Дисертації з теми "Coastal carbon cycling"
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Blount, Keyyana. "Land Use Effects on Carbon Cycling in Oregon Coastal Wetlands." Thesis, University of Oregon, 2018. http://hdl.handle.net/1794/23152.
Повний текст джерелаParkes, Duncan James. "Storage and cycling of organic carbon and nutrients in Holocene coastal sediments." Thesis, University of East Anglia, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396713.
Повний текст джерелаGacengo, Catherine N. Wood C. W. Shaw Joey N. "Agroecosystem management effects on carbon and nitrogen cycling across a coastal plain catena." Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SUMMER/Agronomy_and_Soils/Dissertation/Gacengo_Catherine_2.pdf.
Повний текст джерелаHenley, Sian Frances. "Climate-induced changes in carbon and nitrogen cycling in the rapidly warming Antarctic coastal ocean." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/7626.
Повний текст джерелаSjoeberg, Tristan Nenne. "The distribution and cycling of dissolved carbon monoxide in estuarine, coastal and shelf break environments." Thesis, University of East Anglia, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302077.
Повний текст джерелаLacroix, Fabrice. "Riverine and coastal ocean contributions to the global and regional oceanic cycling of carbon and nutrients." Doctoral thesis, Universite Libre de Bruxelles, 2019. https://dipot.ulb.ac.be/dspace/bitstream/2013/289460/3/main.pdf.
Повний текст джерелаRiver deliver vast amounts of terrestrially derived compounds to the ocean. These fluxes are of particular importance for the coastal ocean, which is recognized as a region of disproportionate contribution to global oceanic biological fluxes. Until now, the riverine carbon, nutrient and alkalinity inputs have been poorly represented or omitted in global ocean biogeochemistry models. In particular, there has yet to be a model that considers the pre-industrial riverine loads of biogeochemical compounds to the ocean, and terrestrial inputs of organic matter are greatly simplified in their composition and reactivities in the ocean. Furthermore, the coastal ocean and its contribution to the globalcarbon cycle have remained enigmatic, with little attention being paid to this area of high biological productivity in global model analysis of carbon fluxes. Lastly, 20 th century perturbations in riverine fluxes as well as of the physical and biogeochemical states of the coastal ocean have remained unexplored in a 3-dimensional model. Thus, the main goals of this thesis are to integrate an improved representation of riverine supplies in a global ocean model, as well as to improve the representation of the coastal ocean in the model, in order to solve open questions with respect its global contributions to carbon cycling.In this thesis, I first aimed to close gaps of knowledge in the long-term implications of pre-industrial riverine loads for the oceanic cycling of carbon in a novel framework. I estimated pre-industrial biogeochemical riverine loads and their spatial distributions derived from Earth System Model variables while using a hierarchy of state-of-the-art weathering and organic matter land-ocean export models. I incorporated these loads into the global ocean biogeochemical model HAMOCC and investigated the induced changes in oceanic biological production and in the air-sea carbon flux, both at the global scale and in a regional shelf analysis. Finally, I summarized the results by assessing the net land sink of atmospheric carbon prescribed by the terrestrial models, and comparing it to the long-term carbon outgassing determined in the ocean model. The study reveals a pre-industrial oceanic outgassing flux of 231 Tg C yr -1 ,which is found to a large degree in proximity to the river mouths. The model also indicates an interhemispheric transfer of carbon from dominant northern hemisphere riverine inputs to outgassing in the southern hemisphere. Furthermore, I observe substantial riverine-induced increases in biological productivity in the tropical West Atlantic (+166 %), the Bay of Bengal (+377 %) and in the East China Sea (+71 %), in comparison to a model simulation which does not consider the riverine inputs.In addition to considering supplies provided by riverine fluxes, the biogeochemical representation of the coastal ocean is improved in HAMOCC, by firstly increasing organic matter remineralization rates in the coastal sediment and by secondly explicitly representing the breakdown process of terrestrial dissolved organic matter (tDOM) in the ocean. In an analysis of the coastal fluxes, the model shows a much shorter residence time of coastal waters (14-16 months) than previously assumed, which leads to an efficient cross-shelf transport of organic matter and a net autotrophic state for both the pre-industrial timeframe and the present day. The coastal ocean is also revealed as a CO2 sink for the pre-industrial time period (0.06-0.08 Pg C yr -1 ) in contrary to to the suggested source in published literature. The sink is however not only caused by the autotrophic state of the coastal ocean, but it is likely also strongly influenced by the effects of biological alkalinity production, as well as both physical and biogeochemical characteristics of open ocean inflows.In the final chapter, 20 th century oceanic perturbations due to changes in atmospheric CO 2 concentrations and in the physical climate, and to increases in riverine nutrient supplies were investigated by using sequential model simulations. The model results show that the decrease in the net primary production (NPP) in the tropical and subtropical oceans due to temperature-induced stratification may be completely compensated by increases in the Southern Ocean and in Eastern Boundary Upwelling Systems (EBUS). The model also reveals that including increases in riverine supplies causes a global ocean NPP increase of +4 %, with the coastal ocean being a particularlystrongly affected region (+15 %).This thesis shows a strong necessity to represent spatio-temporal changes in riverine supplies and of the coastal ocean state in spatially explicit global models in order to assess changes of the global cycling of carbon in the ocean in the past and potentially in the future.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Hardison, Amber Kay. "Interactions between macroalgae and the sediment microbial community : nutrient cycling within shallow coastal bays /." W&M ScholarWorks, 2009. http://web.vims.edu/library/Theses/Hardison09.pdf.
Повний текст джерелаNilsen, Elena Brennan. "Studies of carbon cycling, nutrient dynamics and climate change in pelagic and coastal ecosystems using sediment geochemical techniques /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2004. http://uclibs.org/PID/11984.
Повний текст джерелаWilson, Benjamin J. "Drivers and Mechanisms of Peat Collapse in Coastal Wetlands." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3718.
Повний текст джерелаDyksma, Stefan [Verfasser], Marc [Akademischer Betreuer] Mußmann, Rudolf [Gutachter] Amann, and Ulrich [Gutachter] Fischer. "Identification and activity of bacteria consuming key intermediates of carbon and sulfur cycling in coastal sands / Stefan Dyksma ; Gutachter: Rudolf Amann, Ulrich Fischer ; Betreuer: Marc Mußmann." Bremen : Staats- und Universitätsbibliothek Bremen, 2016. http://d-nb.info/1113718781/34.
Повний текст джерелаFrank-Fahle, Béatrice A. "Methane-cycling microbial communities in permafrost affected soils on Herschel Island and the Yukon Coast, Western Canadian Arctic." Phd thesis, Universität Potsdam, 2013. http://opus.kobv.de/ubp/volltexte/2013/6534/.
Повний текст джерелаPermafrost beeinflusste Ökosysteme gehören zu den Regionen, in denen als Folge der globalen Erwärmung eine Veränderung des mikrobiell-kontrollierten Abbaus von organischem Material zu erwarten ist. Besonders in den Ökosystemen der feuchten Tundralandschaften kommt es zu einer verstärkten Methanpoduktion unter wassergesättigten und anoxischen Bedingungen, die durch immer tiefere saisonale Auftauschichten begünstigt werden. Die vorliegende Doktorarbeit kontenzentrierte sich auf die Untersuchung der Abundanz und Verteilung der am Methankreislauf beteiligten mikrobiellen Gemeinschaften in vier unterschiedlichen Polygonen auf der Insel Herschel und an der Yukon Küste in Kanada. Trotz des relevanten Beitrags der kanadischen West-Arktis am globalen Methanhaushalt, sind die dortigen mikrobiellen Gemeinschaften im Permafrost bisher nur unzureichend untersucht worden. Die zentrale Zielstellung der vorliegenden Arbeit besteht darin, die derzeitige Lücke im Verständnis der Kohlenstoffdynamik in der Arktis im Zuge von Klimaveränderungen und deren Bedeutung für den Methankreislauf in Permafrost-Ökosystemen zu schließen. Dies erfolgt durch Untersuchungen der am Abbau der organischen Substanz im Permafrost beteiligten methonogenen und methanothrophen mikrobiellen Gemeinschaften und ihrer möglichen Reaktionen auf steigende Umgebungstemperaturen. Um dieses Ziel zu erreichen, wurde ein Multiproxy-Ansatz gewählt, der die Analyse der Gemeinschaften mittels genetischen Fingerprintmethoden, Klonierung, quantitativer PCR und moderner Hochdurchsatzsequenzierung („Next Generation Sequencing“) beinhaltet, um die in der Auftauschicht der vier untersuchten Polygone vorhandenen Bakterien- und Archaeen-Gemeinschaften zu charakterisieren sowie die Diversität und Verteilung der am Methankreislauf beteiligten Mikroorganismen in unterschiedlicher Tiefe eingehend zu analysieren. Diese Studien wurden mit physikalisch-chemischen Habitatuntersuchungen kombiniert, da diese die mikrobiellen Lebensgemeinschaften maßgeblich beeinflussen. Zusätzlich wurde ein Laborexperiment zur Simulation der Klimaerwärmung an intakten Bodenmonolithen von der Insel Herschel durchgeführt, um die Veränderungen der am Methankreislauf beteiligten Gemeinschaften aufgrund steigender Bodentemperaturen zu untersuchen, sowie sicherere Voraussagen bezüglich der Methanfreisetzung in polygonalen Permafrostgebieten im Zusammenhang mit dem Klimawandel treffen zu können.
Johnston, Olivia Rose. "A comparison of the stable isotopic ecology of eastern, western, and pre-human forest ecosystems in the South Island of New Zealand." Thesis, University of Canterbury. Biological Sciences, 2014. http://hdl.handle.net/10092/9445.
Повний текст джерелаYoshinaga, Marcos Yukio. "\"Origem e composição da matéria orgânica e a dinâmica da comunidade microbiana em sedimentos superficiais de ecossistemas marinhos da costa sudeste do Brasil\"." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/21/21131/tde-09042007-163722/.
Повний текст джерелаThe cycling of the organic matter (OM) in the marine environment is a key process in the global carbon cycle. Coastal sediments are important to the global carbon cycle, since they receive large inputs from both marine and terrestrial OM. The myriad of organic compounds and their spectrum of reactivity complicate the understanding of OM sources in coastal environments. In this work, we aimed to access the origin and composition of the OM (through lipid biomarkers) and the microbial dynamics (ATP method) in surface sediments of diverse marine ecosystems from the SE Brazilian coast: (i) the continental margin off Cabo Frio; (ii) the lagoonal system of Saquarema; (iii) coastal and shelf areas from Ubatuba; and (iv) the continental shelf adjacent to Santos estuary. The results showed a dominance of autochthonous OM, with a minor fraction of the OM derived from terrestrial sources and restricted to areas close to the coast. Oceanographic processes and environmental forces are crucial to the composition of sedimentary OM and are discussed for each of those ecosystems.
Shadwick, Elizabeth Henderson. "Carbon Cycling in Canadian Coastal Waters: Process Studies of the Scotian Shelf and the Southeastern Beaufort Sea." 2010. http://hdl.handle.net/10222/13107.
Повний текст джерелаPhD Thesis
Shao, Yuexiao. "Calibration of alkaline earth metal isotope tracers in semi-arid coastal environments." Thesis, 2021. https://hdl.handle.net/2440/133129.
Повний текст джерелаThesis (Ph.D.) -- University of Adelaide, School of Physical Sciences, 2021