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Full-Text Articles in Physical Sciences and Mathematics
Photochemical And Microbial Alteration Of Dissolved Organic Matter In Temperate Headwater Streams Associated With Different Land Use, Yuehan Lu, James E. Bauer, Elizabeth A. Canuel, Youhei Yamashita, R. M. Chambers, Rudolf Jaffe´
Photochemical And Microbial Alteration Of Dissolved Organic Matter In Temperate Headwater Streams Associated With Different Land Use, Yuehan Lu, James E. Bauer, Elizabeth A. Canuel, Youhei Yamashita, R. M. Chambers, Rudolf Jaffe´
FCE LTER Journal Articles
[1] Photochemical and microbial transformations of DOM were evaluated in headwater streams draining forested and human-modified lands (pasture, cropland, and urban development) by laboratory incubations. Changes in DOC concentrations, DOC isotopic signatures, and DOM fluorescence properties were measured to assess the amounts, sources, ages, and properties of reactive and refractory DOM under the influence of photochemistry and/or bacteria. DOC in streams draining forest-dominated watersheds was more photoreactive than in streams draining mostly human-modified watersheds, possibly due to greater contributions of terrestrial plant-derived DOC and lower amounts of prior light exposure in forested streams. Overall, the percentage of photoreactive DOC in …
Flux Of Organic Carbon In A Riverine Mangrove Wetland In The Florida Coastal Everglades, Melissa M. Romigh, Stephen E. Davis Iii, Victor H. Rivera-Monroy, Robert R. Twilley
Flux Of Organic Carbon In A Riverine Mangrove Wetland In The Florida Coastal Everglades, Melissa M. Romigh, Stephen E. Davis Iii, Victor H. Rivera-Monroy, Robert R. Twilley
FCE LTER Journal Articles
Short-term (daily) and seasonal variations in concentration and flux of dissolved organic carbon (DOC) were examined over 15 tidal cycles in a riverine mangrove wetland along Shark River, Florida in 2003. Due to the influence of seasonal rainfall and wind patterns on Shark River’s hydrology, samplings were made to include wet, dry and transitional (Norte) seasons. We used a flume extending from a tidal creek to a basin forest to measure vertical (vegetated soil/water column) and horizontal (mangrove forest/tidal creek) flux of DOC. We found significant (p < 0.05) variations in surface water temperature, salinity, conductivity, pH and mean concentration of DOC with season. Water temperature and salinity followed seasonal patterns of air temperature and rainfall, while mean DOC concentration was highest during the dry season (May), followed by the wet (October) and ‘Norte’ (December) seasons. This pattern of DOC concentration may be due to a combination of litter production and inundation pattern of the wetland. In contrast to daily (between tides) variation in DOC flux between the mangrove forest and tidal creek, daily variations of mean water quality were not significant. However, within-tide variation of DOC flux, dissolved oxygen content and salinity was observed. This indicated that the length of inundation and water source (freshwater vs. saltwater) variation across tidal cycles influenced water quality and DOC flux in the water column. Net DOC export was measured in October and December, suggesting the mangrove forest was a source of DOC to the adjacent tidal creek during these periods. Net annual export of DOC from the fringe mangrove to both the tidal creek and basin mangrove forest was 56 g C m−2 year−1. The seasonal pattern in our flux results indicates …