Cross-shelf and along-shelf nutrient fluxes derived from flow fields and chemical hydrography observed in the southern East China Sea off northern Taiwan
TL;DR: In this paper, the authors used phase-averaged current velocities measured with ship-borne ADCP on two rounds separated by 3.5 cycles of the dominant M2 tide.
About: This article is published in Continental Shelf Research.The article was published on 2000-03-01. It has received 153 citations till now. The article focuses on the topics: Hydrography & Upwelling.
Citations
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TL;DR: In this paper, the results of a box-model suggest that the East China Sea Shelf do likely not export substantial amounts of dissolved biogenic elements to the open Northwest Pacific Ocean.
385 citations
TL;DR: For example, during four seasonal cruises between December 1997 and October 1998, this article studied the chlorophyll a concentration, primary production, and environmental conditions over the entire shelf of the subtropical East China Sea (ECS).
Abstract: Chlorophyll a concentration, primary production, and environmental conditions over the entire shelf of the subtropical East China Sea (ECS) were studied extensively during four seasonal cruises between December 1997 and October 1998. Nutrient concentrations in the northwestern half of the shelf were enriched all year-round, but primary production showed high seasonal variations. Intensive primary production was mostly observed in summer at about 939 mg C m−2 d−1. On average, the value in summer was about 3 times higher than that in other seasons. Annual primary production was 155 g C m−2 y−1. In the southeastern half of the shelf, on the other hand, nutrient concentrations were seasonally variable, but primary production showed only slight seasonal variations with a mean value of 395 mg C m−2 d−1. Annual primary production was 144 g C m−2 y−1. The annual variations in shelf-averaged primary production can be well described with a normal distribution curve. For the entire shelf of the ECS, annual primary production was 145 g C m−2 y−1. The rate of primary production was regulated by seawater temperature from winter to early spring. The rate of primary production was, in turn, regulated by the availability of nutrients, especially phosphate, from summer to autumn. In addition, turbidity might also play a role in the regulation of primary production in the waters of the inner shelf.
374 citations
TL;DR: In this paper, the authors reviewed the most widely accepted facts about surface and subsurface temperature and salinity fronts in the Bohai, Yellow and East China seas and their seasonal variations.
358 citations
TL;DR: In this paper, the authors used acoustic Doppler current profilers (ADCPs) to estimate the throughflow transport in the Taiwan Strait and showed that the onshore Kuroshio intrusion across the shelf break increases from autumn to winter.
Abstract: Recent advances in ocean-circulation research on the Yellow Sea and East China Sea shelves are summarized. Observations using acoustic Doppler current profilers (ADCPs) suggest that the connectivity of mean-volume-transports is incomplete between the Tsushima (2.6 Sverdrups; 1 Sv = 106 m3/s) and Taiwan Straits (1.2 Sv). The remaining 1.4-Sv transport must be supplied by onshore Kuroshio intrusion across the East China Sea shelf break. The Yellow Sea Warm Current is not a persistent ocean current, but an episodic event forced by northerly winter monsoon winds. Nevertheless, the Cheju Warm Current is detected clearly regardless of season. In addition, the throughflow in the Taiwan Strait may be episodic in winter when northeasterly winds prevail. The throughflow strengthens (vanishes) under moderate (severe) northeasterly wind conditions. Using all published ADCP-derived estimates, the throughflow transport (V) in the Taiwan Strait is approximated as $$
V = V_0 + V_1 \cos [2\pi (t - K)/T],
$$
where V
0, V
1, K are 1.2 Sv, 1.3 Sv, and 157 days, respectively, t is yearday, and T is 365.2422 days (i.e., 1 year). The difference between the throughflow transports in the Tsushima and Taiwan Straits suggests that the onshore Kuroshio intrusion across the shelf break increases from autumn to winter. The China Coastal Current has been observed in winter, but shelf currents are obscure in summer.
199 citations
Cites methods from "Cross-shelf and along-shelf nutrien..."
...(1991) F91 (2) 1938 (9), 1987 (16) Zhao and Fang (1991) Z91 (1) and (2) The estimation synthesized by various observations including F91 Liu et al. (2000) L00 (3) 1994 (1), 1997 (1) Wang et al. (2003) W03 (3) 1999−2001 (40)...
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...(1991) F91 (2) 1938 (9), 1987 (16) Zhao and Fang (1991) Z91 (1) and (2) The estimation synthesized by various observations including F91 Liu et al. (2000) L00 (3) 1994 (1), 1997 (1) Wang et al....
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...Liu et al. (2000) used ship-mounted ADCPs to compute the detided volume transport through the Taiwan Strait in August 1994 and March 1997....
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TL;DR: In this article, the authors constructed sediment and carbon budgets for the East China Sea (ECS) Shelf based on up-to-date data and found that 15-20% of the carbon inventory is buried in the shelf sediment, while > 80% must be transported out of shelf area in the form of dissolved carbon.
Abstract: [1] Sediment and carbon budgets were constructed for the East China Sea (ECS) Shelf based on up-to-date data The total annual sediment flux in the ECS Shelf is approximately 96% of the terrestrial input There is high retention of sediment on the ECS Shelf owing to the broad nature of the shelf edge (ie, 500–600 km) and because of an along-shore sediment dispersal path driven by the East China Sea Coastal Current (ECSCC) and the Taiwan Warm Current (TWC) Organic carbon (OC) burial was also observed, based on the results for sediment accumulation and the OC proportion in surface sediment A total of 74 × 106 t of OC is preserved in shelf sediments Source discrimination of sedimentary OC revealed that the percentage of OC burial for both terrigenous and marine OC sources was higher than the global mean value, at 10% and 55%, respectively, presumably owing to high sediment accumulation High OC flux to sediment in the estuary and shelf break suggests that riverine discharge and upwelling of the Kuroshio intrusion are key factors regulating OC burial over the shelf Estimated using a mass balance model, 15–20% of the carbon inventory is buried in the shelf sediment, while >80% of the carbon inventory must be transported out of shelf area in the form of dissolved carbon (organic and inorganic) The accumulation of carbon in sediments and the outflow of dissolved carbon sustain a high carbon sink in the ECS
167 citations
References
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TL;DR: In this paper, the authors provided an independent estimate of the annual supply of onwelling nitrate from the deep sea to the shelves and found that it may balance the offshore flux of carbon, suggesting that the continental margins and deep sea are equally important in the carbon and nitrogen biogeochemical cycles.
Abstract: THE continental margins occupy less than 20% of the surface area of the world ocean, and it is widely assumed that they do not play a significant part in the oceanic biogeochemical cycles of carbon and nitrogen. Data from 32 sediment-trap moorings, 16 in the deep sea and 16 on the continental slope1, suggest that at an average depth of 2,650 m on the slope, the combined rain of surviving shelf and slope particles yields a mean carbon flux of 6.9 g C m−2 yr−1—about ten times that at the same average depth in the deep sea (0.8 g C m−2 yr−1). Because the area of the deep sea is about ten times greater than that of the continental slopes, using the sediment-trap data and assuming a carbon/nitrogen ratio of 5:1, the equivalent total particulate offshore nitrogen loss is 0.5 × 1014 g N yr−1 at 2,650 m. If these trap observations are generally representative of the oceans and continental margins, then the supply of dissolved nitrate to the overlying euphotic zones should also be similar. Here I provide an independent estimate of the annual supply of onwelling nitrate from the deep sea to the shelves and find that it may balance the offshore flux of carbon, suggesting that the continental margins and deep sea are equally important in the carbon and nitrogen biogeochemical cycles.
647 citations
"Cross-shelf and along-shelf nutrien..." refers background in this paper
...The continental margins of the ocean sustain an enhanced primary productivity due to rich supply of nutrients from terrestrial and marine sources (Walsh, 1991; Wollast, 1991, 1993)....
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01 Jan 1972
592 citations
"Cross-shelf and along-shelf nutrien..." refers background in this paper
..., Fan, 1979) or partly southward along the western wall (Nitani, 1972)....
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...Previous studies have suggested that the #ow in the Taiwan Strait in winter should be southward (e.g., Fan, 1979) or partly southward along the western wall (Nitani, 1972)....
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TL;DR: In this article, the spatial and temporal structure of the Changjiang (Yangtze River) discharge over the inner and mid continental shelf off eastern China has been analyzed using hydrographic and current meter data collected during June 1980, August 1981, and November 1981.
584 citations
"Cross-shelf and along-shelf nutrien..." refers background in this paper
...Chao (1991) has demonstrated how wind forcing may alter the #ow pattern on the shelf, which may in turn move riverine e%uents in di!erent directions on the shelf (Beardsley et al., 1985)....
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