Seafloor hydrothermal control over ocean dynamics in Enceladus
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Escalation of caldera unrest indicated by increasing emission of isotopically light sulfur
Calderas are depressions formed by some of the largest volcanic eruptions. Their long-lived inter-eruptive periods are occasionally interrupted by phases of unrest, in which escalating seismicity, ground deformation and gas emissions raise concerns of potential volcano reawakening. However, interpretation of such physico-chemical signals is complicated by few examples of monitored unrest that culminated into eruption and by our fragmentary understanding of the drivers and timescales of caldera reactivation. Here we show that multi-decadal gas observations at the restless Campi Flegrei caldera in Italy record an unprecedented increase in isotopically light sulfur release from fumaroles since 2018. We then use hydrothermal gas equilibria and numerical simulations of magmatic degassing to propose that such a change in sulfur emissions results from decompression-driven degassing of mafic magma at ≥6 km depth, along with some extent of sulfur remobilization from hydrothermal minerals. Examination of a global dataset indicates that, despite the diversity in eruptive behaviour and tectonic setting, increasing sulfur output may be a common process during unrest escalation at calderas generally. Hence, our observations and models of sulfur behaviour may inform interpretations of unrest and hazard assessment at reawakening calderas and hydrothermal active volcanoes worldwide.
Risks of competing discourses of scientific responsibility in global ocean futures
Accelerated innovation in climate-impacted oceans is outpacing standards of scientific responsibility. Standards of responsibility are critical because they shape research agendas, funding flows, scientific practice, and how innovations are regulated. Here, we examine responsibility debates among 243 marine scientists and end-users proposing, trialling and/or implementing 76 innovations for climate-impacted oceans. We identify three distinct discourses: ‘science outside society’, ‘science for society’ and ‘science with society’. Competition within and across these discourses reveals heightened tensions between the need to protect scientific autonomy and freedom, and moral duty to ensure socially just and desirable ocean futures. Without thorough debate and oversight, the wide-reaching power of such unresolved tensions could propel marine science and ocean futures into volatile ethical and moral territory. Better connection and articulation of standards of responsibility with scientific motivations, practices, and funding are key to ensuring the transparency and accountability required to progress equitable and sustainable oceans.
Magnetic hydrochar for sustainable wastewater management
Sustainable wastewater treatment requires economical, high-performance materials. Magnetic hydrochar, synthesized from low-cost feedstocks, combines tunable surface properties and magnetic functionality, enabling efficient pollutant removal, facile magnetic separation, and cost-effectiveness. This review explores recent advancements in the synthesis and application of magnetic hydrochar for wastewater treatment. Magnetic hydrochar is promising for practical wastewater treatment, as demonstrated by sustainability assessments, bridging the gap between cutting-edge technology and practical implementation in environmental remediation.
Marine mammals as indicators of Anthropocene Ocean Health
The current state of marine mammal populations reflects increasing anthropogenic impacts on the global Ocean. Adopting a holistic approach towards marine mammal health, incorporating healthy individuals and healthy populations, these taxa present indicators of the health of the overall Ocean system. Their present deterioration at the animal, population and ecosystem level has implications for human health and the global system. In the Anthropocene, multiple planetary boundaries have already been exceeded, and quiet tipping points in the Ocean may present further uncertainties. Long and short-term monitoring of marine mammal health in the holistic sense is urgently required to assist in evaluating and reversing the impact on Ocean Health and aid in climate change mitigation.
Mechanistic links between intense volcanism and the transient oxygenation of the Archean atmosphere
The Archean Earth was characterized by a persistent reducing atmosphere, while the occurrence of transient atmospheric oxygenation events—whiff of oxygen—has been suggested, the precise nature and causes of which remain elusive. Here we used a biogeochemical model, corroborating the eruption of large igneous provinces as a plausible mechanistic explanation for these transient oxygenation events. Our results show that biogeochemical dynamics induced by eruptions of large igneous provinces could have caused transient increases in atmospheric oxygen levels lasting for more than several million years. Notably, we show that continental growth would have mitigated conditions for transient oxygenation. This may imply that the whiffs during the late Archean infer that the Earth system was approaching a tipping point for the permanent oxidation of the atmosphere. Our results highlight the mechanistic link between planetary volcanic activities and the dynamic evolution of the atmosphere at the dawn of the Great Oxidation Event.
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