Development of predictive models for determining enterococci levels at Gulf Coast beaches

The US EPA BEACH Act requires beach managers to issue swimming advisories when water quality standards are exceeded. While a number of methods/models have been proposed to meet the BEACH Act requirement, no systematic comparisons of different methods against the same data series are available in terms of relative performance of existing methods. This study presents and compares three models for nowcasting and forecasting enterococci levels at Gulf Coast beaches in Louisiana, USA. One was developed using the artificial neural network (ANN) in MATLAB Toolbox and the other two were based on the US EPA Virtual Beach (VB) Program. A total of 944 sets of environmental and bacteriological data were utilized. The data were collected and analyzed weekly during the swimming season (May-October) at six sites of the Holly Beach by Louisiana Beach Monitoring Program in the six year period of May 2005-October 2010. The ANN model includes 15 readily available environmental variables such as salinity, water temperature, wind speed and direction, tide level and type, weather type, and various combinations of antecedent rainfalls. The ANN model was trained, validated, and tested using 308, 103, and 103 data sets (collected in 2007, 2008, and 2009) with an average linear correlation coefficient (LCC) of 0.857 and a Root Mean Square Error (RMSE) of 0.336. The two VB models, including a linear transformation-based model and a nonlinear transformation-based model, were constructed using the same data sets. The linear VB model with 6 input variables achieved an LCC of 0.230 and an RMSE of 1.302 while the nonlinear VB model with 5 input variables produced an LCC of 0.337 and an RMSE of 1.205. In order to assess the predictive performance of the ANN and VB models, hindcasting was conducted using a total of 430 sets of independent environmental and bacteriological data collected at six Holly Beach sites in 2005, 2006, and 2010. The hindcasting results show that the ANN model is capable of predicting enterococci levels at the Holly Beach sites with an adjusted RMSE of 0.803 and LCC of 0.320 while the adjusted RMSE and LCC values are 1.815 and 0.354 for the linear VB model and 1.961and 0.521 for the nonlinear VB model. The results indicate that the ANN model with 15 parameters performs better than the VB models with 6 or 5 parameters in terms of RMSE while VB models perform better than the ANN model in terms of LCC. The predictive models (especially the ANN and the nonlinear VB models) developed in this study in combination with readily available real-time environmental and weather forecast data can be utilized to nowcast and forecast beach water quality, greatly reducing the potential risk of contaminated beach waters to human health and improving beach management. While the models were developed specifically for the Holly Beach, Louisiana, the methods used in this paper are generally applicable to other coastal beaches.     

The Problem of Scale

Sean Godsell has built an international reputation on designing finely crafted houses in southeast Australia for which he draws all the details by hand. Here he explains how landing the commission for the Design Hub, a new postgraduate design research centre for RMIT in Melbourne, required a shift in scale and also a change in working conditions as he encountered new production processes and levels of regulation. Maintaining the character of the building as something ‘made’ rather than produced was a sustained battle.     

Microplastic contamination of sediments across and within three beaches in western Lake Superior

Microplastic pollution of the environment is ubiquitous, but the processes by which microplastics accumulate within beach sediments are not yet well understood. We isolate microplastic pollution from the sediments at three western Lake Superior beaches. Samples of both surface and subsurface sediments are considered. We find that the average microplastic contamination is 65 microplastic particles kg^?1 sediment across our sites with significant variability across beaches, but the microplastic composition is always dominated by polyester fibers. The variation across beaches does not seem to relate to the distance from suspected sources of microplastics to the lake. Within each beach, we find no significant variation of the mean microplastic concentration in the cross-shore direction or in the surface vs. subsurface sediments at the wrack line. We interpret this mean microplastic concentration in the sediment as a measure of the bulk microplastic concentration in the nearshore water at each beach. In subsurface sediments, we observe a significant difference in the variance of microplastic concentrations, and we attribute this variation to the intermittency of the extreme hydrodynamic conditions that deposit microplastics deeper into the sediment.     

某海滨铁砂矿流态化气基还原—高温熔分试验

为了确定印度尼西亚某海滨铁砂矿的合理开发利用方案,在模拟流化床的竖直管式炉内,以CO与H2的混合气体为还原剂,对该海滨铁砂矿进行了直接还原试验,并对最佳条件下的还原产物进行了熔分条件试验。结果表明:1反应温度和还原气氛对还原效果影响显著,在还原温度为900℃、还原气体H2和CO的体积比为7∶3、还原时间为80 min情况下,还原产物中铁的还原度为96.11%、铁的金属化率为93.40%。2确定条件下的还原产物适宜的熔分温度为1 570℃、碱度为1.2、熔分时间为15 min,对应的铁回收率为92.99%。因此,流态化气基还原—高温熔分工艺是该海滨铁砂矿开发利用的有效工艺。     

某海滨砂矿重选毛砂工艺矿物学研究

采用化学分析、显微镜和MLA矿物自动检测技术等手段,对某海滨砂矿重选毛砂进行工艺矿物学研究．结果表明：该毛砂中有价矿物种类多,包括钛铁矿、金红石、锆石、独居石、钛赤铁矿和磁铁矿等;自然粒度范围较窄,各主要回收矿物的粒度大小相近,主要集中在0．04～0．125 m m之间;金红石、锆石、独居石均具良好的可分离性,钛铁矿和钛赤铁矿矿物量之比约为6．5∶1,二者磁性、密度及表面性质十分相近,需采用还原焙烧法将钛赤铁矿还原为具强磁性的磁铁矿,而钛铁矿无变化,再采用弱磁分选．     

Beach protection and restoration part I: hard structures and Beach erosion

Coastal erosion is a world‐wide occurrence, principally along sea shores but also seen along many lake shorelines. It has been reported in the literature for several decades that it entails considerable economic consequences, for instance endangers valuable properties. The rise in water level is a major cause of the phenomenon, but anthropic actions have also played an important part. Stopping coastal erosion and halting shoreline retreat is considered impossible. Reducing the rate of erosion and restoring endangered areas, on the other hand, falls within the reach of coastal engineers. Various approaches have been tried with unequal success and, occasionally, with undesired if not unexpected consequences.     

Beach protection and restoration Part II: a perspective of “soft” methods

In Part I (Vide previous issue) the authors underscored the world‐wide character of coastal erosion and particularly the shrinking of beaches. If nature is the causal agent, man clearly enhances the process. To counter the steady encroachment of the sea upon the land, several protective devices have been placed along the shores. Some of these were even conceived as means to bring about sand accretion in specific sites.

The results have been overall disappointing, or of local value only. In this paper beach protection and beach restoration methods that call upon the natural processes are examined. The “soft” approach to the problem includes implanting artificial reefs, placing vegetation, or fences, on dune or beach, and especially artificial beach nourishment.     

Increasing sustainability of coastal management by merging monitored marine environments with inventoried shelf resources

Biological and physical coastal surveys are traditionally separated by disciplines but the integration of apparently disparate surveys into cohesive biophysical surveys has comparative advantage. The paper reviews methods of assessment and offers an integrated approach to realistic short‐term goals of sustainable management within the overarching context of unsustainable long‐term sustainability.     

Organic matter recycling in a beach environment influenced by sunscreen products and increased inorganic nutrient supply (Sturla, Ligurian Sea, NW Mediterranean)

The beaches are sites where the human influence may be strong and the beach ecosystems have often shown a high sensibility to environmental alterations. These zones may be affected by a large series of anthropogenic-derived pressures, such as unbalanced inorganic nutrient input, that may cause anomalous development of primary production, altering the structure of the trophic webs. Furthermore, the utilisation of cosmetic sunscreen products is reaching unexpected levels, thus assuming a potentially important as well as unknown role in the contamination of marine environments. The present study was planned to test the response of the beach ecosystem to increases in inorganic nutrients (nitrate and phosphate) and to the input of a widely used cosmetic sunscreenproduct. A short-term laboratory experiment was carried out on microsystems consisting of sediments and seawater from the swash zone of a Ligurian city beach (Sturla). The processes related to organic matter (OM) recycling and some microbial food web components (bacteria and micro-autotrophic organisms) were analysed. The multivariate statistical analysis of the results showed that the increase in inorganic nutrients and sunscreen caused only a transient alteration in the OM recycling processes in the seawater. The sedimentary processes, instead, were different in the different systems, although starting from the same condition. In the sediment, surprisingly, an increase in inorganic nutrients did not lead to an increase in the primary biomass nor to significantly higher bacterial abundance, while the sunscreen caused increased OM recycling, especially devoted to protein and lipid mobilisation, supporting a growing bacterial and autotrophic community by reducing the bottom-up pressure. Additional toxicity tests performed on protozoa highlighted that, while the inorganic nutrients seemed to show no effects, sunscreen decreased the protozoan viability, thus likely favouring microautotrophic and bacterial increases by reducing the top-down pressure.