Public policy and the changing landscape

The paper illustrates how spatially explicit forecasting of residential development can be undertaken and how it can be made sensitive to policy instruments available to local and state governments. Predicted values in residential use based on a hedonic analysis of residential property prices is found to have a significant effect on the hazard of development in a survival model used to explain the likelihood that a farm or forest will be converted to residential use. Policy instruments are imbedded in both the hedonic model of residential property values and a hazard model of parcel conversion, so as to test how effective changes in policies can be at changing the pattern of land-use change. Some of the statistical and modeling obstacles that impede progress on this spatially explicit modeling are also discussed.     

A water quality model for the Patuxent estuary: Current conditions and predictions under changing land-use scenarios

A water quality model was developed for the Patuxent estuary using the modeling framework CE-QUAL-W2 (called W2) to address the impact of current and projected land-use changes (stress) on the water quality. The W2 code, supported by the Army Corps of Engineers Waterways Experiment Station, is a two-dimensional (longitudinalvertical) model designed for hydrodynamic and water quality simulations of reservoirs and estuaries. The code was configured for the Patuxent estuary using a finite-difference grid for the water column. Also incorporated into the model calculations are flow and nutrient load results from a watershed model. The integrated model was calibrated with data of 1 yr from 1997 to 1998 by matching results with measured temperature, dissolved oxygen, chlorophylla, and nutrient levels in the water column. The calibrated model was used to predict the water quality effects of different watershed land-use scenarios. Model projection results suggest that reductions of nutrient loads would lead to improvement of anoxic conditions in the bottom waters of the lower Patuxent estuary.     

Depositional environment in and around Tamiraparani estuary,and off Tuticorin,Tamil Nadu,India: clues from grain size studies

The sediments of the estuaries and offshore Tuticorin along the southern coast of Tamil Nadu were studied for their textural variation. Ninety sediment samples were collected from three sectors (river, estuary, offshore) on the basis of prevailing energy conditions and oceanographic parameters. Frequency curves show unimodal to bimodal in nature. Offshore samples also fall in bimodal with medium and fine sand where sediment is additionally deposited by the Tamiraparani River. The mean values ranging from 1.69 to 2.01 φ with medium to fine sand. The fine sand in the riverine region indicates the depositional nature of the sediments. In pre-monsoon, the standard deviation ranges from 0.29 to 0.81 φ, which falls in the very well sorted to moderately well sorted. Estuary ranges from 0.63 to 1.30 φ, with moderately sorted, whereas in the marine sediments ranges from 0.4 to 1.01 φ, with moderately to moderately well- sorted and some patches of poorly sorted is observed. In both monsoons, the grain size variations are mostly influenced in river and offshore samples compared to the estuaries. The CM pattern indicates the deposition of sediments in graded suspension. In estuary, the sediments are medium sand with moderately to poorly sorted, fine skewed which are indicative of denudation processes taking place there. In marine, the sediments are medium-to-fine, moderately-to-well sorted, and fine skewed to very fine skewed sediments, probably as a result of the influence of palaeo-sediments deposited by rivers from inland as well as by waves and currents from offshore. Further, the marine samples also highlight depositional processes.     

Mafic magmas from Mount Baker in the northern Cascade arc,Washington: probes into mantle and crustal processes

Five mafic lava flows located on the southern flank of Mount Baker are among the most primitive in the volcanic field. A comprehensive dataset of whole rock and mineral chemistry reveals the diversity of these mafic lavas that come from distinct sources and have been variably affected by ascent through the crust. Disequilibrium textures present in all of the lavas indicate that crustal processes have affected the magmas. Despite this evidence, mantle source characteristics have been retained and three primitive endmember lava types are represented. These include (1) modified low-K tholeiitic basalt (LKOT-like), (2) typical calc-alkaline (CA) lavas, and (3) high-Mg basaltic andesite and andesite (HMBA and HMA). The Type 1 endmember, the basalt of Park Butte (49.3–50.3 wt% SiO₂, Mg# 64–65), has major element chemistry similar to LKOT found elsewhere in the Cascades. Park Butte also has the lowest overall abundances of trace elements (with the exception of the HREE), indicating it is either derived from the most depleted mantle source or has undergone the largest degree of partial melting. The Type 2 endmember is represented by the basalts of Lake Shannon (50.7–52.6 wt% SiO₂, Mg# 58–62) and Sulphur Creek (51.2–54.6 wt% SiO₂, Mg# 56–57). These two lavas are comparable to calc-alkaline rocks found in arcs worldwide and have similar trace element patterns; however, they differ from each other in abundances of REE, indicating variation in degree of partial melting or fractionation. The Type 3 endmember is represented by the HMBA of Tarn Plateau (51.8–54.0 wt% SiO₂, Mg# 68–70) and the HMA of Glacier Creek (58.3–58.7 wt% SiO₂, Mg# 63–64). The strongly depleted HREE nature of these Type 3 units and their decreasing Mg# with increasing SiO₂ suggests fractionation from a high-Mg basaltic parent derived from a source with residual garnet. Another basaltic andesite unit, Cathedral Crag (52.2–52.6 wt% SiO₂, Mg# 55–58), is an Mg-poor differentiate of the Type 3 endmember. The calc-alkaline lavas are least enriched in a subduction component (lowest H₂O, Sr/P_N, and Ba/Nb), the LKOT-like lavas are intermediate (moderate Sr/P_N and Ba/Nb), and the HMBA are most enriched (highest H₂O, Sr/P_N and Ba/Nb). The generation of the LKOT-like and calc-alkaline lavas can be successfully modeled by partial melting of a spinel lherzolite with variability in composition of slab flux and/or mantle source depletion. The HMBA lavas can be successfully modeled by partial melting of a garnet lherzolite with slab flux compositionally similar to the other lava types, or less likely by partial melting of a spinel lherzolite with a distinctly different, HREE-depleted slab flux.     

Synthesis in Estuarine and Coastal Ecological Research: What Is It,Why Is It Important,and How Do We Teach It?

During the last two decades, there has been growing interest in the integration of existing ideas and data to produce new synthetic models and hypotheses leading to discovery and advancement in estuarine and coastal science. This essay offers an integrated definition of what is meant by synthesis research and discusses its importance for exploiting the rapid expansion of information availability and for addressing increasingly complex environmental problems. Approaches and methods that have been used in published synthetic coastal research are explored and a list of essential steps is developed to provide a foundation for conducting synthetic research. Five categories of methods used widely in coastal synthesis studies are identified: (1) comparative cross-system analysis, (2) analysis of time series data, (3) balance of cross-boundary fluxes, (4) system-specific simulation modeling, and (5) general systems simulation modeling. In addition, diverse examples are used to illustrate how these methods have been applied in previous studies. We discuss the urgent need for developing curricula for classroom and experiential teaching of synthesis in coastal science to undergraduate and graduate students, and we consider the societal importance of synthetic research to support coastal resource management and policy development. Finally, we briefly discuss the crucial challenges for future growth and development of synthetic approaches to estuarine and coastal research.     

Detection of smectites in ppm and sub-ppm concentrations using dye molecule sensors

Methylene blue and rhodamine 6G were used as molecular sensors for the spectrophotometric titrations of the aqueous colloids of clay minerals (montmorillonite, illite and kaolinite). The dyes adsorbed on colloid particles form molecular aggregates, which exhibit spectral properties significantly different from those of dye solutions. Spectrophotometric titrations provide the most sensitive detection of smectites in aqueous colloids (sub-ppm concentrations); and the sensitivity further increases using second derivative spectroscopy. The endpoint of spectrophotometric titrations can be used for the determination of exchange capacity of the mineral in colloids and in this way to estimate its amount. The method is selective only to expandable clays, which was proven by experiments with kaolinite and illite. Spectrophotometric titrations have promising future in the analysis of clays and can be applied in many fields of geology, mineralogy, chemistry, material sciences or in industry. Its application may expand to the analysis of other nanomaterials built from charged particles and exhibiting metachromasy in the systems with organic dyes.     

Coupling hydrogeological with surface runoff model in a Poltva case study in Western Ukraine

This paper presents the hydrological coupling of the software framework OpenGeoSys (OGS) with the EPA Storm Water Management Model (SWMM). Conceptual models include the Saint Venant equation for river flow, the 2D Darcy equations for confined and unconfined groundwater flow, a two-way hydrological coupling flux in a compartment coupling approach (conductance concept), and Lagrangian particles for solute transport in the river course. A SWMM river–OGS aquifer inter-compartment coupling flux is examined for discharging groundwater in a systematic parameter sensitivity analysis. The parameter study involves a small perturbation (first-order) sensitivity analysis and is performed for a synthetic test example base-by-base through a comprehensive range of aquifer parametrizations. Through parametrization, the test cases enables to determine the leakance parameter for simulating streambed clogging and non-ocillatory river-aquifer water exchange rates with the sequential (partitioned) coupling scheme. The implementation is further tested with a hypothetical but realistic 1D river–2D aquifer model of the Poltva catchment, where discharging groundwater in the upland area affects the river–aquifer coupling fluxes downstream in the river course (propagating feedbacks). Groundwater contribution in the moving river water is numerically determined with Lagrangian particles. A numerical experiment demonstrates that the integrated river–aquifer model is a serviceable and realistic constituent in a complete compartment model of the Poltva catchment.     

A protoceratopsid skeleton with an associated track from the Upper Cretaceous of Mongolia

The Djadokhta Formation of the Gobi Desert is known for the number and diversity of dinosaur and other vertebrate bones and skeletons found there, but only theropod, hadrosaur and supposed ankylosaurid footprints have been reported from this stratum. Dinosaur footprints are also noted from the Nemegt Formation, and occur as typical dinosaur track accumulations (tracksites). An articulated protoceratopsid skeleton - specimen ZPAL Mg D-II/3 - was collected by the Polish-Mongolian Expedition of 1965 from the Djadokhta Formation of Flaming Cliffs in Mongolia. Recently, the natural cast of a tetradactyl digitigrade footprint was found underneath the pelvic girdle while the skeleton and matrix were being prepared. This is possibly the first find of a dinosaur track in close association with an articulated skeleton. Although Protoceratops is an extremely common dinosaur in Mongolia, its footprints have never previously been reported from the Late Cretaceous of the Gobi Desert.     

Geology and vein tin mineralization in the Dadoushan deposit,Gejiu district,SW China

Vein-type tin mineralization in the Dadoushan deposit, Laochang ore field, Gejiu district, SW China, is predominantly hosted in Triassic carbonate rocks (Gejiu Formation) over cupolas of the unexposed Laochang equigranular granite intrusion. The most common vein mineral is tourmaline, accompanied by skarn minerals (garnet, diopside, epidote, phlogopite) and beryl. The main ore mineral is cassiterite, accompanied by minor chalcopyrite, pyrrhotite, and pyrite, as well as scheelite. The tin ore grade varies with depth, with the highest grades (~1.2 % Sn) prevalent in the lower part of the vein zone. Muscovite ⁴⁰Ar–³⁹Ar dating yielded a plateau age of 82.7 ± 0.7 Ma which defines the age of the vein-type mineralization. Measured sulfur isotope compositions (δ ³⁴S = −4.1 to 3.9 ‰) of the sulfides (arsenopyrite, chalcopyrite, pyrite, and pyrrhotite) indicate that the sulfur in veins is mainly derived from a magmatic source. The sulfur isotope values of the ores are consistent with those from the underlying granite (Laochang equigranular granite, −3.7 to 0.1 ‰) but are different from the carbonate wall rocks of the Gejiu Formation (7.1 to 11.1 ‰). The calculated and measured oxygen and hydrogen isotope compositions of the ore-forming fluids (δ ¹⁸O_H2O = −2.4 to 5.5 ‰, δD = −86 to −77 ‰) suggest an initially magmatic fluid which gradually evolved towards meteoric water during tin mineralization.     

Evaluation of the water resource reproducible ability on Tarim River Basin in south of Xinjiang,northwest China

With the over-exploitation of water resources, water pollution and poor management of water infrastructures are exacerbated. Ecosystem degradation is apparent at the basin level. The Tarim River Basin in northwest China has seen intensive confrontation between environmental protection and economic development over the past five decades. Ambitious agricultural development and land reclamation projects implemented by the Chinese government in the early 1960s led to several influences. For example, the construction of dams like the Daxihaizi Reservoir disrupted the stream-flow to the lower reaches. Water resource reproducible ability (WRRA) refers to the ability of water resources to be continually added by the natural water cycle. It includes the supplementation of water quantity and the self-purification of water quality in the natural cycle of water resources. This study discusses the WRRA index and introduces the computational method for calculating the WRRA index for the Tarim River Basin. The following conclusions are observed: (1) from 1956 to 2005, the indices of WRRA in the Hotan River Basin, Yarkand and Aksu River Basin are 0.26, 0.55, 0.58, respectively, which are between 0 and 1. The results indicate that the hydrological cycle in these three sub-basins is in a reproducible state. (2) The WRRA index in the Kaidu-Kong River Basin is 1.23 > 1, which indicates that floods may occur in the Kaidu-Kong River Basin. (3) The index of WRRA in the main stream is 0, which indicates that the WRRA is very weak at this location, and zero-flow may occur. Calculating the WRRA of a basin can provide a basis for corresponding basin water resources management.