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Although it is not known when or where life on Earth began, some of the earliest habitable environments may have been submarine-hydrothermal vents. Here we describe putative fossilized microorganisms that are at least 3,770 million and possibly 4,280 million years old in ferruginous sedimentary rocks, interpreted as seafloor-hydrothermal vent-related precipitates, from the Nuvvuagittuq belt in Quebec, Canada. These structures occur as micrometre-scale haematite tubes and filaments with morphologies and mineral assemblages similar to those of filamentous microorganisms from modern hydrothermal vent precipitates and analogous microfossils in younger rocks. The Nuvvuagittuq rocks contain isotopically light carbon in carbonate and carbonaceous material, which occurs as graphitic inclusions in diagenetic carbonate rosettes, apatite blades intergrown among carbonate rosettes and magnetite–haematite granules, and is associated with carbonate in direct contact with the putative microfossils. Collectively, these observations are consistent with an oxidized biomass and provide evidence for biological activity in submarine-hydrothermal environments more than 3,770 million years ago. Perhaps the earliest known signs of life have been found in Quebec, where features such as haematite tubes suggest that filamentous microbes lived around hydrothermal vents at least 3,770 million years ago. Early life in hydrothermal vents (Dodd 21377, Biology Article, Henry Gee) Hydrothermal vents on the sea floor have been thought to be some of the earliest habitable environments on the planet. Now Matthew Dodd et al . suggest that possible signatures of life in and around hydrothermal vents at least 3,770 million years ago could represent the earliest evidence for life on Earth. Jasper and carbonate rocks from northern Quebec, Canada preserve features thought to indicate the presence of filamentous microorganisms. These features include haematite tubes that preserve morphologies that are indicative of microbial activity in much younger rocks.

Phosphorus is a limiting nutrient that is thought to control oceanic oxygen levels to a large extent 1 – 3 . A possible increase in marine phosphorus concentrations during the Ediacaran Period (about 635–539 million years ago) has been proposed as a driver for increasing oxygen levels 4 – 6 . However, little is known about the nature and evolution of phosphorus cycling during this time 4 . Here we use carbonate-associated phosphate (CAP) from six globally distributed sections to reconstruct oceanic phosphorus concentrations during a large negative carbon-isotope excursion—the Shuram excursion (SE)—which co-occurred with global oceanic oxygenation 7 – 9 . Our data suggest pulsed increases in oceanic phosphorus concentrations during the falling and rising limbs of the SE. Using a quantitative biogeochemical model, we propose that this observation could be explained by carbon dioxide and phosphorus release from marine organic-matter oxidation primarily by sulfate, with further phosphorus release from carbon-dioxide-driven weathering on land. Collectively, this may have resulted in elevated organic-pyrite burial and ocean oxygenation. Our CAP data also seem to suggest equivalent oceanic phosphorus concentrations under maximum and minimum extents of ocean anoxia across the SE. This observation may reflect decoupled phosphorus and ocean anoxia cycles, as opposed to their coupled nature in the modern ocean. Our findings point to external stimuli such as sulfate weathering rather than internal oceanic phosphorus–oxygen cycling alone as a possible control on oceanic oxygenation in the Ediacaran. In turn, this may help explain the prolonged rise of atmospheric oxygen levels. Reconstruction of oceanic phosphorus concentrations during a large negative carbon-isotope excursion co-occurring with global oceanic oxygenation and evolution of some of Earth’s earliest animals suggests that decoupled phosphorus and ocean anoxia cycles during the Ediacaran may have prolonged the rise of atmospheric oxygen.

Enhanced continental phosphorus (P) input into the oceans has been proposed as a potential trigger for the 1.57 Ga oxygenation event; however, uncertainty remains due to the absence of direct evidence for seawater P concentrations. Here, we investigate shallow marine carbonate rocks of the Gaoyuzhuang Formation in the North China Platform, using the carbonate‐associated phosphate (CAP) proxy to directly reconstruct seawater P levels at that time. Two significant CAP/(Ca + Mg) increases correspond with rises in I/(Ca + Mg) during the oxygenation event suggesting that elevated seawater P concentrations were important in triggering the oxygenation event. Furthermore, a concurrent positive shift in εNd(t) values from −12.3 to −0.9 suggests that a transition in weathering source rocks from intermediate to mafic lithologies significantly contributed to the elevated P fluxes to the oceans during the oxygenation event. This study provides new insights into assessing seawater P levels and their role in the mid‐Proterozoic oxygenation events. Plain Language Summary Phosphorus (P), as a bio‐limiting nutrient for marine organisms, influences primary productivity, organic carbon burial, and therefore the redox conditions of the atmosphere‐ocean system on geological timescales. Previous studies have linked the transient oxygenation event at ∼1.57 Ga to an increase in oceanic P concentrations. However, uncertainty persists due to a lack of direct evidence for seawater P concentrations. Here, we investigate shallow marine carbonate rocks of the Gaoyuzhuang Formation in the North China Platform, using the carbonate‐associated phosphate (CAP) proxy to reconstruct seawater P levels at that time. The results revealed two significant increases in seawater P concentrations contemporaneously with evidence for increasing dissolved oxygen levels during the oxygenation event, suggesting that elevated seawater P concentrations may have played a crucial role in triggering this oxygenation event. Furthermore, a transition in weathering source rocks—from intermediate with relatively low P content to mafic with relatively high P content—has been identified, which likely contributed significantly to the elevated P levels during the oxygenation event. This study provides new insights into the assessment of seawater P levels and their significance during the mid‐Proterozoic oxygenation events. Key Points Carbonate‐associated phosphate (CAP) is used to track seawater phosphorus (P) levels during the 1.57 Ga oxygenation event Two significant CAP increases corresponding with rises in I/(Ca + Mg) implicating P as a driver of rising O2 levels A positive shift in εNd(t) shows enhanced P influx into seawater from the weathering of intermediate to mafic source rocks

The Great Oxidation Event (GOE) represents a major increase in atmospheric O 2 concentration between ca. 2430 and 2060 million years ago, culminating in the permanent shift to an oxygenated atmosphere. It’s causes remain debated. Here we use the carbonate-associated phosphate (CAP) proxy to reconstruct oceanic phosphorus concentrations during the GOE from globally distributed sedimentary rocks. We find that the CAP and the inorganic carbon isotope composition of marine sediments co-varied during the GOE, suggesting synchronous fluctuations in marine phosphorus, biological productivity, and atmospheric O₂. Biogeochemical modelling shows that transient increases in P bioavailability can raise oxygenic primary production and organic carbon burial, yielding isotopically heavy seawater inorganic carbon and reproducing the observed patterns. Consequently, geochemical and modelling data together suggest that P availability was a likely contributor to the rapid oxygenation of Earth during the GOE. Phosphorus locked in ancient marine carbonates shows that ocean phosphorus rose and fell with atmospheric oxygen during the Great Oxidation Event, Earth’s first major oxygenation. Models suggest brief nutrient pulses could have accelerated oxygen production

The cycling of iron and organic matter (OM) is thought to have been a major biogeochemical cycle in the early ferruginous oceans which contributed to the deposition of banded iron formations (BIF). However, BIF are deficient in OM, which is postulated to be the result of near-complete oxidation of OM during iron reduction. We test this idea by documenting the prevalence of OM in clays within BIF and clays in shales associated with BIF. We find in shales >80% of OM occurs in clays, but <1% occurs in clays within BIF. Instead, in BIF OM occurs with 13 C-depleted carbonate and apatite, implying OM oxidation occurred. Conversely, BIF which possess primary clays would be expected to preserve OM in clays, yet this is not seen. This implies OM deposition in silicate-bearing BIF would have been minimal, this consequently stifled iron-cycling and primary productivity through the retention of nutrients in the sediments. Banded iron formations could have formed in the early oceans due to microbial metabolism. Here Dodd and colleagues find little organic carbon in these formations, indicating microbial iron cycling was minimal and could have limited the recycling of important nutrients to overlying waters.

Mass extinctions in the early Palaeozoic have been attributed to global climate change and ocean anoxia with elevated phosphorus (P) proposed as a key driver. However, this hypothesis has lacked geochemical support due to the absence of proxies that can reconstruct changes in marine P availability. Focusing on the Late Ordovician Mass Extinction (LOME) and the Late Devonian Mass Extinction (LDME), we present carbonate-associated phosphate (CAP) data from seven globally distributed sections, providing a proxy record for seawater P variation across these events. Our data reveal short-lived, globally coherent P pulses that coincided with both events. These transient P surges align with biodiversity loss, widespread anoxia, and seawater temperature declines, suggesting a link between P flux, ocean anoxia, and global climate shifts, as supported by biogeochemical model results. These findings provide an empirical connection between brief marine P pulses and ecological crises during the LOME and LDME.

In randomized controlled clinical trials, composite outcomes are often used to study treatment effects. This approach is popular because it increases the number of observed events, enhancing statistical power while reducing the required patient sample size. However, composite outcomes do not provide insight into the effect of individual endpoints. This becomes particularly relevant when mortality is combined with less critical but clinically relevant endpoints or when the clinical importance of individual endpoints varies significantly. As a result, interpreting composite outcomes can be challenging. This narrative review introduces the win ratio (WR), a method for prioritizing individual endpoints within a composite outcome. The WR offers an alternative to composite outcomes by considering the clinical importance of each component and prioritizing the most critical endpoint, such as death, over less significant events. Despite the popularity of the WR among cardiovascular trialists, this approach has not been extensively used in other areas of clinical research. We contend, that perioperative and periprocedural researchers could consider the WR and related approaches when the outcomes of interest are not of similar clinical importance. To this end, understanding the benefits and limitations of the WR will be essential to exploit its benefits, while avoiding potential misuses of the technique.

A crossed bow-tie antenna design for S- and C-Band (2.44–7.62 GHz) with a peak gain of 7.29 dBi is presented to achieve wideband radiation efficiency greater than 90% and circular polarization with a single feed point. The polarization of the antenna is modeled by the input admittance of crossed bow-ties, and the model predictions are validated by experiments. A wideband matching network is designed to be tightly integrated with the antenna and produce a 103% impedance bandwidth. The matching network is decomposed into an equivalent circuit model, and an analysis is presented to demonstrate the principles of the matching network design. A prototype of the optimized antenna design is fabricated and measured to validate the analysis.

The Ediacaran–Cambrian Phosphogenic Episode is the Earth’s first true phosphogenic event and resulted in worldwide phosphate deposits, which occurred during the processes of the Neoproterozoic Oxygenation Event. The Ediacaran Doushantuo Formation (ca. 635–551 Ma) of Weng’an area in central Guizhou, South China, contains two economic phosphorite beds (the Lower and Upper Phosphorite Beds). This paper presents a detailed stratigraphic, sedimentological and mineralogical study of multiple outcrop and drill core sections of the Doushantuo Formation across the Weng’an area, and identified 11 lithofacies and 4 types of phosphatic grains. Significant differences in lithofacies and grain types between the upper and lower phosphate deposits are observed, indicating that the two sets of phosphate deposits are the products of two distinct phosphogenic processes. The Lower Phosphorite Bed mainly consists of banded and laminated phosphorites, contains micro-oncoids formed by microbially-mediated precipitation and peloids formed by in-situ chemically oscillating reactions, indicating a biochemical and chemical enrichment of phosphorus to sediments during the Early Ediacaran Period. The Upper Phosphorite Bed is mainly composed of carbonaceous, massive, and stromatolitic phosphorites, contains bioclasts (phosphatized spheroidal fossils), and intraclasts formed by hydrodynamic agitation, suggesting that the major accesses of phosphorus to sediments were the remineralization of organic P. Deposition of the two economic phosphorite beds was controlled by two sea-level cycles. Such differences have also been documented in contemporaneous phosphate-bearing successions in Brazil and Mangolia, indicating a significant shift in global phosphogenic mechanism during the early and middle Ediacaran, which may be due to the changes in redox conditions in seawater, associated with the Neoproterozoic Oxygenation Event. These regional active P-cycle processes could produce more free oxygen, which may have contributed to the upcoming Phanerozoic global oxidation.