Sea Level Research Articles

Analysis of Spatial and Temporal Trends of Vegetation Cover Evolution and Its Driving Forces from 2000 to 2020—A Case Study of the WuShen Counties in the Maowusu Sandland

The WuShen counties in the hinterland of the Maowusu Sandland are located in the “ecological stress zone” of the forest–steppe desert, with low vegetation cover, a strong ecosystem sensitivity, and poor stability under the influence of human activities. Therefore, it is important to study and analyze the changes in vegetation growth in this region for the purpose of objectively evaluating the effectiveness of desertification control in China’s agricultural and pastoral intertwined zones, and formulating corresponding measures in a timely manner. In this paper, the spatial and temporal variations in the vegetation NDVI in the WuShen counties of the Maowusu Sandland and their response relationships with driving factors were investigated by using a trend test, center of gravity transfer model, partial correlation calculation, and residual analysis, and by using the MOD13A3 vegetation NDVI time series data from 2000 to 2020, as well as the precipitation, temperature, and potential evapotranspiration data from the same period. The results showed the following: ① The regional vegetation NDVI did not fluctuate significantly with latitude and longitude, and the NDVI varied between 0.227 and 0.375 over the 21-year period, with a mean increase of 0.13 for the region as a whole and an increase of 0.61 for the region of greatest change. Of the area, 86.83% experienced a highly significant increase, and the trend in increase around rivers and towns was higher than that in the northwestern inland flow area, with the overall performance of “low in the west and high in the east”. ② Only 2.07% of the vegetation NDVI center of gravity did not shift, and the response with climate factors was mainly characterized by having consistent or opposite center of gravity changes with precipitation and potential evapotranspiration. ③ Human activities have been the dominant factor in the vegetation NDVI change, with 75.89 percent of the area positively impacted by human activities, and human activities in the southwest inhibiting the improvement of vegetation in the area. The impact of human activities on the unchanged land type area is increasing, most obviously in the farmland area, and the impact of human activities on the changed land type area is gradually decreasing in the area where the farmland becomes impervious. The vegetation in the area above 1300 m above sea level is degraded by the environment and human activities. The research results can provide scientific support for the implementation of ecological fine management and the formulation of corresponding ecological restoration and desertification control measures in the Maowusu Sandland. At the same time, it is expected to serve as a baseline for other studies on the evolution of vegetation in agro-pastoral zones.

SPECIFICITY OF FOUNDATION OF SOLAR PANELS

Considering that the expansion of the construction of solar power plants in the world, Bosnia and Herzegovina tends to follow the global trend in the construction of solar power plants, that is, to provide as much electricity as possible from renewable sources. One of the solar power plants in the Tuzla Canton was built by the company Deling doo at the location of Bosanska poljana. The terrain represents an alluvial plain, a flat part of the relief that was created by the work and accumulation action of the Jala river. The morphological conditions of the locality in question are relatively favorable due to the plain character of the vast alluvial plain, the average altitude of about 190.00 m above sea level. The foundation of the solar panels requires a bearing capacity for uprooting from the wind, that is, the load on the ground can be variable in the vertical direction, in extreme situations the uprooting force from the wind is significantly greater than the gravitational force of the solar panels. Considering that it is a terrain where the effect of the Jala river is very pronounced, it was necessary to propose an adequate way of foundation of the solar panels in order to meet the stated conditions. The paper shows the way in which the depth of the panel foundation was determined, that is, the experimental determination of the depth of the load-bearing soil.

Extending the blended generalized extreme value distribution

AbstractThe generalized extreme value (GEV) distribution is commonly employed to help estimate the likelihood of extreme events in many geophysical and other application areas. The recently proposed blended generalized extreme value (bGEV) distribution modifies the GEV with positive shape parameter to avoid a hard lower bound that complicates fitting and inference. Here, the bGEV is extended to the GEV with negative shape parameter, avoiding a hard upper bound that is unrealistic in many applications. This extended bGEV is shown to improve on the GEV for forecasting heat and sea level extremes based on past data. Software implementing this bGEV and applying it to the example temperature and sea level data is provided.

Contrasting Rainfall Anomaly Patterns Over South America Related to Central and Eastern Atlantic Niño Modes

ABSTRACTThe present study examines the effects of the central Atlantic Niño (CAN) and eastern Atlantic Niño (EAN) events on the seasonal precipitation in South America (SA) during the 1951–2020 period. For the CAN during the summer and autumn, an interhemispheric sea surface temperature (SST) dipole mode induces an anomalous thermally direct circulation in the 10° N–10° S band and is the main factor causing precipitation anomaly patterns with a dipole structure between northern (negative) and northeastern (positive) SA. For winter and spring, the SST pattern featuring a South Atlantic dipole induces meridional and zonal anomalous circulations, which are the mechanisms causing positive precipitation anomalies in tropical SA to the north of 20° S. In contrast, for the EAN, the precipitation anomaly patterns show large areas with anomalous dryness, particularly during summer, autumn, and spring. For summer and autumn, the east–west SST anomaly gradient in the equatorial Atlantic and the associated sea level pressure (SLP) anomalies induce equatorial westerlies and a regional Walker cell with descending motions in most tropical SA, where large areas with anomalous dryness are noted. During spring, a northward SST gradient in the tropical Atlantic induces a meridional cell with descending motions in the 0°–10° S band; meanwhile, the westward SST gradient in the equatorial Atlantic and tropical South Atlantic induces a zonal circulation with descending motions over northeastern and eastern Brazil. These descending motions extend the anomalous dryness over a large area. For the EAN events, the east–west SST gradient and the associated east–west circulation in the South American/Atlantic region are crucial elements to modulate precipitation variability in SA. Therefore, the CAN and EAN events induce distinct precipitation anomaly patterns in SA due to distinct associated regional circulation patterns. The results presented here have not been discussed before and might have relevant implications for climate monitoring and modelling studies.

Analysis and forecast of sea level change in the China Seas and neighboring oceans from 1993 to 2020

Analysis and forecast of sea level change in the China Seas and neighboring oceans from 1993 to 2020

On the skill of Indo-Pacific decadal sea level predictions and its connection with skilful AMO and PDO predictions

On the skill of Indo-Pacific decadal sea level predictions and its connection with skilful AMO and PDO predictions

Pushing Scuba to New Heights: Approach, Decompression, and Logistical Considerations for High-Altitude Diving.

There is interest among technical, expedition, commercial, and military divers in expanding diving operations to high altitude. However, altitude diving presents unique challenges including acclimatization, increased decompression sickness (DCS) risk, and logistical and equipment considerations. Divers must plan altitude acclimatization strategies conservatively to reduce risk of acute mountain sickness and dehydration before diving. Several methods of augmenting sea level diving tables to be used at altitude have been theorized and tested both in simulated dives and high-altitude expeditions. With proper acclimatization, augmentation of standard diving tables, equipment, and safety planning, diving at high altitude may be performed in many contexts safely while minimizing risk of DCS or injury.

Substantial reduction in population exposure to sea level changes along the Chinese mainland coast through emission mitigation

Abstract Rising sea level increases the exposure to flooding and related damage in coastal areas with high population density and substantial economic activity. As global temperatures continue to rise due to climate change, sea levels have been consistently increasing and are projected to continue this upward trend. This study assesses the future exposure at provincial and city levels populations coastal mainland China coast to local sea level changes under five greenhouse gas (GHG) emission scenarios from IPCC-AR6, as well as two low-confidence scenarios accounting for the potential impact of uncertain ice sheet processes with low- and high-GHG emissions. We incorporate spatial heterogeneity into regional sea level projections and population projections from 2020 to 2100, extreme sea levels (ESLs) of 10-, 50-, and 100 year return periods (RP), and local coastal protection standards. Our findings indicate that the inundated areas expand continuously within the century with heightened exposure under higher emission scenarios. Although the coastal population is projected to decline, the fraction of the coastal population exposed to flooding increases across all scenarios, with accelerated growth under higher GHG emissions and higher ESLs. Zhejiang and Jiangsu emerge as the provinces most exposed to sea-level rise, whereas Taizhou, Nantong, Wuxi, Panjin, and Huzhou are identified as the top five cities with the highest population exposure to local sea level rise (SLR). Transitioning towards a sustainable scenario (i.e. SSP1-2.6) rather than a fossil fuel-intensive one (i.e. SSP5-8.5) can reduce the local SLR and substantially mitigate these exposures. Compared to the median projections under SSP5-8.5, aligning GHG emissions with SSP1-2.6 could reduce population exposure substantially in all coastal provinces, especially in Jiangsu, where population exposure to 100 year RP coastal floods would be reduced by ∼1.6 M in 2050 and by ∼5.4 M in 2100.

Salinity challenges and adaptive strategies in salinization-affected coastal Bangladesh: Implications for agricultural sustainability and water resource management

Abstract Salinization has become a rising global concern due to its notable effects on agriculture and freshwater resources. Coastal region of Bangladesh has been struggling with elevated levels of soil and water salinity, exacerbated by storm surges and rising sea levels. We assessed nutrient and salinity contents in agricultural and homestead lands, and the level of salinity in pond and canal water in six sub-districts in coastal Bangladesh. Finally, using household (HH) survey, focus group discussion (FGD) and key informant interview (KII), we explored the adaptive practices and challenges of salinity issues in agriculture and drinking water management. Soil nitrogen, phosphorus, and potassium contents exhibited significant variations across the sub-districts, which reflect the diversity of agricultural practices and soil management strategies. However, there was no notable difference in soil salinity across the sub-districts, which underscores the commonality of soil salinity as a pressing concern. Shyamnagar (13.99 dS m−1) recorded the highest level of pond water salinity, followed by Assasuni (13.96 dS m−1), Dacope (13.91 dS m−1), Koyra (13.58 dS m−1), Morrelganj (13.33 dS m−1), and Mongla (13.19 dS m−1) sub-districts, which highlights that water salinity decreased from exposed coast to the landward areas. Respondents in HH surveys, FGDs and KIIs identified salinity as a major challenge in agriculture and drinking water. Furthermore, climate-related stresses were recognized as significant challenges impacting crop productivity. The research highlights the feasibility of rainwater harvesting, with 89%–100% of HHs harvest rainwater in HH tanks, as an effective adaptive practice for managing drinking water. The study emphasizes the positive impact of vermicompost in reducing soil salinity levels, which is demonstrated by the 43%–88% of HHs using this practice, indicating its potential as a nature-based solution to address soil salinization. The findings underscore the need for resilient agricultural systems and sustainable water management approaches to tackle these challenges.

Applying portfolio theory to benefit endangered amphibians in coastal wetlands threatened by climate change, high uncertainty, and significant investment risk

The challenge of selecting strategies to adapt to climate change is complicated by the presence of irreducible uncertainties regarding future conditions. Decisions regarding long-term investments in conservation actions contain significant risk of failure due to these inherent uncertainties. To address this challenge, decision makers need an arsenal of sophisticated but practical tools to help guide spatial conservation strategies. Theory asserts that managing risks can be achieved by diversifying an investment portfolio to include assets – such as stocks and bonds – that respond inversely to one another under a given set of conditions. We demonstrate an approach for formalizing the diversification of conservation assets (land parcels) and actions (restoration, species reintroductions) by using correlation structure to quantify the degree of risk for any proposed management investment. We illustrate a framework for identifying future habitat refugia by integrating species distribution modeling, scenarios of climate change and sea level rise, and impacts to critical habitat. Using the plains coqui (Eleutherodactylus juanariveroi), an endangered amphibian known from only three small wetland populations on Puerto Rico’s coastal plains, we evaluate the distribution of potential refugia under two model parameterizations and four future sea-level rise scenarios. We then apply portfolio theory using two distinct objective functions and eight budget levels to inform investment strategies for mitigating risk and increasing species persistence probability. Models project scenario-specific declines in coastal freshwater wetlands from 2% to nearly 30% and concurrent expansions of transitional marsh and estuarine open water. Conditional on the scenario, island-wide species distribution is predicted to contract by 25% to 90%. Optimal portfolios under the first objective function – benefit maximization – emphasizes translocating frogs to existing protected areas rather than investing in the protection of new habitat. Alternatively, optimal strategies using the second objective function – a risk-benefit tradeoff framework – include significant investment to protect parcels for the purpose of reintroduction or establishing new populations. These findings suggest that leveraging existing protected areas for species persistence, while less costly, may contain excessive risk and could result in diminished conservation benefits. Although our modeling includes numerous assumptions and simplifications, we believe this framework provides useful inference for exploring resource dynamics and developing robust adaptation strategies using an approach that is generalizable to other conservation problems which are spatial or portfolio in nature and subject to unresolvable uncertainty.

Study of cosmic rays with energies above 5 EeV using radio method

At the Yakutsk array in 1986 regular measurements of radio emission produced by relativistic air shower particles were started. After monitoring of background noise in the array area frequency of 30–35 MHz was chosen, since noise level is minimal in this frequency range. During this time, air showers with highest energies of 100 EeV were registered. By using hybrid measurements of charged particles, Cherenkov light and radio emission it was shown that signal amplitude proportional to air shower energy and shape of lateral distribution at sea level correlates with the depth of maximum development. Using the obtained characteristics, atomic weight of primary particles that generated air shower was estimated within QGSjetII-04 framework simulation.

Floods in the Pyrenees: a global view through a regional database

Abstract. This paper shows the first systematic dataset of flood episodes referring to the entire Pyrenees massif, named PIRAGUA_flood, which covers the period 1981–2015 (available at http://hdl.handle.net/10261/270351, last access: 21 July 2024). First, the structure of the database is detailed so that it can be reproduced anywhere else in the world, adapting to the specific nature of each situation. Subsequently, the paper addresses the spatial and temporal distribution of flood episodes and events (including trends) that affected the Pyrenees regions of Spain (Catalonia, Aragon, Navarre, the Basque Country), France (Nouvelle-Aquitaine, Occitanie) and Andorra, as well as the massif as a whole, for a given period of time. In the case of the Spanish regions, it was also possible to analyse the compensation payments by the Spanish Insurance Compensation Consortium and the number of deceased. The weather types associated with flood episodes were also classified based on sea level pressure and 500 hPa geopotential height from ERA5. The results show 181 flood events and 154 fatalities, some of which affected more than one region. In the Spanish part of the Pyrenees, between 1996 and 2015, there was a total compensation payout amounting to EUR 142.5 million (2015). The eastern part of the area records more flood events than the western one, with Catalonia being the community that registered the highest number of events, followed by Andorra and Occitanie. Associated weather types are dominated by the southern component flow over the Pyrenees region, with a talweg on the Iberian Peninsula and a depression in the vicinity, either in the Atlantic or in the Mediterranean. In terms of the entire massif, there is a slight positive trend of 0.84 events per decade, driven by the evolution of ordinary and extraordinary floods but not significant at 95 %. At a regional level, flood behaviour is more heterogeneous, although not significant for the most part. Nouvelle-Aquitaine is the only region that shows a positive and significant trend of 0.34 events per decade.

Spatial inhomogeneity analyses of extreme sea levels along Lianyungang coast based on numerical simulation and Monte Carlo model

The prediction of extreme sea levels in coastal areas has been a prominent requirement of coastal engineering design and planning. The research was based on the frequent disasters caused by typhoon storm surges in China and the demand for reasonable improvement of port structures in coastal areas. Delft3D hydrodynamic model and the Monte Carlo model were integrated to predict the spatial distribution of extreme sea levels along the coast of Lianyungang city in Jiangsu province. The Monte Carlo model was adopted to generate stochastic typhoon characteristic sequences as meteorological driving forces. In the hydrodynamic model, meteorological factors were coupled with the astronomical tide to simulate storm surge scenarios. Extreme sea levels were estimated by ranking maximum levels of simulated storm surge events. This programming was feasible compared to the prediction results of frequency analysis methods. The research showed that the predicted 1 in 100-year extreme sea level of Lianyungang station was 3.75 m, while the predicted 1 in 200-year value was 3.85 m. The programming was adopted to predict extreme sea levels of several stations and analyze the spatial distribution characteristics of extreme sea levels in four port areas of Lianyungang Port. Results revealed that extreme sea levels in modeling areas had significant spatial inhomogeneity, which might be related to the concavity of coastlines, islands, and terrains. Estimating spatial extreme sea levels could better cognize the influence of inundation disasters in coastal areas and be conducive to the design of port structures and the safety of port operations.

Variability of UCP1 and UCP3 uncoupling protein genes in relation to climate in indigenous populations of Siberia and the Far East

Introduction. Several studies have demonstrated a correlation between variations in genes regulating human uncoupling proteins (UCP) and environmental factors. However, information on the intra- and interpopulation diversity of allele and genotype frequencies of UCP1 and UCP3 within the territory of Russia remains insufficient. This study aims to investigate the intra- and inter-ethnic variability of genetic determinants of activity of uncoupling proteins UCP1 and UCP3, and to evaluate genotype-environment associations in the populations residing in the northeastern region of Russia. Materials and methods. Genotyping was conducted on a total of 1,698 biological specimens collected from individuals representing 22 population groups of European Russia, Siberia, and the Russian Far East. Geographical and climatic data spanning from 1940 to 2023 were gathered for each sample collection locality. Results and discussion. The spatial distribution of genetic determinants affecting the activity of UCP1 and UCP3 uncoupling proteins demonstrates a correlation with the severity of natural conditions. Three regression models of allele frequencies were constructed using climatic characteristics as predictors. All models are statistically significant (p<0.05 in all cases) and explain 39%, 36%, and 64% of the variability in UCP1 (rs6536991, rs1800592) and UCP3 (rs1800849) allele frequencies, respectively. These correlations revealed by the models confirm the adaptability of UCP genes in the indigenous population groups of Northern Eurasia. Conclusion. The results of this study are consistent with the assumptions reported in scientific literature and significantly enhance existing knowledge. We observed correlations between allele and genotype frequencies of UCP1 (rs6536991, rs1800592) and UCP3 (rs1800849) genes and geographic latitude, elevation above sea level, as well as climatic indicators such as annual average rainfall, range of surface air temperatures, and the Bodman “weather severity” index. Further investigation involving a larger number of ethnic and territorial groups is necessary to better understand the factors influencing UCP gene variability formation.

Holocene benthic foraminifera ecological succession in the Panamanian Caribbean

Benthic foraminifera assemblages from a 452 cm long sediment core (GAL18) were collected from a mangrove forest on the Caribbean coast of Panama. The core spans the last ∼5200 cal yrs. B.P. Ninety-six benthic species were recorded in the sedimentary sequence. The most frequent and abundant were the calcite hyaline species Ammonia batava, Ammonia tepida, Ammonia ariakensis, Elphidium articulatum, Elphidium cristobalense, and Cribroelphidium galeroense. The second most abundant were four porcelaneous species: Quinqueloculina cf. araucana, Quinqueloculina cf. poeyana, Quinqueloculina neocostata and Quinqueloculina seminulum. There were also scattered species of agglutinant taxa along the core and in modern sediments. Micropaleontological, sedimentological, and geochemical analyses allowed the recognition of four lithologic units that were consistent with four paleoenvironmental scenarios of ecological succession. (I) The Estuarine Zone deposited at ∼5200–3600 cal yrs. B.P. suggests the development of a mangrove ecosystem along a channeled tidal area with estuarine water exchange and dominant species from brackish waters such as Ammonia and Cribroelphidium. Isotopic (δ13Corg, δ15N), geochemical (C/N, Ca/Ti, K/Rd, Fe/Ca), and pollen data also show a polyhaline environment with bio-calcite production and active coastal weathering. (II) The Seaward Zone deposited between ∼3600–1250 cal yrs. B.P., closest to marine waters, with an overall increase in benthic species, like the euhaline Quinqueloculina spp., and other calcareous organisms. (III) The Transition Zone was deposited amid 1250–650 cal yrs. B.P. when the area experienced less frequent flooding by tidal waters, dominated by polyhaline Elphidium and Ammonia spp., and the establishment of a mangrove ecosystem influenced by changing salinity, as the sea level almost reached its modern position. Finally, (IV) the Landward Zone deposited over the last 650 cal yrs. B.P., where the lack of benthic foraminifera and bio-calcite deposits contrast with high amounts of organic carbon and vegetal debris, which supports that the core site was located further inland than in previous intervals. This multiproxy study features subtle but irreversible changes that a fringe mangrove community can experience over time, highlighting the complex relationship between the coastal region and the sea.

Late Pleistocene to early Holocene vegetation and environmental changes in the tropical Leizhou Peninsula, South China: New evidence from the n-alkane record

Understanding past long-term vegetation responses to regional or even global climate change and forcing mechanisms is essential to future climate change projections. However, due to the lack of long-term terrestrial sedimentary records, there are few studies focusing on vegetation changes in tropical southern China since the last glacial period, especially from the perspective of peat n-alkane records. Here, we have presented a peat core record from the Xialu peatland in the northern Leizhou Peninsula, and n-alkanes were investigated in conjunction with multiple proxy indicators. Our results showed that the organic matter sources were mainly a mixture of aquatic and terrestrial vegetation, with terrestrial vegetation accounting for most of the bulk organic matter composition. From ∼44.1 to 29 cal kyr BP, the organic matter source was mainly dominated by terrestrial vegetation, which corresponds to warm and humid conditions. From 29 to 14 cal kyr BP, the input of the terrestrial vegetation was reduced, the aquatic vegetation input increased, implying cool and dry conditions. From 14 to 9.3 cal kyr BP, the climate gradually became warmer and wetter, and terrestrial vegetation dominated in this area. Overall, the climatic conditions from the Xialu peatland were generally consistent with other records from adjacent areas. Our results suggest that, during the Last Glacial Maximum (LGM), a substantial drop in regional and global sea levels may have been the main cause of drought in tropical southern China on orbital timescales. Meanwhile, several climatic fluctuations on millennial timescales could have been influenced by the variability of the North Atlantic Meridional Overturning Circulation (AMOC) and migration of the Intertropical Convergence Zone (ITCZ).

Microbial mediated hardening of a Central Mediterranean upper shelf seafloor during the MIS 5.5; a possible post global warming scenario?

Higher sea level and sea surface temperature than at present have been inferred for the Last Interglacial (MIS 5.5, 135–116 ka), making it a good analogue for modeling the climate response of the environment to global warming in the near future. With the aim of predicting the possible evolution of some central Mediterranean shallow sandy seabeds, a MIS 5.5 biocalcarenite was investigated (Gulf of Taranto, Italy). Limited post-depositional diagenesis affected this deposit, which represents an infralittoral sandy seabed, with local vegetation and relatively high energy conditions. Medium-coarse sand sized bioclasts, with a negligible quantity of siliciclastic, compose the sediment that also hosts large shells of mollusks. Micritic cements are widespread, often in continuum with the micritized part of the shells, showing non-isopachous aphanitic and filamentous rims, aphanitic micro-mounds, vacuolar peloidal menisci, and aphanitic pore-filling matrix. All these cements consist of submicrometer anhedral or nanospheroidal crystals of low-Mg calcite, mixed with a smaller amount of irregular plate-like crystals of saponite. Micritic cements are also rich in mineralized filamentous, tubular, and subspherical bacterial bodies. This highlights the occurrence of an epilithic and endolithic microbial community forming a biofilm that stabilized the mobile sediment as consequence of the microbial mediated early cement precipitation. This led the synsedimentary hardening of some parts the mobile sandy substrate, the settlement of sessile taxa - such as Spondylus gaederopus, oysters, serpulids and barnacles, together with endofaunal organisms. Early micritic cementation is common in modern tropical climate, whereas is substantially absent in the modern Mediterranean. Consequently, its presence in the MIS 5.5 deposit confirms warmer sea water temperature compared to today (estimated at ca +2 °C) and suggests that similar hardening of mobile substrates may occur in the near future as a response to global warming.

Sodium Hydrosulfide Protects Rats from Hypobaric-Hypoxia-Induced Acute Lung Injury

Hydrogen sulfide (H2S), as a key gas signaling molecule, plays an important role in regulating various diseases, with appropriate concentrations providing antioxidative, anti-inflammatory, and anti-apoptotic effects. The specific role of H2S in acute hypoxic injury remains to be clarified. This study focuses on the H2S donor sodium hydrosulfide (NaHS) and explores its protective effects and mechanisms against acute hypoxic lung injury. First, various mouse hypoxia models were established to evaluate H2S’s protection in hypoxia tolerance. Next, a rat model of acute lung injury (ALI) induced by hypoxia at 6500 m above sea level for 72 h was created to assess H2S’s protective effects and mechanisms. Evaluation metrics included blood gas analysis, blood routine indicators, lung water content, and lung tissue pathology. Additionally, LC-MS/MS and bioinformatic analyses were combined in performing quantitative proteomics on lung tissues from the normoxic control group, the hypoxia model group, and the hypoxia model group with NaHS treatment to preliminarily explore the protective mechanisms of H2S. Further, enzyme-linked immunosorbent assays (ELISA) were used to measure oxidative stress markers and inflammatory factors in rat lung tissues. Lastly, Western blot analysis was performed to detect Nrf2, HO-1, P-NF-κB, NF-κB, HIF-1α, Bcl-2, and Bax proteins in lung tissues. Results showed that H2S exhibited significant anti-hypoxic effects in various hypoxia models, effectively modulating blood gas and blood routine indicators in ALI rats, reducing pulmonary edema, improving lung tissue pathology, and alleviating oxidative stress, inflammatory responses, and apoptosis levels.

Discerning sediment provenance in the Outer Banks (USA) through detrital zircon geochronology

Detrital zircon data from modern barrier island and estuarine environments in the Outer Banks (Atlantic Coast, USA) were statistically compared to sands from nearby rivers to assist in determining source-to-sink pathways. Fluvial samples, collected from near the Fall Line contact between the Appalachian Orogen and sediments of the coastal plain, all have age unique distributions, making them ideal for tracing provenance. Three samples from the Atlantic foreshore showed high similarities to one another, as well as to three samples from the estuarine (back-barrier) Pamlico and Albemarle Sounds. Mixture modeling with multiple data reduction methods and three different statistical tests for similarity consistently indicated that the nearby Potomac River was the primary source for all Atlantic foreshore and estuarine zircons, followed by minor contributions from the James River in some models. The models indicate little or no sediment contribution from the Susquehanna, Roanoke, Tar, Neuse, Cape Fear, and Peedee Rivers. Both Atlantic foreshore and estuarine sands are therefore interpreted to have initially originated from Appalachian bedrock to the north of their present-day location, and subsequently to have been transported southward through the Chesapeake Bay watershed before deposition in Virginia and North Carolina. Prior to barrier island formation in the last several thousand years, differing geomorphology of the Chesapeake Bay facilitated southward movement of sediments from its constituent rivers via longshore drift, where they were deposited in coastal settings on the mainland. The modern barrier islands, formed during the most recent post-glacial transgression, may be reworked from these deposits, but may also include a contribution from sediments that were derived more recently from relict deposits on the shelf. Oceanographic and sedimentological evidence suggests that movement of sand-sized grains from southern rivers across the back-barrier sounds is unlikely. These findings can assist with coastal resilience planning and resource management in a region under severe threat from climate change and rising sea levels.

Preliminary ESR dating results of fault barite shed new insights into the retrospective history of bedrock fault activities in basaltic regions

The chronology of fault activity in bedrock is critical to constraining and understanding periods of active faulting, assessing seismic hazards, and mitigating the effects of earthquakes. However, because of the lack of suitable materials for dating, the temporal reconstruction of faulting in bedrock remains highly challenging for geologists. In the present study, we determine for the first time the electron spin resonance (ESR) ages of fault barite (BaSO4), which is produced by episodes of intense faulting on basalt bedrock fault surfaces. Three barite samples were obtained from a basalt fault section (27°5′23″N, 100°25′45″E, 1.8 km above sea level) of the Lijiang–Xiaojinhe Fault (LXF), southeastern Tibetan Plateau, for ESR measurements. Similar to marine barite, the ESR spectrum of fault barite shows an electron-type center with g = 2.0037, 2.0034, and 2.0028 attributed to SO3−. The signal intensity systematically increased with increasing gamma-ray dose. Dose rates were calculated using a model based on the location and burial depth of the barite samples, as well as their surrounding bedrock. The three barite samples yield ESR ages of 131 ± 26, 503 ± 61, and 1416 ± 246 ka, respectively, which indicate that the LXF was active during the Early and Middle Pleistocene. The three ESR ages for fault barite from basalt extend the time range of activity of the LXF compared with previous carbonate ESR and radiocarbon dating results. Consequently, we propose that ESR dating of barite is valuable for reconstructing the history of bedrock fault activity. However, given that this investigation represents a preliminary application of the fault-barite ESR method, further study is needed to confirm its usefulness and the accuracy and precision of dating results.