Impact of climate change on potential habitat distribution of Sciaenidae in the coastal waters of China

Climate change has affected and will continue to affect the spatial distribution patterns of marine organisms.To understand the impact of climate change on the distribution patterns and species richness of the Sciaenidae in China’s coastal waters,the maximum entropy model was used to combine six environmental factors and predict the potential distribution of 12 major species of Sciaenidae by 2050s under Representative Concentration Pathways(RCPs)2.6 and 8.5.The results showed that the average area under the receiver operating characteristic curve of the model was 0.917,indicating that the model predictions were accurate and reliable.The main driving factors affecting the potential distribution of these fishes were dissolved oxygen,salinity,and sea surface temperature(SST).There was an overall northward shift in the potential habitat areas of these fishes under the two climate scenarios.The total potential habitat areas of Larimichthys polyactis,Pennahia argentata,and Pennahia pawak decreased under both climate scenarios,while the total habitat area of Johnius belengerii,Pennahia anea,Miichthys miiuy,Collichthys lucidus,and Collichthys niveatus increased,suggesting that these might be loser and winner species,respectively.The expansion rate,contraction rate,degree of centroid change,and species richness in the potential habitats were generally more significant under RCP8.5 than RCP2.6.The mean shift rates of the potential distribution were 41.50 km/(10 a) and 29.20 km/(10 a) under RCP8.5 and RCP2.6,respectively.The changes in Sciaenidae species richness under climate change were bounded by the Changjiang River Estuary waters,with obvious north-south differences.Some waters with increased species richness may become refuges for Sciaenidae fishes under climate change.The richness and habitat area change rate of some aquatic germplasm resources will decrease,meanings that these reserves are more sensitive to climate change,and more attention should be paid to the potential challenges and opportunities for fishery managers.This study may provide a scientific basis for the management and conservation of Sciaenidae in China under climate change.

Prediction of the joint impacts of sea level rise and land development on distribution patterns of mangrove communities

Mangrove distribution along shorelines shows distinct zonation patterns;thus,different communities may face various influences from sea level rise(SLR)and land use.However,long-term change predictions are usually based only on the total extent of mangroves.Few studies have revealed how SLR and land development such as agriculture,aquaculture,and urbanization jointly affect different intertidal mangrove communities.This study proposed a novel framework combining SLAMM(Sea Level Affecting Marshes Model)and the CLUE-S(Conversion of Land Use and its Effect at Small regional extent)model to assess the potential impacts on upper and lower intertidal mangrove communities.Maoweihai in Guangxi,China,was selected as the study area and the potential impacts from the squeeze effect and mangrove expansion potential were evaluated.We established three scenarios combining SLR and land use patterns to predict mangrove coverage projections by 2070.The results showed that,under a single SLR driver,the upper intertidal mangroves would be more adaptive to rapid SLR than the lower intertidal mangroves.However,under the combined influence of the two drivers,the upper intertidal mangroves would experience larger squeeze effects than the lower intertidal mangroves,with up to 80.5%of suitable habitat lost.Moreover,the expansion potential of upper intertidal mangroves would be considerably more limited than that of lower intertidal mangroves.The length of the expandable habitat patch boundary of upper intertidal mangroves only reached 1.4–1.8 km,while that of the lower intertidal mangroves reached up to99.2–111.2 km.Further,we found that aquaculture ponds and cropland are the top two land development types that could occupy suitable habitat and restrict the mangrove expansion potential.Our results highlight that timely improvement of land use policies to create available landward accommodation space for mangrove migration is essential to maintain the coverage and diversity of mangrove communities under SLR.The proposed method can be a helpful tool for adaptive mangrove conservation and management under climate change.

Geochemical characteristics of soil gas in the Yanhuai basin,northern China

The geochemical backgrounds and origins of soil gases in the Yanhuai basin are discussed based on the regional seismogeological data and concentrations of Rn, Hg, CO2, H2, He and CH4 in soil gas measured at 422 investigating sites in field during September to October 2007. The geochemical background values of Rn, Hg, CO2, H2, He and CH4 are （8105.8±5937.4） Bq/m^3, （9.7±5.8） ng/m^3, （395.9±35.3）×10^-6, （4.0±2.3）×10^-6, （15.9±10.4）×10^-6 and （12.7±8.1）×10^-6, respectively. The geochemical backgrounds of the soil gases are higher in the eastern part of the Yanhuai basin. The main factors affecting the gasgeochemical backgrounds are gaseous origins, structure of the crust, faults, straaun and microbe activity. The higher values of gasgeochemical backgrounds in the eastern part are attributed to the existence of low-velocity zones in the upper crust, stronger tectonic activity and more contributions of Hg and He derived from the deep-earth and Rn origi- nated from granite, corresponding to stronger seismic activity. The results can be applied to identifying seismic precursor from monitoring data of gases in the studied area.

Connectivity of fish assemblages along the mangrove-seagrasscoral reef continuum in Wenchang, China

Understanding the connectivity of fish among different typical habitats is important for conducting ecosystembased management, particularly when designing marine protected areas(MPA) or setting MPA networks. To clarify of connectivity among mangrove, seagrass beds, and coral reef habitats in Wenchang, Hainan Province,China, the fish community structure was studied in wet and dry seasons of 2018. Gill nets were placed across the three habitat types, and the number of species, individuals, and body size of individual fish were recorded. In total, 3 815 individuals belonging to 154 species of 57 families were collected. The highest number of individuals and species was documented in mangroves(117 species, 2 623 individuals), followed by coral reefs(61 species,438 individuals) and seagrass beds(46 species, 754 individuals). The similarity tests revealed highly significant differences among the three habitats. Approximately 23.4% species used two habitats and 11.0% species used three habitats. A significant difference(p<0.05) in habitat use among eight species(Mugil cephalus, Gerres oblongus, Siganus fuscescens, Terapon jarbua, Sillago maculata, Upeneus tragula, Lutjanus russellii, and Monacanthus chinensis) was detected, with a clear ontogenetic shift in habitat use from mangrove or seagrass beds to coral reefs. The similarity indices suggested that fish assemblages can be divided into three large groups namely coral, seagrass, and mangrove habitat types. This study demonstrated that connectivity exists between mangrove–seagrass–coral reef continuum in Wenchang area;therefore, we recommend that fish connectivity should be considered when designing MPAs or MPA network where possible.

High pressure geochemistry:Preface

The origin and history of the Earth are manifested as the evolutionary processes of chemistry and physics of its interiors,which can be recognized by deciphering the geochemical signals recorded in minerals and rocks.Deep interiors of the Earth and other rocky planets are under both extreme pressure and temperature,i.e.,approximately 360 gigapascals(GPa)and as high as 7000 K at the center of the Earth.

中国海洋生物地理学研究进展和热点:物种分布模型及其应用

海洋生物地理学是研究海洋生物地理分布时空格局、形成过程及其影响因素的学科,对于生物多样性保护、生态系统结构稳定以及海洋资源可持续利用具有重要支撑作用。物种分布模型是研究物种地理分布变化的重要手段,其发展对于海洋生物地理学的发展具有重要的推动作用。本文综述了中国海洋生物地理学的发展历程和现状;提供了物种分布模型的定义、类型、发展历程及相关重要数据库;整理分析了中国海洋生物地理学研究中的部分热点问题,主要涉及全球变化下海洋生物分布区变化、海洋生物谱系地理结构、海洋生物入侵、种群连通性、海洋保护规划、海洋生态修复、海洋生物对极端环境适应、海洋渔业资源管理和海水养殖规划等。本文同时对海洋生物地理学研究的未来发展进行了展望,强调了改进物种分布模型的重要性,提出要强化环境和生物数据库建设,加强海洋生物地理学与其他学科的交叉融合等。本综述对于今后我国海洋生物地理学的研究,尤其是物种分布模型在相关领域中的应用具有参考价值。

Relationships between sagittal otolith size and body size of Terapon jarbua (Teleostei, Terapontidae) in Malaysian waters

Length-weight relationship provides basic information of a fi sh’s condition while the morphometric data of otolith has been traditionally used to determine the range of fi sh sizes for various purposes.The length-weight relationship of Terapon jarbua(Forskål,1775)was examined from 165 specimens,while 132 specimens were used in sagittal otolith biometry measurements.Fish specimens were obtained from various locations in Malaysia including Pahang,Selangor,Sarawak,and Sabah.The total length of fi sh ranged 12.5–32.5 cm,while the total weight ranged 26.28–444.30 g.The otolith length ranged 0.423–1.070 cm,and the otolith weight was 0.0103–0.1572 g.The specimens displayed a mixture of positive and negative allometry growth as indicated by fl uctuating b values between 2.74 and 3.15.The overall coeffi cient of determination(R 2)between fi sh length and weight was 0.9729,which implies a strong correlation.All regressions between the fi sh length and otolith dimensions were highly signifi cant(P<0.001).The otolith dimensions found to be most closely related to the fi sh total length was the otolith weight.This was supported by the regression model showing a high R 2 value of 86.57%.The aspect ratio of otolith was 1.80±0.14(mean±SD).Results confi rm that the otolith growth refl ects the somatic growth of T.jarbua.The length-weight relationship explained the growth conditions of the fi shes in each location while the overall b value of 2.91 indicates that the condition of T.jarbua grown in Malaysian waters during the study period was generally in good condition.This study contributed to the database on the morphometric data of otolith of T.jarbua as well as the fi rst report on fi sh length-weight relationship for T.jarbua in Malaysia.

Prediction of Potential Carbon Dioxide Emissions of Selected Emerging Economies Using Artificial Neural Network

Tackling future global emissions of carbon dioxide is a daunting task. Different black box models have been used to determine the trajectories of CO2 emissions and other carbon stocks. Trajectories are important because climate modelers use them to project future climate under higher atmospheric CO2 concentrations. In this paper, fully connected two-layer feed-forward neural network with tangent activation function that comes with hidden neurons as well as linear output neurons was used. The study applied classical nonlinear least squares algorithm such as LM (Levenberg-Marquardt), to predict potential emissions of selected emerging economies. Building the model on the basis of input variables such as crop production, livestock production, trade imports, trade exports, economic growth, renewable and nonrenewable energy consumption. These variables are considered to affect the ecosystems of high rising economic power states. The main idea is to ensure that emerging economies have a clear understanding of expected future emissions so that appropriate measures can be implemented to mitigate its impact. Data for the analysis were obtained from 1971 to 2013 from World Development Indicators and FAOSTAT database. Results indicate an achievement of training performance at epoch 11 when the value of the MSE (Mean Square Error) is 0.0003345 which indicates that the model errors are less than 0.05. Hence, the study concluded that the applied model is capable of predicting potential carbon dioxide emissions in emerging economies with the greatest precision.

Impact of Economic Growth,Energy Use and Population Growth on Carbon Emissions in Sub-Sahara Africa

The study examines the impact of economic growth,energy use and population growth on carbon emissions in sub Saharan Africa:Kenya,Nigeria,Botswana,Benin,Togo and Mauritius for the period of1990-2014.The study employed unit root test,co-integration test,VECM(Vector Error Correction Model)and FMOLS(Fully Modified Ordinary Least-Square)as methodologies to model the causality and linear relationships amongst the variables.The VECM was used to identify the long-run causality and asymptotic convergence among the variables.The results reveal that an increase in energy use and population growth by1%would cause an increase in CO2(Carbon Dioxide)concentration by0.08%and0.22%correspondingly,whereas in the long-run1%increase of energy use increases economic output by0.09%.As the economy grows without contributing to carbon emissions,governments should invest more in renewable energy.Governments should also come up with policies to regulate population growth and fossil energy use.

流体地球化学进展及其在地震预测研究中的应用

地震预测是仍未解决的世界性难题.流体地球化学是地震预测的潜在手段之一,近年来得到了较为广泛的认可与运用.地震的孕育和发生过程始终伴随着地下物质运移、能量传输和条件改变,从而导致流体中元素和同位素的迁移与演化,进而形成地表可观测到的流体地球化学异常.活动断裂带是地震多发区,同时也是深部流体运移和释放的有利通道.活动断裂带流体的地球化学特征对地壳应力、温压条件和渗透率的变化极其敏感,可以作为指示构造或地震活动的良好指标.流体地球化学与断裂活动的密切关系使得流体地球化学不仅在地震预报中发挥着重要作用,也是解释地震过程中物质来源、能量交换和条件变化的有效手段.此外,新的地球化学分析技术的迅速发展,使其在研究地震前兆机理和地震物理过程中发挥越来越重要的作用.本文在综述近年来流体地球化学在地震预测领域研究进展的基础上,结合自身团队的研究结果和认识,提出未来地震地球化学研究的发展方向.

海洋生境制图研究进展:概念、方法与应用

基于生态系统的海洋管理采用生态边界而非行政边界来指导管理实践,海洋生境制图旨在探寻海洋环境与生物群落/物种的分布规律,从而为生物多样性保护和海洋空间规划等管理行动提供可以依循的生态边界。海洋生境制图是科研监测数据通往管理决策应用的有效途径,近年来已成为海洋生态保护与管理领域的国际研究热点,但我国对于海洋生境制图的研究才刚刚起步。本文对海洋生境制图的国内外研究进展进行了综述,介绍了海洋生境制图的定义和内涵,明确了海洋生境制图的步骤及其在生态系统管理中的应用;系统阐述了海洋生境制图的主要研究方法,从生境分类方案、生境分区和生态特征描述等方面对海洋生境制图的研究过程及采用的分析方法进行了总结;全面梳理了国内外的代表性海洋生境制图研究案例,对各国已开发的海洋生境分类分区体系进行了对比和评述,总结了共性特征;最后提出研究建议,对我国开展海洋生境制图研究的前景进行展望,以期为我国的海洋生态空间管理工作提供科学依据和参考。

Seagrass meadows provide multiple benefits to adjacent coral reefs through various microhabitat functions

Tropical seagrass meadows and coral reefs often function as interconnected marine habitats,but they are often studied and managed as homogenous units.As macrohabitats,seagrass meadows provide important benefits to adjacent reef ecosystems by acting as natural filters of sediments and nutrients,and by providing critical feeding,nursery,and refuge habitats for reef fishes and other fauna.Whilst the macrohabitat functions of seagrass meadows have been often acknowledged,their microhabitats functions have largely been neglected.The purpose of the study is to explore how seagrass meadows provide multiple benefits to adjacent coral reefs through various microhabitat functions.The paper reveals some of the diversity of microhabitats that seagrass meadows contain,such as macroalgal mats,rubble cavities,sand patches with sparse seagrass,anemone gardens,hard substratum,and sponges mixed with seagrass.We highlight the ways in which reef creatures have diversified and specialized in using these different microhabitats,and postulate that seagrass microhabitat diversity enhances the habitat function and faunal diversity of seagrass meadows.