Freezing as a method of sample preservation for the analysis of dissolved inorganic nutrients in seawater

It is often desirable or necessary to store collected seawater samples prior to analysis for dissolved inorganic nutrients. It is therefore important to establish preservation and storage techniques that will ensure sample integrity and will not alter the precision or accuracy of analysis. We have performed a series of experiments on the storage of nutrient samples collected at the oligotrophic North Pacific benchmark Station ALOHA, using both standard autoanalyses and low-level techniques. Our results reveal that for oligotrophic oceanic waters, the immediate freezing of an unfiltered water sample in a clean polyethylene bottle is a suitable preservation method. This procedure is simple, it avoids potentially contaminating sample manipulations and chemical additions, and it adequately preserves the concentrations of nitrate + nitrite, soluble reactive phosphate, and soluble reactive silicate within a single water sample.     

Observation of the temperature structure function parameter,C T 2, over the ocean

Shipboard measurements of temperature fluctuations, mean wind, temperature, and humidity permit comparisons to be made of experimental and empirical estimates of c_t ², the temperature structure function parameter. Surface flux estimates are obtained from bulk aerodynamic formulae. Temperature fluctuation data are selected to minimize a salt-contamination effect which causes increases in temperature variance. Predictions for C_T ² based on surface flux scaling agree within 20%, except for near neutral and large unstable conditions where disagreement can be attributed to measurement problems.     

海拉尔盆地基底晚古生代adakite的发现及其地质意义

海拉尔盆地的前中生代基底隶属中亚造山带东段的兴蒙造山带。 在盆地基底地层中发现了具有adakite成分特征的粗面安山岩、英安岩和闪长玢岩。 这些火成岩与晚古生代沉积地层交互或伴生, 共同构成晚中生代裂陷盆地的基底。 地球化学研究表明, 这些火成岩基本上属于高钾钙碱性和准铝质岩石系列, 具有高SiO₂和Al₂O₃含量, 高Sr、Sr/Y和La/Yb值, 富集轻稀土(LREE), 亏损重稀土(HREE)、Y和高场强元素(HFSE),Eu表现弱的负异常或轻微的正异常, 相容元素Mg、Cr和Ni含量低, 这些特征与增厚下地壳部分熔融成因的adakite非常相似, 而明显不同于典型的由俯冲洋壳熔融形成的adakite。 样品的(⁸⁷Sr/⁸⁶Sr)_i值基本一致,为0.7041, (¹⁴³Nd/¹⁴⁴Nd)_i值为0.51243~0.51247, ε_Nd (t)为正值(+3.7~+4.5), 显示其岩浆源区可能源于弱亏损地幔, 或亏损地幔受到地壳物质混染。 本文认为海拉尔地区晚古生代adakite型岩浆很可能是由当时新底侵的玄武质下地壳在角闪岩相向榴辉岩相过度或榴辉岩相条件下部分熔融形成。 这些adakite岩石的出现反映了兴蒙造山带晚古生代受到了古亚洲洋的俯冲消减引起的强烈的地幔玄武质岩浆底侵作用, 并由此导致地壳垂向上显著的增生加厚过程。     

Cypermethrin induces glutathione S-transferase activity in the shore crab,Carcinus maenas

Cypermethrin is a synthetic pyrethroid that is particularly toxic to crustacea. It is therefore applied as a chemotherapeutant in the salmonid aquaculture industry for the treatment of sea lice infestations. After use, cypermethrin is released directly into the marine environment, to be diluted by fresh seawater. The shore crab, Carcinus maenas is found in the vicinity of fish farms, and may come into contact with released cypermethrin. The detoxification enzyme, glutathione S-transferase (GST) has been implicated in cypermethrin metabolism in terrestrial arthropods, but this has not yet been demonstrated in crustacea. In this paper we investigate the response of GST activity in Carcinus to cypermethrin exposure, and also the time course of the induction process. GST activity is significantly increased in Carcinus exposed to nominal concentrations of 50 and 500 ng/l of water-borne cypermethrin. Carcinus demonstrate a significant elevation in GST activity following intra-cephalothoracic injection with 10 ng of cypermethrin. GST activity returns to basal levels after 36 h. The potential application of GST activity in Carcinus as a biomarker of cypermethrin exposure is discussed.     

Alkoxyquinoline O-dealkylation: A new fluorimetric assay for hydrocarbon-induced cytochrome P450 in fish

The O-dealkylation of a new series of substrates, the alkoxyquinolines, provides a new easy fluorimetric assay for measuring the induction of cytochrome P450 by polycyclic aromatic hydrocarbons and drilling mud oil in fish. Expression of the results as a ratio between the inducible butyloxyquinoline O-dealkylation (BuQOD) activity and the non-inducible benzyloxyquinoline O-dealkylation (BeQOD) activity (i.e. the ‘BuQOD:-BeQOD quotient’) maximises the degree of induction measured and minimises the degree of inter-animal variation.     

Measurements of the rate of dissipation of turbulent kinetic energy, ɛ, over the ocean

In a series of cruises during the last three years, the Naval Postgraduate School Environmental Physics Group has made more than 1000 shipboard measurements of the rate of dissipation of turbulent kinetic energy, , using inertial subrange (high frequency) techniques. Utilizing the bulk-aerodynamic method to obtain the relevant Monin-Obukhov surface layer scaling parameters, the overwater dimensionless dissipation function 321-01, has been examined with unprecedented statistical certainty. The results agree well with those of Wyngaard and Coté (1971) for the stable case but they agree more closely with the parameterization of McBean and Elliott (1975) for unstable conditions. Drag coefficients computed from the data are in good agreement with the curve given by Garratt (1977).