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We report a sudden explosive rise in abundance off southeastern China of a fish species that is hypoxia-tolerant, Bombay duck (Harpadon nehereus, Family Synodontidae), belonging to an Order (the Aulopiformes) encompassing overwhelmingly deep-sea fishes, but which predominantly occurs in coastal water. We suggest that this is made possible by the very high water content of its muscle and other tissues (about 90%, vs 75–80% for other coastal fish), which reduces its oxygen requirements and allows it to outcompete other fish in low-oxygen neritic and estuarine waters. We suggest that the extent to which this drastic shift in abundance and in the resulting community structure in a very extensive and extremely important coastal marine ecosystem offer evidence of growth of ocean deoxygenation along the western edge of the North Pacific Ocean. Also, we suggest that this episode may represent an instructive example of similar disruptions of established marine biological community structures and interlinked life support and natural resource systems that may be expected to emerge under current global trends of climate/environmental change. [ABSTRACT FROM AUTHOR]

A rapid warming event known as the pre-onset excursion (POE) occurred prior to the Paleocene-Eocene Thermal Maximum (PETM). It is less well studied compared to the PETM due to the limited number of well-resolved records globally despite its importance in shaping the subsequent PETM. Shallow marine environments, particularly in low latitudes, are insufficiently documented despite their significant influence on heat and moisture distribution. Here we report high temporal resolution geochemical and magnetic susceptibility records from a well-preserved shallow marine Kuzigongsu section in the Tarim Basin in China to reconstruct the paleoenvironment of the eastern Tethys during the POE. Changes in chemical weathering proxies (e.g. , chemical index of alteration [CIA] and Rb/Sr) suggest chemical weathering intensification occurred after the POE. Higher enrichment factors of P, Ba, Ni, and Cu support increased primary productivity due to enhanced river runoff and nutrient input, which aligns with the observed rise in magnetic susceptibility. Concurrently, the eastern Tethys experienced bottom water deoxygenation, which is supported by redox-sensitive proxies (e.g. , elevated enrichment factors of U and V, and low Mn* values). Increased δ15N org values provide additional evidence of enhanced reduction processes due to increased productivity, attributed to enhanced denitrification and 15N enrichment in seawater's NO 3 − reservoir. The carbon isotope excursion during the POE recovers significantly faster than that during the PETM yet coincides with lingering environmental impacts that are also globally reported for the PETM. These paleoenvironmental proxies reflect notable changes in chemical weathering, ocean productivity, and redox conditions of the eastern Tethys region, potentially setting the stage for the anomalously impactful PETM. • We report new δ15N org and magnetic susceptibility data across the POE from the eastern Tethys. • δ15N org data and weathering proxies support enhanced chemical weathering and ocean deoxygenation. • The paleoenvironmental perturbation during the POE is significant, although smaller than the PETM. [ABSTRACT FROM AUTHOR]

The purpose of this review is to present an overview of the patent landscape for catalysts used in hydrogenation reactions. Based on patent data extracted from PatBase®, we use predefined patent classifications as well as a keyword‐based search for our analyses. The results indicate that the number of patent families that protect heterogeneous catalysts grows twice as fast as that for their homogeneous counterparts. Furthermore, the data show a shift towards abundant and non‐toxic elements in heterogeneous catalysis, while the noble metals continue to dominate the patent landscape of homogeneous catalysis. A subsequent geographical analysis reveals that the high growth rates in heterogeneous catalysis, especially for nickel and iron, are driven by China. Conversely, patenting activities with regard to homogeneous catalysts mainly take place in the USA, the EU, and Japan. The subsequent keyword‐based search illustrates the continuous industrial relevance of enantioselective hydrogenation and transfer hydrogenation, as well as the rapidly increasing body of patents in hydrodeoxygenation. Setting these finding into context, we present and apply two concepts that are commonly used in patent analyses, namely the technology life cycle and the S‐curve. We conclude that hydrogenation catalysis has not reached its peak economic relevance yet and will continue to spark valuable patents and innovations in the future. [ABSTRACT FROM AUTHOR]

The Paleocene – Eocene Thermal Maximum (PETM; ∼56 Ma) represents a rapid and sustained climatic perturbation that lasted for ∼170 kyr and coincided with the emplacement of the North Atlantic Igneous Province (NAIP). Global average temperature increased by 5 to 9 °C, which was likely triggered by a rapid emission of 13C-depleted CO 2. Numerous sites from the deep oceans have been studied for the PETM, but subtropical shallow-water eastern Tethys remains poorly understood despite its importance in regulating heat and moisture transport. Prior studies on calcareous nannofossil biostratigraphy and stable isotopes of marine carbonates confirmed the occurrence of the PETM in the Tarim Basin of the eastern Tethys in northwestern China. Here we present new, high–resolution major, trace and rare earth element geochemical data, and clay mineral records at the Kuzigongsu section in the Tarim Basin to assess the biogeochemical responses of the eastern Tethys to climatic forcings across the PETM. Chemical weathering proxies (chemical index of alteration [CIA], chemical index of weathering [CIW], plagioclase index of alteration [PIA], and Rb/Sr) support an enhanced terrestrial input shortly after the PETM onset, possibly due to intensified chemical weathering. Furthermore, clay mineral assemblage is dominated by illite and illite/smectite during the PETM, implying increased physical weathering. The PETM is also characterized by an increase in nutrient-sensitive elements such as P, Ni, and Cu and higher abundance of nutrient–sensitive calcareous nannofossils, suggesting an intensification of marine primary productivity. Meanwhile, the Tarim Basin may have encountered episodic bottom water deoxygenation supported by an increase in the enrichment factor of redox–sensitive elements such as U and V. The integrated geochemical proxy records suggest that the eastern Tethys has encountered profound ecosystem stress imposed by elevated nutrient fluxes and ocean deoxygenation, which may have been amplified by simultaneously intensified chemical and physical weathering during the PETM. • We reported a new high–resolution geochemical record from the understudied eastern Tethys. • We found evidence of enhanced chemical weathering, increased primary productivity, and ocean deoxygenation. • Clay minerals support enhanced hydrological cycle during the PETM in the eastern Tethys. [ABSTRACT FROM AUTHOR]

Barkinite is only found in Chinese coal and it has not been recognized by the International Committee for Coal and Organic Petrology. The hydrocarbon-generated ability of barkinite is still vague. In this work, the hydrocarbon-generated potential of barkinite and vitrinite from Mingshan coal mine in the South of China was investigated by Rock-Eval pyrolysis and solvent extraction analysis. Barkinite and vitrinite were separated by the density gradient centrifugation method. The results showed that barkinite had high hydrocarbon generation potential, as reflected by evidently high hydrogen index (HI) values (607.0 mg HC g−1 TOC), S1 + S2 values (297.4-475.7 mg HC g−1), total hydrocarbon yield (23.55-30.20 mass%), and H/C atomic ratio (1.01). Both the S1 + S2 and HI values of barkinite are higher than those of vitrinite. For barkinite, the range values of the temperature at which the S2 peak is at its maximum (Tmax) are from 437 to 446 °C, and for vitrinite are 436 °C. The extraction results represented that the total hydrocarbon yield of barkinite is from 23.55 to 30.20 mass%, while that of vitrinite is 23.99 mass%. This indicated that the high hydrocarbon generation ability of bark coal is greatly controlled by high barkinite content and followed by vitrinite content. [ABSTRACT FROM AUTHOR]

• Hypolimnetic deoxygenation intensified in Lake Fuxian since 1994. • Eutrophication since 1986 did not promote hypolimnetic deoxygenation. • Greater catchment disturbance in the 1950s and 1960s did not alter hypolimnetic deoxygenation. • Intensification of hypolimnetic deoxygenation was driven mainly by climate warming. In monomictic lakes, the potential intensification of hypolimnetic deoxygenation due to human activities and climate change threatens lake ecosystems and water quality. Understanding the trends and mechanisms of hypolimnetic deoxygenation would allow for the adaptive management of monomictic lakes. This study investigated the trends and drivers of hypolimnetic deoxygenation in Lake Fuxian (a monomictic lake in south-western China) over the past 150 years using paleolimnological evidence and historical records. Analysis of enrichment factors for molybdenum (Mo), uranium (U), and vanadium (V), and ratios of U/thorium (Th), pristane (Pr)/phytane (Ph), and total organic carbon (TOC)/total phosphorus (TP) in a dated sediment core indicated that the extent of hypolimnetic deoxygenation was relatively low before 1994 and increased substantially thereafter. Nutrient monitoring records and sediment n -alkane proxies indicated notable eutrophication of the lake since 1986 and a greater degree of human disturbance in the catchment between 1951 and 1967. Due to their asynchronous occurrence, eutrophication and catchment disturbance could not be the major drivers of hypolimnetic deoxygenation. Interestingly, climate records indicated that the local ambient temperature exhibited similar trends to that of hypolimnetic deoxygenation, including markedly higher temperatures after 1994. This implies that prolonged water column stratification due to climate warming could have promoted hypolimnetic deoxygenation by limiting oxygen exchange between the upper and lower water columns. In comparing the results with those of Lake Erhai, another monomictic lake with contrasting morphology and hydrology characteristics, we found that the low surface area/depth ratio and long water residence time in Lake Fuxian enable dissolved oxygen of the lake hypolimnion vulnerable to temperature over the lake. [ABSTRACT FROM AUTHOR]

Long-flame coal is a typical low-ranked coal that is not fully utilized and has a huge global reserve. High-content oxygen is a significant negative factor for low-rank coal utilization. The TG–FTIR–GC/MS method was applied to investigate the migration behavior of oxygen and the variation in the properties of Chinese long-flame coal during low-temperature pyrolysis. It was found that the oxygen migration ratios in long-flame coal toward gas and tar were 47.7 and 5.2%, respectively, at 550 °C, that the initial oxygen migration temperatures of hydroxyl, carboxyl, carbonyl and ether bonds were 500, 200, 300 and 350 °C, respectively, that the decomposition rates were 8.2, 90, 99.2 and 86% at 550 °C, respectively, that the oxygen in gas existed mainly in the form of CO2 and CO, and that the oxygen in tar existed mainly in the form of phenolic compounds. The further removal of oxygen was due to the decomposition of hydroxyl and a small amount of stable ether bonds. Furthermore, deoxygenation suggested that the decrease in oxygen had a positive effect on coal liquefaction and resulted in a decrease in its hydrophilicity. [ABSTRACT FROM AUTHOR]

Coastal areas can represent an ecological transition zone with the function of biodiversity conservation, and good water quality is fundamental to maintaining this function. In this study, we analyzed data from 2011 to 2020 to reveal the variation in dissolved oxygen (DO) and the aquatic biological response in China's coastal seas. Results showed that DO in coastal waters exhibited an upward trend from 2011 to 2020 because of reduction in terrestrial anthropogenic pollutant (TAP) input. In comparison with DO in other seas, the DO content in the East China Sea was lower owing to higher TAP input, i.e., the proportion of DO of <5 mg L−1 accounted for approximately 60% of the total. Species numbers, density, and the species diversity index of phytoplankton, zooplankton, and macrobenthos were different in the different sea areas because phytoplankton, zooplankton, and macrobenthos have different responses to changes in DO. In comparison with the species numbers of zooplankton and macrobenthos, the species numbers of phytoplankton were more significantly related to DO, and showed a negative linear relationship with a better DO environment (DO ≥ 5 mg L−1; r2 = 0.39, p < 0.01) and positive correlation with a poor DO environment (DO < 3 mg L−1; r2 = 0.52, p < 0.01). A better DO environment is conducive to increased density of macrobenthos. Studies have shown that a good DO environment contributes to coastal ecosystem health, and continuous control of TAP input is an effective means of ensuring DO recovery. [Display omitted] • DO in the coastal seas has improved from 2011 to 2020. • East China Sea has worse DO than that in other seas due to more TAP input. • The responses of aquatic organisms to DO changes were different. • Further control TAP input benefit for DO recovery and coastal ecosystem protection. [ABSTRACT FROM AUTHOR]

The efficacy of a BWMS with filtration + membrane separation + deoxygenation technology in treating ballast water was investigated under marine operational circumstances in five shipboard tests. The shipboard tests were carried out between August 2020 and March 2021 onboard a bulk carrier JIN HAI HUA, which sailed between Mawei, Qinhuangdao and Caofeidian in China throughout spring, summer, and fall season. The discharge results in all five tests met the D-2 standard in IMO BWMS Code, with the shortest holding time of less than three days. The BWMS does not involve application of chemicals or generation of by-products, and is considered to be an appropriate choice for certain types of ships. • Filtration + membrane separation + deoxygenation technology is a physical process that can be considered as a new green ballast water treatment process. • The discharge results in all five tests showed compliance with the D-2 standard. • These five shipboard tests throughout three different sea areas and seasons at three diverse ports along the coastline of China. • The requirement of the minimum phytoplankton in the uptake water stipulated by IMO is a challenge. [ABSTRACT FROM AUTHOR]

Permian chert successions were geographically extensive, spanning from the palaeoequator to the northern high latitudes. Large-scale chert production was abruptly terminated in the latest Permian, resulting in a multi-million-year "chert gap" in the Early Triassic. In order to constrain the tempo of chert production changes and understand their nature, we combine proxy data with Si box model analyses and focus on the Talung Formation of South China—the most representative Upper Permian siliceous unit in the equatorial Tethys. Two deepwater sections from the northern margin of the Yangtze Platform were investigated, showing that bedded cherts had already become less common in the Clarkina changxingensis conodont zone. The waning of chert production coincided with water column deoxygenation and an increase in carbonate and siliciclastic components in the late Changhsingian. The final collapse of the chert factory in South China predated the negative δ 13 C excursion and climate warming but coincided with a sharp decrease in primary productivity. Together with Si box model output, we suggest that warming-induced expansion of the oceanic dissolved silica inventory (and decrease in burial efficiency) alone cannot maintain a multi-million-year chert gap. Instead, a loss of siliceous biomass during the end-Permian crisis is the primary cause of the Early Triassic chert demise. • Proxy data and a Si box model are combined to understand the demise of cherts at the end of the Permian. • In the eastern Tethys, bedded cherts are already less common in the C. changxingensis conodont Zone. • The decrease in chert production coincided with primary productivity collapse and water column deoxygenation. • A loss of siliceous biomass is the primary cause of the Early Triassic chert gap. • Warming-induced decrease in burial efficiency alone cannot explain the chert gap. [ABSTRACT FROM AUTHOR]

• DOM sources and transformations were investigated along a river-reservoir continuum. • Deoxygenation enhanced hypolimnetic refractory DOM production and lateral export. • Inland dark waters are hotspots for microbial carbon transformation and turnover. Global impoundment of river systems represents a major anthropogenic forcing to carbon cycling in reservoirs with seasonal thermal stratification. Currently, a quantitative and mechanistic understanding of how hypolimnetic deoxygenation in stratified reservoirs alters dissolved organic matter (DOM) cycling and lateral transport along the river continuum remains unresolved. Herein, we used optical and high-resolution mass spectrometric analyses to track seasonal and spatial compositional changes of DOM from a large, subtropical impounded river in southeast China. Aliphatic compounds were contributed by algal blooms to epilimnetic DOM during the spring/summer and by baseflow to the overall DOM pool during low-discharge periods. Deoxygenation-driven hypolimnetic mineralization enhanced in situ production of bio-refractory molecules and humic-like fluorescent DOM (FDOM H) by utilizing bio-labile DOM and settling biogenic particles during periods of stratification. Production efficiency of hypolimnetic FDOM H was 159–444% higher than that of the global dark ocean, and was strongly regulated by temperature and possibly substrate supply. The in situ production rate of hypolimnetic FDOM H was four to five orders-of-magnitude higher than the dark ocean, with much faster turnover rates in dark inland waters versus the dark ocean. Collectively, these findings indicate that the hypolimnion is a hotspot for microbial carbon transformations, and hence an important source and pool of refractory DOM in aquatic systems. The lateral FDOM H flux increased 10.8–32.1% due to hypolimnetic reservoir release during periods of stratification, highlighting the importance of incorporating hypolimnetic carbon transformations into models for carbon cycling of inland waters and the land-sea interface. [Display omitted] [ABSTRACT FROM AUTHOR]

Understanding the biogeochemical effects of global warming on large lakes is central to managing aquatic resources. The Paleocene-Eocene Thermal Maximum (PETM) presents an excellent paleo-analog for potential impacts arising from current global warming. e, we reconstructed dynamic redox changes in a large lake located in modern Central China during the PETM, using carbonate-associated sulfate sulfur and oxygen isotopes. Three major anoxic episodes (AE) associated with intensive microbial sulfate reduction (MSR) were identified, as indicated by higher sulfur and oxygen isotope compositions, and/or decreased sulfate contents. Thermal stratification in the lake was the likely main cause of the anoxia and associated changes in sulfur geochemical cycles. The first two AEs occurred during the initial stage of PETM. They are characterized by low sulfate and total organic carbon-minus-black carbon (TOC-BC) contents, suggestive of low biological productivity related to limited nutrient cycling in a stratified and anoxic water mass. The third AE occurred during the peak of the PETM. It was characterized by extremely low sulfate and high TOC-BC contents, possibly the product of increased near-surface productivity coupled with anoxia in the lower water column. An intensified hydrological cycle triggered by severe warming may have enhanced terrestrial nutrient fluxes to the lake, leading to increased surficial lake productivity. Upward expansion of the anoxic/sulfidic zone, however, may have suppressed the lake ecosystem by contracting its livable space. Our results suggest that current global warming could trigger similar ecological stress in large lakes. [Display omitted] • Three anoxic episodes arose during the PETM in a lake located in modern central China. • Warming induced long-term year-round lake stratification and a large euxinic zone. • Euxinic water caused lake ecological crises by inhibiting intra-lake nutrient cycling. [ABSTRACT FROM AUTHOR]

To meet the increasing stringent discharge standards, many wastewater treatment plants (WWTPs) are impelled to execute tertiary treatment, among which advanced nitrogen removal is still the key. An effective alternative for advanced nitrogen removal is sequencing biofilm batch reactor (SBBR), whose performance is closely related to dissolved oxygen (DO). In this study, the effects of deoxygenation pretreatment during anoxic phase and DO adjustment during aerobic phase on performance of double-layer-packed SBBR treating a typical carbon-lacked (COD/TN = 2.0, dominated with ammonium) secondary effluent under low temperature (15 °C) were investigated. It was found that deoxygenation pretreatment via adding sulfite had no significant impact on organics/phosphorus removal or nitrification but significantly improved denitrification. The deoxygenation stimulated nitrite accumulation leading to a higher simultaneous nitrification and denitrification (SND) rate. Similarly, with the increase of DO during aerobic phase, nitrification capacity increased while denitrification intensity decreased. When DO ≥ 3.5 mg/L, total ammonium nitrogen (TAN) in final effluent met the first A standard (GB 18918-2002, China). When DO at 2.5 mg/L, a highest denitrification intensity was observed while neither TAN nor total nitrogen (TN) in final effluent met the discharge standards probably mainly due to low temperature and carbon shortage. Among all the tests, FA and FNA were not the main causes for nitrite accumulation. The above findings might be helpful in guiding practical applications. Image 10259 • Deoxygenation pretreatment significantly improved denitrification intensity. • Deoxygenation stimulated nitrite accumulation leading to a higher SND rate. • Nitrification increased while denitrification decreased with increase of DO. • A highest denitrification intensity was observed at DO of 2.5 mg/L. [ABSTRACT FROM AUTHOR]