Journal articles on the topic 'Biogeochemical Cover'
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Yakubov, Wallhead, Protsenko, Yakushev, Pakhomova, and Brix. "A 1-Dimensional Sympagic–Pelagic–Benthic Transport Model (SPBM): Coupled Simulation of Ice, Water Column, and Sediment Biogeochemistry, Suitable for Arctic Applications." Water 11, no. 8 (July 30, 2019): 1582. http://dx.doi.org/10.3390/w11081582.
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Marine biogeochemical processes can strongly interact with processes occurring in adjacent ice and sediments. This is especially likely in areas with shallow water and frequent ice cover, both of which are common in the Arctic. Modeling tools are therefore required to simulate coupled biogeochemical systems in ice, water, and sediment domains. We developed a 1D sympagic–pelagic–benthic transport model (SPBM) which uses input from physical model simulations to describe hydrodynamics and ice growth and modules from the Framework for Aquatic Biogeochemical Models (FABM) to construct a user-defined biogeochemical model. SPBM coupled with a biogeochemical model simulates the processes of vertical diffusion, sinking/burial, and biogeochemical transformations within and between the three domains. The potential utility of SPBM is demonstrated herein with two test runs using modules from the European regional seas ecosystem model (ERSEM) and the bottom-redox model biogeochemistry (BROM-biogeochemistry). The first run simulates multiple phytoplankton functional groups inhabiting the ice and water domains, while the second simulates detailed redox biogeochemistry in the ice, water, and sediments. SPBM is a flexible tool for integrated simulation of ice, water, and sediment biogeochemistry, and as such may help in producing well-parameterized biogeochemical models for regions with strong sympagic–pelagic–benthic interactions.
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Claussen, Martin, Victor Brovkin, and Andrey Ganopolski. "Biogeophysical versus biogeochemical feedbacks of large-scale land cover change." Geophysical Research Letters 28, no. 6 (March 15, 2001): 1011–14. http://dx.doi.org/10.1029/2000gl012471.
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Zaady, Eli, Ilan Stavi, Vladislav Dubinin, Nina Kamennaya, Hiam Abu-Glion, Shimshon Shuker, and Hezi Yizhaq. "Hillslope Geodiversity Impact on Biocrusts’ Biogeochemical Functions." Land 11, no. 11 (November 5, 2022): 1983. http://dx.doi.org/10.3390/land11111983.
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Geodiversity integrates physical parameters such as geological, geomorphological, and pedological components. It represents the abiotic diversity of the earth surface layer. It incorporates geological (bedrocks and mineral sediments), geomorphological (geography, land surface formations, physical processes), pedological (soils), and hydrological characteristics. Biological soil crusts (biocrusts) play an essential role in regulating the biogeochemical cycles of carbon and nitrogen. Their ability is dependent on habitat conditions, composition, and cover percentage of the ground surface, all of which are affected by geodiversity. This study’s objective was to assess the effects of geodiversity on the biogeochemical functions of biocrusts by regulating the soil water dynamics and the subsequent impact on readily available nitrogen and carbon. Hillslope geodiversity is determined by the geodiversity found in the stone cover on the ground surface and in the stone content throughout the soil profile, as well as by the soil profile thickness of the underlying bedrock. We hypothesized that in dry environments, the physical conditions in high-geodiversity hillslopes, compared to low-geodiversity hillslopes, positively affect the soil water budget, which would affect the biocrusts and their readily available nitrogen and carbon. The results showed higher soil moisture content in the heterogeneous hillslopes. The ammonium and labile organic carbon in the biocrusts were more substantial in the heterogeneous than in the homogeneous hillslopes, while soil protein, nitrite, and soil organic matter were similar. We suggest that the comparatively high soil moisture content in the heterogeneous hillslopes stimulates biocrust community activities and increases the readily available nitrogen and carbon, thus improving the survival of shrubs in these ecosystems under long-term drought conditions.
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Throop, Heather L., and Jayne Belnap. "Connectivity Dynamics in Dryland Litter Cycles: Moving Decomposition beyond Spatial Stasis." BioScience 69, no. 8 (July 10, 2019): 602–14. http://dx.doi.org/10.1093/biosci/biz061.
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AbstractDrylands (arid and semiarid ecosystems) cover nearly half of Earth's terrestrial surface, but biogeochemical pools and processes in these systems remain poorly understood. Litter can account for a substantial portion of carbon and nutrient pools in these systems, with litter decomposition exerting important controls over biogeochemical cycling. Dryland decomposition is typically treated as a spatially static process in which litter is retained and decomposed where it is initially deposited. Although this assumption is reasonable for mesic systems with continuous plant canopy cover and a stable subcanopy litter layer, dryland pools generally reflect discontinuous inputs from heterogeneous canopy cover followed by substantial litter transport. In the present article, we review horizontal and vertical transport processes that move litter from the initial deposition point and retention elements that influence litter accumulation patterns. Appreciation of the spatially dynamic litter cycle, including quantitative assessment of transport patterns, will improve estimates of the fate and distribution of organic matter in current and future drylands.
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Talib, Ammara, and Timothy O. Randhir. "Climate change and land use impacts on hydrologic processes of watershed systems." Journal of Water and Climate Change 8, no. 3 (March 24, 2017): 363–74. http://dx.doi.org/10.2166/wcc.2017.064.
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Land use, land cover and climate change (CC) can significantly influence the hydrologic balance and biogeochemical processes of watershed systems. These changes can alter interception, evapotranspiration (ET), infiltration, soil moisture, water balance, and biogeochemical cycling of carbon, nitrogen, and other elements. The need to evaluate the combined effect of land use change and CC of watershed systems is a focus of this study. We simulated watershed processes in the SuAsCo River watershed in MA, USA, using a calibrated and validated Hydrological Simulation Program Fortran model. Climatic scenarios included downscaled regional projections from Global Climate Model models. The Land Transformation Model was used to project land use. Combined change in land cover and climate reduce ET with loss of vegetation. Changes in climate and land cover increase surface runoff significantly by 2100 as well as stream discharge. Combined change in land cover and climate cause 10% increase in peak volume with 7% increase in precipitation and 75% increase in effective impervious area. Climate and land use changes can intensify the water cycle and introduce seasonal changes in watershed systems. Understanding dynamic changes in watershed systems is critical for mitigation and adaptation options. We propose restoration strategies that can increase the resilience of watershed systems.
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Dieye, A. M., D. P. Roy, N. P. Hanan, S. Liu, M. Hansen, and A. Touré. "Sensitivity analysis of the GEMS soil organic carbon model to land cover land use classification uncertainties under different climate scenarios in Senegal." Biogeosciences Discussions 8, no. 4 (July 8, 2011): 6589–635. http://dx.doi.org/10.5194/bgd-8-6589-2011.
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Abstract. Spatially explicit land cover land use (LCLU) change information is needed to drive biogeochemical models that simulate soil organic carbon (SOC) dynamics. Such information is increasingly being mapped using remotely sensed satellite data with classification schemes and uncertainties constrained by the sensing system, classification algorithms and land cover schemes. In this study, automated LCLU classification of multi-temporal Landsat satellite data were used to assess the sensitivity of SOC modeled by the Global Ensemble Biogeochemical Modeling System (GEMS). The GEMS was run for an area of 1560 km2 in Senegal under three climate change scenarios with LCLU maps generated using different Landsat classification approaches. This research provides a method to estimate the variability of SOC, specifically the SOC uncertainty due to satellite classification errors, which we show is dependent not only on the LCLU classification errors but also on where the LCLU classes occur relative to the other GEMS model inputs.
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Dieye, A. M., D. P. Roy, N. P. Hanan, S. Liu, M. Hansen, and A. Touré. "Sensitivity analysis of the GEMS soil organic carbon model to land cover land use classification uncertainties under different climate scenarios in senegal." Biogeosciences 9, no. 2 (February 3, 2012): 631–48. http://dx.doi.org/10.5194/bg-9-631-2012.
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Abstract. Spatially explicit land cover land use (LCLU) change information is needed to drive biogeochemical models that simulate soil organic carbon (SOC) dynamics. Such information is increasingly being mapped using remotely sensed satellite data with classification schemes and uncertainties constrained by the sensing system, classification algorithms and land cover schemes. In this study, automated LCLU classification of multi-temporal Landsat satellite data were used to assess the sensitivity of SOC modeled by the Global Ensemble Biogeochemical Modeling System (GEMS). The GEMS was run for an area of 1560 km2 in Senegal under three climate change scenarios with LCLU maps generated using different Landsat classification approaches. This research provides a method to estimate the variability of SOC, specifically the SOC uncertainty due to satellite classification errors, which we show is dependent not only on the LCLU classification errors but also on where the LCLU classes occur relative to the other GEMS model inputs.
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Mahmood, Rezaul, Roger A. Pielke, and Clive A. McAlpine. "Climate-Relevant Land Use and Land Cover Change Policies." Bulletin of the American Meteorological Society 97, no. 2 (February 1, 2016): 195–202. http://dx.doi.org/10.1175/bams-d-14-00221.1.
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Abstract Both observational and modeling studies clearly demonstrate that land-use and land-cover change (LULCC) play an important biogeophysical and biogeochemical role in the climate system from the landscape to regional and even continental scales. Without comprehensively considering these impacts, an adequate response to the threats posed by human intervention into the climate system will not be adequate. Public policy plays an important role in shaping local- to national-scale land-use practices. An array of national policies has been developed to influence the nature and spatial extent of LULCC. Observational evidence suggests that these policies, in addition to international trade treaties and protocols, have direct effects on LULCC and thus the climate system. However, these policies, agreements, and protocols fail to adequately recognize these impacts. To make these more effective and thus to minimize climatic impacts, we propose several recommendations: 1) translating international treaties and protocols into national policies and actions to ensure positive climate outcomes; 2) updating international protocols to reflect advancement in climate–LULCC science; 3) continuing to invest in the measurements, databases, reporting, and verification activities associated with LULCC and LULCC-relevant climate monitoring; and 4) reshaping Reducing Emissions from Deforestation and Forest Degradation+ (REDD+) to fully account for the multiscale biogeophysical and biogeochemical impacts of LULCC on the climate system.
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Sibgatullina, Madina, and Vsevolod Valiev. "Trace elements in wild plants of the Lower Kama national park." SOCIALNO-ECOLOGICHESKIE TECHNOLOGII 9, no. 3 (2019): 325–42. http://dx.doi.org/10.31862/2500-2961-2019-9-3-325-342.
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Biogeochemical studies of plants and soil cover in specially protected natural areas are necessary for conducting background geochemical monitoring in order to determine the content of trace elements in plants of natural ecosystems and to establish the relationship between trace element composition and environmental factors. The atomic absorption spectrophotometry was used to determine the content of trace elements Mn, Fe, Zn, Cu, Cr, Co, Ni, Cd, Pb in wild herbaceous plants and the root layer of soil in the Nizhny Kama National Park (Kama valley and its tributaries). Species with a high content of Ni were found. High concentrations of Fe, Cr, Pb in the phytomass of mosses were revealed, which may indicate their aerogenic supply from nearby industrial enterprises. It was established that the soil cover of the national park within the Yelabuga region is characterized by an increased content of Mn and Co. The trace elements that are vigorously absorbed by plants, as well as species characterized by high biogeochemical activity have been identified – Aegopodium podagraria L., Fragaria vesca L., Paris quadrifolia L., Anemonoides ranunculoides L., Dicranum Hedw
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Chen, Ning, Kailiang Yu, Rongliang Jia, Jialing Teng, and Changming Zhao. "Biocrust as one of multiple stable states in global drylands." Science Advances 6, no. 39 (September 2020): eaay3763. http://dx.doi.org/10.1126/sciadv.aay3763.
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Biocrusts cover ~30% of global drylands with a prominent role in the biogeochemical cycles. Theoretically, biocrusts, vascular plants, and bare soil can represent multiple stable states in drylands. However, no empirical evidence for the existence of a biocrust stable state has been reported. Here, using a global drylands dataset, we found that biocrusts form an alternative stable state (biocrust cover, ~80%; vascular cover, ≤10%) besides bare soil (both biocrust and vascular cover, ≤10%) and vascular plants (vascular cover, >50%; biocrust cover, ~5%). The pattern of multiple stable states associated with biocrusts differs from the classic fold bifurcation, and values of the aridity index in the range of 0 to 0.6 define a bistable region where multiple stable states coexist. This study empirically demonstrates the existence and thresholds of multiple stable states associated with biocrusts along climatic gradients and thus may greatly contribute to conservation and restoration of global drylands.
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Leslie, Karla, Pim W. G. van Geffen, Bill MacFarlane, Christopher J. Oates, T. Kurt Kyser, and David A. Fowle. "Biogeochemical indicators of buried mineralization under cover, Talbot VMS Cu–Zn prospect, Manitoba." Applied Geochemistry 37 (October 2013): 190–202. http://dx.doi.org/10.1016/j.apgeochem.2013.07.013.
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Gasser, Thomas, Léa Crepin, Yann Quilcaille, Richard A. Houghton, Philippe Ciais, and Michael Obersteiner. "Historical CO<sub>2</sub> emissions from land use and land cover change and their uncertainty." Biogeosciences 17, no. 15 (August 13, 2020): 4075–101. http://dx.doi.org/10.5194/bg-17-4075-2020.
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Abstract. Emissions from land use and land cover change are a key component of the global carbon cycle. However, models are required to disentangle these emissions from the land carbon sink, as only the sum of both can be physically observed. Their assessment within the yearly community-wide effort known as the “Global Carbon Budget” remains a major difficulty, because it combines two lines of evidence that are inherently inconsistent: bookkeeping models and dynamic global vegetation models. Here, we propose a unifying approach that relies on a bookkeeping model, which embeds processes and parameters calibrated on dynamic global vegetation models, and the use of an empirical constraint. We estimate that the global CO2 emissions from land use and land cover change were 1.36±0.42 PgC yr−1 (1σ range) on average over the 2009–2018 period and reached a cumulative total of 206±57 PgC over the 1750–2018 period. We also estimate that land cover change induced a global loss of additional sink capacity – that is, a foregone carbon removal, not part of the emissions – of 0.68±0.57 PgC yr−1 and 32±23 PgC over the same periods, respectively. Additionally, we provide a breakdown of our results' uncertainty, including aspects such as the land use and land cover change data sets used as input and the model's biogeochemical parameters. We find that the biogeochemical uncertainty dominates our global and regional estimates with the exception of tropical regions in which the input data dominates. Our analysis further identifies key sources of uncertainty and suggests ways to strengthen the robustness of future Global Carbon Budget estimates.
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Almeida, Teodoro I. R., Maria do Carmo Calijuri, Patrícia B. Falco, Simone P. Casali, Elena Kupriyanova, Antonio C. Paranhos Filho, Joel B. Sigolo, and Reginaldo A. Bertolo. "Biogeochemical processes and the diversity of Nhecolândia lakes, Brazil." Anais da Academia Brasileira de Ciências 83, no. 2 (June 2011): 391–407. http://dx.doi.org/10.1590/s0001-37652011000200004.
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The Pantanal of Nhecolândia, the world's largest and most diversified field of tropical lakes, comprises approximately 10,000 lakes, which cover an area of 24,000 km² and vary greatly in salinity, pH, alkalinity, colour, physiography and biological activity. The hyposaline lakes have variable pHs, low alkalinity, macrophytes and low phytoplankton densities. The saline lakes have pHs above 9 or 10, high alkalinity, a high density of phytoplankton and sand beaches. The cause of the diversity of these lakes has been an open question, which we have addressed in our research. Here we propose a hybrid process, both geochemical and biological, as the main cause, including (1) a climate with an important water deficit and poverty in Ca2+ in both superficial and phreatic waters; and (2) an elevation of pH during cyanobacteria blooms. These two aspects destabilise the general tendency of Earth's surface waters towards a neutral pH. This imbalance results in an increase in the pH and dissolution of previously precipitated amorphous silica and quartzose sand. During extreme droughts, amorphous silica precipitates in the inter-granular spaces of the lake bottom sediment, increasing the isolation of the lake from the phreatic level. This paper discusses this biogeochemical problem in the light of physicochemical, chemical, altimetric and phytoplankton data.
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Dietrich, Sebastian T., and M. Derek MacKenzie. "Biochar affects aspen seedling growth and reclaimed soil properties in the Athabasca oil sands region." Canadian Journal of Soil Science 98, no. 3 (September 1, 2018): 519–30. http://dx.doi.org/10.1139/cjss-2017-0113.
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Restoring ecosystem function after oil sands surface mining involves reestablishing the biotic and abiotic ecosystem components that affect biogeochemical cycles and fluxes. In boreal forest ecosystems, pyrogenic carbon is a native soil component that affects a variety of biogeochemical parameters and biochar is its human-made analog. To evaluate the benefits of biochar amendment to reclamation cover soils, we compared characteristics and function of peat–mineral mix (PM) and forest floor–mineral mix (FFM) with and without biochar in an 18 wk greenhouse study. We assessed nutrient bioavailability (NO3, NH4, P, K, S, Mg, and Ca), foliar nutrient concentrations (N, P, K, S, Mg, Ca, Na, and Mo), soil respiration, rhizosphere polysaccharide concentration, soil organic matter stability, and Populus tremuloides Michx. seedling growth. Seedling growth increased significantly on PM cover soil with biochar. Biochar improved K nutritional status and potentially interacted with Na bioavailability in PM, affecting growth. Soil respiration significantly decreased in PM with biochar and increased in FFM. Soil organic matter stability was positively correlated with seedling growth and increased with biochar. Our findings suggest that biochar may have a significant positive effect on upland forest reclamation in the Athabasca oil sands region, especially on sites that are reclaimed with PM.
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Morée, Anne L., Jörg Schwinger, and Christoph Heinze. "Southern Ocean controls of the vertical marine <i>δ</i><sup>13</sup>C gradient – a modelling study." Biogeosciences 15, no. 23 (December 4, 2018): 7205–23. http://dx.doi.org/10.5194/bg-15-7205-2018.
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Abstract. δ13C, the standardised 13C ∕ 12C ratio expressed in per mille, is a widely used ocean tracer to study changes in ocean circulation, water mass ventilation, atmospheric pCO2, and the biological carbon pump on timescales ranging from decades to tens of millions of years. δ13C data derived from ocean sediment core analysis provide information on δ13C of dissolved inorganic carbon and the vertical δ13C gradient (i.e. Δδ13C) in past oceans. In order to correctly interpret δ13C and Δδ13C variations, a good understanding is needed of the influence from ocean circulation, air–sea gas exchange and biological productivity on these variations. The Southern Ocean is a key region for these processes, and we show here that Δδ13C in all ocean basins is sensitive to changes in the biogeochemical state of the Southern Ocean. We conduct a set of idealised sensitivity experiments with the ocean biogeochemistry general circulation model HAMOCC2s to explore the effect of biogeochemical state changes of the Southern and Global Ocean on atmospheric δ13C, pCO2, and marine δ13C and Δδ13C. The experiments cover changes in air–sea gas exchange rates, particulate organic carbon sinking rates, sea ice cover, and nutrient uptake efficiency in an unchanged ocean circulation field. Our experiments show that global mean Δδ13C varies by up to about ±0.35 ‰ around the pre-industrial model reference (1.2 ‰) in response to biogeochemical change. The amplitude of this sensitivity can be larger at smaller scales, as seen from a maximum sensitivity of about −0.6 ‰ on ocean basin scale. The ocean's oldest water (North Pacific) responds most to biological changes, the young deep water (North Atlantic) responds strongly to air–sea gas exchange changes, and the vertically well-mixed water (SO) has a low or even reversed Δδ13C sensitivity compared to the other basins. This local Δδ13C sensitivity depends on the local thermodynamic disequilibrium and the Δδ13C sensitivity to local POC export production changes. The direction of both glacial (intensification of Δδ13C) and interglacial (weakening of Δδ13C) Δδ13C change matches the direction of the sensitivity of biogeochemical processes associated with these periods. This supports the idea that biogeochemistry likely explains part of the reconstructed variations in Δδ13C, in addition to changes in ocean circulation.
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Ponette-González, A. G., K. C. Weathers, and L. M. Curran. "Tropical land-cover change alters biogeochemical inputs to ecosystems in a Mexican montane landscape." Ecological Applications 20, no. 7 (October 2010): 1820–37. http://dx.doi.org/10.1890/09-1125.1.
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Gammons, Christopher H., William Henne, Simon R. Poulson, Stephen R. Parker, Tyler B. Johnston, John E. Dore, and Eric S. Boyd. "Stable isotopes track biogeochemical processes under seasonal ice cover in a shallow, productive lake." Biogeochemistry 120, no. 1-3 (June 28, 2014): 359–79. http://dx.doi.org/10.1007/s10533-014-0005-z.
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Shergina, O. V., T. A. Mikhailova, and A. S. Mironova. "Assessment of regulating ecosystem functions/services of the urban forests in the Angara region (Eastern Siberia, Russia)." IOP Conference Series: Earth and Environmental Science 908, no. 1 (November 1, 2021): 012042. http://dx.doi.org/10.1088/1755-1315/908/1/012042.
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Abstract The studies of urban forests were carried out on the territory of the Angara region in cities with a high air pollution index (up to 20) and with a high recreational load. The state of forest biogeocenoses was assessed by the parameters of trees, forest litter, and soil. Morphostructural, physicochemical, biochemical, and toxicological indicators were analysed. It was found that the selected biogeochemical parameters of trees and soils have a high level of correlation relationships under conditions of negative anthropogenic impact. The biogeochemical redistribution of technogenic pollutants in urban forests connects with the accumulating capacity of the soil cover and the regulatory function of trees, namely the ability to purify atmospheric air by accumulating toxicants in the needles and leaves. Regulatory function/service of pollutant absorption and air purification depends not only on the condition of urban forests, it is unequal for forests of different cities and, even more, for different forested territories.
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Hill, J., E. E. Popova, D. A. Ham, M. D. Piggott, and M. Srokosz. "Adapting to life: ocean biogeochemical modelling and adaptive remeshing." Ocean Science Discussions 10, no. 6 (November 5, 2013): 1997–2051. http://dx.doi.org/10.5194/osd-10-1997-2013.
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Abstract. An outstanding problem in biogeochemical modelling of the ocean is that many of the key processes occur intermittently at small scales, such as the sub-mesoscale, that are not well represented in global ocean models. As an example, state-of-the-art models give values of primary production approximately two orders of magnitude lower than those observed in the ocean's oligotrophic gyres, which cover a third of the Earth's surface. This is partly due to their failure to resolve sub-mesoscale phenomena, which play a significant role in nutrient supply. Simply increasing the resolution of the models may be an inefficient computational solution to this problem. An approach based on recent advances in adaptive mesh computational techniques may offer an alternative. Here the first steps in such an approach are described, using the example of a~simple vertical column (quasi 1-D) ocean biogeochemical model. We present a novel method of simulating ocean biogeochemical behaviour on a vertically adaptive computational mesh, where the mesh changes in response to the biogeochemical and physical state of the system throughout the simulation. We show that the model reproduces the general physical and biological behaviour at three ocean stations (India, Papa and Bermuda) as compared to a high-resolution fixed mesh simulation and to observations. The simulations capture both the seasonal and inter-annual variations. The use of an adaptive mesh does not increase the computational error, but reduces the number of mesh elements by a factor of 2–3, so reducing computational overhead. We then show the potential of this method in two case studies where we change the metric used to determine the varying mesh sizes in order to capture the dynamics of chlorophyll at Bermuda and sinking detritus at Papa. We therefore demonstrate adaptive meshes may provide a~suitable numerical technique for simulating seasonal or transient biogeochemical behaviour at high spatial resolution whilst minimising computational cost.
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Zhi, Wei, Yuning Shi, Hang Wen, Leila Saberi, Gene-Hua Crystal Ng, Kayalvizhi Sadayappan, Devon Kerins, Bryn Stewart, and Li Li. "BioRT-Flux-PIHM v1.0: a biogeochemical reactive transport model at the watershed scale." Geoscientific Model Development 15, no. 1 (January 17, 2022): 315–33. http://dx.doi.org/10.5194/gmd-15-315-2022.
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Abstract. Watersheds are the fundamental Earth surface functioning units that connect the land to aquatic systems. Many watershed-scale models represent hydrological processes but not biogeochemical reactive transport processes. This has limited our capability to understand and predict solute export, water chemistry and quality, and Earth system response to changing climate and anthropogenic conditions. Here we present a recently developed BioRT-Flux-PIHM (BioRT hereafter) v1.0, a watershed-scale biogeochemical reactive transport model. The model augments the previously developed RT-Flux-PIHM that integrates land-surface interactions, surface hydrology, and abiotic geochemical reactions. It enables the simulation of (1) shallow and deep-water partitioning to represent surface runoff, shallow soil water, and deeper groundwater and of (2) biotic processes including plant uptake, soil respiration, and nutrient transformation. The reactive transport part of the code has been verified against the widely used reactive transport code CrunchTope. BioRT-Flux-PIHM v1.0 has recently been applied in multiple watersheds under diverse climate, vegetation, and geological conditions. This paper briefly introduces the governing equations and model structure with a focus on new aspects of the model. It also showcases one hydrology example that simulates shallow and deep-water interactions and two biogeochemical examples relevant to nitrate and dissolved organic carbon (DOC). These examples are illustrated in two simulation modes of complexity. One is the spatially lumped mode (i.e., two land cells connected by one river segment) that focuses on processes and average behavior of a watershed. Another is the spatially distributed mode (i.e., hundreds of cells) that includes details of topography, land cover, and soil properties. Whereas the spatially lumped mode represents averaged properties and processes and temporal variations, the spatially distributed mode can be used to understand the impacts of spatial structure and identify hot spots of biogeochemical reactions. The model can be used to mechanistically understand coupled hydrological and biogeochemical processes under gradients of climate, vegetation, geology, and land use conditions.
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Morata, Nathalie, Emma Michaud, Marie-Aude Poullaouec, Jérémy Devesa, Manon Le Goff, Rudolph Corvaisier, and Paul E. Renaud. "Climate change and diminishing seasonality in Arctic benthic processes." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, no. 2181 (August 31, 2020): 20190369. http://dx.doi.org/10.1098/rsta.2019.0369.
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The iconic picture of Arctic marine ecosystems shows an intense pulse of biological productivity around the spring bloom that is sustained while fresh organic matter (OM) is available, after which ecosystem activity declines to basal levels in autumn and winter. We investigated seasonality in benthic biogeochemical cycling at three stations in a high Arctic fjord that has recently lost much of its seasonal ice-cover. Unlike observations from other Arctic locations, we find little seasonality in sediment community respiration and bioturbation rates, although different sediment reworking modes varied through the year. Nutrient fluxes did vary, suggesting that, although OM was processed at similar rates, seasonality in its quality led to spring/summer peaks in inorganic nitrogen and silicate fluxes. These patterns correspond to published information on seasonality in vertical flux at the stations. Largely ice-free Kongsfjorden has a considerable detrital pool in soft sediments which sustain benthic communities over the year. Sources of this include macroalgae and terrestrial runoff. Climate change leading to less ice cover, higher light availability and expanded benthic habitat may lead to more detrital carbon in the system, dampening the quantitative importance of seasonal pulses of phytodetritus to seafloor communities in some areas of the Arctic. This article is part of the theme issue ‘The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.
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Hague, Mark, and Marcello Vichi. "Southern Ocean Biogeochemical Argo detect under-ice phytoplankton growth before sea ice retreat." Biogeosciences 18, no. 1 (January 4, 2021): 25–38. http://dx.doi.org/10.5194/bg-18-25-2021.
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Abstract. The seasonality of sea ice in the Southern Ocean has profound effects on the life cycle (phenology) of phytoplankton residing under the ice. The current literature investigating this relationship is primarily based on remote sensing, which often lacks data for half of the year or more. One prominent hypothesis holds that, following ice retreat in spring, buoyant meltwaters enhance available irradiance, triggering a bloom which follows the ice edge. However, an analysis of Biogeochemical Argo (BGC-Argo) data sampling under Antarctic sea ice suggests that this is not necessarily the case. Rather than precipitating rapid accumulation, we show that meltwaters enhance growth in an already highly active phytoplankton population. Blooms observed in the wake of the receding ice edge can then be understood as the emergence of a growth process that started earlier under sea ice. Indeed, we estimate that growth initiation occurs, on average, 4–5 weeks before ice retreat, typically starting in August and September. Novel techniques using on-board data to detect the timing of ice melt were used. Furthermore, such growth is shown to occur under conditions of substantial ice cover (>90 % satellite ice concentration) and deep mixed layers (>100 m), conditions previously thought to be inimical to growth. This led to the development of several box model experiments (with varying vertical depth) in which we sought to investigate the mechanisms responsible for such early growth. The results of these experiments suggest that a combination of higher light transfer (penetration) through sea ice cover and extreme low light adaptation by phytoplankton can account for the observed phenology.
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Chetri, Jyoti K., Krishna R. Reddy, and Stefan J. Green. "Use of methanotrophically activated biochar in novel biogeochemical cover system for carbon sequestration: Microbial characterization." Science of The Total Environment 821 (May 2022): 153429. http://dx.doi.org/10.1016/j.scitotenv.2022.153429.
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Mandernack, Kevin W., Thomas Rahn, Chad Kinney, and Martin Wahlen. "The biogeochemical controls of the δ15N and δ18O of N2O produced in landfill cover soils." Journal of Geophysical Research: Atmospheres 105, no. D14 (July 1, 2000): 17709–20. http://dx.doi.org/10.1029/2000jd900055.
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de Graaff, Marie-Anne, Heather L. Throop, Paul S. J. Verburg, John A. Arnone, and Xochi Campos. "A Synthesis of Climate and Vegetation Cover Effects on Biogeochemical Cycling in Shrub-Dominated Drylands." Ecosystems 17, no. 5 (March 18, 2014): 931–45. http://dx.doi.org/10.1007/s10021-014-9764-6.
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Tison, J. ‐L, S. Schwegmann, G. Dieckmann, J. ‐M Rintala, H. Meyer, S. Moreau, M. Vancoppenolle, et al. "Biogeochemical Impact of Snow Cover and Cyclonic Intrusions on the Winter Weddell Sea Ice Pack." Journal of Geophysical Research: Oceans 122, no. 12 (December 2017): 9548–71. http://dx.doi.org/10.1002/2017jc013288.
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Zhao, S., S. Liu, Z. Li, and T. L. Sohl. "A spatial resolution threshold of land cover in estimating regional terrestrial carbon sequestration." Biogeosciences Discussions 6, no. 4 (August 5, 2009): 7983–8006. http://dx.doi.org/10.5194/bgd-6-7983-2009.
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Abstract. Changes in carbon density (i.e., carbon stock per unit area) and land cover greatly affect carbon sequestration. Previous studies have shown that land cover change detection strongly depends on spatial scale. However, the influence of the spatial resolution of land cover change information on the estimated terrestrial carbon sequestration is not known. Here, we quantified and evaluated the impact of land cover change databases at various spatial resolutions (250 m, 500 m, 1 km, 2 km, and 4 km) on the magnitude and spatial patterns of regional carbon sequestration in the southeastern United States using the General Ensemble biogeochemical Modeling System (GEMS). Results indicated a threshold of 1 km in the land cover change databases and in the estimated regional terrestrial carbon sequestration. Beyond this threshold, significant biases occurred in the estimation of terrestrial carbon sequestration, its interannual variability, and spatial patterns. In addition, the overriding impact of interannual climate variability on the temporal change of regional carbon sequestration was unrealistically overshadowed by the impact of land cover change beyond the threshold. The implications of these findings directly challenge current continental- to global-scale carbon modeling efforts relying on information at coarse spatial resolution without incorporating fine-scale land cover dynamics.
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Zhao, S. Q., S. Liu, Z. Li, and T. L. Sohl. "A spatial resolution threshold of land cover in estimating terrestrial carbon sequestration in four counties in Georgia and Alabama, USA." Biogeosciences 7, no. 1 (January 7, 2010): 71–80. http://dx.doi.org/10.5194/bg-7-71-2010.
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Abstract. Changes in carbon density (i.e., carbon stock per unit area) and land cover greatly affect carbon sequestration. Previous studies have shown that land cover change detection strongly depends on spatial scale. However, the influence of the spatial resolution of land cover change information on the estimated terrestrial carbon sequestration is not known. Here, we quantified and evaluated the impact of land cover change databases at various spatial resolutions (250 m, 500 m, 1 km, 2 km, and 4 km) on the magnitude and spatial patterns of regional carbon sequestration in four counties in Georgia and Alabama using the General Ensemble biogeochemical Modeling System (GEMS). Results indicated a threshold of 1 km in the land cover change databases and in the estimated regional terrestrial carbon sequestration. Beyond this threshold, significant biases occurred in the estimation of terrestrial carbon sequestration, its interannual variability, and spatial patterns. In addition, the overriding impact of interannual climate variability on the temporal change of regional carbon sequestration was unrealistically overshadowed by the impact of land cover change beyond the threshold. The implications of these findings directly challenge current continental- to global-scale carbon modeling efforts relying on information at coarse spatial resolution without incorporating fine-scale land cover dynamics.
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Quideau, S. A., M. J. B. Swallow, C. E. Prescott, S. J. Grayston, and S. W. Oh. "Comparing soil biogeochemical processes in novel and natural boreal forest ecosystems." Biogeosciences 10, no. 8 (August 27, 2013): 5651–61. http://dx.doi.org/10.5194/bg-10-5651-2013.
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Abstract. Emulating the variability that exists in the natural landscape prior to disturbance should be a goal of soil reconstruction and land reclamation efforts following resource extraction. Long-term ecosystem sustainability within reclaimed landscapes can only be achieved with the re-establishment of biogeochemical processes between reconstructed soils and plants. In this study, we assessed key soil biogeochemical attributes (nutrient availability, organic matter composition, and microbial communities) in reconstructed, novel, anthropogenic ecosystems, covering different reclamation treatments following open-cast mining for oil extraction. We compared the attributes to those present in a range of natural soils representative of mature boreal forest ecosystems in the same area of Northern Alberta. Soil nutrient availability was determined in situ with resin probes, organic matter composition was described with 13C nuclear magnetic resonance spectroscopy and soil microbial community structure was characterized using phospholipid fatty acid analysis. Significant differences among natural ecosystems were apparent in nutrient availability and seemed more related to the dominant tree cover than to soil type. When analyzed together, all natural forests differed significantly from the novel ecosystems, in particular with respect to soil organic matter composition. However, there was some overlap between the reconstructed soils and some of the natural ecosystems in nutrient availability and microbial communities, but not in organic matter characteristics. Hence, our results illustrate the importance of considering the range of natural landscape variability and including several soil biogeochemical attributes when comparing novel, anthropogenic ecosystems to the mature ecosystems that constitute ecological targets.
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Quideau, S. A., M. J. B. Swallow, C. E. Prescott, S. J. Grayston, and S. W. Oh. "Comparing soil biogeochemical processes in novel and natural boreal forest ecosystems." Biogeosciences Discussions 10, no. 4 (April 30, 2013): 7521–48. http://dx.doi.org/10.5194/bgd-10-7521-2013.
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Abstract. Emulating the variability that exists in the natural landscape prior to disturbance should be a goal of soil reconstruction and land reclamation efforts following resource extraction. Long-term ecosystem sustainability within reclaimed landscapes can only be achieved with the re-establishment of biogeochemical processes between reconstructed soils and plants. In this study, we assessed key soil biogeochemical attributes (nutrient availability, organic matter composition, and microbial communities) in reconstructed, novel, anthropogenic ecosystems covering different reclamation treatments following open-cast mining for oil extraction. We compared the attributes to those present in a range of natural soils representative of mature boreal forest ecosystems in the same area of northern Alberta. Soil nutrient availability was determined in situ with resin probes, organic matter composition was described with 13C nuclear magnetic resonance spectroscopy and soil microbial community structure was characterized using phospholipid fatty acid analysis. Significant differences among natural ecosystems were apparent in nutrient availability and seemed more related to the dominant tree cover than to soil type. When analyzed together, all natural forests differed significantly from the novel ecosystems, in particular with respect to soil organic matter composition. However, there was some overlap between the reconstructed soils and some of the natural ecosystems in nutrient availability and microbial communities, but not in organic matter characteristics. Hence, our results illustrate the importance of considering the range of natural landscape variability, and including several soil biogeochemical attributes when comparing novel, anthropogenic ecosystems to the mature ecosystems that constitute ecological targets.
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MACIAS, D. M., C. T. GUERREIRO, L. PRIETO, A. PELIZ, and J. RUIZ. "A high-resolution hydrodynamic-biogeochemical coupled model of the Gulf of Cadiz – Alboran Sea region." Mediterranean Marine Science 15, no. 4 (December 22, 2014): 739. http://dx.doi.org/10.12681/mms.841.
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The southern Iberia regional seas comprise the Gulf of Cadiz and the Alboran Sea sub-basins connected by the narrow Strait of Gibraltar. Both basins are very different in their hydrological and biological characteristics but are, also, tightly connected to each other. Integrative studies of the whole regional oceanic system are scarce and difficult to perform due to the relative large area to cover and the different relevant time-scales of the main forcings in each sub-basin. Here we propose, for the first time, a fully coupled, 3D, hydrodynamic-biogeochemical model that covers, in a single domain (~2km resolution) both marine basins for a 20 years simulation (1989-2008). Model performance is assessed against available data in terms of spatial and temporal distributions of biological variables. In general, the proposed model is able to represent the climatological distributions of primary and secondary producers and also the main seasonality of primary production in the different sub-regions of the analyzed basins. Potential causes of the observed mismatches between model and data are identified and some solutions are proposed for future model development. We conclude that most of these mismatches could be attributed to the missing tidal forcing in the actual model configuration. This model is a first step to obtain a meaningful tool to study past and future oceanographic conditions in this important marine region constituting the unique connection of the Mediterranean Sea with the open world’s ocean.
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Boereboom, T., M. Depoorter, S. Coppens, and J. L. Tison. "Gas properties of winter lake ice in Northern Sweden: biogeochemical processes and implication for carbon gas release." Biogeosciences Discussions 8, no. 5 (September 27, 2011): 9639–69. http://dx.doi.org/10.5194/bgd-8-9639-2011.
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Abstract. This paper describes gas composition, total gas content and bubbles characteristics in winter lake ice for four adjacent lakes in a discontinuous permafrost area. Our gas mixing ratios suggest that gas exchange occurs between the bubbles and the water before entrapment in the ice. Comparison between lakes enabled us to identify 2 major "bubbling events" shown to be related to a regional drop of atmospheric pressure. Further comparison demonstrates that winter lake gas content is strongly dependent on hydrological connections: according to their closed/open status with regards to water exchange, lakes build up more or less greenhouse gases (GHG) in their water and ice cover during the winter, and release it during spring melt. These discrepancies between lakes need to be taken into account when establishing a budget for permafrost regions. Our analysis allows us to present a new classification of bubbles, according to their gas properties. Our methane emission budget (from 6.52 10−5 to 12.7 mg CH4 m−2 d−1) for the three months of winter ice cover is complementary to the other budget estimates, taking into account the variability of the gas distribution in the ice and between the various types of lakes. Most available studies on boreal lakes have focused on quantifying GHG emissions from sediment by means of various systems collecting gases at the lake surface, and this mainly during the summer "open water" period. Only few of these have looked at the gas enclosed in the winter ice-cover itself. Our approach enables us to integrate, for the first time, the history of winter gas emission for this type of lakes.
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Wang, Lang, Amos P. K. Tai, Chi-Yung Tam, Mehliyar Sadiq, Peng Wang, and Kevin K. W. Cheung. "Impacts of future land use and land cover change on mid-21st-century surface ozone air quality: distinguishing between the biogeophysical and biogeochemical effects." Atmospheric Chemistry and Physics 20, no. 19 (October 5, 2020): 11349–69. http://dx.doi.org/10.5194/acp-20-11349-2020.
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Abstract. Surface ozone (O3) is an important air pollutant and greenhouse gas. Land use and land cover is one of the critical factors influencing ozone, in addition to anthropogenic emissions and climate. Land use and land cover change (LULCC) can on the one hand affect ozone “biogeochemically”, i.e., via dry deposition and biogenic emissions of volatile organic compounds (VOCs). LULCC can on the other hand alter regional- to large-scale climate through modifying albedo and evapotranspiration, which can lead to changes in surface temperature, hydrometeorology, and atmospheric circulation that can ultimately impact ozone “biogeophysically”. Such biogeophysical effects of LULCC on ozone are largely understudied. This study investigates the individual and combined biogeophysical and biogeochemical effects of LULCC on ozone and explicitly examines the critical pathway for how LULCC impacts ozone pollution. A global coupled atmosphere–chemistry–land model is driven by projected LULCC from the present day (2000) to the future (2050) under RCP4.5 and RCP8.5 scenarios, focusing on the boreal summer. Results reveal that when considering biogeochemical effects only, surface ozone is predicted to have slight changes by up to 2 ppbv maximum in some areas due to LULCC. It is primarily driven by changes in isoprene emission and dry deposition counteracting each other in shaping ozone. In contrast, when considering the combined effect of LULCC, ozone is more substantially altered by up to 5 ppbv over several regions in North America and Europe under RCP4.5, reflecting the importance of biogeophysical effects on ozone changes. In boreal and temperate mixed forests with intensive reforestation, enhanced net radiation and sensible heat induce a cascade of hydrometeorological feedbacks that generate warmer and drier conditions favorable for higher ozone levels. In contrast, reforestation in subtropical broadleaf forests has minimal impacts on boundary-layer meteorology and ozone air quality. Furthermore, significant ozone changes are also found in regions with only modest LULCC, which can only be explained by “remote” biogeophysical effects. A likely mechanism is that reforestation induces a circulation response, leading to reduced moisture transport and ultimately warmer and drier conditions in the surrounding regions with limited LULCC. We conclude that the biogeophysical effects of LULCC are important pathways through which LULCC influences ozone air quality both locally and in remote regions even without significant LULCC. Overlooking the effects of hydrometeorological changes on ozone air quality may cause underestimation of the impacts of LULCC on ozone pollution.
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Ito, A., J. E. Penner, M. J. Prather, C. P. de Campos, R. A. Houghton, T. Kato, A. K. Jain, et al. "Can we reconcile differences in estimates of carbon fluxes from land-use change and forestry for the 1990s?" Atmospheric Chemistry and Physics Discussions 8, no. 1 (February 25, 2008): 3843–93. http://dx.doi.org/10.5194/acpd-8-3843-2008.
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Abstract. The effect of Land Use Change and Forestry (LUCF) on terrestrial carbon fluxes can be regarded as a carbon credit or debit under the UNFCCC, but scientific uncertainty in the estimates for LUCF remains large. Here, we assess the LUCF estimates by examining a variety of models of different types with different land cover change maps in the 1990s. Annual carbon pools and their changes are separated into different components for separate geographical regions, while annual land cover change areas and carbon fluxes are disaggregated into different LUCF activities and the biospheric response due to CO2 fertilization and climate change. We developed a consolidated estimate of the terrestrial carbon fluxes that combines book-keeping models with process-based biogeochemical models and inventory estimates and yields an estimate of the global terrestrial carbon flux that is within the uncertainty range developed in the IPCC 4th Assessment Report. We examined the USA and Brazil as case studies in order to assess the cause of differences from the UNFCCC reported carbon fluxes. Major differences in the litter and soil organic matter components are found for the USA. Differences in Brazil result from assumptions about the LUC for agricultural purposes. The effects of CO2 fertilization and climate change also vary significantly in Brazil. Our consolidated estimate shows that the small sink in Latin America is within the uncertainty range from inverse models, but that the sink in the USA is significantly smaller than the inverse models estimates. Because there are different sources of errors at the country level, there is no easy reconciliation of different estimates of carbon fluxes at the global level. Clearly, further work is required to develop data sets for historical land cover change areas and models of biogeochemical changes for an accurate representation of carbon uptake or emissions due to LUC.
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Gani, Md Ataul, Johannes van der Kwast, Michael E. McClain, Gretchen Gettel, and Kenneth Irvine. "Classification of Geomorphic Units and Their Relevance for Nutrient Retention or Export of a Large Lowland Padma River, Bangladesh: A NDVI Based Approach." Remote Sensing 14, no. 6 (March 18, 2022): 1481. http://dx.doi.org/10.3390/rs14061481.
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Geomorphic classification of large rivers identifies morphological patterns, as a foundation for estimating biogeochemical and ecological processes. In order to support the modelling of in-channel nutrient retention or export, the classification of geomorphic units (GUs) was done in the Padma River, Bangladesh, a large and geomorphically-complex lowland river. GUs were classified using the normalized difference vegetation index (NDVI) four times over a year, so as to cover the seasonal variation of water flows. GUs were categorized as primary and secondary channels (C & S); longitudinal bar (L); transverse bar (T); side bar (SB); unvegetated bank (EK); dry channel (ED); island (VI); and water depression (WD). All types of GUs were observed over the four distinct annual seasons, except ED, which was absent during the high flow, monsoon season. Seasonal variation of the surface area of GUs and discharge showed an inverse relation between discharge and exposed surface areas of VI, L, T, and SB. Nutrients mainly enter the river system through water and sediments, and during monsoon, the maximum portion of emergent GUs were submerged. Based on the assumption that nutrient retention is enhanced in the seasonally inundated portions of GUs, nutrient retention-/export-relevant geomorphic units (NREGUs) were identified. Seasonal variation in the area of NREGUs was similar to that of GUs. The mean NDVI values of the main identified NREGUs were different. The variation of NDVI values among seasons in these NREGUs resulted from changes of vegetation cover and type. The variation also occurred due to alteration of the surface area of GUs in different seasons. The changes of vegetation cover indicated by NDVI values across seasons are likely important drivers for biogeochemical and ecological processes.
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Ito, A., J. E. Penner, M. J. Prather, C. P. de Campos, R. A. Houghton, T. Kato, A. K. Jain, et al. "Can we reconcile differences in estimates of carbon fluxes from land-use change and forestry for the 1990s?" Atmospheric Chemistry and Physics 8, no. 12 (June 27, 2008): 3291–310. http://dx.doi.org/10.5194/acp-8-3291-2008.
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Abstract. The effect of Land Use Change and Forestry (LUCF) on terrestrial carbon fluxes can be regarded as a carbon credit or debit under the UNFCCC, but scientific uncertainty in the estimates for LUCF remains large. Here, we assess the LUCF estimates by examining a variety of models of different types with different land cover change maps in the 1990s. Annual carbon pools and their changes are separated into different components for separate geographical regions, while annual land cover change areas and carbon fluxes are disaggregated into different LUCF activities and the biospheric response due to CO2 fertilization and climate change. We developed a consolidated estimate of the terrestrial carbon fluxes that combines book-keeping models with process-based biogeochemical models and inventory estimates and yields an estimate of the global terrestrial carbon flux that is within the uncertainty range developed in the IPCC 4th Assessment Report. We examined the USA and Brazil as case studies in order to assess the cause of differences from the UNFCCC reported carbon fluxes. Major differences in the litter and soil organic matter components are found for the USA. Differences in Brazil result from assumptions about the LUC for agricultural purposes. The effects of CO2 fertilization and climate change also vary significantly in Brazil. Our consolidated estimate shows that the small sink in Latin America is within the uncertainty range from inverse models, but that the sink in the USA is significantly smaller than the inverse models estimates. Because there are different sources of errors at the country level, there is no easy reconciliation of different estimates of carbon fluxes at the global level. Clearly, further work is required to develop data sets for historical land cover change areas and models of biogeochemical changes for an accurate representation of carbon uptake or emissions due to LUC.
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Zhang, Feng Tai, Jun Yi Zhang, and Ji Xin Shao. "Karst Urban Land Use/Cover Change Research - In Guiyang City as an Example." Advanced Materials Research 864-867 (December 2013): 2764–67. http://dx.doi.org/10.4028/www.scientific.net/amr.864-867.2764.
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The urban land use and cover change (LUCC) through the biogeochemical cycle process affecting the city ecological environment, urban district LUCC is the key areas of LUCC research. Guiyang city is the typical karst plateau city of China and even the world, Karst natural background has vulnerability. So under the GIS support ,this article analysis land use/cover change dynamic of the Guiyang city from1990 to 2010, the results show that: (1) Guiyang city construction land area increased by 3.56 times in a short span of 20 years from 57km2 in 1990 to 204 km2 in 2010, urban area times; (2) A large number of woodlands occupied by city urban construction, nearly 20 years takes up the forest land area of 75.8 km2, accounting for 51.56% of the nearly 20 years of new urban construction area;
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Shishkina, Diana Yurievna. "Biogeochemical characteristics of parks and public gardens in Rostov-on-Don." Samara Journal of Science 6, no. 4 (December 1, 2017): 93–98. http://dx.doi.org/10.17816/snv201764119.
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The distribution of heavy metals and arsenic in the soils and leaves of the locust in the parks and squares of Rostov-on-Don was studied. 81 samples of soil and 30 samples of leaves were selected in 13 parks of the city. To determine the concentrations of elements, we used the approximate-quantitative and atomic-absorption analyses. For all elements, the concentration coefficient was calculated, as well as the hazard factor representing the multiplicity of exceeding the MAC or AAC. The total pollution index (Zc), which is the sum of the excess concentrations of individual elements above the background level, was used to characterize complex pollution. When comparing the average concentrations of metals and arsenic with the natural pedogeochemical background, a geochemical association is revealed: Cu2,5Zn2,3Pb1,8V1,3Hg1,3Ni1,2Cd1,2, typical of Rostov-on-Don soils. Weakly local pollution of soils of parks and squares with zinc, copper, vanadium and lead was revealed. The most common pollutant is zinc, for which the highest excess of AAC is characteristic. Pollution of the soil cover of recreational areas is assessed as permissible. With the passage of time, the concentration of zinc decreases and the concentrations of copper and vanadium increase in the soils of park landscapes. There has been increasing biological absorption by the leaves of the locust copper and molybdenum.
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Moskovchenko, Dmitriy V., and Elizaveta A. Romanenko. "Biogeochemical Features of Landscapes of the Nadym Region of YANAO." Bulletin of Nizhnevartovsk State University, no. 4 (December 7, 2022): 122–36. http://dx.doi.org/10.36906/2311-4444/22-4/12.
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The purpose of the study is to reveal the biogeochemical features of soils (illuvial-ferruginous podzols, podzols, cryozems, oligotrophic peat frozen soils, alluvial gray-humus and lacustrine-alluvial soils) and vegetation (Betula nana L., Chamaedaphne calyculata (L.) Moench, Vaccinium uliginosum L., Ledum palustre L., Sphagnum sp L.) of the Nadym region. To achieve the goal, the following tasks were set and implemented: to determine the total content and radial differentiation of elements in the studied soils; to reveal the features of the biological accumulation of elements by the dominant types of vegetation cover. The elemental composition of soils and plants was determined on a serial X-ray fluorescence spectrometer S6 JAGUAR according to the method for determining the mass fraction of metals and metal oxides in powder samples. It has been established that the soils of the Nadym region are characterized by a low content of macroelements, including potassium, calcium, and phosphorus necessary for the mineral nutrition of plants. Calculation of soil-geochemical coefficients shows that the studied soils have an average degree of weathering and leaching moisture regime, peat-gley and cryozems are classified as more fertile soils. Ca, P, and S are accumulated in organic soil horizons, and Co, Cr, and Ni are accumulated in mineral horizons. The radial geochemical structure of cryozems combines features of eluvial-illuvial differentiation and biogenic accumulation. In podzols, the distribution of all elements is eluvial-illuvial, with a minimum in the podzolic horizon. Among plants, the leader in the accumulation of elements is dwarf birch (the maximum accumulation of Ca, K, P, Mg, Zn, Ni), in mosses, on the contrary, the minimum accumulation of elements was found. The elements of energetic and strong accumulation (Kb=n-100n) include Pb, Mo, Cd, Cl, S.
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Deng, J., C. Li, S. Frolking, Y. Zhang, K. Bäckstrand, and P. Crill. "Assessing effects of permafrost thaw on C fluxes based on multiyear modeling across a permafrost thaw gradient at Stordalen, Sweden." Biogeosciences 11, no. 17 (September 9, 2014): 4753–70. http://dx.doi.org/10.5194/bg-11-4753-2014.
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Abstract. Northern peatlands in permafrost regions contain a large amount of organic carbon (C) in the soil. Climate warming and associated permafrost degradation are expected to have significant impacts on the C balance of these ecosystems, but the magnitude is uncertain. We incorporated a permafrost model, Northern Ecosystem Soil Temperature (NEST), into a biogeochemical model, DeNitrification-DeComposition (DNDC), to model C dynamics in high-latitude peatland ecosystems. The enhanced model was applied to assess effects of permafrost thaw on C fluxes of a subarctic peatland at Stordalen, Sweden. DNDC simulated soil freeze–thaw dynamics, net ecosystem exchange of CO2 (NEE), and CH4 fluxes across three typical land cover types, which represent a gradient in the process of ongoing permafrost thaw at Stordalen. Model results were compared with multiyear field measurements, and the validation indicates that DNDC was able to simulate observed differences in seasonal soil thaw, NEE, and CH4 fluxes across the three land cover types. Consistent with the results from field studies, the modeled C fluxes across the permafrost thaw gradient demonstrate that permafrost thaw and the associated changes in soil hydrology and vegetation not only increase net uptake of C from the atmosphere but also increase the annual to decadal radiative forcing impacts on climate due to increased CH4 emissions. This study indicates the potential of utilizing biogeochemical models, such as DNDC, to predict the soil thermal regime in permafrost areas and to investigate impacts of permafrost thaw on ecosystem C fluxes after incorporating a permafrost component into the model framework.
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Deng, J., C. Li, S. Frolking, Y. Zhang, K. Bäckstrand, and P. Crill. "Assessing effects of permafrost thaw on C fluxes based on a multi-year modeling across a permafrost thaw gradient at Stordalen, Sweden." Biogeosciences Discussions 11, no. 3 (March 11, 2014): 3963–99. http://dx.doi.org/10.5194/bgd-11-3963-2014.
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Abstract. Northern peatlands in permafrost regions contain large amount of organic carbon (C) in the soil. Climate warming and associated permafrost degradation are expected to have significant impacts on the C balance of these ecosystems, but the magnitude is uncertain. We incorporated a permafrost model, Northern Ecosystem Soil Temperature (NEST), into a biogeochemical model, DeNitrification-DeComposition (DNDC), to model C dynamics in high-latitude peatland ecosystems. The enhanced model was applied to assess effects of permafrost thaw on C fluxes of a sub-arctic peatland at Stordalen, Sweden. DNDC simulated soil freeze/thaw dynamics, net ecosystem exchange of CO2 (NEE), and CH4 fluxes across three typical land cover types, which represent different stages in the process of ongoing permafrost thaw at Stordalen. Model results were compared with multi-year field measurements and the validation indicates that DNDC was able to simulate observed differences in soil thaw, NEE, and CH4 fluxes across the three land cover types at Stordalen. Consistent with the results from field studies, the modeled C fluxes across the permafrost thaw gradient demonstrate that permafrost thaw and the associated changes in soil hydrology and vegetation increase net uptake of C from the atmosphere, but also increase the radiative forcing impacts on climate due to increased CH4 emissions. This study indicates the potential of utilizing biogeochemical models, such as DNDC, to predict soil thermal regime in permafrost areas and to investigate impacts of permafrost thaw on ecosystem C fluxes after incorporating a permafrost component into the model framework.
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Bondarevich, E. A., N. N. Kotsyurzhinskaya, A. A. Voychenko, T. Yu Voychenko, O. A. Leskova, and A. P. Leskov. "THE STATE OF THE SOIL COVER IN THE AREAS OF TECHNOGENIC BIOGEOCHEMICAL ANOMALIES IN TRANSBAIKAL REGION." Успехи современного естествознания (Advances in Current Natural Sciences), no. 3 2020 (2020): 57–64. http://dx.doi.org/10.17513/use.37346.
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Liu, Jinxun, Shuguang Liu, Thomas R. Loveland, and Larry L. Tieszen. "Integrating remotely sensed land cover observations and a biogeochemical model for estimating forest ecosystem carbon dynamics." Ecological Modelling 219, no. 3-4 (December 2008): 361–72. http://dx.doi.org/10.1016/j.ecolmodel.2008.04.019.
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Domingo, F., J. Puigdefabregas, M. J. Moro, and J. Bellot. "Role of vegetation cover in the biogeochemical balances of a small afforested catchment in southeastern Spain." Journal of Hydrology 159, no. 1-4 (July 1994): 275–89. http://dx.doi.org/10.1016/0022-1694(94)90261-5.
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Palafox-Juárez, Erika Betzabeth, Jorge Omar López-Martínez, José Luis Hernández-Stefanoni, and Héctor Hernández-Nuñez. "Impact of Urban Land-Cover Changes on the Spatial-Temporal Land Surface Temperature in a Tropical City of Mexico." ISPRS International Journal of Geo-Information 10, no. 2 (February 13, 2021): 76. http://dx.doi.org/10.3390/ijgi10020076.
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Climate change has severe consequences on ecosystem processes, as well as on people’s quality of life. It has been suggested that the loss of vegetation cover increases the land surface temperature (LST) due to modifications in biogeochemical patterns, generating a phenomenon known as “urban heat island” (UHI). The aim of this work was to analyze the effects of urban land-cover changes on the spatiotemporal variation of surface temperature in the tropical city of Mérida, Mexico. To find these effects we used both detected land-cover changes as well as variations of the Normalized Difference Vegetation Index (NDVI). Mérida is ranked worldwide as one of the best cities to live due to its quality of life. Data from satellite images of Landsat were analyzed to calculate land use change (LUC), LST, and NDVI. LST increased ca. 4 °C in the dry season and 3 °C in the wet season because of the LUC. In addition, a positive relationship between the LST and the NDVI was observed mainly in the dry season. The results confirm an increase in the LST as a consequence of the loss of vegetation cover, which favors the urban heat island phenomenon.
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Al-Taisan, Wafa’a A. "A Remote Sensing Approach for Displaying the Changes in the Vegetation Cover at Az Zakhnuniyah Island at Arabian Gulf, Saudi Arabia." Scientifica 2022 (March 17, 2022): 1–14. http://dx.doi.org/10.1155/2022/2907921.
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In the terrestrial ecosystem, vegetation is the important component of exchanging of water and energy in biogeochemical and climate cycle. A study was conducted to detect the vegetation cover change at Az Zakhnuniyah island by using remote sensing techniques. It includes vegetation analysis using normalized difference vegetation index (NDVI) while comparing with climatological data including temperature, humidity, and precipitation. A clear trend was seen in climatological parameters where temperature and humidity were rising decade by decade although NDVI did not show. In addition, increasing soil salinization over the years was observed when soil salinity index was used. NDVI-based long-term decadal analysis on vegetation cover based on Landsat surface reflectance data showed increase of vegetation cover which was also linked to precipitation trends. Also, the short-term demi-decadal comparison using PROBA-V showed the vegetation cover reduction between 2015 and 2019. Nevertheless, the sea level surrounding the island also showed an increasing trend of 0.34 cm/y, which could be the cause of inundation in some parts of the island in future. Furthermore, all these trends need to be observed in entirety as many of those trends can be interlinked.
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Patakamuria, S. K., S. Agrawal, and M. Krishnaveni. "Time-Series analysis of MODIS NDVI data along with ancillary data for Land use/Land cover mapping of Uttarakhand." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-8 (December 23, 2014): 1491–500. http://dx.doi.org/10.5194/isprsarchives-xl-8-1491-2014.
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Land use and land cover plays an important role in biogeochemical cycles, global climate and seasonal changes. Mapping land use and land cover at various spatial and temporal scales is thus required. Reliable and up to date land use/land cover data is of prime importance for Uttarakhand, which houses twelve national parks and wildlife sanctuaries and also has a vast potential in tourism sector. The research is aimed at mapping the land use/land cover for Uttarakhand state of India using Moderate Resolution Imaging Spectroradiometer (MODIS) data for the year 2010. The study also incorporated smoothening of time-series plots using filtering techniques, which helped in identifying phenological characteristics of various land cover types. Multi temporal Normalized Difference Vegetation Index (NDVI) data for the year 2010 was used for mapping the Land use/land cover at 250m coarse resolution. A total of 23 images covering a single year were layer stacked and 150 clusters were generated using unsupervised classification (ISODATA) on the yearly composite. To identify different types of land cover classes, the temporal pattern (or) phenological information observed from the MODIS (MOD13Q1) NDVI, elevation data from Shuttle Radar Topography Mission (SRTM), MODIS water mask (MOD44W), Nighttime Lights Time Series data from Defense Meteorological Satellite Program (DMSP) and Indian Remote Sensing (IRS) Advanced Wide Field Sensor (AWiFS) data were used. Final map product is generated by adopting hybrid classification approach, which resulted in detailed and accurate land use and land cover map.
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Meier, H. E. Markus, Christian Dieterich, Matthias Gröger, Cyril Dutheil, Florian Börgel, Kseniia Safonova, Ole B. Christensen, and Erik Kjellström. "Oceanographic regional climate projections for the Baltic Sea until 2100." Earth System Dynamics 13, no. 1 (January 25, 2022): 159–99. http://dx.doi.org/10.5194/esd-13-159-2022.
Full textAbstract:
Abstract. The Baltic Sea, located in northern Europe, is a semi-enclosed, shallow and tideless sea with seasonal sea-ice cover in its northern sub-basins. Its long water residence time contributes to oxygen depletion in the bottom water of its southern sub-basins. In this study, recently performed scenario simulations for the Baltic Sea including marine biogeochemistry were analysed and compared with earlier published projections. Specifically, dynamical downscaling using a regionally coupled atmosphere–ocean climate model was used to regionalise four global Earth system models. However, as the regional climate model does not include components representing terrestrial and marine biogeochemistry, an additional catchment and a coupled physical–biogeochemical model for the Baltic Sea were included. The scenario simulations take the impact of various global sea level rise scenarios into account. According to the projections, compared to the present climate, higher water temperatures, a shallower mixed layer with a sharper thermocline during summer, less sea-ice cover and greater mixing in the northern Baltic Sea during winter can be expected. Both the frequency and the duration of marine heat waves will increase significantly, in particular in the coastal zone of the southern Baltic Sea (except in regions with frequent upwellings). Nonetheless, due to the uncertainties in the projections regarding regional winds, the water cycle and the global sea level rise, robust and statistically significant salinity changes could not be identified. The impact of a changing climate on biogeochemical cycling is predicted to be considerable but still smaller than that of plausible nutrient input changes. Implementing the proposed Baltic Sea Action Plan, a nutrient input abatement plan for the entire catchment area, would result in a significantly improved ecological status of the Baltic Sea, including reductions in the size of the hypoxic area also in a future climate, which in turn would increase the resilience of the Baltic Sea against anticipated climate change. While our findings regarding changes in heat-cycle variables mainly confirm earlier scenario simulations, they differ substantially from earlier projections of salinity and biogeochemical cycles, due to differences in experimental setups and in input scenarios for bioavailable nutrients.
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Lawrence, Peter J., Johannes J. Feddema, Gordon B. Bonan, Gerald A. Meehl, Brian C. O’Neill, Keith W. Oleson, Samuel Levis, et al. "Simulating the Biogeochemical and Biogeophysical Impacts of Transient Land Cover Change and Wood Harvest in the Community Climate System Model (CCSM4) from 1850 to 2100." Journal of Climate 25, no. 9 (May 2012): 3071–95. http://dx.doi.org/10.1175/jcli-d-11-00256.1.
Full textAbstract:
To assess the climate impacts of historical and projected land cover change in the Community Climate System Model, version 4 (CCSM4), new time series of transient Community Land Model, version 4 (CLM4) plant functional type (PFT) and wood harvest parameters have been developed. The new parameters capture the dynamics of the Coupled Model Intercomparison Project phase 5 (CMIP5) land cover change and wood harvest trajectories for the historical period from 1850 to 2005 and for the four representative concentration pathway (RCP) scenarios from 2006 to 2100. Analysis of the biogeochemical impacts of land cover change in CCSM4 reveals that the model produced a historical cumulative land use flux of 127.7 PgC from 1850 to 2005, which is in general agreement with other global estimates of 156 PgC for the same period. The biogeophysical impacts of the transient land cover change parameters were cooling of the near-surface atmosphere over land by −0.1°C, through increased surface albedo and reduced shortwave radiation absorption. When combined with other transient climate forcings, the higher albedo from land cover change was counteracted by decreasing snow albedo from black carbon deposition and high-latitude warming. The future CCSM4 RCP simulations showed that the CLM4 transient PFT parameters can be used to represent a wide range of land cover change scenarios. In the reforestation scenario of RCP 4.5, CCSM4 simulated a drawdown of 67.3 PgC from the atmosphere into the terrestrial ecosystem and product pools. By contrast the RCP 8.5 scenario with deforestation and high wood harvest resulted in the release of 30.3 PgC currently stored in the ecosystem.
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Chernov, Ilya, and Alexey Tolstikov. "The White Sea: Available Data and Numerical Models." Geosciences 10, no. 11 (November 16, 2020): 463. http://dx.doi.org/10.3390/geosciences10110463.
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The White Sea is a small shallow semi-closed sea in the North-West of Russia. It is strongly affected by induced tides, so the tidal motion dominates in the sea. Sea ice is seasonal and the water salinity is less than in the neighbouring Barents sea due to strong river discharge. We review the sources of in-situ and satellite data that are available for the sea, and describe those few numerical models, together with the challenges that are faced. We focus on the large-scale circulation and thermohaline fields, but also cover sea ice, river runoff, and pelagic biogeochemical data.