Water Chemistry of the Middle Amur River

Nagao, Seiya; Yan, Baixing; Kim, Vladimir I.; Шестеркин, В. П.; Leveshina, Svetlana I.; Yoh, Muneoki; Suzuki, Takehito; Kodama, Hiroki; Terashima, Masanao; Seki, Osamu; Махинов, А. Н.

doi:10.1007/978-4-431-55245-1_5

Cited by 3 publications

(7 citation statements)

References 18 publications

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“…From spring to summer, increases in irradiance and temperature lead to the melting of sea ice, resulting in the formation of a pycnocline in surface waters of the Sea of the Okhotsk. Also impacting the region is the Amur River, the longest river (4350 km) in the far eastern region of Russia, supplying not only large volumes of freshwater (Ogi et al, 2001), but also high levels of nutrients including Fe and organic matter into the Sea of Okhotsk via the southwardflowing East Sakhalin Current which runs along the eastern coast of Sakhalin Island (Nishioka et al, 2007;Andreev and Pavlova, 2009;Nagao et al, 2010;Takao et al, 2014). According to Nagao et al (2010), Amur River water contains ca.…”

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confidence: 99%

Spatial variability in iron nutritional status of large diatoms in the Sea of Okhotsk with special reference to the Amur River discharge

et al. 2014

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Abstract. The Sea of Okhotsk is known as one of the most biologically productive regions among the world's oceans, and its productivity is supported in part by the discharge of iron (Fe)-rich water from the Amur River. However, little is known about the effect of riverine-derived Fe input on the physiology of the large diatoms which often flourish in surface waters of the productive continental shelf region. We conducted diatom-specific immunochemical ferredoxin (Fd) and flavodoxin (Fld) assays in order to investigate the spatial variability of Fe nutritional status in the microplanktonsized (20-200 µm; hereafter micro-sized) diatoms. The Fd index, defined as the proportion of Fd to the sum of Fd plus Fld accumulations in the cells, was used to assess their Fe nutritional status. Additionally, active chlorophyll fluorescence measurements using pulse-amplitude-modulated (PAM) fluorometry were carried out to obtain the maximum photochemical quantum efficiency (F v / F m ) of photosystem II for the total micro-sized phytoplankton assemblages including diatoms. During our observations in the summer of 2006, the micro-sized diatoms were relatively abundant (> 10 µg C L −1 ) in the neritic region, and formed a massive bloom in Sakhalin Bay near the mouth of the Amur River.

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confidence: 99%

Spatial variability in iron nutritional status of large diatoms in the Sea of Okhotsk with special reference to the Amur River discharge

et al. 2014

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“…Organic compounds can also be characterized with SEC-HPLC [ 37 , 38 ]. Six different peaks were detected ( Figure 2 ).…”

Section: Resultsmentioning

confidence: 99%

Sustainable Plant Growth Promotion and Chemical Composition of Pyroligneous Acid When Applied with Biochar as a Soil Amendment

Jindo

Goron

Kurebito³

et al. 2022

Molecules

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The pyrolysis of biomass material results in pyroligneous acid (PA) and biochar, among other by-products. In agriculture, PA is recognized as an antimicrobial agent, bio-insecticide, and bio-herbicide due to antioxidant activity provided by a variety of constituent materials. Application of PA to crop plants and soil can result in growth promotion, improved soil health, and reduced reliance on polluting chemical crop inputs. More detailed information regarding chemical compound content within PA and identification of optimal chemical profiles for growth promotion in different crop species is essential for application to yield effective results. Additionally, biochar and PA are often applied in tandem for increased agricultural benefits, but little is known regarding the optimal proportion of each crop input. This work reports on the effect of combined applications of different proportions of PA (200- and 800-fold dilutions) and chemical fertilizer rates (100%, 75%, 50%, and 0%) in the presence or absence of biochar on Komatsuna (Brassica rapa var. perviridis, Japanese mustard spinach) plant growth. To elucidate the chemical composition of the applied PA, four different spectroscopic measurements of fluorescence excitation were utilized for analysis—excitation-emission matrix, ion chromatography, high-performance liquid chromatography, and gas chromatography-mass spectrometry. It was determined that PA originating from pyrolysis of Japanese pine wood contained different classes of biostimulants (e.g., tryptophan, humic acid, and fulvic acid), and application to Komatsuna plants resulted in increased growth when applied alone, and in different combinations with the other two inputs. Additionally, application of biochar and PA at the higher dilution rate increased leaf accumulation of nutrients, calcium, and phosphorus. These effects reveal that PA and biochar are promising materials for sustainable crop production.

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“…Overall, the results of this study indicate that permafrost wetlands ( Mari ) in the Amur‐Mid Basin are important sources of dFe and DOC to rivers in summer. According to monitoring of dFe concentration at several stations along the main stem of the Amur River, dFe flux from the Amur‐Mid Basin to Lower Basin in summer was estimated to be 2.86 × 10 8 g day −1 , which dominates approximately 33% of dFe flux at the station closest to the river mouth (Nagao et al., 2007). Additionally, Levshina (2012) found that the share of Fe‐organic complexes to total dFe concentration in the Bureya River, which is a major tributary in the Amur‐Mid Basin, was higher than those in tributaries in the Amur‐Lower Basin.…”

Section: Discussionmentioning

confidence: 99%

“…This indicates that dFe, transported from the Amur‐Mid Basin, is highly stable during the river transport. In recent years, it is generally believed that non‐permafrost wetlands in the Amur‐Lower Basin are source of dFe to the Amur River (Nagao et al., 2007; Pan et al., 2011; Wang et al., 2012). To this understanding, this study proposes for the first time that permafrost wetlands ( Mari ) in the Amur‐Mid Basin are also important source of dFe to the Amur River and perhaps to the Sea of Okhotsk.…”

Section: Discussionmentioning

confidence: 99%

“…The Amur River Basin covers a huge area (approximately 2.1 million km 2 ) in eastern Eurasia, including the eastern Mongolian Plateau, and forms the border between the Russian Far East and northeastern China. Although there are various types of natural environments in the Amur River Basin, previous studies have indicated some important dFe sources to rivers (Nagao et al., 2007; Wang et al., 2012). For example, the Sanjiang Plain, a large wetland in northeastern China, supplies abundant dFe to the Songhua and Ussuri rivers, which are large tributaries of the Amur River (Wang et al., 2012).…”

Section: Introductionmentioning

confidence: 99%

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Permafrost Wetlands Are Sources of Dissolved Iron and Dissolved Organic Carbon to the Amur‐Mid Rivers in Summer

Tashiro,

Yoh,

Shesterkin

et al. 2023

JGR Biogeosciences

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Dissolved iron (dFe) transported by the Amur River greatly contributes to phytoplankton growth in the Sea of Okhotsk. Nevertheless, there has been little research on the source of dFe to rivers, especially in the Amur‐Mid Basin, which is situated in a sporadic permafrost area. In the Amur‐Mid Basin, permafrost generally exists in wetlands in flat valleys, and these permafrost wetlands could be a source of dFe to rivers. To assess the importance of permafrost wetlands for dFe export, we conducted a local survey on land and soil characteristics of wetlands, and moreover analyzed the chemical composition (dFe, dissolved organic carbon (DOC), pH, and electrical conductivity (EC)) of 24 rivers with different watershed sizes in summer. As a result of local survey, the thickly accumulated peat soils in the permafrost wetland were almost saturated and rich in organic matter from the surface to a greater depth near the permafrost table. In addition, the coverage of such permafrost wetlands in watersheds showed significant positive correlations with dFe (r2 = 0.67, p = 1.7e−6) and DOC (r2 = 0.48, p = 1.8e−4) and a negative correlation with EC (r2 = 0.52, p = 7.7e−5). The dFe concentration was also correlated well with DOC concentration (r2 = 0.68, p = 7.3e−7) but not correlated with pH and watershed area. These findings are the first to indicate that permafrost wetlands in the Amur‐Mid Basin considerably contribute to dFe and DOC export to rivers, and their coverage primarily determines riverine dFe and DOC concentrations in summer.

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Water Chemistry of the Middle Amur River

Cited by 3 publications

References 18 publications

Spatial variability in iron nutritional status of large diatoms in the Sea of Okhotsk with special reference to the Amur River discharge

Spatial variability in iron nutritional status of large diatoms in the Sea of Okhotsk with special reference to the Amur River discharge

Sustainable Plant Growth Promotion and Chemical Composition of Pyroligneous Acid When Applied with Biochar as a Soil Amendment

Permafrost Wetlands Are Sources of Dissolved Iron and Dissolved Organic Carbon to the Amur‐Mid Rivers in Summer

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