Abstract
Dissolved organic carbon (DOC) is an important component for both carbon cycle and energy balance. The concentration, UV absorbance, and export flux of DOC in the natural environment dominate many important transport processes. To better understand the temporal and spatial variation of DOC, 7 sites along the Lower Dagu River were chosen to conduct a comprehensive measurement from March 2013 to February 2014. Specifically, water samples were collected from the Lower Dagu River between the 26th and 29th of every month during the experimental period. The DOC concentration (CDOC) and UV absorbance were analyzed using a total organic carbon analyzer and the ultraviolet-visible absorption spectrum, and the DOC export flux was estimated with a simple empirical model. The results showed that the CDOC of the Lower Dagu River varied from 1.32 to 12.56 mg/L, consistent with global rivers. The CDOC and UV absorbance showed significant spatial variation in the Dagu River during the experiential period because of the upstream natural processes and human activities in the watershed. The spatial variation is mainly due to dam or reservoir constructions, riverside ecological environment changes, and non-point source or wastewater discharge. The seasonal variation of CDOC was mainly related to the source of water DOC, river runoff, and temperature, and the UV absorbance and humification degree of DOC had no obvious differences among months (P<0.05). UV absorbance was applied to test the CDOC in Lower Dagu River using wave lengths of 254 and 280 nm. The results revealed that the annual DOC export flux varied from 1.6 to 3.76 × 105 g C/km2/yr in a complete hydrological year, significantly lower than the global average. It is worth mentioning that the DOC export flux was mainly concentrated in summer (∼90% of all-year flux in July and August), since the runoff in the Dagu River took place frequently in summer. These observations implied environment change could bring the temporal-spatial variation of DOC and the exports, which would further affect the land-ocean interactions in the Lower Dagu River and the global carbon cycle.
Article PDF
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.Avoid common mistakes on your manuscript.
References
Bai J, Zhang G, Zhao Q, Lu Q, Jia J, Cui B, Liu X (2016). Depthdistribution patterns and control of soil organic carbon in coastal salt marshes with different plant covers. Sci Rep, 6: 34835
Clark J M, Lane S N, Chapman P J, Adamson J K (2008). Link between DOC in near surface peat and stream water in anupland catchment. Sci Total Environ, 404(2–3): 308–315
Guo W, Xu J, Wang J, Wen Y, Zhuo J, Yan Y (2010). Characterization of dissolved organic matter in urban sewage using excitation emission matrix fluorescence spectroscopy and parallel factor analysis. J Environ Sci (China), 22(11): 1728–1734
Harrison J A, Caraco N, Seitzinger S P (2005). Global patterns and sources of dissolved organic matter to the coastal zone: results from a spatially explicit, global model. Global Biogeochem Cycles, 19(4): 2488–2501
Hartmann J, Jansen N, Durr H H, Kempe S, Köhler P (2009). Global CO2 consumption by chemical weathering: What is the contribution of highly active weathering regions? Global Planet Change, 69(4): 185–194
Hedges J I, Keil R G, Benner R (1997). What happens to terrestrial organic matter in the ocean? Org Geochem, 27(5–6): 195–212
Jiang B (2007). Water quality evolvement and forecasting of the wellfield at the middle-low reach of Dagu River. Dissertation for Master Degree. Qingdao University, 1–3
Kong F, Xi M, Lu X, Jiang M, Li Y (2013). Spatial and temporal variation of dissolved organic carbon in soils of annular wetlands in Sanjiang Plain, China. Acta Pedologica Sinica, 50(7): 847–852
Li L L, Jiang T, Yan J L, Guo N, Wei S Q, Wang D Y, Gao J, Zhao Z (2014). Ultraviolet-Visible (UV-Vis) spectral characteristics of Dissolved Organic Matter (DOM) in soils and sediments of typical water-level fluctuation zones of Three Gorges Reservoir Areas. Environ Sci, 35(3): 933–941
Li S F, Yu Y C, He S (2002). Summary of research on dissolved organic carbon(DOC). Soil and Environmental Sciences, 11(4): 422–429
Li X, Yuan H, Li N, Song J (2008). Organic carbon source and burial during the past one hundred years in Jiaozhou Bay, North China. J Environ Sci (China), 20(5): 551–557
Lin J (2007). The DOC behavior and flux of Changjiang and Zhujiang river estuary. Fujian: Xiamen University, 23–46
Lou X D, Zhai S Q, Kang B, Hu L L (2014). Seasonal dynamic characteristics of dissolved organic carbon in Zoige Peatland and its impact factors. Research of Environmental Sciences, 27(2): 157–163
Ludwig W, Probst J L, Kempe S (1996). Predicting the oceanic input of organic carbon by continental erosion. Global Biogeochem Cycles, 10(1): 23–41
Martins O, Probst J L (1991). Biogeochemistry of major African rivers: carbon and mineral transport. In: Degens E T, Kempe S, Richey J E, eds. Biogeochemistry of Major World Rivers. SCOPE Report 42, Wiley, 127–155
Meybeck M (1993). Riverine transport of atmospheric carbon sources, global typology and budget. Water Air Soil Pollut, 70(1–4): 443–463
Mitsch W J, Gosselink J G (2007). Wetlands (4th ed). New York: John Wiley & sons, Inc., 582
Moody C S, Worrall F, Evans C D, Jones T G (2013). The rate of loss of dissolved organic carbon (DOC) through a catchment. J Hydrol (Amst), 492: 139–150
Moore T R (1987). An assessment of a simple spectrophotometric method for the determination of dissolved organic carbon in freshwaters. N Z J Mar Freshw Res, 21(4): 585–589
Maie N, Sekiguchi S, Watanabe A, Tsutsuki K, Yamashita Y, Melling L, Cawley K M, Shima E, Jaffé R (2014). Dissolved organic matter dynamics in the oligo/meso-haline zone of wetland influenced coastal rivers. J Sea Res, 91: 58–69
Patel N, Mounier S, Guyot J L, Benamou C, Benaim J Y (1999). Fluxes of dissolved and colloidal organic carbon, along the Purus and Amazonas rivers (Brazil). Sci Total Environ, 229(1–2): 53–64
Peterson B, Fry B, Hullar M, Saupe S,Wright R (1994). The distribution and stable carbon isotopic composition of dissolved organic carbon in estuaries. Estuaries, 17(1): 111–121
Ran L, Lu X X, Sun H, Han J, Li R, Zhang J (2013). Spatial and seasonal variability of organic carbon transport in the Yellow River, China. J Hydrol (Amst), 498: 76–88
Schelker J, Öhman K, Löfgren S, Laudon H (2014). Scaling of increased dissolved organic carbon inputs by forest clear-cutting–What arrives downstream? J Hydrol (Amst), 508: 299–306
Spitzy A, Leenheer J (1990). Dissolved organic carbon in rivers. In: Degens E T, Kempe S, Richey J E, eds. Scope (Scientific Committee on Problems of the Environment), No 42, Biogeochemistry of Major World Rivers. Chichester: Wiley, 213–232
Tao S, Liang T, Xu S, Di W (1997). Temporal and spatial variation of dissolved organic carbon content and its flux in yichun river. Acta Geogr Sin, 52(3): 254–261
Tian Y Q, Wang D, Chen R F, Huang W (2012). Using modeled runoff to study DOC dynamics in stream and river flow: a case study of an urban watershed southeast of Boston, Massachusetts. Ecol Eng, 42: 212–222
Wang C, Guo W, Guo Z, Wei J, Zhang B, Ma Z (2013). Characterization of dissolved organic matter in groundwater from the coastal Dagu River watershed, China using fluorescence excitation-emission matrix spectroscopy. Spectroscopy and Spectral Analysis, 33(9): 2460–2465
Wilson L, Wilson J, Holden J, Johnstone I, Armstrong A, Morris M (2011). Ditch blocking, water chemistry and organic carbon flux: Evidence that blanket bog restoration reduces erosion and fluvial carbon loss. Sci Total Environ, 409(11): 2010–2018
Worrall F, Davies H, Bhogal A, Lilly A, Evans M, Turner K, Burt T, Barraclough D, Smith P, Merrington G (2012). The flux of DOC from the UK Predicting the role of soils, land use and net watershed losses. J Hydrol (Amst), 448-449: 149–160
Xi M, Kong F, Lyu X, Jiang M, Li Y (2015). Spatial variation of dissolved organic carbon in soils of riparian wetlands and responses to hydro-geomorphologic changes in Sanjiang Plain, China. Chin Geogr Sci, 25(2): 174–183
Xi M, Lu X, Li Y, Kong F (2007). Distribution characteristics of dissolved organic carbon in annular wetland soil-water solutions through soil profiles in the Sanjiang Plain, Northeast China. J Environ Sci (China), 19(9): 1074–1078
Yin X, Lyu X, Liu X, Xue Z (2015). Influence of land use change on dissolved organic carbon export in Naoli River watershed, Northeast China. Chinese Journal of Applied Ecology, 26(12): 3788–3794
Zhang Y L (2008). The response of transport characteristics of riverine organic carbon to regional climate. Earth and Environment, 36(4): 348–355
Zhao K, Qiao L, Shi J, He S, Li G, Yin P (2015a). Evolution of sedimentary dynamic environment in the western Jiaozhou Bay, Qingdao, China in the last 30 years. Estuar Coast Shelf Sci, 163: 244–253
Zhao Q, Bai J, Liu P, Gao H, Wang J (2015b). Decomposition and carbon and nitrogen dynamics of Phragmites australis litter as affected by flooding periods in coastal wetlands. CLEAN-Soil, Air, Water, 43(3): 441–445
Acknowledgements
This work was supported by the National Natural Science Foundation of China (Grant No. 41101080) and Shandong Natural Science Foundation (No. ZR2014DQ028 and No. ZR2015DM004). We thank Prof. D. Yang and Dr. S. Sun for advice on the language and conclusions.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Xi, M., Kong, F., Li, Y. et al. Temporal-spatial variation of DOC concentration, UV absorbance and the flux estimation in the Lower Dagu River, China. Front. Earth Sci. 11, 660–669 (2017). https://doi.org/10.1007/s11707-017-0633-4
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11707-017-0633-4