Long-term chemical effects of petroleum in south Louisiana wetlands—I. Organic carbon in sediments and waters

The chemical effects of chronic petroleum input into a shallow water marsh were examined by measuring hydrocarbon levels and dissolved organic carbon content of sediments associated with two active oil fields in south Louisiana. Annual levels of total organic carbon in the surface waters of the oil fields were higher by 1 mg C/l. in the salt marsh and 5 mg C/l. in the fresh marsh than the respective controlsites. Average dissolved organic carbon concentrations in the interstitial waters of cores taken within the oil field environments were 105% higher than the control in the salt marsh and 43% higher than the control in the fresh marsh. Significantly lower ratios of C₁₇ to pristane occurred in both oil field sediments; however, average odd-even predominance values were not indicative of petroleum contaminated sediments. The results indicate that microbial processes are responsible for dissolution of petroleum into dissolved organic carbon and that dissolved organic carbon concentrations may be a more significant measure of chronic petroleum input than hydrocarbon distribution.     

The influence of sea waves on the wind profile

From wind profile and wave measurements performed during the JONSWAP II experiment, relations between the dimensionless profile slope and the significant wave height are derived. It is shown that the wind profile is distorted by the waves especially in the vicinity of the water surface. The wave influence on the profile seems to be restricted to heights below about three wave heights. Above this level, the dimensionless profile slope is an approximately constant value corresponding to a drag coefficient of about 1.15 × 10^–3.     

A review of applications of microwave radiometry to oceanography

The thermal microwave radiation from the ocean surface as seen from space is a function of the surface temperature and wind speed and is modified by liquid water and water vapor in the intervening atmosphere. Further, if the ocean surface is frozen, the emissivity is drastically increased and the effect of the intervening atmosphere is generally negligible. The emissivity of first-year ice is somewhat larger than that of multi-year ice.The data from the Electrically Scanning Microwave Radiometers (ESMR's) on the Nimbus-5 and —6 satellites operating at wavelengths of 1.55 cm and 8 mm, respectively, can be interpreted in terms of rain rate, ice coverage and first-year versus multi-year ice determination. The rain-rate data are being used to establish a climatology of rainfall over the oceans. The ice data are being used by the United States Navy in support of international scientific efforts in the Antactic region. Both ice and rain data sets have been generated for the Global Atmospheric Research Project Data Systems Test.It is possible, by making multifrequency measurements, to separate the surface and atmospheric effects and to make useful measurements of sea surface temperature, surface wind speed, and atmospheric parameters along with improved measurements of rain and ice.     

Paläoklimatische Information im Isotopengehalt14C-datierter Saharawässer: Kontinentaleffekt in D und18O

Zusammenfassung In den¹⁴C-Altern der Saharawässer spiegelt sich die wechselnde Abfolge von Feucht- und Trockenphasen während des späten Pleistozäns und Holozäns wider. Außerdem zeigt sich ein West-Ost-Gefälle in ihrem D- und¹⁸O-Gehalt, das als Kontinentaleffekt im Grundwasser gedeutet wird. Dieser Kontinentaleffekt setzt voraus, daß das nordafrikanische Klimageschehen vergangener Feuchtphasen von der Westdrift bestimmt wurde, die regenbringende atlantische Luftmassen weit ins Saharainnere getrieben hat. Ein einfaches mathematisches Modell, das den Kontinentaleffekt durch eine Rayleigh-Kondensation beschreibt, ergibt die beste Anpassung an die Meßwerte, wenn für die Sahara (ähnlich wie heute in Europa) ein West-Ost-Gefälle in den Paläo-Winterniederschlagsmengen von –30% pro 1000 km angenommen wird. Unter der Annahme ehemaliger Winterniederschläge (Sept.-März) von 600 mm (entspricht Lissabon heute) für das Gebiet an der nordafrikanischen Atlantikküste ergibt diese Modellrechnung z. B. 250 mm für die Paläo-Winterniederschläge im Gebiet des Murzuk-Beckens.

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The¹⁴C-age distribution of Saharian groundwaters shows the alternating sequence of humid and arid periods in the late Pleistocene and Holocene. The observed west-east decrease of the D- and¹⁸O-content of the Sahara waters is interpreted to be the Continental Effect in rain and groundwater. The paleoclimatic situation during ground-water formation therefore was controlled by the western drift carrying wet Atlantic air masses across the Sahara. The best fit of a simple Rayleigh condensation model of the continental effect to the experimental data is obtained with a west-east decrease of the Saharian paleo-winter precipitation of –30% per 1000 km (similar to the one in Europe today). With an annual winter precipitation rate (Sept.-March) of 600 mm (corresponding to the one of Lisboa today) for the Northafrican coastal area at the Atlantic Ocean a previous winter precipitation rate of 250 mm is obtained for the Murzuq Basin.

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Résumé Une succession de périodes humides et arides à la fin du Pléistocène et à l'Holocène se réflète dans la distribution des âges¹⁴C d'eaux souterraines du Sahara. Les teneurs en D et¹⁸O diminuent d'Ouest en Est, ce qui est interprété comme un effet continental dans l'eau souterraine. Celui-ci signifie que la climatologie des phases pluviales passées, dans l'Afrique du Nord, était déterminée par des vents d'Ouest qui apportaient des masses d'air atlantique humide à l'intérieur du Sahara. Un modèle mathématique simple décrivant l'effet continental par une condensation du type Rayleigh, reproduit avec la meilleure conformité les valeurs expérimentales, pour autant qu'on admette que les pluies hivernales au Sahara diminuaient anciennement d'Ouest en Est de 30% par 1000 km (comme à présent en Europe). En supposant qu'autrefois la quantité de pluie hivernale, de septembre à mars à la côte atlantique de l'Afrique du Nord était de 600 mm (comme aujourd'hui à Lisbonne), on obtient à l'aide de ce modèle une précipitation hivernale ancienne de 250 mm dans le bassin du Mourzouk.

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, ¹⁴C, . , ¹⁸O, , . , , , , . , Rayleigh, — , — — 30 % 1000 . , - , . . , 600 , — —, 250 .

     

Die Anomalien der Schwere am Südwest-Rand des Bayerischen Waldes und ihre Interpretation

Zusammenfassung Zur Untersuchung der Störungssysteme, die im Raum Regensburg—Passau das Kristallin-Gebiet des Vorderen Bayerischen Waldes gegen die Sedimente des Vorlands begrenzen, wurden entlang von neun Profilen senkrecht zum Streichen der tektonischen Linien (Donau-Randbruch, Pockinger Abbruch, Keilberg-Störung) gravimetrische Messungen durchgeführt. Die Gesamtlänge der Profile beträgt 173 km, bei einer Gesamtzahl von 1985 Gravimeter-Meßpunkten, also einem mittleren Punktabstand von 87 m. Für alle Punkte wurden Freiluft- und Bouguer-Anomalie berechnet. Zur Interpretation der Schwere-Anomalien wurden Modelle von zweidimensionalen Störkörpern entworfen, deren berechnete Schwerestörung mit der gemessenen gut übereinstimmt. Dabei wurden Bohrergebnisse mit berücksichtigt und als Randwerte einbezogen.Der Zunahme des Schwere-Unterschieds zwischen Kristallin und Vorland von Nordwesten nach Südosten entspricht dabei eine Zunahme der Sedimentmächtigkeit von etwa 500 m bei Regensburg auf etwa 1600 m südlich von Passau. Die Modellrechnungen ergaben außerdem oberflächennahes Kristallin im südöstlichen Drittel des Untersuchungsgebietes, das sich noch mehrere Kilometer südlich des Anstehenden unter nur geringer Sedimentbedeckung (unter 150 m) befindet. Eindeutig konnte entschieden werden, daß die Südgrenze des Vorderen Bayerischen Waldes als tektonische Abschiebung, meist in Form eines Staffelbruchs, ausgebildet ist und keineswegs Kristallin auf die Sedimente aufgeschoben ist. Südlich von Passau konnte aus den Schwereanomalien eine höhere Dichte des Kristallins abgeleitet werden, die durch dort vorkommenden dichteren Gneis erklärt wird. Magnetische Anomalien in unmittelbarem Zusammenhang mit den tektonischen Störungen konnten nicht beobachtet werden. Obwohl seismische Ereignisse nicht registriert wurden, gibt es einige Hinweise, daß die Bewegungen am Donau-Randbruch noch andauern.

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The marginal faults separating the crystalline region of the Bavarian Forest (Bohemian Massif) in the area between Regensburg and Passau (Southern Germany) from the sediments of the Molasse basin to the south were investigated with gravity measurements along nine profiles perpendicular to the strike of the faults. The total length of the profiles is 173 km with a total number of 1985 gravity points (mean distance 87 m). Free-air (Faye-) and Bouguer anomalies of all stations were calculated. Models of two-dimensional bodies using data from drillings were developed. The increase of the intensity of the gravity anomalies from NW to SE corresponds to an increase of the thickness of the sediments from about 500 m near Regensburg to about 1600 m to the south of Passau. The model calculations moreover showed that the crystalline basement in the south-eastern part of the area extends several kilometers to the south of the outcrops beneath a thin sedimentary layer of less than 150 m. It was possible to show that normal type faults dominate, usually in the form of antithetical steps. An upthrust of the Bavarian Forest onto the Molasse basin could be excluded. South of Passau the gravity anomalies support a higher density of the crystalline rocks which is explained by the denser gneiss outcroping locally there. It was impossible to observe magnetic anomalies directly associated with the faults. Although seismic events could not be registered, there are indications of tectonical movements still continuing at present.

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Résumé Les failles marginales qui séparent dans la région de Regensburg—Passau (Allemagne du Sud) la zone cristalline de la ForÊt Bavaroise (Massif Bohémien) des sédiments du bassin molassique au Sud on été étudiées à l'aide de mesures gravimétriques suivant neuf profils perpendiculaires à la direction des failles. La longueur totale des profils est de 173 km avec 1985 points gravimétriques au total (distance moyenne 87 m). Des anomalies à l'air libre (de Faye) et de Bouguer on été calculées pour toutes les stations. Pour interpréter les anomalies de la gravité, on a développé des modèles de corps à deux dimensions dont les anomalies calculées s'accordent bien avec les anomalies mesurées. Dans ces modèles on a utilisé et intégré des résultats des forages comme valeurs marginales. L'augmentation de l'intensité des anomalies de la gravité du Nord-Ouest vers le Sud-Est correspond à une augmentation d'épaisseur des sédiments d'environ 500 m près de la ville de Regensburg, à environ 1600 m au Sud de la ville de Passau. De plus, les calculs sur modèle on fait apparaÎtre que dans la partie Sud-Est de la région étudiée, le soubassement cristallin couvert d'une mince couche sédimentaire de moins de 150 m se continue de plusieurs kilomètres au Sud des affleurements. On a pu démontrer que des failles antithétiques sont prédominantes, le plus souvent sous forme d'une faille en escalier. Un chevauchement de la ForÊt Bavaroise sur le bassin molassique peut Être exclu. Au Sud de Passau, il a été possible de déduire des anomalies de la gravité une densité plus élevée du cristallin, ce qui s'explique par la densité plus forte des gneiss de cette région. On n'a pas observé d'anomalies magnétiques en rapport direct avec des failles. Bien que des événements sismiques n'aient pas été enregistrés, il y a quelques indicies que les mouvements tectoniques perdurent le long de faille du Danube.

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, , 9 ( , Pockingcr Keilberg). 175 1985 . 87 . . , . . 500 1600 . , — 150 . , , , , . , , , . . , . .

     

Mean bulk densities of samples of dry atmospheric aerosol particles: A summary of measured data

Mean bulk densities of various samples of dry atmospheric aerosol particles sampled at different sites and during different seasons and weather situations range between 1.8 and more than 3 gm cm³.     

“Pandora box” — Matrix in the calculus of observations

Summary If the condition R(A)=k(n), whereA is the design matrix of the type n × k and k the number of parameters to be determined, is not satisfied, or if the covariance matrixH is singular, it is possible to determine the adjusted value of the unbiased estimable function of the parameters f(), its dispersion D( (x)) and ² as the unbiased estimate of the value of ² by means of an arbitrary g-inversion of the matrix . The matrix , because of its remarkable properties, is called the Pandora Box matrix. The paper gives the proofs of these properties and the manner in which they can be employed in the calculus of observations.     

Identity of the characteristics of electrodynamic seismographs with non-standard periods of seismometers and galvanometers

Summary The maximum changes of magnification were determined for electrodynamic seismographs with standard characteristics and for some experimental long-period seismographs, the constants of which are given in Tab. 1, when the period of the seismometer or galvanometer has a deviation of not more than 5% from the standard value. Under the assumption of control of the other constants of the seismograph, identical amplitude and phase responses with a small change of the absolute magnification of the seismograph may be achieved with characteristicsAII ( ² >0.2), AIV ( ² 0.4), B ( ² >0.3) Nos28, 32 and33. This deviation can also be compensated by adjusting the optical distance. The procedure of adjusting the identical characteristics is suitable for systems with which an accurate setting of the period is difficult and for systems with an uncontrollable period, provided their values are within the limits of allowed deviations from the standard constants.     

Amplitudes of long-period PcP and the core-mantle boundary

The amplitudes of the core reflection PcP are sensitive to the wave velocities and densities in the neighborhood of the core-mantle boundary (CMB). We study the amplitude ratio of the long-period phases PcP and P from two South American deep-focus earthquakes with favorable fault-plane solution, depth and magnitude, as recorded by WWNSS and CSN stations in North America.Comparison is made with long-period PcP/P amplitude ratios, derived from theoretical seismograms for a variety of CMB models. Models from previous studies, which were mainly derived from short-period PcP observations and which are characterized by discrete layers above the CMB, are almost all inconsistent with the long-period data. The data also discriminate against low nonzero S velocities below the CMB. Simple first-order-discontinuity models of the CMB, for instance according to the Jeffreys-Bullen earth model or according to recent models based mainly on free oscillations, explain the data reasonably well.Model improvements are attempted by varying the P-velocity gradient above the CMB. The best amplitude fit is obtained for a rather strong decrease in P velocity with depth in this zone which, however, gives no acceptable traveltime fit for PcP. The scatter in body-wave amplitudes is considerable even for long-period waves and may prevent the correct assessment of that part of the amplitude variation of a phase with distance that is due to the variation of velocities and densities with depth alone.