Overall ocean health depends critically on dissolved oxygen, which is increasingly impacted by global warming. The Arctic and subarctic regions are experiencing exceptionally rapid warming, known as Arctic amplification, yet its impact on oceanic oxygen remains poorly understood. Here we show that inflowing Atlantic Water (AW) drives deoxygenation in the upper eastern Arctic Ocean and the intermediate layers of the western Arctic Ocean at rates from -0.41 +/- 0.17 to -0.47 +/- 0.07 mu mol kg-1 yr-1, six times the global mean. Amplified Arctic warming is the primary driver, significantly reducing oxygen solubility in the Arctic gateway regions. Rapid subduction and circulation of AW further transmit the deoxygenation signal into Arctic deeper layers, greatly threatening marine ecosystems. Our findings highlight the dominant role of warming Atlantic inflow in shaping the Arctic Ocean oxygen dynamics, indicating that ongoing temperature increases will perpetuate deoxygenation trends and underscoring the need for widespread attention.

Abstract The acidification of coastal waters is distinguished from the open ocean because of much stronger synergistic effects between anthropogenic forcing and local biogeochemical processes. However, ocean acidification research is still rather limited in polar coastal oceans. Here, we present a 16 year (2002–2018) observational dataset in the Chukchi Sea during the rapid sea‐ice melting season to determine the long‐term changes in pH and aragonite saturation state (Ωarag). We found that pH and Ωarag significantly declined in the water column with average rates of −0.0095 ± 0.0027 years−1 and −0.0333 ± 0.0098 years−1, respectively, and are 4–6 times faster than those solely due to increasing atmospheric CO2. We attributed the rapid acidification to the increased dissolved inorganic carbon owing to a combination of ice melt‐induced increased atmospheric CO2 invasion and subsurface remineralization induced by a stronger surface biological production as a result of the increased inflow of the nutrient‐rich Pacific water.

The strong CO2 sink in Arctic Ocean plays a significant role in the global carbon budget. As a high-latitude oceanic ecosystem, the features of sea surface pCO2 and air-sea CO2 flux are significantly influenced by sea ice melt; however, our understanding of pCO2 evolution during sea ice melt remains limited. In this study, we investigate the dynamics of pCO2 during the progression of sea ice melt in the western Arctic Ocean based on data from two cruises conducted in 2010 and 2012. Our findings reveal substantial spatiotemporal variability in surface pCO2 on the Chukchi Sea shelf and Canada Basin, with a boundary along the shelf breaks at depths of 250-500 m isobaths. On the Chukchi Sea shelf, strong biological consumption dominates pCO2 variability. Moreover, in Canada Basin, the pCO2 dynamics are modulated by various processes. During the active sea ice melt stage before sea ice concentration decreases to 15%, biological production through photosynthetic processes and dilution of ice melt water lead to a reduction in DIC concentration and subsequent decline in pCO2. Further, these effects are counteracted by the air-sea CO2 exchange at the sea surface which tends to increase seawater DIC and subsequently elevate surface pCO2. Compared to the pCO2 reduction resulting from biological production and dilution effects, the contribution of air-sea CO2 exchange is significantly lower. The combined effects of these factors have a significant impact on reducing pCO2 during this stage. Conversely, during the post sea ice melt stage, an increase in pCO2 resulting from high temperatures and air-sea CO2 exchange outweighs its decrease caused by biological production. Their combined effects result in a prevailing increase in sea surface pCO2. We argue that enhanced air-sea CO2 uptake under high wind speeds also contributes to the high sea surface pCO2 observed in 2012, during both active sea ice melt stage and post sea ice melt stage. The present study reports, for the first time, the carbonate dynamics and pCO2 controlling processes during the active sea ice melt stage. These findings have implications for accurate estimation of air-sea CO2 fluxes and improved modeling simulations within the Arctic Ocean.

The study of marine microbial communities is crucial for comprehending the distribution patterns, adaptations to the environment, and the functioning of marine microorganisms. Despite being one of the largest biomes on Earth, the bacterioplankton communities in the Northwest Pacific Ocean (NWPO) remain understudied. In this research, we aimed to investigate the structure of the surface bacterioplankton communities in different water masses of the NWPO. We utilized metagenomic sequencing techniques and cited previous 16S rRNA data to explore the distribution patterns of bacterioplankton in different seasons. Our results revealed that Cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria dominated the microbial communities, accounting for over 95% of the total. During spring, we observed significant differentiation in community structure between the different water masses. For instance, Prochlorococcus and Pseudoalteromonas were primarily distributed in the nutrient-deficient subtropical countercurrent zone, while Flavobacteriaceae and Rhodobacteraceae were found in the Kuroshio-Oyashio mixing zone. During summer, the surface planktonic bacteria communities became homogenized across regions, with Cyanobacteria becoming the dominant group (68.6% to 84.9% relative abundance). The metabolic processes of the microorganisms were dominated by carbohydrate metabolism, followed by amino acid transport and metabolism. However, there was a low relative abundance of functional genes involved in carbohydrate metabolism in the Kuroshio-Oyashio mixing zone. The metagenomic data had assembled 37 metagenomic-assembled genomes (MAGs), which belong to Proteobacteria, Bacteroidetes, and Euryarchaeota. In conclusion, our findings highlight the diversity of the surface bacterioplankton community composition in the NWPO, and its distinct geographic distribution characteristics and seasonal variations.

Oceanic uptake of anthropogenic CO2 causes a decrease in seawater pH and aragonite saturation state (Ωarag), a process known as ocean acidification (OA). The western North Pacific is a hotspot for anthropogenic CO2 sinks; however, the spatiotemporal variability of pH and Ωarag and their controlling mechanisms remain unexplored. In this study, we provide high-frequency and high-precision underway measurements of sea surface pCO2 and pH to investigate the distribution and drivers of OA metrics across different hydrochemical gradients in the western North Pacific in late spring 2018, a season with the highest primary production in the year. Our results show that the surface pH reached near air-sea equilibrium in the subtropical zone but gradually increased northward across the Kuroshio Recirculation (KR) zone and peaked in the Kuroshio Extension (KE) zone. We found that sea surface temperature played the most prominent role in regulating pH, which was also counteracted by the effects of air–sea gas exchange and vertical mixing. In contrast, the distribution of Ωarag largely mirrored the pH and was governed by air–sea gas exchange and vertical mixing, the effects of which on Ωarag were enhanced by temperature. Biological activity thrived in the KE zone to increase both pH and Ωarag, which further reinforced the latitudinal pattern of pH, but weakened that of Ωarag. These findings are based on direct in situ measurements of pH and improve our understanding of the spatiotemporal variability of OA metrics in the western North Pacific region.

The carbonate chemistry of sea ice plays a critical role in global ocean carbon cycles, particularly in polar regions which are subject to significant climate change-induced sea ice variation. However, less is known about the interaction of carbonate system between sea ice and its adjacent seawaters due to sparse sampling and disparities in reported results. Here we provide an insight into this issue by collecting and measuring dissolved inorganic carbon (DIC) and associated environmental parameters in Arctic sea ice during a cruise in the summer of 2014. Our observations show that DIC in Arctic summer sea ice has a mean concentration of 463.3 ± 213.0 μmol/kg and appears to be controlled mainly by the fraction of brine water in the ice. The low Chl a and nutrients content in sea ice indicate minor contribution of biological uptake to sea-ice DIC in the western Arctic Ocean. The DIC concentration in surface water (<100 m depth) decreased from a mean of 2108.3 ± 45.4 μmol/kg in 1994 to a mean of 2052.4 ± 98.6 μmol/kg in 2014, due to the enhanced sea ice melting that dilutes the DIC concentrations of surrounding seawaters.

Oceanic uptake and storage of anthropogenic CO2 (C-ANT) are regulated by ocean circulation and ventilation. To decipher the storage and redistribution of C-ANT in the western North Pacific, where a major C-ANT sink develops, we investigated the water column carbonate system, dissolved inorganic radiocarbon and ancillary parameters in May and August 2018, spanning the Kuroshio Extension (KE, 35-39 degrees N), Kuroshio Recirculation (KR, 27-35 degrees N) and subtropical (21-27 degrees N) zones. Water column C-ANT inventories were estimated to be 40.5 +/- 1.1 mol m(-2) in the KR zone and 37.2 +/- 0.9 mol m(-2) in the subtropical zone. In comparison with historical data obtained in 2005, relatively high rates of increase of the C-ANT inventory of 1.05 +/- 0.20 and 1.03 +/- 0.12 mol m(-2) yr(-1) in the recent decade were obtained in the KR and subtropical zones, respectively. Our water-mass-based analyses suggest that formation and transport of subtropical mode water dominate the deep penetration, storage, and redistribution of C-ANT in those two regions. In the KE zone, however, both the water column C-ANT inventory and the decadal C-ANT accumulation rate were small and uncertain owing to the dynamic hydrology, where the naturally uplifting isopycnal surfaces make C-ANT penetration relatively shallow. The findings of this study improve the understanding of the spatiotemporal variations of C-ANT distribution, storage, and transport in the western North Pacific.

The Arctic Ocean has experienced rapid warming and sea ice loss in recent decades, becoming the first open-ocean basin to experience widespread aragonite undersaturation [saturation state of aragonite (Ωarag) < 1]. However, its trend toward long-term ocean acidification and the underlying mechanisms remain undocumented. Here, we report rapid acidification there, with rates three to four times higher than in other ocean basins, and attribute it to changing sea ice coverage on a decadal time scale. Sea ice melt exposes seawater to the atmosphere and promotes rapid uptake of atmospheric carbon dioxide, lowering its alkalinity and buffer capacity and thus leading to sharp declines in pH and Ωarag. We predict a further decrease in pH, particularly at higher latitudes where sea ice retreat is active, whereas Arctic warming may counteract decreases in Ωarag in the future.

为了解大亚湾沉积物中重金属分布及污染状况,于2016年8月对大亚湾海域表层沉积物中重金属元素(As、Cd、Cr、Pb、Zn和Cu)展开调查,并将获得的各元素含量与粒度、Fe、Mn和总有机碳(TOC)等相关理化要素进行相关性分析.结果表明:大亚湾沉积物中重金属受陆源输入影响较大,含量基本呈现为沿岸高、湾内低的趋势,总体质量较好,基本符合第一类海洋沉积物质量标准要求;澳头湾和范和港附近海域人类活动密集,重金属含量较高.通过相关性分析结果发现,大亚湾重金属主要来源为岩石的风化和侵蚀、工业污水排放和渔业养殖等;Cu与铁锰氧化物结合性弱于其他元素,在还原性环境中被沉积物吸附形成金属Cu硫化物可能是喜洲岛附近海域Cu元素含量异常高值的原因;作为湾内有机质主要来源的水生浮游生物的生长状态对Cr、Zn和Pb含量影响较大;Cr、As和Pb与粉砂结合为主,Zn与粘土结合为主.

The spatiotemporal variabilities and drivers of ocean acidification (OA) metrics, [H+], pH, and aragonite saturation state (Ωarag) across environmental gradients remain poorly constrained. We use a novel high‐precision measurement of underway pH to investigate the hemispheric‐scale distributions of OA metrics from East Asia to the Arctic Ocean. While temperature and its induced air‐sea gas exchange fundamentally control the OA metrics distributions, we show that biological activity exerts the most prominent but different modifications on pH and Ωarag patterns. Strong photosynthesis counteracts the temperature‐driven pH pattern but reinforces that of Ωarag. Ice melt‐induced dilution in the Arctic Ocean additionally strengthens the Ωarag‐temperature relationship but insignificantly affects [H+] and pH. This study provides the first coherent assessment of comprehensive processes on OA metrics across large spatial regions, and highlights the potential of sea‐ice melt in changing Ωarag distribution, which should be included by Earth system models projecting future climate change.

To examine seasonal and regional variabilities in metabolic status and the coupling of net community production (NCP) and air‐sea CO2 fluxes in the western Arctic Ocean, we collected underway measurements of surface O2/Ar and partial pressure of CO2 (pCO2) in the summers of 2016 and 2018. With a box‐model, we demonstrate that accounting for local sea ice history (in addition to wind history) is important in estimating NCP from biological oxygen saturation (Δ(O2/Ar)) in polar regions. Incorporating this sea ice history correction, we found that most of the western Arctic exhibited positive Δ(O2/Ar) and negative pCO2 saturation, Δ(pCO2), indicative of net autotrophy but with the relationship between the two parameters varying regionally. In the heavy ice‐covered areas, where air‐sea gas exchange was suppressed, even minor NCP resulted in relatively high Δ(O2/Ar) and low pCO2 in water due to limited gas exchange. Within the marginal ice zone, NCP and CO2 flux magnitudes were strongly inversely correlated, suggesting an air to sea CO2 flux induced primarily by biological CO2 removal from surface waters. Within ice‐free waters, the coupling of NCP and CO2 flux varied according to nutrient supply. In the oligotrophic Canada Basin, NCP and CO2 flux were both small, controlled mainly by air‐sea gas exchange. On the nutrient‐rich Chukchi Shelf, NCP was strong, resulting in great O2 release and CO2 uptake. This regional overview of NCP and CO2 flux in the western Arctic Ocean, in its various stages of ice‐melt and nutrient status, provides useful insight into the possible biogeochemical evolution of rapidly changing polar oceans.

In order to make a scientific evaluation of the innovation and entrepreneurship competencies of teachers in industry-oriented higher vocational colleges, against the background of the "industry-education integration", on the theoretical basis of competency and iceberg model, and combined with the inherent characteristics of industry-oriented higher vocational colleges and the status quo of teachers' innovation and entrepreneurship competencies, this paper establishes an index system from two aspects of innovation ability and entrepreneurship ability respectively, including feature competency, technology competency, practice competency and society competency and constructs matrix positioning model for the innovation and entrepreneurship competency evaluation of teachers in industry-oriented higher vocational colleges, so as to provide a reference for solving the shortcomings of teachers in innovation and entrepreneurship and improving the quality of innovation and entrepreneurship education.

根据2013—2014年在钦州湾及其邻近海域获取的夏、秋、冬、春4个季节的环境调查资料,分析了表层海水中溶解态重金属的时空变化特征,并运用主成分分析法研究了影响重金属分布的因素.结果表明,Cu、Pb、Zn、Cd、Cr、Hg、As含量范围分别为0.214～1.510、nd～0.979、0.132～4.160、0.005～0.106、0.014～2.580、0.012～0.049、1.2～2.2μg/dm3,各重金属元素含量均处于历史较低水平;夏、秋季重金属的平均含量依次是As>Cu>Zn>Cr>Pb>Cd>Hg,冬、春季则是As>Zn>Cu>Pb>Cr>Cd>Hg;入海径流量受控于降水,使得雨季时Cu、Zn、Cd、Hg、As的含量通常高于干季;东北季风期间大气沉降可能是Pb含量由夏季到春季逐步增高的主要原因;除夏季Pb、Cd和冬季Pb、Cd、Zn外,其它重金属之间具有显著的同源性.陆源输入是钦州湾及其邻近海域重金属的重要来源,咸淡水混合过程(酸碱度变化及物理混合)是影响重金属分布的最主要因素,潮流作用也是影响重金属分布的重要因素.

To better understand the extent of acidification in the Arctic Ocean, we present pH measurements collected along a shelf-slope-basin transect from the Chukchi Sea shelf to the Chukchi Abyssal Plain (CAP) in the western Arctic Ocean during the summer 2010 Chinese Arctic National Research Expedition (CHINARE) cruise. We observed low pH values in the Chukchi Sea shelf bottom waters (similar to 30 m-bottom) and CAP upper haloline layer (UHL) (100-200 m). In the shelf bottom waters, the pH values were 7.66-8.13, about 0.07-0.68 pH units lower than the surface values of 8.20-8.24. In the CAP subsurface waters, the pH values were 7.85-7.98, about 0.08-0.31 pH units lower than the surface values of 8.20-8.24. Biogeochemical model simulations suggest that remineralized CO2 driven by sea-ice loss is primarily responsible for the low pH values in the bottom waters of the Chukchi Sea (shelf) and the UHL waters of the CAP (basin). Recent sea-ice melt enhanced organic matter production in surface waters and subsequent supported the increased microbial respiration of organic matter in bottom waters. Moreover, low pH bottom waters were flushed into the UHL during winter to sustain the low pH characteristics in the subsurface basin layers. In addition, our simplified model suggests that the thermodynamic effect of pH is small. However, increasing temperature significantly increased aragonite saturation (Omega(arag)) which slowed down the speed of acidification.

The Southern Ocean is the most important carbon sink in the world because of its relatively cold seawater temperature and unique overturning circulation which provides a conduit for atmospheric CO2 to enter into the deep ocean. However, it remains less clear how physical-biogeochemical processes control the carbon source/sink status because of the sparse spatiotemporal coverage of observations in the Southern Ocean, particularly in its coastal areas. The sea surface partial pressure of CO2 (pCO(2)) and related carbonate system parameters were measured in Prydz Bay during the 31st Chinese National Antarctic Research Expedition (CHINARE) cruise in February 2015. Our results showed a contrast spatial pattern of sea surface pCO(2) in the southern and northern regions of the Antarctic Slope Front (ASF), corresponding to their different hydrographic settings. The surface waters over the continental shelf south of the shelf break served as a strong CO2 sink (-35.1 +/- 32.1 mmol C m(-2) d(-1)) due to the enhanced net primary production when sea-ice was absent. The surface waters north of the shelf break were found to be a moderate CO2 sink (-7.0 +/- 5.9 mmol C m(-2) d(-1)) despite the upwelling of CO2-rich subsurface waters. The high wind velocities have contributed to the overall large magnitude of CO2 sink although the average atmospheric pCO(2) was only slightly higher than the sea surface pCO(2) (similar to 237-380 mu atm). Our results also indicated that Prydz Bay has become a stronger sink of atmospheric CO2 in summer of 2015 (average flux of -21.4 +/- 27.3 mmol C m(-)(2) d(-1)) than that observed in summer of 2000 (average flux of -3.23 mmol C m(-)(2) d(-1)) as well as other reported fluxes in the continental shelf waters around the Antarctic.

为了研究海洋背景区域大气中多氯联苯(PCBs)的污染状况,于冬、春和夏季在福建省沿海岛屿东山岛连续采集大气颗粒物样品.结果显示,东山岛大气颗粒物中PCBs浓度范围为0.11-16.95 pg·m-3,平均值5.53±4.31 pg·m-3.通过对比其他区域发现,东山岛大气颗粒物中PCBs处于较低水平,其含量与海洋背景区域相当.PCBs浓度季节变化明显,表现为冬春季高而夏季低.冬季,PCBs以高氯取代化合物为主,而春、夏季以低氯取代化合物为主.气团来源的季节性变化、气象条件参数(如降雨量、温度、大气压、风速、相对湿度、水气压)是影响PCBs浓度变化的主要因素.东山岛大气颗粒物中PCBs的干沉降通量为1.34 ng· m-2· d-1,冬春季沉降通量明显高于夏季,按照东山岛海域覆盖面积(36200 km2)估算,每年PCBs以干沉降入海通量约为12.84 kg.

海洋大气化学是一门海洋化学与大气化学交叉的新学科.中国的南大洋海洋大气化学研究与我国的南极考察事业同步成长.30多年来,随着南极科学考察的经验积累和数据集成,我国的南大洋海洋大气化学关键过程研究即大气-海洋生物地球化学循环,碳、氮、硫、磷、铁等的海气交换研究都有了长足的进步.与气候变化关系密切的碳、氮、硫的海-气循环等研究,取得了一批新的认知和成果,引起国际学界的关注.自20世纪80年代早期开始至今,我国已开展了三十多次南极科学考察,在这些考察中开展了南大洋大气气溶胶物质来源研究,探究了大气-海洋生物地球化学的一些关键过程,估算了硫、磷、氮、铁的海气交换通量.随着国家重大计划"南极在全球变化中的响应与反馈作用"项目实施及后续研究的开展,对全球变化的敏感要素碳、氮、硫、铁在南大洋的源汇特征及其环境和气候效应等进行了研究,对其有了更深的了解.我们还对南大洋海冰区碳汇格局演变,DMS、MSA、N2O、Fe等的海气交换过程及其对生态环境的影响有了新认知.同时,在对上述化学物种的实时走航观测关键技术研发上也取得了重要突破,为未来开展相关研究提供了坚实的技术支持;在站区大气污染特征分布上进行了深入探讨,为了解人类活动对站区环境的影响提供了评估依据.

A comprehensive investigation using the air quality network and meteorological data of China in 2015 showed that PM 2.5 driven by cold surges from the ground level could travel up to 2000 km from northern to southern China within two days. Air pollution is more severe and prominent during the winter in north China due to seasonal variations in energy usage, trade wind movements, and industrial emissions. In February 2015, two cold surges traveling from north China caused a temporary increase in the concentration of PM 2.5 in Shanghai. Subsequently, the concentration of PM 2.5 in Xiamen increased to a high of 80 µg/m 3 , which is double the average PM 2.5 concentration in Xiamen during the winter. This finding is a new long-range transport mechanism comparing to the well-established mechanism, with long-range transport more likely to occur in the upper troposphere than at lower levels. These observations were validated by results from the back trajectory analysis and the RAMS- CMAQ model. While wind speed was found to be a major facilitator in transporting PM 2.5 from Beijing to Xiamen, more investigation is required to understand the complex relationship between wind speed and PM 2.5 and how it moderates air quality in Beijing, Shanghai, and Xiamen.

Aerosol samples were collected in the northwest Pacific and the eastern China coastal area in September 2015.We analyzed the concentrations of Na+,K+,Ca2+,Mg2+,Cl-,NH4+,NO3-,SO2-4 and dimethylsulfide (MSA)and explored 9 sources of water-soluble ions statistically.Significant difference in aerosol composition indi-cated that various airflow influence over 2 sea areas.Sea salt was the important original aerosol over the northwest Pacific and the terrestrial air with heavy crustal particles and anthropogenic aerosol affected the eastern China coast-al area.The concentration of K+,Ca2+,MSA and secondary ions were higher in the eastern China coastal area than in the northwest Pacific.The monthly atmospheric aerosol dry deposition fluxes of NH4+,NO3-,SO2-4 to the eastern China coastal area were obviously higher than the northwest Pacific in autumn by estimation.The input of nutrients has contributions increasing marine primary production and promoting the release of biological aerosol.

Selected trace elements, ionic species and organic/elemental carbon in aerosols were measured in summer at Ny–Alesund in the Arctic, and an interpreted approach combining elemental ratios, back–trajectories and enrichment factors was used to assess the sources of aerosols observed at this location. Aerosol samples influenced by ship emissions were featured by elevated concentrations of non–crustal (nc) vanadium (V), nc–nickel (nc–Ni), non–sea salt (nss) sulfate (SO42−) and ratios of nc–Ni/nc–V (1.7) and nss–SO42−/nc–V (200). When two cruise ships with more than 1 500 passengers visited Ny–Alesund in July 2012, the total suspended particulate (TSP) mass reached 2 290ng m−3, almost three times the median TSP concentration (609ng m−3) measured during the study period. The nc–V concentration reached 0.976ng m−3, about 38–fold higher compared to the mean value of the sampling period, and this value was even higher than the annual mean value observed at Zeppelin station and the values measured during Haze events at North American Arctic and Norwegian Arctic. The concentrations of nc–Ni and nss–SO42− were 0.572ng m−3 and 203ng m−3, which were 8–fold and 2–fold higher than the median values of the sampling period. While in the few–ship period, defined as the period with none or only one cruise ship with less than 1 000 passengers being present, aerosols at this location could be affected by a mixed impact of local emissions and long–range transport, reflected by the nc–Mn/nc–V ratios and element enrichment factors often found in the air masses from North America Arctic, Iceland and North Eurasia. Results from this study suggest that cruise ship emissions contributed significantly to atmospheric particulate matter at Ny–Alesund in the summer, effecting air quality in this area.