Water and Boating Activity as Dispersal Vectors for <Emphasis Type="Italic">Schinus terebinthifolius</Emphasis> (Brazilian pepper) Seeds in Freshwater and Estuarine Habitats

Schinus terebinthifolius (Brazilian pepper), a native of South America, is currently naturalized in 20 countries worldwide and can alter native systems by displacing flora and forming monotypic stands. The primary described mechanism of seed dispersal is through consumption of fruits by birds and mammals. We evaluated an alternative dispersal method by evaluating the potential for S. terebinthifolius growing in freshwater and estuarine environments to disperse via water currents. Specifically, we: (1) determined the duration fruits remained buoyant in three salinities, (2) estimated the viability of seeds after 7 days in water, (3) estimated the dispersal rate of floating solitary fruits, and (4) examined the role of boat wakes in moving seeds above mean high water at the shoreline. The length of time fruits floated in 0 ppt water (4.9 days) was significantly less than 15 ppt saltwater (6.2 days), and 30 ppt saltwater (6.9 days). After 7 days, over 13% of seeds remained viable in 0 ppt, 15 ppt, and 30 ppt water. By combining mean dispersal rates and the mean number of days fruits floated, we calculated individual fruits could be transported 16.9 km in 0 ppt and over 22 km in 15 and 30 ppt water. To increase germination, seeds must be stranded above the intertidal zone. Wind wakes alone never achieved this result; however, boat wakes plus wind wakes significantly increased the movement of fruits above the intertidal region into drier soils. The use of both vertebrate dispersal vectors and water dispersal may potentially increase the rate of invasion, establishment, and survival of S. terebinthifolius in freshwater and estuarine environments.     

Long-Term Changes in Water Quality and Productivity in the Patuxent River Estuary: 1985 to 2003

We conducted a quantitative assessment of estuarine ecosystem responses to reduced phosphorus and nitrogen loading from sewage treatment facilities and to variability in freshwater flow and nonpoint nutrient inputs to the Patuxent River estuary. We analyzed a 19-year dataset of water quality conditions, nutrient loading, and climatic forcing for three estuarine regions and also computed monthly rates of net production of dissolved O₂ and physical transport of dissolved inorganic nitrogen (DIN) and phosphorus (DIP) using a salt- and water-balance model. Point-source loading of DIN and DIP to the estuary declined by 40–60% following upgrades to sewage treatment plants and correlated with parallel decreases in DIN and DIP concentrations throughout the Patuxent. Reduced point-source nutrient loading and concentration resulted in declines in phytoplankton chlorophyll-a (chl-a) and light-saturated carbon fixation, as well as in bottom-layer O₂ consumption for upper regions of the estuary. Despite significant reductions in seaward N transport from the middle to lower estuary, chl-a, turbidity, and surface-layer net O₂ production increased in the lower estuary, especially during summer. This degradation of water quality in the lower estuary appears to be linked to a trend of increasing net inputs of DIN into the estuary from Chesapeake Bay and to above-average river flow during the mid-1990s. In addition, increased abundance of Mnemiopsis leidyi significantly reduced copepod abundance during summer from 1990 to 2002, which favored increases in chl-a and allowed a shift in total N partitioning from DIN to particulate organic nitrogen. These analyses illustrate (1) the value of long-term monitoring data, (2) the need for regional scale nutrient management that includes integrated estuarine systems, and (3) the potential water quality impacts of altered coastal food webs.     

Slope inclinometers for landslides

Slope inclinometers/indicators are used to determine the magnitude, rate, direction, depth, and type of landslide movement. This information is usually vitally important for understanding the cause, behavior, and remediation of a landslide. However, many inclinometer measurements fail to achieve these intended aims because of lack of appreciation of the many factors that need to be correctly implemented during installation, monitoring, and data reduction to yield useful data. This paper presents some guidelines for understanding, installing, and interpreting slope inclinometers and presents three case histories that illustrate some of the pitfalls that can develop if these guidelines are not followed.     

An implementation of rock engineering system for ranking the instability potential of natural slopes in Greek territory. An application in Karditsa County

This paper presents an application of rock engineering system (RES) in an attempt to reveal and assess the inherent instability potential of 388 sites where equivalent landslides have been manifested and recorded in the region of Karditsa County, Greece. The main objective has been defining the principal causative and triggering factors responsible for the manifestation of landslide phenomena, quantify their interactions, obtain their weighted coefficients, and calculate the instability index, which refers to the inherent potential instability of each natural slope of the examined region. From the statistical interpretation of the data reported in a well-documented database and concerning the examined failure sites, a clear correlation between the instability index and the area affected by a single landslide event has been revealed. Almost the entire failure sites, 98% of the examined slope sites, exhibit an instability index value over 55, a value which is thought to be a critical threshold for landslide manifestation concerning natural slopes in Karditsa County. It is argued that the presented RES methodology, engaging the selected set of parameters, could be considered as an effective expert's tool for ranking, in an objectively optimal and simple way, the instability potential of natural slopes in Karditsa County, and thus providing a tool for sound zoning landslide hazard.     

印度板块和亚洲大陆在何时何地碰撞

印度板块和亚洲大陆的初始碰撞时间是所有相关的喜马拉雅-西藏造山体系演化模式的主控条件,并严重影响到对众多与青藏高原隆升和东亚大陆挤出相关的地质过程速率的解释,以及对新生代全球气候变化的理解。尽管印度板块和亚洲大陆汇聚的速率在55Ma突然减缓被广泛地认为是初始碰撞的标志,但这次碰撞所造成的主要构造效应直到20多个百万年以后才显现出来。对印度板块和亚洲大陆相对位置的重新估算,表明它们在55Ma时并没有达到可以彼此发生碰撞的距离。基于来自西藏新的野外证据和对已有数据的重新评估,认为初始碰撞发生在始新世—渐新世之交（约34Ma）,并对55Ma时发生的地质事件提出了另一种解释     

甘肃庆城庄19井区上三叠统延长组长82亚油层组 低渗透储层的地质特征

长82亚油层组是甘肃庆城地区庄19井区上三叠统延长组中储集砂岩相对富集的层位,但砂岩低渗透性的特点显著,成为影响该区石油储产量增长的主要地质因素.结合前人的相关工作,通过钻井岩心观察、测井曲线分析、储层岩石实验测试等工作,详细地分析了庄19井区长82亚油层组低渗透储层的地质特征,认为沉积微相和压实作用、胶结作用是控制低渗透性储集砂岩发育和分布的主要地质因素,寻找以水下分流河道微相为代表的有利储集相带砂岩体是油气勘探的重要方向.     

Automated Image Registration for Hydrologic Change Detection in the Lake-Rich Arctic

Multitemporal remote sensing provides a unique tool to track lake dynamics at the pan-Arctic scale but requires precise registration of thousands of satellite images. This is a challenging task owing to a dearth of stable features to be used as tie points [(TPs), i.e., control points] in the dynamic landscapes. This letter develops an automated method to precisely register images in the lake-rich Arctic. The core premise of the method is that the centers of lakes are generally stable even if their shorelines are not. The proposed procedures first extract lakes in multitemporal satellite images, derive lake centroids and match them between images, and then use the centroids of stable lakes as TPs for image registration. The results show that this approach can achieve subpixel registration accuracy, outcompeting the conventional manual methods in both efficiency and accuracy. The proposed method is fully automated and represents a feasible way to register images for lake change detection at the pan-Arctic scale.      

First finds of Late Tithonian and middle-late Albian radiolarian assemblages in volcanogenic-siliceous rocks of the Amur River right lower reaches and their tectonic significance

The lithological-stratigraphic study of volcanogenic-siliceous rocks developed on the left side of the Machtovaya River, a right tributary of the Amur River, yielded the first radiolarian assemblages of the late Late Tithonian, the late Late Tithonian-early Valanginian, and the middle-late Albian age. It is established that the stratigraphic succession of volcanogenic-siliceous rocks in this area is composed of upper Tithonian-Valanginian dark red to red-brown cherts with basalts in the lower part of the section and Albian dark gray clayey cherts, olive-gray siliceous-tuffaceous argillites, and tufaceous siltstones in its upper part. The replacement of cherts by their clayey varieties likely occurred in the Aptian. The composition, structure, and age of these strata and the rocks constituting the Kiselevka-Manoma accretionary complex are different, which indicates their different tectonic origin.     

Geochemistry of magmatic rocks of the Koksharovka alkaline-ultrabasic massif,primorye, and results of trace-element modeling

New geochemical data are presented on the magmatic rocks of the Late Jurassic Koksharovka alkaline-ultrabasic massif, which is associated with deposits of vermiculite, apatite, V-bearing titanomagnetite, and placer isoferroplatinum. The REE geochemistry and strontium, oxygen, and carbon isotopic composition of carbonatites and related ijolites and pyroxenites, together with geological observations, point to the magmatic origin of the Koksharovka carbonatites. The origin of associated magmatic rocks is discussed. Trace element modeling of partial melting of mantle sources was conducted to decipher the genesis of the melts of the Koksharovka carbonatites and host titanite-kaersutite pyroxenites.     

A new concept of pedogenic nodule formation in landscapes of the Russian Far East

The typification of ferromanganese nodules (FMN) formed in subaqueous and subaerial settings and in residual materials, as well as FMN localization in various sediments and soils, is discussed. The genetic diversity of morphologically similar FMN and the transformation of FMN-bearing complexes with changes in landscapes have been established.