<Emphasis Type="Italic">Phragmites australis</Emphasis> (Common Reed) Invasion in the Rhode River Subestuary of the Chesapeake Bay: Disentangling the Effects of Foliar Nutrients,Genetic Diversity,Patch Size,and Seed Viability

The invasion and expansion of the introduced haplotype of Phragmites australis across North America is of growing concern. Previous studies in the Chesapeake Bay region found that Phragmites was more abundant, had higher foliar nitrogen, and produced more viable seeds in brackish wetland subestuaries with more anthropogenic development of the watershed. Here, we focus on a different scale and address issues related to the invasion of Phragmites within a single subestuary, the Rhode River. We evaluated patterns in seed viability, foliar nutrient concentrations, patch size, and genetic variation in ten Phragmites patches in wetlands that occur in the side of the subestuary that is surrounded by forest and 10 patches in wetlands that are in the side of the subestuary that has extensive anthropogenic development. Seed viability varied from 0–60% among the 20 patches but did not differ significantly between patches on the developed vs. forested sides of the Rhode River. Foliar nutrients also did not differ between patches on the two sides of the Rhode River. Seed viability, however, was negatively related to foliar nutrients. Most Phragmites patches consisted of >1 genotype. Larger patches had multiple genotypes, and patches with more genotypes produced more viable seeds. Our study indicates that the Rhode River subestuary behaves as one system with no differences in the measured Phragmites variables between the forested vs. developed sides of the watershed. Our findings also suggest a cyclical process by which Phragmites can spread: larger patches contain more genetic diversity, which increases the chances for cross-fertilization. The subsequent increased production of viable seeds can increase local levels of genetic diversity, which can further facilitate the spread of Phragmites by seed.     

Effects of salinity downshock on dimethylsulfide production

During time-series observations in Sagami Bay, Japan, the concentration of dissolved dimethylsulfoniopropionate (DMSP_d), a precursor of dimethylsulfide (DMS), was negatively correlated with salinity. In the laboratory, low-salinity shock reduced DMS production rates of the natural bacterial community and induced rapid DMSP release from a dinophyte, Heterocapsa triquetra, suggesting that low-salinity shock reduced DMSP_d consumption but enhanced DMSP_d production, which agrees with the negative correlation between DMSP_d and salinity observed in Sagami bay. In addition, low-salinity shock did not affect DMSP lyase activity of H. triquetra. Low-salinity shock would increase the contribution from algae in DMS production, leading to an increase in potential DMS productivity in the environment.     

Paleoproterozoic quartz-pebble conglomerate type uranium mineralisation in Mankarhachua area,Angul district,Orissa

Ground Radiometric survey of Paleoproterozoic pyritiferous quartz-pebble conglomerate (QPC) occurring to the north of Pallahara area led to the discovery of a QPC type uranium mineralisation near Mankarhachua village. Significant radioactivity is recorded in three sub-parallel uraniferous QPC horizons with metamorphosed pebbly to medium grained recrystallised massive sandstones. Detrital grains of uranothorite, thorite, radioactive allanite, monazite, zircon, minute uraninite grains in carbonaceous matter and thucolite contributes to the radioactive phases present in QPC matrix. Adsorbed U on limonite and goethite, secondary uranyl minerals in matrix, along bedding planes and fractures are commonly observed. This discovery has opened up a new horizon for future exploration for QPC type uranium mineralization in the area. The paper presents observations on geology, radioactivity, petrological and geochemical nature of the uraniferous QPC horizons.     

Mid and late Holocene forest fires and deforestation in the subalpine belt of the Iberian range,northern Spain

The conversion of subalpine forests into grasslands for pastoral use is a well-knownphenomenon, although for most mountain areas the timing of deforestation has not been determined. The presence of charcoal fragments in soil profiles affected by shallow landsliding enabled us to date the occurrence of fires and the periods of conversion ofsubalpine forest into grasslands in the Urbión Mountains, Iberian Range, Spain. We found that the treeline in the highest parts of the northwestern massifs of the Iberian Range(the Urbión, Demanda, Neila, and Cebollera massifs) is currently between 1500 and 1600 m a.s.l., probably because of pastoral use of the subalpine belt, whereas in the past it would have reached almost the highest divides(at approximately 2100–2200 m a.s.l.). The radiocarbon dates obtained indicate that the transformation of the subalpine belt occurred during the Late Neolithic, Chalcolithic, Bronze Age, Iron Age, and Middle Ages. Forest clearing was probably moderate during fires prior to the Middle Ages, as the small size of the sheep herds and the local character of the markets only required small clearings, and therefore more limited fires. Thus, it is likely that the forest recovered burnt areas in a few decades; this suggests the management of the forest and grasslands following a slash-andburn system. During the Middle and Modern Ages deforestation and grassland expansion affected most of the subalpine belt and coincided with the increasing prevalence of transhumance, as occurred in other mountains in the Iberian Peninsula(particularly the Pyrenees). Although the occurrence of shallow landslides following deforestation between the Neolithic and the Roman Period cannot be ruled out, the most extensive shallow landsliding processes would have occurred from the Middle Ages until recent times.     

Organized bacterial assemblies in manganese nodules: evidence for a role of S-layers in metal deposition

Polymetallic/ferro-manganese nodules (Mn-nodules) reach sizes of up to 10 cm in diameter and are abundantly found on the seabed. To date, the origin of Mn-nodules remains unclear, and both abiogenic and biogenic origins have been proposed. In search of evidence for a contribution of microbial processes to the formation of Mn-nodules, we analyzed those spherical nodules which contain a concentrically banded texture in their interior. The Mn-nodules were collected at a depth of 5,152 m from the Clarion-Clipperton Zone. Our high-resolution scanning electron microscopy analyses reveal first published evidence that endolithic microorganisms exist and are arranged in a highly organized manner on plane mineral surfaces within the nodules. These microorganisms are adorned on their surfaces with S-layers, which are indicative for bacteria. Moreover, the data suggest that these S-layers are the crystallization seeds for the mineralization process. We conclude that the mineral material of the Mn-nodule has a biogenic origin, and hope that these data will contribute to the development of biotechnological approaches to concentrate metals from seawater using bacteria in bioreactors.     

Erratum to: Assessment of coastal communities’ vulnerability to floods using indicator-based approach: a case study of Greater Accra Metropolitan Area,Ghana

In this paper, the extent to which the potentially transit-dependent portion of the population is vulnerable to the effects of a hurricane is estimated. The vulnerability of an area is defined as a composite measure of the proportion of disadvantaged persons, distance to transit, and flooding potential of people within an area. Unlike past studies which have focused on the vulnerability of the population in relatively large geographic areas, this study estimates the vulnerability of the population in 30 m × 30 m areas as defined in the National Land Cover Database. Population estimates from the national census at block level are disaggregated to the 30 m × 30 m units using a modified dasymetric mapping method in ArcGIS. The modified mapping method assigns population to each small areal unit using weights estimated by regressing the area of each land use in a census block against the population in that block. The coefficients in the regression analysis are “weights” associating population with each land use, and are used to distribute the population in each census block to the small geographic units based on their land use. In a case study of New Orleans, the results show that some areas are not well served by the existing transit pickup locations, as evidenced by their high vulnerability scores. Reassignment of pickup point locations to cover higher vulnerability score areas was investigated using integer linear programming. The results show that the optimally located pickup points serve areas with a larger average vulnerability score than the current pickup points in the study area. The method appears to be helpful in identifying vulnerable areas that, subsequently, could receive improved hurricane evacuation service in the future.     

Shell model representation as a substitute of LoD3 for 3D modeling in CityGML

The OGC standard for 3D city modeling is widely used in an increasing number of applications.It defines five consecutive Levels of Detail(LoD0 to LoD4 with increasing accuracy and structural complexity),in which LoD3 includes all exterior appearances and geometrical details and subsequently requires much storage space.A new LoD is introduced as shell model with the exterior shell of the LoD3 model and the opening objects like windows,doors as well as smaller faade objects are projected onto walls.In this paper,a user survey is presented.The results of this survey show that the shell model can give users almost the same visual impression as the LoD3 model.Furthermroe,algorithms are developed to extract the shell model from LoD3 model.Experiments show that this shell model can reduce up to 90% storage of the original LoD3 model.Therefore,on one hand it can be used as a substitute for a LoD3 model for the visualization on small displays.On the other hand,it can be treated as a sub-level of detail(SLoD3) in CityGML,since it retains almost the same amount of information but requires much less storage space.     

Soil organic carbon storage and soil CO<Subscript>2</Subscript> flux in the alpine meadow ecosystem

High-resolution sampling, measurements of organic carbon contents and ¹⁴C signatures of selected four soil profiles in the Haibei Station situated on the northeast Tibetan Plateau, and application of ¹⁴C tracing technology were conducted in an attempt to investigate the turnover times of soil organic carbon and the soil-CO₂ flux in the alpine meadow ecosystem. The results show that the organic carbon stored in the soils varies from 22.12×10⁴ kg C hm⁻² to 30.75×10⁴ kg C hm⁻² in the alpine meadow ecosystems, with an average of 26.86×10⁴ kg C hm⁻². Turnover times of organic carbon pools increase with depth from 45 a to 73 a in the surface soil horizon to hundreds of years or millennia or even longer at the deep soil horizons in the alpine meadow ecosystems. The soil-CO₂ flux ranges from 103.24 g C m⁻² a⁻¹ to 254.93 gC m⁻² a⁻¹, with an average of 191.23 g C m⁻² a⁻¹. The CO₂ efflux produced from microbial decomposition of organic matter varies from 73.3 g C m⁻² a⁻¹ to 181 g C m⁻² a⁻¹. More than 30% of total soil organic carbon resides in the active carbon pool and 72.8%281.23% of total CO₂ emitted from organic matter decomposition results from the topsoil horizon (from 0 cm to 10 cm) for the Kobresia meadow. Responding to global warming, the storage, volume of flow and fate of the soil organic carbon in the alpine meadow ecosystem of the Tibetan Plateau will be changed, which needs further research. Supported by the National Natural Science Foundation of China (Grant Nos. 40231015, 40471120 and 40473002) and the Guangdong Provincial Natural Science Foundation of China (Grant No. 06300102)     

Review on physical models of lunar brightness temperature

Brightness temperature is a main index to reflect the energy of microwave radiation of an object. Using lunar brightness temperature data, physical properties of lunar regolith, such as thickness, heat flow and dielectric permittivity, could be interpreted. There are two methods to study brightness temperature distribution of the moon: the first is used to measure lunar brightness temperature by radio observation or spaceborne microwave radiometers, and the second is used to simulate calculation by the physical model. On the basis of the measurements of lunar brightness temperature in the history, this study analyzed the main physical model of lunar brightness temperature, also including its theory and influence factors. The authors concluded that surface and subsurface temperatures of the moon, dielectric properties and layered structure of lunar regolith were the main factors affecting the global brightness temperature of the moon. These factors should be quantified in detail in the future research.