Influence of the agricultural land agglomeration to the nutrients of the river water in the Tokachi River basin

Yamazaki, Yoichi; Muneoka, Toshimi; Okazawa, Hiromu; Kimura, Masato; Tsuji, Osamu

doi:10.1007/s10333-016-0546-y

Cited by 4 publications

(10 citation statements)

References 57 publications

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“…Based on the TN and TP indicators, there is a potential risk of eutrophication incidence provided there is coincidence of other relevant factors (temperature, chlorophyll, water transparency, oxygen level, etc.). Similar concentrations of N and P, their ranges and contribution of individual forms were reported in other studies on this issue [55,58,90].…”

Section: Nutrient Status In the Canal Networksupporting

confidence: 86%

“…Similar results of N and P distribution in surface water were reported in other studies [16,21,35,39,56,75,80,91]. Leaching and runoff of nutrients from the surrounding farmlands after heavy precipitation, or inflow of water from the drainage system, can impact the seasonal distribution of nutrients in a waterbody as well [1,7,22,55,58,75].…”

Section: Tn:tp Ratiosupporting

confidence: 80%

“…The concentrations of N and P compounds, their total content in water (TN and TP) as well as their ratio (TN:TP mass ratio) is crucial in determining the ecological state of water bodies and in assessing possible limitations towards recovery from eutrophication [39,[49][50][51]. The relevance and importance of this issue has been reported in many studies dealing with the N and P concentration ratio [18,30,[52][53][54][55], which is an important component in studying the state and changes of trophic structure, biochemical cycles, and biodiversity [56]. The balance between N and P is an important ecological indicator of eutrophication and ecosystem productivity, known as the Redfield ratio [57].…”

Section: Introductionmentioning

confidence: 99%

“…The balance between N and P is an important ecological indicator of eutrophication and ecosystem productivity, known as the Redfield ratio [57]. Any deviation of the TN:TP ratio can result in favoring the intensive growth of certain phytoplankton species [36,55].…”

Section: Introductionmentioning

confidence: 99%

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Nitrogen and Phosphorus Concentrations and Their Ratios as Indicators of Water Quality and Eutrophication of the Hydro-System Danube–Tisza–Danube

et al. 2022

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Conserving clean and safe freshwater is a global challenge, with nitrogen (N) and phosphorus (P) as frequent limiting factors affecting water quality due to eutrophication. This paper provides a critical overview of the spatiotemporal variability in both nutrient concentrations and their total mass ratio (TN:TP) in the canal network of the Hydro system Danube–Tisza–Danube at 21 measuring locations monitored by the Environmental Protection Agency of the Republic of Serbia over a length of almost 1000 km, collected once a month during the last decade. A spatiotemporal variation in nutrient concentrations in the tested surface water samples was confirmed by correlations and cluster analyses. The highest TN concentrations were found in winter and early spring (non-vegetation season), and the highest TP concentrations in the middle of the year (vegetation season). The TN:TP mass ratio as an indicator of the eutrophication pointed out N and P co-limitation (TN:TP 8–24) in 64% of samples, N limitation (TN:TP < 8) was detected in 27% and P limitation (TN:TP > 24) in the remaining 9% of water samples. Such observations indicate slow-flowing, lowland water courses exposed to the effects of non-point and point contamination sources as nutrient runoff from the surrounding farmlands and/or urban and industrial zones, but further investigation is needed for clarification. These results are an important starting point for reducing N and P runoff loads and controlling source pollution to improve water quality and underpin recovery from eutrophication in the studied watershed.

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Section: Nutrient Status In the Canal Networksupporting

confidence: 86%

Section: Tn:tp Ratiosupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nitrogen and Phosphorus Concentrations and Their Ratios as Indicators of Water Quality and Eutrophication of the Hydro-System Danube–Tisza–Danube

et al. 2022

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“…Such data sets also indicate long-term changes in catchment responses and may contain evidence of rare events (e.g., severe droughts or floods) or rapid shifts in the system's behaviour [43][44][45]. Globally, studies have made use of long-term data in order to assess changes in river water quality including nitrate fluxes [46], hydrology [38], the effects of agriculture [47], the impact of reservoir construction on downstream flow regime [9] and the effects of land use changes [48]. In addition, the use of multivariate approaches and water quality indices, such as the Physicochemical Driver Assessment Index (PAI), allows for the interpretation of complex data sets in order to better understand the quality and ecological status of a studied ecosystem [3].…”

mentioning

confidence: 99%

Long-Term Water Quality Patterns of a Flow Regulated Tropical Lowland River

Necker

Neswiswi

Greenfield

et al. 2019

Water

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Floodplain ecosystems in Africa are under threat due to direct anthropogenic pressure and climate change. The lower Phongolo River and associated floodplain is South Africa's largest inland floodplain ecosystem and has been regulated by the Pongolapoort Dam since the 1970s. The last controlled flood release from the dam occurred in December 2014, after which a severe drought occurred and only a base flow was released. The central aims of this study were to determine the historic and present water quality state of the middle and lower Phongolo River and assess the possible effects of the most recent drought may have had. Historic water quality data (1970s to present) were obtained from monitoring stations within the Phongolo River catchment to assess the long-term water quality patterns. Using multivariate statistical analyses as well as the Physicochemical Driver Assessment Index (PAI), a water quality index developed for South African riverine ecosystems, various in situ and chemical water variables were analysed. Key findings included that the water quality of the middle and lower Phongolo River has degraded since the 1970s, due to increased salinity and nutrient inputs from surrounding irrigation schemes. The Pongolapoort Dam appears to be trapping nutrient-rich sediments leading to nutrient-depleted water entering the lower Phongolo River. The nutrient levels increase again as the river flows through the downstream floodplain through input from nutrient rich soils and fertilizers. The drought did not have any significant effect on water quality as the PAI remained similar to pre-drought conditions.Water 2020, 12, 37 2 of 22 impacts on the environment, as well as on the biophysical characteristics of a river both downstream and upstream of the impoundments [7][8][9][10]. Effects include altering the magnitude and velocity of floods and river flows either upstream or downstream of the dam [11], sediment trapping within the impoundment [10,12,13], loss of fertile topsoil downstream of the dam [8,14], nutrient retention within the impoundment [13], nutrient loading downstream of the dam and loss of biodiversity, particularly fish and macroinvertebrates [9,15,16]. The type and magnitude of these effects may differ between systems and is highly dependent on the size of the dam, whether hyper-or hypolimnetic discharge occurs, the purpose for which it was built, the type of river it is located on and the natural variability and function of rivers [12,17,18]. Through controlled flooding regimes, water may be released from an impoundment in a variety of patterns that differ from the natural hydrological regime of a river and thus impacts on the downstream ecosystem [12,[19][20][21], the most prominent impact being reduced downstream flow [8,22]. Reduced river discharge may result in a reduced flooding area and environmental flow, leading to variation in natural abiotic and biotic processes [23] such as nutrient cycling and the migration and spawning of fish [8,24].Low-flow drought disturbances are either seasonal or su...

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