Effects of cold eddy on phytoplankton production and assemblages in Luzon strait bordering the South China Sea

The biochemical effects of a cold-core eddy that was shed from the Kuroshio Current at the Luzon Strait bordering the South China Sea (SCS) were studied in late spring, a relatively unproductive season in the SCS. The extent of the eddy was determined by time-series images of SeaWiFS ocean color, AVHRR sea surface temperature, and TOPEX/Jason-1 sea surface height anomaly. Nutrient budgets, nitrate-based new production, primary production, and phytoplankton assemblages were compared between the eddy and its surrounding Kuroshio and SCS waters. The enhanced productivity in the eddy was comparable to wintertime productivity in the SCS basin, which is supported by upwelled subsurface nitrate under the prevailing Northeastern Monsoon. There were more Synechococcus, pico-eucaryotes, and diatoms, but less Trichodesmium in the surface water inside the eddy than outside. Prochlorococcus and Richelia intracellularis showed no spatial differences. Water column-integrated primary production (IPP) inside the eddy was 2–3 times that outside the eddy in the SCS (1.09 vs. 0.59 g C m⁻²d⁻¹), as was nitrate-based new production (INP) (0.67 vs. 0.25 g C m⁻²d⁻¹). INP in the eddy was 6 times that in the Kuroshio (0.12 g C m⁻²d⁻¹). IPP and INP in the eddy were higher than the maximum production values ever measured in the SCS basin. Surface chlorophyll a concentration (0.40 mg m⁻³) in the eddy equaled the maximum concentration registered for the SCS basin and was higher than the wintertime average (0.29 ± 0.04 mg m⁻³). INP was 3.5 times as great and IPP was doubled in the eddy compared to the wintertime SCS basin. As cold core eddies form intermittently all year round as the Kuroshio invades the SCS, their effects on phytoplankton productivity and assemblages are likely to have important influences on the biogeochemical cycle of the region.     

Soilscape and land‐use evolution related to drift sand movements since the bronze age in Eastern Jutland,Denmark

Quarry faces several kilometers long in the Glesborg area in Denmark show that Bronze Age farmers used a sustainable land‐use system. Despite nutrient‐poor soils, the Glesborg area was under a rotation system in which cropland alternated with grassland. Soil fertility was improved by the addition of household waste and probably also by locally obtained inorganic fertilizer. The soil surface was very stable, and local drift sand movement was limited. Toward the end of the Bronze Age, the landscape changed dramatically with the arrival of overwhelming amounts of drift sand, and farmsteads were abandoned. Subsequent land use on these poor fine sandy soils was no longer capable of maintaining a stable soil surface, and frequent erosion/sedimentation events of more local importance took place. The post‐Bronze Age landscape may have been mainly a shifting mosaic of heathland with some temporary arable fields and deflation/accumulation areas. This landscape persisted up to about 200 years ago, when afforestation programs started. © 2007 Wiley Periodicals, Inc.     

Crystallization of loparite in alkaline fluid-magmatic systems (from experimental and mineralogical data)

We studied loparite-containing rocks (lujaurites, juvites, foyaite-juvites, etc.) sampled from a complex of differentiated rocks and, partly, from a complex of eudialytic lujaurites of the Lovozero alkaline massif. Zoned crystals of loparite (the zoning is due to variations in Ti, Nb, REE, Sr, and Th contents) were examined by microprobing. We also carried out experimental studies of loparite formation in complex silicate–salt systems including sodium carbonate, chloride, fluoride, or sulfate at 400–1200 °C and 1–2 kbar. They show that the composition of loparites depends on the physicochemical conditions of their formation (fluid composition) and that natural loparite can crystallize in a wide range of temperatures. The produced loparite crystals are zoned as a result of variations in Ti, Nb, La, Ce, Y, Ca, and Sr contents, which is probably related to the kinetic specifics of crystallization. Their zoning is similar to that of loparites of the Lovozero massif.     

Silver and silver microparticles of the Cretaceous-Paleogene boundary sediment of Fish Clay Højerup (Stevns Klint,Denmark)

We report the occurrence of micrometer-sized silver particles in the red (“impact” or “ejecta”) layer of the Fish Clay. These appear to be embedded into the biogenic/abiogenic calcite matrix. Energy dispersive X-ray analysis indicates that these microparticles are composed of pure silver (>99% of the total weight). Scanning electron microscopy images reveal irregular and predominantly rounded shapes with rugged surfaces. Numerous silver microparticles are spherical, and some exhibit dendritic textures. These microparticles were probably originated during the Chicxulub asteroid impact event, or immediately afterwards, and dispersed globally.     

Hazards and Risks of Recreational Water Use: Vectors of International Studies. Effects of Recreation on Ecosystems and Biota

Water Resources - English-language publications on the assessment of hazards and risks in recreation water use are reviewed. The main themes and results of foreign studies into the effect of...     

Distance estimate of M31 based on the size distribution of Hii regions and dark clouds

The size distribution of dark clouds and of H II regions were used to derive a distance of 440±22 kpc for M31. Some galactic H II regions and dark clouds were combined with the same ingredients in M31 to study the mass spectrum of both phenomena. A gas to dust ratio of 10001 has been derived for M31. Radii of the classical H II regions as derived in this work using distance of 440 kpc agrees with the galactic classical H II region radii.     

Photo—gravitational effects in the two—body problem

The effect of the radiation-pressure in the problem of the two bodies is analysed. It is found that such an effect is the same as that of reducing the stellar mass, m, by the factor p (0 ≤ p ≤ 1). The case p < 0 leads to stellar instability and, consequently, it is not considered here. The problem of the mass determination from spectroscopic observations is reviewed and an iterative method is recommended.     

Synthesis of biochar from sugarcane filter-cake and its impacts on physiological performance of lettuce (<Emphasis Type="Italic">Lettuce sativa</Emphasis>) grown on cadmium contaminated soil

Soil contamination with cadmium has become major concern all over the world because of its adverse impacts on ecosystem health and agricultural land. Soil amendment with biochar may have varied effects on physical and chemical properties of soil. The objective of the study was to explore the impact of sugarcane filter-cake biochar on physiological performance and growth of lettuce in an aged soil. Four different doses (0, 1.5%, 3%, and 5%) of biochar were used in the soil and conditioned for 1 month. After this, lettuce seedlings were grown in the soil. The results showed that the biochar treatment improved the fresh and dry biomass of leaves and roots as well as plant height while diminished the bioavailability of cadmium from the soil. As compared to control, biochar significantly enhanced the chlorophyll content in lettuce leaves. Due to the biochar amendment, the oxidative stress decreased in lettuce shoots over the control. As compared to control, concentration of cadmium in lettuce significantly decreased after the application of biochar. It was concluded that biochar could mitigate the toxicity of cadmium in lettuce by altering the biochemical and physiological processes in cadmium contaminated soil.     

The Magma Feeding System of the Klyuchevskaya Group of Volcanoes (Kamchatka)

Doklady Earth Sciences - Using observations from a large-scale seismic station network, we built a seismic tomography model of velocity anomalies for longitudinal (P-wave) and transverse (S-wave)...