Skip to main content

Advertisement

Log in

River Sources of Dissolved Inorganic Carbon in the Gulf of Trieste (N Adriatic): Stable Carbon Isotope Evidence

  • Published:
Estuaries and Coasts Aims and scope Submit manuscript

Abstract

River inputs can significantly affect carbon dynamics in the costal ocean. Here, we investigate the influence of four rivers (Isonzo/Soča, Timavo/Reka, Rižana, and Dragonja) on inorganic carbon (C) in the Gulf of Trieste in the northern Adriatic Sea using stable isotope signatures of dissolved inorganic carbon (δ13CDIC). In 2007, rivers exported 1.03 × 1011 g C in the form of dissolved inorganic carbon (DIC) to the Gulf of Trieste with the lowest export observed in the Dragonja and the highest in the Isonzo/Soča. River plumes were associated with higher total alkalinity (TA) and pCO2 values compared with Gulf of Trieste waters, but their inputs showed high spatial variability. The δ13CDIC values and the isotopic mass balance suggested that river input during the spring of 2007 represented about 16 % of DIC at our study site VIDA, located in the southeastern part of the Gulf of Trieste. During autumn of 2007, the riverine contribution of DIC was less pronounced (3 %) although the river export of C was higher relative to the spring season. Convective mixing with the Gulf of Trieste waters and bora wind events appear to reduce the riverine contribution to the DIC system. Our results suggest that river plumes play an important role in C cycling in the Gulf of Trieste by direct inputs of higher riverine DIC and by increased biological uptake of DIC promoted by the supply of riverine nutrients.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5

Similar content being viewed by others

References

  • Amiotte Suchet, P., J.L. Probst, and W. Ludwig. 2003. Worldwide distribution of continental rock lithology: Implications for the atmospheric/soil CO2 uptake by continental weathering and alkalinity river transport to the oceans. Global Biogeochemical Cycles 17: 10.1029/2002GB001891.

  • Aldrian, E. et al. 2008. Spatial and seasonal dynamics of riverine carbon fluxes of the Brantas catchment in East Java. Journal of Geophysical Research 113: G03029, doi:10.1029/2007JG000626.

  • Andersson, A.J., F.T. Mackenzie, and A. Lerman. 2005. Coastal ocean and carbonate systems in the high CO2 world of the Anthropocene. American Journal of Science 305(9): 875–918.

    Article  CAS  Google Scholar 

  • Aucour, A.M., et al. 1999. Use of 13C to trace origin and cycling of inorganic carbon in the Rhône river system. Chemical Geology 159(1): 87–105.

    Article  CAS  Google Scholar 

  • Berner, K.A., and R.A. Berner. 1996. The global water cycle. New Jersey: Prentice-Hall. 397 pp.

    Google Scholar 

  • Borges, A.V. 2005. Do we have enough pieces of the jigsaw to integrate CO2 fluxes in the coastal ocean? Estuaries 28(1): 3–27.

    Article  CAS  Google Scholar 

  • Borges, A.V., B. Delille, and M. Frankignoulle. 2005. Budgeting sinks and sources of CO2 in the coastal ocean: Diversity of ecosystems counts. Geophysical Research Letters 32(14), L14601.

    Article  Google Scholar 

  • Borges, A.V., et al. 2006. Carbon dioxide in European coastal water. Estuarine, Coastal and Shelf Science 70: 375–387.

    Article  CAS  Google Scholar 

  • Bouillon, S., R.M. Connolly, and D.P. Gillikin. 2011. Use of stable isotopes to understand food webs and ecosystem functioning in estuaries. Treatise on Estuarine and Coastal Science 7: 143–173. doi:10.1016/B978-0-12-374711-2.00711-7.

    Article  Google Scholar 

  • Brunet, F., et al. 2005. δ13C tracing of dissolved inorganic carbon sources in Patagonian rivers (Argentina). Hydrological Processes 19(17): 3321–3344.

    Article  CAS  Google Scholar 

  • Cantoni, C., et al. 2012. Carbonate system variability in the Gulf of Trieste (North Adriatic Sea). Estuarine, Coastal and Shelf Science 115: 51–62.

    Article  CAS  Google Scholar 

  • Civita, M., et al. 1995. The Timavo hydrogeologic system: an important reservoir of supplementary water resources to be reclaimed and protected. Acta Carsologica 24: 169–186.

    Google Scholar 

  • Chen, C.T., and A.V. Borges. 2009. Reconciling opposite views on carbon cycling in the coastal ocean: Continental shelves as sinks and near-shore ecosystems as sources of atmospheric CO2. Deep-Sea Research Part II 56: 578–590.

    Article  CAS  Google Scholar 

  • Cozzi, S., et al. 2012. Recent evolution of river discharges in the Gulf of Trieste and their potential response to climate changes and anthropogenic pressure. Estuarine, Coastal and Shelf Science 115: 14–24. doi:10.1016/j.ecss.2012.03.005.

    Article  CAS  Google Scholar 

  • Cozzi, S., et al. 2004. Dynamics of the oceanographic properties during mucilage appearance in the northern Adriatic Sea: analysis of the 1997 event in comparison to earlier events. Journal of Marine Systems 50: 223–241.

    Article  Google Scholar 

  • DeGrandpre, M.D., et al. 2002. Air–sea CO2 fluxes on the US Middle Atlantic Bight. Deep Sea Research Part II: Topical Studies in Oceanography 49: 4355–4367.

    Article  CAS  Google Scholar 

  • De Vittor, C., A. Paoli, and S. Fonda Umani. 2008. Dissolved organic carbon variability in a shallow coastal marine system (Gulf of Trieste, northern Adriatic Sea). Estuarine, Coastal and Shelf Science 78: 280–290.

    Article  Google Scholar 

  • Dickson, A.G. 1990a. Standard potential of the reaction AgCl(s) + .5H2(g) = Ag(s) + HCl(aq) and the standard acidity constant of the ion HSO4− in synthetic sea water from 273.15 to 318.15 K. Journal of Chemical Thermodynamics 22: 113–127.

    Article  CAS  Google Scholar 

  • Dickson, A.G. 1990b. Thermodynamics of the dissociation of boric acid in synthetic seawater from 273.15 to 318.15 K. Deep Sea Research Part A Oceanographic Research Papers 37: 755–766.

    Article  CAS  Google Scholar 

  • Faganeli, J., et al. 2009. Carbon and nitrogen isotope composition of particulate organic matter in relation to mucilage formation in the northern Adriatic Sea. Marine Chemistry 114: 102–109.

    Article  CAS  Google Scholar 

  • Frankignoulle, M., et al. 1998. Carbon dioxide emission from European estuaries. Science 282(5388): 434–436.

    Article  CAS  Google Scholar 

  • Fonda Umani, S., et al. 2007. Major interannual variations in microbial dynamics in the Gulf of Trieste (northern Adriatic Sea) and their ecosystem implications. Aquatic Microbial Ecology 46: 163–175.

    Article  Google Scholar 

  • Grosbois, C., et al. 2000. Dissolved load of the Loire River: chemical and isotopic characterization. Chemical Geology 170: 179–201.

    Article  CAS  Google Scholar 

  • Gillikin, D.P., et al. 2006. Stable carbon isotopic composition of Mytilus edulis shells: relation to metabolism and δ13C of DIC and phytoplankton. Organic Geochemistry 37: 1371–1382.

    Article  CAS  Google Scholar 

  • Hélie, J.F., C. Hillaire-Marcel, and B. Rondeau. 2002. Seasonal changes in the sources and fluxes of dissolved inorganic carbon through the St. Lawrence River—isotopic and chemical constraint. Chemical Geology 186(1): 117–138.

    Article  Google Scholar 

  • Hellings, L., et al. 1999. Origin and fate of organic carbon in the freshwater part of the Scheldt Estuary as traced by stable carbon isotope composition. Biogeochemistry 47: 167–186.

    CAS  Google Scholar 

  • Hernándes-Ayon, M.J., et al. 2007. Estimating the contribution of organic bases from microalgae to the titration alkalinity in coastal seawaters. Limnology and Oceanography: Methods 5: 225–232.

    Article  Google Scholar 

  • Hrvatin, M. 1998. Discharge regimes in Slovenia. Geografski zbornik XXXVIII: 60–87.

    Google Scholar 

  • Kanduč, T., D. Kocman, and N. Ogrinc. 2008. Hydrogeochemical and stable isotope characteristics of the River Idrijca (Slovenia), the boundary watershed between the Adriatic and Black Seas. Aquatic Geochemistry 14(3): 239–262.

    Article  Google Scholar 

  • Kempe, S. 1982. Long-term records of CO2 pressure fluctuations in fresh waters. In Transport of carbon and minerals in major world rivers, ed. E.T. Degens, 91–323. SCOPE-UNEP: Hamburg.

    Google Scholar 

  • Kroopnick, P. 1974. Correlations between 13C and ΣCO2 in surface waters and atmospheric CO2. Earth and Planetary Science Letters 22(4): 397–403.

    Article  CAS  Google Scholar 

  • Kroopnick, P.M. 1985. The distribution of 13C of ΣCO2 in the world oceans. Deep-Sea Research Part A 32: 57–84.

    Article  CAS  Google Scholar 

  • Laruelle, G.G., et al. 2010. Evaluation of sinks and sources of CO2 in the global coastal ocean using a spatially-explicit typology of estuaries and continental shelves. Geophysical Research Letters 37(15).

  • Longinelli, A., and J.M. Edmond. 1983. Isotope geochemistry of the Amazon basin: a reconnaissance. Journal of Geophysical Research 88: 3703–3717.

    Article  CAS  Google Scholar 

  • Lueker, T.J., A.G. Dickson, and C.D. Keeling. 2000. Ocean pCO2 calculated from dissolved inorganic carbon, alkalinity, and equations for K1 and K2—Validation based on laboratory measurements of CO2 in gas and seawater at equilibrium. Marine Chemistry 70: 105–119.

    Article  CAS  Google Scholar 

  • Malačič, V., and B. Petelin. 2001. Gulf of Trieste. In Physical Oceanography of the Adriatic Sea: Past, Present and Future, ed. B. Cushman-Roisin, M. Gačić, P.-M. Poulain, and A. Artegiani, 167–177. Dordrecht, Netherlands: Kluwer Acad.

    Google Scholar 

  • Malačič, V., and B. Petelin. 2009. Climatic circulation in the Gulf of Trieste (northern Adriatic). Journal of Geophysical Research 114(C7), C07002.

    Google Scholar 

  • McElligott, S., et al. 1998. Discrete water column measurements of CO2 fugacity and pHT in seawater: A comparison of direct measurements and thermodynamic calculations. Marine Chemistry 60: 63–73.

    Article  CAS  Google Scholar 

  • Meybeck, M. 1982. Carbon, nitrogen, and phosphorus transport by world rivers. American Journal of Science 282(4): 401–450.

    Article  CAS  Google Scholar 

  • Meybeck, M. 1993. C, N, P and S in rivers: from sources to global inputs. In: Interactions of C, N, P and S Biogeochemical cycles and global change, 163–193. Berlin: Springer.

    Book  Google Scholar 

  • Millero, F.J., et al. 1993. Titration alkalinity of seawater. Marine Chemistry 44: 153–165.

    Article  CAS  Google Scholar 

  • Mucci, A. 1983. The solubility of calcite and aragonite in seawater at various salinity, temperatures, and one atmospheric total pressure. American Journal of Science 283: 780–799.

    Article  CAS  Google Scholar 

  • Moratti, J., and J.L. Probst. 2003. Silicate rock weathering and atmospheric/soil CO2 uptake in the Amazon basin estimated from the river water geochemistry: seasonal and spatial variations. Chemical Geology 197: 177–196.

    Article  Google Scholar 

  • Ogrinc, N., et al. 2008. Sources and transport of carbon and nitrogen in the River Sava watershed, a major tributary of the River Danube. Applied Geochemistry 23: 3685–3698.

    Article  CAS  Google Scholar 

  • Opsahl, S., R. Benner, and R. Amon. 1999. Major flux of terrigenous dissolved organic matter through the Arctic Ocean. Limnology and Oceanography 44: 2017–2023.

    Article  CAS  Google Scholar 

  • Parkhurst, D.L., and C.A.J. Appelo. 1999. User's guide to PHREEQC (version 2)—a computer program for speciation, batch—reaction, one—dimensional transport, and inverse geochemical calculations. Water-Resources Investigations Report 99–4259.

  • Pleničar, M., B. Ogorelec, and M. Novak. 2009. The Geology of Slovenia. Ljubljana: Geološki zavod Slovenije. 612 pp.

    Google Scholar 

  • Redfield, A.C. 1958. The biological control of chemical factors in the environment. American Scientist 46: 205–221.

    CAS  Google Scholar 

  • Robbins, L.L., et al. 2010. CO2calc—a user-friendly seawater carbon calculator for Windows, Max OS X, and iOS (iPhone): U.S. Geological Survey Open-File Report 2010–1280, 17 pp.

  • Salisbury, J., et al. 2009. Episodic riverine influence on surface DIC in the coastal Gulf of Maine. Estuarine, Coastal and Shelf Science 82: 108–118.

    Article  CAS  Google Scholar 

  • Salisbury, J., et al. 2008. Coastal acidification by rivers: A new threat to shellfish? EOS Transactions AGU 89(50): 513–528.

    Article  Google Scholar 

  • Sarmiento, J.L., and E.T. Sundquist. 1992. Revised budget for the oceanic uptake of anthropogenic carbon dioxide. Nature 356(6370): 589–593.

    Article  CAS  Google Scholar 

  • Sempéré, R., et al. 2000. Carbon inputs of the Rhone River to the Mediterranean Sea: biogeochemical implications. Global Biogeochemical Cycles 14(2): 669–681.

    Article  Google Scholar 

  • Smith, S.V., and J.T. Hollibaugh. 1993. Coastal metabolism and the oceanic organic carbon balance. Reviews of Geophysics 31(1): 75–89.

    Article  Google Scholar 

  • Solidoro, C., et al. 2009. Current state, scales of variability, and trends of biogeochemical properties in the northern Adriatic Sea. Journal of Geophysical Research 114, C07S91. doi:10.1029/2008JC004838.

  • Spiker, E.C., and L.E. Schemel. 1979. Distribution and stable-isotope composition of carbon in San Francisco Bay. In San Francisco Bay: The urbanized estuary, ed. T.J. Conomos, 195–212. San Francisco: American Association of Advance Science.

    Google Scholar 

  • Szramek, K., et al. 2011. Dolomite versus calcite weathering in hydrogeochemically diverse watersheds established on bedded carbonates (Sava and Soča rivers, Slovenia). Aquatic Geochemistry 17: 357–396.

    Article  CAS  Google Scholar 

  • Szramek, K., et al. 2007. Relative weathering intensity of calcite versus dolomite in carbonate-bearing temperate zone watersheds: Carbonate geochemistry and fluxes from catchments within the St. Lawrence and Danube river basins. Geochemistry, Geophysics, Geosystems 8, Q04002. doi:10.1029/2006GC001337.

    Article  Google Scholar 

  • Takahashi, T., et al. 2002. Global sea-air CO2 flux based on climatological surface ocean pCO2, and seasonal biological and temperature effects. Deep-Sea Research II 49: 1601–1622.

    Article  CAS  Google Scholar 

  • Tamše, S., et al. 2014. Stable isotopes as a tool for nitrogen source identification and cycling in the Gulf of Trieste (Northern Adriatic). Continental Shelf Research, in press.

  • Telmer, K., and J. Veizer. 1999. Carbon fluxes, pCO2 and substrate weathering in a large northern river basin, Canada: carbon isotope perspectives. Chemical Geology 159(1): 61–86.

    Article  CAS  Google Scholar 

  • Turk, D., J.W. Book, and W.R. McGillis. 2013. pCO2 and CO2 exchange during high bora winds in the Northern Adriatic. Journal of Marine Systems 117-118: 65–71. doi:10.1016/j.jmarsys.2013.02.010.

    Article  Google Scholar 

  • Turk, D., et al. 2010. Carbon dioxide variability and air-sea fluxes in the northern Adriatic Sea. Journal of Geophysical Research 115, C10043.

    Article  Google Scholar 

  • Wu, Y., et al. 2007. Sources and distribution of carbon within the Yangtze River system. Estuarine, Coastal and Shelf Science 71(1): 13–25.

    Article  Google Scholar 

  • Yang, C., K. Telmer, and J. Veizer. 1996. Chemical dynamics of the St. Lawrence riverine system: δDH2O, δ18OH2O, δ13CDIC, δ34Ssulfate, and dissolved 87Sr/86Sr. Geochimica et Cosmochimica Acta 60: 851–866.

    Article  CAS  Google Scholar 

Download references

Acknowledgments

This research was financially supported by the Slovenian Research Agency under Research Programmes P1-0143, Canada Excellence Research Chair (CERC) in Ocean Science and Technology and LDEO contribution #7773. Special thanks are given to Corey Lambert for providing laboratory analysis at the University of Michigan. The authors would like to thank Mateja Poje and Mojca Dobnikar Tehovnik from the Slovenian Environmental Agency for providing the river monitoring data. The authors are grateful to the Associate Editor and two anonymous reviewers for their marked interest, constructive comments, and suggestions that improved the manuscript.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Nives Ogrinc.

Additional information

Communicated by Alberto Vieira Borges

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Tamše, S., Ogrinc, N., Walter, L.M. et al. River Sources of Dissolved Inorganic Carbon in the Gulf of Trieste (N Adriatic): Stable Carbon Isotope Evidence. Estuaries and Coasts 38, 151–164 (2015). https://doi.org/10.1007/s12237-014-9812-7

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s12237-014-9812-7

Keywords

Navigation