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Articles de revues sur le sujet « Biogeochemical effects »

Auteur : Grafiati
Publié le 25 janvier 2025

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1

Chi, Zhi-Lai, et Guang-Hui Yu. « Nanozyme-mediated elemental biogeochemical cycling and environmental effects ». Science China Earth Sciences 64, no 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, no 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, no 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, no 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, no 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, no 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, no 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, no 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, no 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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Bush, T., I. B. Butler, A. Free et R. J. Allen. « Redox regime shifts in microbially-mediated biogeochemical cycles ». Biogeosciences Discussions 12, no 4 (17 février 2015) : 3283–314. http://dx.doi.org/10.5194/bgd-12-3283-2015.

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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 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 sulfur and nitrogen cycles in the present-day natural environment, and 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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Persson, K., J. Jarsjö et G. Destouni. « Diffuse hydrological mass transport through catchments : scenario analysis of coupled physical and biogeochemical uncertainty effects ». Hydrology and Earth System Sciences 15, no 10 (20 octobre 2011) : 3195–206. http://dx.doi.org/10.5194/hess-15-3195-2011.

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Abstract. This paper quantifies and maps the effects of coupled physical and biogeochemical variability on diffuse hydrological mass transport through and from catchments. It further develops a scenario analysis approach and investigates its applicability for handling uncertainties about both physical and biogeochemical variability and their different possible cross-correlation. The approach enables identification of conservative assumptions, uncertainty ranges, as well as pollutant/nutrient release locations and situations for which further investigations are most needed in order to reduce the most important uncertainty effects. The present scenario results provide different statistical and geographic distributions of advective travel times for diffuse hydrological mass transport. The geographic mapping can be used to identify potential hotspot areas with large mass loading to downstream surface and coastal waters, as well as their opposite, potential lowest-impact areas within the catchment. Results for alternative travel time distributions show that neglect or underestimation of the physical advection variability, and in particular of those transport pathways with much shorter than average advective solute travel times, can lead to substantial underestimation of pollutant and nutrient loads to downstream surface and coastal waters. This is particularly true for relatively high catchment-characteristic product of average attenuation rate and average advective travel time, for which mass delivery would be near zero under assumed transport homogeneity but can be orders of magnitude higher for variable transport conditions. A scenario of high advection variability, with a significant fraction of relatively short travel times, combined with a relevant average biogeochemical mass attenuation rate, emerges consistently from the present results as a generally reasonable, conservative assumption for estimating maximum diffuse mass loading, when the prevailing physical and biogeochemical variability and cross-correlation are uncertain.
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PERSSON, ANDERS, et JONAS M. SVENSSON. « Effects of benthivorous fish on biogeochemical processes in lake sediments ». Freshwater Biology 51, no 7 (juillet 2006) : 1298–309. http://dx.doi.org/10.1111/j.1365-2427.2006.01569.x.

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14

Melott, Adrian L., Brian C. Thomas, Daniel P. Hogan, Larissa M. Ejzak et Charles H. Jackman. « Climatic and biogeochemical effects of a galactic gamma ray burst ». Geophysical Research Letters 32, no 14 (21 juillet 2005) : n/a. http://dx.doi.org/10.1029/2005gl023073.

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15

José, Yonss Saranga, Heiner Dietze et Andreas Oschlies. « Linking diverse nutrient patterns to different water masses within anticyclonic eddies in the upwelling system off Peru ». Biogeosciences 14, no 6 (20 mars 2017) : 1349–64. http://dx.doi.org/10.5194/bg-14-1349-2017.

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Abstract. Ocean eddies can both trigger mixing (during their formation and decay) and effectively shield water encompassed from being exchanged with ambient water (throughout their lifetimes). These antagonistic effects of eddies complicate the interpretation of synoptic snapshots typically obtained by ship-based oceanographic measurement campaigns. Here we use a coupled physical–biogeochemical model to explore biogeochemical dynamics within anticyclonic eddies in the eastern tropical South Pacific Ocean. The goal is to understand the diverse biogeochemical patterns that have been observed at the subsurface layers of the anticyclonic eddies in this region. Our model results suggest that the diverse subsurface nutrient patterns within eddies are associated with the presence of water masses of different origins at different depths.
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Rodie, Andrew, Jan J. P. Gerits et Jose M. Azcue. « Biogeochemical pathways of arsenic in lakes ». Environmental Reviews 3, no 3-4 (1 juillet 1995) : 304–17. http://dx.doi.org/10.1139/a95-016.

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Owing to various human activities, arsenic (As) concentrations have increased in lakes and other aquatic ecosystems around the world. This increase of As concentrations has become a concern because of the known toxic, carcinogenic, mutagenic, and teratogenic effects of As on ecosystem organisms and humans. Understanding the biogeochemistry of As in the aquatic environment is therefore a topic of fundamental interest. This study presents a review of the major biogeochemical processes controlling the concentration of solid and dissolved As in freshwater lakes. These processes are dynamic and vary both temporally and spatially because of a complex relationship between microbial activity and various geochemical processes. Particularly the oxidation of As sulphides and the reduction of Fe and Mn oxyhydroxides at the sediment–water interface play an important role in the mobilization of As. These and other interactions among the various biogeochemical processes are synthesized in a conceptual model of As mobility in lakes.Key words: arsenic cycling, biogeochemistry, freshwater lakes.
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Campbell, John L., Lindsey E. Rustad, Elizabeth W. Boyer, Sheila F. Christopher, Charles T. Driscoll, Ivan J. Fernandez, Peter M. Groffman et al. « Consequences of climate change for biogeochemical cycling in forests of northeastern North AmericaThis article is one of a selection of papers from NE Forests 2100 : A Synthesis of Climate Change Impacts on Forests of the Northeastern US and Eastern Canada. » Canadian Journal of Forest Research 39, no 2 (février 2009) : 264–84. http://dx.doi.org/10.1139/x08-104.

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A critical component of assessing the impacts of climate change on forest ecosystems involves understanding associated changes in the biogeochemical cycling of elements. Evidence from research on northeastern North American forests shows that direct effects of climate change will evoke changes in biogeochemical cycling by altering plant physiology, forest productivity, and soil physical, chemical, and biological processes. Indirect effects, largely mediated by changes in species composition, length of growing season, and hydrology, will also be important. The case study presented here uses the quantitative biogeochemical model PnET-BGC to test assumptions about the direct and indirect effects of climate change on a northern hardwood forest ecosystem. Modeling results indicate an overall increase in net primary production due to a longer growing season, an increase in NO3– leaching due to large increases in net mineralization and nitrification, and slight declines in mineral weathering due to a reduction in soil moisture. Future research should focus on uncertainties, including the effects of (1) multiple simultaneous interactions of stressors (e.g., climate change, ozone, acidic deposition); (2) long-term atmospheric CO2 enrichment on vegetation; (3) changes in forest species composition; (4) extreme climatic events and other disturbances (e.g., ice storms, fire, invasive species); and (5) feedback mechanisms that increase or decrease change.
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Tian, Qian, Dong Liu, Peng Yuan, Mengyuan Li, Weifeng Yang, Jieyu Zhou, Huihuang Wei, Junming Zhou et Haozhe Guo. « Occurrence of structural aluminium (Al) in marine diatom biological silica : visible evidence from microscopic analysis ». Ocean Science 18, no 2 (17 mars 2022) : 321–29. http://dx.doi.org/10.5194/os-18-321-2022.

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Abstract. The global marine biogeochemical cycle of aluminium (Al) is believed to be driven by marine diatoms, due to the uptake of dissolved Al (DAl) by living diatoms from surface seawater. The occurrence of Al in diatom biogenic silica (BSi) can inhibit the dissolution of BSi, thus benefiting the effects of the ballast role of diatoms in the biological pump and forming a coupled Si–Al biogeochemical cycle. However, the occurrence characteristic of Al in marine diatoms is still unclear. In particular, whether or not Al is incorporated into the structure of BSi of living diatoms is unrevealed, resulting in difficulties in understanding the biogeochemical behaviours of Al. In this study, Thalassiosira weissflogii, a widely distributed marine diatom in marginal seas, was selected as the model to evaluate the occurrence of structural Al in BSi based on culturing experiments with the addition of DAl. The structural Al in BSi was detected by combining focused ion beam (FIB) scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDS) mapping analysis. Visible, direct evidence of structural Al in living BSi was obtained, and the distribution and content of this Al were revealed by the EDS-mapping analysis. The effects of structural Al on BSi dissolution–inhibition are discussed based on the content of this Al. The fundamental results indicate the significant contribution of marine diatoms to the biogeochemical migration of marine Al.
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Wang, Pingping, Faqin Dong, Xuhui Wang, Mingxue Liu, Xiaoqin Nie, Lei Zhou, Tingting Huo, Wei Zhang et Hongfu Wei. « Effects of riboflavin and AQS as electron shuttles on U(vi) reduction and precipitation byShewanella putrefaciens ». RSC Advances 8, no 54 (2018) : 30692–700. http://dx.doi.org/10.1039/c8ra05715j.

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Understanding the mechanisms for electron shuttles (ESs) in microbial extracellular electron transfer (EET) is important in biogeochemical cycles, bioremediation applications, as well as bioenergy strategies.
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Persson, K., J. Jarsjö et G. Destouni. « Diffuse hydrological mass transport through catchments : scenario analysis of physical and biogeochemical uncertainty effects ». Hydrology and Earth System Sciences Discussions 8, no 3 (12 mai 2011) : 4721–52. http://dx.doi.org/10.5194/hessd-8-4721-2011.

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Abstract. This paper develops and investigates the applicability of a scenario analysis approach to quantify and map the effects of physical and biogeochemical variability, cross-correlation and uncertainty on expected hydrological mass loading from diffuse sources. The approach enables identification of conservative assumptions, uncertainty ranges, as well as pollutant/nutrient release locations and situations for which further investigations are most needed in order to reduce the most important uncertainty effects. The present scenario results provide different statistical and geographic distributions of advective travel times for diffuse hydrological mass transport, and show that neglect or underestimation of the physical advection variability implies substantial risk to underestimate pollutant and nutrient loads to downstream surface and coastal waters. This is particularly true for relatively high catchment-characteristic product between average attenuation rate and average advective travel time, for which mass delivery would be near zero under assumed transport homogeneity but can be orders of magnitude higher for variable transport conditions. A scenario of high advection variability, combined with a relevant average biogeochemical mass attenuation rate, emerges consistently from the example catchment results as a generally reasonable, conservative assumption for estimating maximum diffuse mass loading when the prevailing physical and biogeochemical variability and cross-correlation are uncertain. The geographic mapping of advective travel times for this high-variability scenario identifies also directly the potential hotspot areas with large mass loading to downstream surface and coastal waters, as well as their opposite, the potential lowest-impact areas within the catchment.
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Ptitsyn, A. B., et E. B. Matyugina. « Water as a thermodynamic parameter of biosphere evolution ». IOP Conference Series : Earth and Environmental Science 962, no 1 (1 janvier 2022) : 012031. http://dx.doi.org/10.1088/1755-1315/962/1/012031.

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Abstract Water has a profound influence on the evolution of the biosphere and can be regarded as a thermodynamic parameter. The priorities and objectives in this research include determining the hydrological features of rivers and lakes in the region as indicators of the thermodynamic activity of water in the evolutionary processes; hydrology and ecology of the cryptobiosphere; the effects of water on the evolutionary adaptations and strategies in living organisms in biogeochemical systems of different origins; and the hydrology of possible alternative stable states of biogeochemical systems.
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Zhang, Menghui, Tianyou Zhang, Meishun Yu, Yu-Lei Chen et Min Jin. « The Life Cycle Transitions of Temperate Phages : Regulating Factors and Potential Ecological Implications ». Viruses 14, no 9 (28 août 2022) : 1904. http://dx.doi.org/10.3390/v14091904.

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Phages are viruses that infect bacteria. They affect various microbe-mediated processes that drive biogeochemical cycling on a global scale. Their influence depends on whether the infection is lysogenic or lytic. Temperate phages have the potential to execute both infection types and thus frequently switch their infection modes in nature, potentially causing substantial impacts on the host-phage community and relevant biogeochemical cycling. Understanding the regulating factors and outcomes of temperate phage life cycle transition is thus fundamental for evaluating their ecological impacts. This review thus systematically summarizes the effects of various factors affecting temperate phage life cycle decisions in both culturable phage-host systems and natural environments. The review further elucidates the ecological implications of the life cycle transition of temperate phages with an emphasis on phage/host fitness, host-phage dynamics, microbe diversity and evolution, and biogeochemical cycles.
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Blake, R. E. « Biogeochemical cycling of phosphorus : Insights from oxygen isotope effects of phosphoenzymes ». American Journal of Science 305, no 6-8 (1 juin 2005) : 596–620. http://dx.doi.org/10.2475/ajs.305.6-8.596.

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García-Robledo, E., A. Corzo, JG de Lomas et SA van Bergeijk. « Biogeochemical effects of macroalgal decomposition on intertidal microbenthos : a microcosm experiment ». Marine Ecology Progress Series 356 (18 mars 2008) : 139–51. http://dx.doi.org/10.3354/meps07287.

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QUANTIN, C., O. GRUNBERGER, N. SUVANNANG et E. BOURDON. « Land Management Effects on Biogeochemical Functioning of Salt-Affected Paddy Soils ». Pedosphere 18, no 2 (avril 2008) : 183–94. http://dx.doi.org/10.1016/s1002-0160(08)60006-5.

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Walbridge, Mark R., et B. Graeme Lockaby. « Effects of forest management on biogeochemical functions in southern forested wetlands ». Wetlands 14, no 1 (mars 1994) : 10–17. http://dx.doi.org/10.1007/bf03160617.

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Gao, Jie, Yu Wang, Anna Hovsepyan et Jean-Claude J. Bonzongo. « Effects of engineered nanomaterials on microbial catalyzed biogeochemical processes in sediments ». Journal of Hazardous Materials 186, no 1 (février 2011) : 940–45. http://dx.doi.org/10.1016/j.jhazmat.2010.11.084.

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Chen, Hung-Yu, et Ting-Wen Liu. « Composition and Biogeochemical Effects of Carbohydrates in Aerosols in Coastal Environment ». Journal of Marine Science and Engineering 12, no 10 (14 octobre 2024) : 1834. http://dx.doi.org/10.3390/jmse12101834.

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We adopted a simple and rapid measurement method to analyze the concentrations of monosaccharides (MCHO) and polysaccharides (PCHO) in carbohydrates, a subset of organic carbon found in size-fractionated atmospheric particles. Seasonal and source-related factors influenced carbohydrate concentrations, with total water-soluble carbohydrates (TCHO) accounting for approximately 23% of the water-soluble organic carbon (WSOC) in spring when biological activity was high. We observed that the mode of aerosol transport significantly influenced the particle size distribution of carbohydrates, with MCHO exhibiting relatively high concentrations in fine particles (<1 μm) and PCHO showing higher concentrations in coarse particles (>1 μm). Moreover, our results revealed that MCHO and PCHO contributed 51% and 49%, respectively, to the TCHO concentration. This contribution varied by approximately ±19% depending on the season, suggesting the importance of both MCHO and PCHO. Additionally, through the combined use of principal component analysis (PCA) and positive matrix factorization (PMF), we determined that biomass burning accounts for 30% of the aerosol. Notably, biomass burning accounts for approximately 52% of the WSOC flux, with MCHO accounting for approximately 78% of the carbon from this source, indicating the substantial influence of biomass burning on aerosol composition. The average concentration of TCHO/WSOC in the atmosphere was approximately 18%, similar to the marine environment, reflecting the relationship between the biogeochemical cycles of the two environments. Finally, the fluxes of MCHO and PCHO were 1.10 and 5.28 mg C m−2 yr−1, respectively. We also found that the contribution of atmospheric deposition to marine primary productivity in winter was 15 times greater than that in summer, indicating that atmospheric deposition had a significant impact on marine ecosystems during nutrient-poor seasons. Additionally, we discovered that WSOC accounts for approximately 62% of the dissolved organic carbon (DOC) in the Min River, suggesting that atmospheric deposition could be a major source of organic carbon in the region.
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Erickson, Paul R., et Vivian S. Lin. « Research highlights : elucidation of biogeochemical factors influencing methylmercury production ». Environmental Science : Processes & ; Impacts 17, no 10 (2015) : 1708–11. http://dx.doi.org/10.1039/c5em90037a.

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This Highlight features recent articles that examine in detail the effects of nutrient availability on the methylation–demethylation activity of microorganisms living in sediment with mercury contamination.
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de Almeida, Marcelo P., Christine C. Gaylarde, José Antônio Baptista Neto, Jéssica de F. Delgado, Leonardo da S. Lima, Charles V. Neves, Lara L. de O. Pompermayer, Khauê Vieira et Estefan M. da Fonseca. « The prevalence of microplastics on the earth and resulting increased imbalances in biogeochemical cycling ». Water Emerging Contaminants & ; Nanoplastics 2, no 2 (2023) : 7. http://dx.doi.org/10.20517/wecn.2022.20.

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The biogeochemical cycles are responsible for the constant transfer and transformation of matter and energy between the biosphere and the other active reservoirs of the planet. During the progress of a biogeochemical cycle, a series of molecular species (ecological “nutrients”) are constantly transferred and chemically altered. Plastic, a new material, has now begun to participate in the biogeochemical cycles. More than just participating, microplastics are interfering with the normal flow of these processes insofar as they can block the transfer of some elements and serve as a shortcut for others. These new materials can increase the bioavailability of pollutants and thus interfere with physiological activities. The results of this interference have not yet been fully evaluated, but in view of the universal presence of these particles in the most varied ecosystems of the planet, urgent measures must be taken to mitigate the negative effects of this invasion. The present review seeks to establish a global view of the distribution of microplastics around the planet and their impact on the main biogeochemical cycles, thus emphasizing the need for the development of adequate management and remediation strategies in the coming years.
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Терещенко, Н. Н. « Application of the G. G. Polikarpov conceptual model of chronic action zonality of ionizing irradiation doze rates to biosphere objects in applied hydrobiology ». Marine Biological Journal 5, no 3 (30 septembre 2020) : 85–100. http://dx.doi.org/10.21072/mbj.2020.05.3.08.

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Evolution of the approach to assessing ionizing radiation effects on living organisms is briefly discussed in this paper. Using the example of Black Sea hydrobionts, possibility of applying the G. G. Polikarpov conceptual radiochemoecological model of chronic action zonality of ionizing irradiation dose rates in nature to assess ecological exposure of technogenic radioisotopes ionizing radiation on aquatic biota was shown. In applied hydrobiology, this model can serve as the basis for a complex approach in assessing aquatic biota ecological state and its prediction for a wide range of 239,240Pu activity concentration in seawater. The necessity of combined use of biogeochemical and equidosimetric indicators of radionuclide behavior in a water area is emphasized. In particular, for predictive dosimetric assessments, it is important to take into account quantitative characteristics of accumulative ability of Black Sea hydrobionts and a type of radioelement biogeochemical behavior, reflecting peculiarities of plutonium biogeochemical migration in a marine ecosystem.
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Mangan, Stephanie, Andrew M. Lohrer, Simon F. Thrush, Joanne I. Ellis et Conrad A. Pilditch. « The Effects of Long-Term Nitrogen Enrichment on Estuarine Benthic-Pelagic Coupling ». Journal of Marine Science and Engineering 10, no 12 (9 décembre 2022) : 1955. http://dx.doi.org/10.3390/jmse10121955.

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Biogeochemical cycling in the marine coastal zone regulates the availability of nitrogen and carbon within soft sediment habitats. However, these pathways are being fundamentally altered by anthropogenic increases in nutrient delivery. Few studies have incorporated long-term enrichment and ecological complexity (in situ experiments), restricting our ability to manage effectively and prevent ecological shifts. This study investigates the influence of sediment nutrient availability (at 3 levels, across 2 seasons) on biogeochemical cycling over a 20-month period in 4 estuaries. Overall, net denitrification rates were highly variable, ranging between 4 and 208 µmol N m−2 h−1. However, no increases were observed with increasing enrichment highlighting the limited capacity for nitrogen removal in response to large increases in bioavailable nitrogen. Additionally, macrofaunal communities and sediment trophic status were shown to have important influences on nitrogen processing. Overall, alterations to ecosystem relationships and the appearance of non-linear responses to increasing nutrient enrichment reveal the vulnerability of estuaries to increasing stressor loads owing to the increased likelihood of reaching a tipping point.
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Peña, M. A., S. Katsev, T. Oguz et D. Gilbert. « Modeling dissolved oxygen dynamics and hypoxia ». Biogeosciences 7, no 3 (9 mars 2010) : 933–57. http://dx.doi.org/10.5194/bg-7-933-2010.

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Abstract. Hypoxia conditions are increasing throughout the world, influencing biogeochemical cycles of elements and marine life. Hypoxia results from complex interactions between physical and biogeochemical processes, which can not be understood by observations alone. Models are invaluable tools at studying system dynamics, generalizing discrete observations and predicting future states. They are also useful as management tools for evaluating site-specific responses to management scenarios. Here we review oxygen dynamics models that have significantly contributed to a better understanding of the effects of natural processes and human perturbations on the development of hypoxia, factors controlling the extent and temporal variability of coastal hypoxia, and the effects of oxygen depletion on biogeochemical cycles. Because hypoxia occurs in a variety of environments and can be persistent, periodic or episodic, models differ significantly in their complexity and temporal and spatial resolution. We discuss the progress in developing hypoxia models for benthic and pelagic systems that range from simple box models to three dimensional circulation models. Applications of these models in five major hypoxia regions are presented. In the last decades, substantial progress has been made towards the parameterization of biogeochemical processes in both hypoxic water columns and sediments. In coastal regions, semi-empirical models have been used more frequently than mechanistic models to study nutrient enrichment and hypoxia relationships. Recent advances in three-dimensional coupled physical-ecological-biogeochemical models have allowed a better representation of physical-biological interactions in these systems. We discuss the remaining gaps in process descriptions and suggest directions for improvement. Better process representations in models will help us answer several important questions, such as those about the causes of the observed worldwide increase in hypoxic conditions, and future changes in the intensity and spread of coastal hypoxia. At the same time, quantitative model intercomparison studies suggest that the predictive ability of our models may be adversely affected by their increasing complexity, unless the models are properly constrained by observations.
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Xenopoulos, Marguerite A., Rebecca T. Barnes, Kyle S. Boodoo, David Butman, Núria Catalán, Sarah C. D’Amario, Christina Fasching et al. « How humans alter dissolved organic matter composition in freshwater : relevance for the Earth’s biogeochemistry ». Biogeochemistry 154, no 2 (25 janvier 2021) : 323–48. http://dx.doi.org/10.1007/s10533-021-00753-3.

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AbstractDissolved organic matter (DOM) is recognized for its importance in freshwater ecosystems, but historical reliance on DOM quantity rather than indicators of DOM composition has led to an incomplete understanding of DOM and an underestimation of its role and importance in biogeochemical processes. A single sample of DOM can be composed of tens of thousands of distinct molecules. Each of these unique DOM molecules has their own chemical properties and reactivity or role in the environment. Human activities can modify DOM composition and recent research has uncovered distinct DOM pools laced with human markers and footprints. Here we review how land use change, climate change, nutrient pollution, browning, wildfires, and dams can change DOM composition which in turn will affect internal processing of freshwater DOM. We then describe how human-modified DOM can affect biogeochemical processes. Drought, wildfires, cultivated land use, eutrophication, climate change driven permafrost thaw, and other human stressors can shift the composition of DOM in freshwater ecosystems increasing the relative contribution of microbial-like and aliphatic components. In contrast, increases in precipitation may shift DOM towards more relatively humic-rich, allochthonous forms of DOM. These shifts in DOM pools will likely have highly contrasting effects on carbon outgassing and burial, nutrient cycles, ecosystem metabolism, metal toxicity, and the treatments needed to produce clean drinking water. A deeper understanding of the links between the chemical properties of DOM and biogeochemical dynamics can help to address important future environmental issues, such as the transfer of organic contaminants through food webs, alterations to nitrogen cycling, impacts on drinking water quality, and biogeochemical effects of global climate change.
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Sein, Dmitry V., Anton Y. Dvornikov, Stanislav D. Martyanov, William Cabos, Vladimir A. Ryabchenko, Matthias Gröger, Daniela Jacob, Alok Kumar Mishra et Pankaj Kumar. « Indian Ocean marine biogeochemical variability and its feedback on simulated South Asia climate ». Earth System Dynamics 13, no 2 (13 avril 2022) : 809–31. http://dx.doi.org/10.5194/esd-13-809-2022.

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Abstract. We investigate the effect of variable marine biogeochemical light absorption on Indian Ocean sea surface temperature (SST) and how this affects the South Asian climate. In twin experiments with a regional Earth system model, we found that the average SST is lower over most of the domain when variable marine biogeochemical light absorption is taken into account, compared to the reference experiment with a constant light attenuation coefficient equal to 0.06 m−1. The most significant deviations (more than 1 ∘C) in SST are observed in the monsoon season. A considerable cooling of subsurface layers occurs, and the thermocline shifts upward in the experiment with the activated biogeochemical impact. Also, the phytoplankton primary production becomes higher, especially during periods of winter and summer phytoplankton blooms. The effect of altered SST variability on climate was investigated by coupling the ocean models to a regional atmosphere model. We find the largest effects on the amount of precipitation, particularly during the monsoon season. In the Arabian Sea, the reduction of the transport of humidity across the Equator leads to a reduction of the large-scale precipitation in the eastern part of the basin, reinforcing the reduction of the convective precipitation. In the Bay of Bengal, it increases the large-scale precipitation, countering convective precipitation decline. Thus, the key impacts of including the full biogeochemical coupling with corresponding light attenuation, which in turn depends on variable chlorophyll a concentration, include the enhanced phytoplankton primary production, a shallower thermocline, and decreased SST and water temperature in subsurface layers, with cascading effects upon the model ocean physics which further translates into altered atmosphere dynamics.
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Fuchslueger, Lucia, Emily Francesca Solly, Alberto Canarini et Albert Carles Brangarí. « Overview : Global change effects on terrestrial biogeochemistry at the plant–soil interface ». Biogeosciences 21, no 17 (6 septembre 2024) : 3959–64. http://dx.doi.org/10.5194/bg-21-3959-2024.

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Abstract. “Global change” significantly alters organic matter and element cycling, but many of the underlying processes and consequences remain poorly understood. The interface of plants and soil plays a central role, coupling the atmosphere, hydrosphere, biosphere and lithosphere and integrating biological and geochemical processes. The contributions to this special issue address questions on both biotic and abiotic interactions underlying responses of terrestrial biogeochemical cycling to a range of global changes, including increases in atmospheric CO2 concentrations, warming, drought and altered water regimes. In this overview, we synthesize key findings of the contributing empirical, conceptual and modelling-based studies covering responses of plants to elevated CO2; the role of soil organisms in modulating responses to warming; impacts of global change on soil organic carbon, nitrogen, and mineral nutrient availability; and the influence of altered water-table depth caused by global change on greenhouse gas emissions. The showcased studies were conducted in regions from the Arctic to the tropics and highlight the manifold impacts of global change on various ecosystem components controlling biogeochemical processes occurring at the plant–soil interface. This multi-ecosystem interdisciplinary understanding is crucial for deciphering feedbacks of terrestrial ecosystems to the climate system.
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Gan, Dayong, Jiguang Feng, Mengguang Han, Hui Zeng et Biao Zhu. « Rhizosphere effects of woody plants on soil biogeochemical processes : A meta-analysis ». Soil Biology and Biochemistry 160 (septembre 2021) : 108310. http://dx.doi.org/10.1016/j.soilbio.2021.108310.

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Ma, Yuandan, Kai Yue, Petr Heděnec, Cuihuan Li, Yan Li et Qiqian Wu. « Global patterns of rhizosphere effects on soil carbon and nitrogen biogeochemical processes ». CATENA 220 (janvier 2023) : 106661. http://dx.doi.org/10.1016/j.catena.2022.106661.

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Fiskal, Annika, Aixala Gaillard, Sebastien Giroud, Dejan Malcic, Prachi Joshi, Michael Sander, Carsten J. Schubert et Mark Alexander Lever. « Effects of Macrofaunal Recolonization on Biogeochemical Processes and Microbiota—A Mesocosm Study ». Water 13, no 11 (6 juin 2021) : 1599. http://dx.doi.org/10.3390/w13111599.

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Macroinvertebrates are widespread in lake sediments and alter sedimentary properties through their activity (bioturbation). Understanding the interactions between bioturbation and sediment properties is important given that lakes are important sinks and sources of carbon and nutrients. We studied the biogeochemical impact of macrofauna on surface sediments in 3-month-long mesocosm experiments conducted using sediment cores from a hypoxic, macrofauna-free lake basin. Experimental units consisted of hypoxic controls, oxic treatments, and oxic treatments that were experimentally colonized with chironomid larvae or tubificid worms. Overall, the presence of O2 in bottom water had the strongest geochemical effect and led to oxidation of sediments down to 2 cm depth. Relative to macrofauna-free oxic treatments, chironomid larvae increased sediment pore water concentrations of nitrate and sulfate and lowered porewater concentrations of reduced metals (Fe2+, Mn2+), presumably by burrow ventilation, whereas tubificid worms increased the redox potential, possibly through sediment reworking. Microbial communities were very similar across oxic treatments; however, the fractions of α-, β-, and γ-Proteobacteria and Sphingobacteriia increased, whereas those of Actinobacteria, Planctomycetes, and Omnitrophica decreased compared to hypoxic controls. Sediment microbial communities were, moreover, distinct from those of macrofaunal tubes or feces. We suggest that, under the conditions studied, bottom water oxygenation has a stronger biogeochemical impact on lacustrine surface sediments than macrofaunal bioturbation.
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Mosley, Luke M., Tan Dang, Michael J. McLaughlin et Rob W. Fitzpatrick. « Extreme biogeochemical effects following simulation of recurrent drought in acid sulfate soils ». Applied Geochemistry 136 (janvier 2022) : 105146. http://dx.doi.org/10.1016/j.apgeochem.2021.105146.

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Zou, Xiaoming, Dan Binkley et Bruce A. Caldwell. « Effects of Dinitrogen-Fixing Trees on Phosphorus Biogeochemical Cycling in Contrasting Forests ». Soil Science Society of America Journal 59, no 5 (septembre 1995) : 1452–58. http://dx.doi.org/10.2136/sssaj1995.03615995005900050035x.

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Zepp, R. G., D. J. Erickson III, N. D. Paul et B. Sulzberger. « Interactive effects of solar UV radiation and climate change on biogeochemical cycling ». Photochemical & ; Photobiological Sciences 6, no 3 (2007) : 286. http://dx.doi.org/10.1039/b700021a.

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Ma, Deyi, Yingying Hu, Juying Wang, Sai Ye et Ai Li. « Effects of antibacterials use in aquaculture on biogeochemical processes in marine sediment ». Science of The Total Environment 367, no 1 (15 août 2006) : 273–77. http://dx.doi.org/10.1016/j.scitotenv.2005.10.014.

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Lenzi, Mauro, Maria G. Finoia, Emma Persia, Sara Comandi, Valentina Gargiulo, Duccio Solari, Paola Gennaro et Salvatore Porrello. « Biogeochemical effects of disturbance in shallow water sediment by macroalgae harvesting boats ». Marine Pollution Bulletin 50, no 5 (mai 2005) : 512–19. http://dx.doi.org/10.1016/j.marpolbul.2004.11.038.

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Kriest, I., et A. Oschlies. « Numerical effects on organic-matter sedimentation and remineralization in biogeochemical ocean models ». Ocean Modelling 39, no 3-4 (janvier 2011) : 275–83. http://dx.doi.org/10.1016/j.ocemod.2011.05.001.

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Wilske, Burkhard, Jana A. Eccard, Marcus Zistl-Schlingmann, Maximilian Hohmann, Annabel Methler, Antje Herde, Thilo Liesenjohann, Michael Dannenmann, Klaus Butterbach-Bahl et Lutz Breuer. « Effects of Short Term Bioturbation by Common Voles on Biogeochemical Soil Variables ». PLOS ONE 10, no 5 (8 mai 2015) : e0126011. http://dx.doi.org/10.1371/journal.pone.0126011.

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Yang, Fengtian, Shupeng Yue, Xiaofang Wu, Chaoyu Zhang, Dong Li et Ruijie Zhu. « Effects of flood inundation on biogeochemical processes in groundwater during riverbank filtration ». Journal of Hydrology 617 (février 2023) : 129101. http://dx.doi.org/10.1016/j.jhydrol.2023.129101.

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Schaanning, Morten Thorne, Hilde Cecilie Trannum, Sigurd Øxnevad, JoLynn Carroll et Torgeir Bakke. « Effects of drill cuttings on biogeochemical fluxes and macrobenthos of marine sediments ». Journal of Experimental Marine Biology and Ecology 361, no 1 (juin 2008) : 49–57. http://dx.doi.org/10.1016/j.jembe.2008.04.014.

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Lien, Po Jen, Hsiao Jung Ho, Tzu Hsin Lee, Wen Liang Lai et Chih Ming Kao. « Effects of Aquifer Heterogeneity and Geochemical Variation on Petroleum-Hydrocarbon Biodegradation at a Gasoline Spill Site ». Advanced Materials Research 1079-1080 (décembre 2014) : 584–88. http://dx.doi.org/10.4028/www.scientific.net/amr.1079-1080.584.

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In subsurface environment, small-scale heterogeneities usually cause the reduction of the applicability of in situ remedial techniques. Biogeochemical heterogeneities and preferential groundwater flow paths create complex hydrogeologic conditions at most contaminated sites. A thorough understanding of the resulting three-dimensional distribution of contaminants is a necessity prior to determining a need for remediation. In this study, a gasoline spill site was selected to examine the effects of aquifer heterogeneities and geochemical variations on petroleum hydrocarbon biodegradation via different oxidation-reduction process. At this site, two multilevel sampling wells were installed to delineate the lateral (5 m) and vertical (0.5 m) distribution of contaminant concentrations and different biogeochemical parameters. Two 5-cm (I.D.) continuous soil cores [from 4 to 8 m below land surface (bls)] were collected within the gasoline plume to evaluate the distribution of the microbial population in soils. Results show that high microbial activities were observed in soil samples based on the following evidences: (1) high petroleum hydrocarbon degradation rate, and (2) high microbial biomass. Each soil section was used for chemical extraction, microbial enumeration, and grain size distribution. Results show that the soil sections with more permeable sediment materials corresponded with higher biomass (total anaerobes > 2 x 106cells/g) and significant contaminant degradation. However, those sections with less permeable sediments contained lower microbial population. Results indicate that the subsurface microorganisms were distributed unevenly in the aquifer, and some regions were devoid of microorganisms and biodegradation activities. Spatial distribution of microorganisms, soil materials, and biogeochemical characteristics in the subsurface soils control the extent and kinetics of contaminant biodegradation. Thus, using blended aquifer materials for measurement of in situ biodegradation rates may not achieve representative results.
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An, Z. S., J. J. Cao, K. K. Anderson, H. Kawahata et R. Arimoto. « Biogeochemical records of past global iron connections ». Climate of the Past Discussions 2, no 3 (8 juin 2006) : 233–65. http://dx.doi.org/10.5194/cpd-2-233-2006.

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Abstract. Paleorecords of dust deposition can be used to evaluate global iron connections under conditions different from those today. Dust production and deposition has co-varied with ocean paleoproductivity, pCO2, and climate over glacial-interglacial cycles, and in this paper we review the current understanding and highlight research needs with respect to paleorecords of global iron connections. These records, which include data from terrestrial (loess) deposits, marine sediments, and ice cores, suggest that average eolian deposition rates were approximately 2–20 times higher during glacial periods than during interglacials. Enhanced dust fluxes to the oceans during glacial times, particularly to the main high-nutrient/low-chlorophyll (HNLC) areas of the open ocean (i.e., the Pacific subarctic, the equatorial Pacific, and the Southern Ocean), may have "fertilized" marine biota, thereby enhancing ocean productivity (1–2 fold) and driving atmospheric CO2 lower. Current models yield variable results, however, with glacial-interglacial changes in dust fluxes changing atmospheric pCO2 by the equivalent of 5 to >50% of the total glacial-interglacial change of 80–100 ppm. Positive correlations among Asian dust, ocean productivity and atmospheric CO2 in last 130 kyr, 1200 yr and 50 yr indicate that eolian iron has played an important role in global biogeochemical cycles of the past. A simple calculation suggests that one-tenth to one-third of the global change in CO2 due to dust-supplied Fe could be ascribed to variations in the dust supply flux from Asia and its associated effects on productivity in the Pacific Ocean.
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