Modeling geologically abrupt climate changes in the Miocene: Potential effects of high-latitudinal salinity changes

The cooling of the Cenozoic, including the Miocene epoch, was punctuated by many geologically abrupt warming and cooling episodes— strong deviations from the cooling trend with time span of ten to hundred thousands of years. Our working hypothesis is that some of those warming episodes at least partially might have been caused by dynamics of the Antarctic Ice Sheet, which, in turn, might have caused strong changes of sea surface salinity in the Miocene Southern Ocean. Feasibility of this hypothesis is explored in a series of offline-coupled ocean-atmosphere computer experiments. The results suggest that relatively small and geologically short-lived changes in freshwater balance in the Southern Ocean could have significantly contributed to at least two prominent warming episodes in the Miocene. Importantly, the scenario-based experiments also suggest that the Southern Ocean was more sensitive to the salinity changes in the Miocene than today, which can attributed to the opening of the Central American Isthmus as a major difference between the Miocene and the present-day ocean-sea geometry.

Spatio-Temporal Changes of Soil Salinity in Arid Areas of South Xinjiang Using Electromagnetic Induction

The aim of this paper was to research the spatio-temporal changes in total soluble salt content （TS） in a typical arid region of South Xinjiang, China, where the climate is arid and soil salinization happens easily. The total soluble salt content was interpreted by measurements made in the horizontal mode with EM38 and EM31. The electromagnetic induction （EM） surveys were made three times with the apparent soil electrical conductivity （ECa） measurements taken at 3 873 locations in Nov. 2008, 4 807 locations in Apr. 2009 and 6 324 locations in Nov. 2009, respectively. For interpreting the ECa measurements into total soluble salt content, calibtion sites were needed for EM survey of each time, e.g., 66 sites were selected in Nov. 2008 to measure ECa, and soils-core samples were taken by different depth layers of 0-10, 10-20 and 20-40 cm at the same time. On every time duplicate samples were taken at five sites to allevaite the local-scale variability, and soil temperatures in different layers through the profiles were also measured. Factors including TS, pH, water content, bulk density were analyzed by lab experiments. ECa calibration equations were obtained by linear regression analysis, which indicated that soil salinity was one primary concern to ECa with a determination coefficient of 0.792 in 0-10 cm layer, 0.711 in 10-20 cm layer and 0.544 in 20-40 cm layer, respectively. The maps of spatial distribution were predicted by Kriging interpolation, which showed that the high soil salinity was located near the drainage canal, which validated the trend effect caused by the irrigation canal and the drainage canal. And by comparing the soil salinity in different layers, the soluble salt accumulated to the top soil surface only in the area where the soil salinization was serious, and in the other areas, the soil salinity trended to increase from the top soil surface to 40 cm depth. Temporal changes showed that the soil salinity in November was higher than that in April, and the soil salinization trended to aggravate, especially in the top soil layer of 0-10 cm.

Comparative transcriptome analysis on the alteration of gene expression in ayu （Plecoglossus altivelis）larvae associated with salinity change

Ayu （Plecoglossus altivelis） fish, which are an amphidromous species distributed in East Asia, live in brackish water （BW） during their larval stage and in fresh water （FW） during their adult stage. In this study, we found that FW-acclimated ayu larvae exhibited a slower growth ratio compared with that of BW-acclimated larvae. However, the mechanism underlying FW acclimation on growth suppression is poorly known. We employed transcriptome analysis to investigate the differential gene expression of FW acclimation by RNA sequencing. We identified 158 upregulated and 139 downregulated transcripts in FW-acclimated ayu larvae compared with that in BW-acclimated larvae. As determined by Gene Ontology annotation and Kyoto Encyclopedia of Genes and Genomes pathway mapping, functional annotation of the genes covered diverse biological functions and processes, and included neuroendo- crinology, osmotic regulation, energy metabolism, and the cytoskeleton. Transcriptional expression of several differentially expressed genes in response to FW acclimation was further confirmed by real-time quantitative PCR. In accordance with transcriptome analysis, iodothyronine deiodinase （ID）, pro-opiom- elanocortin （POMC）, betaine-homocysteine S-meth- yltransferase 1 （BHMT）, fructose-bisphosphate aldolase B （aldolase B）, tyrosine aminotransferase （TAT）, and Na＋-K＋ ATPase （NKA） were upregulated after FW acclimation. Furthermore, the mRNA expressions of b-type natriurefic peptide （BNP） and transgelin were downregulated after FW acclimation. Our data indicate that FW acclimation reduced the growth rate of ayu larvae, which might result from the expression alteration of genes related to endocrine hormones, energy metabolism, and direct osmoregulation.

Relationship Between Diurnal Changes of Net Photosynthetic Rate and Influencing Factors in Rice under Saline Sodic Stress

The net photosynthetic rate of flag leaves and influencing factors under saline sodic soil conditions were investigated at the full heading stage of rice. The net photosynthetic rate of rice leaves showed a double-peak curve in a day in both non-saline sodic and saline sodic soil treatments. The first peak of the net photosynthetic rate appeared at 9：00-10：00 and 9：00 in the saline sodic and non-saline sodic soil treatments, respectively, whereas the second peak both at 14：00. The midday depression of the net photosynthetic rate always appeared regardless of non-saline sodic or saline sodic soil conditions. In addition, the net photosynthetic rate significantly decreased in all day under saline sodic conditions compared with that under non-saline sodic conditions. Some differences were observed in correlation characters between the net photosynthetic rate and all influencing factors during 9：00-13：00. Under non-saline sodic conditions, the diurnal changes of the net photosynthetic rate in a day were mainly caused by stomatal conductance, and the limitation value and the stomatal factors served as determinants; whereas under saline sodic stress, the diurnal changes of the net photosynthetic rate in a day were mainly caused by non stomatal factors including light intensity and air temperature.

Impacts of climate change on water quantity, water salinity, food security, and socioeconomy in Egypt

Climate change might have direct impacts on water quantity in Egypt and lead to indirect effects on Mediterranean saltwater intrusion to groundwater,which exposes agriculture to vulnerability.This study investigated impacts of climate change on agriculture,with particular regard to food security and socioeconomy,and quantified the effectiveness of cropping pattern adaptation measures by integrating three mathematical models.The BlueM model was used for hydrological simulations of Nasser Lake under flooding scenarios to predict the water supply from the High Aswan Dam.The water and salinity balance(WB-SAL)model was adopted to estimate the water salinity in the Nile Delta.The simulated results from the BlueM and WB-SAL models were integrated with the agricultural simulation model for Egypt(ASME)to project cropping patterns,food security,and socioeconomy throughout the country.The results showed that future climate change will directly affect the total crop area;crop areas for 13 crop types;the self-sufficiency of wheat,rice,cereal,and maize supplies;and socioeconomic indicators.The proposed cropping pattern adaptation measures focus on fixing the crop areas of rice and orchards and providing half of the population with lentils,maize,onion,vegetables,milk,and meat.The adaptation measures have the potential to promote food security without causing deterioration of the socioeconomic situation.However,water availability has much more significant effects on food security and socioeconomy than cropping pattern adaptation measures do.Accordingly,the country should rationalize water use efficiency and increase water supply.©2021 Hohai University.Production and hosting by Elsevier B.V.This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).

Quantitative Assessment of Impacts of Regional Climate and Human Activities on Saline-alkali Land Changes:A Case Study of Qian'an County,Jilin Province

Interdecadal and interannual variations of saline-alkali land area in Qian′an County, Jilin Province, China were comprehensively analyzed in this paper by means of satellite remote sensing interpretation, field flux observations and regional climate diagnosis.The results show that on the interannual scale, the impact of climate factors accounts for 71.6% of the total variation of the saline-alkali land area, and that of human activities accounts for 28.4%.Therefore the impact of climate factors is obviously greater than that of human activities.On the interdecadal scale, the impact of climate factors on the increase of the saline-alkali land area accounts for 43.2%, and that of human activities accounts for 56.8%.The impact of human activities on the variation of saline-alkali land area is very clear on the interdecadal scale, and the negative impact of human activities on the environment should not be negligible.Besides, changes in the area of heavy saline-alkali land have some indication for development of saline-alkali land in Qian′an County.

Climate and topography regulate the spatial pattern of soil salinization and its effects on shrub community structure in Northwest China

Soil salinization may affect biodiversity and species composition,leading to changes in the plant community structure.However,few studies have explored the spatial pattern of soil salinization and its effects on shrub community structure at the ecosystem scale.Therefore,we conducted a transect sampling of desert shrublands in Northwest China during the growing season(June–September)in 2021.Soil salinization(both the degree and type),shrub community structure(e.g.,shrub density and height),and biodiversity parameters(e.g.,Simpson diversity,Margalf abundance,Shannon-Wiener diversity,and Pielou evenness indices)were used to assess the effects of soil salinization on shrub community structure.The results showed that the primary degree of soil salinization in the study area was light salinization,with the area proportion of 69.8%.Whereas the main type of soil salinization was characterized as sulfate saline soil,also accounting for 69.8%of the total area.Notably,there was a significant reduction in the degree of soil salinization and a shift in the type of soil salinization from chloride saline soil to sulfate saline soil,with an increase in longitude.Regional mean annual precipitation(MAP),mean annual evapotranspiration(MAE),elevation,and slope significantly contributed to soil salinization and its geochemical differentiation.As soil salinization intensified,shrub community structure displayed increased diversity and evenness,as indicated by the increases in the Simpson diversity,Shannon-Wiener diversity,and Pielou evenness indices.Moreover,the succulent stems and leaves of Chenopodiaceae and Tamaricaceae exhibited clear advantages under these conditions.Furthermore,regional climate and topography,such as MAP,MAE,and elevation,had greater effects on the distribution of shrub plants than soil salinization.These results provide a reference for the origin and pattern of soil salinization in drylands and their effects on the community structure of halophyte shrub species.

Long-term Changes in the Saline Lake Qarun(Egypt)

1 Introduction There is now ample evidence of the impacts of the recent climate change and anthropogenic activities on different saline lake ecosystems.All over the world salt lakes are threatened by climate change,water diversions upstream for agricultural purposes,watershed changes,introduction of aliens,etc.that result in catastrophic

Impacts of the upper-ocean salinity variations on the decadal sea level change in the Southeast Indian Ocean during the Argo era

In the past nearly two decades,the Argo Program has created an unprecedented global observing array with continuous in situ salinity observations,providing opportunities to extend our knowledge on the variability and effects of ocean salinity.In this study,we utilize the Argo data during 2004–2017,together with the satellite observations and a newly released version of ECCO ocean reanalysis,to explore the decadal salinity variability in the Southeast Indian Ocean(SEIO)and its impacts on the regional sea level changes.Both the observations and ECCO reanalysis show that during the Argo era,sea level in the SEIO and the tropical western Pacific experienced a rapid rise in 2005–2013 and a subsequent decline in 2013–2017.Such a decadal phase reversal in sea level could be explained,to a large extent,by the steric sea level variability in the upper 300 m.Argo data further show that,in the SEIO,both the temperature and salinity changes have significant positive contributions to the decadal sea level variations.This is different from much of the Indo-Pacific region,where the halosteric component often has minor or negative contributions to the regional sea level pattern on decadal timescale.The salinity budget analyses based on the ECCO reanalysis indicate that the decadal salinity change in the upper 300 m of SEIO is mainly caused by the horizontal ocean advection.More detailed decomposition reveals that in the SEIO,there exists a strong meridional salinity front between the tropical low-salinity and subtropical high salinity waters.The meridional component of decadal circulation changes will induce strong cross-front salinity exchange and thus the significant regional salinity variations.

Seagull Lake,Western Eyre Peninsula,South Australia:A Saline Lake to Benefit from Climate Change? Ⅰ. Geomorphology,Invertebrates,Birds and the Future

Seagull Lake is an unusual saline lake,having a marine spring connected to a large continental ecosystem.With climate change the balance between the two is likely to change.This lake originated about 6000 years ago as a

Interaction between salinity intrusion and vegetation succession:A modeling approach

Predicting potential changes in groundwater salinity in low-lying coastal regions due to climate change is important, where coastal vegetation is abundant, succession competition between halophytes and glycophytes plays a significant role in the salinity budget. Sea level rise enhances salinity intrusion, contributing an additional dimension to vegetation competition. A new simulation model known as mangrove-hardwood hammock model coupled with saturated-unsaturated transport （MANTRA） has recently been developed by the authors to simulate groundwater salinity regimes in the presence of vegetation competition, subject to climate change. MANTRA is based upon linking two existing Unites States geological survey （USGS） simulation models known as mangrove-hardwood hammock model （MANHAM） and saturated-unsaturated transport （SUTRA）. MANHAM simulates the evolution of vegetation succession subject to changing groundwater salinity. SUTRA simulates saturated and unsaturated transport of solutes and salinity in groundwater given sea salinity. MANTRA improves the simulation robustness to simultaneously simulate groundwater hydrology, salinity and coastal vegetation succession subject to sea level rise. Some simulation results will be presented to demonstrate the impact of sea level rise on coastal vegetation succession and groundwater salinity.

Climate and salinity drive soil bacterial richness and diversity in sandy grasslands in China

Bacteria constitute a large proportion of the biodiversity in soils and control many important processes in terrestrial ecosystems.However,our understanding of the interactions between soil bacteria and environmental factors remains limited,especially in sensitive and fragile ecosystems.In this study,geographic patterns of bacterial diversity across four sandy grasslands along a 1,600 km north-south transect in northern China were characterized by high-throughput 16S rRNA gene sequencing.Then,we analyzed the driving factors behind the patterns in bacterial diversity.The results show that of the 21 phyla detected,the most abundant were Proteobacteria,Actinobacteria,Acidobacteria and Fir‐micutes(average relative abundance>5%).Soil bacterial operational taxonomic unit(OTU)numbers(richness)and Faith's phylogenetic diversity(diversity)were highest in the Otindag Sandy Land and lowest in the Mu Us Sandy Land.Soil electrical conductivity(EC)was the most influential factor driving bacterial richness and diversity.The bacterial communities differed significantly among the four sandy grasslands,and the bacterial community structure was signifi‐cantly affected by environmental factors and geographic distance.Of the environmental variables examined,climatic factors(mean annual temperature and precipitation)and edaphic properties(pH and EC)explained the highest propor‐tion of the variation in bacterial community structure.Biotic factors such as plant species richness and aboveground bio‐mass exhibited weak but significant associations with bacterial richness and diversity.Our findings revealed the impor‐tant role of climate and salinity factors in controlling bacterial richness and diversity;understanding these roles is critical for predicting the impacts of climate change and promoting sustainable management strategies for ecosystem services in these sandy lands.

Adaptation Strategy with Climate Induced Salinity Disaster in the Coastal Area of Bangladesh

This study examined explanatory responses to saline-water intrusion in the coastal areas of Bangladesh which are renowned for providing ecological and livelihood services. The goal of this study is to look at the different adaption strategies which coastal people have been using to deal with the growing salty water incursion. To this end, the researchers conducted a survey on 100 (one hundred) coastal people (Female 37% & Male 63%) chosen at a random basis from two unions (the lowest tier of local government) namely Perikhali union of Rampal upazila under Bagerhat district and Banishanta union of Dacope upazila under Khulna District at the southwest coast of Bangladesh. Agriculture (30%) and fisheries (27%) were the main livelihoods of the respondents. While looking at their existing problems due to salinity, it is seen that around 65% people are to move 3 - 5 (three to five) kilometres to get water access, low yield from agriculture (47%) and conversion of agricultural land (25%), acute crisis of grazing land (50%), damaged housing of cattle (30%) and fisheries (92%) are being affected due to salinity. Along with the impact, locals also have adaptation like seasonal water storage (31%), desalination (30%) and rainwater harvesting (26%) for water related impact. For agriculture, farmers are rotating crops (32%), cultivating saline tolerant varieties and others have switched from rice cultivation to other crops (30%) and cultivating saline tolerant variety (32%). In livestock, farmers are using better management practices (39%) followed by complete shift of livestock rearing (20%) to other businesses. Shifting from freshwater fish to marine water fish and crab/prawn cultivation (38%) found the most adaptation practices by the communities. For long term resilience to salinity induced disaster, collection of safe water (93%), quality seed (57%), disease control (47%) in livestock and quality hatchlings are the main barriers identified by the communities. For strengthening the current adaptation practices, rainwater harvesting (41%), household filtering of water (34%), ensuring of quality seeds (67%) and interest free loan to women through local NGOs have been stressed by the communities, local government officials as well as civil societies. Changes in land use patterns, use of contemporary technologies in agriculture, crop diversification, growing saline tolerant crops, income sources diversification, cultivating of saline tolerant fishes, utilization of savings, and rainwater harvesting are all prevalent adaptation strategies in the studied area. Moreover, to effectively address salinity in the coastal area of Bangladesh, the study also recommends increasing budget allocation for saline-water intrusion adaptation in the targeted institutions, staff capacity enhancement in water salinity monitoring, and provision of sophisticated equipment and technology.

Salt Desert and Saline-Ackaline Mixed Dust Storms:An Ignored Issure for Global Climate Change

Salt desert,saline-alkaline dust storm and saline-alkaline mixed dust storm are significant but ignored problems for a long time.After many years of observations and researches,the author believes that salt desert,saline-alkaline dust

Evaluation of reservoir environment by chemical properties of reservoir water‒A case study of Chang 6 reservoir in Ansai oilfield,Ordos Basin,China

The Ordos Basin is the largest continental multi-energy mineral basin in China,which is rich in coal,oil and gas,and uranium resources.The exploitation of mineral resources is closely related to reservoir water.The chemical properties of reservoir water are very important for reservoir evaluation and are significant indicators of the sealing of reservoir oil and gas resources.Therefore,the caprock of the Chang 6 reservoir in the Yanchang Formation was evaluated.The authors tested and analyzed the chemical characteristics of water samples selected from 30 wells in the Chang 6 reservoir of Ansai Oilfield in the Ordos Basin.The results show that the Chang 6 reservoir water in Ansai Oilfield is dominated by calcium-chloride water type with a sodium chloride coefficient of generally less than 0.5.The chloride magnesium coefficients are between 33.7 and 925.5,most of which are greater than 200.The desulfurization coefficients range from 0.21 to 13.4,with an average of 2.227.The carbonate balance coefficients are mainly concentrated below 0.01,with an average of 0.008.The calcium and magnesium coefficients are between 0.08 and 0.003,with an average of 0.01.Combined with the characteristics of the four-corner layout of the reservoir water,the above results show that the graphics are basically consistent.The study indicates that the Chang 6 reservoir in Ansai Oilfield in the Ordos Basin is a favorable block for oil and gas storage with good sealing properties,great preservation conditions of oil and gas,and high pore connectivity.

1973—2017年西藏盐湖湖面动态变迁及对气候波动的响应

西藏是我国主要盐湖成盐区之一,蕴藏着丰富的矿产资源。应用遥感和地理信息系统技术,从5个时间段的Landsat遥感影像中提取了西藏面积大于20 km^(2)的93个盐湖(不包括干盐湖),影像成像时间分别为1973—1977年、1990年前后、2000年前后、2010年前后和2017年,建立了西藏盐湖空间数据库,并分析了其1973—2017年的变化趋势。结论为:(1)总体上盐湖总面积呈增加趋势,且2000年之后,盐湖扩张趋势加剧,至2017年,被研究盐湖总面积已增至1990年前后的1.68倍。(2)从20世纪70年代至90年代,西藏中北部盐湖呈萎缩趋势,其余地区扩张。(3)盐湖湖面变迁与气候波动密切相关,1971—1990年气温和降雨量波动不大,引起西藏中北部盐湖萎缩的主要原因为冰川和冰雪融水补给的减少;1991—2017年气温升高降雨量增加、蒸发量减少,导致西藏盐湖呈现全面扩张的趋势。(4)扎布耶盐湖湖面动态变迁遥感解译结果与扎布耶长期观测站水位观测数据基本一致。1973—2009年其水位整体上呈波动式上升的趋势,而从2009年开始有所下降。landsat8从2013年开始免费提供多时相的遥感影像,可做西藏盐湖动态变迁的持续观测。盐湖水深和成分应作为以后重点解决的问题。

拟穴青蟹对盐度变化的生态适应及渗透调节机制研究进展

拟穴青蟹(Scylla paramamosain)属节肢动物门(Arthropoda)、软甲纲(Malacostraca)、十足目(Decapoda)、梭子蟹科(Portunidae)、青蟹属(Scylla),其野生种群主要分布于中国东南沿海和其他印度洋-太平洋海域,是中国传统海水养殖蟹类之一。该蟹个体大、生长速度快、肉质鲜美、营养丰富,且具有较高的经济价值。人们对青蟹的需求呈现上升趋势,仅通过海捕天然蟹苗或增加养殖密度,难以达到预期的产量,且不具有可持续性。合理规划拟穴青蟹养殖区域,拓展养殖空间,是推动青蟹产业迅速发展、扩大生产规模的有力举措。目前,青蟹养殖还未充分利用河口和沿岸地区众多亟待开发的不同盐度水域。结合国内外有关研究报道,总结了青蟹对盐度变化的生态适应性,尤其是盐度对青蟹生长发育的影响,并分析其渗透调节的分子机制,为不同盐度水域养殖推广,以及青蟹耐盐等新品种的开发提供参考。

含盐液滴运动传热传质特性及其影响因素

船舶在极地等气候寒冷恶劣的海上环境航行时,海水飞沫易导致其上层结构结冰,严重时对船舶航行及室外环境作业安全造成威胁。准确预测海水飞沫结冰,对确保极地区域安全作业具有重要意义。海水飞沫结冰和纯水飞溅结冰的主要区别在于盐度对结冰的影响,对于结冰问题,通常将海水飞沫简化为含盐的液态水滴(即含盐液滴,简称液滴)。数值模拟是研究含盐液滴结冰的重要手段,含盐液滴运动-传热传质过程是其结冰数值模拟的关键环节,决定了液滴撞击特性及与结冰相关的撞击液滴的物理量。本文在SHIPICE传热模型的基础上,提出了含盐液滴在运动过程中考虑质量损失及盐度变化的传热传质耦合模型;基于NNW-ICE平台,发展了拉格朗日框架下含盐液滴运动-传热传质耦合数值计算方法并开发了相应计算程序,实现了含盐液滴运动-传热传质过程的模拟;探究了含盐液滴运动-传热传质过程中的关键影响因素,系统分析了不同来流速度、温度、相对湿度和液滴粒径条件下的传热传质效应,为进一步发展含盐液滴结冰数值计算方法奠定了基础。

配制水阳离子变化对聚合物溶液黏度的影响

聚合物溶液的黏度是影响其驱油效果的重要指标。由于水源更换导致整体水质改变,对某采油厂聚合物配制影响较大。为研究水质变化对配制聚合物溶液黏度的影响,通过检测分析某采油厂三座配制站现场水和三处水源地水质情况,以及对比现场清水与模拟水配制的聚合物溶液初始黏度及厌氧放置90天的黏度保留率,确定配制水金属阳离子含量及矿化度升高,是导致生产现场聚合物溶液黏度下降的主要原因。通过对比不同浓度金属阳离子溶液配制的聚合物溶液黏度,得出金属阳离子对现场聚合物溶液黏度的影响顺序为Fe^(2+)>Fe^(3+)>Mg^(2+)>Ca^(2+)>Na^(+)>K^(+),生产中应确保Fe^(2+)含量最高不超过0.5mg/L,Fe^(3+)含量最高不超过2mg/L。在仅考虑Na^(+)、Ca^(2+)、Mg^(2+)含量的条件下,结合正交实验,确定三处水源地的来水配比约为5:1:4时,配制的聚合物溶液黏度可恢复至水质改变前的水平。