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Littérature scientifique sur le sujet « Biogeochemical effects »

Auteur : Grafiati

Publié le 25 janvier 2025

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Articles de revues sur le sujet "Biogeochemical effects"

Chi, Zhi-Lai, et Guang-Hui Yu. « Nanozyme-mediated elemental biogeochemical cycling and environmental effects ». Science China Earth Sciences 64, n^o 7 (3 juin 2021) : 1015–25. http://dx.doi.org/10.1007/s11430-020-9756-5.

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Luís, Ana Teresa, Manuela Teixeira, Nuno Durães, Raquel Pinto, Salomé F. P. Almeida, Eduardo Ferreira da Silva et Etelvina Figueira. « Extremely acidic environment : Biogeochemical effects on algal biofilms ». Ecotoxicology and Environmental Safety 177 (août 2019) : 124–32. http://dx.doi.org/10.1016/j.ecoenv.2019.04.001.

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Fuhrman, Jed A. « Marine viruses and their biogeochemical and ecological effects ». Nature 399, n^o 6736 (juin 1999) : 541–48. http://dx.doi.org/10.1038/21119.

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Portnoy, J. W., et A. E. Giblin. « BIOGEOCHEMICAL EFFECTS OF SEAWATER RESTORATION TO DIKED SALT MARSHES ». Ecological Applications 7, n^o 3 (août 1997) : 1054–63. http://dx.doi.org/10.1890/1051-0761(1997)007[1054:beosrt]2.0.co;2.

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Wang, Fushun, Stephen C. Maberly, Baoli Wang et Xia Liang. « Effects of dams on riverine biogeochemical cycling and ecology ». Inland Waters 8, n^o 2 (3 avril 2018) : 130–40. http://dx.doi.org/10.1080/20442041.2018.1469335.

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Lenton, Timothy M., et Stuart J. Daines. « Matworld - the biogeochemical effects of early life on land ». New Phytologist 215, n^o 2 (24 novembre 2016) : 531–37. http://dx.doi.org/10.1111/nph.14338.

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Zepp, R. G., T. V. Callaghan et D. J. Erickson. « Effects of enhanced solar ultraviolet radiation on biogeochemical cycles ». Journal of Photochemistry and Photobiology B : Biology 46, n^o 1-3 (octobre 1998) : 69–82. http://dx.doi.org/10.1016/s1011-1344(98)00186-9.

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Herrmann, R., R. Stottlemyer, J. C. Zak, R. L. Edmonds et H. Van Miegroet. « BIOGEOCHEMICAL EFFECTS OF GLOBAL CHANGE ON U.S. NATIONAL PARKS1 ». JAWRA Journal of the American Water Resources Association 36, n^o 2 (avril 2000) : 337–46. http://dx.doi.org/10.1111/j.1752-1688.2000.tb04272.x.

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Davies-Barnard, Taraka, Andy Ridgwell, Joy Singarayer et Paul Valdes. « Quantifying the influence of the terrestrial biosphere on glacial–interglacial climate dynamics ». Climate of the Past 13, n^o 10 (26 octobre 2017) : 1381–401. http://dx.doi.org/10.5194/cp-13-1381-2017.

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Abstract. The terrestrial biosphere is thought to be a key component in the climatic variability seen in the palaeo-record. It has a direct impact on surface temperature through changes in surface albedo and evapotranspiration (so-called biogeophysical effects) and, in addition, has an important indirect effect through changes in vegetation and soil carbon storage (biogeochemical effects) and hence modulates the concentrations of greenhouse gases in the atmosphere. The biogeochemical and biogeophysical effects generally have opposite signs, meaning that the terrestrial biosphere could potentially have played only a very minor role in the dynamics of the glacial–interglacial cycles of the late Quaternary. Here we use a fully coupled dynamic atmosphere–ocean–vegetation general circulation model (GCM) to generate a set of 62 equilibrium simulations spanning the last 120 kyr. The analysis of these simulations elucidates the relative importance of the biogeophysical versus biogeochemical terrestrial biosphere interactions with climate. We find that the biogeophysical effects of vegetation account for up to an additional −0.91 °C global mean cooling, with regional cooling as large as −5 °C, but with considerable variability across the glacial–interglacial cycle. By comparison, while opposite in sign, our model estimates of the biogeochemical impacts are substantially smaller in magnitude. Offline simulations show a maximum of +0.33 °C warming due to an increase of 25 ppm above our (pre-industrial) baseline atmospheric CO2 mixing ratio. In contrast to shorter (century) timescale projections of future terrestrial biosphere response where direct and indirect responses may at times cancel out, we find that the biogeophysical effects consistently and strongly dominate the biogeochemical effect over the inter-glacial cycle. On average across the period, the terrestrial biosphere has a −0.26 °C effect on temperature, with −0.58 °C at the Last Glacial Maximum. Depending on assumptions made about the destination of terrestrial carbon under ice sheets and where sea level has changed, the average terrestrial biosphere contribution over the last 120 kyr could be as much as −50 °C and −0.83 °C at the Last Glacial Maximum.

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Bush, T., I. B. Butler, A. Free et R. J. Allen. « Redox regime shifts in microbially mediated biogeochemical cycles ». Biogeosciences 12, n^o 12 (17 juin 2015) : 3713–24. http://dx.doi.org/10.5194/bg-12-3713-2015.

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Abstract. Understanding how the Earth's biogeochemical cycles respond to environmental change is a prerequisite for the prediction and mitigation of the effects of anthropogenic perturbations. Microbial populations mediate key steps in these cycles, yet they are often crudely represented in biogeochemical models. Here, we show that microbial population dynamics can qualitatively affect the response of biogeochemical cycles to environmental change. Using simple and generic mathematical models, we find that nutrient limitations on microbial population growth can lead to regime shifts, in which the redox state of a biogeochemical cycle changes dramatically as the availability of a redox-controlling species, such as oxygen or acetate, crosses a threshold (a "tipping point"). These redox regime shifts occur in parameter ranges that are relevant to the present-day sulfur cycle in the natural environment and the present-day nitrogen cycle in eutrophic terrestrial environments. These shifts may also have relevance to iron cycling in the iron-containing Proterozoic and Archean oceans. We show that redox regime shifts also occur in models with physically realistic modifications, such as additional terms, chemical states, or microbial populations. Our work reveals a possible new mechanism by which regime shifts can occur in nutrient-cycling ecosystems and biogeochemical cycles, and highlights the importance of considering microbial population dynamics in models of biogeochemical cycles.

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Thèses sur le sujet "Biogeochemical effects"

Miller, Bradley W. « Long-term Effects of Fertilization on Phosphorus Biogeochemical Pools in Forest Soils ». Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/37386.

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Southern pines are typically limited by nitrogen (N) and phosphorus (P) availability in the soil environment. While the absolute quantities of P in forests soils may be large, the concentration of inorganic P in the soil solution is typically very small (&60; 0.01 mg L&178;-1). A onetime application of just 56 kg P ha&178;-1 can substantially increase growth of pine stands over a 20 year rotation (Pritchett and Comerford, 1982&59; Allen et al., 1990). Phosphorus fertilization of Pinus radiata in New Zealand has also shown long-term effects on labile P pools in the soil which improved stand growth during the subsequent rotations (Ballard, 1978&59; Gentle et al., 1986). Identifying and quantifying the biologically available P pools in the soil environment will help foresters in making site-specific P fertilizer prescriptions. I examined soil phosphorus pools using the Hedley sequential fractionation procedure and Mehlich-3 soil tests in a long-term loblolly pine (Pinus taeda L.) fertilization trial from four sites in the Atlantic and Gulf Coastal Plains. After 22 years, fertilization effects were limited to the surface depths. Mehlich-3 extractable P was largest in the soil surface (0-10 cm) of the fertilized treatments plots. Hedley labile and moderately labile P pools were also largest in the soil surface and decreased with depth. Results from the Hedley fractionation procedure suggested that the Virginia site has a large pool of organic P in the soil surface. Organic P pools can represent 20-90&37; of the total P present in most mineral soils increasing with the age of the soil (Condron et al., 2005). This increase in organic P pool suggests that biological cycling becomes more important as the stand develops (Wells and Jorgensen 1975). I used solution 31P nuclear magnetic resonance (NMR) spectroscopy to characterize organic P extracted with NaOH-EDTA in the surface of a Paleaquults from coastal Virginia. Total NaOH-EDTA extractable P was significantly larger in the fertilized treatment. Concentrations ranged from 0.1 mg P L&178;-1 in the control plots to 5.1 mg P L&178;-1 in fertilized plots. The surface soils in both treatments were dominated by inorganic orthophosphate. Monoester P compounds were the only organic P compounds detected and were present in very low quantities. The significant increase of NaOH/EDTA extractable P in the soil surface of the VA site suggested there has been a beneficial long-term effect of fertilization similar to the observations from the Mehlich-3 soil test. Results from oxalate loading experiments on ligand exchangeable versus dissolvable P pools in the bulk soil suggested that the long-term effect of P fertilization increased oxalate dissolvable P pools. Plants and microbes have evolved a variety of mechanisms to increase P uptake in low P soil environments. These mechanisms include changes in root morphology and architecture, preferential root growth into high P microsites, the secretion of low-molecular-mass organic acids (LMMOA), and uptake via symbiotic relationships (Fox and Comerford, 1992b&59; Raghothama, 1999&59; Hinsinger, 2001&59; Raghothama, 2005). Results from soil samples taken from the ectomycorrhizal rhizosphere found that loblolly pine mycorrhizal roots modified the soil environment, possibly making recalcitrant P more available. In addition, the long-term effect of fertilization was a 396&37; increase in biologically available P. Fertilization increased loblolly pine volume growth by 57 m&185;3 ha and increased the P content in the litter layer by 118&37;. After the stand was harvested and replanted, mineralization of the litter layer may also increase soil P pools. Results from this long-term fertilization experiment in the Coastal Plain province of Virginia have demonstrated that there has been a significant increase in soil (33.6 kg P ha&178;-1) and biologically available P pools (3.0 kg P ha&178;-1).
Ph. D.

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Murphy, Anna Elizabeth. « Effects of commercial clam aquaculture on biogeochemical cycling in shallow coastal ecosystems ». W&M ScholarWorks, 2015. https://scholarworks.wm.edu/etd/1539616787.

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As the bivalve aquaculture industry expands worldwide, there is growing interest in its use to mitigate coastal eutrophication, the increased supply of organic matter to an ecosystem. Bivalves influence eutrophication by exerting `top-down' control on primary production through feeding while simultaneously influencing local `bottom-up' effects by increasing nutrient recycling. Additionally, nitrogen (N) is removed via harvest and potentially enhanced denitrification (DNF); however, DNF competes for nitrate (NO3-) with dissimilatory nitrate reduction to ammonium (DNRA), an N retention process. Seasonal in situ flux measurements in Cherrystone Inlet, VA, demonstrated that clam aquaculture sediments are a source of ammonium (NH4+), derived from clam excretion and microbial mineralization of clam biodeposits. Macroalgae, which proliferate on predator-exclusion nets utilized by the US clam industry temporarily sequester this regenerated N. Clam cultivation influences eutrophication locally by providing N in excess of macroalgal N demand, facilitating increased macroalgal production. Experiments investigated the competition between DNF and DNRA within clam sediments. at clam beds in Cherrystone Inlet, DNRA was more favored over DNF than at uncultivated sediments, likely due to the availability of labile organic carbon supplied by clams, low nitrate availability, and sulfidic sediments. However, a comparative study across clam aquaculture sites in the Sacca di Goro, Italy, where Ruditapes philippinarum are cultured, and on the Eastern Shore, VA, where Mercenaria mercenaria are cultured, revealed that the competition between DNF and DNRA is highly dependent on the environment and particularly the relative availability of labile carbon to NO3-. DNF exceeded DNRA at sites in the Sacca di Goro with elevated water column NO3-, concurrent with high abundances of a burrowing amphipod (Corophium sp.) that promoted nitrification. DNRA exceeded DNF at the VA sites and in the eastern region of the Sacca di Goro, where clam biomass was high, water column NO3" low, and sediments were generally reduced. Variability in rates across sites highlights the challenge in generalizing about the role of DNF in enhancing N removal across all clam aquaculture locations. An ecosystem-scale C and N budget was constructed for Cherrystone Inlet to understand the influence of clam cultivation on energy flow and eutrophication at a basin-wide scale. Although clam cultivation occupied only 3% of the Inlet's surface area, the clams filtered a volume equivalent to 7-44% of the system daily. Annually, N regeneration at the clam beds was ~3-fold higher than N removed by harvest. Due to the short water residence time, low watershed N load, and close vicinity of clam beds to the mouth of the Inlet, cultivated clams are likely subsidized by phytoplankton from the Chesapeake Bay. Thus, the N regenerated at the clam beds, which fuels macroalgal production would not be present in the system without facilitation by the cultured clams. This study demonstrates that although clams may dampen eutrophication by removing phytoplankton from the water column, high densities of clams can facilitate rapid N turnover through excretion and DNRA, fueling macroalgae, a form of eutrophication. The effect of clam aquaculture on N removal and subsequently organic matter supply is highly dependent on environmental conditions and clam cultivation practices, as well as the scale considered. at a large-scale (e.g. Chesapeake Bay) clam aquaculture is a net sink for N through harvest, however this study suggests that clam aquaculture may increase N and organic matter supply (i.e. macroalgae) on a basin-wide scale (e.g. Cherrystone Inlet).

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Iwasaki, Kenta. « Effects of bedrock groundwater dynamics on hydro-biogeochemical processes in granitic headwater catchments ». Kyoto University, 2018. http://hdl.handle.net/2433/232152.

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Tritschler, Sarah J. « Biogeochemical Processes and Seasonal Effects in Flow-Through Mesocosm Reactors Simulating Constructed Wetlands ». Wright State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=wright1198819178.

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Lancaster, Nicole N. M. « Effects of salinity on biogeochemical processes and methylmercury production in freshwater wetland sediments ». View electronic thesis, 2008. http://dl.uncw.edu/etd/2008-3//r1/lancastern/nicolelancaster.pdf.

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Wilson, Cullen. « Biogeochemical Effects of Lime-Treated Biosolids Amendments on Soils in a Northeastern Forested Ecosystem ». Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/WilsonC2008.pdf.

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Heinle, Moritz. « The effects of light, temperature and nutrients on coccolithophores and implications for biogeochemical models ». Thesis, University of East Anglia, 2013. https://ueaeprints.uea.ac.uk/48676/.

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Coccolithophores are one of the important groups of phytoplankton in the global oceans, which makes it important to know how this group will react to changes in their environment due to climate change. Modellers already recognized their importance and included this group independently in global biogeochemical models. This study assesses the effect of light, temperature and nutrient availability on five coccolithophores, performing a range of laboratory experiments. The results of these experiments were then used to change the parameterisation of coccolithophores in the global biogeochemical model PlankTOM10. Furthermore, the model was validated in two ways, using a database of coccolithophore biomass measurements from the field and measurements of surface calcium carbonate derived from satellite data. Temperature effects on growth depend a great deal on the coccolithophore species. E. huxleyi (both, a subtropical and a temperate strain) and P. carterae grew best around 20°C, whereas G. oceanica and C. leptoporus had optimum temperatures above 25°C and still grew well at the maximum temperature tested in the experiments. E. huxleyi was the species with the highest growth rates (μmax=0.98 for the subtropical strain and μmax=0.97 for the temperate), followed closely by G. oceanica and C. leptoporus (μmax=0.91 in both species). P. carterae (μmax=0.77) had a noticeably lower maximum growth rate than the other coccolithophores. An inverse relationship with growth rate was found for all measured cellular components (POM, PIC, Chl a) as well as for cell volume in P. carterae. Coccolithophores are good competitors at high light intensities, having optimum growth light intensities above 180 μmol photons m-2 s-1. The temperate strain of E. huxleyi and the species G. oceanica showed the lowest optima at 350 μmol photon III m-2 s-1. C. leptoporus (Iopt=500 μmol photon m-2 s-1) and P. carterae (Iopt=600 μmol photon m-2 s-1) had higher optimum growth light intensities and the subtropical strain of E. huxleyi (Iopt=900 μmol photon m-2 s-1) grew best at the highest light intensity applied in this study. Only one strain of E. huxleyi showed light inhibition in its photosynthetic activity that was well above the detection limit in P-I curves up to 2000 μmol photons m-2 s-1. Apart from a well-known decrease in Chl a/C ratio with increasing light intensity, little variation in the concentration of cellular components (POM, PIC) was observed. Nutrient experiments were carried out in a chemostat with two strains of E. huxleyi and one G. oceanica. Phosphorus limitation led to an increase in cell volume (112- 157%) and particulate organic carbon (21-54%) in E. huxleyi and G. oceanica, relative to cultures grown under nitrogen limitation. Comparison of uptake rates for phosphate and nitrate with other phytoplankton groups showed that both species are very good competitors for phosphate and relatively poor competitors for nitrate. The initial PlankTOM10 model simulation overestimated biomass compared with a new observational database, and underestimated surface calcium carbonate compared with satellite data. Changing the coccolithophore parameterisation in PlankTOM10, based on the laboratory results, did not lead to significant improvements relative to the observations. However, the response of the model to the parameter changes could be explained either directly from the changed parameters, or indirectly from changes in the model ecosystem.

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Colson, Christopher G. Lockaby Bruce Graeme. « Biogeochemical effects of silviculture management on intermittant streamside management zones in the coastal plain of Alabama ». Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SPRING/Forestry_and_Wildlife_Sciences/Thesis/Colson_Christopher_20.pdf.

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Trentman, Matthew T. « Biotic and abiotic effects on biogeochemical fluxes across multiple spatial scales in a prairie stream network ». Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/19750.

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Master of Science
Division of Biology
Walter K. Dodds
Understanding the variability of ecological processes across spatial scales is a central issue in ecology, because increasing scale is often associated with increasing complexity. In streams, measurements of biogeochemical fluxes are important for determining ecosystem health and the downstream delivery of nutrients, but are often collected at scales with benthic areas measured in spatial areas from ~10 cm[superscript]2 to ~100 m[superscript]2 (referred to here as patch and reach, respectively), which are smaller than the scale that management decisions are made. Both biotic and abiotic factors will be important when attempting to predict (i.e. scale) biogeochemical rates, but few studies have simultaneously measured rates and their primary drivers at different spatial scales. In the first chapter, I used a conceptual scaling framework to evaluate the ability to additively scale biogeochemical rates by comparing measurements of ecosystem respiration (ER) and gross primary production (GPP) from patch to reach-scales across multiple sites over a two-year period in a prairie stream. Patch-scale measurements with and without fish (biotic factors) and abiotic factors measured simultaneously with metabolic rates suggest that abiotic conditions are stronger drivers of these rates. Patch-scale rates significantly overestimated reach rates for ER and GPP after corrections for habitat heterogeneity, temperature and light, and a variety of stream substrata compartments. I show the importance of determining abiotic and biotic drivers, which can be determined through observational or experimental measurements, when building models for scaling biogeochemical rates. In the second chapter, I further examined patch-scale abiotic and biotic drivers of multiple biogeochemical rates (ER, GPP, and ammonium uptake) using path analyses and data from chapter 2. Total model-explained variance was highest for ER (65% as R[superscript]2) and lowest for GPP and ammonium uptake (38%). Fish removal directly increased ammonium uptake, while all rates were indirectly affected by fish removal through changes in either FBOM and /or algal biomass. Significant paths of abiotic factors varied with each model. Large-scale processes (i.e. climate change and direct anthropogenic disturbances), and local biotic and abiotic drivers should all be considered when attempting to predict stream biogeochemical fluxes at varying spatial scales.

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Spencer, David. « The Effects of Oceanographic Drivers on the Catchability of Spanner Crabs ». Thesis, Griffith University, 2018. http://hdl.handle.net/10072/380993.

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The world’s largest commercial spanner crab (Ranina ranina) fishery, situated on the east coast of Australia, is showing signs of a fishery-wide population decline. This trend has become ubiquitous in many global fishery stocks and is most commonly attributed to anthropogenic pressure and the rapidly changing climate. Thus, the importance of better understanding how commercially-important fishery species thrive in their immediate and surrounding environment is imperative. Catchability is an important parameter used to describe the relationship between catch rates and the abundance of the target species. Variations in catchability are often attributed to fluctuations in environmental and oceanographic conditions in the species’ preferred habitat. Earlier research had suggested several hydrodynamic and hydrographic parameters affect the catchability of spanner crabs. However, a review of the literature (thesis chapter 2) indicated the need for further investigations, particularly on the specific oceanographic processes responsible for these effects. This thesis examines the effects of several oceanographic parameters on spanner crab catch rates at a range of spatiotemporal scales. At large spatial scales (100:500 km) over several years, higher surface chlorophyll-a concentrations, relative to the range of chlorophyll-a observed in each management region, were correlated with lower catch rates in fishing grounds close to the coast and bays. Additionally, region-specific processes responsible for bringing oceanic waters into spanner crab fishing grounds were associated with an increase in catch rates. The link between oceanic water and increased catch rates was further supported by a more localised study (~100 km) that showed cooler ambient temperatures, occasionally attributed to wind-driven upwelling, increased catch rates of spanner crabs at both seasonal and shorter (days-months) temporal scales. At various fishing locations off the Gold Coast, Australia, the effects of current speed, direction and turbidity were examined to determine how specific conditions (day to day) and changes in conditions during soak times (hours) affected catch rates. The most significant finding from this work suggests that catch rates of spanner crabs benefit from a specific range of current speeds (~0.07-0.12 m.s-1), and current speeds exhibiting a large amount of variability may trigger a spike in catch rates over a period of hours. Results from this work show current speed can help explain short-term catch rate anomalies that are currently deemed “random” in stock assessment models. Incorporating environmental and oceanographic parameters into stock assessment models has been an ever-evolving challenge for fishery management. Depending on the region-specific oceanographic and coastal processes, various remotely-sensed oceanographic parameters are also useful in explaining catch rates. The most significant outcomes from this thesis indicate bottom temperature, alongshore wind stress, and bottom current speed are suitable in explaining variability in spanner crab catch rates. A coupled hydrodynamic and biogeochemical model capable of resolving and predicting fluctuations in these oceanographic parameters will help support studies in other areas of the Australian fishery and smaller fisheries in the Indo-Pacific, help improve the accuracy of stock assessment models, and greatly benefit the economic efficiency of commercial crabbing operations.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
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Livres sur le sujet "Biogeochemical effects"

Howe, John T. Biogeochemical cycling in the ocean. Moffett Field, Calif : National Aeronautics and Space Administration, Ames Research Center, 1986.

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Braun, Christopher L. Water-level variations and their effects on tree growth and mortality and on the biogeochemical system at the phytoremediation demonstration site in Fort Worth, Texas, 1996-2003. Reston, Va : U.S. Dept. of the Interior, U.S. Geological Survey, 2004.

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L, Braun Christopher, Geological Survey (U.S.) et Aeronautical Systems Center (U.S.). Environmental Management Directorate, dir. Water-level variations and their effects on tree growth and mortality and on the biogeochemical system at the phytoremediation demonstration site in Fort Worth, Texas, 1996-2003. [Reston, Va.] : U.S. Dept. of the Interior, U.S. Geological Survey, 2004.

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L, Braun Christopher, Geological Survey (U.S.) et Aeronautical Systems Center (U.S.). Environmental Management Directorate., dir. Water-level variations and their effects on tree growth and mortality and on the biogeochemical system at the phytoremediation demonstration site in Fort Worth, Texas, 1996-2003. [Reston, Va.] : U.S. Dept. of the Interior, U.S. Geological Survey, 2004.

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L, Braun Christopher, Geological Survey (U.S.) et Aeronautical Systems Center (U.S.). Environmental Management Directorate., dir. Water-level variations and their effects on tree growth and mortality and on the biogeochemical system at the phytoremediation demonstration site in Fort Worth, Texas, 1996-2003. Reston, Va : U.S. Dept. of the Interior, U.S. Geological Survey, 2004.

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Mannion, Antoinette M. Global environmental change : The disruption of biogeochemical cycles / A.M. Mannion. Reading, U.K : Department of Geography, University of Reading, 1998.

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R, Wollast, Mackenzie Fred T. 1934-, Chou Lei 1953-, North Atlantic Treaty Organization. Scientific Affairs Division. et NATO Advanced Research Workshop on Interactions of C,N,P, and S Biogeochemical Cycles (1991 : Melreux, Belgium), dir. Interactions of C, N, P, and S biogeochemical cycles and global change. Berlin : Springer-Verlag, 1993.

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Paul, Bennett. Earth, the incredible recycling machine. New York : Thomson Learning, 1993.

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Lukashev, K. I. Trevogi i nadezhdy : Izmeni͡a︡i͡u︡shchai͡a︡si͡a︡ biosfera. Minsk : "Nauka i tekhnika", 1987.

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Chapitres de livres sur le sujet "Biogeochemical effects"

Boucher, Olivier. « Biogeochemical Effects and Climate Feedbacks of Aerosols ». Dans Atmospheric Aerosols, 247–69. Dordrecht : Springer Netherlands, 2015. http://dx.doi.org/10.1007/978-94-017-9649-1_11.

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Falkowski, Paul G. « The Oceanic Photosynthetic Engine : Origins, Evolution, and Role in Global Biogeochemical Cycles ». Dans Photosynthesis : Mechanisms and Effects, 3941–47. Dordrecht : Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-3953-3_916.

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Lorenz, Klaus, et Rattan Lal. « Biogeophysical and Biogeochemical Climate Effects of Organic Agriculture ». Dans Organic Agriculture and Climate Change, 177–200. Cham : Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-17215-1_4.

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Helbling, E. W., V. Villafañe, M. Ferrario et O. Holm-Hansen. « Effects of Ultraviolet Radiation on Marine Phytoplankton ». Dans Primary Productivity and Biogeochemical Cycles in the Sea, 514. Boston, MA : Springer US, 1992. http://dx.doi.org/10.1007/978-1-4899-0762-2_42.

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Van Klinken, Gert J., Mike P. Richards et Bert E. M. Hedges. « An Overview of Causes for Stable Isotopic Variations in Past European Human Populations : Environmental, Ecophysiological, and Cultural Effects ». Dans Biogeochemical Approaches to Paleodietary Analysis, 39–63. Boston, MA : Springer US, 2002. http://dx.doi.org/10.1007/0-306-47194-9_3.

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Bergman, Magda J. N., et Han J. Lindeboom. « Natural Variability and the Effects of Fisheries in the North Sea : Towards an Integrated Fisheries and Ecosystem Management ? » Dans Biogeochemical Cycling and Sediment Ecology, 173–84. Dordrecht : Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4649-4_11.

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Rigina, Olga, et Alexander Baklanov. « Trends in Sulfur Emission-Induced Effects in Northern Europe ». Dans Biogeochemical Investigations at Watershed, Landscape, and Regional Scales, 331–42. Dordrecht : Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-017-0906-4_30.

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Marra, John, et Thomas S. Moore. « Monsoons, islands, and eddies : Their effects on phytoplankton in the Indian Ocean ». Dans Indian Ocean Biogeochemical Processes and Ecological Variability, 57–70. Washington, D. C. : American Geophysical Union, 2009. http://dx.doi.org/10.1029/2008gm000701.

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Haese, R. R. « Macrobenthic Activity and its Effects on Biogeochemical Reactions and Fluxes ». Dans Ocean Margin Systems, 219–34. Berlin, Heidelberg : Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-662-05127-6_14.

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De Angelis, Martine, et Michel Legrand. « Preliminary Investigations of Post Depositional Effects on HCl, HNO3, and Organic Acids in Polar Firn Layers ». Dans Ice Core Studies of Global Biogeochemical Cycles, 361–81. Berlin, Heidelberg : Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-642-51172-1_19.

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Actes de conférences sur le sujet "Biogeochemical effects"

Bushey, Joseph, Steven Brady, Steven Brady, Alejandra Aragon-Jose, Alejandra Aragon-Jose, Nakita Lancaster, Nakita Lancaster et al. « ROAD EFFECTS ON BIOGEOCHEMICAL CYCLING ». Dans 51st Annual Northeastern GSA Section Meeting. Geological Society of America, 2016. http://dx.doi.org/10.1130/abs/2016ne-272892.

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« Biogeochemical Carbon Cycle and its Effects ». Dans 2nd International Conference on Frontiers in Academic Research ICFAR 2023. All Sciences Academy, 2023. http://dx.doi.org/10.59287/as-proceedings.530.

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Ma, Yueliang, et Ruisong Xu. « Biogeochemical effects and remote sensing characteristics of gold deposit ». Dans Asia-Pacific Symposium on Remote Sensing of the Atmosphere, Environment, and Space, sous la direction de Robert O. Green et Qingxi Tong. SPIE, 1998. http://dx.doi.org/10.1117/12.317794.

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Gray, Katelyn, Deb Jaisi, Donald Sparks et Lisa Stout. « Effects of salinity on biogeochemical cycling of phosphorus in coastal soil ». Dans Goldschmidt2021. France : European Association of Geochemistry, 2021. http://dx.doi.org/10.7185/gold2021.4940.

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Mehr, Nicole K., Joseph M. Balnis, Brian W. Redder et Zsuzsanna Balogh-Brunstad. « THE BIOGEOCHEMICAL EFFECTS OF THE HEMLOCK WOOLLY ADELGID ON SOIL WATER CHEMISTRY ». Dans 51st Annual Northeastern GSA Section Meeting. Geological Society of America, 2016. http://dx.doi.org/10.1130/abs/2016ne-272378.

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Dontsova, Katerina, Ghiwa Makke, Malak Tfaily, Aditi Sengupta, Justin Garcia, Jon Chorover, Luis Cortes, Scott Saleska et Elizabeth Arnold. « Effects of biocrust formation and moss colonization on biogeochemical properties of basaltic tephra ». Dans Goldschmidt2023. France : European Association of Geochemistry, 2023. http://dx.doi.org/10.7185/gold2023.20292.

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Grbović, Filip, Gordana Gajić, Snežana Branković, Zoran Simić, Andrija Ćirić, Danijela Mišić et Marina Topuzović. « MOGUĆNOSTI I RIZICI PRIMENE INVAZIVNIH DRVENASTIH VRSTA U OBNOVI VEGETACIJE NA DEGRADIRANIM STANIŠTIMA ». Dans XXVII savetovanje o biotehnologiji. University of Kragujevac, Faculty of Agronomy, 2022. http://dx.doi.org/10.46793/sbt27.309g.

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The aim of this study is to use a comparative analysis of the ecology of invasive species Ailanthus altissima (Mill.) Swingle, Amoprha fruticosa L. and Robinia pseudoacacia L. to assess the possibilities and risks of their application in the soil and vegetation restoration in different anthropogenically modified habitats. The results of the comparative study indicate that selected tree species can have a positive effect on biogeochemical cycles and the initiation of pedogenesis. However, when using A. altissima and A. fruticosa in soil and vegetation restoration projects there is a potentially higher risk than benefit, due to the high allelopathic effects on other species in the habitat, compared to R. pseudoacacia.

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Mariam Paul, Nivya, et Variampally Sankar Harikumar. « Effects of biochar on soil microbial community composition using PLFA profiling- A review ». Dans 7th GoGreen Summit 2021. Technoarete, 2021. http://dx.doi.org/10.36647/978-93-92106-02-6.5.

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Biochar is a charcoal like substance produced from organic biomass after pyrolysis. Biochar act as a good soil conditioner by increasing microbial activities, soil nutrition and soil structure. Soil microorganisms are involved in litter decomposition and soil nutrient mineralization which is important in the sustainable development of plants and trees. The functioning of an ecosystem is controlled by biogeochemical cycles driven by microorganisms. The cell membrane of all microorganisms is composed of phospholipids that are easily metabolized after the cell death. Hence, phospholipid fatty acid (PLFA) analysis of microorganisms can be used for the characterization of living microbial communities. PLFA analysis is a lipid based, culture independent biochemical technique. Therefore, PLFAs can be used for the characterization of soil microbial community structure that are not able to cultivated by the conventional methods. This profiling act as a biological register of soil health, and as an indicator of soil response to different field management systems like biochar.

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Mohammed, Aboobacker Valliyil, Fazle Rakib, Ibrahim M. A. S. Al-Ansari, Yusuf Sinan Husrevoglu, Oguz Yigiterhan, Ibrahim A. M. J. Al-Maslamani et Vethamony Ponnumony. « Variability of Physical and Biogeochemical Parameters in the Exclusive Economic Zone of Qatar ». Dans Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2021. http://dx.doi.org/10.29117/quarfe.2021.0030.

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The oceanographic data collected along a transect in the Exclusive Economic Zone (EEZ) of Qatar during late summer (September 2014) and winter (January 2015) have been analyzed to investigate the spatial and temporal variability of hydrography and biogeochemistry. The study reveals that stratification is dominant in the deep-water regions during September, with a vertical variation of around 9 °C from surface to bottom. However, the water column remains in homogeneity during January due to strong wind mixing and surface cooling. The dissolved oxygen (DO) in the upper layer of the EEZ is on a reasonable range in both the seasons, while they gradually decrease with respect to depth in the mid and bottom layers during January. This leads to hypoxic conditions in summer. Chlorophyll-a (Chl-a ) is relatively high during summer in the offshore region, while that in the nearshore regions is very low. The variability in the physical and biogeochemical parameters has shown significant effects in primary productivity in the EEZ of Qatar.

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Penta, B., D. Ko, R. Gould, R. Arnone, R. Greene, J. Lehrter, J. Hagy et al. « Using coupled models to study the effects of river discharge on biogeochemical cycling and hypoxia in the northern Gulf Of Mexico ». Dans OCEANS 2009. IEEE, 2009. http://dx.doi.org/10.23919/oceans.2009.5422347.

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Rapports d'organisations sur le sujet "Biogeochemical effects"

Cooley, S. R., D. J. P. Moore, S. R. Alin, D. Butman, D. W. Clow, N. H. F. French, R. A. Feely et al. Chapter 17 : Biogeochemical Effects of Rising Atmospheric Carbon Dioxide. Second State of the Carbon Cycle Report. Sous la direction de N. Cavallaro, G. Shrestha, R. Birdsey, M. A. Mayes, R. Najjar, S. Reed, P. Romero-Lankao et Z. Zhu. U.S. Global Change Research Program, 2018. http://dx.doi.org/10.7930/soccr2.2018.ch17.

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Seifert, Miriam, Claudia Hinrichs, Judith Hauck et Christoph Völker. New / improved model parametrizations for responses in phytoplankton growth and calcification to changes in alkalinity implemented. OceanNets, mars 2023. http://dx.doi.org/10.3289/oceannets_d4.5.

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Global biogeochemical ocean models that are currently in place to investigate alkalinity enhancement at a global scale do usually not consider the effects of a changing carbonate system on phytoplankton. We introduce new and modified parameterizations of phytoplankton carbonate systems sensitivities into the biogeochemistry model REcoM. We then compare phytoplankton biomass and net primary production at different atmospheric CO2 concentrations to results from other deliverables (D5.3, 5.6, 5.7) based on experiments and models. The resilience of phytoplankton biomass towards low CO2 concentrations in our model compares well with the results of mesocosm experiments. Or model results differ in the phytoplankton responses compared to the results of a 1D biogeochemical model that employs similar parameterizations regarding the effects on calcifying phytoplankton and total net primary production, which we explain primarily with differences in the spatial scales and phytoplankton communities investigated.

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Sommer, Stefan. Potential effects of the exclusion of bottom fishing in the marine protected areas (MPAs) of the western Baltic Sea – third year observations Cruise No. AL570 22.03. – 11.04.2022, Kiel (Germany) – Kiel (Germany) MGF-OSTSEE-2022. GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany, 2022. http://dx.doi.org/10.3289/cr_al570.

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The expedition AL570 with the RV Alkor was carried out within the framework of the interdisciplinary DAM MGF-OSTSEE Project “Potential effects of closure for bottom fishing in the marine protected areas (MPAs) of the western Baltic Sea – baseline observations” funded by the Ministry of Education and Research (BMBF). Within MGF-OSTSEE a consortium of scientists from various institutions investigates how benthic ecosystems in Natura 2000 areas within the German exclusive economic zone develop after the exclusion of bottom trawling. Major goals of the project are i. the initial assessment of the environmental state and its variability in- and outside the three Natura 2000 areas Fehmarnbelt, Oder- and Rönnebank under the ongoing pressure of bottom trawling and ii. the general assessment of the effect of bottom trawling on benthic communities and benthic biogeochemical functioning as well as their development after fishery exclusion. The cruise AL570 concludes a series of three previous expeditions EMB238 (2020) and EMB267/268 (2021) and aimed to survey all components of the benthic food web including prokaryotes, protozoans, meiofauna and macrofauna, as well as sediment properties and biogeochemical processes in selected working areas in- and outside of the MPA. The working program comprised 156 station activities of various gears for biological and biogeochemical sampling of sediments. Solute exchange between the sediment and the water column was investigated using Landers and a novel underwater vehicle the Deep-Sea Rover (DSR) Panta Rhei. Investigations in the water column, seafloor observation and deployments of a dredge supplemented the station work. Due to stormy weather in situ solute fluxe measurements were not performed at the Rönnebank. (Alkor-Berichte ; AL570)

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Taucher, Jan, et Markus Schartau. Report on parameterizing seasonal response patterns in primary- and net community production to ocean alkalinization. OceanNETs, novembre 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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Taucher, Jan, et Markus Schartau. Report on parameterizing seasonal response patterns in primary- and net community production to ocean alkalinization. OceanNETs, 2021. http://dx.doi.org/10.3289/oceannets_d5.3.

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Chefetz, Benny, Baoshan Xing, Leor Eshed-Williams, Tamara Polubesova et Jason Unrine. DOM affected behavior of manufactured nanoparticles in soil-plant system. United States Department of Agriculture, janvier 2016. http://dx.doi.org/10.32747/2016.7604286.bard.

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The overall goal of this project was to elucidate the role of dissolved organic matter (DOM) in soil retention, bioavailability and plant uptake of silver and cerium oxide NPs. The environmental risks of manufactured nanoparticles (NPs) are attracting increasing attention from both industrial and scientific communities. These NPs have shown to be taken-up, translocated and bio- accumulated in plant edible parts. However, very little is known about the behavior of NPs in soil-plant system as affected by dissolved organic matter (DOM). Thus DOM effect on NPs behavior is critical to assessing the environmental fate and risks related to NP exposure. Carbon-based nanomaterials embedded with metal NPs demonstrate a great potential to serve as catalyst and disinfectors. Hence, synthesis of novel carbon-based nanocomposites and testing them in the environmentally relevant conditions (particularly in the DOM presence) is important for their implementation in water purification. Sorption of DOM on Ag-Ag₂S NPs, CeO₂ NPs and synthesized Ag-Fe₃O₄-carbon nanotubebifunctional composite has been studied. High DOM concentration (50mg/L) decreased the adsorptive and catalytic efficiencies of all synthesized NPs. Recyclable Ag-Fe₃O₄-carbon nanotube composite exhibited excellent catalytic and anti-bacterial action, providing complete reduction of common pollutants and inactivating gram-negative and gram-positive bacteria at environmentally relevant DOM concentrations (5-10 mg/L). Our composite material may be suitable for water purification ranging from natural to the industrial waste effluents. We also examined the role of maize (Zeamays L.)-derived root exudates (a form of DOM) and their components on the aggregation and dissolution of CuONPs in the rhizosphere. Root exudates (RE) significantly inhibited the aggregation of CuONPs regardless of ionic strength and electrolyte type. With RE, the critical coagulation concentration of CuONPs in NaCl shifted from 30 to 125 mM and the value in CaCl₂ shifted from 4 to 20 mM. This inhibition was correlated with molecular weight (MW) of RE fractions. Higher MW fraction (> 10 kDa) reduced the aggregation most. RE also significantly promoted the dissolution of CuONPs and lower MW fraction (< 3 kDa) RE mainly contributed to this process. Also, Cu accumulation in plant root tissues was significantly enhanced by RE. This study provides useful insights into the interactions between RE and CuONPs, which is of significance for the safe use of CuONPs-based antimicrobial products in agricultural production. Wheat root exudates (RE) had high reducing ability to convert Ag+ to nAg under light exposure. Photo-induced reduction of Ag+ to nAg in pristine RE was mainly attributed to the 0-3 kDa fraction. Quantification of the silver species change over time suggested that Cl⁻ played an important role in photoconversion of Ag+ to nAg through the formation and redox cycling of photoreactiveAgCl. Potential electron donors for the photoreduction of Ag+ were identified to be reducing sugars and organic acids of low MW. Meanwhile, the stabilization of the formed particles was controlled by both low (0-3 kDa) and high (>3 kDa) MW molecules. This work provides new information for the formation mechanism of metal nanoparticles mediated by RE, which may further our understanding of the biogeochemical cycling and toxicity of heavy metal ions in agricultural and environmental systems. Copper sulfide nanoparticles (CuSNPs) at 1:1 and 1:4 ratios of Cu and S were synthesized, and their respective antifungal efficacy was evaluated against the pathogenic activity of Gibberellafujikuroi(Bakanae disease) in rice (Oryza sativa). In a 2-d in vitro study, CuS decreased G. fujikuroiColony- Forming Units (CFU) compared to controls. In a greenhouse study, treating with CuSNPs at 50 mg/L at the seed stage significantly decreased disease incidence on rice while the commercial Cu-based pesticide Kocide 3000 had no impact on disease. Foliar-applied CuONPs and CuS (1:1) NPs decreased disease incidence by 30.0 and 32.5%, respectively, which outperformed CuS (1:4) NPs (15%) and Kocide 3000 (12.5%). CuS (1:4) NPs also modulated the shoot salicylic acid (SA) and Jasmonic acid (JA) production to enhance the plant defense mechanisms against G. fujikuroiinfection. These results are useful for improving the delivery efficiency of agrichemicals via nano-enabled strategies while minimizing their environmental impact, and advance our understanding of the defense mechanisms triggered by the NPs presence in plants.

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Microbes in Models : Integrating Microbes into Earth System Models for Understanding Climate Change. American Society for Microbiology, juin 2023. http://dx.doi.org/10.1128/aamcol.jun.2023.

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Climate change is altering the planet and threatens humanity. Earth system models simulate the planet's physical, chemical, and biological processes to help scientists understand current environmental changes and make projections for Earth's future, which can inform society's responses to combat and mitigate climate change's negative effects. Climate change will fundamentally change life on Earth, including microorganisms. Microbes will also influence climate change by driving biogeochemical cycles through the consumption and production of greenhouse gasses. Thus, explicitly including microbial processes into Earth system models can improve model projections. However, fully understanding the feedbacks between climate change and microbes, and then including those processes into Earth systems models, is a major challenge. This report is based on the deliberations of experts who participated in a virtual colloquium on 6 and 8 December, 2022, organized by the American Academy of Microbiology, which is the honorific leadership group and think tank within the American Society for Microbiology. At the colloquium, these experts from the climate and microbial sciences attempted to clearly articulate current knowledge gaps of the two fields. As a result, the participants compiled a list of top ten challenges to better incorporate microbial processes into Earth system models. Solving these challenges requires new thinking and approaches. Transdisciplinary efforts have the potential to propel science—and society—towards combating climate change.

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