Nutrient enrichments and phytoplankton growth in the surface waters of the Louisiana Bight

Nitrate concentrations have increased twofold in the Mississippi River during the past three decades. The increased nitrogen loading to the Louisiana shelf has been postulated as a factor leading to eutrophication and the subsequent development of hypoxia west of the Mississippi River delta. While ratios of nitrogen:phosphorus and nitrogen:silica are relatively high in surface waters on the western Louisiana shelf, nitrogen has been posed as the ‘limiting’ nutrient in this region. Bioassays were performed with nutrient additions to surface waters collected from the Louisiana shelf to examine the potential for specific nutrient limitation. Experiments were conducted in March and September 1991, and May 1992. The growth responses of natural and cultured phytoplankton populations were determined by measuring the time course of in vivo and 3-(3,4 dichlorophenyl)-1, 1-dimethylurea (DCMU)-induced fluorescence, as well as initial and final chlorophylla concentrations. The results suggest that phosphate and silicate potentially limit phytoplankton growth during the winter-spring, particularly at low salinities. In late summer, in contrast, nitrogen limitation may be prominent at higher salinities.     

Estuarine macrobenthos in Calcasieu Lake,Louisiana: Community and trophic structure

Macrobenthic assemblages in Calcasieu Lake estuary (Louisiana) were sampled at 11 sites from October 1983 through November 1985. The sites were numerically dominated by subsurface-deposit feeders, consisting mostly of polychaetes. Greater densities of macrofauna were collected at the northern (upper) stations of the lake than were collected in West Cove or the southern stations. Abundances of polychaetes, oligochaetes, and amphipods at the upper lake stations accounted for most of the differences among stations. The numerical dominance by detritivores (97% of the fauna) and lack of strong sediment or salinity gradients across the estuary, resulted in an absence of temporal pattern in trophic structure of the macrofauna.     

Prosperity and the New Economy in Canada’s major city regions

Canada’s three large city regions—Montréal, Toronto and Vancouver—have been relatively successful in retaining their Manufacturing bases, while at the same time adding substantial numbers of New Economy job opportunities. Deindustrialization appears to have occurred primarily in the Montréal CMA (Census Metropolitan Area) and in some smaller communities where motor vehicle manufacturing was significant. Growth in New Economy jobs has occurred in the larger CMAs; the smaller urban areas have had little success in attracting these jobs. For the most part, these trends appear to be path dependent: prosperous communities with substantial proportions of New Economy jobs are likely to remain prosperous and to attract more such jobs. The lack of significant correlation between Economic Health and the presence of immigrants, same sex couples, performing and visual artists suggests that local economic development strategies based on these factors may have limited success.     

Quantification of adamantane in organic media via infrared attenuated total reflection spectroscopy

In the present study, the quantitative determination of the diamondoid compound adamantane in organic solvents via infrared attenuated total reflection (IR-ATR) spectroscopy at unmodified waveguide surfaces was established. Limits of detection (LOD) and quantification (LOQ) of adamantane in dichloromethane, hexane and carbon tetrachloride were determined. Quantitative IR-ATR measurements additionally facilitated the determination of adamantane solubility limit in dichloromethane, hexane and carbon tetrachloride. The developed analytical strategy further enabled the successful detection and quantification of adamantane in crude oil matrices. Consequently, IR-ATR spectroscopy provides a promising strategy for on ship and in situ diamondoid analysis in harsh real world environments.     

Die Bodenstruktur des Indischen Ozeans und dessen Geschichte

Zusammenfassung Grundzüge des Bodenreliefs und geophysikalisch-geotektonische Kenntnisse im Bereiche des Indischen Ozeans ermöglichen es, Art und Reihenfolge seiner Entwicklung zu skizzieren. Eine erste, parallel den Breitengraden während der Alttrias-Zeit aufgerissene Tiefspaltenzone unter dem Riesenkontinent Gondwanaland trennte die Antarktis von Südamerika-Afrika-Indien-Australien. Durch Querdehnung der Spalten drangen gewaltige basaltische Magmamassen empor. Sie erweiterten wie in Island die aufklaffenden Brüche und drängten die Kontinente auseinander, so daß die vier genannten Großschollen bis über die heutige Lage des 50.° Süd nordwärts verlagert wurden. Hinter ihnen blieb ihre alte, basische und vulkanisch tätige Unterlage zurück als erster Südteil des Indischen Neu-Ozeans. Unregelmäßige Hemmungen bei der Norddrift der Teilschollen dürften zwischen diesen méridionale Blattspalten erzwungen haben.Deren östlichste trennte zunächst jungtriassisch Australien ab von Indien und den anderen westlichen Kontinentalschollen. Diese méridionale Blattspalte wurde zu einer mittelozeanischen Schwelle und drängte einerseits Australien an seinen Platz gegen Osten, andererseits Indien zusammen mit Lemurien gegen Westen. Dann riß die Carlsberg-Mittelindische Schwelle auf und rückte Lemurien westwärts, Indien ostwärts bis zum 90.° Ost. Von der Mittelkreidezeit an wurde die Indische Scholle gegen Norden bis vor den Himalaya verlagert. Sie kam in der Oberkreidezeit an.Dies bewirkte keine neue Mittelozeanische Spaltenschwelle mehr. Vielmehr hatte sich eine regional das gesamte Untergrundsgebiet des Indischen Ozeans erfassende Unterströmung gegen Norden entwickelt. Sie floß unter Himalaya und Tibet noch weiter gegen N und E, wo sie das bekannte Dach der Erde im Tertiär emporstemmte.Die möglichen Begründungen enthält der nachfolgende Text.

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It is possible to reconstruct the nature and sequence of development of the Indian Ocean through knowledge of the topology and through geophysical-geotectonic research.The first deep fault zone situated under the great continent Gondwanaland, went parallel to the latitude during the lower Triassic Period and separated the Antarctic from South America, Africa, India and Australia. The basaltic magma was pushed up through the transverse expansion of the crevices. The opened cracks were widened like in Iceland and presed the continents apart. In this way the 4 great continents mentioned above, were pushed northwards farther than the 50° lat. S of today. Behind them remained the old, basic, and volcanicaly active foundation as the first southern floor of the Indian Ocean. Irregular retardations during the northern drift of parts of the continents probably had caused meridial fissures (Blatt-Spalten).The eastern most part of the fissures first divided in the Upper Triassic Period Australia from India and the other western continental blocks. These meridial fissures grew to a middle ocean rise and pushed on one side Australia to the east, and on the other side India together with Lemur to the west.The Carlsberg-Middle-Ocean Rise then shoved Lemur westward and India eastward to 90° E. Beginning in the Middle Cretaceous Period, the Indian block moved to the north and reached the Himalayas in the Upper Cretaceous Period. This did not cause any new middle ocean Spaltenschwelle. On the contrary, in the underground region of the Indian Ocean an underflow to the north had developed. It flowed under the Himalaya and Tibet and even more to the north and east where the famous roof of the Earth originated.The possible reasons are given in the following text.

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Résumé Le relief du fond de la mer et des faits géophysicaux et géotectoniques dans la région de l'Océan Indien rendent possible d'esquisser la façon de laquelle cet Océan s'est formé. Une zone primaire de fissures profondes formée pendant le Trias inférieur et située parallèle aux degrés de latitude au-dessous du continent gigantesque Gondwanaland séparait la région antarctique d'une part et l'Amérique du Sud, l'Afrique, les Indes et l'Australie d'autre part. A la suite d'une expansion de fissures d'énormes masses basaltiques se levèrent. Celles-ci élargirent les fentes, comme en Islande, et renforcèrent la séparation des continents. C'est pourquoi les quatre boucliers cités furent poussés au-delà de 50° degré de latitude vers le Nord. Leur soubassement basique et volcanique restait à sa place et formait la première partie méridionale du nouvel Océan Indien. Des obstacles irréguliers freinèrent le mouvement vers le Nord des divers boucliers, ce qui peut avoir causé les décrochements parallèles aux méridians.Le décrochement le plus oriental séparait d'abord, au Trias supérieur, l'Australie des Indes et des autres boucliers continentaux à l'Ouest. Le linéament décroché se transforma en un seuil au milieu de l'Océan et poussa d'une part l'Australie vers sa place orientale, d'autre part les Indes avec la Lémurie vers l'Ouest. Puis le linéament Carlsberg au milieu de l'Océan Indien s'ouvrit et transporta la Lémurie vers l'Ouest, les Indes vers l'Est. Dès le Crétacé moyen le bouclier indien a été transporté vers le Nord jusqu'au Himalaya. Il y arriva pendant le Crétacé supérieur.Ceci ne causa plus une nouvelle élévation au milieu de l'Océan. Plutôt il s'était produit une subfluence générale dirigée vers le Nord et emportant le soussol entier de l'Océan Indien. Cette subfluence se prolongea au-dessous de l'Himalaya et du Tibet vers le NE, soulevant au Tertiaire le célèbre Toit de la Terre.Dans la suite les raisons de cette opinion seront exposées.

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近期博斯腾湖水位变化及其原因分析

新疆博斯腾湖1987年以来湖泊水位的变化(上升)与主要补给河流开都河径流量的变化有直接关系, 而这与发源于天山中段降水和高山冰雪融水的河流, 受到气候变化影响很大有关. 全球变化研究结果显示, 中亚干旱区是全球温度上升幅度较大的地区. 当地的气象资料表明, 过去20 a年平均温度明显升高的趋势, 对水资源储量和补给来源影响深远.     

Volatiles in glasses from Mauna Loa Volcano,Hawai'i: implications for magma degassing and contamination,and growth of Hawaiian volcanoes

Glasses from Mauna Loa pillow basalts, recent subaerial vents, and inclusions in olivine were analyzed for S, Cl, F, and major elements by electron microprobe. Select submarine glasses were also analyzed for H₂O and CO₂ by infrared spectroscopy. The compositional variation of these tholeiitic glasses is dominantly controlled by crystal fractionation and they indicate quenching temperatures of 1,115-1,196 °C. Submarine rift zone glasses have higher volatile abundances (except F) than nearly all other submarine and subaerial glasses with the maximum concentrations increasing with water depth. The overwhelming dominance of degassed glasses on the submarine flanks of Mauna Loa implies that much of volcano's recent submarine growth involved subaerially erupted lava that reached great water depths (up to 3.1 km) via lava tubes. Anomalously high F and Cl in some submarine glasses and glass inclusions indicate contamination possibly by fumarolic deposits in ephemeral rift zone magma chambers. The relatively high CO₂ but variable H₂O/K₂O and S/K₂O in some submarine rift zone glasses indicates pre-eruptive mixing between degassed and undegassed magma within Mauna Loa's rift system. Volatile compositions for Mauna Loa magmas are similar to other active Hawaiian volcanoes in S and F, but are less Cl-rich than Ll'ihi glasses. However, Cl/K2O ratios are similar. Mauna Loa and Ll'ihi magmas have comparable, but lower H₂O than those from Kilauea. Thus, Kilauea's source may be more H₂O-rich. The dissimilar volatile distribution in glasses from active Hawaiian volcanoes is inconsistent with predictions for a simple, concentrically zoned plume model.