Studies On Inorganic Carbon In Offshore Environments

Directed by Song Jinming Margin seas play an important role in carbon cycling as the important sources and sinksof carbon. Much knowledge about it was acquired by scientists work, but most of thesestudies focus in CO2 in marine water and OC, IC in sediment. The study on carbon in offshoreand inorganic carbon forms in sediment is absence. This paper mainly study inorganic carbonforms and their contribution to carbon cycling in Changjiang River estuary and Jiaozhou Baysediment, and CO2 fluxes across air-water interface in Jiaozhou Bay. Innovation methods are studied firstly in this paper, direct determination of DIC in seawater, sequential extraction method of inorganic carbon in sediment and simultaneousdetermination of N, P in sediment are established by a series of experiments, In particular,inorganic carbon in sediment is first divided into five forms: NaCl form, NH3?H2O form,NaOH form, NH2OH?HCl form and HCl form by sequential extraction method. All thisbecome the functionof studying inorganic carbon in sea water and sediments. Water and sediment samples were collected in Changjiang River estuary cruise in May,2003, and three Jiaozhou bay cruises in June, July and September, 2003. Eh, Es and pH insediment were measured at the scene of sampling, and C, N, P, Si were measured in laboratory.Some new knowledge about the character of C source or sink in Jiaozhou Bay, the distributionof inorganic carbon forms, physical, chemical and biologic parameter's influence oninorganic carbon forms, the translation of inorganic carbon forms and the contribution tocarbon cycling is acquired. 1. The DIC distributions in seawater of Jiaozhou Bay in July and June is studied, CO2fluxes across air-water interface are calculated. The results show that the content of DICinside Bay is higher markedly than outside Bay in June, but the content of DIC outside Bay ishigher markedly than inside Bay in July. The trend of DIC distribution inside Bay is similar,viz. the content is the maximum in Northeast, then decrease gradually toward West, and thecontent is the minimum in West. The total trend of vertical distribution increases graduallyfrom surface to bottom. Jiaozhou Bay acts as a net source for atmospheric CO2 in July andJune. 2. The contents and distributions of inorganic carbon forms in Changjiang Riverestuary and Jiaozhou Baysediments are investigated. The character of content is NaCl form中国科学院海洋研究所博士学位论文　　　　　　　　　　　　　　　　　　　　　　近海环境中无机碳的研究form has more difference between section A and section B in Changjiang River estuary. Thedistribution is more complicated from West to East in section A, but the distribution is steadyfrom North to South in section B. Because the physical, chemical and biological condition isdifferent at every station, and their influence on every inorganic carbon forms is different, theverticaldistributions vary greatly, or may be contrast sometimes. The content of NaCl form, NH3?H2O formand NaOH formis similar, NH2OH?HCl formand HCl form is similar, but NH2OH?HCl formand HCl form is a majority of total inorganiccarbon, and the percentage vary in different region in Jiaozhou Bay. Vertical distribution ofany inorganic carbon except NH2OH?HCl formis coincidence in Jiaozhou Bay sediments. 3. The influence of pH, Eh, Es, water content, OC, ON, IN, OP and IP on inorganiccarbon are studied. These influencing factors can be divided in two groups, one group isphysical factor which include pH, Eh, Es and water content, the other is chemical groupwhich include OC, ON, IN, OP and IP. Physical factors affect inorganic carbon throughchemical factors, every factor have different effect on different form or the same form indifferent environment. The correlation between OC, P, N and inorganic carbon is positive in Chang...