Effects of Atmospheric Total Nitrogen Flux on Ocean Biogeochemistry and Ecosystems

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Project title

Code/計畫編號

MOST104-2611-M019-019

Translated Name/計畫中文名

全球變遷對西北太平洋臺灣海域海洋生物地球化學與生態系統影響之長期觀測與研究(Ⅱ)---子計畫：全球變遷因子對東海及西北太平洋黑潮海域大氣總有機氮通量關係之影響

Project Coordinator/計畫主持人

Hung-Yu Chen

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Marine Environmental Informatics

Website

https://www.grb.gov.tw/search/planDetail?id=11578322

Year

2015

Start date/計畫起

01-08-2015

Expected Completion/計畫迄

01-07-2016

Bugetid/研究經費

1265千元

ResearchField/研究領域

海洋科學
大氣科學
自然生態保育

"臺灣地處東亞，位於歐亞大陸與太平洋的交界，氣候上屬於東亞季風區，冬季盛行東北季風，夏季盛行西南季風。由於本區域内，受到陸源物質與人類活動影響甚鉅(Chen et al., 2010);且東海為本區域中的一個大型邊緣海(marginal sea)，除了河川輸出影響外，區域内日漸嚴重的人為大氣汙染也將影響海洋生地化的循環。過去我們在本區域中的相關研究結果指出(Chen and Chen, 2008; Chen et al., 2010; Chen and Chen 2011)，本區域内氣膠在沙塵暴時期，陸源性物質是無機營養鹽的重要來源；在非沙塵時期，主要控制因子為地殼性來源、海洋性來源和燃燒性來源。在乾沉降中氮物種的通量計算，結果顯示無機氮與有機氮分別貢獻了 39.2±17.4和22.2±8.8 mmol m-2 yr-。此外，Chen et al. (2010) 利用超微過濾方式將水溶性有機氮分為高、低分子量；結果顯示，在乾沉降中高分子量有機氮與低分子量有機氮濃度各占總水溶性有機氮的57±9%與43±9%。另以主要陰陽離子相關性分析發現，乾沉降粗顆粒中的高低分子量有機氮來源與沙塵和海鹽有關，細顆粒中的高低分子量有機氮來源與燃燒性有關。整體通量計算指出，高分子量有機氮(11.0 mmol m-2 yr-1)與低分子量有機氮(11.3 mmol m-2 yr—1)貢獻相同的量至大氣中。截至目前為止，這些氮物種僅限於乾沉降通量，尚未有任何區域内的濕沉降通量的數據，且對於濕沉降中的有機氮組成也鮮少探討。因此本研究將探討：（1)乾、濕沉降中無機與有機氮物種濃度與高低分子量有機氮之時序變化；（2)結合主要離子進一步了解氮物種的來源；（3)藉由相關性分析、主成分分析等統計工具，解釋氮物種與主要離子的相互關係；（4)計算總氮和各種氮物種包括高低分子量有機氮的通量及其變化以了解區域中氮物種的總通量現況。" "Located in East Asia, Taiwan is situated between Eurasia and the Pacific Ocean. The climate is affected by the East Asian monsoon, divided into the Northeast monsoon in the winter and the Southwest monsoon in the summer. The region is severely influenced by terrigenous materials and human activities (Chen et al., 2010). In addition, the marine biogeochemical cycles in the East China Sea, which is a large marginal sea in the region, are influenced by the river output and the intensifying anthropogenic air pollution in the region. Previous studies that we conducted in the region (Chen and Chen, 2008, 2011; Chen et al., 2010) have revealed that terrigenous matter is the primary source of the inorganic nutrients found in the aerosols collected in the region during dust storm periods, and that the main control factors during non-dust storm periods are crustal, marine, and combustion sources. The fluxes of the nitrogen species in dry deposition indicated that the concentrations of IN and ON were 39.2 ± 17.4 and 22.2 ± 8.8 mmol m-2 yr-1, respectively. In addition, Chen et al. (2010) used ultrafiltration method to separate WSON into high molecular weight-DON (HMW-DON) and low molecular weight-DON (LMW-DON). The HMW-DON and LMW-DON in dry deposition accounted for 57 ± 9% and 43 ± 9% of the total WSON, respectively. Analyzing the correlations between major cations and anions showed that the sources of the HMW-DON in dry coarse deposits were related to sandstorms and sea salt, whereas those in fine deposits were related to combustion. The total flux indicated that HMW-DON (11.0 mmol m-2 yr-1) and LMW-DON (11.3 mmol m-2 yr-1) contributed equally to the total DON concentration in the atmosphere. Currently, only the dry deposition fluxes of the nitrogen species have been explored, and statistics pertaining to the wet deposition fluxes worldwide are unavailable. Furthermore, studies on the ON composition in wet deposition are few. Therefore, this study investigated the changes in the concentrations of total nitrogen, IN and ON species and HMW-DON and LMW-DON in dry and wet depositions over time. The sources of nitrogen species were determined through analysis of major ions, and statistical instruments, such as correlation analysis and principal components analysis, were applied to ascertain the relationships among nitrogen species and major ions. The fluxes of various nitrogen species and HMW-DON and LMW-DON were calculated and variations in the fluxes were examined to ascertain the current total fluxes of nitrogen species in Northeast Asia."

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Effects of Atmospheric Total Nitrogen Flux on Ocean Biogeochemistry and Ecosystems

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