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Roland W Scholz - One of the best experts on this subject based on the ideXlab platform.
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losses and use efficiencies along the Phosphorus Cycle part 2 understanding the concept of efficiency
Resources Conservation and Recycling, 2015Co-Authors: Roland W Scholz, Friedrichwilhelm WellmerAbstract:Part 1 of this paper showed that losses and efficiencies are highly similar concepts used to valuate the quality of a production process from an input–output economics perspective. Both concepts are useful in methods that aim to reduce the amount of input (money, material, labor, etc.) needed to get a certain desired output. Yet, from a decision-theoretic perspective, both concepts are secondary. They are subordinate to the desired goal, product, or service, i.e., the efficacy, and the overall impacts on a tangible system, i.e., effectiveness (which we consider as an overall utility) and are of superior importance to an action or a decision. Part 2 provides an in-depth discussion of efficiency. We show that we need an overall objective (a kind of total utility), such as effectiveness or resilience, as a target variable for sustainable resource use. Efficiency is a valuation function that assesses how much we have to invest in order to receive a certain quantity and/or quality of a desired outcome or product. We conceive of effectiveness as the capability of an action, decision, or technology to attain a meaningful and satisfying overall result (with respect to a specific perspective/interest or overall objective). We further shed light on several misperceived relationships between efficacy and efficiency. Both material/technical and economic efficiency can be defined as a fraction of two variables, i.e., the ratio between input and output. Here, the nominator (i.e., the output) is usually what we consider as efficacy. For the agro-use of P (and many organismic systems), the material-biophysical output is not linearly related to the input, but we are facing the Law of Marginal Diminishing Returns (which contrasts with the Tayloristic idea that increasing throughput increases efficiency). Thus, unrealistic expectations and misperceptions may emerge. We exemplarily discuss and substantiate by theoretical and data-based arguments why the objective to “increase global P nutrient use efficiency by 30% and the outcome of yield by 30%” is not possible in the next decades as the antagonistic relationship between efficacy and efficiency and the diverging options in different countries and world regions are ignored. Finally, we briefly illuminate in what way the evaluation of Phosphorus management may be considered sustainable and what rebound effects may be mastered. This is done by discussing system boundaries, evaluation perspectives, and the factors discussed in the context of efficacy, efficiency, and effectiveness.
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losses and use efficiencies along the Phosphorus Cycle part 1 dilemmata and losses in the mines and other nodes of the supply chain
Resources Conservation and Recycling, 2015Co-Authors: Roland W Scholz, Friedrichwilhelm WellmerAbstract:This contribution provides a set of definitions and relates the concepts of losses, efficiencies, efficacy, and effectiveness (which is conceived as a kind of overall utility) in general and for the case of Phosphorus. We show how the material—technical and economic value-related definitions are linked and can be utilized for sustainable Phosphorus and resource management. Part 1 provides an overview of global anthropogenic and natural Phosphorus flows and identifies major losses from the current Phosphorus supply–demand chain. We discuss in what way the concepts of efficacy, efficiency, and effectiveness are related and how they may be used for assessing aspects of sustainable management. We discuss losses in mining and consider how management of the mining rate, cut-off grade, and stripping ratio might affect losses today and in the future. Although we identify critical losses of the supply–demand chain, the back sections of the paper focuses on losses in mining and beneficiation. When introducing different types of losses, we illuminate whether the residues in mining should be perceived as losses and whether mining companies can increase the total resource efficiency by decreasing the cut-off grade (i.e., by decreasing the concentration of phosphate ore that becomes subject to mining and beneficiation). This is discussed from an intergenerational justice and external costs perspective of losses. We introduce a classification system for (i) highly probable or definite absolute losses, (ii) losses from the supply–demand chain that become deferred losses, and (iii) uncertain losses that may become subject to sustainable resource management. This classification may be applied to all nodes of the supply–demand chain. We elaborate on how these types of losses can become subject to sustainable resource management. Part 2 of the paper discusses various operationalizations, fallacies, and challenges related to applying different efficiency terms.
Karl B Follmi - One of the best experts on this subject based on the ideXlab platform.
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Phosphorus Cycle disturbances during the late devonian anoxic events
Global and Planetary Change, 2020Co-Authors: Lawrence Percival, Michal Rakocinski, David P G Bond, Leszek Marynowski, Ashleigh V S Hood, Thierry Adatte, Jorge E Spangenberg, Karl B FollmiAbstract:Abstract The Late Devonian was marked by repeated faunal crises and episodes of geographically widespread marine anoxia, and featured one of the ‘Big Five’ mass extinctions of the Phanerozoic Aeon during the Frasnian–Famennian transition. However, the processes responsible for causing the numerous anoxic events remain unclear. This study highlights the occurrence of disturbances to the Phosphorus Cycle during several Late Devonian crises by investigating sedimentary concentrations of the element (Ptot) as a tracer of nutrient influx, as well as its ratio with total organic carbon (TOC) to infer the recycling of the element from marine sediments. Increased TOC/Ptot ratios in the Frasnian–Famennian Lower and Upper Kellwasser horizons and upper Famennian Annulata and Hangenberg levels suggest that such nutrient recycling occurred across extensive areas of the marine shelf in Laurentia and both Rheic Ocean margins at those times, helping to sustain reducing conditions in those environments. Elevated Ptot values in the Upper Kellwasser, Annulata, and Hangenberg levels are consistent with an enhanced nutrient influx as the initial trigger for the anoxia. Correlation of Phosphorus trends with other geochemical indicators of weathering/detrital influx (osmium-isotope, silicon/aluminum, and titanium/aluminium ratios) support a scenario in which terrestrial runoff provided these nutrients both to marine shelves and the oceanic inventory. Upwelling of oceanic deep-water bodies may have then brought the Phosphorus to areas that had not featured major direct inputs of terrigenous material. The exception is the Lower Kellwasser Event, during which there was no increase in Phosphorus delivery to marine areas and no evidence for terrestrial influx at the studied sections, invoking a different mechanism for the development of water-column anoxia. Clearly, the Late Devonian marine realm was unusually susceptible to becoming anoxic through various possible triggers, including nutrient influx from land and/or deep-water upwelling, and the recycling of Phosphorus from newly deposited sediments.
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the Phosphorus Cycle phosphogenesis and marine phosphate rich deposits
Earth-Science Reviews, 1996Co-Authors: Karl B FollmiAbstract:Abstract Phosphorus (in the form of phosphate) is an essential nutrient and energy carrier on many different levels of life, and a key element in mediating between living and lifeless parts of the biosphere. One of the most important aspects of the Phosphorus Cycle is its vital role in governing productivity, thereby interacting with the exogenic part of the carbon Cycle, which, in turn, is important in regulating Earth's climate. Phosphorus is a prime element to be traced in Earth's history, because it allows for the reconstruction of long-term feedback mechanisms between climate, environment and ecology, and of global change as such. Marine sedimentary phosphate deposits are particularly suited to study aspects of the Phosphorus Cycle, because, in the case of ubiquity, their origin may result from a general acceleration of the global Phosphorus Cycle. Sources of sedimentary phosphate are microbial breakdown of buried organic matter and redox-driven phosphate desorption from iron and manganese oxyhydroxides. Dissolved sea-water phosphate represents an additional source which may become important in the formation of phosphatic hardgrounds. The main locus of phosphogenesis is near the sediment-water interface, but phosphogenesis also occurs at greater sediment depths. Current-induced winnowing and transport processes along the sea floor concentrate phosphate precipitates into deposits, which exhibit internal stratification patterns typical for the prevailing hydraulic energy regime. In a sequence-stratigraphic context, phosphate deposits preferentially occur along marine or maximum flooding surfaces. Consequent sedimentary reworking may result in the transfer of phosphates to highstand or lowstand deposits. (Bio-)chemical weathering on continents represents the most significant source of bioavailable Phosphorus. This implies that long-term changes in marine Phosphorus levels — and with these changes in marine ecology, productivity rates and ratios of exported carbonate carbon and organic carbon — are a response to changes in continental weathering rates. A compilation of marine sedimentary Phosphorus burial rates for the last 160 Myr suggests that natural variations have occurred that span one order of magnitude. For the late Jurassic, Cretaceous and most of the Paleogene, the Phosphorus Cycle appears to have been accelerated in times of climate warming, which was most likely due to the spreading of zones of humid climate and more intense continental weathering. In the Neogene, the Phosphorus Cycle appears to have responded to changes in glacially induced weathering. This suggests that uniform interpretations with respect to the emplacement of major phosphorite deposits should be treated with caution. Integrated analyses of the sedimentary and biogeochemical context of phosphorite occurrences may help to identify paleoenvironmental conditions, as well as to improve our understanding of periods of enhanced phosphate accumulation, periods which were usually characterized by steep gradients in the development of climate and environment. With regard to the complexity of feedback mechanisms between the Phosphorus Cycle and the biosphere, the present-day input rates of phosphate into the world's oceans should be of great concern. They are more than doubled by anthropogenic means and affect ecological systems on a rapidly increasing scale.
Gabriel M. Filippelli - One of the best experts on this subject based on the ideXlab platform.
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The global Phosphorus Cycle: Past, present, and future
Elements, 2008Co-Authors: Gabriel M. FilippelliAbstract:The cycling of Phosphorus, a biocritical element in short supply in nature, is an important Earth system process. Variations in the Phosphorus Cycle have occurred in the past. For example, the rapid uplift of the Himalayan-Tibet Plateau increased chemical weathering, which led to enhanced input of Phosphorus to the oceans. This drove the late Miocene "biogenic bloom." Additionally, Phosphorus is redistributed on glacial timescales, resulting from the loss of the substantial continental margin sink for reactive P during glacial sea-level lowstands. The modern terrestrial Phosphorus Cycle is dominated by agriculture and human activity. The natural riverine load of Phosphorus has doubled due to increased use of fertilizers, deforestation and soil loss, and sewage sources. This has led to eutrophication of lakes and coastal areas, and will continue to have an impact for several thousand years based on forward modeling of human activities.
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the global Phosphorus Cycle
Reviews in Mineralogy & Geochemistry, 2002Co-Authors: Gabriel M. FilippelliAbstract:Phosphorus (P) is a limiting nutrient for terrestrial biological productivity that commonly plays a key role in net carbon uptake in terrestrial ecosystems (Tiessen et al. 1984, Roberts et al. 1985, Lajtha and Schlesinger 1988). Unlike nitrogen (another limiting nutrient but one with an abundant atmospheric pool), the availability of “new” P in ecosystems is restricted by the rate of release of this element during soil weathering. Because of the limitations of P availability, P is generally reCycled to various extents in ecosystems depending on climate, soil type, and ecosystem level. The release of P from apatite dissolution is a key control on ecosystem productivity (Cole et al. 1977, Tiessen et al. 1984, Roberts et al. 1985, Crews et al. 1995, Vitousek et al. 1997, Schlesinger et al. 1998), which in turn is critical to terrestrial carbon balances (e.g., Kump and Alley 1994, Adams 1995). Furthermore, the weathering of P from the terrestrial system and transport by rivers is the only appreciable source of P to the oceans. On longer time scales, this supply of P also limits the total amount of primary production in the ocean (Holland 1978, Broecker 1982, Smith 1984, Filippelli and Delaney 1994). Thus, understanding the controls on P weathering from land and transport to the ocean is important for models of global change. In this paper, I will present an overview of the natural (pre-human) and modern (syn-human) global P mass balances, followed by in-depth examinations of several current areas of research in P cycling, including climatic controls on ecosystem dynamics and soil development, the control of oxygen on coupled P and Carbon (C) cycling in continental margins, and the role that P plays in controlling ocean productivity on Cenozoic timescales. ### Natural (pre-human) Phosphorus Cycle The human impact …
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variations in the global Phosphorus Cycle
In: Glenn CR and Prévôt-Lucas L and Lucas J and Geology SEPMSFS (eds.) Marine authigenesis: from global to microbial. (pp. 21-33). SEPM (Society for S, 2000Co-Authors: John S Compton, Gabriel M. Filippelli, David J Mallinson, Craig R Glenn, K Follmi, Graham A Shields, Y ZaninAbstract:Phosphorus is a critical element in the biosphere, limiting biological productivity and thus modulating the global carbon Cycle and climate. Fluxes of the global Phosphorus Cycle remain poorly constrained. The prehuman reactive Phosphorus flux to the ocean is estimated to range from 0.7—4.8 x 1012g/yr. Uncertainty in the reactive Phosphorus flux hinges primarily on the uncertain fate of phosphate adsorbed to iron oxyhydroxide particles which are estimated to constitute 50% or more of the chemically weathered-Phosphorus river flux. Most reactive Phosphorus is initially removed from seawater by burial of organic matter and by scavenging onto iron–manganese oxide particles derived from mid-ocean ridge (MOR) hydrothermal activity. Calculation of the oceanic Phosphorus burial flux is complicated by early diagenetic redistribution of both oceanic and terrestrial Phosphorus. Increased Phosphorus input during periods of warm, humid climate is offset to some degree by increased burial rate as productivity shifts to expanded shallow-water estuary and shelf areas where Phosphorus is rapidly decoupled from organic matter to form phosphorite. Phosphorus scavenging is greater if high sea levels are associated with increased MOR hydrothermal activity such as during the Late Cretaceous. Less Phosphorus is derived from weathering during cool, dry climatic periods but a more direct transportation of Phosphorus to the deep ocean, and a shift of productive upwelling regions to deeper water areas allows more Phosphorus to be reCycled in the water column. Lowered sea level results in less effective trapping of Phosphorus in constricted estuary and shelf areas and in an increase in the Phosphorus flux to the deep ocean from sediment resuspension. A decrease in MOR spreading rates and the resulting decrease in Phosphorus scavenging by iron–manganese oxide particles would result in more Phosphorus for the biosphere. Orogeny and glaciation may accelerate chemical weathering of Phosphorus from the continents when the increased particle flux is exposed to warm and humid climate. Large, reworked phosphorite deposits may proxy for short-term organic carbon burial and correspond to periods of increased reactive Phosphorus input that cannot be accommodated by longterm organic matter an
Elena M Bennett - One of the best experts on this subject based on the ideXlab platform.
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The Influence of Agricultural Trade and Livestock Production on the Global Phosphorus Cycle
Ecosystems, 2012Co-Authors: Meagan E. Schipanski, Elena M BennettAbstract:Trends of increasing agricultural trade, increased concentration of livestock production systems, and increased human consumption of livestock products influence the distribution of nutrients across the global landscape. Phosphorus (P) represents a unique management challenge as we are rapidly depleting mineable reserves of this essential and non-renewable resource. At the same time, its overuse can lead to pollution of aquatic ecosystems. We analyzed the relative contributions of food crop, feed crop, and livestock product trade to P flows through agricultural soils for 12 countries from 1961 to 2007. Due to the intensification of agricultural production, average soil surface P balances more than tripled from 6 to 21 kg P ha^−1 between 1961 and 2007 for the 12 study countries. Consequently, countries that are primarily agricultural exporters carried increased risks for water pollution or, for Argentina, reduced soil fertility due to soil P mining to support exports. In 2007, nations imported food and feed from regions with higher apparent P fertilizer use efficiencies than if those crops were produced domestically. However, this was largely because imports were sourced from regions depleting soil P resources to support export crop production. In addition, the pattern of regional specialization and intensification of production systems also reduced the potential to reCycle P resources, with greater implications for livestock production than crop production. In a globalizing world, it will be increasingly important to integrate biophysical constraints of our natural resources and environmental impacts of agricultural systems into trade policy and agreements and to develop mechanisms that move us closer to more equitable management of non-renewable resources such as Phosphorus.
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Phosphorus Cycle a broken biogeochemical Cycle
Nature, 2011Co-Authors: James J Elser, Elena M BennettAbstract:Excess Phosphorus is polluting our environment while, ironically, mineable resources of this essential nutrient are limited. James Elser and Elena Bennett argue that recycling programmes are urgently needed.
Binbin J Pearce - One of the best experts on this subject based on the ideXlab platform.
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Phosphorus recovery transition tool prtt a transdisciplinary framework for implementing a regenerative urban Phosphorus Cycle
Journal of Cleaner Production, 2015Co-Authors: Binbin J PearceAbstract:Abstract The anthropogenic use of Phosphorus has emerged as a one of the major drivers of global environmental change. The finite supply of the nutrient, geographical concentration of the remaining supply, and continuing occurrences of eutrophication and harmful algal blooms (caused, in part, by excessive Phosphorus outflows into the environment) are causes for immediate concern. As a response, there is increasing recognition that Phosphorus entering waste streams should be recovered as a resource rather than disposed of as a pollutant. While Phosphorus recovery technology and strategies have been outlined in some detail in the existing literature, none have explicitly addressed the reasons for why these processes have not been implemented at scale. In addition, the potential for urban systems to play a role in creating a holistic management system for Phosphorus has received little recognition. This paper addresses these knowledge gaps by offering a tool for analyzing the context, drivers, barriers, and implementation of Phosphorus recovery technologies in urban areas. The framework tool consists of five guiding questions. The process of answering the questions presents an opportunity for researchers, decision makers, and community stakeholders to explicitly identify what and how changes to the current system can be made. This paper provides an approach for producing the knowledge necessary for facilitating the transition to an urban Phosphorus recovery regime that is relevant for both practitioners and academics. The approach may also be adapted to understanding other resource Cycles in the future, such as nitrogen, water, and energy.