Seasonal River Export of Nitrogen to Guanting and Baiyangdian Lakes in the Hai He Basin

2021 ◽  
Author(s):  
Jing Yang ◽  
Maryna Strokal ◽  
Carolien Kroeze ◽  
Xuanjing Chen ◽  
Zhaohai Bai ◽  
...  
Keyword(s):  
River Export

scholarly journals Variable impacts of contemporary versus legacy agricultural phosphorus on US river water quality

2019 ◽  
Vol 116 (41) ◽  
pp. 20562-20567 ◽  
Author(s):  
Sarah M. Stackpoole ◽  
Edward G. Stets ◽  
Lori A. Sprague
Keyword(s):  
Water Quality ◽  
Freshwater Ecosystems ◽  
Quality Improvements ◽  
Current Conservation ◽  
Continental Scale ◽  
Crop Uptake ◽  
P Fertilizer ◽  
River Export ◽  
Quality Response ◽  
External P Loading

Phosphorus (P) fertilizer has contributed to the eutrophication of freshwater ecosystems. Watershed-based conservation programs aiming to reduce external P loading to surface waters have not resulted in significant water-quality improvements. One factor that can help explain the lack of water-quality response is remobilization of accumulated legacy (historical) P within the terrestrial-aquatic continuum, which can obscure the beneficial impacts of current conservation efforts. We examined how contemporary river P trends (between 1992 and 2012) responded to estimated changes in contemporary agricultural P balances [(fertilizer + manure inputs)—crop uptake and harvest removal] for 143 watersheds in the conterminous United States, while also developing a proxy estimate of legacy P contribution, which refers to anthropogenic P inputs before 1992. We concluded that legacy sources contributed to river export in 49 watersheds because mean contemporary river P export exceeded mean contemporary agricultural P balances. For the other 94 watersheds, agricultural P balances exceeded river P export, and our proxy estimate of legacy P was inconclusive. If legacy contributions occurred in these locations, they were likely small and dwarfed by contemporary P sources. Our continental-scale P mass balance results indicated that improved incentives and strategies are needed to promote the adoption of nutrient-conserving practices and reduce widespread contemporary P surpluses. However, a P surplus reduction is only 1 component of an effective nutrient plan as we found agricultural balances decreased in 91 watersheds with no consistent water-quality improvements, and balances increased in 52 watersheds with no consistent water-quality degradation.

scholarly journals Reducing river export of nutrients and eutrophication in Lake Dianchi in the future

2020 ◽  
Vol 2 (1) ◽  
pp. 73-90 ◽  
Author(s):  
Chuan Ma ◽  
Maryna Strokal ◽  
Carolien Kroeze ◽  
Mengru Wang ◽  
Xiaolin Li ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Nutrient Management ◽  
Environmental Policies ◽  
Management Options ◽  
Lake Dianchi ◽  
Pollution Levels ◽  
The North ◽  
River Export ◽  
Advanced Wastewater Treatment ◽  
Sewage Systems

Abstract Lake Dianchi is severely polluted with nitrogen (N) and phosphorus (P). The effects of implementing environmental policies and technologies on future lake quality are not well understood. We analyse effects of environmental policies and technologies on future river export of nutrients into Lake Dianchi. We develop scenarios for 2050 and analyse these with the existing MARINA-Lakes model (Model to Assess River Inputs of Nutrient to lAkes). The scenarios differ in assumptions about future nutrient management in agriculture, sewage systems and mining. In the SSP3 (Shared Socio-economic Pathway 3) scenario, river export of nutrients to Lake Dianchi is projected to increase 1.4–4.4 times between 2012 and 2050. In the Current Policies scenario, rivers may export fewer nutrients than in SSP3, but this may not avoid eutrophication. Effects of improved nutrient management on river export of nutrients differ among nutrient forms, sub-basins and sources (e.g., urbanization in the north, agriculture in the middle and south). Pollution levels can be reduced below the 2012 level in an Optimistic scenario assuming advanced wastewater treatment, improved nutrient management in agriculture and no mining. However, even this may not completely prevent eutrophication. Preventing eutrophication requires even more efforts, for example, in implementing circular-oriented management options.

scholarly journals River export of nutrients and organic matter from the North Slope of Alaska to the Beaufort Sea

2014 ◽  
Vol 50 (2) ◽  
pp. 1823-1839 ◽  
Author(s):  
J. W. McClelland ◽  
A. Townsend-Small ◽  
R. M. Holmes ◽  
Feifei Pan ◽  
M. Stieglitz ◽  
...  
Keyword(s):  
Organic Matter ◽  
Beaufort Sea ◽  
North Slope ◽  
The North ◽  
North Slope Of Alaska ◽  
River Export

The MARINA-Plastic model: Global river export of macro- and microplastics from over 10,000 sub-basins to coastal seas

2021 ◽  
Author(s):  
Maryna Strokal ◽  
Paul Vriend ◽  
Jikke van Wijnen ◽  
Carolien Kroeze ◽  
Tim van Emmerik
Keyword(s):  
North America ◽  
Solid Waste ◽  
Case Studies ◽  
Coastal Waters ◽  
Model Performance ◽  
Point Sources ◽  
Plastic Pollution ◽  
Plastic Model ◽  
River Export ◽  
The Impact

<p>Plastics are found in different sizes in many rivers and coastal waters worldwide. Our understanding of the sources of this plastic is poor. Quantitative, and spatially explicit data on plastic loads is needed to design effective plastic pollution reduction strategies. One way to gather such data is through modeling studies. To this end, we develop the MARINA-Plastic model for macro- and microplastic. The MARINA-Plastic model quantifies annual river export of macro- and microplastic by source from sub-basins to coastal waters of the world. The model runs for over 10,000 sub-basins and considers point (e.g., sewage systems) and diffuse (e.g., mismanaged solid waste on land) sources of plastics in rivers. We evaluate and validate the model using a “building trust” approach. Evaluation results indicate the robustness of the model performance.</p><p>Results of the MARINA-Plastic model show that approximately 10% of all sub-basins are, today, responsible for over 90% of macroplastic inputs to rivers globally. Asia and Africa are responsible for approximately 80% of the plastic export by rivers globally. Coastal waters of Asia and Africa are predominantly polluted with macroplastics from diffuse sources in terms of mass, whereas coastal waters of Europe and North America are predominantly polluted with microplastics from point sources. Middle- and downstream activities contribute largely to coastal water pollution with plastics for selected case studies. These case studies are six large rivers, of which the drainage areas are divided into up-, middle- and downstream sub-basins. These rivers are the Mississippi (North America), Amazon (South America), Danube (Europe), Niger (Africa), Nile (Africa), and the Yangtze (Asia) rivers. Our analysis shows that reducing plastic pollution in coastal waters requires improvement of the wastewater treatment in Europe and North America and solid waste management in Asia and Africa.</p><p>We show that the MARINA-Plastic model is applicable to get a better understanding of the sources and the spatial variability of the plastic pollution in rivers and coastal waters. The model allows to analyse the impact of upstream activities on downstream plastic pollution and to explore effects of environmental policies on plastics in waters. This information can help to develop effective solutions for reducing future plastic pollution.</p>

scholarly journals Coupling global models for hydrology and nutrient loading to simulate nitrogen and phosphorus retention in surface water – description of IMAGE–GNM and analysis of performance

2015 ◽  
Vol 8 (12) ◽  
pp. 4045-4067 ◽  
Author(s):  
A. H. W. Beusen ◽  
L. P. H. Van Beek ◽  
A. F. Bouwman ◽  
J. M. Mogollón ◽  
J. J. Middelburg
Keyword(s):  
Surface Water ◽  
Nutrient Loading ◽  
Point Sources ◽  
Integrated Assessment Model ◽  
Assessment Model ◽  
Grid Cells ◽  
Model Image ◽  
P Content ◽  
River Export ◽  
Uptake Velocity

Abstract. The Integrated Model to Assess the Global Environment–Global Nutrient Model (IMAGE–GNM) is a global distributed, spatially explicit model using hydrology as the basis for describing nitrogen (N) and phosphorus (P) delivery to surface water, transport and in-stream retention in rivers, lakes, wetlands and reservoirs. It is part of the integrated assessment model IMAGE, which studies the interaction between society and the environment over prolonged time periods. In the IMAGE–GNM model, grid cells receive water with dissolved and suspended N and P from upstream grid cells; inside grid cells, N and P are delivered to water bodies via diffuse sources (surface runoff, shallow and deep groundwater, riparian zones; litterfall in floodplains; atmospheric deposition) and point sources (wastewater); N and P retention in a water body is calculated on the basis of the residence time of the water and nutrient uptake velocity; subsequently, water and nutrients are transported to downstream grid cells. Differences between model results and observed concentrations for a range of global rivers are acceptable given the global scale of the uncalibrated model. Sensitivity analysis with data for the year 2000 showed that runoff is a major factor for N and P delivery, retention and river export. For both N and P, uptake velocity and all factors used to compute the subgrid in-stream retention are important for total in-stream retention and river export. Soil N budgets, wastewater and all factors determining litterfall in floodplains are important for N delivery to surface water. For P the factors that determine the P content of the soil (soil P content and bulk density) are important factors for delivery and river export.

Seasonality in river export of nitrogen: A modelling approach for the Yangtze River

2019 ◽  
Vol 671 ◽  
pp. 1282-1292 ◽  
Author(s):  
Xuanjing Chen ◽  
Maryna Strokal ◽  
Carolien Kroeze ◽  
Lin Ma ◽  
Zhenyao Shen ◽  
...  
Keyword(s):  
Yangtze River ◽  
The Yangtze River ◽  
River Export ◽  
Modelling Approach

Fertilizer, landscape features and climate regulate phosphorus retention and river export in diverse Midwestern watersheds

2019 ◽  
Vol 146 (3) ◽  
pp. 293-309 ◽  
Author(s):  
Evelyn Boardman ◽  
Mohammad Danesh-Yazdi ◽  
Efi Foufoula-Georgiou ◽  
Christine L. Dolph ◽  
Jacques C. Finlay
Keyword(s):  
Phosphorus Retention ◽  
Landscape Features ◽  
River Export
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