Simulation of marine and terrestrial organic carbon in the Pearl River Estuary in summer——distribution characteristics, contribution rate and migration and transformation processes
LIU Guang-zhou1, HU Jia-tang1,2,3, LI Shi-yu1,2
1. School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China;
2. Guangdong Province Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou 510275, China;
3. Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai), Zhuhai 519000, China
Based on a well-validated three-dimensional hydrodynamic-water quality model, this paper isolated marine and terrestrial organic carbon during summer in the Pearl River Estuary (PRE) to investigate their spatial patterns, relative contributions, and associated fluxes. Results showed a gradually decreasing (increasing) trend of terrestrial (marine) organic carbon from the river outlets to the continental shelf with a mean concentration of 1.45mg/L(0.97mg/L) and 0.87mg/L (1.05mg/L) at the surface and bottom water, respectively. In stratified regions, the concentrations of terrestrial (marine) organic carbon decreased rapidly (increased slowly) with depth, whereas in non-stratified regions the marine and terrestrial organic carbon were both well mixed in the whole water column. The relative contribution of marine organic carbon increased gradually from 4.43% at the inner Lingdingyang Bay to 81.20% at the east of outer Lingdingyang Bay and was lower at the surface than the bottom water with a vertical integrated contribution being 48.26%. The hydrodynamic conditions in the PRE was complicated. Under the effects of river runoff, tides, and monsoon, terrestrial organic carbon was transported offshore with a gradual decrease in its transport fluxes. However, the transport fluxes of marine organic carbon have a large heterogeneity in their spatial patterns. Specifically, marine organic carbon was transported offshore with a gradual increase in its transport fluxes along the pathway at the southwest of the PRE and in contrast was transported onshore with a gradual decrease in fluxes at the northwest. The biochemical reactivity of terrestrial organic carbon was relatively weak, and thus only a small fraction was consumed through the biochemical processes, leading to a dominant role of sedimentation in the migration and transformation of terrestrial organic carbon. Marine organic carbon was mainly controlled by the physical transport near the river outlets and the biochemical consumption at the continental shelf. In addition, the sedimentation effect of marine organic carbon was less profound and the biochemical effect was significantly more important when compared to terrestrial organic carbon.
刘广州, 胡嘉镗, 李适宇. 珠江口夏季海陆源有机碳的模拟研究——分布特征、贡献比重及其迁移转化过程[J]. 中国环境科学, 2020, 40(1): 162-173.
LIU Guang-zhou, HU Jia-tang, LI Shi-yu. Simulation of marine and terrestrial organic carbon in the Pearl River Estuary in summer——distribution characteristics, contribution rate and migration and transformation processes. CHINA ENVIRONMENTAL SCIENCECE, 2020, 40(1): 162-173.
张珊珊,线薇微,梁翠.2015年秋季长江口有机碳的分布特征及其影响因素[J]. 海洋环境科学, 2018,37(1):55-61. Zhang S S, Xian W W, Liang C. Distribution characteristics of total organic carbon and influence factors in the Yangtze River Estuary in autumn 2015[J]. Marine Environmental Science, 2018,37(1):55-61.
[2]
Bauer J E, Bianchi T S. Dissolved organic carbon cycling and Transformation[J]. Treatise on Estuarine and Coastal Science, 2011,5:7-67.
[3]
张龙军,宫萍,张向上.河口有机碳研究综述[J]. 中国海洋大学学报(自然科学版), 2005,35(5):737-744. Zhang L J, Gong P, Zhang X S. Study on the electron microscopyc sample preparation technology of apostichopus japonicus coelomocytes[J]. Periodical of Ocean University of China, 2005,35(5):737-744.
[4]
Pierre R, Pierre F, Philippe C, et al. Anthropogenic perturbation of the carbon fluxes from land to ocean[J]. Nature Geoscience, 2013,6(8):597-607.
[5]
Raymond P A, Bauer J E. Use of 14C and 13C natural abundances for evaluating riverine, estuarine, and coastal DOC and POC sources and cycling:a review and synthesis[J]. Organic Geochemistry, 2001,32(4):469-485.
[6]
Wang B, Hu J T, Li S Y, et al. Impacts of anthropogenic inputs on hypoxia and oxygen dynamics in the Pearl River Estuary[J]. Biogeosciences, 2018,15(20):6105-6125.
[7]
Middelburg J J, Nieuwenhuize J. Carbon and nitrogen stable isotopes in suspended matter and sediments from the Schelde Estuary[J]. Marine Chemistry. 1998,60(3/4):217-225.
[8]
Kemp W M, Smith E M, Marvin D, et al. Organic carbon balance and net ecosystem metabolism in Chesapeake Bay[J]. Marine Ecology Progress Series. 1997,150(1):229-248.
[9]
Ronald B, Stephen O, Gerardo C. Bacterial carbon metabolism in the Amazon River system[J]. Limnology and Oceanography, 1995,40(7):1262-1270.
[10]
Mary A M, Wade M S, Joan E S. Biodegradation of riverine dissolved organic carbon in five estuaries of the Southeastern United States[J]. Estuaries. 1999,22(1):55-64.
[11]
Shi Z, Xu J, Huang X P, et al. Relationship between nutrients and plankton biomass in the turbidity maximum zone of the Pearl River Estuary[J]. Journal of Environmental Sciences, 2017,57(7):72-84.
[12]
Guo W, Ye F, Xu S, et al. Seasonal variation in sources and processing of particulate organic carbon in the Pearl River Estuary, South China[J]. Estuarine Coastal and Shelf Science, 2015,167(B):540-548.
[13]
Ni H, Lu F, Luo X, et al. Riverine inputs of total organic carbon and suspended particulate matter from the Pearl River Delta to the coastal ocean off South China[J]. Marine Pollution Bulletin, 2008,56(6):1150-1157.
[14]
蔡艳雅,韩舞鹰.珠江口有机碳的研究[J]. 海洋环境科学, 1990, 9(2):8-13. Cai Y Y, Han W Y. Study on organic carbon in the Pearl River Estuary[J]. Marine Environmental Science, 1990,9(2):8-13.
[15]
刘庆霞,黄小平,张霞,等. 2010年夏季珠江口海域颗粒有机碳的分布特征及其来源[J]. 生态学报, 2012,32(14):4403-4412. Liu Q X, Huang X P, Zhang X, et al. Distribution and sources of particulate organic carbon in the Pearl River Estuary in summer 2010[J]. Acta Ecologica Sinica, 2012,32(14):4403-4412.
[16]
郭威,叶丰,连忠廉,等.珠江口水体有机碳的季节性变化[J]. 热带海洋学报, 2016,35(4):40-50. Guo W, Ye F, Lian Z L, et al. Seasonal changes of organic carbon in the Pearl River estuary[J]. Journal of Tropical Oceanography, 2016, 35(4):40-50.
[17]
刘广州,胡嘉镗,李适宇,等.珠江口夏季有机碳的分布特征及其收支模拟研究[J]. 环境科学学报, 2018,39(4):1123-1133. Liu G Z, Hu J T, Li S Y, et al. Simulation of organic carbon distribution and budgets during summer in the Pearl River Estuary[J]. Acta Scientiae Circumstantiae, 2019,39(4):1123-1133.
[18]
胡嘉镗,李适宇.珠江三角洲一维盐度与三维斜压耦合模型[J]. 水利学报, 2008,39(11):1174-1182. Hu J T, Li S Y. One-dimensional salinity and three-dimensional baroclinic coupled model for simulating the flow in Pearl River delta[J]. Journal of Hydraulic Engineering, 2008,39(11):1174-1182.
[19]
Blumberg A F. A primer for ECOMSED user manual (Version 1.3)[M]. Mahwag, New Jersey:HydroQual Inc, 2002.
[20]
Fitzpatrick J J. User's guide for RCA release 3.0[M]. Mahwag, New Jersey:HydroQual Inc, 2004.
[21]
Di Toro D M. Sediment flux modeling[M]. New York:Wiley-Interscience, 2001:75-76.
[22]
刘德洪,胡嘉镗,李适宇,等.珠江口三维水质与底泥耦合模型的验证及应用[J]. 环境科学学报, 2016,36(11):4025-4036. Liu D H, Hu J T, Li S Y, et al. Validation and application of a three-dimensional coupled water quality and sediment model of the Pearl River Estuary[J]. Acta Scientiae Circumstantiae, 2016,36(11):4025-4036.
[23]
Chen W F, Cai P H, Dai M H, et al. 234Th/238U disequilibrium and particulate organic carbon export in the Northern South China Sea[J]. Journal of Oceanography, 2008,64(3):417-428.
[24]
Hung J J, Wang S M, Chen Y L. Biogeochemical controls on distributions and fluxes of dissolved and particulate organic carbon in the Northern South China Sea[J]. Deep Sea Research Part II:Topical Studies in Oceanography, 2007,54(14/15):1486-1503.
[25]
吴凯.近海环境中溶解有机物的生产和生物降解过程[D]. 厦门:厦门大学, 2017. Wu K. Production and degradation of dissolved organic matter in coastal systems[D]. Xiamen:Xiamen University, 2017.
[26]
张恒.珠江口夏季溶解氧收支模拟研究[D]. 广州:中山大学, 2009. Zhang H. Simulation study of dissolved oxygen budget in the Pearl River Estuary in summer[D]. Guangzhou:Sun Yat-sen University, 2009.
[27]
Wang B, Hu J T, Li S Y, et al. A numerical analysis of biogeochemical controls with physical modulation on hypoxia during summer in the Pearl River Estuary[J]. Biogeosciences, 2017,14(12):2979-2999.
[28]
Ye F, Guo W, Jia G D, et al. The sources and transformations of dissolved organic matter in the Pearl River Estuary, China, as Revealed by Stable Isotopes[J]. Journal of Geophysical Research:Oceans, 2018,123(9):6893-6908.
[29]
He B Y, Dai M H, Zhai W D, et al. Distribution, degradation and dynamics of dissolved organic carbon and its major compound classes in the Pearl River estuary, China[J]. Marine Chemistry, 2010,119(1-4):52-64.
[30]
刘华健,黄良民,谭烨辉,等.珠江口浮游植物叶绿素a和初级生产力的季节变化及其影响因素[J]. 热带海洋学报, 2017,36(1):81-91. Liu H J, Huang L M, Tan Y H, et al. Seasonal variations of chlorophyll a and primary production and their influencing factors in the Pearl River Estuary[J]. Journal of Tropical Oceanography, 2017,36(1):81-91.
[31]
Zhang X, Shi Z, Liu Q X, et al. Spatial and temporal variations of picoplankton in three contrasting periods in the Pearl River Estuary, South China[J]. Continental Shelf Research, 2013,56(15):1-12.
[32]
Lu Z M, Gan J P. Controls of seasonal variability of phytoplankton blooms in the Pearl River Estuary[J]. Deep Sea Research Part II:Topical Studies in Oceanography, 2015,117:86-96.
[33]
Hu J F, Peng P A, Jia G D, et al. Distribution and sources of organic carbon, nitrogen and their isotopes in sediments of the subtropical Pearl River estuary and adjacent shelf, Southern China[J]. Marine Chemistry, 2006,98(2-4):274-285.
[34]
Zhan W K, Wu J, Wei X, et al. Spatio-temporal variation of the suspended sediment concentration in the Pearl River Estuary observed by MODIS during 2003~2015[J]. Continental Shelf Research, 2019, 172(1):22-32.
[35]
Wong L A, Chen J C, Dong L X. A model of the plume front of the Pearl River Estuary, China and adjacent coastal waters in the winter dry season[J]. Continental Shelf Research, 2004,24(16):1779-1795.
[36]
Lai Z, Ma R, Gao G, et al. Impact of multichannel river network on the plume dynamics in the Pearl River estuary[J]. Journal of Geophysical Research Oceans, 2015,120(8):5766-5789.
[37]
Chen Z, Pan J, Jiang Y. Role of pulsed winds on detachment of low salinity water from the Pearl River Plume:upwelling and mixing processes[J]. Journal of Geophysical Research:Oceans, 2016,121(4):2769-2788.
[38]
Pan J, Gu Y. Cruise observation and numerical modeling of turbulent mixing in the Pearl River Estuary in summer[J]. Continental Shelf Research, 2016,120(1):122-138.
[39]
Harrison P J, Yin K, Lee J H W, et al. Physical-biological coupling in the Pearl River Estuary[J]. Continental Shelf Research, 2008,28(12):1405-1415.
[40]
Yin K D, Zhang J L, Qian P Y, et al. Effect of wind events on phytoplankton blooms in the Pearl River Estuary during summer[J]. Continental Shelf Research, 2004,24(16):1909-1923.
[41]
Singh S, Dash P, Sankar M S, et al. Hydrological and biogeochemical controls of seasonality in dissolved organic matter delivery to a blackwater estuary[J]. Estuaries and Coasts, 2019,42(2):439-454.
