Seasonal variations in the nitrogen isotopic composition of dissolved nitrate in the Changjiang River estuary, China

Yu, Haiyan; Yu, Zhiming; Song, Xiuxian; Cao, Xihua; Yuan, Yunbin; Lu, Guangyuan

doi:10.1016/j.ecss.2015.01.017

Cited by 35 publications

(43 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3,16 The average isotopic composition of ammonia fluctuates between −42.4 and 7.1‰ and for nitrate from −2 to 3‰. 15,17−19 The availability of both nitrogen sources led to a preferential incorporation of 14 N, which was amplified by the addition of soil-improving VC. This explains why the plants grown under the conventional inorganic soil treatment displayed the lowest δ 15 N air values.…”

Section: Resultsmentioning

confidence: 99%

Nitrogen Isotope Composition, Nitrogen Amount, and Fruit Yield of Tomato Plants Affected by the Soil–Fertilizer Types

et al. 2018

View full text Add to dashboard Cite

Tomatoes (Solanum lycopersicum) are heavy nutrient feeding crops and require high amounts of nitrogen to maximize fruit production. The type of nitrogen applied and timing of fertilizer applications are important to reduce losses due to volatilization and leaching. Previous research suggested that nitrogen stable isotopes are a useful fingerprinting system for indicating if a crop has been grown with synthetic or organic nitrogen applications. To study the effects of fertilization systems on nitrogen isotopic patterns, “Better Bush” tomatoes were grown in a 2 year greenhouse experiment to analyze nitrogen isotopic composition, nitrogen content, and fruit yield. Three main soil fertility treatments were evaluated, and the results were compared to those obtained on plants grown in unfertilized soil: conventional inorganic (synthetic Miracle Grow (MG)), organic (bonemeal and bloodmeal (BB), BB with liquid Earth Juice (BBL), BB with 25% vermicompost (VC), BBL with 25% VC, and 25% VC), and mixed (MG with 25% VC). The soil fertilizers, treated and untreated soil, immature and mature leaflets tomato fruit peels, and fruit juices were analyzed for both nitrogen isotope ratios and nitrogen concentrations. Plant δ15Nair decreased in the order organic treatment-no fertilizer-mixed treatment-conventional treatment. The average δ15Nair values in leaves, fruit peels, and juice from plants grown with organic treatments ranged from 4.5 to 11.9, 5.4 to 10.1, and 6.1 to 11.1‰, respectively, whereas in the case of the inorganic treatment, the average δ15Nair values varied between −3.0 and 0.4, −1.1 and 0.4, and −0.9 and 1.9‰, respectively. Plant nitrogen concentrations in tomato decreased in the following order (from highest to lowest): inorganic soil fertility treatment, mixed treatments, and organic and control (no fertilizer) treatment. The average weight %N values in leaves and fruit peels from plants grown with organic treatments ranged from 1.3 to 4.2 and 1.1 to 2.3%, respectively, whereas in the case of the inorganic treatment, the average weight %N values varied between 3.7 and 5 and 1.3 and 2.8%, respectively. Plants grown under organic treatments have higher δ15Nair, lower weight %N, and are enriched in 15N compared with the original soil than plants grown with inorganic fertilizer, suggesting that the synthetic nitrogen sources are more readily available for plant uptake than the organic ones. The addition of vermicompost increases both δ15Nair and weight %N in plants. Tomato fruit yields did not differ between cluster 1 and cluster 2 harvest, however, total tomato fruit yields differed indicating that synthetically fertilized plants produced the highest total yields (g) (P ≤ 0.05). However, all treatments with VC soil applications indicated an increase in the amount of plant nitrogen, fruit yield, soil cation exchange capacity, soil organic matter content, and released soil nitrogen. Nitrogen isotope ratios of tomatoes can be used to distinguish among various soil fertility treatments, therefore fingerprinting the organ...

show abstract

Section: Resultsmentioning

confidence: 99%

Nitrogen Isotope Composition, Nitrogen Amount, and Fruit Yield of Tomato Plants Affected by the Soil–Fertilizer Types

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Thus, the characteristics values in NKBC and KSSW were apparent to set. Compared with KSSW, values in the CDW have a broad range (δ 15 N‐

{NO}_{3}^{-}

= 7.3–12.9‰,

{NO}_{3}^{-}

= 66.7 µmol·L −1 for freshwater collected from the Changjiang River [ Li et al ., ]; δ 15 N‐

{NO}_{3}^{-}

= 3.2–3.8‰,

{NO}_{3}^{-}

= 84.14 µmol·L −1 for seawater collected from the Changjiang River estuary [ Liu et al ., ; Yu et al ., ]). In the same period with this investigation, we collected seawater samples in the Changjiang River estuary and adjacent sea area, and the results showed that

{NO}_{3}^{-}

concentrations was 79.01 µmol·L −1 and δ 15 N‐

{NO}_{3}^{-}

were 3.2‰ in the lowest salinity area (salinity = 11.6 [ Wang et al ., ]).…”

Section: Discussionmentioning

confidence: 99%

The effect of Kuroshio Current on nitrate dynamics in the southern East China Sea revealed by nitrate isotopic composition

Wang

Song

et al. 2016

JGR Oceans

Self Cite

View full text Add to dashboard Cite

In spring 2014 (May–June), in the southern East China Sea (ECS) and east of Taiwan, nutrient and isotope samples were collected and analyzed. Also, dissolved oxygen (DO), chlorophyll‐a, and physical parameters were determined. The Kuroshio subsurface water intruded into the ECS and separated into two branches on the continental shelf: the nearshore Kuroshio branch current (NKBC) and the offshore Kuroshio branch current (OKBC). Nitrate concentration in the Kuroshio subsurface water slightly decreased east of Taiwan by assimilation and was supplied by upwelling currents northeast of Taiwan. The variations of DO, nitrate, and nitrogen isotopes in the bottom water showed that continuous nitrification occurred in the NKBC after intrusion into the ECS. This process might contribute to the hypoxia zone near the coast of Zhejiang Province, China. Our results also indicated that internal nitrogen cycles appeared in NKBC since the isotope fractionation ratio of oxygen and nitrogen (18ɛ:15ɛ) in NO3− was 1.40. The NO3− flux and budget were calculated in the NKBC via numerical simulations. It demonstrated that at least ∼0.52 kmol NO3−·s−1 was produced by nitrification from DH9 to DH5 transect, and ∼0.11 kmol NO3−·s−1 was consumed in the DH4 transect. Moreover, according to the Rayleigh model, primary production in most of southern ECS was supported by the intrusion of the Kuroshio subsurface water, causing 5‰ isotope fractionation. In some of nearshore stations which located in the northern investigated area, the assimilated nitrate was contributed from both the NKBC and coastal currents originated from the Changjiang diluted water.

show abstract

“…The first work by Liu et al (2009) focused on surface waters and thus did not address identification of NO 3 À subsurface sources. Similar work by Yu et al (2015), again lacking measurements of δ 18 O NO3 , was limited in its assessment of the influence of nitrification, a common process in coastal waters (Dähnke et al, 2010;Ye et al, 2015). The only dual isotope work in the CJ plume was conducted by Chen et al (2013) in spring, a period during which active NO 3 À assimilation by phytoplankton is a dominant control.…”

Section: Study Areamentioning

confidence: 99%

Dual Isotope Measurements Reveal Zoning of Nitrate Processing in the Summer Changjiang (Yangtze) River Plume

Yan

Wan

et al. 2017

Geophysical Research Letters

View full text Add to dashboard Cite

Riverine nitrogen input into the coastal zone has increased remarkably in recent decades. Yet its transformation and recycling within hydrodynamically active regions remains unclear. Using observations of nitrate concentration and dual isotopic composition across the Changjiang River plume within a three end-member mixing model, we found deviations between the observed and expected values for mixing alone, revealing the nonconservative behavior of nitrate. Using cross correlations between concentrations and dual isotope deviations, we identified three nitrogen transformation zones, which correspond to separate portions of the plume. Nitrification and sedimentary denitrification occurred near the river mouth, nitrification prevailed further offshore under the plume, and finally, phytoplankton assimilation occurred in the outer surface plume (>100 km offshore), where it was fueled by nitrate that had already been strongly modified by microbial processes. Information was assembled into a conceptual model offering an overview of nitrogen transformations in a large river plume.

show abstract

Seasonal variations in the nitrogen isotopic composition of dissolved nitrate in the Changjiang River estuary, China

Cited by 35 publications

References 37 publications

Nitrogen Isotope Composition, Nitrogen Amount, and Fruit Yield of Tomato Plants Affected by the Soil–Fertilizer Types

Nitrogen Isotope Composition, Nitrogen Amount, and Fruit Yield of Tomato Plants Affected by the Soil–Fertilizer Types

The effect of Kuroshio Current on nitrate dynamics in the southern East China Sea revealed by nitrate isotopic composition

Dual Isotope Measurements Reveal Zoning of Nitrate Processing in the Summer Changjiang (Yangtze) River Plume

Contact Info

Product

Resources

About