Colloidally separated samples from Allende residues: Noble gases,carbon and an ESCA-study

A non-colloidal fraction separated by physical means from an $\text{HF}\text{HCl}$-resistant residue of the Allende carbonaceous meteorite exhibits a ratio of isotopically “normal” (Q-type) xenon to “anomalous” xenon (X-type) that is ~4 times larger than usually observed. Coincidentally this fraction contains carbon that is isotopically heavier by ~10%. than bulk Allende residue samples. ESCA analyses of companion colloidal separates show that the major portion of the S contained in our $\text{HF}\text{HCl}$-residues is elemental rather than a sulfide. They also confirm earlier observations that no elementally distinct surface coating is present, in accord with the absence of a surface-sited sulfur-bearing gas carrier, and that the oxygen content is increased after etching with nitric acid. For these separates noble gas data coupled with the ESCA data for nitrogen and the isotopic data for carbon point to the existence of heterogeneities among the noble gas-, carbon- and nitrogen-bearing phases and, thus, preservation of discrete components from the variety of source regions (or production mechanisms, or both) sampled by the Allende parent body. In sharp contrast to the success of physical and chemical methods in yielding samples in which one of the major noble gas components predominates to an extraordinary degree over the other, carbon isotopic compositions that have been inferred for the respective carrier phases in these same samples are strongly contradictory. Mass and isotope balance considerations lead us to conclude that a major fraction of the carbonaceous matter in Allende is noble-gas-poor, a result that could be confirmed by direct isolation of a sample, the carbon in which is dominated by this variety; and for that reason no simple relationship is discernable yet between observed isotopic compositions and either major noble gas component. Similar ambiguities may exist for nitrogen. The possible relationship between carbon-rich phases in ureilites and carbonaceous chondrites is considered.     

Effects of turbidity caused by nutrient loading on benthic dynamics

The benthic response to nutrient loading of the water column was determined in the transition from early to mid-summer in a semi-enclosed, shallow estuarine ecosystem of the Baltic Sea. The procedure involved the inoculation of an in situ mesocosm with nitrogen and phosphorus to induce hypertrophic conditions, and comparison of this treated compartment with an untreated control. Sediment activity was assessed as oxygen turn-over, and measured in the laboratory with a simulated in situ polarographic flow-through method. Nutrient addition induced the development of pelagic organisms, particularly phytoplankton and protozoa, which resulted in turbidity within the water column. The latter appeared to depress benthic primary productivity. On the other hand, the greater organic matter load, upon sedimenting, caused increased biological respiration of the sediment. Chemical oxygen demand was unaffected by the increased organic matter input.     

Zur Vertikalwanderung planktischer Copepoden im Bodenseee-Obersee

In completion of long-term investigations on the annual cycles of planktonic crustaceans in Lake Constance a number of day-night samples were taken. The results are presented in regard to the amplitudes of vertical movements for some copepods, especially the different instars. The numbers in the net hauls show a coarse but clear picture of these migrations. The role of diurnal vertical migration for the release of diapause inCyclops vicinus is discussed.      

Die Entwicklung und Männchenbildung derDaphnia-Population im Bodensee-Obersee 1956–1980

Besides the old-settledDaphnia hyalina a ‘galeata’-type ofDaphnia immigrated into Lake Constance (Upper Lake) in the beginning of the fifties. Since this time a great number of phenotypes with a high degree of morphological variations was registrated. Since about 1970 a smallDaphnia type became more and more numerous, especially in the eastern part of the lake. An exact determination is not yet possible. In 1972 an extreme maximum ofDaphnia males was found. The share of males increased from 3 to 4% of the population to 30% in autumn 1972. In the following years the percentage decreased again to the formerly observed 3–4%. The relationship to the phytoplankton biomass is discussed.     

Majorite formation from enstatite by experimental shock-loading

Majorite has been observed for the first time after experimental shock-loading of enstatite (Bamle, Norway). The identification of this high pressure garnet has been carried out by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction experiments, majorite formation was indicated by these techniques for the pressure range between ca. 35 and 50 GPa. This also proves formation of majorite by impact metamorphosis in the Coorara meteorite as well as terrestrial formation of that phase by the same process.     

Chemical fractionation of transition elements in Pacific pelagic sediments

Partitioning of transition elements in Pacific pelagic sediments (35 samples) was performed by sequential chemical leaching with barium chloride/triethanolamine (easily extractable fraction), acidic cation exchange resin (carbonate phases), and hydroxylamine hydrochloride and dilute hydrochloric acid solutions (hydrous oxides). Residual metal percentages are highest in red-brown clays and siliceous ooze, intermediate in calcareous materials and low in micronodules (2 samples, > 125 μm): residual metal contents seem to be controlled predominantly by the rate of admixture of volcanoclastic materials. At higher bulk metal concentrations, the non-residual fractions of Mn, Cu, Ni and Zn generally increase both in red-brown pelagic clays and in siliceous ooze. Mn, Ni, and Co concentrations are mainly associated with the easily reducible fraction (0.1 M NH₂OH·HCl), whereas Fe, Cu, and Zn exhibit higher percentages in the hydrochloric acid soluble fractions (0.3 M HCl); Zn and Cu are associated to some extent with the carbonate phase, copper with the easily extractable fraction.