The control of the production process of phytoplankton by the physical structure of the aquatic environment with special reference to its optical properties

This tutorial was designed for nonbiologists requiring an introduction to the nature and general timescales of phytoplankton responses to physical forcing in aquatic environments. As such, an effort was made to highlight biological markers which might assist in identifying, measuring and/or validating physical processes controlling the variability in the distribution, abundance, composition and activity of phytoplankton communities. Given the recent advances in environmental optics and remote sensing capabilities, a special emphasis was placed on the nature and utility of phytoplankton optical properties in current bio-optical modelling efforts to predict temporal and spatial variability in phytoplankton productivity and growth.     

临界转换的早期预警信号

从生态系统到金融市场和气候在内的很多复杂动力系统,都会有临界点,在这样的点上系统可能会发生突变,从而演变到一个对立的动力模式上。在这样的临界点到达之前对其进行预测极为困难,但是现在,不同科学领域的研究工作表明,普遍性的早期预警信号有迹可循。对一系列不同类型的系统来说,这些信号会指示是否正在趋近一个临界阈值。     

Vertikale und zeitliche Verteilung der Leitfähigkeit in einem eutrophen Gewässer während der Sommerstagnation

Summary Data are given of the vertical distribution of temperature, conductivity and alkalinity of an eutrophic lake (Rotsee near Lucerne) measured at short intervals during the summer stratification. We were able to prove in a limited measure only the expected day's periodicity from the conductivity of the CO₂-assimilation of the phytoplankton. We found pronounced internal ‘seiches’ in the hypolimnion; their mathematical interpretation is given only in the order of size.Rodhe's diagram andNümann's method make it possible to determine quantitative relations; from the chemical point of view the lake (depth 16,5 m) shows a four-layered type during the summer.      

Entstehung und Alter der Oberharzer Gänge

Ohne Zusammenfassung     

Protokoll der wissenschaftlichen Sitzung am 4. und 5. Januar 1937

Ohne Zusammenfassung     

Eine Induktions-Impulsmethode für den Nachweis des Erdöls

Zusammenfassung Es wird eine Induktionsimpulsmethode beschrieben, welche sich auf die Messung dielektrischer Dispersionsphänomene gründet, und welche einen direkten Nachweis des Petroleums auf Tiefen von über 2000 m ermöglicht. Durch Variation der Anfachungsbedingungen kann man selektive Reaktionswirkungen erzielen.

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Summary An induction pulse method is described, based upon the measurement of a dielectric dispersion phenomenon. This method opens the possibility of a direct and selective reaction of the petroleum at a depth of more than 6000 feet. Hereby the selective reaction is based upon the variation of the exciting conditions.

     

Assessment of the interstellar processes leading to deuterium enrichment in meteoritic organics

Abstract— The presence of isotopic anomalies is the most unequivocal demonstration that meteoritic material contains circumstellar or interstellar components. In the case of organic compounds in meteorites and interplanetary dust particles (IDPs), the most useful isotopic tracer has been deuterium (D). We discuss four processes that are expected to lead to D enrichment in interstellar materials and describe how their unique characteristics can be used to assess their relative importance for the organics in meteorites. These enrichment processes are low‐temperature gas phase ion‐molecule reactions, low‐temperature gas‐grain reactions, gas phase unimolecular photodissociation, and ultraviolet photolysis in D‐enriched ice mantles. Each of these processes is expected to be associated with distinct regiochemical signatures (D placement on the product molecules, correlation with specific chemical functionalities, etc.), especially in the molecular population of polycyclic aromatic hydrocarbons (PAHs). We describe these differences and discuss how they may be used to delineate the various interstellar processes that may have contributed to meteoritic D enrichments. We also briefly discuss how these processes may affect the isotopic distributions in C, O, and N in the same compounds.     

Near-infrared laboratory spectra of solid H2O/CO2 and CH3OH/CO2 ice mixtures

We present near-IR spectra of solid CO₂ in H₂O and CH₃OH, and find they are significantly different from that of pure solid CO₂. Peaks not present in either pure H₂O or pure CO₂ spectra become evident when the two are mixed. First, the putative theoretically forbidden CO₂ (2ν₃) overtone near 2.134 μm (4685 cm⁻¹), that is absent from our spectrum of pure solid CO₂, is prominent in the spectra of H₂O/CO₂=5 and 25 mixtures. Second, a 2.74-μm (3650 cm⁻¹) dangling OH feature of H₂O (and a potentially related peak at 1.89 μm) appear in the spectra of CO₂-H₂O ice mixtures, but are probably not diagnostic of the presence of CO₂. Other CO₂ peaks display shifts in position and increased width because of intermolecular interactions with H₂O. Warming causes some peak positions and profiles in the spectrum of a H₂O/CO₂=5 mixture to take on the appearance of pure CO₂. Absolute strengths for absorptions of CO₂ in solid H₂O are estimated. Similar results are observed for CO₂ in solid CH₃OH. Since the CO₂ (2ν₃) overtone near 2.134 μm (4685 cm⁻¹) is not present in pure CO₂ but prominent in mixtures, it may be a good observational (spectral) indicator of whether solid CO₂ is a pure material or intimately mixed with other molecules. These observations may be applicable to Mars polar caps as well as outer Solar System bodies.