SR-XRF analysis of Polytrichum in the Fildes Peninsula,Antarctica

In order to study the element contents and distribution of various mosses collected in the Antarctica, we analyzed the heavy elements of 3 species of Polytri-chum in the Fildes Peninsula, P. alpinum, P. juniperinum and P. alpestre, by synchrotron radiation X-ray fluorescence ( SR-XRF). The result shows that the elements, such as K, Ca, Mn, Fe, Cu, Zn and Sr, are nearly the same in Potytrichum. The peak intensity of K is higher than that of Ca, and the peak intensity of Ca is higher than that of Fe in P. alpinum. In P. juniperinum, the peak intensity of K is higher than that of Ca, and the peak intensity of Ca is close to that of Fe. The peak intensity of K is nearly equal to those of Ca and Fe in P. alpestre. Therefore, the habitats of 3 species of Polytrichum are similar in the Fildes Peninsula. By XRF analyzing of different parts of P. alpestre, we found that the peak intensities of relative concentration of elements are obviously different. The peak intensity of K in apical-bud is the highest in orga     

Seed germination of wild,in situ-managed,and cultivated populations of columnar cacti in the Tehuacán-Cuicatlán Valley,Mexico

Seed germination was compared among wild, in situ-managed (wild plants let standing in areas cleared for agriculture), and cultivated populations of the columnar cacti Stenocereus pruinosus, Polaskia chichipe, Myrtillocactus schenckii, and Polaskia chende, species representing a gradient from higher to lower management intensity, respectively. We hypothesized that seeds from cultivated populations have higher water requirements to germinate than seeds of other populations, and that such difference is stronger in species more intensely managed. Germination was evaluated under water potential treatments at 0.0, ?0.2, and ?0.4 MPa. Interspecific differences were identified; germination rates markedly decreased in S. pruinosus and P. chichipe as water potential reduced. M. schenckii seeds germinated better at ?0.2 MPa, and seeds of P. chende in all treatments. Seed germination of wild and cultivated populations was similar in all cases and, therefore, at the population level domestication does not appear to have influenced variations in germination of the studied cacti species. However, experiments to test whether germination of seeds from plants with clear signs of domestication differs with seeds from other plants and their differential germination and seedling survival in wild, in situ-managed and cultivated environments could help to precise the influence of domestication on these plants.     

Self－organization phenomena of the nonequilibrium process in magmatism of the Fildes Peninsula， West Antarctica

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Environmental changes in the Zirahuén Basin, Michoacán, Mexico, during the last 1000 years

Lago de Zirahuén (19° 26 N, 101° 44 W) lies within a montane basin in highland Michoacán, Mexico at 2075 m a.s.l. The lake basin has high recreational value and is promoted as a tourist attraction. Four short (<1 m), sediment–water interface cores were used to investigate Late Holocene environmental change. The cores span approximately the last 1000 years, based on ²¹⁰Pb dating, AMS ¹⁴C dating and tephrochronology. Cesium-137, Americium-241 and tephra layers from Volcan Paricutín (AD 1943–1952) and Volcan Jorullo (AD 1759–1774) provide independent age markers. Cores were analysed for diatoms, magnetic susceptibility and heavy metals (iron, lead, manganese, copper and zinc). Drier climate around 1000 years BP is tentatively inferred from the diatom assemblage and is concordant with other regional records. Increased soil erosion between ca. AD 1100 and AD 1550 may be associated with Pre-Hispanic settlement in the basin, but there is no archaeological evidence to support this. A period of catchment stability occurred during the early Colonial Period, ca. AD 1550–1750. The dramatic decline in the indigenous population following the Spanish Conquest in 1521 may have promoted vegetation recovery on the basin slopes. After the mid-18th century, a significant change in diatom species composition is observed along with an increase in soil erosion, as inferred from the magnetic susceptibility profile. Concentrations of copper and lead also increased. These changes are associated with the establishment of a copper smelting industry in the basin and increased Colonial agricultural development. Recently, tourist developments and commercial agriculture have impacted on the basin. The diatom flora has changed dramatically in the last 20 years, apparently in response to the onset of cultural eutrophication. The palaeoenvironmental evidence suggests that the lake is responding rapidly to land use intensification in the basin, which may have implications for future developments.     

The MaB Reserve of Ñacuñán,Argentina: its role in understanding the Monte Desert biome

Temperate and semi-arid regions of Argentina are undergoing rapid habitat conversion as a result of several human activities (i.e. grazing, logging, agriculture, etc.). These arid ecosystems contain many endemic species and have played an important role in the evolution of South American biota. The Man and Biosphere Reserve of Ñacuñán (12,800 ha) is located in the central region of the lowland Monte Desert. The reserve is a stand within a highly disturbed matrix characterized by deforestation (i.e. mesquite,Prosopis)and overgrazing. Major vegetational and animal communities recovered after the reserve was fenced in 1972, and Ñacuñán thus provides critical data describing the recovery of biotic and abiotic components of the Monte Desert when anthropogenic assaults are minimized. Indeed, the Reserve of Ñacuñán protects many distinctive habitats of the Monte Desert, including mesquite forest, or algarrobal, and several representative animals of the South American biota (i.e. tinamous, rhea, marsupials, edentates and caviomorph rodents). Several research projects on community ecology, herbivory, disturbances, ecology and ecophysiology have been or are being developed in the reserve. Although the town of Ñacuñán lies within the reserve, the link between the research community and the local people has not been strong, persistent or effective. The reserve is the most important site in Argentina for monitoring the ecological health of the Monte Desert and for developing indicators of desertification. Its potential is great for long-term ecological research and for strengthening the infrastructure of science. Sustainable development in the next millennium requires integrating the activities of the research, local people, ranch landowners and governmental sectors so as to infuse science-based proposals into management and conservation initiatives.     

Influence of the interactions within the water – earth materials system on the formation of river water composition in the Ob basin

Physicochemical calculations of the abundance of a number of minerals and organo-mineral compounds in the river waters of the Ob basin revealed that the river waters throughout a year are able to actively interact with bottom sediments and river loads. The most active interactions occur in areas and during periods with increased moduli of river flow. It is shown that the increase in concentrations of dissolved organic matter in the river waters, including in the case of waste water discharges, is limited to a relatively low solubility of a number of compounds of metals with carbonates and humic acids.     

The pedogenic groups and diagnostic characteristics in the Fildes Peninsula of King George Island， Antarctica

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Geomorphology of the Boao coastal system and potential effects of human activities -Hainan Island, South China

1 IntroductionThe objectives of this paper are to analyze the principal characteristics of the W anquan Riverdelta that has developed in a narrow , shallow lagoon, and to determ ine the effect that theever-increasing hum an activities of the area m ay hav…     

Late Quaternary (24–10 ka BP) environmental history of the Neotropical lowlands inferred from ostracodes in sediments of Lago Petén Itzá, Guatemala

We inferred late Pleistocene and early Holocene (24–10 ka BP) environmental conditions in and around Lago Petén Itzá, Guatemala from ostracode remains in the lake sediments. Multivariate statistics were run on autecological information for 29 extant ostracode species collected in 63 aquatic ecosystems on the Yucatán Peninsula along a steep, increasing NW–S precipitation gradient and across a large altitudinal range. Conductivity and water depth are the most important factors that shape ostracode communities. Transfer functions were developed and applied to fossil ostracode assemblages in a ~76-m sediment core (PI-6, ~85 ka) taken in 71 m of water from Lago Petén Itzá, to infer past shifts in conductivity and water level. Results suggest climate was cold and wet during the Last Glacial Maximum (LGM). Alternating dry and wet conditions characterized the deglacial. Early Holocene climate was warmer and wetter. The LGM was characterized by low ostracode species richness (4 spp.) and abundance (<940 valves g⁻¹), dominance of benthic over nektobenthic taxa, abundant Physocypria globula, conductivity as low as 190 μS cm⁻¹, and clay-rich sediments with relatively high total organic carbon and low C/N ratios (<14), suggesting relatively deeper water at the core site associated with abundant precipitation. Greatest water depth at the core site during the LGM occurred late in the period and was ~50 m. The deglacial was characterized by drier conditions, higher ostracode species richness (6 spp.) and abundances up to 18,115 valves g⁻¹, dominance of nektobenthic species, and presence of shallow-water and littoral-zone indicators such as Heterocypris punctata and Strandesia intrepida, conductivity up to 550 μS cm⁻¹, C/N ratios as high as 37, and gypsum deposition. Lowest inferred lake depth at the core site during the deglacial was ~20 m. The early Holocene was characterized by high numbers of ostracode remains, up to 25,500 valves g⁻¹, and the presence of L. opesta and P. globula. Cytheridella ilosvayi was absent from late Pleistocene sediments, suggesting it colonized northern Central America during the Holocene.     

Investigating the geomorphic characteristics of an Amazonian headwater stream draining a páramo ecosystem

Páramos are neotropical alpine grasslands located in the northern Andes of South America. Although they cover important headwater regions, little is known about the hydro-geomorphic characteristics of páramo river systems, which are increasingly being impacted by human use and climate change. The objective of this research is to characterize the geomorphology of the Ningar River, Ecuador, an Amazonian headwater river that drains a 22.7 km2 páramo sub-basin, by (1) classifying the geomorphology based on common geomorphic classifications, (2) deriving downstream hydraulic geometry relationships, and (3) performing a global comparison with mountain river systems. Common geomorphic field surveying techniques were used to acquire the necessary data. Results suggest that the Ningar River has similar form-function characteristics as other known mountain headwater streams and corresponds to commonly known stream classification systems, but displays more of an alluvial character than might be expected for montane headwater streams as a result of a convexity in the stream’s longitudinal profile. Additionally, preliminary analyses suggest that other páramo headwater streams may exhibit similar characteristics; thus, the findings of this research are important for future management and protection of these valuable headwater ecosystems.     

Environmental and ecological water requirement of river system: a case study of Haihe-Luanhe river system

1 IntroductionRiver system, to some extent, can be regarded as an independent eco-system, which includes river channels, lakes and the lands near the water bodies. In the engineering view, river system can be defined as the flooded area with a flood frequency of 1%[1,2]. The major aspects of the river system may be its water quantity, water quality and aquatic species. The three aspects of the system have a close relation with each other. The river system has a lot of functions, of which in g…     

Relationships between variations of the land–ocean–atmosphere system of northeastern Asia and northwestern North America

This study is a broad-scale synthesis of information on climate changes in two Arctic terrestrial regions, eastern Siberia and the Alaska–Yukon area of North America. Over the past 60 years (1951–2010), the trends of temperature and precipitation in the two regions are broadly similar in their seasonality. However, atmospheric advection influences the two regions differently during winter. The differential advective effects are much weaker in the other seasons. The Pacific Decadal Oscillation is the strongest correlator with interannual variability in the two regions, followed by the Arctic Oscillation and the El Niño/Southern Oscillation.Projected changes by the late 21st Century are qualitatively similar to the changes that have been ongoing over the past 60 years, although the rate of change increases modestly under mid-range forcing scenarios (e.g., the A1B scenario). The greatest warming is projected to occur farther north over the Arctic Ocean in response to sea ice loss. Precipitation is projected to increase by all models, although increases in evapotranspiration preclude conclusions about trends toward wetter or drier land surface conditions. A notable feature of the future climate simulations is a strong maximum of pressure decreases in the Bering Sea region, implying further advective changes.     

Spatial concentration and variability of rainfall in the Iguaçu River Basin,State of Paraná−Brazil

The analysis of rainfall as an environmental factor that influences landscape dynamics is an important and ongoing topic of discussion. This discussion can be centred on the discovery of impacts caused by the increase or decrease in rainfall frequency and intensity. From this perspective, this study sought to analyse the rainfall variability in the Iguaçu River basin, located in the State of Paraná, southern Brazil. The main objective was focused on the temporal-spatial rainfall distribution in the study area and its interaction with landscape dynamics (different land uses). Precipitation data for the period 1988−2018 were obtained from the ‘Águas Paraná’ Institute. To calculate the Concentration Index−CI values of the study area, data analysis was performed using the ‘R’ software with Climatol and Precindicon subroutines of the software, and analysis of Landsat 8 satellite images through ArcGIS. The results indicated that there was a well-defined spatial variability in the study area, as the CIs defined higher rainfall concentrations upstream from the river basin and lower rainfall concentrations downstream—implying that these processes may be strongly associated with land use.     

Green Laboratories: University Campuses as Sustainability “Exemplars” in the Arabian Peninsula

ABSTRACT

Like many universities in the West, universities across the Arabian Peninsula are increasingly home to various conspicuous sustainability initiatives. This article examines this trend at three of the region’s most prominent projects: NYU-Abu Dhabi in the Emirates, Qatar Foundation’s Education City, and Saudi Arabia’s King Abdullah University of Science and Technology. Based on the textual analysis and informed by fieldwork in these countries since 2012, this article joins interdisciplinary research in political geography, sustainability experimentation, and laboratory studies to understand their iconic campuses not as enclaves, but as “exemplars” of sustainability and renewable energy futures in the region. Tracing their effects beyond their walls, I argue that they have mostly been limited to symbolically injecting sustainability into public discourse. While more substantial shifts toward sustainable development in the region are underway, these have largely stemmed from market forces rather than a new environmental consciousness promoted by these three iconic universities.     

The San Nicolás succession of the Cauca paleolake: a late Holocene laminated ria lake record from the Neotropics

The stratigraphic, geochemical, and organic matter study of the late Holocene San Nicolás succession of the Cauca paleolake (Santa Fé–Sopetrán pull-apart basin) in the middle Cauca Valley, northern Colombia, suggests that it was deposited in a ria lake environment, at sedimentary accumulation rates in excess of 600 cm ky^?1 between ~3500 and ~500 yr BP. Laminated deposition occurred, first under igapo (black-water), and then under varzea (white-water) conditions. The transition occurred ca. 3000 yr BP, a time of major change in El Niño/Southern Oscillation (ENSO) behavior in the Cariaco Basin, thus reflecting the southern migration of the intertropical convergence zone and intensified rain upstream the Cauca Valley. A second, but less conspicuous change occurred ca. 2000 yr BP, which apparently corresponds to the intensified and/or more frequent ENSO activity in the Galapagos Islands. Our contribution describes, for the first time, a ria lake sedimentary succession from the northern Andes and demonstrates the high potential of these hitherto undervalued deposits for the reconstruction of the paleohydrological history of the northern Andes.     

A group velocity of seismic love surface wave and lithosphere structure in Antarctic Peninsula

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Adaptive evolution of the rural human–environment system in farming and pastoral areas of northern China from 1952–2017

The theory on the cyclic adaptation between society and ecosystems sheds new light on the evolution and internal structure of human–environment systems. This paper introduces the risk index(RI) and adaptation capacity index(ACI) to evaluate the rural human–environment system. An evaluation index system for the adaptability of rural human–environment systems is configured in the context of climate change and policy implementation. On this basis, the stages, features, dominant control factors, and evolution mechanism were examined vis-à-vis the adaptability of the rural human–environment system in Darhan Muminggan Joint Banner from 1952 to 2017. The main results are as follows:(1) The evolution of the rural human–environment system can be divided into three stages, namely, the reorganization and rapid development stage(1952–2002) with population, cultivated land, livestock and degraded grassland increasing by 260%, 13%, 134% and 16.33%, respectively. The rapid to stable development stage(2003–2010) with population increasing by 2.8%; cultivated land, livestock and degraded grassland decreasing by 2.3%, 13.6% and 10.7%, respectively. The stable to release stage(2011–2017) with population, cultivated land, livestock and degraded grassland decreasing by 2.6%, 0.2%, 10.6% and 3.8%, respectively.(2) With the passage of time, the ACI of the rural human–environment system first increased slightly(–0.016–0.031), followed by a slight decline(0.031–0.003), and culminating in a rapid increase(0.003–0.088). In terms of spatial patterns, adaptability is high in the middle, moderate in the north, and low in the south.(3) The evolution of adaptability in the rural human–environment system was mainly controlled by the per capita effective irrigation area(22.31%) and the per capita number of livestock(23.47%) from 1990 to 2000, the desertified area(25.06%) and the land use intensity(21.27%) from 2000 to 2005, and the per capita income of farmers and herdsmen(20.08%) and the per capita number of livestock(18.52%) from 2010 to 2007.(4) Under the effects of climate change and policy interventions, the cyclic adaptation of the rural human–environment system was propelled by the interactions between two kinds of subjects: farmers and herdsmen on the one hand and rural communities on the other hand. The interaction affects the adaptive behavior of the two kinds of subjects, which in turn drives the cyclic evolution of the system. As a result, the system structure and functions developed alternatively between coordinated and uncoordinated states. Small-scale adaptive behaviors of farmers and herdsmen have a profound impact on the evolution of the rural human–environment system.     

An environmental decision‐support system for the management of water pollution in a tidal river network

This paper is about the development of a decision‐support system for water‐pollution management and environmental planning. More specifically, the paper first presents the overall concept and the system architecture of a generic environmental decision‐support system (EDSS) and then develops an EDSS especially for analysing the tidal flow pattern and water quality of China's Pearl River Delta. The EDSS developed here employs the object‐oriented approach to design the environmental database and utilizes the system integration technology to develop the overall user‐friendly system that operates in the Windows environment. Furthermore, the system can be expanded to facilitate automated model selection and analysis. The EDSS should be of value for managing water quality of river networks with complicated flow patterns, such as that found in the Pearl River Delta.     

Annual growth zones in stems of Hypericum irazuense (Guttiferae) in the Costa Rican páramos

The high peaks of the Cordillera de Talamanca in Costa Rica support shrub- and grass-dominated páramo ecosystems that experience stand-replacing wildfires. The dry season that facilitates these fires results in dormancy in plant growth and provides an opportunity to use dendrochronological analyses to determine ages of plants in burn sites to support studies of fire history and postfire vegetation recovery. This study investigates the formation of annual growth zones in stems of the common shrub Hypericum irazuense. Unlike other páramo shrubs, H. irazuense rarely resprouts following fire, instead recovering through seedling recruitment following seed dispersal from the unburned periphery. Laboratory analysis of 19 prepared cross sections from 15 stems shows that samples of H. irazuense from burned areas can provide an estimate of the minimum number of years since the previous fire, supporting earlier work based on field examination of stems. Including a time lag for seedling recruitment or resprouting refines that estimate. Counts of growth zones in most sections coincided with dates of the last known fires. The presence of annual growth zones in H. irazuense places the species within a relatively small group of woody Neotropical species for which annual rings or growth zones have been demonstrated.