Topic
Ecosystem
About: Ecosystem is a research topic. Over the lifetime, 25460 publications have been published within this topic receiving 1291375 citations. The topic is also known as: ecological system & Ecosystem.
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TL;DR: It is argued that the priming effect acts substantially in the carbon and nutrient cycles in all ecosystems, which could provide new insights on the responses of ecosystems to anthropogenic perturbations and their feedbacks to climatic changes.
Abstract: Understanding how ecosystems store or release carbon is one of ecology's greatest challenges in the 21st century. Organic matter covers a large range of chemical structures and qualities, and it is classically represented by pools of different recalcitrance to degradation. The interaction effects of these pools on carbon cycling are still poorly understood and are most often ignored in global-change models. Soil scientists have shown that inputs of labile organic matter frequently tend to increase, and often double, the mineralization of the more recalcitrant organic matter. The recent revival of interest for this phenomenon, named the priming effect, did not cross the frontiers of the disciplines. In particular, the priming effect phenomenon has been almost totally ignored by the scientific communities studying marine and continental aquatic ecosystems. Here we gather several arguments, experimental results, and field observations that strongly support the hypothesis that the priming effect is a general phenomenon that occurs in various terrestrial, freshwater, and marine ecosystems. For example, the increase in recalcitrant organic matter mineralization rate in the presence of labile organic matter ranged from 10% to 500% in six studies on organic matter degradation in aquatid ecosystems. Consequently, the recalcitrant organic matter mineralization rate may largely depend on labile organic matter availability, influencing the CO2 emissions of both aquatic and terrestrial ecosystems. We suggest that (1) recalcitrant organic matter may largely contribute to the CO2 emissions of aquatic ecosystems through the priming effect, and (2) priming effect intensity may be modified by global changes, interacting with eutrophication processes and atmospheric CO2 increases. Finally, we argue that the priming effect acts substantially in the carbon and nutrient cycles in all ecosystems. We outline exciting avenues for research, which could provide new insights on the responses of ecosystems to anthropogenic perturbations and their feedbacks to climatic changes.
419 citations
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International Institute of Minnesota1, University of Connecticut2, University of Alabama3, Wageningen University and Research Centre4, University of Regina5, University of Puerto Rico6, National Autonomous University of Mexico7, Brown University8, University of São Paulo9, Leipzig University10, Smithsonian Tropical Research Institute11, Federal University of Pernambuco12, Tulane University13, University of Stirling14, Clemson University15, University of Alberta16, National Institute of Amazonian Research17, Colorado Mesa University18, State University of New York at Purchase19, World Agroforestry Centre20, Columbia University21, Aarhus University22, University of Minnesota23, University of California, Santa Barbara24, Pedagogical and Technological University of Colombia25, University of Maryland, College Park26, Yale-NUS College27, National University of Singapore28, Puerto Rico Department of Agriculture29, University of Amsterdam30, Museu Paraense Emílio Goeldi31, Louisiana State University32
TL;DR: This study estimates the age and spatial extent of lowland second-growth forests in the Latin American tropics and model their potential aboveground carbon accumulation over four decades to guide national-level forest-based carbon mitigation plans.
Abstract: Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We estimate the age and spatial extent of lowland second-growth forests in the Latin American tropics and model their potential aboveground carbon accumulation over four decades. Our model shows that, in 2008, second-growth forests (1 to 60 years old) covered 2.4 million km2 of land (28.1% of the total study area). Over 40 years, these lands can potentially accumulate a total aboveground carbon stock of 8.48 Pg C (petagrams of carbon) in aboveground biomass via low-cost natural regeneration or assisted regeneration, corresponding to a total CO2 sequestration of 31.09 Pg CO2. This total is equivalent to carbon emissions from fossil fuel use and industrial processes in all of Latin America and the Caribbean from 1993 to 2014. Ten countries account for 95% of this carbon storage potential, led by Brazil, Colombia, Mexico, and Venezuela. We model future land-use scenarios to guide national carbon mitigation policies. Permitting natural regeneration on 40% of lowland pastures potentially stores an additional 2.0 Pg C over 40 years. Our study provides information and maps to guide national-level forest-based carbon mitigation plans on the basis of estimated rates of natural regeneration and pasture abandonment. Coupled with avoided deforestation and sustainable forest management, natural regeneration of second-growth forests provides a low-cost mechanism that yields a high carbon sequestration potential with multiple benefits for biodiversity and ecosystem services.
419 citations
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01 Jan 1988
TL;DR: Pelagic Nitrogen Cycling: Primary Productivity and Pelagic nitrogen cycling Pelagic primary production in nearshore waters Microfauna in Pelagic Food Chains Benthic Nitrogen cycling: BenthIC primary production and Oxygen Profiles Benthicity Nitrogen Fixation Amino Acids and Amines in Marine Particulate Material and Sediments Distribution and Metabolism of Quaternary Amines and Bacterial Production Nitrogen in Estuarine and Coastal Marine Sediments Nitrate Reduction and Denitrification in Marine Sediements.
Abstract: Pelagic Nitrogen Cycling: Primary Productivity and Pelagic Nitrogen Cycling Pelagic Primary Production in Nearshore Waters Microfauna in Pelagic Food Chains Benthic Nitrogen Cycling: Benthic Primary Production and Oxygen Profiles Benthic Nitrogen Fixation Amino Acids and Amines in Marine Particulate Material and Sediments Distribution and Metabolism of Quaternary Amines in Marine Sediments Benthic Mineralization and Bacterial Production Nitrogen in Benthic Food Chains Nitrification in Estuarine and Coastal Marine Sediments Nitrate Reduction and Denitrification in Marine Sediments Benthic Fauna and Biogeochemical Processes in Marine Sediements: The Role of Burrow Structures Benthic Fauna and Biogeochemical Processes in Marine Sediments: Microbial Activities and Fluxes Models of Nitrogen Cycling: Modelling Benthic Nitrogen Cycling in Temperate Coastal Ecosystems Nitrogen Models at the Community Level: Plant-Animal-Microbe Interactions Nitrogen Biogeochemistry and Modelling of Carmarthen Bay.
417 citations
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TL;DR: A leaky nitrostat model is proposed that is capable of resolving the paradox at scales of both ecosystems and individual N-fixing organisms.
Abstract: Observations of the tropical nitrogen (N) cycle over the past half century indicate that intact tropical forests tend to accumulate and recycle large quantities of N relative to temperate forests, as evidenced by plant and soil N to phosphorus (P) ratios, by P limitation of plant growth in some tropical forests, by an abundance of N-fixing plants, and by sustained export of bioavailable N at the ecosystem scale. However, this apparent up-regulation of the ecosystem N cycle introduces a biogeochemical paradox when considered from the perspective of physiology and evolution of individual plants: The putative source for tropical N richness—symbiotic N fixation—should, in theory, be physiologically down-regulated as internal pools of bioavailable N build. We review the evidence for tropical N richness and evaluate several hypotheses that may explain its emergence and maintenance. We propose a leaky nitrostat model that is capable of resolving the paradox at scales of both ecosystems and individual N-fixing organisms.
416 citations
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TL;DR: A systematic and holistic approach to investigate how soil and plant community characteristics change with altered precipitation regimes and the consequent effects on ecosystem processes and functioning within these experiments will greatly increase their value to the climate change and ecosystem research communities.
Abstract: Climatic changes, including altered precipitation regimes, will affect key ecosystem processes, such as plant productivity and biodiversity for many terrestrial ecosystems. Past and ongoing precipitation experiments have been conducted to quantify these potential changes. An analysis of these experiments indicates that they have provided important information on how water regulates ecosystem processes. However, they do not adequately represent global biomes nor forecasted precipitation scenarios and their potential contribution to advance our understanding of ecosystem responses to precipitation changes is therefore limited, as is their potential value for the development and testing of ecosystem models. This highlights the need for new precipitation experiments in biomes and ambient climatic conditions hitherto poorly studied applying relevant complex scenarios including changes in precipitation frequency and amplitude, seasonality, extremity and interactions with other global change drivers. A systematic and holistic approach to investigate how soil and plant community characteristics change with altered precipitation regimes and the consequent effects on ecosystem processes and functioning within these experiments will greatly increase their value to the climate change and ecosystem research communities. Experiments should specifically test how changes in precipitation leading to exceedance of biological thresholds affect ecosystem resilience and acclimation.
416 citations