Exploring the use of caged Nucella lapillus to monitor changes to TBT hotspot areas: a trial in the River Tyne estuary (UK)

Caged dogwhelks (Nucella lapillus) and mussels (Mytilus edulis) were placed in situ at sites along the River Tyne (UK) in order to investigate the potential for monitoring any change in tributyltin (TBT) mediated effects. After 6 months the development of imposex was investigated in the dogwhelks and concentrations of TBT were determined in the whole tissues of both species. Sites within the estuary showed a high degree of imposex, whilst those at sites North and South of the estuary mouth exhibited significantly lower induction. Concentrations of TBT measured in the dogwhelk and mussel tissues showed the same pattern. The success of the caging technique, occurrence of imposex at other UK sites and the need for further monitoring at TBT impacted locations in the light of current international controls on the use of TBT-based antifouling paints on sea-going vessels are discussed.     

Exploring suitability for tropical crop cultivation in Hainan Island by SOTAL methodology

1 Introduction Land degradation is a major threat to environmental and agricultural quality of land[1] and is directly related to food security issues. An instrument for decision-makers to plan or stimulate allocation of land to users that can be sustained and are economically viable and socially acceptable. Different kinds of land are unequally suited to various uses. Land evaluation is the assessment of the suitability of a tract of land for a specified kind of use and it provides objective…     

钟丘洋火山热液型铜矿床地球化学异常特征

据钟丘洋火山热液型铜矿床的地层、侵入岩、矿石和矿体中元素的分布规律,阐明了该矿床的地球化学原生异常特征;确定了与矿床有关的指示元素及其分带序列;建立了矿床剥蚀程度的评价指标及该矿床的地球化学异常模式。     

The emergence of life from iron monosulphide bubbles at a submarine hydrothermal redox and pH front

Here we argue that life emerged on Earth from a redox and pH front at c. 4.2 Ga. This front occurred where hot (c. 150 degrees C), extremely reduced, alkaline, bisulphide-bearing, submarine seepage waters interfaced with the acid, warm (c. 90 degrees C), iron-hearing Hadean ocean. The low pH of the ocean was imparted by the ten bars of CO2 considered to dominate the Hadean atmosphere/hydrosphere. Disequilibrium between the two solutions was maintained by the spontaneous precipitation of a colloidal FeS membrane. Iron monosulphide bubbles comprising this membrane were inflated by the hydrothermal solution upon sulphide mounds at the seepage sites. Our hypothesis is that the FeS membrane, laced with nickel, acted as a semipermeable catalytic boundary between the two fluids, encouraging synthesis of organic anions by hydrogenation and carboxylation of hydrothermal organic primers. The ocean provided carbonate, phosphate, iron, nickel and protons; the hydrothermal solution was the source of ammonia, acetate, HS-, H2 and tungsten, as well as minor concentrations of organic sulphides and perhaps cyanide and acetaldehyde. The mean redox potential (delta Eh) across the membrane, with the energy to drive synthesis, would have approximated to 300 millivolts. The generation of organic anions would have led to an increase in osmotic pressure within the FeS bubbles. Thus osmotic pressure could take over from hydraulic pressure as the driving force for distension, budding and reproduction of the bubbles. Condensation of the organic molecules to polymers, particularly organic sulphides, was driven by pyrophosphate hydrolysis. Regeneration of pyrophosphate from the monophosphate in the membrane was facilitated by protons contributed from the Hadean ocean. This was the first use by a metabolizing system of protonmotive force (driven by natural delta pH) which also would have amounted to c. 300 millivolts. Protonmotive force is the universal energy transduction mechanism of life. Taken together with the redox potential across the membrane, the total electrochemical and chemical energy available for protometabolism amounted to a continuous supply at more than half a volt. The role of the iron sulphide membrane in keeping the two solutions separated was appropriated by the newly synthesized organic sulphide polymers. This organic take-over of the membrane material led to the miniaturization of the metabolizing system. Information systems to govern replication could have developed penecontemporaneously in this same milieu. But iron, sulphur and phosphate, inorganic components of earliest life, continued to be involved in metabolism.     

西藏冈底斯东段铜多金属成矿带综合物化探技术有效性试验

应用综合物化探方法在西藏冈底斯东段铜多金属成矿带驱龙、甲马矿区进行了方法有效性试验。介绍了野外方法试验采用的综合物化探技术及数据处理方法,对各方法的试验成果进行了综合对比分析,在此基础上展望了以DPEM、TEM方法为主的综合物化探方法在该区矿产资源勘查评价中的巨大应用潜力。     

Spatial and temporal infiltration dynamics during managed aquifer recharge

Natural groundwater recharge is inherently difficult to quantify and predict, largely because it comprises a series of processes that are spatially distributed and temporally variable. Infiltration ponds used for managed aquifer recharge (MAR) provide an opportunity to quantify recharge processes across multiple scales under semi-controlled conditions. We instrumented a 3-ha MAR infiltration pond to measure and compare infiltration patterns determined using whole-pond and point-specific methods. Whole-pond infiltration was determined by closing a transient water budget (accounting for inputs, outputs, and changes in storage), whereas point-specific infiltration rates were determined using heat as a tracer and time series analysis at eight locations in the base of the pond. Whole-pond infiltration, normalized for wetted area, rose rapidly to more than 1.0 m/d at the start of MAR operations (increasing as pond stage rose), was sustained at high rates for the next 40 d, and then decreased to less than 0.1 m/d by the end of the recharge season. Point-specific infiltration rates indicated high spatial and temporal variability, with the mean of measured values generally being lower than rates indicated by whole-pond calculations. Colocated measurements of head gradients within saturated soils below the pond were combined with infiltration rates to calculate soil hydraulic conductivity. Observations indicate a brief period of increasing saturated hydraulic conductivity, followed by a decrease of one to two orders of magnitude during the next 50 to 75 d. Locations indicating the most rapid infiltration shifted laterally during MAR operation, and we suggest that infiltration may function as a "variable source area" processes, conceptually similar to catchment runoff.     

Isotopic and microbial indicators of sewage pollution from Stone Town, Zanzibar, Tanzania

In Stone Town, Zanzibar, sewage treatment is minimal, with a biological oxygen demand reduction to 60% and no removal of bacteria or nutrients. Here, Stone Town's sewage pollution was studied by measuring Enterococci and NH(4)(+) concentrations in seawater and δ(15)N of benthic organisms; samples were collected along the Stone Town shoreline and from offshore coral reefs. Public perceptions of sewage pollution were investigated via interviews. Enterococci from the Stone Town shoreline exceeded USEPA guidelines for recreational use. Benthic organisms from two of the four reefs were relatively enriched (δ(15)N>10 ‰), indicative of sewage derived N. δ(15)N values of organisms from Stone Town exceeded 16 ‰. A strong correlation was found between Enterococci and δ(15)N across sites, while step-wise regression indicated rainfall and tidal stage as important predictors for bacterial concentrations. These data provide an important impact assessment from which the efficacy of future policy and management change can be assessed.     

Ecological status assessment in the lower Eo estuary (Spain). The challenge of habitat heterogeneity integration: a benthic perspective

The implementation of the European Water Framework Directive (WFD) requires evaluation of the ecological status (ES) of benthic communities in coastal and transitional water systems, and the intercalibration of assessment methodologies therefore becomes a research challenge. Our aim was to test the suitability of applying the M-AMBI index to assess the status of the Eo estuary (northern coast of Spain). Our results showed that M-AMBI was influenced by the natural variability of benthic communities, and presented an apparent dependence on habitat characteristics. Consequently, the definition of homogeneous areas in transitional water systems should be based on the salinity gradient combined with other factors. To achieve an accurate ES assessment, habitat-specific reference conditions should then be defined prior to the application of M-AMBI; this necessitates dividing an estuary into several sections, which may be classified as different ESs. From this perspective, a novel approach to integrate habitat heterogeneity in a global ES assessment was tested.