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1.
J Vis Exp ; (168)2021 02 27.
Artigo em Inglês | MEDLINE | ID: mdl-33720128

RESUMO

Deep sea hydrothermal vents are self-organizing precipitates generated from geochemical disequilibria and have been proposed as a possible setting for the emergence of life. The growth of hydrothermal chimneys in a thermal gradient environment within an early Earth vent system was successfully simulated by using different hydrothermal simulants, such as sodium sulfide, which were injected into an early Earth ocean simulant containing dissolved ferrous iron. Moreover, an apparatus was developed to sufficiently cool the ocean simulant to near 0 °C in a condenser vessel immersed in a cold water bath while injecting a sulfide solution at hot to room temperatures, effectively creating an artificial chimney structure in a temperature gradient environment over a period of a few hours. Such experiments with different chemistries and variable temperature gradients resulted in a variety of morphologies in the chimney structure. The use of ocean and hydrothermal fluid simulants at room temperature resulted in vertical chimneys, whereas the combination of a hot hydrothermal fluid and cold ocean simulant inhibited the formation of robust chimney structures. The customizable 3D printed condenser created for this study acts as a jacketed reaction vessel that can be easily modified and used by different researchers. It will allow the careful control of injection rate and chemical composition of vent and ocean simulants, which should help accurately simulate prebiotic reactions in chimney systems with thermal gradients similar to those of natural systems.


Assuntos
Simulação por Computador , Planeta Terra , Fontes Hidrotermais , Temperatura , Oceanos e Mares , Impressão Tridimensional , Soluções
2.
Nat Commun ; 12(1): 1198, 2021 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-33608528

RESUMO

Understanding how species' thermal limits have evolved across the tree of life is central to predicting species' responses to climate change. Here, using experimentally-derived estimates of thermal tolerance limits for over 2000 terrestrial and aquatic species, we show that most of the variation in thermal tolerance can be attributed to a combination of adaptation to current climatic extremes, and the existence of evolutionary 'attractors' that reflect either boundaries or optima in thermal tolerance limits. Our results also reveal deep-time climate legacies in ectotherms, whereby orders that originated in cold paleoclimates have presently lower cold tolerance limits than those with warm thermal ancestry. Conversely, heat tolerance appears unrelated to climate ancestry. Cold tolerance has evolved more quickly than heat tolerance in endotherms and ectotherms. If the past tempo of evolution for upper thermal limits continues, adaptive responses in thermal limits will have limited potential to rescue the large majority of species given the unprecedented rate of contemporary climate change.


Assuntos
Evolução Biológica , Fenômenos Fisiológicos Vegetais , Termotolerância/fisiologia , Adaptação Fisiológica , Animais , Clima , Mudança Climática , Planeta Terra , Ecologia , Temperatura Alta , Temperatura
3.
Nat Commun ; 12(1): 1101, 2021 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-33597520

RESUMO

It is widely hypothesised that primeval life utilised small organic molecules as sources of carbon and energy. However, the presence of such primordial ingredients in early Earth habitats has not yet been demonstrated. Here we report the existence of indigenous organic molecules and gases in primary fluid inclusions in c. 3.5-billion-year-old barites (Dresser Formation, Pilbara Craton, Western Australia). The compounds identified (e.g., H2S, COS, CS2, CH4, acetic acid, organic (poly-)sulfanes, thiols) may have formed important substrates for purported ancestral sulfur and methanogenic metabolisms. They also include stable building blocks of methyl thioacetate (methanethiol, acetic acid) - a putative key agent in primordial energy metabolism and thus the emergence of life. Delivered by hydrothermal fluids, some of these compounds may have fuelled microbial communities associated with the barite deposits. Our findings demonstrate that early Archaean hydrothermal fluids contained essential primordial ingredients that provided fertile substrates for earliest life on our planet.


Assuntos
Archaea/química , Sulfeto de Hidrogênio/análise , Metano/análise , Compostos de Sulfidrila/análise , Sulfato de Bário/análise , Planeta Terra , Ecossistema , Microbiologia Ambiental , Evolução Química , Cromatografia Gasosa-Espectrometria de Massas , Geografia , Sedimentos Geológicos/química , Fatores de Tempo , Austrália Ocidental
4.
Nat Commun ; 12(1): 641, 2021 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-33510166

RESUMO

The colonization of land by fungi had a significant impact on the terrestrial ecosystem and biogeochemical cycles on Earth surface systems. Although fungi may have diverged ~1500-900 million years ago (Ma) or even as early as 2400 Ma, it is uncertain when fungi first colonized the land. Here we report pyritized fungus-like microfossils preserved in the basal Ediacaran Doushantuo Formation (~635 Ma) in South China. These micro-organisms colonized and were preserved in cryptic karstic cavities formed via meteoric water dissolution related to deglacial isostatic rebound after the terminal Cryogenian snowball Earth event. They are interpreted as eukaryotes and probable fungi, thus providing direct fossil evidence for the colonization of land by fungi and offering a key constraint on fungal terrestrialization.


Assuntos
Ecossistema , Eucariotos/crescimento & desenvolvimento , Fósseis , Fungos/crescimento & desenvolvimento , Animais , Evolução Biológica , China , Planeta Terra , Fatores de Tempo
5.
Nat Ecol Evol ; 5(3): 273-284, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33462488

RESUMO

As our planet emerges into a new epoch in which humans dominate the Earth system, it is imperative that societies initiate a new phase of responsible environmental stewardship. Here we argue that information from the past has a valuable role to play in enhancing the sustainability and resilience of our societies. We highlight the ways that past data can be mobilized for a variety of efforts, from supporting conservation to increasing agricultural sustainability and food security. At a practical level, solutions from the past often do not require fossil fuels, can be locally run and managed, and have been tested over the long term. Past failures reveal non-viable solutions and expose vulnerabilities. To more effectively leverage increasing knowledge about the past, we advocate greater cross-disciplinary collaboration, systematic engagement with stakeholders and policymakers, and approaches that bring together the best of the past with the cutting-edge technologies and solutions of tomorrow.


Assuntos
Conservação dos Recursos Naturais , Planeta Terra , Agricultura , Humanos
6.
Biochim Biophys Acta Bioenerg ; 1862(1): 148303, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-32926862

RESUMO

Photosynthesis converts sunlight into the chemical free energy that feeds the Earth's biosphere, yet at levels much lower than what thermodynamics would allow for. I propose here that photosynthesis is nevertheless thermodynamically limited, but this limit acts indirectly on the material exchange. I substantiate this proposition for the photosynthetic activity of terrestrial ecosystems, which are notably more productive than the marine biosphere. The material exchange for terrestrial photosynthesis involves water and carbon dioxide, which I evaluate using global observation-based datasets of radiation, photosynthesis, precipitation and evaporation. I first calculate the conversion efficiency of photosynthesis in terrestrial ecosystems and its climatological variation, with a median efficiency of 0.77% (n = 13,274). The rates tightly correlate with evaporation on land (r2 = 0.87), which demonstrates the importance of the coupling of photosynthesis to material exchange. I then infer evaporation from the maximum material exchange between the surface and the atmosphere that is thermodynamically possible using datasets of solar radiation and precipitation. This inferred rate closely correlates with the observation-based land evaporation dataset (r2 = 0.84). When this rate is converted back into photosynthetic activity, the resulting patterns correlate highly with the observation-based dataset (r2 = 0.66). This supports the interpretation that it is not energy directly that limits terrestrial photosynthesis, but rather the material exchange that is driven by sunlight. This interpretation can explain the very low, observed conversion efficiency of photosynthesis in terrestrial ecosystems as well as its spatial variations. More generally, this implies that one needs to take the necessary material flows and exchanges associated with life into account to understand the thermodynamics of life. This, ultimately, requires a perspective that links the activity of the biosphere to the thermodynamic constraints of transport processes in the Earth system.


Assuntos
Atmosfera , Ecossistema , Modelos Biológicos , Fotossíntese , Luz Solar , Planeta Terra , Termodinâmica
7.
Adv Genet ; 106: 119-122, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33081921

RESUMO

WHO's pronouncement of the 2019 novel coronavirus outbreak as a pandemic disease came months after we published a warning that the present deepest minimum of the sunspot cycle would be likely to facilitate the onset of a viral pandemic. During a deep sunspot minimum (deepest in 100 years) such as we are now witnessing, two space related phenomena could have an effect on the disposition of viral disease and potential pandemics. With the weakening of the magnetic field in the Earth's vicinity, there would be a high flux of mutagenic cosmic rays. These processes would be likely to herald the onset of new pandemics. Neutron counts from Moscow Neutron Monitor show that the flux of cosmic rays reaching Earth in 2019 was indeed at a maximum over a timespan of half a century since 1962. It is of interest to note that immediately prior to the first recorded cases of the novel Corona virus in China a peak of cosmic rays was measured as is indicated by the Huon neutron monitor data. Recent research revealed that estimates of the timing of the most recent common ancestor of COVID-19 made with current sequence data point to emergence of the virus in late November 2019 to early December 2019, compatible with the earliest retrospectively confirmed cases and the cosmic ray spike in late November 2019. In our view, this strong cosmic ray spike was in some way connected with the onset of the outbreak.


Assuntos
Evolução Biológica , Infecções por Coronavirus/etiologia , Radiação Cósmica , Pneumonia Viral/etiologia , Atividade Solar , Betacoronavirus/fisiologia , Betacoronavirus/efeitos da radiação , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/etiologia , Doenças Transmissíveis Emergentes/virologia , Infecções por Coronavirus/epidemiologia , Radiação Cósmica/efeitos adversos , Planeta Terra , História do Século XXI , Humanos , Nêutrons , Pandemias , Pneumonia Viral/epidemiologia
8.
Adv Genet ; 106: 75-100, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33081928

RESUMO

The origins and global spread of two recent, yet quite different, pandemic diseases is discussed and reviewed in depth: Candida auris, a eukaryotic fungal disease, and COVID-19 (SARS-CoV-2), a positive strand RNA viral respiratory disease. Both these diseases display highly distinctive patterns of sudden emergence and global spread, which are not easy to understand by conventional epidemiological analysis based on simple infection-driven human- to-human spread of an infectious disease (assumed to jump suddenly and thus genetically, from an animal reservoir). Both these enigmatic diseases make sense however under a Panspermia in-fall model and the evidence consistent with such a model is critically reviewed.


Assuntos
Evolução Biológica , Candidíase/etiologia , Doenças Transmissíveis Emergentes/etiologia , Infecções por Coronavirus/etiologia , Origem da Vida , Pneumonia Viral/etiologia , Animais , Betacoronavirus/isolamento & purificação , Betacoronavirus/fisiologia , Candida/isolamento & purificação , Candida/fisiologia , Candidíase/epidemiologia , Doenças Transmissíveis Emergentes/epidemiologia , Coronavirus/isolamento & purificação , Coronavirus/fisiologia , Infecções por Coronavirus/epidemiologia , Planeta Terra , Exobiologia , Meio Ambiente Extraterreno , Interações Hospedeiro-Patógeno/fisiologia , Humanos , Pandemias , Pneumonia Viral/epidemiologia
9.
Nat Commun ; 11(1): 5184, 2020 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-33056977

RESUMO

The global monsoon is characterised by transitions between pronounced dry and wet seasons, affecting food security for two-thirds of the world's population. Rising atmospheric CO2 influences the terrestrial hydrological cycle through climate-radiative and vegetation-physiological forcings. How these two forcings affect the seasonal intensity and characteristics of monsoonal precipitation and runoff is poorly understood. Here we use four Earth System Models to show that in a CO2-enriched climate, radiative forcing changes drive annual precipitation increases for most monsoon regions. Further, vegetation feedbacks substantially affect annual precipitation in North and South America and Australia monsoon regions. In the dry season, runoff increases over most monsoon regions, due to stomatal closure-driven evapotranspiration reductions and associated atmospheric circulation change. Our results imply that flood risks may amplify in the wet season. However, the lengthening of the monsoon rainfall season and reduced evapotranspiration will shorten the water resources scarcity period for most monsoon regions.


Assuntos
Dióxido de Carbono/metabolismo , Modelos Teóricos , Chuva , Recursos Hídricos , Vento , Atmosfera/química , Austrália , Ciclo do Carbono , Dióxido de Carbono/análise , Mudança Climática , Planeta Terra , Inundações , América do Norte , Estações do Ano , América do Sul , Temperatura , Ciclo Hidrológico
10.
Nature ; 586(7831): 680-681, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33057186
11.
Nature ; 587(7832): 42-43, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33057187
12.
Sci Adv ; 6(36)2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32917614

RESUMO

Global strategies to halt the dual crises of biodiversity loss and climate change are often formulated separately, even though they are interdependent and risk failure if pursued in isolation. The Global Safety Net maps how expanded nature conservation addresses both overarching threats. We identify 50% of the terrestrial realm that, if conserved, would reverse further biodiversity loss, prevent CO2 emissions from land conversion, and enhance natural carbon removal. This framework shows that, beyond the 15.1% land area currently protected, 35.3% of land area is needed to conserve additional sites of particular importance for biodiversity and stabilize the climate. Fifty ecoregions and 20 countries contribute disproportionately to proposed targets. Indigenous lands overlap extensively with the Global Safety Net. Conserving the Global Safety Net could support public health by reducing the potential for zoonotic diseases like COVID-19 from emerging in the future.


Assuntos
Biodiversidade , Mudança Climática , Conservação dos Recursos Naturais/métodos , Clima , Planeta Terra , Ecossistema , Humanos , Saúde Pública
14.
Phys Rev Lett ; 125(4): 048104, 2020 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-32794805

RESUMO

The RNA world scenario posits replication by RNA polymerases. On early Earth, a geophysical setting is required to separate hybridized strands after their replication and to localize them against diffusion. We present a pointed heat source that drives exponential, RNA-catalyzed amplification of short RNA with high efficiency in a confined chamber. While shorter strands were periodically melted by laminar convection, the temperature gradient caused aggregated polymerase molecules to accumulate, protecting them from degradation in hot regions of the chamber. These findings demonstrate a size-selective pathway for autonomous RNA-based replication in natural nonequilibrium conditions.


Assuntos
Ecossistema , RNA/química , RNA/genética , Catálise , DNA/química , DNA/genética , DNA/metabolismo , Replicação do DNA , RNA Polimerases Dirigidas por DNA/química , RNA Polimerases Dirigidas por DNA/metabolismo , Planeta Terra , Evolução Molecular , Temperatura Alta , Biossíntese de Proteínas/genética , RNA/metabolismo
15.
PLoS One ; 15(8): e0236732, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32813686

RESUMO

Humans expect downwards moving objects to accelerate and upwards moving objects to decelerate. These results have been interpreted as humans maintaining an internal model of gravity. We have previously suggested an interpretation of these results within a Bayesian framework of perception: earth gravity could be represented as a Strong Prior that overrules noisy sensory information (Likelihood) and therefore attracts the final percept (Posterior) very strongly. Based on this framework, we use published data from a timing task involving gravitational motion to determine the mean and the standard deviation of the Strong Earth Gravity Prior. To get its mean, we refine a model of mean timing errors we proposed in a previous paper (Jörges & López-Moliner, 2019), while expanding the range of conditions under which it yields adequate predictions of performance. This underscores our previous conclusion that the gravity prior is likely to be very close to 9.81 m/s2. To obtain the standard deviation, we identify different sources of sensory and motor variability reflected in timing errors. We then model timing responses based on quantitative assumptions about these sensory and motor errors for a range of standard deviations of the earth gravity prior, and find that a standard deviation of around 2 m/s2 makes for the best fit. This value is likely to represent an upper bound, as there are strong theoretical reasons along with supporting empirical evidence for the standard deviation of the earth gravity being lower than this value.


Assuntos
Gravitação , Modelos Estatísticos , Adulto , Planeta Terra , Feminino , Humanos , Masculino , Adulto Jovem
16.
PLoS One ; 15(8): e0237029, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764793

RESUMO

Paleomagnetic analysis of archaeological materials is crucial for understanding the behavior of the geomagnetic field in the past. As it is often difficult to accurately date the acquisition of magnetic information recorded in archaeological materials, large age uncertainties and discrepancies are common in archaeomagnetic datasets, limiting the ability to use these data for geomagnetic modeling and archaeomagnetic dating. Here we present an accurately dated reconstruction of the intensity and direction of the field in Jerusalem in August, 586 BCE, the date of the city's destruction by fire by the Babylonian army, which marks the end of the Iron Age in the Levant. We analyzed 54 floor segments, of unprecedented construction quality, unearthed within a large monumental structure that had served as an elite or public building and collapsed during the conflagration. From the reconstructed paleomagnetic directions, we conclude that the tilted floor segments had originally been part of the floor of the second story of the building and cooled after they had collapsed. This firmly connects the time of the magnetic acquisition to the date of the destruction. The relatively high field intensity, corresponding to virtual axial dipole moment (VADM) of 148.9 ± 3.9 ZAm2, accompanied by a geocentric axial dipole (GAD) inclination and a positive declination of 8.3°, suggests instability of the field during the 6th century BCE and redefines the duration of the Levantine Iron Age Anomaly. The narrow dating of the geomagnetic reconstruction enabled us to constrain the age of other Iron Age finds and resolve a long archaeological and historical discussion regarding the role and dating of royal Judean stamped jar handles. This demonstrates how archaeomagnetic data derived from historically-dated destructions can serve as an anchor for archaeomagnetic dating and its particular potency for periods in which radiocarbon is not adequate for high resolution dating.


Assuntos
Arqueologia/métodos , Planeta Terra , Campos Magnéticos , Materiais de Construção/análise , Materiais de Construção/história , Fogo/história , Pisos e Cobertura de Pisos/história , História Antiga , Humanos , Israel , Colapso Estrutural/história , Fatores de Tempo , Guerra/história
17.
Proc Natl Acad Sci U S A ; 117(33): 19760-19766, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32747528

RESUMO

Strata from the Ediacaran Period (635 million to 538 million years ago [Ma]) contain several examples of enigmatic, putative shell-building metazoan fossils. These fossils may provide insight into the evolution and environmental impact of biomineralization on Earth, especially if their biological affinities and modern analogs can be identified. Recently, apparent morphological similarities with extant coralline demosponges have been used to assign a poriferan affinity to Namapoikia rietoogensis, a modular encrusting construction that is found growing between (and on) microbial buildups in Namibia. Here, we present three-dimensional reconstructions of Namapoikia that we use to assess the organism's proposed affinity. Our morphological analyses, which comprise quantitative measurements of thickness, spacing, and connectivity, reveal that Namapoikia produced approximately millimeter-thick meandering and branching/merging sheets. We evaluate this reconstructed morphology in the context of poriferan biology and determine that Namapoikia likely is not a sponge-grade organism.


Assuntos
Fósseis/anatomia & histologia , Animais , Evolução Biológica , Planeta Terra , Meio Ambiente , Fósseis/história , História Antiga , Imageamento Tridimensional , Namíbia
18.
Nat Commun ; 11(1): 3832, 2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32737315

RESUMO

Tropical ectotherms are hypothesized to be vulnerable to environmental changes, but cascading effects of organismal tolerances on the assembly and functioning of reef fish communities are largely unknown. Here, we examine differences in organismal traits, assemblage structure, and productivity of cryptobenthic reef fishes between the world's hottest, most extreme coral reefs in the southern Arabian Gulf and the nearby, but more environmentally benign, Gulf of Oman. We show that assemblages in the Arabian Gulf are half as diverse and less than 25% as abundant as in the Gulf of Oman, despite comparable benthic composition and live coral cover. This pattern appears to be driven by energetic deficiencies caused by responses to environmental extremes and distinct prey resource availability rather than absolute thermal tolerances. As a consequence, production, transfer, and replenishment of biomass through cryptobenthic fish assemblages is greatly reduced on Earth's hottest coral reefs. Extreme environmental conditions, as predicted for the end of the 21st century, could thus disrupt the community structure and productivity of a critical functional group, independent of live coral loss.


Assuntos
Antozoários/fisiologia , Biodiversidade , Peixes/fisiologia , Modelos Estatísticos , Adaptação Fisiológica , Animais , Biomassa , Recifes de Corais , Planeta Terra , Ecossistema , Peixes/classificação , Cadeia Alimentar , Temperatura Alta , Oriente Médio , Oceanos e Mares
19.
Science ; 369(6507): 1058, 2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32855327
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