Review of factors affecting the distribution and abundance of waterfowl in shallow-water habitats of Chesapeake Bay

Long-term trends of waterfowl populations in Chesapeake Bay demonstrate the importance of shallow-water habitats for waterfowl species. Although recent increases in field feeding by geese and swans lessened the importance of shallow-water areas for these species, most duck species depend almost exclusively on shallow-water habitats. Many factors influenced the distribution and abundance of waterfowl in shallow-water habitats. Habitat degradation resulted in the decline in numbers of most duck species and a change in distribution of some species. Increased numbers of mallards (Anas platyrhynchos) in recent decades probably resulted from release programs conducted by the Maryland Department of Natural Resources and private individuals. Studies of food habits since 1885 showed a decline in submerged-aquatic vegetation in the diet of some species, such as the canvasback (Aythya valisineria), and an increase in the proportions of invertebrates in the diet. Diversity of food organisms for many waterfowl species has declined. Surveys of vegetation and invertebrates in the Chesapeake Bay generally reflect a degradation of shallow-water habitat. Human population increases in the Chesapeake Bay watershed directly and indirectly affected waterfowl distribution and abundance. The increase of exotic plant and invertebrate species in the bay, in most cases, benefited waterfowl populations. Increased contaminants have reduced the quality and quantity of habitat, although serious attempts to reverse this trend are underway. The use of shallow-water habitats by humans for fishing, hunting, boating, and other recreational and commercial uses reduced the use of shallow-water habitats by waterfowl. Humans can lessen the adverse influences on the valuable shallow-water habitats by restricting human population growth near these habitats and improving the water quality of the bay tributaries. Other affirmative actions that will improve these areas for waterfowl include greater restrictions on boat traffic in shallow-water habitats and establishing more sanctuaries in shallow-water areas that have complete protection from human disturbance. *** DIRECT SUPPORT *** A01BY074 00013     

Investigation of bacterial hopanoid inputs to soils from Western Canada

Hopanoids have been widely used as characteristic biomarkers to study inputs of bacterial biomass to sediments because they are preserved in the geologic record. A limited number of studies have been performed on hopanoid biomarkers in soils. The present study examined the distribution and potential preservation of hopanoids in soils that are developed under different climatic conditions and varying vegetative inputs. Solvent extraction and sequential chemical degradation methods were employed to extract both “free” and “bound” hopanoids, from three grassland soils, a grassland–forest transition soil, and a forest soil from Western Canada. Identification and quantification of hopanoids in the soil samples were carried out by gas chromatography–mass spectrometry. Methylbishomohopanol, bishomohopanol and bishomohopanoic acid were detected in all solvent extracts. The base hydrolysis and ruthenium tetroxide extracts contained only bishomohopanoic acid at a concentration range of 0.8–8.8 μg/gC and 2.2–28.3 μg/gC, respectively. The acid hydrolysis procedure did not release detectable amounts of hopanoids. The solvent extraction yielded the greatest amounts of “free” hopanoids in two of the grassland soils (Dark Brown and Black Chernozems) and in the forest soil (Gray Luvisol). In contrast, the chemical degradation methods resulted in higher amounts of “bound” hopanoids in the third grassland soil (Brown Chernozem) and the transition soil (Dark Gray Chernozem), indicating that more hopanoids exist in the “bound” form in these soils. Overall, the forest and the transition soils contained more hopanoids than the grassland soils. This is hypothesized to be due to the greater degradation of hopanoids in the grassland soils and or sorption to clay minerals, as compared to the forest and transition soils.     

Predicting metal detector performance for landmine clearance: soil magnetic map of Angola

A map depicting predicted classes of soil magnetic susceptibility in Angola was produced. The map is based on a classification system for the susceptibility of tropical soils set up by the authors and a 1:2,000,000 scale FAO soil map. Statistical data of two large groups of parent rock—ultrabasic, basic and intermediate igneous rocks on the one hand and acid igneous rocks and some slightly metamorphosed rocks and clastic sediments on the other—had been linked to three associated degrees of weathering. These determining factors were used to classify Angolan soils, and the overall method is semi-quantitative. The resulting map shows that easily available pedological information as given by FAO soil maps is generally appropriate to predict soil magnetic susceptibility. Potential metal detector performance failures may be predicted. The resulting information is a useful tool for planning the use of appropriate techniques in landmine clearance operations.     

Micromorphological interpretation of a “turf-filled” funerary shaft at St. Albans,United Kingdom

Seven thin sections and polished impregnated soil blocks from a (c. A.D. 55) “turf-filled” funerary shaft were analyzed employing soil micromorphology, energy dispersive X-ray analysis (EDXRA), microprobe analysis, and diatom investigations. As expected, soils from the local area had been exploited. In addition, it seems likely that the “turf” material included cattle dung, trampled soils, and enigmatic pondlike sediments. These findings, gained through exploiting the full potential of soil micromorphology and which are in full accord with other environmental data from the site, suggest that both natural local soils and soils associated with pasture and animal enclosures/husbandry were employed in the construction. © 1998 John Wiley & Sons, Inc.     

Dependence of waterbirds and shorebirds on shallow-water habitats in the Mid-Atlantic coastal region: An ecological profile and management recommendations

Waterbirds (waterfowl, colonially nesting wading and seabirds, ospreys [Pandion haliaetus], and bald eagles [Haliaeetus leucocephalus]) and shorebirds (sandpipers, plovers, and relatives) may constitute a large fraction of the toplevel carnivore trophic component in many shallow-water areas of the mid-Atlantic region. The large biomass of many species (>1 kg body mass for the two raptors and some waterfowl) and enormous populations (e.g.,>1 million shorebirds in late May in parts of Delaware Bay) reveal the importance of waterbirds as consumers and as linkages in nutrient flux in many shallow-water habitats. Salt and brackish marsh shallow-water habitats, including marsh pannes and tidal pools and creeks as well as constructed impoundments, are used intensively during most months of the year; in fall and winter, mostly by dabbling ducks, in spring and summer by migrant shorebirds and breeding colonial wading birds and seabirds. In adjacent estuaries, the intertidal flats and littoral zones of shallow embayments are heavily used by shorebirds, raptors, and colonial waterbirds in the May to September periods, with use by duck and geese heaviest from October to March. With the regional degradation of estuarine habitats and population declines of many species of waterbirds in the past 20 yr, some management recommedations relevant to shallow waters include: better protection, enhancement, and creation of small bay islands (small and isolated to preclude most mammalian predators) for nesting and brooding birds, especially colonial species; establishment of sanctuaries from human disturbance (e.g., boating, hunting) both in open water (waterfowl) and on land; better allocation of sandy dredged materials to augment islands or stabilize eroding islands; improvement in water management of existing impoundments to ensure good feeding, resting, and nesting opportunities for all the waterbirds; support for policies to preclude point and nonpoint source runoff of chemicals and nutrients to enable submerged aquatic vegetation to recover in many coastal bays; and improvement in environmental education concerning disturbance to wildlife for boaters and recreationists using the coastal zone. *** DIRECT SUPPORT *** A01BY074 00007     

Some applications of paleoecology to the management of tidal marshes

The shallow-water habitat is under increasing environmental pressures from accelerated sea-level rise and continual urban sprawl and will require well-informed management decisions to maintain its health into the future. One of the keys to the effective management of the shallow-water habitat is understanding the processes responsible for its development. Paleoecology has the potential to provide much insight into the development of the system, particularly when the impacts of accelerated sea-level rise on vegetation and sedimentation dynamics in tidal marshes is being considered. For example, a paleoecological comparison of tidal salt marshes to tidal freshwater marshes shows that rates of development will dictate the system's response to accelerated sea-level rise, with tidal freshwater marshes capable of transgressing landward more rapidly than their saline counterparts. Such information implies that management of the adjacent uplands is as important to the future of the system as management of the marsh itself. Therefore, it is important to consult paleoecological research when management strategies are being considered. *** DIRECT SUPPORT *** A01BY074 00010     

Heavy metal distribution in the surface layer of bottom sediments of the Kara Sea

This paper addresses the distribution of heavy metals (Co, Ni, Cu, Zn, Cd, Sn, Sb, Pb, and Bi) as well as Si, Al, Fe, and Mn in the surface (0–2 cm) layer of bottom sediments of the Kara Sea. The contents of these elements are determined in each of the previously distinguished facies-genetic types of terrigenous sediments: fluvial, glacial, estuarine, shallow water–marine, “background” marine, and relict sediments. It is shown that these types reflect the modern conditions of accumulation of river discharge material, which forms fans of two greatest Siberian rivers, Ob and Yenisei. The main stages are distinguished in heavy metal accumulation. The first stage is related to the avalanche sedimentation of terrigenous sediments in the estuary and characterized by the elevated contents of Co, Ni, Cu, Zn, Cd, Sb, and Bi. The second stage reflects the mechanical differentiation of sedimentary material by waves and bottom currents in a shallow-water sea part adjacent to the estuarine zone, with accumulation of Pb- and Sn-bearing “heavy” ore minerals. The deepwater background terrigenous–marine sediments accumulate mainly Ni, Zn, and Cd, as well as Mn. The relict sediments differ in the high contents of Si, Mn, and Sn.     

Toward new paradigms in coastal resource management: Linkages and institutional effectiveness

Explosive population growth is expected to continue in coastal regions, and growth rates many times the national average are expected in many coastal counties in the next two decades. Most shallow-water marine habitats now exhibit “stress” from human activities and linkages between adverse environmental impacts and coastal development are apparent. These linkages are complex, often not well understood, yet are expected to increase in strength as coastal populations expand. Sound science-based management strategies are essential if we are to preclude continued deterioration of coastal environments. Environmental management is a politically mediated activity, however, and a broad array of organizations, both public and private, collectively determine societal response to management decisions. While our current regulatory infrastructure has an examplary record of achievement in environmental protection, the fact remains that adverse impacts to shallow-water marine habitats continue at significant rates. Both lack of scientific information and structural problems in our current institutional infrastructure are identified as impediments to better management performance for coastal habitats. Seven structural impediments to efficient science-based management in our current institutional infrastructure are identified. The issues are complex and comprehensive reform is politically difficult. Nonetheless, the magnitude, geographic scale, and temporal urgency of anticipated impacts from future growth and development scenarios argues strongly for the implementation of sound practical solutions to environmental protection on a sustained basis. Factors affecting management performance will also be amplified in an environment of limited investment in research and management infrastructure. Among the central themes are that science-based management practices in the future will require holistic approaches in which environment and economic development are inseparable. To work effectively large-scale, regional management schemes must build political consensus and integrate knowledge at unprecedented rates. Processes that increase rates of dissemination of scientific information into the public policy arena can significantly enhance management performance. Serious doubts are raised as to whether the current regulatory infrastructure can adequately respond to the complexicty, scale, and urgency future coastal management will demand. While comprehensive institutional reform will be difficult, a number of ideas are advanced in the context of improving institutional performance to a level necessary for large-scale, sustained management of coastal ecosystems.     

Comparing impacts to shallow-water habitas through time and space

Impacts to shallow-water estuarine habitats should be assessed in a holistic context reflecting both the interrelatedness of habitats that characterize these environments and the history of impacts, human and natural, that have shaped their present ecology. In a holistic context these habitats are considered to be dynamic associations of macrohabitats and micro-habitats, interacting through time to affect the quantity (Q₁), quality (Q₂), and timing (T) of material and energy transfer within the system. Where data are available, this holistic approach (Q₁, Q₂ and T or Q₂T) allows impacts to be evaluated in a multidimensional framework of time and space. Unfortunately, few data are available to evaluate the long-term implications of timing, the T factor. Recorded observations of most estuarine systems cover tens of years, periods not extensive enough to assess long-term changes to the environment or to distinguish man's impacts from those of nature. Sustained droughts, for example, can cause massive disruption in estuaries, altering habitats and species composition. When these changes occur over periods of 5–10 yr, the changes are difficult to identify and may be attributed to man's activities rather than nature's Using the Hudson River estuary as an example, we have knowledge of historical impacts extending back to the 1700s, ranging from dredging to major droughts. For the Hudson River, recorded observations of rainfall and river flow extend back about 70 yr; however, tree rings provide a more extensive record since tree growth increments are directly dependent upon rainfall. The Hudson River drought record was extended back to 1694 using tree rings. Using the reconstructed record, the relationship between today's conditions—flow and average location of the ocean-derived salt front—can be placed in a historical context. This historical perspective allows us to place present-day human impacts into the contex of long-term natural impacts and to discriminate among these effects. The drought example is particularly relevant to shallow-water habitats because these habitats provide an interface between fresh and marine waters. *** DIRECT SUPPORT *** A01BY074 00008     

湖泊三角洲沉积露头精细解剖——以鄂尔多斯盆地裴庄剖面为例

客观、精细刻画储集体内部结构已成为油气精细勘探开发的必然要求.沉积露头为地下储层地质模型的建立发挥着不可替代的作用.以鄂尔多斯盆地裴庄剖面延安组为例,采用沉积学和构型要素的分析方法,详细剖析了湖泊三角洲水下沉积的内部结构.研究表明,裴庄剖面发育9种岩相类型,3类岩相组合,进而可识别出前三角洲、席状砂、远砂坝、河口坝、水下分流河道、水下分流间湾等6类沉积结构单元.在水下分流河道中可识别出5级界面.研究认为,浅水三角洲前缘的砂体并非仅有水下分流河道,还有河口坝、远砂坝以及席状砂等多种类型.裴庄剖面总体为一套向上变粗的沉积序列,三角洲前缘的前积结构表现不明显.加强露头研究并开展针对性的物理模拟实验,是解答浅水三角洲研究争论的重要途径.     

Fossilization of organic matter,formation of oil and gas,and emigration of hydrocarbons in carbonate rocks

Based on the comparison of conditions of organic matter (OM) accumulation in modern carbonate sediments in Paleozoic shallow-water carbonate sediments, it is shown that drastic disproportion in the degree of preservation of the primary dispersed OM (DOM) in the clayey and “pure” varieties of carbonate rocks is not caused by its loss due to the diagenetic oxidation in the shallow-water setting, its disintegration due to the vital activity of microorganisms, or due to its consumption for the reductive oxide forms of Fe. It has experimentally been proven that a great significance in oil and gas formation in carbonate rocks belongs to OM, which occurs in the carbonate component of the chloroform bitumen (CB_CCR) and is not determined by the conventional analytical methods (e.g., incineration of the HCl-insoluble rock remnant). Higher concentration of hydrocarbons (HC) in CB_CCR relative to CBA is confirmed by the oil-generating properties of “pure” carbonate rocks. The release and emigration of HC from carbonate rocks are promoted by their secondary transformations.     

Colluviation and soil formation as geoindicators to study long-term environmental changes

Soil is a dynamic natural body and fundamental resource. Human activities influence intensively the natural processes in soils. They modify and accelerate the development of soils. In this investigation, the deposition of colluvial sediments (colluviation) and soil formation are proposed as geoindicators for a better understanding of long-term environmental changes and environmental impact assessment. Deposition of colluvial sediments during several time periods and subsequent soil formation under different land-use systems reflect important aspects on the long-term human interference in the environment. In this study, we hypothesize that intensive human activities and environmental changes during middle and late Holocene are responsible for a strong modification of soils in an investigation area in Schleswig–Holstein (Germany). Soil age information together with geomorphological data, physical, chemical and biological soil properties provide the database which is necessary to study the types and rates of colluviation and soil formation. After the investigation with a high resolution in time and space, results show that middle and late Holocene land-use changes and land management are responsible for soil formation in colluvial layers. Properties of soils and sediments vary intensively from Mesolithic until Modern times. Intensive soil formation took place during periods of geomorphodynamic stability in dense woodland. Evidence in our investigations shows that colluviation has a strong relation with decision-making and environmental degradation in the past. This confirms, too, that a geoindicator concept is needed to understand and to monitor long-term environmental changes and degradation.     

热带土壤发育过程的定量研究—以海南岛北部为例

海南岛北部不同时期喷发的玄武岩上发育的土壤构成一个成土年代系列, 由此可以定量地探讨发育过程中土壤性质随风化成土年龄增加的变化规律.研究表明土体厚度、B层厚度、RR指数、w(REE)、w(Ba)/w(Nb)、w(Fe_d)/w(Fe_t)、w(Fe_d)、w(Fe_o)/w(Fe_d)、土壤硅铝率、土壤硅铁铝率、频率磁化率等土壤性质与风化成土年龄具有确定的相应关系.根据土壤发生学原则, 得出土壤性质与风化成土年龄两者间的统计方程.对于成土环境相同或相近地区可从这些方程由土壤性质推断相对风化成土年龄和发育程度, 也可由风化成土年龄估计土壤特性, 研究成土速率      

Human impacts on soils: Tipping points and knowledge gaps

Soil ecosystem functions are derived from plant, animal and microorganism communities and the non-living environment interacting as a unit. Human activities have affected soil ecosystem functions and in many cases caused soil ecosystem collapse. This review provides a synthesis of current knowledge of human impacts on soil ecosystems, with a special focus on knowledge gaps regarding soil ecosystem shifts and tipping points, using the island of Crete, Greece as an example. Soil ecosystem shifts are abrupt changes that occur at “tipping points” and have long-lasting effects on the landscape and both the biotic and abiotic structure of the soil. These shifts can occur due to climate change, land use change, fertilization, or above-ground biodiversity decline. The environmental pressures in the agricultural land of Crete, place the island very close to tipping points, and make it an “ideal” area for soil ecosystem shifts. Reversing the trend of the shift while using the soil ecosystem services, means that significantly more organic matter needs to be added to the soil compared to the amount added under set-aside conditions. Potential nutrient supply and demand calculations indicate that fertilizer demand in Crete can be satisfied by recycling of bio-residue and livestock excreta produced on the island. Soil fertility improves faster if, in addition to bio-fertilization, farmers use traditional agricultural practices such as crop rotations and legume row plantings within olive trees and orchards. A renewed soil fertility paradigm shift requires a “holistic” management of biotic-soil–water resources in order to provide sufficient and an appropriate type of organic matter to the plant–microorganism system to maximize food production.     

Occurrence of triterpenyl acetates in soil and their potential as chemotaxonomical markers of Asteraceae

As a part of a wider study aimed at determining new molecular biomarkers in soils and sediments that could be specific for distinct vegetation types with respect to unravelling past changes in land use, we analysed the neutral lipid content of soil developed in the catchment of a small lake in central France. The ketone/acetate lipid fraction of soil under pasture or meadow contained a series of pentacyclic triterpenyl acetates with wide structural diversity, most being reported in soil for the first time. The restricted number of potential plant sources of triterpenyl acetates (some produced by a single species) underlines the potential of triterpenyl acetates as new biomarkers to track past vegetation change in palaeoenvironmental studies, when found in natural archives such as soil, sediments or peat.     

Magnetic studies applied to different environments (soils and stream sediments) from a relatively polluted area in Buenos Aires Province,Argentina

Anthropogenic influence, mainly due to urban and industrial activities, may affect fluvial environments and soils, via atmospheric contamination and liquid and solid waste.Continuing previous works on stream sediments and soils, the Gran La Plata area was chosen. In this area, located in the Northeast of Buenos Aires Province (Argentina), several streams and soils were sampled. The streams have similar characteristics, although some of them have a higher input of pollutants (fluvial effluents, fly ashes, solid wastes, etc.). The studied soils have different pedological development.Magnetic and chemical studies were carried out in the laboratory. Analyses of the results indicated that the behavior of magnetic parameters can be related to the variations of heavy metal contents in stream sediments but there is not a good correlation in soils. The comparison between both environments (stream-sediment and soils) reveals a different impact of pollutants. Magnetite, especially PSD grains, seems to be the main carrier for both environments.     

层状土毛细水上升过程中Lucas-Washburn模型评价及修正

受界面效应影响,毛细水在层状土中运移规律还难以用描述均质土中水分运移规律的Lucas-Washburn（LW）渗吸模型进行描述。基于此,本文设计了层状土室内模型试验,采用分布式的主动加热光纤法（简称AHFO）监测毛细水上升过程。根据AHFO测试结果,进一步对LW模型进行了修正,提出了适用于描述层状土中毛细水上升规律的ILW模型,并对ILW模型进行了试验验证。试验结果表明:（1）当毛细水湿润锋抵达“黏土（下部）-砂土（上部）”界面时,会产生“毛细屏障作用”,从而导致上部砂土中毛细水含水率急剧下降;（2）“毛细屏障作用”由砂土和黏土中的基质吸力不均衡造成,基质吸力大小由含水率决定;（3）当毛细水湿润锋抵达“砂土（下部）-黏土（上部）”界面时,在界面处出现“反毛细屏障作用”,从而导致上部黏土层中的含水率比相邻下部砂土层含水率更高;（4）虽然常见的LW模型可准确预测均质土中毛细水上升高度及速率,但受“毛细屏障作用”和“反毛细屏障作用”影响,LW模型在层状土中失效;（5）相比LW模型,ILW模型精度更高,能够更加准确地描述层状土中毛细水上升规律。     

松辽盆地王府凹陷泉三、四段浅水三角洲沉积特征及模式

在岩心观察的基础上,结合测井、地震和区域背景资料分析,认为王府凹陷泉三、四段沉积时期普遍发育浅水三角洲沉积。由于受地形、古气候和水动力条件等多重因素的影响,研究区发育的浅水三角洲在沉积构造、沉积序列、微相类型、三角洲内部结构以及地球物理响应特征等方面呈现出与经典三角洲不同的沉积特征:具有建设性三角洲沉积特征,平面上呈网状,前缘相带延伸较远。具有相对发育的水下分流河道,河口砂坝欠发育;垂向上发育多次间断正韵律。紫红色泥岩大面积展布,生物扰动强烈。砂岩中发育强水动力浅水沉积构造,Gilbert型三角洲的3层结构不明显。浅水三角洲识别出两个亚相和7个微相。研究区具有良好的生储盖配置关系,利于岩性油气藏的形成,其中水下分流河道和分流河道砂体储层物性好,为最有利储层。     

Correlation of magnetic and lithologic features of soils and Quaternary sediments from the Undulating Pampa,Argentina

A lithological and mineral magnetic study of three soil and underlying sedimentary sections located at different topographic positions in the Undulating Pampa was performed. On the basis of grain size analyses, clay, silt and sand mineralogy, and total Ti/Zr relationship three different sedimentary units were recognised in the profiles under study suggesting that the area has been influenced by three different sources of sediments. Magnetic susceptibility (MS) appears to be related to lithology, allowing the identification of some material and lithologic discontinuities. In the studied cases the maximum values of MS appear in both the B horizons of the present zonal soils as well as in the primary or reworked loess levels. In contrast, minimum values are associated with calcrete, paleosol, and hydromorphic horizons. Although magnetic susceptibility appears to be an effective means for identifying different materials and pedological features in this area, due to the superposition of effects on the magnetic signal a thorough interpretation of MS requires that a composite analysis should be made.     

Differentiating temperate tree species and their organs using lipid biomarkers in leaves,roots and soil

Although fatty acids and alcohols in plant polyesters can be useful indicators of organic matter provenance in soils and sediments, interpretation is limited by uncertainty in: (i) the distribution of lipids among plant species and their organs (e.g. leaves and roots) and (ii) the extent to which plant lipid composition is recorded in soils and sediments. In this study, we compare lipids in leaves, roots and soils from 11 temperate tree species. Base hydrolysis was used to release ester-bound lipids and solvent extraction was then used to recover both hydrolysable and “free” lipids. Leaf and root lipid composition varied substantially among the tree species and we highlight differences among evergreen conifers, deciduous broadleaved angiosperms and a deciduous conifer (Larix decidua). Some of the variation appears to be linked to the morphology and lifespan of leaves and roots. Soils preserved much of the variation in the leaf and root lipid composition of the overlying tree species. Yet, the concentration of some lipids in soil diverged from their concentration in tree leaves and roots, reflecting an undocumented input from understory plants and other plant organs (e.g. seeds) or variation in the extent of lipid preservation in soil. Finally, by comparing leaf and root lipid composition, our results help constrain the attribution of lipids to each of these plant organs. This allowed us to evaluate the utility of leaf-derived lipids as plant type biomarkers and to document a substantial contribution of root-derived lipids to soil beneath all 11 tree species.