Concurrent Chemical and Histological Analyses: Are They Compatible?

Bivalves are often used as sentinel organisms in monitoring programmes for trace organic contaminants. the animal's physiological state may be important in interpreting trends in contaminant body burden. Simultaneous evaluation of physiological state and organic contaminant concentration in bivalves typically involves removal of a lipid-rich cross-section of the body mass for histopathological and/or gonadal analysis.

In this study, the bias introduced by this technique in the final trace organic concentrations, e.g. of polynuclear aromatic hydrocarbons, chlorinated pesticides and polychlorinated biphenyls, are evaluated on five different size groups of oysters. As a test case, we evaluated the use of this method in the NOAA's Status & Trends Mussel Watch (NS&T) Programme. the average biases introduced by this technique in the final trace organic concentrations in Gulf of Mexico oysters have been increasing since 1986 as a consequence of a continuous decrease in the size of the individuals sampled.     

Estimating Sustainable Bycatch Rates for California Sea Lion Populations in the Gulf of California

Abstract:  Commercial and subsistence fisheries pressure is increasing in the Gulf of California, Mexico. One consequence often associated with high levels of fishing pressure is an increase in bycatch of marine mammals and birds. Fisheries bycatch has contributed to declines in several pinniped species and may be affecting the California sea lion ( Zalophus californianus ) population in the Gulf of California. We used data on fisheries and sea lion entanglement in gill nets to estimate current fishing pressure and fishing rates under which viable sea lion populations could be sustained at 11 breeding sites in the Gulf of California. We used 3 models to estimate sustainable bycatch rates: a simple population-growth model, a demographic model, and an estimate of the potential biological removal. All models were based on life history and census data collected for sea lions in the Gulf of California. We estimated the current level of fishing pressure and the acceptable level of fishing required to maintain viable sea lion populations as the number of fishing days (1 fisher/boat setting and retrieving 1 day's worth of nets) per year. Estimates of current fishing pressure ranged from 101 (0–405) fishing days around the Los Machos breeding site to 1887 (842–3140) around the Los Islotes rookery. To maintain viable sea lion populations at each site, the current level of fishing permissible could be augmented at some sites and should be reduced at other sites. For example, the area around San Esteban could support up to 1428 (935–2337) additional fishing days, whereas fishing around Lobos should be reduced by at least 165 days (107–268). Our results provide conservation practitioners with site-specific guidelines for maintaining sustainable sea lion populations and provide a method to estimate fishing pressure and sustainable bycatch rates that could be used for other marine mammals and birds .     

An assessment of heavy-metal contamination in surface sediments of the Suez Gulf using geoaccumulation indexes and statistical analysis

An assessment of marine pollution due to metals was made in the Suez Gulf based on surface costal sediment collected from 18 locations along the Gulf. The samples were dried and acid-digested, and the metal contents (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were determined using a flame atomic absorption spectrophotometer (air-acetylene) with deuterium background correction. An evaluation of the heavy-metal pollution status of the Gulf was carried out using enrichment factors (EF) and geo-accumulation Indexes (I_geo). Also, heavy-metal concentrations in Suez Gulf sediments were evaluated using the Effect Range-Low (ERL) and the Effect Range-Median (ERM). The results of a Spearman correlation and factor and cluster analysis of the heavy metals analysed in the collected sediment were discussed. The main source of contamination is offshore oil field and industrial wastes, which arise due to the ineffective and inefficient operation equipments, illegal discharge and lack of supervision, and prosecution of offenders.     

Nutrient dynamics between sediment and overlying water in the inner part of Izmir Bay, Eastern Aegean

In this article a concept is described in order to predict and map the occurrence of benthic communities within and near the German Exclusive Economic Zone (EEZ) of the North Sea. The approach consists of two work steps: (1) geostatistical analysis of abiotic measurement data and (2) calculation of benthic provinces by means of Classification and Regression Trees (CART) and GIS-techniques. From bottom water measurements on salinity, temperature, silicate and nutrients as well as from punctual data on grain size ranges (0–20, 20–63, 63–2,000 μ) raster maps were calculated by use of geostatistical methods. At first the autocorrelation structure was examined and modelled with help of variogram analysis. The resulting variogram models were then used to calculate raster maps by applying ordinary kriging procedures. After intersecting these raster maps with punctual data on eight benthic communities a decision tree was derived to predict the occurrence of these communities within the study area. Since such a CART tree corresponds to a hierarchically ordered set of decision rules it was applied to the geostatistically estimated raster data to predict benthic habitats within and near the EEZ.     

Using vertebrate environmental DNA from seawater in biomonitoring of marine habitats

Conservation and management of marine biodiversity depends on biomonitoring of marine habitats, but current approaches are resource-intensive and require different approaches for different organisms. Environmental DNA (eDNA) extracted from water samples is an efficient and versatile approach to detecting aquatic animals. In the ocean, eDNA composition reflects local fauna at fine spatial scales, but little is known about the effectiveness of eDNA-based monitoring of marine communities at larger scales. We investigated the potential of eDNA to characterize and distinguish marine communities at large spatial scales by comparing vertebrate species composition among marine habitats in Qatar, the Arabian Gulf (also known as the Persian Gulf), based on eDNA metabarcoding of seawater samples. We conducted species accumulation analyses to estimate how much of the vertebrate diversity we detected. We obtained eDNA sequences from a diverse assemblage of marine vertebrates, spanning 191 taxa in 73 families. These included rare and endangered species and covered 36% of the bony fish genera previously recorded in the Gulf. Sites of similar habitat type were also similar in eDNA composition. The species accumulation analyses showed that the number of sample replicates was insufficient for some sampling sites but suggested that a few hundred eDNA samples could potentially capture >90% of the marine vertebrate diversity in the study area. Our results confirm that seawater samples contain habitat-characteristic molecular signatures and that eDNA monitoring can efficiently cover vertebrate diversity at scales relevant to national and regional conservation and management.     

Portuguese coastal zones and the new coastal management plans

Coastal zones in Portugal, as interface areas between land and sea, have problems related to the growing human pressure in terms of changes in land use associated with urban and industrial occupation, new accessibility (ports, motorways) and traffic flows, intensification of recreational use (beaches, water sports) and excessive fishing. Impacts include deterioration of water quality and sediments; alteration and degradation of natural habitats; new hydrodynamic situations; major landscape changes: and rapid changes in habits and way of life of the local populations and increased exposure of populations and assets to natural and induced risks (storms, accidents, spills, explosions). Plans for the Management of the Coastal Zone (POOC) have been developed and seven of them have been approved, while two similar plans are at a final stage of preparation. Together they cover the entire coast of Portugal. Their implementation and assessment could be a first step towards an integrated management of the Portuguese coastal zones. River Basin Management Plans (PBH) have been concluded and recently approved for the whole country. However, these plans do not consider estuarine systems and some other issues related to coastal systems. The National Water Plan (PNA) is under public presentation and discussion. Several ‘key messages’ are presented in this paper as a contribution for assessment of the proposals of this plan on issues related with coastal waters.     

水资源约束下西北干旱区城市扩张特征与变动趋势分析——以西陇海兰新经济带城市为例

论文以西北干旱区陇海兰新经济带城市为例,分析了城市水资源利用状况及其短缺程度,认为绝大多数城市“缺水又费水”,城市发展具有明显的“旱生性”。在水资源约束下,西陇海兰新经济带城市的发育程度远远落后于东部地区城市,也落后于全国城市平均水平,略好于西部地区城市,但明显好于西北地区城市,城市扩张的总体特征表现为以总量扩张为主,“农转非”空间和用地拓展空间大,以高耗低效扩张为主,水土资源投入产出效益普遍低下,城市发展处在主要依靠资源开发拉动经济增长的低级阶段,扩张质量有待提高。城市发展具有明显的外部推动性。未来20a,在水资源短缺的继续约束下,经济带城市扩张步伐将比较缓慢,扩张幅度将不会有大的变化。表现为将净增城市非农业人口6.31×106人,城市化水平将提高到35.97%,20a共净增7.21%,特大城市数量将保持西安、兰州和乌鲁木齐3个不变;大城市从无到有,将建成宝鸡、咸阳、铜川、天水、石河子和库尔勒6个;中等城市数量将会显著增加,由2000年的10个增加到2020年的14个,在不考虑“县改市”的前提下,小城市的数量将会进一步减少。为了确保经济带沿线城市的有序扩张,建议在城市建设过程中以人为本,以水为生命线,以经济发展为动力,以城市规划为法定依据。     

Environmental impacts of coastal aquaculture in eastern mediterranean bays the case of astakos gulf,Greece

GOAL, SCOPE AND BACKGROUND: Over the last decade Greece has become a leading country in the EU as concerns the cage farming of seabream and seabass. A strong debate has risen, however, about the environmental impacts of aquacultures in the coastal areas. The present paper deals with this problem and it is based on measurements of physico-chemical parameters in the water column, particulate matter and sediments in the area of Astakos Gulf, a coastal embayment in western Greece where three big fish farms are currently operating. METHODS: Water samples were collected by using Hydro-Bios sampling bottles, whereas a prototype sediment trap was installed under a fish cage for the collection of particulate matter. Temperature, dissolved oxygen, pH and salinity were measured in situ using portable equipment. Nutrients were determined by standard spectrophotometric methods. Trace metals were determined by Atomic Absorption Spectrometry. Dissolved organic carbon was determined by a Shimadzu 5000A carbon analyzer, whereas organic carbon in sediments was determined titrimetrically. RESULTS AND DISCUSSION: No clear eutrophication incidents have been identified, although the water column near the fish farms was enriched in nutrients and organic carbon. A sludge 'blanket' covers considerable parts of the seabed and is enriched in colloidal organic carbon and trace metals (Cd, Cu, Fe and Zn) that come from unused fish food. The biodegradation of this sludge leads to the development of anoxic conditions followed by the formation of undesirable gases, precipitation or remobilization of metals and the extinction of benthic fauna. CONCLUSION: The operation of fish farms at the coastal area of Astakos Gulf, and probably in similar Mediterranean gulfs, affects the marine environment, particularly in the vicinity of the cages. The most significant influence concerns the near-bottom water layer. The environmental impacts depend on the amount of food given to fishes, the mode of feeding, the fish density in cages, the annual production and the years of unit operation. The hydrology and the geomorphology of the area are also critical factors for its environmental quality. RECOMMENDATION AND OUTLOOK: The success of the fish-farming sector in the Mediterranean is accompanied by environmental and, in some extents, by social and marketing problems. These problems, derived from the rapid development of fish farming, can be solved only through an integrated management, using methods such as environmental impact assessment, risk assessment, economic evaluation, vulnerability assessments, resource accounting, cost-benefit analysis and outcome-based monitoring.     

不利风向条件下北部湾人为源对海口市PM2.5浓度影响的模拟研究

通过分析2013—2017年海口市风向频率、地面PM_(2.5)浓度及海口市所处北部湾地理位置,确定12月为北部湾对海口市最不利风向时间段.利用中尺度气象模式(WRF,Weather Research Forecast)驱动空气质量模型(CMAQ,Community Multi-scale Air Quality),设置一系列数值模拟情景,深入分析北部湾人为源对海口市PM_(2.5)浓度影响.结果表明:WRF/CMAQ能很好地再现北部湾气象场和PM_(2.5)浓度的时空分布.2013年12月,北部湾人为源对海口市PM_(2.5)平均贡献率约为45.4%,其中约有90%来源于海口市自身人为源,约有10%来源于广东广西片区,海南片区除海口外其余市县贡献可忽略不计.污染时段,北部湾和海口市自身贡献率均下降,平均贡献率分别为40%和36%,表明污染时段海口市PM_(2.5)主要源区不仅来自北部湾.通过分析后向轨迹,发现污染时段均会经过一个关键区——珠三角区域,表明珠三角区域很有可能也是造成2013年12月海口市PM_(2.5)污染的主要源区.清洁时段,北部湾和海口市自身贡献率均上升,平均贡献率分别为52%和48%,表明北部湾对海口市PM_(2.5)浓度影响在清洁时段更显著.因此,北部湾未来产业规划值得关注,因为这些产业很有可能使目前海口市清洁时段变为污染时段,导致空气质量下降.     

探讨“烟塔合一”技术在环评中大气环境的防护距离

归纳"烟塔合一"项目评估的共性要求,在分析德国模式不能充分反映特定条件下对近距离保护目标影响的基础上,阐明了环境防护距离设置的必要性,并就目前所采取环境防护距离计算方法及部分项目风洞试验结果进行解析,提出相关建议。