Potential microbial bioinvasions via ships' ballast water, sediment, and biofilm   总被引：4，自引：0，他引：4  

Drake LA  Doblin MA  Dobbs FC 《Marine pollution bulletin》2007,55(7-9):333-341

A prominent vector of aquatic invasive species to coastal regions is the discharge of water, sediments, and biofilm from ships' ballast-water tanks. During eight years of studying ships arriving to the lower Chesapeake Bay, we developed an understanding of the mechanisms by which invasive microorganisms might arrive to the region via ships. Within a given ship, habitats included ballast water, unpumpable water and sediment (collectively known as residuals), and biofilms formed on internal surfaces of ballast-water tanks. We sampled 69 vessels arriving from foreign and domestic ports, largely from Western Europe, the Mediterranean region, and the US East and Gulf coasts. All habitats contained bacteria and viruses. By extrapolating the measured concentration of a microbial metric to the estimated volume of ballast water, biofilm, or residual sediment and water within an average vessel, we calculated the potential total number of microorganisms contained by each habitat, thus creating a hierarchy of risk of delivery. The estimated concentration of microorganisms was greatest in ballast water>sediment and water residuals>biofilms. From these results, it is clear microorganisms may be transported within ships in a variety of ways. Using temperature tolerance as a measure of survivability and the temperature difference between ballast-water samples and the water into which the ballast water was discharged, we estimated 56% of microorganisms could survive in the lower Bay. Extrapolated delivery and survival of microorganisms to the Port of Hampton Roads in lower Chesapeake Bay shows on the order of 10(20) microorganisms (6.8 x 10(19) viruses and 3.9 x 10(18) bacteria cells) are discharged annually to the region.  相似文献   

Modelling ecosystem functions and properties at different time and spatial scales in shallow coastal lagoons: An application of the LOICZ biogeochemical model     

Gianmarco Giordani  Martina Austoni  José M. Zaldívar  Dennis P. Swaney  Pierluigi Viaroli 《Estuarine, Coastal and Shelf Science》2008

The Land-Ocean Interactions in the Coastal Zone (LOICZ) biogeochemical model (LBM) was applied at different temporal and spatial scales in 17 Italian lagoons of the LaguNet network (http://www.dsa.unipr.it/lagunet). A series of alternative assumptions taking into account benthic vegetation and sedimentary fluxes were introduced and compared with the classical LBM approach at various time scales. The reliability of the LBM application to the seventeen Italian lagoons was tested by comparison to a pool of shallow coastal systems from the global LOICZ database with comparable depths and sizes. The nutrient loads of the Italian sites can be considered relatively low, particularly for dissolved inorganic phosphorus (DIP). Although the median values of estimated internal transformations (source-sink) of both dissolved inorganic phosphorous and nitrogen at the LaguNet sites were comparable with the selected LOICZ sites, the positive and negative extreme values were one order of magnitude lower. Overall, the LBM applications to the Italian sites gave good quality budgets for shallow systems subjected to relatively low nutrient inputs and with a wide range of primary producer communities, including seagrass, macroalgae and phytoplankton. Furthermore, stoichiometry of Carbon:Nitrogen:Phosphorous for the different primary producer groups allowed the integration of previous studies by identifying a series of relationships between nutrient loads and ecosystem functions.  相似文献   

Firms and sustainability: Mapping the intellectual origins and structure of the corporate sustainability field     

Martina K. Linnenluecke  Andrew Griffiths 《Global Environmental Change》2013,23(1):382-391

Business research has repeatedly been criticized for its lack of engagement with pressing issues such as climate change, despite a surge of publications on corporate sustainability topics in recent years. We are therefore interested in identifying the knowledge development and knowledge gaps in business scholarship on the relationship between firms, environment and society. This paper provides a systematic review of the corporate sustainability field in form of a bibliometric analysis based on citation data acquired from the Social Sciences Citation Index. The final dataset contained 3117 records published between 1953 and 2011. Our analysis shows that, over the last 50 years, the field of corporate sustainability has emerged from a few primary nodes of research and developed into four distinct conceptual genealogies: corporate social performance theory, stakeholder theory, a corporate social performance versus economic performance debate, and a greening of management debate. The results of our analysis suggest four key findings. First, the four genealogies only comprise a relatively narrowly focused research scope. Second, there is very little integration and citation of work in other disciplinary areas such as ecology or environmental science. Third, the existing literature has a strong focus on empirically examining the relationship between a firm's environmental and/or social performance and its financial performance. Finally, there is little consideration of managerial implications and consequences of climate change in the corporate sustainability literature to date. We suggest that while this may be a reflection of an insular field, it may also be a role played by the management literature turning away from problem based issues in favor of empirical results, theory building, and the identification of variables that influence firm profitability and can be subjected to direct managerial control. We conclude by outlining pathways for future research.  相似文献   

Collisional velocities and rates in resonant planetesimal belts     

Martina Queck  Alexander V. Krivov  Miodrag Sremčević  Philippe Thébault 《Celestial Mechanics and Dynamical Astronomy》2007,99(3):169-196

We consider a belt of small bodies (planetesimals, asteroids, dust particles) around a star, captured in one of the external or 1:1 mean-motion resonances with a massive perturber (protoplanet, planet). The objects in the belt collide with each other. Combining methods of celestial mechanics and statistical physics, we calculate mean collisional velocities and mean collisional rates, averaged over the belt. The results are compared to collisional velocities and rates in a similar, but non-resonant belt, as predicted by the particle-in-a-box method. It is found that the effect of the resonant lock on the velocities is rather small, while on the rates more substantial. At low to moderate eccentricities and libration amplitudes of tens of degrees, which are typical of many astrophysical applications, the collisional rates between objects in an external resonance are by about a factor of two higher than those in a similar belt of objects not locked in a resonance. For Trojans under the same conditions, the collisional rates may be enhanced by up to an order of magnitude. The collisional rates increase with the decreasing libration amplitude of the resonant argument, depend on the eccentricity distribution of objects, and vary from one resonance to another. Our results imply, in particular, shorter collisional lifetimes of resonant Kuiper belt objects in the solar system and higher efficiency of dust production by resonant planetesimals in debris disks around other stars.  相似文献   

Historical problems of travel for women geologists     

Cynthia V. Burek  & Martina Kölbl-Ebert 《Geology Today》2007,23(1):30-32

From unsuitable clothes to lack of chaperones, from harassment to lack of proper funding, throughout history women geologists have encountered difficulties travelling to their field locations or working in the field, whether these locations were close by or abroad. Most early female geologists were able to avoid many difficulties because they were protected through working locally, where their high social standing was known and respected, or because they worked in a team with husband, father or brother. However, the problem was to grow in the second half of the nineteenth century, when women started to appear as students and professionally trained geologists. This feature explores the difficulties of female geologists undertaking fieldwork from the late nineteenth to the mid-twentieth century.  相似文献   

Consequences of anthropogenic activity for two remote alpine lakes in NW Slovenia as tracked by sediment geochemistry     

Gregor Muri  Branko Čermelj  Radojko Jaćimović  Dragomir Skaberne  Andrej Šmuc  Martina Burnik Šturm  Janja Turšič  Polona Vreča 《Journal of Paleolimnology》2013,50(4):457-470

Several geological and geochemical parameters were determined in the sediments of the 5th (5 J) and 6th (6 J) Triglav Lakes, Julian Alps (NW Slovenia), in order to study the impact of natural catchment characteristics and anthropogenic activity. Fish were introduced into both lakes in 1991 and a mountain hut lies on the shore of 5 J. Sedimentary grain size (GS) was distinctly coarser in 5 J than 6 J, with arithmetic means ranging between 46 and 60 and 23–36 μm, respectively. In contrast, the mineralogical composition of the two sediments was similar. Calcite predominated strongly, comprising more than 77 % of total minerals, while dolomite and quartz were rare. Organic carbon (OC) and total nitrogen (TN) concentrations were highest in surficial sediments, with levels of 14.4 and 1.8 %, and 19.3 and 2.4 % observed in 5 J and 6 J, respectively. C/N ratios (atomic) were lowest in the same surface sediments, with the two lakes characterized by similar values (9.6 vs. 9.4, respectively), suggesting a predominance of autochthonous organic matter (OM) in both lakes. Contemporary δ¹³C values were lower in 5 J (?21.0 ‰) than 6 J (?18.5 ‰) sediments. Considerable changes in these four parameters were observed in recently deposited material, reflecting a shift in the trophic status of both lakes that was likely induced by the introduction of fish. In addition, the smaller and shallower 6 J seemed to respond to changes faster than the larger and deeper 5 J, indicating the higher sensitivity of the former. δ¹⁵N values in surface sediments of 5 J and 6 J were ?2.9 and ?4.4 ‰, respectively, with levels increasing gradually with depth to approximately +1.0 ‰ in deeper sediments. The observed changes could most likely be attributed to the atmospheric deposition of reactive nitrogen. The mountain hut has seemingly not had a significant enough impact on the lakes to be recorded in their sediments.  相似文献   

The Sitnikov problem for several primary bodies configurations     

Gastón Beltritti  Fernando Mazzone  Martina Oviedo 《Celestial Mechanics and Dynamical Astronomy》2018,130(7):45

In this paper we address an \(n+1\)-body gravitational problem governed by the Newton’s laws, where n primary bodies orbit on a plane \(\varPi \) and an additional massless particle moves on the perpendicular line to \(\varPi \) passing through the center of mass of the primary bodies. We find a condition for the described configuration to be possible. In the case when the primaries are in a rigid motion, we classify all the motions of the massless particle. We study the situation when the massless particle has a periodic motion with the same minimal period as the primary bodies. We show that this fact is related to the existence of a certain pyramidal central configuration.  相似文献   

Assessment of Water Quality in the Elbe River at Flood Water Conditions Based on Cluster Analysis,Principle Components Analysis,and Source Apportionment     

Martina Baborowski  Vasil Simeonov  Jürgen W. Einax 《洁净——土壤、空气、水》2012,40(4):373-380

An assessment of water quality measurements during a spring flood in the Elbe River is presented. Daily samples were taken at a site in the middle Elbe, which is part of the network of the International Commission for the Protection of the Elbe River (IKSE/MKOL). Cluster analysis (CA), principal components analysis (PCA), and source apportionment (APCS apportioning) were used to assess the flood‐dependent matter transport. As a result, three main components could be extracted as important to the matter transport in the Elbe River basin during flood events: (i) re‐suspended contaminated sediments, which led to temporarily increased concentrations of suspended matter and of most of the investigated heavy metals; (ii) water discharge related concentrations of pedogenic dissolved organic matter (DOM) as well as preliminary diluted concentrations of uranium and chloride, parameters with stable pollution background in the river basin; and (iii) abandoned mines, i.e., their dewatering systems, with particular influence on nickel, manganese, and zinc concentrations.  相似文献   

A Case Study of CO<Subscript>2</Subscript>, CO and Particles Content Evolution in the Suburban Atmospheric Boundary Layer Using a 2-μm Doppler DIAL,a 1-μm Backscatter Lidar and an Array of In-situ Sensors     

Fabien Gibert  Irène Xuéref-Rémy  Lilian Joly  Martina Schmidt  Juan Cuesta  Kenneth J. Davis  Michel Ramonet  Pierre H. Flamant  Bertrand Parvitte  Virginie Zéninari 《Boundary-Layer Meteorology》2008,128(3):381-401

A network of remote and in-situ sensors was deployed in a Paris suburb in order to evaluate the mesoscale evolution of the daily cycle of CO₂ and related tracers in the atmospheric boundary layer (ABL) and its relation to ABL dynamics and nearby natural and anthropogenic sources and sinks. A 2-μm heterodyne Doppler differential absorption lidar, which combines measurements of, (1) structure of the atmosphere, (2) radial velocity, and (3) CO₂ differential absorption was a particularly unique element of the observational array. We analyse the differences in the diurnal cycle of CO, CO₂, lidar reflectivity (a proxy for aerosol content) and H₂O using the lidar, airborne measurements in the free troposphere and ground-based measurements made at two sites located few kilometres apart. We demonstrate that vertical mixing dominates the early morning drawdown of CO and aerosol content trapped in the former nocturnal layer but not the H₂O and CO₂ mixing ratio variations. Surface fluxes, vertical mixing and advection all contribute to the ABL CO₂ mixing ratio decrease during the morning transition, with the relative importance depending on the rate and timing of ABL rise. We also show evidence that when the ABL is stable, small-scale (0.1-km vertical and 1-km horizontal) gradients of CO₂ and CO are large. The results illustrate the complexity of inferring surface fluxes of CO₂ from atmospheric budgets in the stable boundary layer.  相似文献   

Tree Coring as a Complement to Soil Gas Screening to Locate PCE and TCE Source Zones and Hot Spots          下载免费PDF全文

Mette Algreen  Stefan Trapp  Pernille Rehné Jensen  Mette Martina Broholm 《Ground Water Monitoring & Remediation》2015,35(4):57-66

Preliminary risk assessment for prioritisation of site investigations requires efficient screening to reveal type and level of contamination. The screening methods, tree coring and soil gas sampling were applied and compared at two forested sites contaminated with tetrachloroethylene (PCE) or trichloroethylene (TCE) to evaluate their ability to locate source zones and contaminant hot spots. One test site represented a relatively homogeneous sandy soil and aquifer, and the second a more heterogeneous geology with both sandy and less permeable clay till layers overlying a chalk aquifer. Tree cores from different tree species were sampled and analysed, and compared to soil gas measurements and existing soil gas data. Both methods were found useful as screening tools to locate hot spots of PCE and TCE in the shallow subsurface. Tree coring was found to be particularly beneficial as a complement to soil gas sampling at sites with low permeable soils, and where contamination was located in the capillary rise or shallow groundwater. The shorter time required for tree coring reduced the costs compared to soil gas sampling, but the sensitivity and precision of tree coring were lower. However, this did not affect the feasibility of using tree coring to locate the hot spots. Moreover, a combination of the two methods can help to focus any subsequent investigations like soil or groundwater sampling. The use of tree coring to complement soil gas sampling for pre‐screening is expected to result in higher certainty for revealing hot spots and source zones at contaminated sites.  相似文献