Boron isotopes as an artificial tracer

A field study was conducted using a combination of intrinsic and artificial tracers to estimate travel times and dilution during transport of infiltrate from a reclaimed water infiltration basin to nearby monitoring wells. A major study objective was to validate boric acid enriched in (10)B as an artificial tracer. Basin 10E at the Rio Hondo Spreading Grounds in Whittier, California, was the site of the test. The basin normally receives a mixture of treated municipal waste water, purchased State Project water, and local runoff from the San Gabriel River. Approximately 3.5 kg of (10)B-enriched boric acid was dispersed among 2.05 x 10(5) m(3) of basin water to initiate the experiment. The resultant median delta(11)B in the infiltration basin was -71 per thousand. Prior to tracer addition, the basin water had an intrinsic delta(11)B of +2 per thousand. Local monitoring wells that were used to assess travel times had delta(11)B values of +5 per thousand and +8 per thousand at the time of tracer addition. Analytic results supported an assumption that boron is conserved during ground water transport and that boron enriched in (10)B is a useful artificial tracer. Several intrinsic tracers were used to reinforce the boric acid tracer findings. These included stable isotopes of oxygen (delta(18)O) and hydrogen (deltaD), sulfate concentration, and the boron to chloride ratio. Xenon isotopes, (136)Xe and (124)Xe, also supported boron isotope results. Xenon isotopes were added to the recharge basin as dissolved gases by investigators from the Lawrence Livermore National Laboratory.     

Quantity, composition, and source of sediment collected in sediment traps along the fringing coral reef off Molokai, Hawaii

Sediment traps were used to evaluate the frequency, cause, and relative intensity of sediment mobility/resuspension along the fringing coral reef off southern Molokai (February 2000-May 2002). Two storms with high rainfall, floods, and exceptionally high waves resulted in sediment collection rates>1000 times higher than during non-storm periods, primarily because of sediment resuspension by waves. Based on quantity and composition of trapped sediment, floods recharged the reef flat with land-derived sediment, but had a low potential for burying coral on the fore reef when accompanied by high waves. The trapped sediments have low concentrations of anthropogenic metals. The magnetic properties of trapped sediment may provide information about the sources of land-derived sediment reaching the fore reef. The high trapping rate and low sediment cover indicate that coral surfaces on the fore reef are exposed to transient resuspended sediment, and that the traps do not measure net sediment accumulation on the reef surface.     

泽头镇推出养虾新举措

泽头镇是山东省文登市的对虾养殖大镇,近几年,他们先后推广了大棚暂养、两茬虾养殖等先进技术。为进一步解决虾病的困扰,他们经过多方考察、论证,在全镇划出800亩虾池做为“实验田”,通过“长池改方池、大池改小池、浅池改深池”的虾池改造,大大促进了池内水体的循     

How good is good? Human values and Europe's proposed Marine Strategy Directive

The adoption of the proposed European Marine Strategy Directive is an opportunity for a comprehensive policy for protecting, improving and sustainably using Europe's environmentally degraded seas. It calls for an ecosystem-based approach to management where humans are regarded as a key system component. Although the proposed wording has been the subject of fierce debate, the central policy goal remains achieving "Good Environmental Status". The interpretation of "good" is key to implementation and relates to human values and worldviews. We demonstrate how these vary widely across Europe. Solution of fundamental considerations such as the assignation of reference states, the balance between precautionary and evidence-based action, the degree of subsidiarity, and conservation strategies including marine protected areas, will ultimately depend upon public understanding, involvement in and support for the Directive. The social element, critical to effective adaptive management, requires greater attention within the context of a regional seas geographical framework.     

5512—3铀矿床地质特征及成因分析

矿床产于浅变质志留系中。矿床受硅灰岩含矿层、断裂(具深断裂性质)、屏蔽构造控制。矿体成群以盲矿体为主,最大长360米,最大垂幅518米。主要矿物有沥青铀矿和铁钼镍锌铜钒汞等硫化物,沥青铀矿年龄1.173亿年～0.135亿年。 矿床硫氧碳同位素组成和矿物包体成分测定表示,成矿溶液为变质热液演化而来并有岩浆热液、壳下和慢源热流参与改造的广义热液。铀主要以碳酸铀酰络合物形式迁移。 矿床成因是地洼期强烈构造岩浆活动形成的广义热液,在开放系统中多期脉动性上升,遇屏蔽构造大量聚集,与大气源渗流交替、性质改变、缷荷的结果,多数矿体是叠加复成的。     

1300 micron continuum and C18O line mapping of the giant molecular cloud cores in Orion, W49, and W51

We present observations of the 1300 micron continuum emission and the C18O spectral-line emission from three well-studied giant molecular cloud cores: Orion, W49, and W51. The observations were obtained at the Five College Radio Astronomy Observatory, and they provide a means to examine the consistency of these two methods to trace the column density structure of molecular clouds. We find a good general correlation between the 1300 micron continuum, which traces the column density of dust, and the C18O J = 2 --> 1 line emission, which traces the column density of molecular gas, when the effects of source temperature are taken into consideration. Moreover, nominal values for the gas and dust abundances and the dust properties reproduce the observed continuum-to-line ratios. Thus, no strong C18O abundance gradients within sources has been found, and it appears that either the C18O emission lines or the submillimeter dust emission may be used to derive the mass column density within molecular clouds accurately.     

510—1铀矿床构造、地球化学特征及其成因探讨

本文根据510—1铀矿床形成的构造条件和地球化学特征,认为该富铀矿床的成因是地洼阶段壳幔混合型深源热液上升侵位,与贡巴—益哇逆冲推覆构造上盘中、下志留统羊肠沟组硅灰岩含水含矿层屏蔽构造相结合的结果。并指出古今统一的四维空间屏蔽构造是找矿的方向。     

Evaluation of bioremediation strategies of a controlled oil release in a wetland

A controlled petroleum release was conducted to evaluate bioremediation in a wetland near Houston, Texas. The 140-day study was conducted using a randomized, complete block design to test three treatments with six replicates per treatment. The three treatment strategies were inorganic nutrients, inorganic nutrients with an alternative electron acceptor, and a no-action oiled control. Samples were analyzed for petroleum chemistry and inorganic nutrients. These results are discussed in the context of our related research involving toxicology and microbiology at the site during the experiment. To evaluate biodegradation, the targeted compounds were normalized to the conservative compound C3017alpha, 21beta-[H]hopane, thus reducing the effects of spatial heterogeneity and physical transport. The two biostimulation treatments demonstrated statistically-higher rates of biodegradation than the oiled no-action control. For the majority of the experiment, target nutrient levels were maintained. Further research may be warranted to optimize these bioremediation strategies as well as evaluating additional treatment strategies for wetlands and other shoreline systems.