Biogeochemical behavior of organic carbon in the Trinity River downstream of a large reservoir lake in Texas, USA

dc.acquisition-srcDownloaded from-Science Directen_US
dc.call-noen_US
dc.contract-noen_US
dc.contributor.authorWarnken KWen_US
dc.contributor.authorSantschi PHen_US
dc.contributor.otheren_US
dc.date.accessioned2010-02-15T17:16:45Z
dc.date.available2010-02-15T17:16:45Z
dc.date.issued2004 Augen_US
dc.degreeen_US
dc.description-en_US
dc.description-otheren_US
dc.description.abstractDissolved and particulate organic carbon concentrations were measured and annual loads estimated for the Trinity River, the main freshwater input source to Galveston Bay, which lies on the upper Gulf coast of Texas, USA, during 2000-2001. This river drains the forested lowlands south of a relatively large reservoir lake, Lake Livingston. A weak relationship between dissolved organic carbon (DOC) and QTR indicated hydrologic control but separation of the data, based on individual discharge events, was necessary to improve interpretation. For instance, the first rain of the season resulted in only a modest increase in DOC concentrations and led to an inverse relationship with discharge, due to decreased lateral flow and increased infiltration of rainwater, with the lower flows being more efficient at DOC leaching from soils. In contrast, a long duration high discharge river crest event resulted in an opposite trend, i.e. a linear increase in DOC with increasing discharge rates. A short duration high discharge tropical storm showed reduced Trinity River DOC concentrations and the highest POC concentrations measured, likely resulting from the relatively short duration, and minimal contact time, of this event. In contrast to DOC, the concentrations of particulate organic carbon, POC (mg C l-1) were linearly correlated to suspended particulate matter (SPM) concentrations and accounted for between 10 and 12% of the total suspended load at low discharge but decreased to ~2% at high discharge. This suggests dilution by larger particles with a reduced organic carbon content, possibly silicate minerals, more readily resuspended at elevated levels of discharge. The annual total organic carbon (TOC) load to Galveston Bay, estimated from the slope of the daily load vs. discharge relationship, was 11.2 x 1010 g C and calculated export coefficients (g C m-2 year-1) were in good agreement with previous results. Using this relationship, accurate assessments of TOC flux inputs to Galveston Bay over the past quarter-century and in the future are possible by obtaining annual Trinity River discharge rates, which are readily available from the USGS. Comparing DOC riverine inputs to benthic sources in Trinity Bay, measured directly on the same day, indicates that the sediments contribute approximately 20% of total inputs of DOC to Trinity Bay. However, assuming a constant benthic source during low-flow conditions, which can occur for periods of up to 14 months in this region of Texas, benthic fluxes would account for >80% of the total inputs into Trinity Bay. At high levels of discharge, the Trinity River discharges ~1.0 x 109 g C day-1 and dominates DOC inputs to Trinity Bayen_US
dc.description.urien_US
dc.historyen_US
dc.identifier.urihttp://hdl.handle.net/1969.3/23398
dc.latitudeen_US
dc.locationen_US
dc.longitudeen_US
dc.notesen_US
dc.placeen_US
dc.publisheren_US
dc.relation.ispartofseries51038.00en_US
dc.relation.urihttp://www.sciencedirect.com/science/article/B6V78-4C8P9HX-4/2/0af770df0964b1c1f69335538a1b9021en_US
dc.scaleen_US
dc.seriesen_US
dc.subjectGALVESTON-BAYen_US
dc.subjectTRACE-METALSen_US
dc.subjectMATTERen_US
dc.subjectTRANSPORTen_US
dc.subjectWATERSen_US
dc.subjectZNen_US
dc.subjectENVIRONMENTSen_US
dc.subjectEXCHANGEen_US
dc.subjectEXPORTen_US
dc.subjectOCEANen_US
dc.titleBiogeochemical behavior of organic carbon in the Trinity River downstream of a large reservoir lake in Texas, USAen_US
dc.typeJournalen_US
dc.universityen_US
dc.vol-issueIn Press, Corrected Proof()en_US

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