Stream Water Nitrogen Eutrophication During Non-Irrigated Periods in a Paddy-Dominated Agricultural Basin in a Snowfall Area in Japan

Shinozuka, Ken’ichi; Chiwa, Masaaki; Nakamura, Koji; Nagao, Seiya; Kume, Atsushi

doi:10.1007/s11270-016-2906-z

Cited by 8 publications

(7 citation statements)

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“…However, the agricultural area in this basin consists mostly of paddy fields that can be a sink for In many cases, agricultural and urban areas are the large downstream N alternative sources [31]. However, the agricultural area in this basin consists mostly of paddy fields that can be a sink for NO 3 − because of net denitrification losses [32,33]. We examined the effects of paddy fields on NO 3 − concentration and isotopic signatures.…”

Section: Changes In the No3mentioning

confidence: 99%

Differences in Stream Water Nitrate Concentrations between a Nitrogen-Saturated Upland Forest and a Downstream Mixed Land Use River Basin

et al. 2017

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Nitrogen (N) saturation of upland forests has been assumed to be a substantial N source downstream. However, removal processes of N, including assimilation and denitrification in the downstream area, have not been clarified. To evaluate the N removal processes, nitrate and organic N concentrations, as well as nitrogen isotope ratio (δ 15 N) and oxygen isotope ratio (δ 18 O) of NO 3 − were measured along three rivers of Tatara River Basin, Japan where upland forests have already been N-saturated. Geographic information system (GIS) based topographical analysis was also conducted to evaluate the land use as urban area in relation to topography. In two of the three rivers, NO 3 − concentrations did not increase from upstream to downstream, despite the potential non-point N sources of urban areas. In another river, NO 3 − concentrations rather decreased.The values of δ 15 N and δ 18 O of NO 3 − and organic N concentrations suggested the presence of denitrification and assimilation over N pollutants in the river whose watersheds have a lower percentage of urban area. The lower percentage of urban area could be explained by the lower topographic index. This study concluded that the NO 3 − leaching from upland N-saturated forests was substantially assimilated or denitrified in the downstream area.

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Section: Changes In the No3mentioning

confidence: 99%

Differences in Stream Water Nitrate Concentrations between a Nitrogen-Saturated Upland Forest and a Downstream Mixed Land Use River Basin

et al. 2017

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“…Eutrophication is the process in which excess nutrients in a water body cause increased algal growth. As more biomass accumulates, sediments will get deposited and the water body will fill in (Shinozuka et al, 2016) as well as kill fish populations through lack of oxygen (Kangur et al, 2013). While eutrophication is a natural process, elevated nutrient concentrations due to fertilizer use in agricultural watersheds are rapidly increasing eutrophication rates and destroying aquatic habitats.…”

Section: Figure 11: Pickering Lands Airport Lands Reserve and Farm Fi...mentioning

confidence: 99%

“…While eutrophication is a natural process, elevated nutrient concentrations due to fertilizer use in agricultural watersheds are rapidly increasing eutrophication rates and destroying aquatic habitats. (Shinozuka et al, 2016;Dupas et al, 2015;Sharip et al, 2011).…”

Section: Figure 11: Pickering Lands Airport Lands Reserve and Farm Fi...mentioning

confidence: 99%

“…Nitrogen that is left in the soil after harvest typically experiences nitrification. This creates nitrate (NO3) which is very water soluble and has the potential to leach into the water table and contribute to eutrophication (Shinozuka et al, 2016& Daniel et al, 2009. As water percolates through the soil, either from rain fall or irrigation, soluble nitrates will combine with water and be transported through ground water flow or overland flow (Perlman, 2017).…”

Section: Nitrogenmentioning

confidence: 99%

“…The simplicity of computing the LI also presents some limitations. Shaffer and Delgado (2002) pointed out that this index does not consider fertility management practices which can have a significant impact on nitrate leaching (Shinozuka et al, 2016& Daniel et al, 2009.…”

Section: Nitrogen Leaching Indexmentioning

confidence: 99%

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Quantifying Ecosystem Services in an Agricultural Region in Southern Ontario Using a GIS-Based Approach and Open Source Data

Morgan¹

2022

Preprint

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There has been a land use battle in Pickering, Ontario between conservation groups and Transport Canada over the development of another International Airport in Southern Ontario on valuable farmland. The purpose of this research is to quantitatively assess the claims made by the conservation groups about the importance of the local farmland for maintaining the area’s water quality. The research has three objectives: (1) to determine whether or not the use of publicly available data and a GIS-based approach is appropriate for an ecosystem services survey related to water quality and nutrient loading in the area of the proposed airport; (2) to examine the relationship between crop yield and nutrient loading to understand if the ecosystem disservice related to excess nutrient export can be reduced without reducing crop yield; (3) to make spatially explicit recommendations on mitigating efforts that farmers in the PLA region take to reduce nutrient loading for both nitrogen and phosphorus. The results of this study suggest that the coarse resolution of publicly available data results in multicollinearity that renders the GIS-approach ineffective at quantifying spatial relationships among ecosystem (dis)services at this spatial scale. The GIS-based nutrient indices approach will likely be more effective at larger (e.g. multiple counties, provincial) spatial scales and is still a useful tool for identifying key areas for prioritizing the implementation of agricultural best management practices. The most affective mitigating efforts to reduce nutrient loading include changing fertilizer application methods to non-broadcast methods and to improve land use types in areas that are close to surface waters and headwaters.

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Molecular and stable isotopic evidence for the occurrence of nitrite-dependent anaerobic methane-oxidizing bacteria in the mangrove sediment of Zhangjiang Estuary, China

Zhang

Luo

Lin

et al. 2018

Appl Microbiol Biotechnol

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Nitrite-dependent anaerobic methane oxidation (n-damo), which is mediated by "Candidatus Methylomirabilis oxyfera-like" bacteria, is unique in linking the carbon and nitrogen cycles. However, the niche and activity of n-damo bacteria in the mangrove ecosystem have not been confirmed. Here, we report the occurrence of the n-damo process in the mangrove wetland of the Zhangjiang Estuary, China. The widespread occurrence of n-damo bacteria in mangrove wetland was confirmed using real-time quantitative polymerase chain reaction (qPCR) assay, which showed that the abundance of Methylomirabilis oxyfera-like bacterial 16S rRNA and pmoA genes ranged from 2.43 × 10 to 2.09 × 10 and 2.07 × 10 to 3.38 × 10copies per gram of dry soil in the examined sediment cores. The highest amount of targeting genes was all detected in the upper layer (0-20 cm). Phylogenetic analyses of n-damo bacterial 16S rRNA and pmoA genes illustrated the depth-specific distribution and high diversity of n-damo bacteria in the mangrove wetland. Stable isotope experiments further confirmed the occurrence of n-damo in the examined mangrove sediments, and the potential n-damo rates ranged from 25.93 to 704.08 nmol CO per gram of dry soil per day at different depths of the sediment cores, with the n-damo being more active in the upper layer of the mangrove sediments. These results illustrate the existence of active M. oxyfera-like bacteria and indicate that the n-damo process is a previously overlooked microbial methane sink in the mangrove wetlands.

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Stream Water Nitrogen Eutrophication During Non-Irrigated Periods in a Paddy-Dominated Agricultural Basin in a Snowfall Area in Japan

Cited by 8 publications

References 35 publications

Differences in Stream Water Nitrate Concentrations between a Nitrogen-Saturated Upland Forest and a Downstream Mixed Land Use River Basin

Differences in Stream Water Nitrate Concentrations between a Nitrogen-Saturated Upland Forest and a Downstream Mixed Land Use River Basin

Quantifying Ecosystem Services in an Agricultural Region in Southern Ontario Using a GIS-Based Approach and Open Source Data

Molecular and stable isotopic evidence for the occurrence of nitrite-dependent anaerobic methane-oxidizing bacteria in the mangrove sediment of Zhangjiang Estuary, China

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