Isotopic and elemental characterization of colloidal organic matter from the Chesapeake Bay and Galveston Bay

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dc.acquisition-srcDownloaded from-Web of Scienceen_US
dc.call-noen_US
dc.contract-noen_US
dc.contributor.authorGuo LDen_US
dc.contributor.authorSantschi PHen_US
dc.contributor.otherMarine Chemistryen_US
dc.date.accessioned2010-02-15T17:17:22Z
dc.date.available2010-02-15T17:17:22Z
dc.date.issued1997 Decen_US
dc.degreeen_US
dc.description1-15en_US
dc.description-otheren_US
dc.description.abstractIn order to investigate sources and turnover rates of dissolved organic matter from Chesapeake Bay and Galveston Bay, colloidal organic matter (COM) was isolated using cross-flow ultrafiltration and subsequently characterized for its elemental (C, N, and S) and isotopic (C-13 and C-14) composition. Distributions of dissolved organic carbon (DOC) in Chesapeake Bay showed a non-systematic variation, while in Galveston Bay, a non-conservative behavior of DOC with source inputs in the low salinity region was observed. Results of size fractionation of total organic carbon (TOC) revealed that, on average, particulate organic carbon (POC) comprised similar to 12% and 39% of the TOC pool in Galveston Bay and the Chesapeake Bay, respectively. Colloidal organic carbon (COG) between 1 kDa and 0.2 mu m (COC1) constituted similar to 53% and 35%, respectively, with 6-7% of TOC in the HMW fraction (10 kDa to 0.2 mu m, COC10), and only similar to 34% and 25%, respectively, of the TOC in the <1 kDa dissolved fraction. Values of Delta(14)C and C/N ratios of COM, in general, decreased from river to coastal seawater whereas delta(13)C values increased with increasing salinity, indicating that organic carbon sources changed from more terrestrial components to phytoplankton-derived sources during estuarine mixing. The distinct isotopic signature and elemental composition of riverine and estuarine COM also suggest that most riverine HMW COM could be removed or decomposed rapidly within the estuary. The fact that values of C/N ratios increased from particulate to HMW to medium MW COM suggest that reactivities of organic matter decrease with reducing size. While Delta(14)C values of COM1 were generally equivalent to contemporary ages, they were consistently lower for the COM10. Lower delta(14)C values and lower C/N ratios in the COM10 than in the COM1 suggest that most of the estuarine HMW COM is from older and more proteinaceous sources within the estuaries. We hypothesize that resuspended sedimentary organic matter or recycled older DOM is likely the source for COM10. (C) 1997 Elsevier Science B.Ven_US
dc.description.urihttp://gbic.tamug.edu/request.htmen_US
dc.historyen_US
dc.identifier.urihttp://hdl.handle.net/1969.3/23482
dc.latitudeen_US
dc.locationen_US
dc.longitudeen_US
dc.notesTimes Cited: 47ArticleEnglishGuo, L. DTexas A&M Univ, Dept Oceanog, 5007 Ave U, Galveston, TX 77551 USACited References Count: 51YL709PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSAMSTERDAMen_US
dc.placeen_US
dc.publisheren_US
dc.relation.ispartofseries51128.00en_US
dc.relation.urien_US
dc.scaleen_US
dc.seriesen_US
dc.subjectcolloids,dissolved organic carbonen_US
dc.subjectcolloidal organic carbonen_US
dc.subjectisotopesen_US
dc.subjectestuary,Chesapeake Bay,Galveston Bayen_US
dc.subjectSTABLE CARBONen_US
dc.subjectTRACE-METALSen_US
dc.subjectAMAZON RIVERen_US
dc.subjectestuariesen_US
dc.subjectWATERen_US
dc.subjectCOMPONENTSen_US
dc.subjectsedimentsen_US
dc.subjectNITROGENen_US
dc.subjectPARTICLESen_US
dc.subjectTRANSPORTen_US
dc.titleIsotopic and elemental characterization of colloidal organic matter from the Chesapeake Bay and Galveston Bayen_US
dc.typeJournalen_US
dc.universityen_US
dc.vol-issue59(1-2)en_US

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