Stable isotopes of bulk organic matter to trace carbon and nitrogen dynamics in an estuarine ecosystem in Babitonga Bay (Santa Catarina, Brazil).
The biogeochemical processes affecting the transport and cycling of terrestrial organic carbon in coastal and transition areas are still not fully understood. One means of distinguishing between the sources of organic materials contributing to particulate organic matter (POM) in Babitonga Bay waters and sediments is by the direct measurement of delta(13)C of dissolved inorganic carbon (DIC) and delta(13)C and delta(15)N in the organic constituents. An isotopic survey was taken from samples collected in the Bay in late spring of 2004. The results indicate that the delta(13)C and delta(15)N compositions of OM varied from -21.7 per thousand to -26.2 per thousand and from +9.2 per thousand to -0.1 per thousand, respectively. delta(13)C from DIC ranges from +0.04 per thousand to -12.7 per thousand. The difference in the isotope compositions enables the determination of three distinct end-members: terrestrial, marine and urban. Moreover, the evaluation of source contribution to the particulate organic matter (POM) in the Bay, enables assessment of the anthropogenic impact. Comparing the depleted values of delta(13)C(DIC) and delta(13)C(POC) it is possible to further understand the carbon dynamic within Babitonga Bay.
Barros
Grace Virgínia
GV
Dipartimento di Scienze Ambientali, Università Ca' Foscari, Dorsoduro 2137, 30123 Venezia, Italy. vgbarros@gmail.com
Martinelli
Luiz Antonio
LA
Oliveira Novais
Therezinha M
TM
Ometto
Jean Pierre H B
JP
Zuppi
Gian Maria
GM
D001938:Brazil; D002244:Carbon / Q000032:analysis*; D002247:Carbon Isotopes / Q000032:analysis; D002614:Chelating Agents / Q000032:analysis*; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods; D006812:Humic Substances / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis*; D009587:Nitrogen Isotopes / Q000032:analysis; D012623:Seawater / Q000737:chemistry*; D012722:Sewage / Q000032:analysis; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*
D002247:Carbon Isotopes; D002614:Chelating Agents; D006812:Humic Substances; D009587:Nitrogen Isotopes; D012722:Sewage; D014874:Water Pollutants, Chemical; D002244:Carbon; D009584:Nitrogen