نتایج جستجو برای: detrital deposit

تعداد نتایج: 19486  

2002
Lee A. Dyer Deborah Letourneau

Lee A. Dyer* and Deborah Letourneau Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, LA 70118, USA Department of Environmental Studies, University of California, Santa Cruz, CA 95064, USA *Correspondence: E-mail: [email protected] Abstract Apex predators and plant resources are both critical for maintaining diversity in biotic communities, but the indirect ( cascad...

2010
M. Bernet

The European Alps are a mountain belt that is characterized by a series of discrete orogenic events, which have long been recognized. Despite the inherent episodic nature of orogenic evolution, the Alps have been continuously exhumed, mainly by erosion, but also by normal faulting. Since continental collision started in the late Eocene/Early Oligocene evidence for ongoing erosional exhumation h...

Journal: :Global change biology 2016
Adrian B Burd Serita Frey Anna Cabre Takamitsu Ito Naomi M Levine Christian Lønborg Matthew Long Marguerite Mauritz R Quinn Thomas Brandon M Stephens Tom Vanwalleghem Ning Zeng

Organic matter (OM) plays a major role in both terrestrial and oceanic biogeochemical cycles. The amount of carbon stored in these systems is far greater than that of carbon dioxide (CO2 ) in the atmosphere, and annual fluxes of CO2 from these pools to the atmosphere exceed those from fossil fuel combustion. Understanding the processes that determine the fate of detrital material is important f...

Journal: :Journal of environmental quality 2017
T Adam Coates Alex T Chow Donald L Hagan G Geoff Wang William C Bridges James H Dozier

The O horizon, or detrital layer, of forest soils is linked to long-term forest productivity and health. Fuel reduction techniques, such as prescribed fire, can alter the thickness and composition of this essential ecosystem component. Developing an understanding of the changes in the chemical composition of forest detritus due to prescribed fire is essential for forest managers and stakeholder...

2006
GEORGE GEHRELS VICTOR VALENCIA ALEX PULLEN

Detrital zircon geochronology is rapidly evolving into a very powerful tool for determining the provenance and maximum depositional age of clastic strata. This rapid evolution is being driven by the increased availability of ion probes and laser ablation ICP mass spectrometers, which are able to generate age determinations rapidly, at moderate to low cost, and of sufficient accuracy for most ap...

2010
George Georgiadis Christopher S. Tang

We study two reservation deposit policies for a service rm to increase its revenue through higher capacity utilization. First, under the no deposit policy, the rm requires no reservation deposit and imposes no no show penalty. Anticipating potential no shows, a rm may overbook; hence, there is no guarantee that the reserved service will be provided under the no deposit policy. On the contrary, ...

2014
Louie H Yang Claudio Gratton

Insects and other small invertebrates are ubiquitous components of all terrestrial and freshwater food webs, but their cumulative biomass is small relative to plants and microbes. As a result, it is often assumed that these animals make relatively minor contributions to ecosystem processes. Despite their small sizes and cumulative biomass, we suggest that these animals may commonly have importa...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2015
Sigrún Huld Jónasdóttir André W Visser Katherine Richardson Michael R Heath

Estimates of carbon flux to the deep oceans are essential for our understanding of global carbon budgets. Sinking of detrital material ("biological pump") is usually thought to be the main biological component of this flux. Here, we identify an additional biological mechanism, the seasonal "lipid pump," which is highly efficient at sequestering carbon into the deep ocean. It involves the vertic...

2009
Robert E. Kopp Dirk Schumann Timothy D. Raub David S. Powars Linda V. Godfrey Nicholas L. Swanson-Hysell Adam C. Maloof Hojatollah Vali

On the mid-Atlantic Coastal Plain of the United States, Paleocene sands and silts are replaced during the Paleocene-Eocene Thermal Maximum (PETM) by the kaolinite-rich Marlboro Clay. The clay preserves abundant magnetite produced by magnetotactic bacteria and novel, presumptively eukaryotic, iron-biomineralizing microorganisms. Using ferromagnetic resonance spectroscopy and electron microscopy,...

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