Composition and variability in the export of biogenic silica in the Changjiang River and the effect of Three Gorges Reservoir

Ran, Xiangbin; L, Sen; Liu, Jun; Zang, Jiaye; Chen, Hong; Ma, Yi; Wang, Yibin

doi:10.1016/j.scitotenv.2016.07.125

Cited by 40 publications

(25 citation statements)

References 58 publications

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“…are transported in the form of aggregated flocs (Guo and He, 2011). For instance, there is a 77% reduction of total phosphorous and an 83% reduction of particulate phosphorous annually (Zhou et al, 2013) and also a substantial decrease of silica flux (Ran et al, 2016). These changes would have impacts on the biogeochemical cycling in the river-estuary-coastal ocean continuum (Zhang et al, 2015).…”

Section: Implications Of the Hydrological Changesmentioning

confidence: 99%

How have the river discharges and sediment loads changed in the Changjiang River basin downstream of the Three Gorges Dam?

Guo

Zhu

et al. 2018

Journal of Hydrology

132

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Streamflow and sediment loads undergo remarkable changes in worldwide rivers in response to climatic changes and human interferences. Understanding their variability and the causes is of vital importance regarding river management. With respect to the Changjiang River (CJR), one of the largest river systems on earth, we provide a comprehensive overview of its hydrological regime changes by analyzing long time series of river discharges and sediment loads data at multiple gauge stations in the basin downstream of Three Gorges Dam (TGD). We find profound river discharge reduction during flood peaks and in the wet-to-dry transition period, and slightly increased discharges in the dry season. Sediment loads have reduced progressively since 1980s owing to sediment yield reduction and dams in the upper basin, with notably accelerated reduction since the start of TGD operation in 2003. Channel degradation occurs in downstream river, leading to considerable river stage drop. Lowered river stages have caused a 'draining effect' on lakes by fostering lake outflows following TGD impoundments. The altered river-lake interplay hastens low water occurrence inside the lakes which can worsen the drought given shrinking lake sizes in long-term. Moreover, lake sedimentation has decreased since 2002 with less sediment trapped in and more sediment flushed out of the lakes. These hydrological changes have broad impacts on river flood and drought occurrences, water security, fluvial ecosystem, and delta safety.

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Section: Implications Of the Hydrological Changesmentioning

confidence: 99%

How have the river discharges and sediment loads changed in the Changjiang River basin downstream of the Three Gorges Dam?

Guo

Zhu

et al. 2018

Journal of Hydrology

132

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“…Despite of the high concentration of DSi (average at 100 μM; Ran et al, 2016) discharged by the Changjiang, the total flux of oceanic-sourced DSi from upwelled Kuroshio Waters (~5.8 × 10 11 mol/year; Liu et al, 2017) and Taiwan Strait Warm Water (TSWW; ~1.3 × 10 11 mol/year; Huang et al, 2019) largely surpasses the DSi from Changjiang discharge (1.0 × 10 11 mol/year; Ding et al, 2019), implying that diatom growth in the ECS may rely on different sources of DSi. Due to the preferential uptake of lighter isotopes by diatoms, the biological consumption of DSi should lead to an increase in the silicon isotopic composition of DSi (expressed as δ 30 Si(OH) 4 ), which can be described using a Rayleigh (closed system;de La Rocha et al, 1997) or steady-state (open system; Varela et al, 2004) model.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Silicic Acid Sources for Spring Diatom Blooms on the Continental Shelf: Insights FromStable Silicon Isotopes in the East China Sea

Zhang

Liu

et al. 2020

JGR Oceans

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The concentration of dissolved silicic acid (DSi) and its isotopic composition (δ30Si(OH)4) were determined for the East China Sea (ECS) shelf in the spring season with high spatial resolution. DSi concentrations and δ30Si(OH)4 values ranged from 1.3 to 116.5 μM and +0.85‰ to +2.53‰, respectively. An enrichment of 30Si was observed in most surface‐water samples compared with bottom waters. Several shallow‐water stations at water depths of <20 m reflected the overall control of biological utilization of DSi and regeneration of DSi from biogenic silica (BSi) on the distribution of δ30Si(OH)4 values. A seasonal difference in δ30Si(OH)4 values was observed in the euphotic zone of shelf waters, which is attributed mainly to continuous consumption of DSi in enhanced diatom blooms. The major water masses influencing the ECS shelf were characterized with distinct DSi concentrations and isotopic compositions. Using Si isotopic constraints, modeling of δ30Si(OH)4 values implied that utilization of DSi in the ECS occurred as if in a steady‐state mode. Riverine input was the major DSi source for the surface waters of inner‐shelf areas, as well as part of the middle‐ and outer‐shelf surface waters near the Changjiang River estuary. Upwelled Kuroshio Subsurface Water from the shelf break supported diatom growth in middle‐shelf surface waters. Taiwan Strait Warm Water and Kuroshio Surface Water were relatively oligotrophic, and their influence was confined to waters near the Taiwan Strait and the outer shelf and slope areas.

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“…Diatoms incorporate dissolved silicate into their frustules, being the main source of biogenic silica in riverine settings (Conley, 1997; Ran et al ., 2016) and under some circumstances accounting for the majority of the total silicon budget (Admiraal et al ., 1990; Conley 1997). Most of the biogenic silica in rivers is not actually associated to living diatoms, but to detrital particles that originate when diatoms die or are preyed upon (Krause et al ., 2010; Carbonell et al ., 2013).…”

Section: Discussionmentioning

confidence: 99%

Out of the blue: the independent activity of sulfur-oxidizers and diatoms mediate the sudden color shift of a tropical river

Arce-Rodríguez

Libby

Castellón

et al. 2022

Preprint

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Rio Celeste ("Sky-Blue River") is a river located in the Tenorio National Park (Costa Rica) that has become an important hotspot for eco-tourism due to its striking sky-blue color. A previous study suggested that this color is not caused by dissolved chemical species, but by precipitation of light-scattering aluminosilicate particles at the mixing point of two colorless streams, the acidic Quebrada Agria and the neutral Rio Buenavista. We now present microbiological information on Rio Celeste and its two tributaries, as well as a more detailed characterization of the particles that occur at the mixing point. Our results overturn the previous belief that the light scattering particles are formed by the aggregation of smaller particles coming from Rio Buenavista, and rather point to chemical formation of hydroxyaluminosilicate colloids with Quebrada Agria as the main contributor to the phenomenon, with Rio Buenavista acting as a secondary source of silica to the reaction. We also show how the sky-blue color of Rio Celeste arises from the tight interaction between chemical and biological processes. Sulfur-oxidizing bacteria generate an acidic environment in Quebrada Agria, which in turn cause dissolution and mobilization of aluminum and other metals, while in Rio Buenavista the growth of diatoms transforms dissolved silicon into colloidal biogenic forms. The local interaction between these two well-known biological activities gives rise to the unique Rio Celeste phenomenon, in what constitutes a textbook example of emergent behavior in environmental microbiology.

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Composition and variability in the export of biogenic silica in the Changjiang River and the effect of Three Gorges Reservoir

Cited by 40 publications

References 58 publications

How have the river discharges and sediment loads changed in the Changjiang River basin downstream of the Three Gorges Dam?

How have the river discharges and sediment loads changed in the Changjiang River basin downstream of the Three Gorges Dam?

Evaluation of Silicic Acid Sources for Spring Diatom Blooms on the Continental Shelf: Insights FromStable Silicon Isotopes in the East China Sea

Out of the blue: the independent activity of sulfur-oxidizers and diatoms mediate the sudden color shift of a tropical river

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