Freshwater-Saltwater Mixing Effects on Dissolved Carbon and CO2 Outgassing of a Coastal River Entering the Northern Gulf of Mexico

He, Songjie; Xu, Y. Jun

doi:10.1007/s12237-017-0320-4

Cited by 5 publications

(4 citation statements)

References 75 publications

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“…Our observations showed that DIC increased with salinity (Fig. 8a), a trend that differs from observations in Indian estuarine systems (Bouillon et al, 2003), but agrees with observations in several other systems such as in the US Gulf coast (He and Xu, 2018) and Madagascar (Ralison et al, 2008). Contrary to these studies, DIC minima observed here were much higher (around 1000 μmol L − 1 compared to < 500 μmol L − 1 ), which points to high bicarbonate (HCO −…”

Section: Dissolved Inorganic Carbon Inputs Sources and Processingsupporting

confidence: 88%

Carbon dynamics and CO2 and CH4 exchange in the mangrove dominated Guayas river delta, Ecuador

Belliard

Hernandez

Temmerman

et al. 2022

Estuarine, Coastal and Shelf Science

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Section: Dissolved Inorganic Carbon Inputs Sources and Processingsupporting

confidence: 88%

Carbon dynamics and CO2 and CH4 exchange in the mangrove dominated Guayas river delta, Ecuador

Belliard

Hernandez

Temmerman

et al. 2022

Estuarine, Coastal and Shelf Science

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“…The low concentration of bicarbonate recorded in the Negro River is likely linked to its high discharge, which is about ten and twenty times higher than those recorded in the Colorado and Chubut rivers, respectively. This trend is consistent with previous studies indicating that the inverse correlation between the inorganic carbon content and river discharge is because of a simple dilution effect controlled by the balance of precipitation and evaporation in the drainage basin (Cai et al 2016;He and Xu 2018).…”

Section: Environmental Variable Trendsupporting

confidence: 93%

Diatom-based inference model for conductivity reconstructions in dryland river systems from north Patagonia, Argentina

2021

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Dryland river systems support a diverse aquatic biota in semi-arid and arid landscapes, but they are increasingly vulnerable to natural and human impacts. This study provides the first modern diatom training set (n = 38) from three dryland rivers in northern Patagonia, Argentina. The relationship between surface-sediment diatoms and contemporary environmental variables was explored using multivariate analyses. The results showed that surface-water chemistry varies among rivers in accordance with local-scale factors such hydro-climatic variability and anthropic activities. A total of 378 diatom taxa were identified but only 45 taxa occurred with relative abundances higher than 2% in at least one sediment sample. The Colorado and Negro rivers were characterized by high abundances of small tychoplanktic fragilarioids whereas the Chubut River was dominated by epiphytic and planktic taxa. The canonical correspondence analyses (CCA) showed that conductivity, pH and HCO 3 − were the main environmental variables governing diatoms distributions. A transfer function was developed for water conductivity using unimodal methods because of partial CCA and λ 1 /λ 2 ratio revealed that this variable had the largest unique effect on diatom variance. A weighted averaging (WA) model with tolerance downweighting and classic deshrinking provided a reasonably robust model (r 2 jack = 0.94 and RMSEP = 0.249 log 10 μS cm −1 ). However, the diatom-inferred conductivity values should be carefully interpreted because of the uneven distribution of sampling sites and the dominance of small araphid diatoms belonging to the genera Staurosira, Pseudostaurosira and Punctastriata. By their benthic habitat, the distribution of these taxa could be influenced by other factors as light and substrate in addition to water chemistry. The autoecological information achieved through this study will provide the basis for a better insight into the hydrological responses of the dryland rivers in northern Patagonia to climate and environmental changes.

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“…The method detection limits for TP, DIP, and TSS were 0.01, 0.000279, and 4 mg L −1 , respectively. In addition to the data collected for this study, dissolved organic carbon (DOC) (data available in He and Xu 2017a and 2017b [28,29]) and total silicon (Si) concentrations in water samples collected during the same study period were processed, and results are included here where applicable.…”

Section: Field Measurements and Laboratory Analysismentioning

confidence: 99%

“…Because site 1 and the USGS discharge gage station at Kinder were about 40 km apart, we used an area weighting to estimate the runoff from the land between the two locations. Detailed calculations are available in He and Xu [29]. All discharge for the Calcasieu River presented in this study were the calculated discharge at site 1.…”

Section: Riverine Phosphorus Flux Calculationmentioning

confidence: 99%

Phosphorus Fluxes from Three Coastal Watersheds under Varied Agriculture Intensities to the Northern Gulf of Mexico

2018

Water

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This study aims to evaluate recent total phosphorus (TP) and dissolved inorganic phosphorus (DIP) transport from three coastal rivers-the Calcasieu, Mermentau, and Vermilion Rivers-that drain watersheds with varied agriculture intensities (21%, 67%, and 61%, respectively) into the northern Gulf of Mexico, one of the world's largest summer hypoxic zones. The study also examined the spatial trends of TP and DIP from freshwater to saltwater along an 88-km estuarine reach with salinity increasing from 0.02 to 29.50. The results showed that from 1990-2009 to 2010-2017, the TP fluxes for one of the agriculture-intensive rivers increased while no significant change was found for the other two rivers. Change in river discharge was the main reason for this TP flux trend. The two more agriculture-intensive river basins showed consistently higher TP and DIP concentrations and fluxes, as well as higher DIP:TP ratios than the river draining less agriculture-intensive land, confirming the strong effect of land uses on phosphorus input and speciation. Longitudinal profiles of DIP along the salinity gradient of the estuarine reach displayed characteristic input behavior. Desorption of DIP from suspended solids and river bed sediments, urban inputs, as well as stronger calcium carbonate and phosphorus co-precipitation at the marine endmember could be the reasons for such mixing dynamics.

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Freshwater-Saltwater Mixing Effects on Dissolved Carbon and CO2 Outgassing of a Coastal River Entering the Northern Gulf of Mexico

Cited by 5 publications

References 75 publications

Carbon dynamics and CO2 and CH4 exchange in the mangrove dominated Guayas river delta, Ecuador

Carbon dynamics and CO2 and CH4 exchange in the mangrove dominated Guayas river delta, Ecuador

Diatom-based inference model for conductivity reconstructions in dryland river systems from north Patagonia, Argentina

Phosphorus Fluxes from Three Coastal Watersheds under Varied Agriculture Intensities to the Northern Gulf of Mexico

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