Observational and modeling study of dry deposition on surrogate surfaces in a South China city: implication of removal of atmospheric crustal particles

Wai, Ka Ming; Leung, K.Y.; Tanner, Peter A.

doi:10.1007/s10661-009-0881-1

Cited by 9 publications

(5 citation statements)

References 30 publications

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“…Dry deposition is calculated by multiplying the area of the Tolo Harbor, deposition velocity of aerosols, the nutrient concentrations in aerosols, and the solubility of each nutrient, while wet deposition is estimated by multiplying the area of the Tolo Harbor, precipitation rate, and nutrient concentrations in the rainwater. The dry deposition velocities for NH 4 + and NO x − in Tolo Harbor area are 0.03 and 0.12 cm/s, respectively (Wai et al, ). The concentrations of NH 4 + and NO x − in aerosols of Hong Kong are ~ 3042.2 ± 438.7 and 3781 ± 415.4 ng/m 3 according to the data from 2010 to 2016 (EPD, ).…”

Section: Discussionmentioning

confidence: 99%

Seasonality of Nutrient Flux and Biogeochemistry in an Intertidal Aquifer

2018

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Biogeochemical reactions in coastal aquifers highly affect the nutrient flux associated with submarine groundwater discharge (SGD) to the ocean, which subsequently influences the oceanic environment and ecology. This study investigates a seasonal variation of SGD-derived nutrient flux to the ocean and nutrient biogeochemistry in an intertidal aquifer of Tolo Harbor, Hong Kong. The results show that the inventory of NO x À and PO 4 3À in the intertidal aquifer has a clear seasonality with a large inventory in summer, a small inventory in spring, and a median inventory in autumn and winter, respectively. Differently, the inventory of NH 4 + is large in winter and summer and small in spring and autumn, which results from the coupled effects of seasonal change of both production and removal of NH 4 + in the aquifer. The SGD-derived nutrient (NH 4 + , NO x À , and PO 4 3À ) flux is the highest in summer (271.71, 24.86, and 116.66 mmol·day À1 ·(m coastline) À1 ) and is the lowest in spring (114.83, 1.70, and 20.26 mmol·day À1 ·(m coastline) À1 ). The majority of SGD-derived nutrient flux is supported by the local remineralization of organic matter along with seawater infiltration. In autumn, the recharge of seawater induced by tidal pumping significantly shifts the biogeochemical balance of nutrients and is the major source of groundwater nutrients in the intertidal aquifer. Among the various nutrient fluxes (SGD, river discharge, atmospheric deposition, and benthic sediment diffusion) to Tolo Harbor, SGD-derived PO 4 3À flux is the second major source of seawater PO 4 3À in addition to benthic sediment diffusion. The PO 4 3À loading via SGD is of significance to the primary production in the phosphorus-limited environment in Tolo Harbor. After considering the natural attenuation of nutrients in a sandy/silty beach aquifer, this study suggests the overestimation of SGD-derived nutrient loading estimated previously that simply use average nutrient concentration of fresh SGD endmember and saline SGD endmember as the nutrient concentration of total SGD endmember.Plain Language Summary The biogeochemical reactions in the intertidal aquifer are the crucial influencing factors affecting the groundwater nutrients that are essential for oceanic environment and ecology. Seasonal hydrologic variations are of significance to the biogeochemical reactions in the aquifer and nutrient speciation and concentrations in coastal groundwater. The results of this study indicate that both nutrient inventories in the aquifer and nutrient fluxes to the sea are higher in summer and autumn than winter and spring. By comparing the nutrient flux carried by the submarine groundwater discharge with other pathways, nutrient flux carried by coastal groundwater is a major source of phosphorus in the sea and supports the primary production in the harbor, which can be demonstrated by the positive trend between the nutrient flux and chlorophyll-a concentration in seawater. However, the red tide occurrence in the harbor does not have a similar seasonal tr...

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Section: Discussionmentioning

confidence: 99%

Seasonality of Nutrient Flux and Biogeochemistry in an Intertidal Aquifer

2018

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“…Ammonium depositions to the northern SCS were slightly lower than those measured over the YS, ECS, and WNP (15-30 mmol N m −2 year −1 ), but considerably lower than those in coastal areas of China (up to 100 mmol N m −2 year −1 ). Similarly, the observed NO − 3 and NH + 4 deposition fluxes in the northern SCS were relatively lower than those (35-212 mmol N m −2 year −1 for nitrate and 36-163 mmol N m 2 year −1 for ammonium) in coastal urban stations in southern China (Jia and Chen, 2010;Wai et al, 2010). Such a spatial pattern with an offshore decreasing tendency implies that N r (including nitrate and ammonium) was essentially transported from the continent via the northeasterly winds during the winter monsoon.…”

Section: Implications Of Atmospheric N R Deposition To the South Chinmentioning

confidence: 90%

Isotopic composition of water-soluble nitrate in bulk atmospheric deposition at Dongsha Island: sources and implications of external N supply to the northern South China Sea

et al. 2014

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Abstract. Increased reactive nitrogen (Nr, NO3− &plus; NH4&plus;+ &plus; dissolved organic nitrogen) emission from the Asian continent poses profound threats to ecosystem safety from terrestrial throughout the ocean proper. To quantify atmospheric Nr input, diagnose its sources, and evaluate influence on marine nitrogen cycle of the South China Sea (SCS), an oligotrophic marginal sea adjacent to the emission hot spot China, we conducted measurements of concentrations of nitrate and ammonium as well as other major ions and dual isotopes of nitrate (δ15NNO3 and δ18ONO3) in atmospheric deposition collected from Dongsha Island off southern China. The δ15NNO3 and δ18ONO3 for dry deposition averaged at −2.8‰ and +58.8‰, ranging from −7.5 to +3.7‰ and from ∼ +17 to +88‰, respectively. Wet deposition, although with limited samples, showed a similar flux-weighted mean in δ15NNO3 (−2.6‰) yet a significantly higher mean in δ18ONO3 (+78.8‰). The dual isotope ratios showed an anti-correlation and an inverse seasonality; the δ15NNO3 values were higher in summer compared to those in winter, while the δ18ONO3 values were higher in winter than those in summer. In winter, not only dual isotopic compositions of nitrate but also the ammonium and nitrate dry deposition fluxes were relatively uniform, demonstrating a persistent influence of fossil fuel combustion sourced from Asian continental outflows via the northeasterly monsoon winds. More variable isotopic values in summer likely suggest varying sources and dynamical formation processes of dry deposition nitrate. Biomass burning and lightning are suggested to be responsible for the observed higher δ15NNO3 values in summer. Atmospheric nitrate and ammonium deposition together was estimated to be ∼50 mmol N m−2 year−1, with the dominance of nitrate in dry deposition but ammonium slightly higher in wet deposition. If not including this additional fertilization of atmospheric inorganic nitrogen deposition to enhance the carbon sequestration, CO2 release out of the SCS would be double than that of the present amount, 460 ± 430 mmol C m−2 year−1. Our study demonstrates that atmospheric deposition may serve as an important external Nr supplier to the SCS; however it is difficult to separate the isotopic signal from N2 fixation (−2–0‰) due to their similarity in δ15NNO3. More studies related to isotopic composition of nitrogen speciation in atmospheric Nr deposition, their relative contributions and source identification, and the role of typhoons in the SCS are required.

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“…Dry deposition is difficult to estimate and measurements are scarce in PRD. Wai et al (2010) reported dry deposition of NH þ 4 -N and NO À 3 -N measured at two Hong Kong Environmental Protection Department (EPD) sites (Central Western and Kwun Tong). The weekly dry deposition samples were collected by an automated wetÁdry sampler using a solid polyethylene as the surrogate surface.…”

Section: Comparison With Published Data In Prd Other Chinese Rapid-umentioning

confidence: 99%

“…Wai et al (2010) also compared the daily dry deposition measurements using a solid polystyrene surface and a water surface at an urban site in Hong Kong for about six months and found that the dry deposition fluxes of NH þ 4 -N and NO À 3 -N collected by water surface were about 14 and seven times those collected by the solid polystyrene surface, respectively. If applying these ratios to the Hong Kong EPD measurements (Wai et al, 2010), we find that Hong Kong had a closely comparable dry deposition flux of NH þ 4 -N, but a much higher dry deposition flux of NO À 3 -N than DHS and HM in this study. Table 3 presents the comparison of the annual dry deposition fluxes of reactive N in this study with the other sites in China and the other countries.…”

Section: Comparison With Published Data In Prd Other Chinese Rapid-umentioning

confidence: 99%

Atmospheric nitrogen deposition to forest and estuary environments in the Pearl River Delta region, southern China

Wang

Shao

et al. 2013

Tellus B: Chemical and Physical Meteorology

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Due to its significant ecological and climate consequences, atmospheric nitrogen (N) deposition is a growing global concern, especially in the severely N-polluted regions such as the Pearl River Delta (PRD) region of southern China. One-year measurements of reactive N species, including ammonium nitrogen ( -N), nitrate nitrogen (-N) and total organic nitrogen (ON) in dry and wet deposition, were conducted using an automated wet–dry sampler incorporated with a DDAS (dry deposition on aqueous surface) sampling device at Dinghushan (DHS), a natural forest site in the northwest of PRD and at Hengmen (HM), an estuary site in the south of PRD during 2006–2007. Total deposition fluxes of N at DHS and HM were up to 48.2 and 37.8 kg ha−1 yr−1, respectively, with most of the deposition occurring in the rainy season. Wet deposition was the dominant form, contributing 65–70% to the total deposition. -N was the largest contributor to the total N deposition at DHS (47%) due to significant influence of agriculture emissions. ON was the most important N component at HM (41%), which is probably attributed to the marine sources. However, -N deposition is increasing rapidly recently and is expected to be more important in the near future. The current N deposition level in PRD is much higher than those in Europe and North America. Great challenges exist in reducing reactive N emission in this region. Thus, a scenario of rising N deposition in PRD in the near future cannot be ruled out. The environmental consequences due to elevated N deposition should therefore be paid more attention in the future

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Observational and modeling study of dry deposition on surrogate surfaces in a South China city: implication of removal of atmospheric crustal particles

Cited by 9 publications

References 30 publications

Seasonality of Nutrient Flux and Biogeochemistry in an Intertidal Aquifer

Seasonality of Nutrient Flux and Biogeochemistry in an Intertidal Aquifer

Isotopic composition of water-soluble nitrate in bulk atmospheric deposition at Dongsha Island: sources and implications of external N supply to the northern South China Sea

Atmospheric nitrogen deposition to forest and estuary environments in the Pearl River Delta region, southern China

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