نتایج جستجو برای: ecosystem cycles

تعداد نتایج: 171643  

2012
David W. Schindler

The management of eutrophication has been impeded by reliance on short-term experimental additions of nutrients to bottles and mesocosms. These measures of proximate nutrient limitation fail to account for the gradual changes in biogeochemical nutrient cycles and nutrient fluxes from sediments, and succession of communities that are important components of whole-ecosystem responses. Erroneous a...

2017
Carlos E Oyarzún Pedro Hervé-Fernandez

Nitrogen (N) cycling in terrestrial ecosystems is a global environmental concern. The N cycle is a complex interplay where biotic and abiotic processes interact to transform and transfer N in an ecosystem. In general, one can simplify by classifying terrestrial N cycles all over the world in two groups: ‘tight’ N cycles and ‘open’ N cycles. The ‘tight’ N cycle is characterized by its high effic...

2016
Rudy Boonstra Harry P. Andreassen Stan Boutin Jan Hušek Rolf A. Ims Charles J. Krebs Christina Skarpe Petter Wabakken

The boreal forest is one of the largest terrestrial biomes on Earth. Conifers normally dominate the tree layer across the biome, but other aspects of ecosystem structure and dynamics vary geographically. The cause of the conspicuous differences in the understory vegetation and the herbivore-predator cycles between northwestern Europe and western North America presents an enigma. Ericaceous dwar...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2014
Markus Reichstein Michael Bahn Miguel D Mahecha Jens Kattge Dennis D Baldocchi

Classical biogeographical observations suggest that ecosystems are strongly shaped by climatic constraints in terms of their structure and function. On the other hand, vegetation function feeds back on the climate system via biosphere-atmosphere exchange of matter and energy. Ecosystem-level observations of this exchange reveal very large functional biogeographical variation of climate-relevant...

2016
Thomas Mock Stuart J. Daines Richard Geider Sinead Collins Metodi Metodiev Andrew J. Millar Vincent Moulton Timothy M. Lenton

The advent of genomic-, transcriptomic- and proteomic-based approaches has revolutionized our ability to describe marine microbial communities, including biogeography, metabolic potential and diversity, mechanisms of adaptation, and phylogeny and evolutionary history. New interdisciplinary approaches are needed to move from this descriptive level to improved quantitative, process-level understa...

2016
Bo Li Chunlan Du Xingzhong Yuan J. H. Martin Willison Hongyan Xiao Manuel Reigosa

The littoral zone ecosystem of the Three Gorges Reservoir (TGR) has become significantly degraded by annual cycles of prolonged winter flooding and summer drought. For purposes of flood control and sediment management, the water level in the reservoir is lowered by 30 m during the summer monsoon season and raised again to 175 m above sea level each year at the end of the monsoon period. To expl...

2014
Heidi J. Renninger Kenneth L. Clark Karina V.R. Schäfer Nicholas Carlo Karina V. R. Schäfer

Although snags and coarse woody debris are a small component of ecosystem respiration, disturbances can significantly increase the mass and respiration from these carbon (C) pools. The objectives of this study were to (1) measure respiration rates of snags and coarse woody debris throughout the year in a forest previously defoliated by gypsy moths, (2) develop models for dead stem respiration r...

2017
Alexandra Bähring Andreas Fichtner Uta Friedrich Goddert von Oheimb Werner Härdtle

The effects of atmospheric nitrogen (N) deposition on ecosystem functioning largely depend on the retention of N in different ecosystem compartments, but accumulation and partitioning processes have rarely been quantified in long-term field experiments. In the present study we analysed for the first time decadal-scale flows and allocation patterns of N in a heathland ecosystem that has been sub...

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