نتایج جستجو برای: sediment threshold

تعداد نتایج: 158501  

2014
Kaipo Perez Kuʻulei S. Rodgers Paul L. Jokiel Claire V. Lager Daniel J. Lager

Survival and settlement of Pocillopora damicornis larvae on hard surfaces covered with fine (<63 µm) terrigenous red clay was measured in laboratory Petri dishes. The dishes were prepared with sediment films of various thicknesses covering the bottoms. Coral larvae were incubated in the dishes for two weeks and the percent that settled on the bottom was determined. There was a statistically sig...

2016
Bao Son Trinh Brian Reid Kevin Hiscock

BACKGROUND Sorption and biodegradation are the primary processes of organic pollution remediation in aquatic and soil/sediment environments. While researchers have substantially reported their findings regarding these processes, little attention has been given to description of experimental apparatus. This technical paper aims to present the development and detailed design of a fixed-bed column...

2013
Beth N. Orcutt Douglas E. LaRowe Jennifer F. Biddle Frederick S. Colwell Brian T. Glazer Brandi Kiel Reese John B. Kirkpatrick Laura L. Lapham Heath J. Mills Jason B. Sylvan Scott D. Wankel C. Geoff Wheat

The vast marine deep biosphere consists of microbial habitats within sediment, pore waters, upper basaltic crust and the fluids that circulate throughout it. A wide range of temperature, pressure, pH, and electron donor and acceptor conditions exists-all of which can combine to affect carbon and nutrient cycling and result in gradients on spatial scales ranging from millimeters to kilometers. D...

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2016
Dominic A Hodgson Michael J Bentley James A Smith Julian Klepacki Keith Makinson Andrew M Smith Kevin Saw Reed Scherer Ross Powell Slawek Tulaczyk Mike Rose David Pearce Matt Mowlem Peter Keen Martin J Siegert

Accumulations of sediment beneath the Antarctic Ice Sheet contain a range of physical and chemical proxies with the potential to document changes in ice sheet history and to identify and characterize life in subglacial settings. Retrieving subglacial sediments and sediment cores presents several unique challenges to existing technologies. This paper briefly reviews the history of sediment sampl...

2006
J. Belnap S. L. Phillips J. E. Herrick J. R. Johansen

Recently disturbed and ‘control’ (i.e. less recently disturbed) soils in the Mojave Desert were compared for their vulnerability to wind erosion, using a wind tunnel, before and after being experimentally trampled. Before trampling, control sites had greater cyanobacterial biomass, soil surface stability, threshold friction velocities (TFV; i.e. the wind speed required to move soil particles), ...

1998
KENNETH L. FROESE DAVID A. VERBRUGGE GERALD T. ANKLEY GERALD J. NIEMI CHRISTEN P. LARSEN JOHN P. GIESY

Sediments in the Saginaw Bay region of the Great Lakes contain concentrations of polychlorinated biphenyls (PCBs) that may adversely affect biotic species in various trophic levels. In this study we collected and analyzed sediments, benthic invertebrates, tree swallow eggs, and nestlings to evaluate linkages between PCBs in sediments and at various trophic levels in the Saginaw River, Michigan,...

Journal: :مرتع و آبخیزداری 0
سیدمسعود سلیمان پور دانشجوی دکتری علوم و مهندسی آبخیزداری، دانشگاه آزاد اسلامی واحد علوم و تحقیقات تهران، ایران مجید صوفی استادیار پژوهشی مرکز تحقیقات کشاورزی و منابع طبیعی استان فارس، ایران حسن احمدی استاد دانشکده منابع طبیعی، دانشگاه تهران، ایران

gully erosion has an important role in fars province due to sediment production and enormous damages to land, roads and infrastructures. in this research, 15 gullies were selected to measure their morphometric characteristics. the length, depth, top and bottom width and volume of gully erosion were then measured. influential factors on the sediment production and gully development were analyzed...

2007
A. Gnauck

Natural and man induced nutrient loads affect the functioning of freshwater ecosystems and restrict various water uses. In particular, internal pollution by nutrient remobilisation from sediment plays an important role in shallow water bodies. A sustainable management of such freshwater ecosystems can be achieved by using simulation models. To forecast the eutrophication process of a shallow ri...

Journal: :Journal of environmental sciences 2014
Fengyu Zan Shouliang Huo Jingtian Zhang Li Zhang Beidou Xi Lieyu Zhang

Arsenic (As) fractions in the sediments of seven lakes from East Plain Ecoregion and six lakes from Yungui Plateau Ecoregion, China, were investigated. Results indicated that the total As concentrations in sediment samples of lakes of the East Plain Lake Ecoregion are higher than those of Yungui Plateau Lake Ecoregion. Residual As is the main fraction in sediment samples of lakes from both ecor...

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