Rheological analysis of mud from Port of Hamburg,Germany

Journal of Soils and Sediments - An innovative way to define navigable fluid mud layers is to make use of their rheological properties, in particular their yield stress. In order to help the...     

Nina Georgiyevna Minashina January 14, 1927 to September 6, 2010

Obituaries

Nina Georgiyevna Minashina January 14, 1927 to September 6, 2010     

Multiple Wavelength Ultraviolet Determinations of Nitrate Concentration, Method Comparisons from the Preakness Brook Monitoring Project, October 2005 to October 2006

The direct spectrophotometric analysis of aqueous nitrates is a simple analytical procedure but prone to interferences. A twelve-month study of the Preakness Brook in Wayne Township, New Jersey demonstrated that two wavelength, three wavelength, and second derivative calculation methods provide very different results from the same ultraviolet absorption spectrum. On average, the two wavelength and second derivative methods yielded the same concentration at each sample point over the entire study period. These methods provided concentration results closest to those obtained by ion chromatography and significantly lower than the three wavelength computation method. The degree of variation between the different computation methods was not consistent as it rose with increasing absorbances at wavelengths associated with interfering compounds. This variation was especially pronounced between May and August.     

Boris Petrovich Gradusov (February 24, 1932 to September 2, 2010)

Obituaries

Boris Petrovich Gradusov (February 24, 1932 to September 2, 2010)     

冬小麦产量与底墒关系分析

该在分析大量试验资料后指出：在黄土高原南部地区，冬小麦产量与播前底墒相关性强，其相关系数在不同施肥水平下，分别为：中肥处理０．６７７；高肥处理０．７４２；单施氮处理高达０．９６０。因而得出不同施肥处理下的底墒与冬小麦产量关系图，可用于冬小麦产量趋势预测及建立数学模型参考。     

Temporal and Elevation-Related Variability in Precipitation Chemistry from 1993 to 2002, Eastern Erzgebirge, Germany

The Erzgebirge, part of the so-called former “Black Triangle”, used to represent the strongest regional air pollution of Central Europe. To test the hypothesis of deposition enhancement with height, an altitudinal gradient along a N-S transect from the Elbe river lowlands to the Erzgebirge summit was chosen to investigate chemical composition, elevation-related variability, temporal changes, and seasonal patterns of ion concentrations from 1993 to 2002. The following questions were to be answered: (1) Which role does orography play on the composition of precipitation?, (2) Does fog occurrence overrule the orographic influence?, (3) Are there changes in the past 10 years, and if so, why?, (4) Do relevant seasonal changes occur and why? Air streams from westerly and to a lesser degree south-easterly directions prevail. The average precipitation was ion-poor (23 μS cm^?1 and acidic (pH 4.5). Sulphate still was the dominant anion (52.3–59.9 μeq L^?1, while NH⁺ ₄ determined the cations (41.9–62.2 μeq L^?1. Ion concentrations decreased with altitude to about 735 m a.s.l. and subsequently increased. The seeder-feeder effect largely explains the chemical composition of precipitation; enhanced in winter through snow crystals. Sub-cloud scavenging does not explain the observed patterns. Fog occurrence enhanced the observed effects at higher altitudes. Deposition amounts doubled from the lowlands to the Erzgebirge summit. From 1993 to 2002, acidity decreased by about 50%, mainly due to reduced SO₂ -emissions.     

New Zealand's first marine reserve,Cape Rodney to Okakari point,Leigh

New Zealand's first marine reserve, Cape Rodney to Okakari Point, with an area of 500 ha, occupies a portion of the north-eastern coastline centred on a small island. The physical and biological characteristics of the reserve are outlined. It was opened in 1977, twelve years after it was first proposed. The problems encountered and lessons learned from trying to establish a nation's first marine reserve are discussed.     

为21世纪土壤科学的创新发展作出新的贡献——参加第17届国际土壤学大会综述

今年8月14～21日，在泰国曼谷召开了第17届国际土壤学大会，这是在21世纪首次举行的全球性的土壤科学学术盛会。在14日的开幕式上，泰国皇家王室M C Sirindhorn公主亲莅会场致开幕词，并为大会展览厅揭幕。曼谷市市长、泰国土地发展部部长、本届国际土壤学会主席及秘书长等人在     

Phosphorus Entrainment Due to Resuspension in a Lowland River, Spree, NE Germany – A Laboratory Microcosm Study

Resuspension of benthic phosphorus (P) often constitutes a high percentage of the annual P flux in lowland rivers. To study P entrainment at controlled shear velocity (u*) sediment from lowland River Spree of slower flowing (0.1–0.3 m s^?1) stretch Kossenblatt (KOB) and of faster flowing (0.5–0.7 m s^?1) stretch Freienbrink (FRB) was incubated in a microcosm at incrementally enhanced u* (0.34–1.9 cm s^?1). Particle and P entrainment rates as well as the number of particle-associated bacteria of fine-grained mud-like KOB sediment were much higher (16.7 g m^?2 h^?1, 104.9 mg P m^?2 h^?1, 15.47 10⁶ cells ml^?1) than those (4.3 g m^?2 h^?1, 2.1 mg P m^?2 h^?1, 3.06 10⁶ cells ml^?1) of coarser sandy FRB sediment. The microcosm used so far in marine research is suited to compare riverine resuspension suggesting the lower u* the more particles are deposited and the more P can be retained (KOB ? FRB). Conversely, correspondingly more and easier particulate P and bacteria can again be remobilised (KOB ? FRB) if u* increases. The general relationship found for u* and the entrainment of particulate P and bacteria as well as their decelerated and selective deposition where bacteria may stay longer in the water implies a temporarily enhanced P bioavailability, turnover and subsequent P transformations.