Relevant bibliographies by topics / Biogeochemical modelling

Academic literature on the topic 'Biogeochemical modelling'

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Published: 4 June 2021
Last updated: 21 February 2023

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Journal articles on the topic "Biogeochemical modelling"

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Tskhai, А. А., and V. Yu Ageikov. "BIOGEOCHEMICAL CYCLES MODELLING IN RESERVOIRS ECOSYSTEMS." PROBLEMS OF ECOLOGICAL MONITORING AND ECOSYSTEM MODELLING 28, no. 4 (2017): 24–37. http://dx.doi.org/10.21513/0207-2564-2017-4-24-37.

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Scholes, R. J., and M. C. Scholes. "Applications of biogeochemical modelling in southern Africa." Progress in Physical Geography: Earth and Environment 21, no. 1 (March 1997): 102–12. http://dx.doi.org/10.1177/030913339702100106.

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Biogeochemical modelling is largely concerned with the cycling of carbon, nitrogen, phosphorus and sulphur in the biosphere. It offers a robust approach to modelling many aspects of ecosystem function at the regional scale, since it is not highly dependent on a detailed know ledge of species or organism-level processes. In southern Africa biogeochemical modelling has been used to provide new insight into the geographical distribution and underlying mechanisms of palatable (sweetveld) and unpalatable (sourveld) grasslands and high-herbivory and low- herbivory savannas. It has also been applied to the problem of estimating the emissions of trace gases and smoke particles from vegetation fires in the region, and suggests that the emissions are much lower than previously believed. Work in progress relates to the modelling of tropospheric ozone precursors produced by the soil and plants. Biogeochemical modelling has the potential to be an integrating tool, drawing together data collected at widely different scales in a way that allows hypotheses about the working of the biosphere to be rigorously tested.
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Duarte, P., B. Azevedo, M. Guerreiro, C. Ribeiro, R. Bandeira, A. Pereira, M. Falcão, D. Serpa, and J. Reia. "Biogeochemical modelling of Ria Formosa (South Portugal)." Hydrobiologia 611, no. 1 (July 29, 2008): 115–32. http://dx.doi.org/10.1007/s10750-008-9464-3.

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CLAIRE, M. W., D. C. CATLING, and K. J. ZAHNLE. "Biogeochemical modelling of the rise in atmospheric oxygen." Geobiology 4, no. 4 (December 2006): 239–69. http://dx.doi.org/10.1111/j.1472-4669.2006.00084.x.

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Warfvinge, Per, Julian Aherne, and Charlotta Walse. "Biogeochemical modelling of EXMAN research sites: A comparison." Forest Ecology and Management 101, no. 1-3 (February 1998): 143–53. http://dx.doi.org/10.1016/s0378-1127(97)00131-x.

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Hill, J., E. E. Popova, D. A. Ham, M. D. Piggott, and M. Srokosz. "Adapting to life: ocean biogeochemical modelling and adaptive remeshing." Ocean Science 10, no. 3 (May 9, 2014): 323–43. http://dx.doi.org/10.5194/os-10-323-2014.

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Abstract. An outstanding problem in biogeochemical modelling of the ocean is that many of the key processes occur intermittently at small scales, such as the sub-mesoscale, that are not well represented in global ocean models. This is partly due to their failure to resolve sub-mesoscale phenomena, which play a significant role in vertical nutrient supply. Simply increasing the resolution of the models may be an inefficient computational solution to this problem. An approach based on recent advances in adaptive mesh computational techniques may offer an alternative. Here the first steps in such an approach are described, using the example of a simple vertical column (quasi-1-D) ocean biogeochemical model. We present a novel method of simulating ocean biogeochemical behaviour on a vertically adaptive computational mesh, where the mesh changes in response to the biogeochemical and physical state of the system throughout the simulation. We show that the model reproduces the general physical and biological behaviour at three ocean stations (India, Papa and Bermuda) as compared to a high-resolution fixed mesh simulation and to observations. The use of an adaptive mesh does not increase the computational error, but reduces the number of mesh elements by a factor of 2–3. Unlike previous work the adaptivity metric used is flexible and we show that capturing the physical behaviour of the model is paramount to achieving a reasonable solution. Adding biological quantities to the adaptivity metric further refines the solution. We then show the potential of this method in two case studies where we change the adaptivity metric used to determine the varying mesh sizes in order to capture the dynamics of chlorophyll at Bermuda and sinking detritus at Papa. We therefore demonstrate that adaptive meshes may provide a suitable numerical technique for simulating seasonal or transient biogeochemical behaviour at high vertical resolution whilst minimising the number of elements in the mesh. More work is required to move this to fully 3-D simulations.
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Hill, J., E. E. Popova, D. A. Ham, M. D. Piggott, and M. Srokosz. "Adapting to life: ocean biogeochemical modelling and adaptive remeshing." Ocean Science Discussions 10, no. 6 (November 5, 2013): 1997–2051. http://dx.doi.org/10.5194/osd-10-1997-2013.

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Abstract. An outstanding problem in biogeochemical modelling of the ocean is that many of the key processes occur intermittently at small scales, such as the sub-mesoscale, that are not well represented in global ocean models. As an example, state-of-the-art models give values of primary production approximately two orders of magnitude lower than those observed in the ocean's oligotrophic gyres, which cover a third of the Earth's surface. This is partly due to their failure to resolve sub-mesoscale phenomena, which play a significant role in nutrient supply. Simply increasing the resolution of the models may be an inefficient computational solution to this problem. An approach based on recent advances in adaptive mesh computational techniques may offer an alternative. Here the first steps in such an approach are described, using the example of a~simple vertical column (quasi 1-D) ocean biogeochemical model. We present a novel method of simulating ocean biogeochemical behaviour on a vertically adaptive computational mesh, where the mesh changes in response to the biogeochemical and physical state of the system throughout the simulation. We show that the model reproduces the general physical and biological behaviour at three ocean stations (India, Papa and Bermuda) as compared to a high-resolution fixed mesh simulation and to observations. The simulations capture both the seasonal and inter-annual variations. The use of an adaptive mesh does not increase the computational error, but reduces the number of mesh elements by a factor of 2–3, so reducing computational overhead. We then show the potential of this method in two case studies where we change the metric used to determine the varying mesh sizes in order to capture the dynamics of chlorophyll at Bermuda and sinking detritus at Papa. We therefore demonstrate adaptive meshes may provide a~suitable numerical technique for simulating seasonal or transient biogeochemical behaviour at high spatial resolution whilst minimising computational cost.
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Holt, Jason, James Harle, Roger Proctor, Sylvain Michel, Mike Ashworth, Crispian Batstone, Icarus Allen, et al. "Modelling the global coastal ocean." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 367, no. 1890 (December 16, 2008): 939–51. http://dx.doi.org/10.1098/rsta.2008.0210.

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Shelf and coastal seas are regions of exceptionally high biological productivity, high rates of biogeochemical cycling and immense socio-economic importance. They are, however, poorly represented by the present generation of Earth system models, both in terms of resolution and process representation. Hence, these models cannot be used to elucidate the role of the coastal ocean in global biogeochemical cycles and the effects global change (both direct anthropogenic and climatic) are having on them. Here, we present a system for simulating all the coastal regions around the world (the Global Coastal Ocean Modelling System) in a systematic and practical fashion. It is based on automatically generating multiple nested model domains, using the Proudman Oceanographic Laboratory Coastal Ocean Modelling System coupled to the European Regional Seas Ecosystem Model. Preliminary results from the system are presented. These demonstrate the viability of the concept, and we discuss the prospects for using the system to explore key areas of global change in shelf seas, such as their role in the carbon cycle and climate change effects on fisheries.
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Sukhoveeva, O. E. "Problems of Modelling Carbon Biogeochemical Cycle in Agricultural Landscapes." Uchenye Zapiski Kazanskogo Universiteta. Seriya Estestvennye Nauki 162, no. 3 (2020): 473–501. http://dx.doi.org/10.26907/2542-064x.2020.3.473-501.

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Brigolin, D., VL Meccia, C. Venier, P. Tomassetti, S. Porrello, and R. Pastres. "Modelling biogeochemical fluxes across a Mediterranean fish cage farm." Aquaculture Environment Interactions 5, no. 1 (April 30, 2014): 71–88. http://dx.doi.org/10.3354/aei00093.

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Dissertations / Theses on the topic "Biogeochemical modelling"

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Rushby, Andrew. "Modelling biogeochemical controls on planetary habitability." Thesis, University of East Anglia, 2015. https://ueaeprints.uea.ac.uk/58503/.

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The length of a planet's `habitable period' is an important controlling factor on the evolution of life and of intelligent observers. This can be defined as the amount of time the surface temperature on the planet remains within defined `habitable' limits. Complex states of habitability derived from complex interactions between multiple factors may arise over the course of the evolution of an individual terrestrial planet with implications for long-term habitability and biosignature detection. The duration of these habitable conditions are controlled by multiple factors, including the orbital distance of the planet, its mass, the evolution of the host star, and the operation of any (bio)geochemical cycles that may serve to regulate planetary climate. A stellar evolution model was developed to investigate the control of increasing main-sequence stellar luminosity on the boundaries of the radiative habitable zone, which was then coupled with a zero-D biogeochemical carbon cycle model to investigate the operation of the carbonate-silicate cycle under conditions of varying incident stellar flux and planet size. The Earth will remain within habitable temperature limits for 6.34 Gyr (1.8 Gyr from present), but photosynthetic primary producers will experience carbon-starvation due to greatly increased terrestrial weathering from 5.38 Gyr (0.84 Gyr from present) onwards, with significant implications for planetary habitability. Planet mass was discovered to have a significant control on the length of the habitable period of Earth-like planets, but more data on the bulk density and atmospheric composition of newly-discovered exoplanets is required before definitive estimates of their long-term habitability can be made. Exoplanet case studies reveal habitable periods significantly longer than that of the Earth, possibly up to 80 Gyr in the case of planets in the orbit of M-dwarfs. Contemporary measures of habitability that rely strongly on surface temperatures are becoming obsolete, and a move towards the inclusion of integrated biogeochemical cycle models and the development of multiparameter habitability indices will strengthen contemporary understanding of the distribution and evolution of potentially habitable terrestrial worlds.
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Rocha, Carlos Rafael Vieira. "Biogeochemical modelling of the NW Iberian Margin." Master's thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/9576.

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Mestrado em Meteorologia e Oceanografia Física
A capacidade de fornecer dados oceanográficos sobre variáveis biológicas e químicas tem-se tornado num tema de relevância científica nos últimos anos. A procura por este tipo de informação provém de áreas e aplicações tão diversas como a investigação em ecossistemas marinhos, a monitorização da qualidade da água e o suporte à gestão do ambiente marinho e costeiro. Este trabalho consiste numa visão geral sobre a incorporação de um módulo biogeoquímico baseado em fluxos de azoto (NPZD) num modelo de circulação oceânica regional (ROMS) para a Margem NW Ibérica e para o período de 2007 a 2010. O estudo foca-se especialmente na validação do modelo, tanto empírica como objectiva, através da comparação entre os valores de clorofila-a simulados e os que constam numa extensa base de dados produzida pelo Ifremer/CERSAT, assim como na verificação da capacidade de reprodução de alguns fenómenos teoricamente expectáveis. A validação do modelo mostra que, embora existam algumas falhas, como uma subestimação geral dos valores superficiais de clorofila-a ou a antecipação ao início dos blooms primaveris, a resposta deste é satisfatória. Embora ainda exista muito a melhorar, é possível afirmar que está criado um modelo com acoplamento biogeoquímica-hidrodinâmica, completamente funcional e credível, com capacidade de simulação a uma escala inter-anual para a Margem NW Ibérica.
Providing oceanographic data on biological and chemical variables has become an issue of scientific concern over the last years. The demand for this kind of information arises from a range of fields and applications such as scientific research on marine ecosystems, monitoring of seawater quality and decision-making support for marine and coastal management. This work consists of an overview on the incorporation of a nitrogen-based (NPZD) biogeochemical module into a regional oceanic circulation model (ROMS) for the NW Iberian Margin for the 2007 to 2010 period. The study focuses especially in both empirical and objective model performance assessments through comparison of chlorophyll-a model outputs with an extensive satellite dataset produced by Ifremer/CERSAT and in the verification of the model ability to reproduce theoretically expected phenomena. The model validation shows that despite some flaws, as a general underestimation of chlorophyll-a surface values and an anticipation in the starting of the spring bloom, the model response is satisfactory. With still much to improve, its however possible to state that a fully-functional and reliable coupled biogeochemicalocean circulation model is available for the NW Iberian Margin, running at the inter-annual scale.
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Manizza, Manfredi. "Modelling phytoplankton-light feedback and its ocean biogeochemical implications." Thesis, University of East Anglia, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429677.

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Tedesco, Letizia <1978&gt. "Modelling coupled physical-biogeochemical processes in ice-covered oceans." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1996/1/letizia_tedesco_phd_thesis.pdf.

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The last decades have seen a large effort of the scientific community to study and understand the physics of sea ice. We currently have a wide - even though still not exhaustive - knowledge of the sea ice dynamics and thermodynamics and of their temporal and spatial variability. Sea ice biogeochemistry is instead largely unknown. Sea ice algae production may account for up to 25% of overall primary production in ice-covered waters of the Southern Ocean. However, the influence of physical factors, such as the location of ice formation, the role of snow cover and light availability on sea ice primary production is poorly understood. There are only sparse localized observations and little knowledge of the functioning of sea ice biogeochemistry at larger scales. Modelling becomes then an auxiliary tool to help qualifying and quantifying the role of sea ice biogeochemistry in the ocean dynamics. In this thesis, a novel approach is used for the modelling and coupling of sea ice biogeochemistry - and in particular its primary production - to sea ice physics. Previous attempts were based on the coupling of rather complex sea ice physical models to empirical or relatively simple biological or biogeochemical models. The focus is moved here to a more biologically-oriented point of view. A simple, however comprehensive, physical model of the sea ice thermodynamics (ESIM) was developed and coupled to a novel sea ice implementation (BFM-SI) of the Biogeochemical Flux Model (BFM). The BFM is a comprehensive model, largely used and validated in the open ocean environment and in regional seas. The physical model has been developed having in mind the biogeochemical properties of sea ice and the physical inputs required to model sea ice biogeochemistry. The central concept of the coupling is the modelling of the Biologically-Active-Layer (BAL), which is the time-varying fraction of sea ice that is continuously connected to the ocean via brines pockets and channels and it acts as rich habitat for many microorganisms. The physical model provides the key physical properties of the BAL (e.g., brines volume, temperature and salinity), and the BFM-SI simulates the physiological and ecological response of the biological community to the physical enviroment. The new biogeochemical model is also coupled to the pelagic BFM through the exchange of organic and inorganic matter at the boundaries between the two systems . This is done by computing the entrapment of matter and gases when sea ice grows and release to the ocean when sea ice melts to ensure mass conservation. The model was tested in different ice-covered regions of the world ocean to test the generality of the parameterizations. The focus was particularly on the regions of landfast ice, where primary production is generally large. The implementation of the BFM in sea ice and the coupling structure in General Circulation Models will add a new component to the latters (and in general to Earth System Models), which will be able to provide adequate estimate of the role and importance of sea ice biogeochemistry in the global carbon cycle.
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Tedesco, Letizia <1978&gt. "Modelling coupled physical-biogeochemical processes in ice-covered oceans." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1996/.

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The last decades have seen a large effort of the scientific community to study and understand the physics of sea ice. We currently have a wide - even though still not exhaustive - knowledge of the sea ice dynamics and thermodynamics and of their temporal and spatial variability. Sea ice biogeochemistry is instead largely unknown. Sea ice algae production may account for up to 25% of overall primary production in ice-covered waters of the Southern Ocean. However, the influence of physical factors, such as the location of ice formation, the role of snow cover and light availability on sea ice primary production is poorly understood. There are only sparse localized observations and little knowledge of the functioning of sea ice biogeochemistry at larger scales. Modelling becomes then an auxiliary tool to help qualifying and quantifying the role of sea ice biogeochemistry in the ocean dynamics. In this thesis, a novel approach is used for the modelling and coupling of sea ice biogeochemistry - and in particular its primary production - to sea ice physics. Previous attempts were based on the coupling of rather complex sea ice physical models to empirical or relatively simple biological or biogeochemical models. The focus is moved here to a more biologically-oriented point of view. A simple, however comprehensive, physical model of the sea ice thermodynamics (ESIM) was developed and coupled to a novel sea ice implementation (BFM-SI) of the Biogeochemical Flux Model (BFM). The BFM is a comprehensive model, largely used and validated in the open ocean environment and in regional seas. The physical model has been developed having in mind the biogeochemical properties of sea ice and the physical inputs required to model sea ice biogeochemistry. The central concept of the coupling is the modelling of the Biologically-Active-Layer (BAL), which is the time-varying fraction of sea ice that is continuously connected to the ocean via brines pockets and channels and it acts as rich habitat for many microorganisms. The physical model provides the key physical properties of the BAL (e.g., brines volume, temperature and salinity), and the BFM-SI simulates the physiological and ecological response of the biological community to the physical enviroment. The new biogeochemical model is also coupled to the pelagic BFM through the exchange of organic and inorganic matter at the boundaries between the two systems . This is done by computing the entrapment of matter and gases when sea ice grows and release to the ocean when sea ice melts to ensure mass conservation. The model was tested in different ice-covered regions of the world ocean to test the generality of the parameterizations. The focus was particularly on the regions of landfast ice, where primary production is generally large. The implementation of the BFM in sea ice and the coupling structure in General Circulation Models will add a new component to the latters (and in general to Earth System Models), which will be able to provide adequate estimate of the role and importance of sea ice biogeochemistry in the global carbon cycle.
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Bagnara, Maurizio <1985&gt. "Modelling biogeochemical cycles in forest ecosystems: a Bayesian approach." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7188/1/Bagnara_Maurizio_tesi.pdf.

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Forest models are tools for explaining and predicting the dynamics of forest ecosystems. They simulate forest behavior by integrating information on the underlying processes in trees, soil and atmosphere. Bayesian calibration is the application of probability theory to parameter estimation. It is a method, applicable to all models, that quantifies output uncertainty and identifies key parameters and variables. This study aims at testing the Bayesian procedure for calibration to different types of forest models, to evaluate their performances and the uncertainties associated with them. In particular,we aimed at 1) applying a Bayesian framework to calibrate forest models and test their performances in different biomes and different environmental conditions, 2) identifying and solve structure-related issues in simple models, and 3) identifying the advantages of additional information made available when calibrating forest models with a Bayesian approach. We applied the Bayesian framework to calibrate the Prelued model on eight Italian eddy-covariance sites in Chapter 2. The ability of Prelued to reproduce the estimated Gross Primary Productivity (GPP) was tested over contrasting natural vegetation types that represented a wide range of climatic and environmental conditions. The issues related to Prelued's multiplicative structure were the main topic of Chapter 3: several different MCMC-based procedures were applied within a Bayesian framework to calibrate the model, and their performances were compared. A more complex model was applied in Chapter 4, focusing on the application of the physiology-based model HYDRALL to the forest ecosystem of Lavarone (IT) to evaluate the importance of additional information in the calibration procedure and their impact on model performances, model uncertainties, and parameter estimation. Overall, the Bayesian technique proved to be an excellent and versatile tool to successfully calibrate forest models of different structure and complexity, on different kind and number of variables and with a different number of parameters involved.
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Bagnara, Maurizio <1985&gt. "Modelling biogeochemical cycles in forest ecosystems: a Bayesian approach." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7188/.

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Forest models are tools for explaining and predicting the dynamics of forest ecosystems. They simulate forest behavior by integrating information on the underlying processes in trees, soil and atmosphere. Bayesian calibration is the application of probability theory to parameter estimation. It is a method, applicable to all models, that quantifies output uncertainty and identifies key parameters and variables. This study aims at testing the Bayesian procedure for calibration to different types of forest models, to evaluate their performances and the uncertainties associated with them. In particular,we aimed at 1) applying a Bayesian framework to calibrate forest models and test their performances in different biomes and different environmental conditions, 2) identifying and solve structure-related issues in simple models, and 3) identifying the advantages of additional information made available when calibrating forest models with a Bayesian approach. We applied the Bayesian framework to calibrate the Prelued model on eight Italian eddy-covariance sites in Chapter 2. The ability of Prelued to reproduce the estimated Gross Primary Productivity (GPP) was tested over contrasting natural vegetation types that represented a wide range of climatic and environmental conditions. The issues related to Prelued's multiplicative structure were the main topic of Chapter 3: several different MCMC-based procedures were applied within a Bayesian framework to calibrate the model, and their performances were compared. A more complex model was applied in Chapter 4, focusing on the application of the physiology-based model HYDRALL to the forest ecosystem of Lavarone (IT) to evaluate the importance of additional information in the calibration procedure and their impact on model performances, model uncertainties, and parameter estimation. Overall, the Bayesian technique proved to be an excellent and versatile tool to successfully calibrate forest models of different structure and complexity, on different kind and number of variables and with a different number of parameters involved.
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Longo, Ana Rita Sá. "Biogeochemical response of Tagus Estuary to climate change : a modelling study." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15740.

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Mestrado em Ciências do Mar e das Zonas Costeiras
Estuaries are highly dynamic systems which may be modified in a climate change context. These changes can affect the biogeochemical cycles. Among the major impacts of climate change, the increasing rainfall events and sea level rise can be considered. This study aims to research the impact of those events in biogeochemical dynamics in the Tagus Estuary, which is the largest and most important estuary along the Portuguese coast. In this context a 2D biophysical model (MOHID) was implemented, validated and explored, through comparison with in-situ data. In order to study the impact of extreme rainfall events, which can be characterized by an high increase in freshwater inflow, three scenarios were set by changing the inputs from the main tributaries, Tagus and Sorraia Rivers. A realistic scenario considering one day of Tagus and Sorraia River extreme discharge, a scenario considering one day of single extreme discharge of the Tagus River and finally one considering the extreme runoff just from Sorraia River. For the mean sea level rise, two scenarios were also established. The first with the actual mean sea level value and the second considering an increase of 0.42 m. For the extreme rainfall events simulations, the results suggest that the biogeochemical characteristics of the Tagus Estuary are mainly influenced by Tagus River discharge. For sea level rise scenario, the results suggest a dilution in nutrient concentrations and an increase in Chl-a in specific areas.For both scenarios, the suggested increase in Chl-a concentration for specific estuarine areas, under the tested scenarios, can lead to events that promote an abnormal growth of phytoplankton (blooms) causing the water quality to drop and the estuary to face severe quality issues risking all the activities that depend on it.
Os estuários são sistemas altamente dinâmicos que se encontram em risco devido a eventos relacionados com as alterações climáticas. Estas alterações podem ter impactos nos ciclos biogeoquímicos. Entre esses efeitos podem considerar-se o aumento de períodos de chuvas torrenciais e o aumento do nível médio do mar. Assim, o objetivo deste trabalho é o estudo do impacto destes eventos na dinâmica biogeoquímica do Estuário do Tejo, que se trata do maior sistema estuarino da Península Ibérica. Neste contexto, foi implementado, validado e explorado através de comparação com dados in-situ, um modelo biofísico 2D (MOHID). De forma a avaliar a resposta biogeoquímica do estuário a períodos de chuvas torrenciais, caracterizadas por variações abruptas nas descargas fluviais dos principais tributários, Tejo e Sorraia, foram considerados três cenários. O primeiro considerando um dia de descarga extrema para os rios Tejo e Sorraia. O segundo, considerando uma descarga extrema apenas para o Rio Tejo e por último, considerando uma descarga apenas para o Rio Sorraia. Relativamente ao aumento do nível médio do mar, foram estabelecidos dois cenários, o primeiro com o nível médio do mar atual e o segundo considerando um aumento de 0.42 m, conforme estimado em estudos anteriores. Os resultados para a simulação das chuvas torrenciais indicam que as modificações previstas para os padrões biogeoquímicos dependem essencialmente da descarga do Rio Tejo. Para o cenário de aumento do nível médio do mar os resultados sugerem uma diminuição da concentração de nutrientes e um aumento de clorofila em áreas específicas. Em ambos os cenários, o aumento de clorofila em determinadas zonas do estuário, sugerido pelos resultados, pode levar a eventos que promovam um crescimento anormal de fitoplâncton fazendo com que a qualidade da água diminua e colocando em risco todas as atividades que dependem no Estuário do Tejo.
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Everett, Jason D. School of Biological Earth &amp Environmental Science UNSW. "Biogeochemical dynamics of an intermittently open estuary: a field and modelling study." Awarded by:University of New South Wales. School of Biological, Earth and Environmental Science, 2007. http://handle.unsw.edu.au/1959.4/30555.

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This thesis presents a combined modelling and observational study of an intermittently open and closed lake or lagoon (ICOLL) in south-eastern Australia. ICOLLs are a common, yet vulnerable type of estuary characterised by low freshwater inflow leading to a sand berm being formed across the entrance preventing oceanic flushing. The accumulation of nutrients during the closed phase, and the increased water residence time, can have detrimental effects on the estuary if the nutrient load cannot be assimilated. The general aim of this study was to develop a quantitative understanding of ecological processes in Intermittently Closed and Open Lakes or Lagoons (ICOLLs) through a combination of field work and ecological modelling. The field-based component of the studied was completed in Smiths Lake, NSW Australia. The field data shows that concentrations of NH3, NOx and Chlorophyll a in Smiths Lake gradually increases over time between the two studied opening events, before declining while the lake is open to the ocean. Phosphorus concentration is relatively low throughout both cycles. Of the 2 opening events, one was long (~ 3.5 months) and one was short (~3 weeks). Initially ammonia concentrations following this short open period were 2-4 times higher than the initial values from the previous 2 closures. The reduced open phase also resulted in more persistent stratification. The observations show that the duration of the open/closed phases will influence the physiochemical characteristics of the water column. A spatially resolved, eleven-box ecological model was developed for Smiths Lake. The process descriptions in the ecological model are based on a combination of physical and physiological limits to the processes of nutrient uptake, light capture by phytoplankton and predator/prey interactions. An inverse model is used to calculate mixing coefficients from salinity observations. When compared to field data, the ecological model obtains fits for salinity, nitrogen, phosphorus, chlorophyll a and zooplankton that are within 1.5 standard deviations of the mean of the field data. Simulations show that nutrient limitation (nitrogen and phosphorus) is the dominant factor limiting growth of the autotrophs during both the open and closed phases of the lake. The model is characterised by strong oscillations in phytoplankton and zooplankton abundance,typical of predator-prey cycles. A sensitivity analysis was completed using a simplified 1-box configuration, coupled with the existing ecological model. When small perturbations in the initial conditions of DIN, phytoplankton and zooplankton are implemented, the standard deviations of the state variables strongly attract to a declining oscillation, showing the variation between runs decreasing with time. The most sensitive parameters in the model were the feeding efficiency of small and large zooplankton, and the mortality of epiphytes and small zooplankton which all had normalised sensitivities of 1.28, 1.11, 1.01 and 1.05 respectively for a 10% change in parameter value. The non-linearity of the model is illustrated by increasing the percentage change of the parameter. For a 25% change in feeding efficiency of small and large zooplankton, the normalised sensitivity increased to 1.28 and 1.15 respectively, and for a 50% change, they increased further to 1.78 and 1.35 respectively. The ecological state variables were also sensitive to increased catchment loads and depths. The modelled system switches from seagrass dominated to algal dominated at loads over 10?? the current loads, with increased plankton biomass and suspended solids shading the seagrass. The spatially resolved ecological model is run for a variety of open/closed cycles to assess the impact of various opening regimes on the model state variables. The results indicate that Smiths Lake is capable of assimilating its current nutrient loads without persistent phytoplankton blooms or a decrease in seagrass biomass. When catchment loads are increased by 10?? or the duration of the lake open/closed cycle is increased there is a corresponding increase in seagrass biomass. In contrast, small and large phytoplankton both increase in biomass as the duration of the open phase increases. Small and large phytoplankton growth is generally limited by phosphorus, and seagrass growth is limited by nitrogen under normal catchment loads. Due to the shallow depths and low phytoplankton biomass, seagrass only becomes light limited when the nutrient and suspended solids loads are increased 10??. This switch to light limitation only decreases the biomass for short periods.
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Cropp, Roger Allan, and R. Cropp@griffith edu au. "A Biogeochemical Modelling Analysis of the Potential For Marine Ecosystems to Regulate Climate By the Production of Dimethylsulphide." Griffith University. Australian School of Environmental Studies, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030703.101310.

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The potential for life to control its environment was first suggested by Lovelock (1972). Charlson et al (1987) proposed a role for marine planktonic ecosystems in global climate regulation via the production and ventilation to the atmosphere of dimethylsulphide (DMS), a by-product of phytoplankton metabolism. Once in the atmosphere DMS contributes to the formation of cloud condensation nuclei, and increases the amount and brightness of cloud. This affects the albedo of the planet, reflecting more incident sunlight back into space, and cooling the earth. In common with many other 'hypotheses' regarding complex adaptive systems, the hypothesis proposed by Charlson et al (1987) is not experimentally testable. The production and ventilation to the atmosphere of DMS is the result of complex interactions between biological, chemical and physical processes. Consequently, increasing use is being made of mathematical models that simulate these processes to advance understanding of it (Archer et al. 2002). This study examines one of the fundamental mechanisms proposed by the Charlson et al (1987) hypothesis, that increasing global temperatures will lead to increased ventilation of DMS from the ocean to the atmosphere. The study develops one-dimensional biogeochemical models of DMS production by upper ocean ecosystems, based on the model proposed by Gabric et al. (1993b). The models are examined to elucidate their fundamental mathematical properties, and are subjected to sensitivity analysis to identify important processes and parameters. These investigations identify a simpler model that can reproduce the predictions of the Gabric et al. (1993b) model. Predictions derived from model simulations forced by climatologies of measured physical data are compared to a global database of measurements of sea surface DMS concentrations, and to observed depth profiles of DMS in the upper ocean. These comparisons confirm that all models are in good qualitative agreement with measured data. The fifteen global climate prediction models currently in use around the globe all predict substantial warming effects from the ventilation of anthropogenic carbon dioxide to the atmosphere. A simplified DMS model is calibrated to climatologies of Antarctic chlorophyll and DMS data and reproduces the data with great precision. The calibrated model is applied in global warming scenarios to 'test' the efficacy of the mechanism proposed by the Charlson et al (1987) hypothesis. This simulation provides evidence that the response predicted by the hypothesis is indeed feasible, and that substantial increases (up to 45%) in the ventilation of DMS to the atmosphere could be possible in some circumstances. The results of the modelling study provide impetus for further examination of field data. If couplings between marine biota and atmosphere are feasible, then they may be operating contemporarily, and may be detectable. Atmospheric DMS is oxidised to form aerosols (Miller et al. 2002) that influence the aerosol optical depth of the atmosphere. Archives of remote sensed ocean chlorophyll a concentration and aerosol optical depth are examined for evidence of the biologically mediated couplings. A clear coupling between aeolian dust and marine phytoplankton is evident from this analysis, suggesting that the deposition of dust from the atmosphere is a major factor controlling phytoplankton growth in many parts of the ocean. A second coupling between marine phytoplankton and atmospheric aerosols is also detected. This coupling is apparently not related to dust and is symmetrical about the equator, despite the substantial differences in the atmospheres and oceans of each hemisphere. It is speculated that this coupling may reflect the influence of the ventilation of DMS produced by marine phytoplankton on the atmosphere. This thesis provides new evidence supporting the important role of marine ecosystems in global climate regulation by the production of DMS. This evidence is principally obtained from a biogeochemical modelling approach, but is supported by analyses of empirical data. The concordance of results obtained from different approaches suggests that the contribution of marine ecosystems to global climate regulation is real, important and currently active.
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Books on the topic "Biogeochemical modelling"

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Gatti, Susanne. The rôle of sponges in high-Antarctic carbon and silicon cycling: A modelling approach = Die Rolle der Schwämme in hochantarktischen Kohlenstoff- und Silikatkreislauf : ein Modellierungsansatz. Bremerhaven: Alfred-Wegener-Institut für Polar- und Meeresforschung, 2002.

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Book chapters on the topic "Biogeochemical modelling"

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Haraldsson, Hördur V., and Harald Sverdrup. "Finding Simplicity in Complexity in Biogeochemical Modelling." In Environmental Modelling, 277–89. Chichester, UK: John Wiley & Sons, Ltd, 2013. http://dx.doi.org/10.1002/9781118351475.ch17.

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Andersen, V., H. G. Fransz, B. W. Frost, O. Klepper, F. Rassoulzadegan, F. Wulff, and Thomas R. Anderson. "Modelling Zooplankton." In Towards a Model of Ocean Biogeochemical Processes, 177–91. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-84602-1_8.

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Jackson, G., F. Joos, P. Nival, J. Rodriguez, U. Wolf, and P. Tett. "Modelling Particle Fluxes." In Towards a Model of Ocean Biogeochemical Processes, 227–36. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-84602-1_11.

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Matear, Richard J., and E. Jones. "Marine Biogeochemical Modelling and Data Assimilation." In Operational Oceanography in the 21st Century, 295–317. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-0332-2_12.

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Evans, Geoffrey T., and Michael J. R. Fasham. "Themes in Modelling Ocean Biogeochemical Processes." In Towards a Model of Ocean Biogeochemical Processes, 1–19. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-84602-1_1.

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Kratz, G. "Modelling the Global Carbon Cycle." In The Natural Environment and the Biogeochemical Cycles, 29–81. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-540-39209-5_2.

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Maier-Reimer, Ernst. "Design of a 3D Biogeochemical Tracer Model for the Ocean." In Modelling Oceanic Climate Interactions, 415–64. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-84975-6_12.

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Seibert, Petra. "Inverse modelling of sulfur emissions in Europe based on trajectories." In Inverse Methods in Global Biogeochemical Cycles, 147–54. Washington, D. C.: American Geophysical Union, 2000. http://dx.doi.org/10.1029/gm114p0147.

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Kiefer, Dale A. "Modelling Growth and Light Absorption in the Marine Diatom Skeletonema Costatum." In Towards a Model of Ocean Biogeochemical Processes, 93–121. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-84602-1_5.

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Moldan, Filip, Veronika Kronnäs, Anders Wilander, Erik Karltun, and Bernard J. Cosby. "Modelling Acidification and Recovery of Swedish Lakes." In Biogeochemical Investigations of Terrestrial, Freshwater, and Wetland Ecosystems across the Globe, 139–60. Dordrecht: Springer Netherlands, 2004. http://dx.doi.org/10.1007/978-94-007-0952-2_11.

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Conference papers on the topic "Biogeochemical modelling"

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Soetaert, Karline, Dick van Oevelen, Theodore E. Simos, George Psihoyios, Ch Tsitouras, and Zacharias Anastassi. "Modelling Marine Biological and Biogeochemical Data." In NUMERICAL ANALYSIS AND APPLIED MATHEMATICS ICNAAM 2011: International Conference on Numerical Analysis and Applied Mathematics. AIP, 2011. http://dx.doi.org/10.1063/1.3636664.

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"A systematic review of the treatment of phosphorus in biogeochemical and ecological models." In 20th International Congress on Modelling and Simulation (MODSIM2013). Modelling and Simulation Society of Australia and New Zealand (MSSANZ), Inc., 2013. http://dx.doi.org/10.36334/modsim.2013.h7.robson.

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"A 3D hydrodynamic-biogeochemical model for assessing artificial oxygenation in a riverine salt-wedge estuary." In 20th International Congress on Modelling and Simulation (MODSIM2013). Modelling and Simulation Society of Australia and New Zealand (MSSANZ), Inc., 2013. http://dx.doi.org/10.36334/modsim.2013.h7.hipsey.

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"Using a 3D hydrodynamic-biogeochemical model to compare estuarine nitrogen assimilation efficiency under anoxic and oxic conditions." In 19th International Congress on Modelling and Simulation. Modelling and Simulation Society of Australia and New Zealand (MSSANZ), Inc., 2011. http://dx.doi.org/10.36334/modsim.2011.i7.bruce.

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"A model of oxygen and nitrogen biogeochemical response to hydrodynamic regimes in the Yarra River estuary." In 21st International Congress on Modelling and Simulation (MODSIM2015). Modelling and Simulation Society of Australia and New Zealand, 2015. http://dx.doi.org/10.36334/modsim.2015.b7.bruce.

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Myrgiotis, Vasilis, and Mathew Williams. "Quantifying the carbon balance of managed grasslands in near-real time and at field scale by using satellite data and biogeochemical modelling." In Space, Satellites and Sustainability II, edited by Callum J. Norrie, Kristina Tamane, and Mathew Williams. SPIE, 2021. http://dx.doi.org/10.1117/12.2600856.

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Cummings, Richard, Andrew J. Baker, Trevor Sumerling, John Shevelan, and Amy Huntington. "The LLWR’s 2011 Environmental Safety Case." In ASME 2011 14th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2011. http://dx.doi.org/10.1115/icem2011-59135.

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The UK’s Low Level Waste Repository Ltd submitted an Environmental Safety Case (ESC) for the disposal of low-level waste to the Environment Agency on the 1st of May 2011. The ESC is a major submission that will decide the future use of the Repository and has major implications for the success of the UK’s LLW Strategy and decommissioning programme. This paper provides an overview of the work that has been carried out to support the submission. Key aspects of this ESC include: • detailed investigations of existing disposals, based on careful examination of existing records and other investigations, including interviews with former operational staff; • analysis of uncertainties in future disposals; • modelling of the biogeochemical evolution of the disposal system, which provides understanding of the evolution of pH, Eh and gas generation and thence underpinning for radionuclide releases in groundwater and gas; • development of a 3-D groundwater flow model, calibrated against observed heads and with a detailed representation of the engineered features; • analysis of coastal erosion and its impacts; • a major focus on optimisation based on detailed technical studies; • a conclusion that existing disposals do not require remediation; • the choice of a concrete vault design with permeable side walls designed to avoid bathtubbing after the end of management control; • a comprehensive set of assessment calculations, including thorough analysis of uncertainties, which demonstrate consistency with the Environment Agency’s risk and dose guidance levels; • revision of the LLWR’s WAC, based in part on the use of the ‘sum of fractions’ approach; • the use of a safety case document structure that emphasises key safety arguments in a Level 1 document and provides supporting evidence in a series of Level 2 documents; • the provision of a Level 2 document that describes in detail how each aspect of the regulatory guidance has been addressed. In the future, the 2011 ESC will be maintained using a formal system of change control. It will be used as a tool for decision making concerning the future development of the LLWR and waste acceptance.
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Reports on the topic "Biogeochemical modelling"

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Taucher, Jan, and Markus Schartau. Report on parameterizing seasonal response patterns in primary- and net community production to ocean alkalinization. OceanNETs, November 2021. http://dx.doi.org/10.3289/oceannets_d5.2.

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We applied a 1-D plankton ecosystem-biogeochemical model to assess the impacts of ocean alkalinity enhancement (OAE) on seasonal changes in biogeochemistry and plankton dynamics. Depending on deployment scenarios, OAE should theoretically have variable effects on pH and seawater pCO2, which might in turn affect (a) plankton growth conditions and (b) the efficiency of carbon dioxide removal (CDR) via OAE. Thus, a major focus of our work is how different magnitudes and temporal frequencies of OAE might affect seasonal response patterns of net primary productivity (NPP), ecosystem functioning and biogeochemical cycling. With our study we aimed at identifying a parameterization of how magnitude and frequency of OAE affect net growth rates, so that these effects could be employed for Earth System Modell applications. So far we learned that a meaningful response parameterization has to resolve positive and negative anomalies that covary with temporal shifts. As to the intricacy of the response patterns, the derivation of such parameterization is work in progress. However, our study readily provides valuable insights to how OAE can alter plankton dynamics and biogeochemistry. Our modelling study first focuses at a local site where time series data are available (European Station for Time series in the Ocean Canary Islands ESTOC), including measurements of pH, concentrations of total alkalinity, dissolved inorganic carbon (DIC), chlorophyll-a and dissolved inorganic nitrogen (DIN). These observational data were made available by Andres Cianca (personal communication, PLOCAN, Spain), Melchor Gonzalez and Magdalena Santana Casiano (personal communication, Universidad de Las Palmas de Gran Canaria). The choice of this location was underpinned by the fact that the first OAE mesocosm experiment was conducted on the Canary Island Gran Canaria, which will facilitate synthesizing our modelling approach with experimental findings. For our simulations at the ESTOC site in the Subtropical North Atlantic we found distinct, non-linear responses of NPP to different temporal modes of alkalinity deployment. In particular, phytoplankton bloom patterns displayed pronounced temporal phase shifts and changes in their amplitude. Notably, our simulations suggest that OAE can have a slightly stimulating effect on NPP, which is however variable, depending on the magnitude of OAE and the temporal mode of alkalinity addition. Furthermore, we find that increasing alkalinity perturbations can lead to a shift in phytoplankton community composition (towards coccolithophores), which even persists after OAE has stopped. In terms of CDR, we found that a decrease in efficiency with increasing magnitude of alkalinity addition, as well as substantial differences related to the timing of addition. Altogether, our results suggest that annual OAE during the right season (i.e. physical and biological conditions), could be a reasonable compromise in terms of logistical feasibility, efficiency of CDR and side-effects on marine biota. With respect to transferability to global models, the complex, non-linear responses of biological processes to OAE identified in our simulations do not allow for simple parameterizations that can easily adapted. Dedicated future work is required to transfer the observed responses at small spatiotemporal scales to the coarser resolution of global models.
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