Distribution of Carbon and Nitrogen as Indictors of Environmental Significance in Coastal Sediments of Weizhou Island, Beibu Gulf
| Autor: | Jiangbo Yang, Chao Cao, Hongshuai Qi, Zhiyi Tang, Kunxian Tang, Yuanmin Sun |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
lcsh:Hydraulic engineering
010504 meteorology & atmospheric sciences Geography Planning and Development Intertidal zone coastal sediments 010501 environmental sciences Aquatic Science 01 natural sciences Biochemistry law.invention lcsh:Water supply for domestic and industrial purposes Total inorganic carbon law lcsh:TC1-978 Radiocarbon dating organic carbon and nitrogen environmental significance Holocene Sea level 0105 earth and related environmental sciences Water Science and Technology Total organic carbon geography lcsh:TD201-500 geography.geographical_feature_category Estuary Oceanography Environmental science Seawater carbon and nitrogen isotopes inorganic carbon |
| Zdroj: | Water Volume 12 Issue 11 Water, Vol 12, Iss 3285, p 3285 (2020) |
| ISSN: | 2073-4441 |
| DOI: | 10.3390/w12113285 |
| Popis: | Carbon and nitrogen contents and their isotopic components, and AMS (Accelerator Mass Spectrometry) radiocarbon dating ages, were measured for 57 coastal sediments from Weizhou Island to analyze the distribution of total inorganic carbon (TIC) and its carbon and oxygen isotopic components (&delta 13Ccarb and &delta 18Ocarb), total organic carbon (TOC) and total nitrogen (TN) contents and their stable isotopic components (&delta 13CTOC and &delta 15NTN), and their environmental significance. The results showed that the oldest age of coastal sediments on Weizhou Island was 2750 cal. a BP (before present), and the average TIC contents of cores A1, A2, B1, C1, and D1 in the intertidal zone were all greater than 5%, where &delta 18Ocarb were enriched, whereas the TIC contents in cores A3, C2, and D2 of the supra-tidal zone were low, where &delta 18Ocarb were depleted. Moreover, TIC decreased sharply, 4.95% on average, to close to zero from the estuary to the upstream region in the C1-C2 section. The average C/N ratio was 7.02, and &delta 15NTN were between &minus 14.96&permil and &minus 27.26&permil 14.38&permil and 4.12&permil respectively. These measurements indicate that the TIC in coastal sediments mainly came from seawater. Cores A1, A2, and B1 in the northern intertidal zone exhibited organic terrestrial signals because of C3 and C4 plant inputs, which indicates that the important source on the northern coast of Weizhou Island came from island land but followed the decrease in C3 plants. The lacustrine facies deposits were mainly distributed in the upper reaches of the river, the northern coastline was advancing toward the sea, and part of the southwestern coastal sediments rapidly accumulated on the shore under the influence of a storm surge. The relative sea level of the Weizhou Island area has continuously declined at a rate of approximately 2.07 mm/a, using beach rock as a marker, since the Holocene. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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