Relevant bibliographies by topics / Biogeochemical techniques

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Book chapters
  4. Conference papers
  5. Reports

Academic literature on the topic 'Biogeochemical techniques'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Biogeochemical techniques"

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Hahn, A., P. Rosén, P. Kliem, C. Ohlendorf, and B. Zolitschka. "Comparative study of infrared techniques for fast biogeochemical sediment analyses." Geochemistry, Geophysics, Geosystems 12, no. 10 (October 2011): n/a. http://dx.doi.org/10.1029/2011gc003686.

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Samuiloviene, Aurelija, Marco Bartoli, Stefano Bonaglia, Ulisse Cardini, Irma Vybernaite-Lubiene, Ugo Marzocchi, Jolita Petkuviene, Tobia Politi, Anastasija Zaiko, and Mindaugas Zilius. "The Effect of Chironomid Larvae on Nitrogen Cycling and Microbial Communities in Soft Sediments." Water 11, no. 9 (September 16, 2019): 1931. http://dx.doi.org/10.3390/w11091931.

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The combination of biogeochemical methods and molecular techniques has the potential to uncover the black-box of the nitrogen (N) cycle in bioturbated sediments. Advanced biogeochemical methods allow the quantification of the process rates of different microbial processes, whereas molecular tools allow the analysis of microbial diversity (16S rRNA metabarcoding) and activity (marker genes and transcripts) in biogeochemical hot-spots such as the burrow wall or macrofauna guts. By combining biogeochemical and molecular techniques, we analyzed the role of tube-dwelling Chironomus plumosus (Insecta, Diptera) larvae on nitrification and nitrate reduction processes in a laboratory experiment with reconstructed sediments. We hypothesized that chironomid larvae stimulate these processes and host bacteria actively involved in N-cycling. Our results suggest that chironomid larvae significantly enhance the recycling of ammonium (80.5 ± 48.7 µmol m−2 h−1) and the production of dinitrogen (420.2 ± 21.4 µmol m−2 h−1) via coupled nitrification–denitrification and the consumption of water column nitrates. Besides creating oxygen microniches in ammonium-rich subsurface sediments via burrow digging and ventilation, chironomid larvae serve as hot-spots of microbial communities involved in N-cycling. The quantification of functional genes showed a significantly higher potential for microbial denitrification and nitrate ammonification in larvae as compared to surrounding sediments. Future studies may further scrutinize N transformation rates associated with intimate macrofaunal–bacteria associations.
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Hutchins, DA, WX Wang, MA Schmidt, and NS Fisher. "Dual-labeling techniques for trace metal biogeochemical investigations in aquatic plankton communities." Aquatic Microbial Ecology 19 (1999): 129–38. http://dx.doi.org/10.3354/ame019129.

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Ward, Ben A., Marjorie A. M. Friedrichs, Thomas R. Anderson, and Andreas Oschlies. "Parameter optimisation techniques and the problem of underdetermination in marine biogeochemical models." Journal of Marine Systems 81, no. 1-2 (April 2010): 34–43. http://dx.doi.org/10.1016/j.jmarsys.2009.12.005.

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Ethier, Danielle M., Christopher J. Kyle, T. Kurt Kyser, and Joseph J. Nocera. "Variability in the growth patterns of the cornified claw sheath among vertebrates: implications for using biogeochemistry to study animal movement." Canadian Journal of Zoology 88, no. 11 (November 2010): 1043–51. http://dx.doi.org/10.1139/z10-073.

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We review the role of biogeochemical signatures, such as stable isotopes and trace elements, in the cornified claw tissue as a means of studying movement and foraging behaviour of vertebrates because this approach is noninvasive and can capture contemporary and historic signatures. Because biogeochemical techniques are still relatively new in studies of animal movement, we are only beginning to understand how the growth patterns of the cornified claw sheath may affect our ability to interpret the biogeochemical signals in these tissues. To move towards resolving this, we review the morphology of the epidermal cornified claw sheath in several taxa that illustrate substantial variation in growth patterns both between taxa and between individual distinct claw regions. For instance, in mammalian claws, deposition of keratinizing cells from the epidermis is nonlinear because the claw tip is composed of old and new cornified epidermal cells, whereas the cornified blade horn covering the claw’s lateral walls is deposited continuously and without assortment, providing unbroken time-series data. We also consider patterns of growth in mammalian hooves, as well as reptilian, avian, and amphibian cornified claw sheaths, and address the need for expanded research in this field. We conclude this synthesis by describing a noninvasive technique for monitoring growth rates in a model mammal, the American badger ( Taxidea taxus (Schreber, 1777)), and provide guidelines for future sampling of claw keratin, which will improve our ability to back-calculate the time of biogeochemical integration into this tissue.
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Smith, Pete, Fabrizio Albanito, Madeleine Bell, Jessica Bellarby, Sergey Blagodatskiy, Arindam Datta, Marta Dondini, et al. "Systems approaches in global change and biogeochemistry research." Philosophical Transactions of the Royal Society B: Biological Sciences 367, no. 1586 (January 19, 2012): 311–21. http://dx.doi.org/10.1098/rstb.2011.0173.

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Systems approaches have great potential for application in predictive ecology. In this paper, we present a range of examples, where systems approaches are being developed and applied at a range of scales in the field of global change and biogeochemical cycling. Systems approaches range from Bayesian calibration techniques at plot scale, through data assimilation methods at regional to continental scales, to multi-disciplinary numerical model applications at country to global scales. We provide examples from a range of studies and show how these approaches are being used to address current topics in global change and biogeochemical research, such as the interaction between carbon and nitrogen cycles, terrestrial carbon feedbacks to climate change and the attribution of observed global changes to various drivers of change. We examine how transferable the methods and techniques might be to other areas of ecosystem science and ecology.
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Rennert, Thilo, Kai U. Totsche, Katja Heister, Michael Kersten, and Jürgen Thieme. "Advanced spectroscopic, microscopic, and tomographic characterization techniques to study biogeochemical interfaces in soil." Journal of Soils and Sediments 12, no. 1 (August 30, 2011): 3–23. http://dx.doi.org/10.1007/s11368-011-0417-5.

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Chen, X. D., K. E. Dunfield, T. D. Fraser, S. A. Wakelin, A. E. Richardson, and L. M. Condron. "Soil biodiversity and biogeochemical function in managed ecosystems." Soil Research 58, no. 1 (2020): 1. http://dx.doi.org/10.1071/sr19067.

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A complex combination of environmental, biological, chemical, and physical properties and processes determine soil biodiversity and its relationship to biogeochemical functions and ecosystem services. Vegetation, land-use, and land management, in turn, influence diversity and function in the soil ecosystem. The objective of this review was to assess how different land-use systems (crop production, animal production, and planted forest) affect soil biodiversity, and how consequent changes in soil biodiversity influence energy (carbon) and nutrient dynamics. Deficiencies in understanding relationships between soil biodiversity and biogeochemical function in managed ecosystems are highlighted, along with the need to investigate how diversity influences specific processes across different functional groups and trophic levels. The continued development and application of molecular techniques and data informatics with descriptive approaches will contribute to advancing our understanding of soil biodiversity and function in managed agricultural and forest ecosystems.
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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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Dissertations / Theses on the topic "Biogeochemical techniques"

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Huang, Xiaoyan, and n/a. "Biogeochemical techniques for environmental monitoring and mineral exploration : a case study at the Temora Gold Mine." University of Canberra. School of Resource, Environmental & Heritage Sciences, 1998. http://erl.canberra.edu.au./public/adt-AUC20060726.170405.

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Biogeochemistry has been utilized successfully in Australia as a regional or fellow-up geochemical exploration techniques in the arid terranes of Australia. This Master's study is based on the biogeochemistry approach, which relies on the chemical analysis of plant tissues to obtain information on the geology and geochemistry of the underlying rocks. The project involved the systematic sampling and chemical analysis of plant materials and the supporting soils to establish the suitability of using particular tree species for environmental monitoring and their potential as a sample medium in geochemical exploration in the vicinity of the Temora Gold Mine, NSW, Australia. Working on 168 plant tissues (leaves, twigs and bark) in 54 plants species from 8 families at the three sites of background area, mineralized area and tailings area, and 54 supporting soil samples from three strata of 0-5 cm, 20-30 cm, and 30-40 cm, found that there was a good agreement between soil geochemistry and plant geochemistry on the result of a strong geochemical association between Au and As. The As-Au pattern was suggestive of the presence of the Au-As mineralization. Black cypress pine (Callitris endlicheri) LEAVES show a higher ratio of Asminjn/Aumin in the mineralized area than ASbkg/Aubkg in the background area, up to 7 times. The research finding suggests that the LEAVES of Black cypress pine (Callitris endlicheri) have a potential to be a biogeochemical sample medium as better indicators for Au. Golden wattle (Acacia pycnantha) BARK and Yellow box (E. melliodora) BARK appear to be better indicators for Au but more research is required. The most occurrence of anomalies of As, Au, Sb, Cu and Fe were found in Red box (E. polyanthemos) BARK. Red box (E. polyanthemos) BARK may have the potential to be an Au indicator in the area when Red box (E. polyanthemos) is present. Results on test-tolerant plants show that Eucalyptus species: Red box (E. polyanthemos), Coral gum (E. torquata), and Yellow box (E. melliodora) have a higher rate of uptake trace elements from the tailings soils. Therefore, Eucalyptus family generally adapted to metal-rich soils and can be used as cleaning-up indicators and environmental monitors for the tailings area of metal contaminated soils in the Temora Gold Mine.
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Neuhuber, Stephanie Maria Ulrike. "In situ measurements of redox chemical species with amperometric techniques to investigate the dynamics of biogeochemical processes in aquatic systems." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/25737.

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Butenschon, Momme <1973&gt. "Numerical simulations of the coastal marine ecosystem dynamics: integration techniques and data assimilation in a complex physical-biogeochemical model." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/552/.

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Weeber, Russell C. "Nutrient addition and the use of stable isotope techniques in wetlands of the Interlake Region of Manitoba, Canada." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22825.

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This study examines the relationship between nutrient additions and algae and invertebrate productivity in a nutrient-poor wetland of the Interlake Region of Manitoba, Canada. Alfalfa hay was added to experimental enclosures in May 1992. Alfalfa additions were made in unprocessed and ground forms and consisted of three treatments: ground low, whole low, and whole high. Dissolved oxygen, surface water nutrients, algae standing crop, and invertebrate production were monitored at open marsh sites and in treatment and control enclosures during 1992 and 1993. Stable $ sp{13}$C, $ sp{15}$N and $ sp{34}$S isotope ratios were determined for the alfalfa additions, and for surface water, algae, macrophytes, sediments and invertebrates.
In general, the effects of nutrient additions were confined to 1992. Treatment enclosure dissolved oxygen levels decreased immediately following fertilization, recovering in the low treatments by early June. Low oxygen conditions persisted in whole high enclosures throughout most of 1992. Dissolved and suspended nutrient concentrations, and phytoplankton chlorophyll a increased but, with the exception of dissolved N, were soon lost from the water column. Treatment enclosure epiphytic algae increased while epipelon did not respond to fertilization. The primary effect of fertilization on invertebrate production was an increase in treatment enclosure chironomid larvae during 1992. As with productivity measures, stable isotope ratio values suggested a temporary presence of alfalfa nutrients in the enclosed food webs. Only the isotope ratios of metaphytic algae and snails collected during August 1992 indicated an incorporation of alfalfa nutrients.
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Fernández, Gómez Cristal. "New insights on the biogeochemical cycle of mercury in freshwater environments. Development and application of the DGT technique for bioavailability assessment and studies of methylmercury photodegradation." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/279241.

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Mercury (Hg) is naturally present in the Earth’s crust, however the historical use of this metal by the human being has spread and increased its presence in the environment. Both inorganic and organic species can be found in aquatic ecosystems, which are very sensitive to Hg pollution. In anoxic waters and sediments, sulphate-reducing bacteria can convert inorganic Hg into methylmercury (MeHg), a very toxic organic form which has the ability to bioaccumulate and biomagnify throughout trophic chains. Thus, to assess the risk associated to Hg pollution, the development of techniques to monitor Hg levels in water is necessary, as well as investigating MeHg elimination pathways. In this doctoral thesis, two aspects related to the biogeochemical cycle of Hg in freshwater were addressed. On one hand, a passive sampling technique –Diffusive Gradients in Thin films (DGT)– was developed both for determination of total Hg (THg) and MeHg in freshwater. Apart from providing a time-average Hg concentration, these samplers are able to measure the labile fraction of Hg, since they supposedly mimic biological membranes. Thus, the DGT technique is considered a good monitoring tool to estimate the bioavailability of Hg in water. On the other hand, MeHg photodegradation in freswhwaters dominated by dissolved organic matter (DOM) was studied. Regarding the DGT technique, several preliminary tests were carried out both at the laboratory and in the field to test the validity of a commercial type of samplers to measure the labile dissolved Hg in continental waters. Later, the performance of this commercial type was compared to that of two in-house manufactured samplers; both of them with the same receiving gel consisting of a resin with 3-mercaptopropyl groups embedded in a polyacrylamide gel, but one with an agarose gel (A-DGT) and the other with polyacrylamide gel (P-DGT) as the diffusive layer. The uptake kinetics of Hg(II) and MeHg, both in the absence and in the presence of DOM, were studied. The diffusion coefficient, D, of Hg in the DGT diffusive layer varied among Hg species and also depended on the absence/presence of DOM in the solution. This confirms the need to use the Hg species of interest and simulate the characteristics of the water to be sampled when performing the DGT calibration if the aim is to accurately measure the labile Hg fraction. The P-DGT was chosen as the most appropriate to determine both THg and MeHg in natural waters. Thereby, this type of sampler was used in a case study to assess the removal, methylation and lability of Hg(II) in a experimental scale plant for wastewater treatment consisting in several constructed wetlands with different conformation in series. With respect to the MeHg photodegradation issue, this phenomenon was studied in waters from a lake-wetland gradient in the boreal Sweden. The influence of DOM on this process by attenuating light, forming reactive oxygen species and binding MeHg to its thiol groups to form complexes, was examined. It was observed that the desmethylation rate constant (kpd Full Spectrum) varied significantly among the three studied waters, but the wavelength-specific rate constants (kpdPAR, kpdUVA and kpdUVB) were indistinguishable. Therefore, kpd PAR, kpd UVA and kpd UVB can be considered universal, at least in waters dominated by DOM and in which MeHg is complexed by organic thiols, if the photon fluxes of PAR, UVA and UVB radiation are separately determined and the wavelength-specific light attenuation by DOM is corrected for. Furthermore, the relationship between the photodegradation and bioavailability of MeHg was examined in an experiment involving different types of natural and artificial freshwater, but no apparent connection was observed between them.
En aquesta tesi doctoral s'aborden dos aspectes relacionats amb al cicle biogeoquímic del Hg en aigües continentals. Per una banda, es va desenvolupar un sistema de mostreig passiu denominat gradients de difusió en capa fina (DGT), per la determinació del Hg total i del MeHg en fase aquosa. Aquests mostrejadors proporcionen la concentració mitjana de Hg durant el temps de mostreig i mesuren la fracció làbil de Hg. Per tant, la tècnica de DGT pot ser considerada una bona eina per avaluar la biodisponibilitat de Hg a l’aigua. D'altra banda, es va estudiar la fotodegradació de MeHg en aigües continentals. Pel que fa a la tècnica DGT, es van dur a terme diverses proves preliminars tant al laboratori com en el camp per provar la validesa d'un tipus comercial de mostrejador per mesurar el Hg dissolt i col•loidal làbil en aigua dolça. Aquest es va comparar amb dos tipus de mostrejadors DGT manufacturats al laboratori (A-DGT i P-DGT). Es van estudiar les cinètiques d’acumulació de Hg(II) i MeHg tant en absència com en presència de DOM. El P-DGT va ser escollit com el més apropiat per determinar ambdós THg i MeHg en aigües naturals i va ser utilitzat en un estudi de cas per avaluar l'eliminació, metilació i labilitat de Hg(II) en una aiguamoll construït a escala experimental pel tractament d’aigües residuals urbanes. La fotodegradació de MeHg va ser estudiada en aigües d'un gradient llac-aiguamoll en la Suècia boreal; i es va evaluar la influència de DOM en el procés. Es va observar que la constant de velocitat de fotodesmetilació (kpd Full Spectrum) va variar significativament entre les aigües estudiades, però les constants específiques per a cada longitud d'ona (kpdPAR, kpdUVA and kpdUVB) van ser indistingibles. Per això, kpdPAR, kpdUVA and kpdUVB poden ser considerades universals en aigües amb un alt contingut en DOM i on el MeHg estigui complexat per grups tiol orgànics. Finalment, amb la utilització de la tècnica DGT es va estudiar la possible influència que pot existir entre la fotodegradació i la biodisponibilitat de MeHg en diversos tipus d'aigues dolces naturals i artificials, però no es va observar cap connexió aparent entre elles.
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Di, Tullo Pamela. "Dynamique du cycle biogéochimique du sélénium en écosystèmes terrestres : rétention et réactivité dans le sol, rôle de la végétation." Thesis, Pau, 2015. http://www.theses.fr/2015PAUU3013/document.

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Ce travail s’inscrit dans la problématique d’évaluation de sûreté préalable au possible stockage de déchets radioactifs HAVL en couches géologiques profondes. Afin de consolider les modèles de prédiction à longue terme des risques associés à une contamination potentielle de la biosphère par le 79Se, la biogéochimie du sélénium stable a été explorée, en visant dans un premier temps un éclairage sur la dynamique du cycle global de Se dans un écosystème forestier en terme de stock et flux annuels. Suite aux résultats de la première partie, qui suggèrent l’importance du sol et son pool organique dans le cycle global de Se, deux études basées sur l’utilise des traceurs isotopique stables ont été ensuite menées afin de clarifier les processus impliqués (i) dans la rétention et la réactivité de Se dans les sols et (ii) dans la bio-incorporation de Se inorganique dans la biomasse des plantes au sein d’une fraction organique
This work was performed in the frame of the safety assessment program prior to the possible construction of an underground repository for nuclear waste (HAVL). To consolidate risk assessment models associated to a potential 79Se biosphere contamination, biogeochemistry of stable selenium was investigated, aiming firstly to highlight the dynamics of Se cycling in a forest ecosystem, in terms of inventories and annual fluxes. Consequently to these first results, which suggest a clay role of soil and its organic pool in the global Se cycle, two studies based on the use of isotopically enriched tracers were further carried out in order to clarify the processes involved in (i) Se retention and reactivity in soils and (ii) incorporation of inorganic Se within organic pool of vegetal biomass
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Zhang, Weitao. "Application of Bayesian Inference Techniques for Calibrating Eutrophication Models." Thesis, 2008. http://hdl.handle.net/1807/17238.

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This research aims to integrate mathematical water quality models with Bayesian inference techniques for obtaining effective model calibration and rigorous assessment of the uncertainty underlying model predictions. The first part of my work combines a Bayesian calibration framework with a complex biogeochemical model to reproduce oligo-, meso- and eutrophic lake conditions. The model accurately describes the observed patterns and also provides realistic estimates of predictive uncertainty for water quality variables. The Bayesian estimations are also used for appraising the exceedance frequency and confidence of compliance of different water quality criteria. The second part introduces a Bayesian hierarchical framework (BHF) for calibrating eutrophication models at multiple systems (or sites of the same system). The models calibrated under the BHF provided accurate system representations for all the scenarios examined. The BHF allows overcoming problems of insufficient local data by “borrowing strength” from well-studied sites. Both frameworks can facilitate environmental management decisions.
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Book chapters on the topic "Biogeochemical techniques"

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Huygens, Dries, Mark Trimmer, Tobias Rütting, Christoph Müller, Catherine M. Heppell, Katrina Lansdown, and Pascal Boeckx. "Biogeochemical Nitrogen Cycling in Wetland Ecosystems: Nitrogen-15 Isotope Techniques." In Methods in Biogeochemistry of Wetlands, 553–91. Madison, WI, USA: American Society of Agronomy and Soil Science Society of America, 2015. http://dx.doi.org/10.2136/sssabookser10.c30.

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Mukul, Sharif A., Md Abdul Halim, and John Herbohn. "Forest Carbon Stock and Fluxes: Distribution, Biogeochemical Cycles, and Measurement Techniques." In Encyclopedia of the UN Sustainable Development Goals, 1–16. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-319-71065-5_23-1.

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Mukul, Sharif A., Md Abdul Halim, and John Herbohn. "Forest Carbon Stock and Fluxes: Distribution, Biogeochemical Cycles, and Measurement Techniques." In Encyclopedia of the UN Sustainable Development Goals, 361–76. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-319-95981-8_23.

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Bruhwiler, Lori, Pieter Tans, and Michel Ramonet. "A time-dependent assimilation and source retrieval technique for atmospheric tracers." In Inverse Methods in Global Biogeochemical Cycles, 265–77. Washington, D. C.: American Geophysical Union, 2000. http://dx.doi.org/10.1029/gm114p0265.

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Xu, Zhihong. "Unravelling the Biogeochemical Cycles of Carbon and Nutrients in Forest Ecosystems: Innovative Approaches with Advanced Stable Isotope and NMR Techniques as well as Soil Chemical and Physical Methods." In Molecular Environmental Soil Science at the Interfaces in the Earth’s Critical Zone, 17–19. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-05297-2_5.

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Wang, Shengrui, and Zhihao Wu. "The Coupled Fe–S–P Biogeochemical Mechanism for P-Release and Sulfide Microniche in Sediments Assessed by DGT–CID Technique (Dianchi Lake)." In DGT-based Measurement of Phosphorus in Sediment Microzones and Rhizospheres, 93–105. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-0721-7_5.

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"Techniques for Studying Stocks and Fluxes." In The Biogeochemical Cycle of Silicon in the Ocean, 7–25. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119136880.ch2.

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Boyanov, Maxim I., and Kenneth M. Kemner. "Application of Synchrotron X-ray Absorption Spectroscopy and Microscopy Techniques to the Study of Biogeochemical Processes." In Analytical Geomicrobiology, 238–61. Cambridge University Press, 2019. http://dx.doi.org/10.1017/9781107707399.010.

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Pathak, Prasad, and Stephen Whalen. "Using Geospatial Techniques to Analyze Landscape Factors Controlling Ionic Composition of Arctic Lakes, Toolik Lake Region, Alaska." In Geographic Information Systems, 130–50. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-2038-4.ch012.

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The impacts of climate change on landscapes in arctic Alaska are evident in terms of permafrost melting, frequent thermokarst activity, and the occurrence of more broadleaf vegetation. These changes may alter natural biogeochemical cycles of ions along with major nutrients and affect ionic compositions of lakes, as they are connected with the landscapes. However, the nature of the connectivity between lakes and landscapes in this region is not yet explored. The authors propose that geospatial analysis of landscape properties along with observed lake ion concentrations will enable an understanding of the currently existing landscape controls over ion inputs into the lakes. For the watersheds of 41 lakes in the Arctic Foothills region of Alaska, spatial properties of natural vegetation communities expressed in terms of percentage, shape complexity, and patch density metrics were derived using satellite data. Regression analyses were performed for concentration of ions as well as conductivity in lake water where the spatial metrics along with lake physical properties, lake order, and glacial till age categories were used as predicting variables in the regression. Landscape metrics for major land covers i.e., Percentage of Moist Acidic Tundra (MAT) and Moist Non-acidic Tundra (MNT) were the major predicting variables for concentration of several ions.
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Bianchi, Thomas S. "Characterization of Organic Matter." In Biogeochemistry of Estuaries. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780195160826.003.0018.

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In chapter 8, a general overview was provided on the dominant sources of organic matter in estuarine systems. In general, estuarine organic matter is derived from a multitude of natural and anthropogenic allochthonous and autochthonous sources that originate across a freshwater to seawater continuum. Knowledge of sources, reactivity, and fate of organic matter are critical in understanding the role of estuarine and coastal systems in global biogeochemical cycles (Simoneit, 1978; Hedges and Keil, 1995; Bianchi and Canuel, 2001). Due to a wide diversity of organic matter sources and the dynamic mixing that occurs in estuarine systems, it remains a significant challenge in determining the relative importance of these source inputs to biogeochemical cycling in the water column of sediments. Temporal and spatial variability in organic matter inputs adds further to the complexity in understanding these environments. In recent years there have been significant improvements in our ability to distinguish between organic matter sources in estuaries using tools such as elemental, isotopic (bulk and compound/class specific), and chemical biomarker methods. This chapter will provide a general overview of the biochemistry of dominant organic compounds in organic matter and the techniques used to distinguish them in estuarine systems. The abundance and ratios of important elements in biological cycles (e.g., C, H, N, O, S, and P) provide the basic foundation of information on organic matter cycling. For example, concentrations of total organic carbon (TOC) provide the most important indicator of organic matter since approximately 50% of most organic matter consists of C. As discussed in chapter 8, TOC in estuaries is derived from a broad spectrum of sources with very different structural properties and decay rates. Consequently, while TOC provides essential information on spatial and temporal dynamics of organic matter it lacks any specificity to source or age of the material. When bulk C information is combined with additional elemental information, as in the case of the C-to-N ratio, basic source information can be inferred about algal and terrestrial source materials (see review, Meyers, 1997). The broad range of C:N ratios across divergent sources of organic matter in the biosphere demonstrate how such a ratio can provide an initial proxy for determining source information.
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Conference papers on the topic "Biogeochemical techniques"

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Wei, Yuli, Xi Nie, Li Zhang, Huimin Yao, Haiyan Mao, and Jiasong Fang. "The Unseen Majority of Microorganisms in Hadal Trenche Sediments Revealed by Molecular and Biogeochemical Techniques." In Goldschmidt2020. Geochemical Society, 2020. http://dx.doi.org/10.46427/gold2020.2840.

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Jansik, Danielle, Dawn M. Wellman, Shas V. Mattigod, Lirong Zhong, Yuxin Wu, Martin Foote, Fred Zhang, and Susan Hubbard. "Foam: Novel Delivery Technology for Remediation of Vadose Zone Environments." In ASME 2011 14th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2011. http://dx.doi.org/10.1115/icem2011-59019.

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Deep vadose zone environments can be a primary source and pathway for contaminant migration to groundwater. These environments present unique characterization and remediation challenges that necessitate scrutiny and research. The thickness, depth, and intricacies of the deep vadose zone, combined with a lack of understanding of the key subsurface processes (e.g., biogeochemical and hydrologic) affecting contaminant migration, make it difficult to create validated conceptual and predictive models of subsurface flow dynamics and contaminant behavior across multiple scales. These factors also make it difficult to design and deploy sustainable remedial approaches and monitor long-term contaminant behavior after remedial actions. Functionally, methods for addressing contamination must remove and/or reduce transport of contaminants. This problem is particularly challenging in the arid western United States where the vadose zone is hundreds of feet thick, rendering transitional excavation methods exceedingly costly and ineffective. Delivery of remedial amendments is one of the most challenging and critical aspects for all remedy-based approaches. The conventional approach for delivery is through heterogeneous deep vadose zone environments present hydrologic and geochemical challenges that limit the effectiveness. Because the flow of solution infiltration is dominantly controlled by gravity and suction, injected liquid preferentially percolates through highly permeable pathways, by-passing low-permeability zones that frequently contain the majority of contamination. Moreover, the wetting front can readily mobilize and enhance contaminant transport to the underlying aquifer prior to stabilization. Development of innovative in-situ technologies may be the only means to meet remedial action objectives and long-term stewardship goals. Surfactants can be used to lower the liquid surface tension and create stabile foams, which readily penetrate low permeability zones. Although surfactant foams have been used for subsurface mobilization efforts in the oil and gas industry, thus far the concept of using foams as a delivery mechanism for transporting remedial amendments into deep vadose zone environments to stabilize metal and long-lived radionuclide contaminants has not been explored. Foam flow can be directed by pressure gradients, rather than being dominated by gravity; and foam delivery mechanisms limit the volume of water (< 5% vol.) required for remedy delivery and emplacement, thus mitigating contaminant mobilization. We will present the results of a numerical modeling and integrated laboratory-/intermediate-scale investigation to simulate, develop, demonstrate, and monitor (i.e., advanced geophysical techniques and advanced predictive biomarkers) foam-based delivery of remedial amendments to remediate metals and radionuclides in vadose zone environments.
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Reports on the topic "Biogeochemical techniques"

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Lloyd, Jonathan R. Novel Imaging Techniques, Integrated with Mineralogical, Geochemical and Microbiological Characterization to Determine the Biogeochemical Controls.... Office of Scientific and Technical Information (OSTI), June 2005. http://dx.doi.org/10.2172/893406.

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Lloyd, Jonathan R. Novel Imaging Techniques, Integrated with Mineralogical, Geochemical and Microbiological Characterization to Determine the Biogeochemical Controls.... Office of Scientific and Technical Information (OSTI), June 2004. http://dx.doi.org/10.2172/893690.

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Jonathan R. Lloyd. Novel imaging techniques, integrated with mineralogical, geochemical and microbiological characterizations to determine the biogeochemical controls on technetium mobility in FRC sediments. Office of Scientific and Technical Information (OSTI), February 2009. http://dx.doi.org/10.2172/946786.

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