Consulta: subjectFacets:"Biogeochemical cycles"
Registros recuperados: 10
Data/hora: 17/06/2024 13:01:12

Global warming projection of the change in dissolved oxygen concentrations in low oxygen regions of the oceans
Provedor de dados: 72
Autores: Matear,Richard.
Global warming projections using a range of climate models included in the IPCC 4th assessment report (AR4) suggest the oceans will warm, the stratification of the upper ocean will increase and the ventilation of the ocean interior will change. These physical changes will impact dissolved oxygen levels in the ocean. Using a global warming projection from the CSIRO (Australian Commonwealth Scientific and Research Administration) climate model linked to a simple ocean biogeochemical model I investigated how dissolved oxygen levels in the ocean interior change under global warming. The climate simulations project the low oxygen regions like the eastern equatorial Pacific will expand. By the end of the century it is projected that the volume of hypoxic water...
Tipo: Journal article
Palavras-chave: Global warming; Oxygen changes; Anoxia; Biogeochemical cycles; Climate change.
Ano: 2006
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-65382006000300010

Long-term integrated biogeochemical budget driven by circulation in the eastern subpolar North Atlantic
Provedor de dados: 5
Autores: Fontela, Marcos; Mercier, Herle; Pérez, Fiz F.
The eastern subpolar North Atlantic (eSPNA) is a key region in the Atlantic Meridional Overturning Circulation (AMOC), playing an important role in biogeochemical cycles and climate regulation. Quantitative basin-scale biogeochemical budgets are still scarce despite the current need of establishing baselines of knowledge in a changing ocean. The physico-chemical data from the eight repetitions of the OVIDE section (2002-2016) are an unique opportunity to develop a novel evaluation of biogeochemical budgets in the eSPNA by combining robust and well established decadal mean mass transports with carbon variables, oxygen and inorganic nutrients in a full-depth inverse box model. The net balance between the carbon fixation and the respiration throughout the...
Tipo: Text
Palavras-chave: Subpolar North Atlantic; Biogeochemical cycles; Carbon cycle; Nutrient cycles; Oxygenation; Carbon sinks; Oceanic transports.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00480/59206/61898.pdf

Analysis of global surface ocean alkalinity to determine controlling processes
Provedor de dados: 5
Autores: Fry, Claudia H.; Tyrrell, Toby; Hain, Mathis P.; Bates, Nicholas R.; Achterberg, Eric P.
The export of calcium carbonate (CaCO3) from the surface ocean is poorly constrained. A better understanding of the magnitude and spatial distribution of this flux would improve our knowledge of the ocean carbon cycle and marine biogeochemistry. Here, we investigate controls over the spatial distribution of total alkalinity in the surface global ocean and produce a tracer for CaCO3 cycling. We took surface ocean bottle data for total alkalinity from global databases (GLODAP, CARINA, PACIFICA) and subtracted the effects of several processes: evaporation and precipitation, river discharge, and nutrient uptake and remineralization. The remaining variation in alkalinity exhibits a robust and coherent pattern including features of large amplitude and spatial...
Tipo: Text
Palavras-chave: Alkalinity; Calcium carbonate; Biogeochemical cycles; Tracers.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00292/40367/83011.pdf

A latitudinal productivity band in the central North Atlantic over the last 270 kyr: An alkenone perspective
Provedor de dados: 5
Autores: Villanueva, J; Calvo, E; Pelejero, C; Grimalt, Jo; Boelaert, A; Labeyrie, L.
Productivity changes in the central North Atlantic Ocean have been traced by means of the total C-37 alkenone contents along two sediment cores located at 43 degreesN and 37 degreesN. Both alkenone signals revealed the occurrence of discrete productivity events every 23 kyr. Spectral analyses highlight the presence of a dominant 23-kyr periodicity in the alkenone signal, which is highly coherent to the precession index. However, a close comparison revealed small but relevant differences in the timing of several of the productivity events recorded at both locations. These asynchronies suggest that the alkenone maxima do not necessarily reflect a general increase of productivity over the North Atlantic. We propose that the events are related to a latitudinal...
Tipo: Text
Palavras-chave: Biogeochemical cycles; Processes; And modeling Marine organic chemistry Organic and biogenic geochemistry.
Ano: 2001
URL: https://archimer.ifremer.fr/doc/00221/33192/31790.pdf

Dynamique hivernale des nutriments et du carbone dans les exutoires du Marais poitevin et flux terrestres associés en Baie de l’Aiguillon
Provedor de dados: 5
Autores: Le Marchand, Marie.
  Coastal environments represent key systems in biogeochemical cycle couplings between continents, oceans and the atmosphere. Despite its relatively modest surface area (7 % of global ocean), this zone accounts for 14-30 % of all oceanic primary production. The amount of nutrients (N, P, C, Si) carried by terrestrial aquatic systems directly influences the primary production, the food web structure and the overall quality of these coastal environments. The present study deals with autumn-winter carbon and nutrients dynamics over terrestrial waters of the Marais poitevin watershed flowing to the Aiguillon bay (west of France). Five heterogeneous watercourses were sampled twice a month since January 2017 to measure nutrients and carbon concentrations and...
Tipo: Text
Palavras-chave: Zones côtières; Cycles biogéochimiques; Carbone; Nutriments; PCO2; Marais poitevin; Coastal areas; Biogeochemical cycles; Carbon; Nutrients; PCO2; Marais poitevin.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00393/50487/51223.pdf

A Review of the Stable Isotope Bio-geochemistry of the Global Silicon Cycle and Its Associated Trace Elements
Provedor de dados: 5
Autores: Sutton, Jill N.; Andre, Luc; Cardinal, Damien; Conley, Daniel J.; De Souza, Gregory F.; Dean, Jonathan; Dodd, Justin; Ehlert, Claudia; Ellwood, Michael J.; Frings, Patrick J.; Grasse, Patricia; Hendry, Katharine; Leng, Melanie J.; Michalopoulos, Panagiotis; Panizzo, Virginia N.; Swann, George E. A.
Silicon (Si) is the second most abundant element in the Earth's crust and is an important nutrient in the ocean. The global Si cycle plays a critical role in regulating primary productivity and carbon cycling on the continents and in the oceans. Development of the analytical tools used to study the sources, sinks, and fluxes of the global Si cycle (e.g., elemental and stable isotope ratio data for Ge, Si, Zn, etc.) have recently led to major advances in our understanding of the mechanisms and processes that constrain the cycling of Si in the modern environment and in the past. Here, we provide background on the geochemical tools that are available for studying the Si cycle and highlight our current understanding of the marine, freshwater and terrestrial...
Tipo: Text
Palavras-chave: C - N - O - Si isotopes; Biogenic silica; Element/Si ratios; Biogeochemical cycles; Silicon.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00431/54217/55547.pdf

Invasion by the Alien Tree Prunus serotina Alters Ecosystem Functions in a Temperate Deciduous Forest
Provedor de dados: 5
Autores: Aerts, Raf; Ewald, Michael; Nicolas, Manuel; Piat, Jerome; Skowronek, Sandra; Lenoir, Jonathan; Hattab, Tarek; Garzon-lopez, Carol X.; Feilhauer, Hannes; Schmidtlein, Sebastian; Rocchini, Duccio; Decocq, Guillaume; Somers, Ben; Van De Kerchove, Ruben; Denef, Karolien; Honnay, Olivier.
Alien invasive species can affect large areas, often with wide-ranging impacts on ecosystem structure, function, and services. Prunus serotina is a widespread invader of European temperate forests, where it tends to form homogeneous stands and limits recruitment of indigenous trees. We hypotesized that invasion by P. serotina would be reflected in the nutrient contents of the native species' leaves and in the respiration of invaded plots as efficient resource uptake and changes in nutrient cycling by P. serotina probably underly its aggressive invasiveness. We combined data from 48 field plots in the forest of Compiegne, France, and data from an experiment using 96 microcosms derived from those field plots. We used general linear models to separate effects...
Tipo: Text
Palavras-chave: American black cherry; Biological invasion; Biogeochemical cycles; Canopy foliar nutrients; Heterotrophic respiration; Litter; Exotic species; Invasive species.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00398/50981/51739.pdf

Nutrient mineralization rates and ratios in the eastern South Atlantic - art. no. C05030
Provedor de dados: 5
Autores: Brea, Samenta; Alvarez Salgado, X; Alvarez, M; Perez, F; Memery, L; Mercier, Herle; Messias, M.j.
The physical and biogeochemical components of nutrients and inorganic carbon distributions along WOCE line A14 are objectively separated by means of a constrained least-squares regression analysis of the mixing of eastern South Atlantic water masses. Contrary to previous approaches, essentially devoted to the intricate South Atlantic circulation, this work is focused on the effects of circulation on nutrients and carbon biogeochemistry, with special emphasis on the stoichiometry and the rate of mineralization processes. Combination of nutrient and apparent CFC-age anomalies, derived from the mixing analysis, indicate faster mineralization rates in the equatorial (12 x 10(-2) mumol P kg(-1) yr(-1)) and subequatorial (5.3 x 10(-2) mumol P kg(-1) yr(-1)) than...
Tipo: Text
Palavras-chave: South Atlantic; Biogeochemical cycles; Water masses.
Ano: 2004
URL: https://archimer.ifremer.fr/doc/2004/publication-836.pdf

IMBER - Research for marine sustainability: Synthesis and the way forward
Provedor de dados: 5
Autores: Hofmann, Eileen; Bundy, Alida; Drinkwater, Ken; Piola, Alberto R.; Avril, Bernard; Robinson, Carol; Murphy, Eugene; Maddison, Lisa; Svendsen, Einar; Hall, Julie; Xu, Yi.
The Integrated Marine Biogeochemistry and Ecosystem Research (IMBER) project aims at developing a comprehensive understanding of and accurate predictive capacity of ocean responses to accelerating global change and the consequent effects on the Earth system and human society. Understanding the changing ecology and biogeochemistry of marine ecosystems and their sensitivity and resilience to multiple drivers, pressures and stressors is critical to developing responses that will help reduce the vulnerability of marine-dependent human communities. This overview of the IMBER project provides a synthesis of project achievements and highlights the value of collaborative, interdisciplinary, integrated research approaches as developed and implemented through IMBER...
Tipo: Text
Palavras-chave: IMBER; Global environmental change; Marine ecosystems; Biogeochemical cycles; Human systems; Marine sustainability.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00383/49441/49932.pdf

Modelling of oxygen and nitrogen cycling as a function of macrophyte community in the Thau lagoon
Provedor de dados: 5
Autores: Plus, Martin; Chapelle, Annie; Lazure, Pascal; Auby, Isabelle; Levavasseur, G; Verlaque, M; Belsher, Thomas; Deslous-paoli, Jean-marc; Zaldivar, J; Murray, C.
A three-dimensional model coupling physical and biological processes for the whole Than lagoon (Mediterranean coast of France) was developed in order to assess the relationships between macrophytes and the oxygen and nitrogen cycles. Ten species have been inserted as forcing variables in the model. Plankton dynamics, shellfish cultivation impact and mineralization of organic matter are also considered, as well as nutrient and oxygen exchanges between the sediment and the water column.   Simulations with and without the macrophytes have shown that the system can be characterized as having a highly structured pattern involving lagoon nitrogen and oxygen cycles. This pattern is created by the combined influence of macrophytes, watershed and oyster farming....
Tipo: Text
Palavras-chave: Thau lagoon; Biogeochemical cycles; Ecological modelling; Macrophytes.
Ano: 2003
URL: https://archimer.ifremer.fr/doc/2003/publication-459.pdf