Freshwater eutrophication: spatially explicit fate factors for nitrogen and phosphorus emissions at the global scale

2021 ◽  
Vol 26 (2) ◽  
pp. 388-401
Author(s):  
Sandra Payen ◽  
Nuno Cosme ◽  
Alexander H. Elliott
2010 ◽  
Vol 14 (2) ◽  
pp. 1-22 ◽  
Author(s):  
Philip Potter ◽  
Navin Ramankutty ◽  
Elena M. Bennett ◽  
Simon D. Donner

Abstract Agriculture has had a tremendous impact on soil nutrients around the world. In some regions, soil nutrients are depleted because of low initial soil fertility or excessive nutrient removals through intense land use relative to nutrient additions. In other regions, application of chemical fertilizers and manure has led to an accumulation of nutrients and subsequent water quality problems. Understanding the current level and spatial patterns of fertilizer and manure inputs would greatly improve the ability to identify areas that might be sensitive to aquatic eutrophication or to nutrient depletion. The authors calculated spatially explicit fertilizer inputs of nitrogen (N) and phosphorus (P) by fusing national-level statistics on fertilizer use with global maps of harvested area for 175 crops. They also calculated spatially explicit manure inputs of N and P by fusing global maps of animal density and international data on manure production and nutrient content. Significantly higher application rates were found for both fertilizers and manures in the Northern Hemisphere, with maxima centered on areas with intensive cropland and high densities of livestock. Furthermore, nutrient use is confined to a few major hot spots, with approximately 10% of the treated land receiving over 50% of the use of both fertilizers and manures. The authors’ new spatial disaggregation of the rich International Fertilizer Industry Association (IFA) fertilizer-use dataset will provide new and interesting avenues to explore the impact of anthropogenic activity on ecosystems at the global scale and may also have implications for policies designed to improve soil quality or reduce nutrient runoff.


2016 ◽  
Author(s):  
Daniel Moran ◽  
Keiichiro Kanemoto

Summary SentenceSpatially explicit footprints make it possible to locate biodiversity hotspots linked to global supply chains.Identifying species threat hotspots has been a successful approach for setting conservation priorities. One major challenge in conservation is that in many hotspots export industries continue to drive overexploitation. Conservation measures must consider not just the point of impact, but also the consumer demand that ultimately drives resource use. To understand which species threat hotspots are driven by which consumers, we have developed a new approach to link a set of biodiversity footprint accounts to the hotspots of threatened species on the IUCN Red List. The result is a map connecting global supply chains to impact locations. Connecting consumption to spatially explicit hotspots driven by production has not been done before on a global scale. Locating biodiversity threat hotspots driven by consumption of goods and services can help connect conservationists, consumers, companies, and governments in order to better target conservation actions.


2020 ◽  
Author(s):  
Wei Zhi ◽  
Yuning Shi ◽  
Hang Wen ◽  
Leila Saberi ◽  
Gene-Hua Crystal Ng ◽  
...  

Abstract. Watersheds are the fundamental Earth surface functioning unit that connects the land to aquatic systems. Existing watershed-scale models typically have physics-based representation of hydrology process but often lack mechanism-based, multi-component representation of reaction thermodynamics and kinetics. This lack of watershed reactive transport models has limited our ability to understand and predict solute export and water quality, particularly under changing climate and anthropogenic conditions. Here we present a recently developed BioRT-Flux-PIHM (BFP) v1.0, a watershed-scale biogeochemical reactive transport model. Augmenting the previously developed RT-Flux-PIHM that integrates land-surface interactions, surface hydrology, and abiotic geochemical reactions (Bao et al., 2017, WRR), the new development enables the simulation of 1) biotic processes including plant uptake and microbe-mediated biogeochemical reactions that are relevant to the transformation of organic matter that involve carbon, nitrogen, and phosphorus; and 2) shallow and deep water partitioning to represent surface and groundwater interactions. 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 to understand reactive transport processes in multiple watersheds across different climate, vegetation, and geology conditions. This paper introduces the governing equations and model structure of the code. It also demonstrates examples that simulate shallow and deep water interactions, and biogeochemical reactive transport relevant to nitrate and dissolved organic carbon (DOC). These examples were illustrated in two simulation modes of varying complexity. One is the spatially implicit mode that focuses on processes and average behavior of a watershed. Another is in a spatially explicit mode that includes details of topography, land cover, and soil property conditions. The spatially explicit mode can be used to understand the impacts of spatial structure and identify hot spots of biogeochemical reactions.


Author(s):  
Andrea Fra-Vázquez ◽  
Daniel Valenzuela-Heredia

The study of biogeochemical cycles is important to understand the circulation of elements through aquatic, aerial and terrestrial ecosystems. Among others, N and P are considered as the limiting nutrients that determine the productivity of organisms. Since human activity is increasing its influence over these cycles at a global scale, it is important to analyze the implications of anthropogenic variations in order to detect the sources and try to prevent or reduce their impact. Moreover, not only the increasing or diminished concentration of nitrogen and phosphorus in nature by human resource exploitations is needed to account today. As metals play a crucial role in the dynamics of these essential elements, their presence in the environment also requires a significant attention.


2020 ◽  
Author(s):  
Isabel Meza ◽  
Stefan Siebert ◽  
Petra Döll ◽  
Jürgen Kusche ◽  
Claudia Herbert ◽  
...  

<p>Drought is a recurrent global phenomenon considered one of the most complex hazards with manifold impacts on communities, ecosystems, and economies. While many sectors are affected by drought, agriculture’s high dependency on water makes it particularly susceptible to droughts, threatening the livelihoods of many, and hampering the achievement of the Sustainable Development Goals. Identifying pathways towards more drought resilient societies by analyzing the drivers and spatial patterns of drought risk is of increasing importance for the identification, prioritization and planning of risk reduction, risk transfer and adaptation options. While major progress has been made regarding the mapping, prediction and monitoring of drought events at different spatial scales (local to global), comprehensive drought risk assessments that consider the complex interaction of drought hazards, exposure and vulnerability factors are still the exception.</p><p>Here, we present, for the first time, a global-scale drought risk assessment at national level for both irrigated and rain-fed agricultural systems. The analysis integrates (1) composite drought hazard indicators based on historical climate conditions (1980-2016), (2) exposure data represented by the harvest area of irrigated and rainfed systems, and (3) an expert-weighted set of social-ecological vulnerability indicators. The latter were identified through a systematic review of literature (n = 105 peer-reviewed articles) and expert consultations (n = 78 experts). This study attempted to characterize the average drought risk for the whole study period.</p><p>Results show that drought risk of rain-fed and irrigated agricultural systems display different heterogeneous patterns at the global level with higher risk for southeastern Europe, as well as northern and southern Africa. The vulnerability to drought highlights the relevance to increase the countries’ coping capacity in order to reduce their overall drought risk. For instance, the United States, which despite being highly exposed to drought hazard, has low socio-ecological susceptibility and sufficiently high coping capacities to reduce the overall drought risk considerably. When comparing irrigated and rain-fed drought hazard/exposure, there are significant regional differences. For example, the northern part  of Central Africa and South America have low hazard/exposure levels of irrigated crops, resulting in a low total risk, although high vulnerability characterize these regions. South Africa, however, has a high amount of rain-fed crops exposed to drought, but a lower vulnerability compared to other African countries. Further, the drivers of drought risk vary substantially across and within countries, calling for spatially targeted risk reduction and adaptation options.</p><p>Findings from this study underline the relevance of analyzing drought risk from a holistic and integrated perspective that brings together data from different sources and disciplines and based on a spatially explicit approach. Being based on open-source data, the approach allows for reproduction in varying regions and for different spatial scales, and can serve as a blueprint for future drought risk assessments for other affected sectors, such as water supply, tourism, or energy. By providing information on the underlying drivers and patterns of drought risk, this approach supports the identification of priority regions and provides entry points for targeted drought risk reduction and adaptation options to move towards resilient agricultural systems.</p>


2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Wenjuan Huang ◽  
Benjamin Z. Houlton ◽  
Alison R. Marklein ◽  
Juxiu Liu ◽  
Guoyi Zhou

2019 ◽  
Author(s):  
Bruno Ringeval ◽  
Marko Kvakić ◽  
Laurent Augusto ◽  
Philippe Ciais ◽  
Daniel Goll ◽  
...  

Abstract. Crossed fertilization additions are a common tool to assess nutrient interaction in a given ecosystem. Such fertilization experiments lead to the definition of nutrient interaction categories: e.g. simultaneous co-limitation, single resource response, etc. (Harpole et al., 2011). However, the implications of such categories in terms of nutrient interaction modeling are not clear. To this end, we developed a theoretical analysis of nitrogen (N) and phosphorus (P) fertilization experiments based on the computation of ratios between plant demand and soil supply for each nutrient. The theoretical analysis is developed following two mathematical formalisms of interaction: Liebig's law of minimum and multiple limitation hypothesis. As results of the theoretical framework, we defined the corresponding between most Harpole categories and the values of the limitation by each nutrient when considered alone in the control experiment (i.e. without additional nutrient supply). We showed that synergistic co-limitation could occur even using Liebig's formalism under certain conditions as a function of the amount of N and P added in fertilization experiments. We then applied our framework with global maps of soil supply and plant demand for croplands to achieve their potential yield. This allowed us to estimate the global occurrence of each limitation category, for each of the possible interaction formalism. We found that a true co-limitation could affect a large proportion of the global crop area (e.g. ~ 42 % for maize) if multiple limitation hypothesis is assumed. Our work clarifies the conditions required to achieve N and P co-limitation as function of the interaction formalism. Combined with compilation of field trials in cropland, our study would improve our understanding of nutrient limitation in cropland at the global scale.


2012 ◽  
Vol 17 (5) ◽  
pp. 646-654 ◽  
Author(s):  
Roel J. K. Helmes ◽  
Mark A. J. Huijbregts ◽  
Andrew D. Henderson ◽  
Olivier Jolliet

Sign in / Sign up

Export Citation Format

Share Document