditions. Here, we use global climate model simulations to demonstrate that the hydrologic cycle responds counterintuitively to changes in climate on planets with CO2-H2O atmospheres at low instellations and high pCO2, with global evaporation and precipitation decreasing as pCO2 and temperatures increase at a given instellation. Within the Maher & Chamberlain (or MAC) weathering formulation, weathering then decreases with increasing pCO2 for a range of instellations and pCO2 typical of the outer reaches of the HZ, resulting in an unstable carbon cycle that may lead to either runaway CO2 accumulation or depletion of CO2 to colder (possibly snowball) conditions. While the behavior of the system has not been completely mapped out, the results suggest that silicate weathering could fail to maintain habitable conditions in the outer reaches of the nominal HZ.

RECONSTRUCTION OF THE PALEOCLIMATE WITHIN THE BOUNDARIES OF AN ANCIENT SETTLEMENT NEAR THE KOROBCHYNE VILLAGE IN THE KIROVOHRAD REGION (PALEOPEDOLOGICAL ASPECT)

Climate is the main factor determining the change of paleolandscapes and their components. When studying the climates of the historical past beyond the period of instrumental observations, secondary climate indicators, chronicles, other literary sources and testimonies, monuments of material culture, etc. can be used. The methodological techniques of paleogeography are based on the studied monuments of ancient nature, which can be indicators of the paleoclimate and give certain indicators of it. Geomorphological, lithological, paleopedological, archaeological and other data are important for climate analysis. An important and fundamental problem in paleogeography today is the study of modern and ancient soils with the help of soil-archaeological approaches (macro- and micromorphological, geoarchaeological or chrono-series methods), which are now increasingly used to reconstruct the natural conditions of ancient human habitation in key areas within geological or archaeological objects. Research of ancient and modern soils within the ancient settlement near the village Korobchyne in Kirovohrad Region using paleopedological and micromorphological methods combined with a geoarchaeological approach to establish trends in soil development and climatic changes over time is extremely relevant for the evolution of soils in their relationship with the geographic environment. In the process of researching an ancient settlement near the Korobchynе village, we found out that the conditions of human existence in Vytachev's time were more acceptable, which is evident from the nature of the sediments and soils. This section corresponds to the situation when man developed watersheds and high terraces under warmer climatic conditions. In conditions of cooling of the climate (we studied earlier in this area the sections and layers of flints within the settlements near the villages of Troyanovе and Shmidovе), people settled in depressions, closer to water bodies, where vegetation was richer than on watersheds. So, the change in climatic conditions affected the change in the niches occupied by ancient man. Key words: paleoclimate; soil; paleopedological method; geoarchaeological approach.

Magnetohydrodynamic simulations of the space weather in Proxima b: Habitability conditions and radio emission

Magnetohydrodynamic simulations of the space weather in Proxima b: Habitability conditions and radio emission

Quantifying the Potential for Nitrate-Dependent Iron Oxidation on Early Mars: Implications for the Interpretation of Gale Crater Organics.

Geological evidence and atmospheric and climate models suggest habitable conditions occurred on early Mars, including in a lake in Gale crater. Instruments aboard the Curiosity rover measured organic compounds of unknown provenance in sedimentary mudstones at Gale crater. Additionally, Curiosity measured nitrates in Gale crater sediments, which suggests that nitrate-dependent Fe2+ oxidation (NDFO) may have been a viable metabolism for putative martian life. Here, we perform the first quantitative assessment of an NDFO community that could have existed in an ancient Gale crater lake and quantify the long-term preservation of biological necromass in lakebed mudstones. We find that an NDFO community would have the capacity to produce cell concentrations of up to 106 cells mL-1, which is comparable to microbes in Earth's oceans. However, only a concentration of <104 cells mL-1, due to organisms that inefficiently consume less than 10% of precipitating nitrate, would be consistent with the abundance of organics found at Gale. We also find that meteoritic sources of organics would likely be insufficient as a sole source for the Gale crater organics, which would require a separate source, such as abiotic hydrothermal or atmospheric production or possibly biological production from a slowly turning over chemotrophic community.

Marine Science Can Contribute to the Search for Extra-Terrestrial Life.

Life on our planet likely evolved in the ocean, and thus exo-oceans are key habitats to search for extraterrestrial life. We conducted a data-driven bibliographic survey on the astrobiology literature to identify emerging research trends with marine science for future synergies in the exploration for extraterrestrial life in exo-oceans. Based on search queries, we identified 2592 published items since 1963. The current literature falls into three major groups of terms focusing on (1) the search for life on Mars, (2) astrobiology within our Solar System with reference to icy moons and their exo-oceans, and (3) astronomical and biological parameters for planetary habitability. We also identified that the most prominent research keywords form three key-groups focusing on (1) using terrestrial environments as proxies for Martian environments, centred on extremophiles and biosignatures, (2) habitable zones outside of "Goldilocks" orbital ranges, centred on ice planets, and (3) the atmosphere, magnetic field, and geology in relation to planets' habitable conditions, centred on water-based oceans.

Hydrochemical and isotopic characteristics of water sources for biological activity across a massive evaporite basin on the Tibetan Plateau: Implications for aquatic environments on early Mars

Covered by vast eolian landforms, gravel deposits, and playas, the worldwide typical evaporite deposit land, Qaidam Basin, in northwestern China is analogous to early Mars when the aridification process had lasted for millions of years since the end of a wetter climate. This study aims to investigate the chemical and isotopic characteristics of waters in an evaporite-rich environment, as well as the habitable conditions therein, that have undergone a transformation similar to early Mars. In May 2023, a total of 26 water samples were collected across the representative central axis of a longitudinal aridity gradient in the Qaidam Basin, including categories of meteoric water, freshwater, standing water accumulated after precipitation, salty lacustrine water, and hypersaline brines to inspect compounds made up of carbon, nitrogen, phosphorus, sulfur, halogen, and metallic elements. As evaporation intensified, the salt types transformed from HCO3-Ca·Na to Cl·SO4-Na or ClMg. The dominance of carbonate will gradually be replaced by sulfate and chloride, leaving much more dilute and less detectable contents. The presence of trace ClO4−, ClO3−, ClO2−, and BrO3− was confirmed in a few of the sampled Qaidam waters, indicating the preservation of oxyhalides in waters within an arid region and possibly the presence of relevant microbial enzymes. The isotopes of water, carbonaceous, and nitrogenous compounds provide valuable references for either abiogenic or biogenic signatures. With undetectable amount, phosphorus was found to be the limiting nutrient in evaporative aquatic environments but not necessarily antibiosignatures. Overall, these results suggest that the paleo-lacustrine environments on Mars are more likely to preserve biosignatures if they feature the dominance of carbonate minerals, bioavailable nitrate, phosphorus, and organic carbon, the presence of thermodynamically unstable oxyhalides, and isotope ratios that point to the involvement of biological activity.

Towards Extensive Definition and Planning of Energy Resilience in Buildings in Cold Climate

The transition towards a sustainable future requires the reliable performance of the building’s energy system in order for the building to be energy-resilient. “Energy resilient building in cold climates” is an emerging concept that defines the ability to maintain a minimum level of indoor air temperature and energy performance of the building and minimize the occupant’s health risk during a disruptive event of the grid’s power supply loss in a cold climate. The aim is to introduce an extensive definition of the energy resilience of buildings and apply it in case studies. This article first reviews the progress and provides an overview of the energy-resilient building concept. The review shows that most of the relevant focus is on short-term energy resilience, and the serious gap is related to long-term resilience in the context of cold regions. The article presents a basic definition of energy resilience of buildings, a systematic framework, and indicators for analyzing the energy resilience of buildings. Terms such as active and passive habitability, survivability, and adaptive habitable conditions are defined. The energy resilience indicators are applied on two simulated Finnish case studies, an old building and a new building. By systematic analysis, using the defined indicators and thresholds, the energy resilience performance of the buildings is calculated and compared. Depending on the type of the building, the results show that the robustness period is 11 h and 26 h for the old building and the new building, respectively. The old building failed to provide the habitability conditions. The impact of the event is 8.9 °C, minimum performance (Pmin) is 12.54 °C, and degree of disruption (DoD) is 0.300 for the old building. The speed of collapse (SoC) is 3.75 °C/h, and the speed of recovery (SoR) is 0.64 °C/h. On the other hand, the new building performed better such that the impact of the event is 4 °C, Pmin is 17.5 °C, and DoD is 0.138. The SoC is slow 3.2 °C/h and SoR is fast 0.80 °C/h for the new building. The results provide a pathway for improvements for long-term energy resilience. In conclusion, this work supports society and policy-makers to build a sustainable and resilient society.

Potential climates and habitability on Gl 514 b: a super-Earth exoplanet with high eccentricity

ABSTRACT The recently discovered super-Earth Gl 514 b, orbiting a nearby M0.5-1.0 star at 7.6 pc, is one of the best benchmark exoplanets for understanding the potential climate states of eccentric planets. The elongated (e = 0.45$^{+0.15}_{-0.14}$) orbit of Gl 514 b, which only partially lies in the Conservative Habitable Zone, suggests a dynamically young system, where the spin-orbit tidal synchronization may not have yet occurred up to the present time. In the present work, we use a seasonal-latitudinal energy balance model, EOS-ESTM, to explore the potential impact of both constrained and unconstrained planetary, orbital, and atmospheric parameters on the Gl 514 b habitability, mapped in terms of surface temperature. We test three distinct CO2-dominated atmospheres by varying the CH4 concentration values (0 per cent, 0.1 per cent, and 1 per cent) and the total surface pressure. As a general trend, we find that habitable conditions are favoured by high-CH4 and high-pressure regimes. Habitability also increases for high-axis obliquities (at least until the appearance of an icebelt), long-rotation periods, and high-ocean fractional coverage. If the ocean fraction is low, then also the argument of periastron becomes relevant. Our results are robust against changes of the continental distribution. Thus, we conclude that Gl 514 b can potentially maintain temperate surface conditions with modest seasonal temperature variations under a wide variety of planetary, orbital, and atmospheric conditions. Despite no transit have been detected yet, the results found in this work should motivate the community to invest time in future observations.

Вплив «сільських» поведінкових стратегій населення України на якість життя в умовах війни

The purpose of the article is to analyse and understand how «rural» behavioural aspects of the Ukrainian population influence the perception and adaptation to the conditions of armed conflict. The novelty of the study lies in the analysis of those rural behavioural aspects that are common to the entire population and may impact adaptation strategies and the improvement of quality of life during military events. In the context of modern conflicts and war scenarios, the study of population behaviour and its impact on the resilience of quality of life becomes particularly significant. Military conflicts not only threaten the safety and stability of society but also sharply increase the importance of understanding population behavioural aspects in the conditions of armed conflict and their impact on the quality of life. The examination of population behaviour during an extreme period of armed conflict potentially provides answers to how effectively the Ukrainian population can adapt to economic difficulties and overcome them. For the investigation of the impact of «rural» behavioural aspects on the quality of life of the population in Ukraine, a combination of specialized and general scientific methods was employed. These include the monographic method, bibliometrics, and content analysis. Additionally, forecasting and modelling methods were utilized to predict the impact of fullscale military actions on poverty, a key indicator of quality of life. After the conducted research, it can be noted that in the conditions of a full-scale invasion by Russian forces, the «rural» behavioural characteristics of Ukrainians exhibit numerous advantages, arising from the close interaction between rural and urban existence. It is demonstrated that a potentially significant portion of the country’s population, particularly those of rural origin, possesses skills in land management. The presence of relatives in villages and small towns, who have large living spaces and substantial land plots, enabled the acceptance of many forcibly displaced individuals during the war. The study confirms that behavioural traits such as the tradition of stockpiling food supplies, maintaining habitable housing conditions in rural areas, and the existence of close familial and social ties have significantly mitigated the impact of the war on the population.

Store and cost of medicine in Libya house.

Background: The way we store our medications affects their effectiveness. When patients need to take their prescriptions outside the home, the health care provider should advise them on how to transport and store them safely. Objective: This study aimed to investigate or determine the storage conditions of medicines, usage habits, and cost of medications in households in Libya. Methods: This cross-sectional study included questionnaires conducted randomly in 100 Libyan homes. Householders were informed in advance of the survey, which took place from September to November 2023. Results: the final questionnaire included the following sections: there was demographic data on household storage of medicines in Libya, types of medications found in Libyan households, places for drugs were stored in Libyan households, factors related to medications in Libyan households, and cost of drugs found in Libyan households. Conclusion: the prevalence of household drug storage in 100-libya households was analgesics, antihypertension, and antiasthmatic. Most drugs kept at home were not appropriately labeled or stored in a safe place. This study highlights the urgent need for improved awareness and education regarding proper medication storage and labeling in Libyan households.

The hydrology of the Jezero crater paleolake: Implications for the climate and limnology of the lake system from hydrological modeling

Jezero crater, the landing site of the Perseverance rover, hosts sedimentary fan deposits, aqueously altered sedimentary rock, and an outlet breach of the crater rim, all of which indicates that a long-lived lake (or lakes) once existed within the crater. The deltaic deposits in the crater may preserve evidence of habitable conditions within the past lake system, which would have been influenced by the climate and conditions of the past hydrological system within the watersheds and basin. However, the aqueously altered sedimentary deposits within Jezero are less extensive than those found in other crater lakes on Mars, like Gale with a crater filling mound of cemented sediment. In this work we use hydrological models of the past Jezero lake system to constrain the climatic and hydrological conditions by comparing model predictions to the proposed lake stands and mineralogy in the crater observed from orbit and by the Perseverance rover thus far. We then compare these results to Gale crater to understand the influence of basin hydrology on the depositional setting found within past crater lakes. We show that a lake forming at the outlet breach elevation or higher in Jezero requires a semiarid or wetter-arid climate, consistent with previous estimates. An integrated hydrologic system with seasonal variations similar to arid and semiarid climates on Earth results in a lake system at Jezero characterized by both surface and subsurface outflow from the lake. Outflow to the subsurface and through the outlet breach will remove dissolved solids from the lake system, mitigating large-scale evaporite cementation within the Jezero basin, which is in contrast to Gale crater, where subsurface inflow constituted a larger percentage of the total inflow to the lake and all loss was through evaporation due to the setting in a deeper impact crater. Furthermore, at hyperarid climatic and/or groundwater-driven hydrological conditions, lake formation within Jezero would have ceased while a lacustrine depositional environment would have continued at Gale. This highlights the importance of considering basin hydrology, in addition to climate, when interpreting lacustrine sedimentary deposits in craters on Mars.

Chapter 7: Assessing Habitability Beyond Earth.

All known life on Earth inhabits environments that maintain conditions between certain extremes of temperature, chemical composition, energy availability, and so on (Chapter 6). Life may have emerged in similar environments elsewhere in the Solar System and beyond. The ongoing search for life elsewhere mainly focuses on those environments most likely to support life, now or in the past-that is, potentially habitable environments. Discussion of habitability is necessarily based on what we know about life on Earth, as it is our only example. This chapter gives an overview of the known and presumed requirements for life on Earth and discusses how these requirements can be used to assess the potential habitability of planetary bodies across the Solar System and beyond. We first consider the chemical requirements of life and potential feedback effects that the presence of life can have on habitable conditions, and then the planetary, stellar, and temporal requirements for habitability. We then review the state of knowledge on the potential habitability of bodies across the Solar System and exoplanets, with a particular focus on Mars, Venus, Europa, and Enceladus. While reviewing the case for the potential habitability of each body, we summarize the most prominent and impactful studies that have informed the perspective on where habitable environments are likely to be found.

Considerations for Detecting Organic Indicators of Metabolism on Enceladus.

Enceladus is of interest to astrobiology and the search for life since it is thought to host active hydrothermal activity and habitable conditions. It is also possible that the organics detected on Enceladus may indicate an active prebiotic or biotic system; in particular, the conditions on Enceladus may favor mineral-driven protometabolic reactions. When including metabolism-related biosignatures in Enceladus mission concepts, it is necessary to base these in a clearer understanding of how these signatures could also be produced prebiotically. In addition, postulating which biological metabolisms to look for on Enceladus requires a non-Earth-centric approach since the details of biological metabolic pathways are heavily shaped by adaptation to geochemical conditions over the planet's history. Creating metabolism-related organic detection objectives for Enceladus missions, therefore, requires consideration of how metabolic systems may operate differently on another world, while basing these speculations on observed Earth-specific microbial processes. In addition, advances in origin-of-life research can play a critical role in distinguishing between interpretations of any future organic detections on Enceladus, and the discovery of an extant prebiotic system would be a transformative astrobiological event in its own right.

Speed of thermal adaptation of terrestrial vegetation alters Earth's long-term climate.

Earth's long-term climate is driven by the cycling of carbon between geologic reservoirs and the atmosphere-ocean system. Our understanding of carbon-climate regulation remains incomplete, with large discrepancies remaining between biogeochemical model predictions and the geologic record. Here, we evaluate the importance of the continuous biological climate adaptation of vegetation as a regulation mechanism in the geologic carbon cycle since the establishment of forest ecosystems. Using a model, we show that the vegetation's speed of adaptation to temperature changes through eco-evolutionary processes can strongly influence global rates of organic carbon burial and silicate weathering. Considering a limited thermal adaptation capacity of the vegetation results in a closer balance of reconstructed carbon fluxes into and out of the atmosphere-ocean system, which is a prerequisite to maintain habitable conditions on Earth's surface on a multimillion-year timescale. We conclude that the long-term carbon-climate system is more sensitive to biological dynamics than previously expected, which may help to explain large shifts in Phanerozoic climate.