Joint effect of freshwater plume and coastal upwelling on phytoplankton growth off the Changjiang River

Tseng, Yu Fang; Lin, Jun; Dai, Minhan; Kao, Shuh Ji

doi:10.5194/bgd-10-10363-2013

Cited by 9 publications

(13 citation statements)

References 55 publications

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“…The results indicated that nutrients were available in the bottom shelf waters. Previous studies have suggested that upwelling and diapycnal mixing provides a nutrient supply that maintains phytoplankton blooms (Tseng et al, 2014;D. Yang, Yin, et al, 2011;.…”

Section: Journal Of Geophysical Research: Oceansmentioning

confidence: 99%

“…intrusion determines the bottom nutrient conditions in the shelf (Fan & Song, 2014), which supplies nutrients for phytoplankton blooming through diapycnal mixing or upwelling (Tseng et al, 2014;Yang et al, 2013). On the other hand, strong tidal-induced mixing suspends the bottom sediments and forms a turbidity maximum zone (TMZ) in the inner estuarine area (Figure 1; Li & Zhang, 1998;Wu et al, 2012), while strong stratification restricts sediment resuspension into the upper layers in the plume area .…”

Section: Introductionmentioning

confidence: 99%

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Phytoplankton Blooms off a High Turbidity Estuary: A Case Study in the Changjiang River Estuary

Wang

Lin

et al. 2019

JGR Oceans

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The occurrence of phytoplankton blooms in estuarine and coastal waters is codetermined by the export of fluvial nutrients and other water properties such as turbidity. In this study, the Changjiang River Estuary was used as an example to investigate the intrinsic link between river plume dynamics, riverine nutrient loading, suspended sediment concentration, and phytoplankton blooms with a coupled hydrodynamic-sediment-ecosystem numerical model. Suspended sediment concentration from the sediment module was used to parameterize light attenuation in waters, which, in association with river plume dynamics, was found to impact phytoplankton distribution. Data that was collected in situ, in addition to satellite data for chlorophyll, nutrients, and suspended sediments, were used to validate the model, which performed well. The surface high chlorophyll centers exhibited a patch-like pattern from the northeast to the south off the Changjiang River mouth. The high chlorophyll concentration within the river plume was mainly determined by riverine nutrient exports, and potential phosphate limitation occurred away from the river mouth. The chlorophyll concentration decreased dramatically shoreward of the sediment front, which was controlled by the bottom river plume front. The bottom plume front was an intrinsic feature of the Changjiang River plume and similar river plume systems, which set a boundary separating the well-mixed (turbid) nearshore waters and stratified (clear) offshore waters. Without considering the sediment shading effect, the model yielded an unrealistic chlorophyll distribution with artificially high values in the turbid area. This indicated that light attenuation was a key factor limiting phytoplankton blooms in turbid river estuaries.Plain Language Summary In estuaries and coastal waters, the aquatic environment is affected by both riverine nutrient input and water properties such as turbidity. The associated river plume may play an essential role in controlling water properties, thus influencing the aquatic environment such as the algal blooms. In the current study, a well-validated hydrodynamic-sediment-ecosystem model was used to simulate phytoplankton blooms and the dynamic link with the Changjiang River plume. The results showed that the surface suspended sediment front was of vital importance in determining the shoreward boundary of the phytoplankton bloom area. Light attenuation due to high turbidity became a major factor limiting phytoplankton blooms in turbid nearshore waters. In environments with a strong tidal influence, the surface suspended sediment front was closely related to the bottom river plume front, which gave rise to differences in water stabilization and thus resulted in turbid conditions on either side. The results of this study provided a good reference for understanding the phytoplankton distribution characteristics in estuaries with high turbidity.

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Section: Journal Of Geophysical Research: Oceansmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Phytoplankton Blooms off a High Turbidity Estuary: A Case Study in the Changjiang River Estuary

Wang

Lin

et al. 2019

JGR Oceans

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“…Observations in the 2000s showed that the spring upwelling increases the phosphate, nitrate, and silicate concentrations in the mixed layer, followed by an increase in Chl a concentration, but the summer upwelling is relatively weaker and is strongly influenced by turbid Yangtze River plume water [Pei et al, 2009;Wei et al, 2011]. The Yangtze River plume water and coastal upwelling can significantly influence the horizontal and vertical heterogeneities of phytoplankton phosphorus deficiency in the Yangtze River plume [Tseng et al, 2014].…”

Section: Biogeochemical Responses To Upwellingmentioning

confidence: 99%

Progress on upwelling studies in the China seas

Wang

2016

Reviews of Geophysics

225

130

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East Asian marginal seas surrounding China exhibit rich ocean upwelling, mostly in response to the southwesterly summer monsoon. Upwelling in the China seas, namely, the South China Sea, the Taiwan Strait, the East China Sea, the Yellow Sea, and the Bohai Sea, has become increasingly important because the potential changes in the upwelling may have dramatic ecosystem, socioeconomic, and climate impacts. This paper reviews the progress of upwelling studies in the China seas since the year 2000, by presenting the principal characteristics and new understanding of 12 major upwelling regions in the China seas. Upwelling exhibits long-term variability at intraseasonal to multidecadal scales as well as short-term variability frequently caused by tropical cyclones. It is also associated with the El Niño-Southern Oscillation, local environmental variation, and biogeochemical factors. The coastal upwelling around Hainan Island and the upwelling or cold dome northeast of Taiwan Island are specifically highlighted because they have attracted great interest for decades. This paper summarizes upwelling mechanisms in terms of wind, topography, tide, stratification, and background flow, with applications mostly to the China seas. Finally, we propose some topics for future upwelling research, i.e., potential intensification of coastal upwelling under global climate change, downwelling, intrusion of upwelling into coastal embayments, and the influence of upwelling on fishery and biogeochemical processes.

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“…The freshwater discharge entering the East China Sea (ECS) is known to induce sizable upwelling off the mouth of Changjiang (e.g., Tseng et al 2013). Aside from the plume-induced upwelling, three patches of summer upwelling under normal conditions stand out in the ECS and Taiwan Strait.…”

Section: Introductionmentioning

confidence: 99%

Impacts of Tides and Typhoon Fanapi (2010) on Seas Around Taiwan

Ko¹,

Chao²,

Wu³

et al. 2016

Terr. Atmos. Ocean. Sci.

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We used satellite data, typhoon-resolving atmospheric forcing and a data assimilating ocean model, the East Asian Seas Nowcast/Forecast System (EASNFS), to investigate circulation and three upwelling regions perturbed by tides and Typhoon Fanapi (2010) in the seas around Taiwan. The three upwelling areas located off northeast Taiwan, off southeast China and over the Penghu Channel off southwest Taiwan are normally limited in expanse before Fanapi. The tidal currents enhance all three. To cope with typhoon strength atmospheric forcing, we applied typhoon-resolving Weather Research and Forecasting (WRF) model wind fields that significantly enhanced Fanapi-induced upwelling. Approaching Taiwan, Fanapi induces a cold wake spreading preferably on the right side of the essentially westward running track in the western Pacific. The three upwelling areas in the East China Sea and Taiwan Strait subsequently become expansive as Fanapi approaches and enters the Taiwan Strait. The mechanisms leading to normal or Fanapi-perturbed upwelling and circulation in seas around Taiwan, especially the latter two mentioned above, are suggested. In essence, Fanapi disrupts circulation in the Taiwan Strait, and also the Taiwan Strait outflow entering the East China Sea, leading to expanded upwelling areas. We also suggest that high-resolution wind and tides application is essential for the upwelling modeling study and also the general circulation in the region with and without typhoons.

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Joint effect of freshwater plume and coastal upwelling on phytoplankton growth off the Changjiang River

Cited by 9 publications

References 55 publications

Phytoplankton Blooms off a High Turbidity Estuary: A Case Study in the Changjiang River Estuary

Phytoplankton Blooms off a High Turbidity Estuary: A Case Study in the Changjiang River Estuary

Progress on upwelling studies in the China seas

Impacts of Tides and Typhoon Fanapi (2010) on Seas Around Taiwan

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