Benthic nutrient fluxes in the intertidal flat within the Changjiang (Yangtze River) Estuary

Gao, Lei; Li, Daoji; Wang, Yanming; Liu, Yu; Kong, Dingjiang; Li, Mei; Li, Yun; Fang, Tao

doi:10.1007/s11631-008-0058-6

Cited by 5 publications

(3 citation statements)

References 59 publications

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“…3) and in the laboratory incubations (Fig. 4b) substantiate the significant denitrification processes occurring in the Dongtan marshes (Wang et al 2007;Gao et al 2008), which subsequently decomposed DOC, and perhaps CDOM compounds. The underlying mechanisms relating to the high denitrification rates and their effects on the amounts and properties of CDOM should be further examined in more detail.…”

Section: Comparison Between the Field Investigation And Laboratory Insupporting

confidence: 62%

Optical characterization of CDOM in a marsh-influenced environment in the Changjiang (Yangtze River) Estuary

et al. 2010

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To elucidate the influence of tidal marshes on the amount and chemical structure of chromophoric dissolved organic matter (CDOM) in adjacent coastal waters, surface water samples were collected along three crossmarsh transects in tidal marshes within the Changjiang Estuary. In addition, three sediment cores were collected from the marshes and incubated for 10 h in the laboratory after adding overlying tidal waters. Nutrients, DOC, absorption, fluorescence excitation-emission matrix (EEM) spectroscopy, and other parameters were measured in these samples, which clearly illustrated releases by the tidal marshes of DOC, and CDOM absorbent and fluorescent molecules. To characterize the chemical nature of the marsh-derived CDOM, variations in a suite of optical indices (including molar absorptivity, absorption spectral slope, fluorescence quantum yield, and fluorescence ratios between certain excitation/emission locations) in these samples were plotted against the offshore distance of the stations as well as the incubation time. From the literature, it has been suggested that these variations are closely associated with molecular weight, aromaticity, and humic/ fulvic or allochthonous/autochthonous ratios in the CDOM mixtures. This study showed that the CDOM fluorophores changed to more humic-like and were less protein-like from sea to land across the marsh gradients. Furthermore, subtractions between EEM spectra before and after laboratory incubations were applied to illustrate in greater detail the properties of the pure fluorescent compounds exchanged at the sediment-overlying water interface.

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Section: Comparison Between the Field Investigation And Laboratory Insupporting

confidence: 62%

Optical characterization of CDOM in a marsh-influenced environment in the Changjiang (Yangtze River) Estuary

et al. 2010

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“…Sediments play a significant role in contaminants cycling in urban runoff, which might act as a sink or a source of target elements on account of migration direction across the SWI [ 3 ]. Thus, significant heterogeneity in the temporal-spatial resolution of sediments and diverse biochemical interactions among various fractions in sediments result in complications in quantifying the labile fraction concentrations [ 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

In Situ Simultaneous Analysis of Nitrogen and Phosphorus Migration in Urban Black Odorous Runoff

Chen

Yao

Han

et al. 2022

IJERPH

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The extremely serious urban runoff eutrophication and black odorous phenomenon pose a significant threat to the lake aquatic ecosystem, resulting in a significantly increased frequency, magnitude, and duration of algal blooms in lakes. However, few investigations focus on small tributaries of the lakes, despite the ubiquity and potential local importance of these runoffs. Thus, the labile sediments NH4+-N, NO3−-N, PO43−, Fe2+, and S2− in black odorous runoff at Wuxi were overall analyzed at high resolution using diffusive gradients in thin films (DGT). The variations in labile N, P, Fe, and S distribution profiles at different sampling sites indicated high heterogeneity in sediments. The concentrations of labile P, Fe, and S showed synchronous variation from the sediment-water interface (SWI) up to −20 mm along sediment profiles. Moreover, there existed a significant positive correlation among labile P, Fe, and S concentrations (p < 0.05), which might represent typical odor compounds’ FeS and H2S synchronous release process in urban runoff. Furthermore, the apparent diffusion fluxes of labile P, Fe, and S across the SWI were all released upward, while fluxes of NH4+-N and NO3−-N release downward, indicating the sediments act as source and sink of P and N, respectively. Sediments’ potential for endogenous P and N fractions release results in the black−odorous water, and sediment finally abouchement the Taihu, which intensifies further lake eutrophication phenomenon.

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“…Because of the drainage into estuaries and coasts, the average tidal-flat water nitrate concentration is approximately 130 lmol L -1 (Chen et al 2005). So far, several studies have focused on denitrification, nitrous oxide exchange (Wang et al 2007a, b) and inorganic nutrient flux variations at the sediment-water interface using incubation experiments in the Yangtze marshes (Hou et al 2005;Chen et al 2005;Gao et al 2008). However, little is known about nutrient dynamic behavior in tidal marshes in response to nutrient level and structure of the Yangtze Estuary and its adjacent sea.…”

Section: Introductionmentioning

confidence: 99%

Nutrient dynamics in pore water of tidal marshes near the Yangtze Estuary and Hangzhou Bay, China

Wang

Zhou

et al. 2010

Environ Earth Sci

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Tidal marshes act as a buffer system for nutrients in the pore water and play important roles in controlling the budget of nutrients and pollutants that reach the sea. Spatial and seasonal dynamics of pore water nutrients were surveyed in three tidal marshes (Chongming Island, Hengsha Island, and Fengxian tidal flat) near the Yangtze Estuary and Hangzhou Bay from August 2007 to May 2008. Nutrient variations in pore water closely followed seawater quality in the estuaries, while the average concentration of NH 4? -N, the main form of inorganic nitrogen in pore water, was over two orders of magnitude higher than that in seawater which was dominated by nitrate. NH 4 ? -N export (13.81 lmol m -2 h -1 ) was lower than the import of (NO 3 -?NO 2 -)-N (-24.17 lmol m -2 h -1 ) into sediment over the 1-year period, hence reducing N-eutrophication in coastal waters. The export of SiO 3 2--Si and PO 4 3--P from tidal marshes regulated nutrient level and composition and lifted the ratio beyond potentidal element limitation in the coastal system. Moreover, macrophyte plants (Spartina alterniflora and Phragmites australis) played significant roles in controlling nutrient concentration in pore water and its exchange between marshes and estuaries. Fengxian marsh was characterized by higher nutrient concentrations and fluxes than other marshes in response to the more serious eutrophication in Hangzhou Bay than in the Yangtze Estuary.

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Benthic nutrient fluxes in the intertidal flat within the Changjiang (Yangtze River) Estuary

Cited by 5 publications

References 59 publications

Optical characterization of CDOM in a marsh-influenced environment in the Changjiang (Yangtze River) Estuary

Optical characterization of CDOM in a marsh-influenced environment in the Changjiang (Yangtze River) Estuary

In Situ Simultaneous Analysis of Nitrogen and Phosphorus Migration in Urban Black Odorous Runoff

Nutrient dynamics in pore water of tidal marshes near the Yangtze Estuary and Hangzhou Bay, China

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