The role of algae in the stabilization of coastal dune blowouts

A number of mechanisms prevent blowouts in the dunes along the Dutch-coast from growing beyond a certain length. Plants play an important role in the stabilization process. Algae are the first plants to colonize the blowouts. Their filaments are surrounded by mucilaginous sheaths which adhere to the sand grains and increase the resistance of the sand to entrainment by wind. This suggests that artificially induced algal growths might be used in cheap, and ecologically justifiable, stabilization measures.     

Treatment of broad palaeodose distributions in OSL dating of dune sands from the western Murray Basin, South Australia

Preliminary results of an optically stimulated luminescence dating study in the western Murray Basin in semi-arid south-eastern Australia are presented. The ultimate objective of the dating study is a reconstruction of dune formation indicative of palaeoclimatic changes in this region. So far, one site has been dated using the single-aliquot regenerative (SAR) dose protocol for quartz. A high scatter in individual palaeodoses was observed, which is unexpected in supposedly well bleached aeolian deposits. Therefore other sources of variability such as microdosimetry and bioturbation have to be taken into account. Nevertheless, the resulting ages are in chronostratigraphic order and document a long aeolian record from 180 to 9 ka.     

Late Holocene Mediterranean coastal change along the Tiber Delta and Roman occupation of the Laurentine shore, central Italy

A line of Roman villas once dominated the Mediterranean coastline to the south of the Tiber river mouth near Ostia in central Italy. The Roman remains, which were constructed within a series of dune ridges, now lie up to 900 m from the current shoreline as a result of the continued evolution of the Tiber delta in response to postglacial sea level rise, sediment inputs from the Tiber river catchment and tectonic uplift. Infrared stimulated luminescence (IRSL) ages of potassium-rich feldspars extracted from dune sands are in good agreement with the independent age control provided by the Roman structures and allow us to hypothesise an increase in aggradation rates of five times since the end of the period of Roman occupation compared with the earlier Holocene.     

Topographic changes associated with coastal dune blowouts at island beach state park,New Jersey

Topographic changes in two blowouts located in Island Beach State Park, New Jersey, USA were monitored over the winter of 1981-1982. Elevation changes were measured with erosion pins, and sediment traps placed at comparable locations in each blowout monitored the amount of sand moved by the wind. Discrete wind events were identified from regional data, and morphological data for the intervals with the highest onshore and offshore wind speeds are examined in detail. Vegetation is the primary influence on the development of the two blowouts. Blowout A is characterized by eroding sidewalls, a stable base, and an accreting blowout rim. High rates of sediment transport occur through the blowout throat which results in accretion on the vegetated rim. This blowout is an active sediment transfer system. Vegetation causes a large amount of deposition in the throat of blowout B. As vegetation was buried over the winter, the area of deposition migrated inland. Sidewall erosion also occurred in blowout B. Little change was recorded on the blowout rim. Blowout B is a recovering system where sediment is delivered to the blowout floor from the beach by onshore winds and from the blowout rim by offshore winds where it is stabilized by vegetation. The development of foredune blowouts is governed largely by vegetation cover on the dune crest and by sidewall erosion during offshore and onshore winds. Blowout recovery depends on vegetation growth and sediment deposition in the throat, and on the role of the sidewalls as sources of sediment which is deposited elsewhere within the system. Foredune blowouts are dynamic systems in which positive feedbacks in sediment availability and vegetation growth lead to a cycle of development and closure.     

Geomorphic activity of rabbits on a coastal sand dune,De Blink dunes,the Netherlands

A study of the erosion rate and the stability of sandy slopes was conducted on an eastern arm of a parabolic coastal sand dune, De Blink, central Netherlands. The contribution of rabbits to these processes was found to depend on two types of activity; the building of caves and sand mounds of up to 1·5 m² in area; and the digging of shallow burrows, whereby amounts of sand up to 1 kg per burrow were excavated. The burrowing activity was found over the whole dune, while cave holes were dug mainly on the northern slope. The total amount of sand actually transported on the dune due to this activity is not clear yet, but their influence on the development of stepped slopes is well established.     

International aspects of invasive species management: a research agenda

We propose a research agenda for studying six basic questions about the impacts of alternate international invasive species control mechanisms on economic agents in a nation such as the USA. The six questions are as follows. First, when can one justify a trade ban as an effective regulatory policy? Second, what are the properties of control rules that vary by port of entry and whether a shipment is viewed as a routine or as a first-time entry? Third, when should a port manager in the USA use information about the dollar value of the products being transported by ships from two exporting firms and the expected time it takes to inspect ships from these two firms to grant preferential treatment to one or the other firm? Fourth, what are some reasonable measures of the trade related risk from invasive species? Fifth, how useful is strategic trade policy as an invasive species management tool? Finally, when analyzing a biological invasion, is it more appropriate to focus on the likelihood of this event or, instead, on the magnitude of the event?     

Linking 1D coastal ocean modelling to environmental management: an ensemble approach

The use of a one-dimensional interdisciplinary numerical model of the coastal ocean as a tool contributing to the formulation of ecosystem-based management (EBM) is explored. The focus is on the definition of an experimental design based on ensemble simulations, integrating variability linked to scenarios (characterised by changes in the system forcing) and to the concurrent variation of selected, and poorly constrained, model parameters. The modelling system used was previously specifically designed for the use in “data-rich” areas, so that horizontal dynamics can be resolved by a diagnostic approach and external inputs can be parameterised by nudging schemes properly calibrated. Ensembles determined by changes in the simulated environmental (physical and biogeochemical) dynamics, under joint forcing and parameterisation variations, highlight the uncertainties associated to the application of specific scenarios that are relevant to EBM, providing an assessment of the reliability of the predicted changes. The work has been carried out by implementing the coupled modelling system BFM-POM1D in an area of Gulf of Trieste (northern Adriatic Sea), considered homogeneous from the point of view of hydrological properties, and forcing it by changing climatic (warming) and anthropogenic (reduction of the land-based nutrient input) pressure. Model parameters affected by considerable uncertainties (due to the lack of relevant observations) were varied jointly with the scenarios of change. The resulting large set of ensemble simulations provided a general estimation of the model uncertainties related to the joint variation of pressures and model parameters. The information of the model result variability aimed at conveying efficiently and comprehensibly the information on the uncertainties/reliability of the model results to non-technical EBM planners and stakeholders, in order to have the model-based information effectively contributing to EBM.     

Hydraulics and bedload in unsteady flow:Example of the Volga River

The current paper deals with the navigable section of the Volga River tailwater of the Nizhny Novgorod Hydropower Plant.To ensure navigation in this area,the existing navigation structures are being reconstructed and an additional chamber of the Gorodets Navigation Lock is to be constructed,and an extended navigable channel in the Volga River is to be created.To assess the impact of the planned measures on hydrological and riverbed regimes,the hydromorphological situation has been analyzed,and the flow parameters and the water level regime in the tailwater pool of the hydro system have been studied.An analysis of the changes in the riverbed along the design channel path was done and the kinematics of the flow and sediment transport parameters were studied under conditions of unsteady water movement resulting from the daily regulation of the river flow.Numerical experi-ments have revealed the peculiarities of river sediment movement under conditions of unsteady water movement,and recommendations for modeling river bed deformation under such conditions have been developed.It was found that with daily and weekly regulation of river,discharge bedload transport becomes more active at the moment when a wave of daily release from the upper reaches of the hydrosystem passes through.The basic characteristics of bedload transport,i.e.,dune velocity and bedload rate,increase in comparison with a steady water flow.Under the conditions of unsteady water movement due to the daily regulation of the river flow,there are no strong changes in the size of the bottom dunes,while their velocity,and,consequently,the bedload rate increases significantly during periods when the wave of daily water releases from upstream passes.The results obtained indicate that for hydraulic calculations of the characteristics of water movement and sediment transport,it is necessary to use data from hourly observations of flow rates and water levels.It was found that during the passage of release waves under daily flow regulation,there are short periods of increase in Froude number values.Similarly,the bedload rate increased during these periods compared to the average daily values.The result of this comparison ultimately led to the recommendation that daily flow regulation should be abandoned in order to reduce the intensity of bedload transport rate and channel erosion in the tailwater of the hydrosystem.     

Impacts of pollution on coastal and marine ecosystems including coastal and marine fisheries and approach for management: a review and synthesis

The history of aquatic environmental pollution goes back to the very beginning of the history of human civilization. However, aquatic pollution did not receive much attention until a threshold level was reached with adverse consequences on the ecosystems and organisms. Aquatic pollution has become a global concern, but even so, most developing nations are still producing huge pollution loads and the trends are expected to increase. Knowledge of the pollution sources and impacts on ecosystems is important not only for a better understanding on the ecosystem responses to pollutants but also to formulate prevention measures. Many of the sources of aquatic pollutions are generally well known and huge effort has been devoted to the issue. However, new concepts and ideas on environmental pollution are emerging (e.g., biological pollution) with a corresponding need for an update of the knowledge. The present paper attempts to provide an easy-to-follow depiction on the various forms of aquatic pollutions and their impacts on the ecosystem and organisms.     

Integrated river basin management, ICT and DSS: Challenges and needs

River basin management is a complex task. Therefore, instruments that help to assess the present situation and assist in the development and evaluation of solutions may be important. Since several decades and after the implementation of the first compulsory legal environments and institutional organizations for IWRM and IRBM, the need for an efficient support in the different decision-making processes has emerged. After several experiences, the demonstration of the interest of ICT and DSS systems is obvious in the water resources management domain. However and until now, most of the efforts have been focused on the theoretical aspects with very few integrations into operational approaches. The implementation of the new European water framework directive (2000) represents today one key example from which some lessons can be learned in the way of definition and use of ICT and DSS systems for IWRM and IRBM. The paper presents the concepts available through ICT and DSS. The example of the WFD is used to underline the challenges and the difficulties for the elaboration of new tools - DSSs - which could be able to answer of the challenges of IWRM and IRBM.     

Testing the applicability of a standardized growth curve (SGC) for quartz OSL dating: Kalahari dunes,South African coastal dunes and Florida dune cordons

Standardized growth curves (SGCs) have recently been developed as a means to reduce measurement times when determining palaeodoses in the standardized luminescence (OSL) dating of quartz, but this approach is not without its critics. We test the performance of SGCs derived from samples from a range of environments in southern Africa and Florida (United States of America). Data presented here suggest that the method performed well when determining low (<50 Gy) equivalent dose (D_e) values from samples with different geological provenances within South Africa. However, the application of an SGC built from South African data performed poorly when used to estimate the palaeodoses of samples from Florida, with seven out of ten samples failing to replicate the single aliquot regenerative (SAR)-derived D_e value to within ±10%. We thus advocate the use only of regionally based SGCs for full D_e determination, although SGCs can also be utilized as a way of quickly generating SAR ‘range finders’ irrespective of sample origin. Furthermore, one sample from the Florida site did not show regenerative growth in accordance with any samples from either the South Africa or Florida data, resulting in significant D_e underestimation when using the SGC. Although the reasons for such behaviour are not yet understood, this re-iterates the recommendation of Burbidge et al. [2006. D_e determination for young samples using the standardised OSL response of coarse-grain quartz. Radiation Measurements 41(3), 278], to incorporate a single regenerative step in SGC protocols in order to check consistency.     

Integrated urban and rural water affairs management reform in China: Affecting factors

The institutional evolution is often induced by some factors. This paper intends to analyze the affecting factors in integrated urban and rural water affairs management reform in China. The integrated urban and rural water affairs management reform is to restructure the governmental organizational setting in water management by forms of water affair bureau or re-designing functions of current water resources bureau to incorporate part or all functions of resources management, service regulation and environment management in water sector. The analyses selected some natural and socio-economic factors. The results point out that the integrated urban and rural water affairs management reform is a factor-induced institutional evolution. The factors promoting this reform include occasional drought events, higher central water investment percentage; but the data from the urban sector do not provide the support to the reform.     

Assessing coastal benthic macrofauna community condition using best professional judgement - Developing consensus across North America and Europe

Benthic indices are typically developed independently by habitat, making their incorporation into large geographic scale assessments potentially problematic because of scaling inequities. A potential solution is to establish common scaling using expert best professional judgment (BPJ). To test if experts from different geographies agree on condition assessment, sixteen experts from four regions in USA and Europe were provided species-abundance data for twelve sites per region. They ranked samples from best to worst condition and classified samples into four condition (quality) categories. Site rankings were highly correlated among experts, regardless of whether they were assessing samples from their home region. There was also good agreement on condition category, though agreement was better for samples at extremes of the disturbance gradient. The absence of regional bias suggests that expert judgment is a viable means for establishing a uniform scale to calibrate indices consistently across geographic regions.     

Cutting management of riparian vegetation by using hydrodynamic model simulations

This study numerically investigates effects of cutting riparian vegetation on flow characteristics by using a two-dimensional numerical model. The numerical model is based on depth-averaging the time- and volume-averaged Navier–Stokes equation with turbulent effects determined by the standard k–ε turbulence model. Drag forces exerted by the flow on vegetation are considered by adding source terms into momentum equations. In a rectangular channel and compound channel with vegetation along one side, numerical predictions show are in good agreement with those of previous studies. Five cutting scenarios, including the original, cutting along the main channel side, cutting along the bank side, alternative cutting, and reducing vegetative density, are analyzed in this study. The influences of the cutting scenarios on hydrodynamic behaviors are evaluated via numerical simulations. Simulation results suggest that cutting along the main channel side is the most effective scenario for reducing water depth and flow velocities.     

地震前兆仪器管理系统建设

长期以来,对前兆台网仪器的管理缺乏系统性。为此,研发了前兆仪器管理系统。该系统实现了对前兆仪器从购买到淘汰整个生命周期的管理,其中包括安装、接入、运行、故障、停测、报废等,以及仪器故障维修流程的管理,其中包括故障登记、处理、维修、备机备件库等。基于这些信息,对仪器及故障维修情况进行综合统计分析,为管理决策提供信息支持。本文主要介绍了该系统设计的一些主要技术方面和系统实现的主要功能。     

Evaluating ecosystem-based management options: Effects of trawling in Torres Strait,Australia

A suite of management options for a prawn trawl fishery in Torres Strait, Australia was assessed for impacts on the benthic fauna using a dynamic management strategy evaluation approach. The specification of the management options was gained through consultation with stakeholders. Data for the model was drawn from several sources: the fleet data from fishery logbooks and satellite vessel monitoring systems, benthic depletion rates from trawl-down experiments, benthic recovery rates from post-experiment recovery monitoring studies, and benthic distribution from large-scale benthic surveys. Although there were large uncertainties in the resulting indicators, robust measures relevant to management were obtained by taking ratios relative to the status quo. The management control with the biggest effect was total effort; reducing trawl effort always led to increases in benthic faunal density of up to 10%. Spatial closures had a smaller benefit of up to 2%. The effect of closing a set of buffer zones around reefs to trawling was indistinguishable from the status quo option. Closing a larger area, however, was largely beneficial especially for sea cucumbers. When the spatial distributions of fauna prior to fishing were accounted for, fauna with distributions positively correlated with effort improved relative to those negatively correlated. The reduction in prawn catch under effort reduction scenarios could be ameliorated by introducing temporal closures over the full-moon period.     

Ecosystem service provision: an operational way for marine biodiversity conservation and management

Since no extensive conceptual framework has been developed on the issues of ecosystem service (ES) and service provider (SP) in the marine environment, we have made an attempt to apply these to the conservation and management of marine biodiversity. Within this context, an accurate individuation of SPs, namely the biological component of a given ecosystem that supports human activities is fundamental. SPs are the agents responsible for making the ES-based approach operational. The application of these concepts to the marine environment should be based on an model different to the terrestrial one. In the latter, the basic model envisages a matrix of a human-altered landscape with fragments of original biodiversity; conversely, in the marine environment the model provides fragments where human activities are carried out and the matrix is represented by the original biodiversity. We have identified three main classes of ES provision: in natural, disturbed and human-controlled environments. Economic valuation of marine ESs is an essential condition for making conservation strategies financially sustainable, as it may stimulate the perceived need for investing in protection and exploitation of marine resources.     

Using very high resolution remote sensing for the management of coral reef fisheries: Review and perspectives

Coral reef fisheries are critical for food security and as a source of income in developing and developed countries, but they are collapsing in many areas. Following the emergence and routine availability of commercial very high spatial resolution (0.6-10 m) multispectral satellite images, we reviewed the use of these new high-quality remote sensing data and products for coral reef fisheries management. The availability of habitats maps improves management by guiding sampling strategies, mapping resources, involving local communities, identifying conservation areas, and facilitating Ecosystem Based Fishery Management (EBFM) approaches. However, despite their potential, very little use of products designed specifically for fishery management can be reported, likely due to high costs, inherent technology limitations and lack of awareness on the possibilities. Given the theoretical benefits brought by relevant habitat maps in EBFM frameworks, we advocate the use of adequate remote sensing products that integrate fishery technical services demands and local requirements.     

Effects of fish farm waste on Posidonia oceanica meadows: synthesis and provision of monitoring and management tools

This paper provides a synthesis of the EU project MedVeg addressing the fate of nutrients released from fish farming in the Mediterranean with particular focus on the endemic seagrass Posidonia oceanica habitat. The objectives were to identify the main drivers of seagrass decline linked to fish farming and to provide sensitive indicators of environmental change, which can be used for monitoring purposes. The sedimentation of waste particles in the farm vicinities emerges as the main driver of benthic deterioration, such as accumulation of organic matter, sediment anoxia as well as seagrass decline. The effects of fish farming on P. oceanica meadows are diverse and complex and detected through various metrics and indicators. A safety distance of 400 m is suggested for management of P. oceanica near fish farms followed by establishment of permanent seagrass plots revisited annually for monitoring the health of the meadows.     

The use of phytoplankton patterns of diversity for algal bloom management

Many biotic and abiotic processes contribute to variability in phytoplankton diversity in aquatic ecosystems. Depending on their intensity and on their frequency, these may drive non-equilibrium dynamics and enhance the species diversity. Different studies propose that biodiversity buffers ecosystem functioning against environmental fluctuations leading to more predictable aggregate community or ecosystem properties. Salto Grande reservoir is polymictic and eutrophic with recurrent summer cyanobacterial blooms. The aim of this study was to determine the key variable(s) related with phytoplankton diversity in order to predict the possible occurrence of an algal bloom at the ecosystem. A preliminary analysis of the data matrix suggested non-linear relationships between diversity and the selected variables: phytoplankton abundance and the vertical attenuation coefficient (Kd). The best function fitting of the scatter plot of phytoplankton diversity versus phytoplankton abundance was a rational function. The inflection point of phytoplankton diversity estimated by the second derivate of this function was 2.7 bit cell⁻¹ which corresponded to an abundance of 3000 cells ml⁻¹. The relationship of phytoplankton diversity and vertical attenuation coefficient values also show a humped distribution pattern (Gauss function). The inflection point of this function corresponded to a diversity value of 1.9 bit cell⁻¹ and 2.5 m⁻¹ for Kd. These inflection points were, respectively, related with the resource competition among the present species and the light limitation conditions. The showed patterns of diversity and the estimated threshold values could be integrated to construct a predictive model for the reservoir based on phytoplankton diversity and the probable ambient conditions of the reservoir.