The Behaviour of Dissolved Barium in Estuaries

Coffey, M. T.; Dehairs, Frank; Collette, Olivier; Luther, George W.; Church, Thomas M.; Jickells, Timothy D.

doi:10.1006/ecss.1996.0157

Cited by 243 publications

(184 citation statements)

References 16 publications

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“…The concentration of dissolved barium (Ba) in rivers varies as a function of basin lithology, geometry, and rate of runoff, and can range from~100 to 600 nmol l À1 (Coffey et al, 1997). Conversely, [Ba] is very low (e.g.,~33e40 nmol l À1 ) in the open ocean (Lea and Boyle, 1991;Lea and Spero, 1994).…”

Section: Planktic Foraminifer Ecology and Geochemistrymentioning

confidence: 99%

“…The concentration of fluvialderived Ba in estuarine mixing zones increases during mixing at low salinities (5e15 psu (practical salinity units)), as barium desorbs from suspended particulate matter, up to 350e500 nmol l À1 (Coffey et al, 1997;Hanor and Chan, 1977). The behavior of Ba at low, estuarine salinities is non-conservative, but conservative mixing of Ba between brackish estuarine salinities and open marine waters is observed at salinities >15 psu (Coffey et al, 1997;Guay and Falkner, 1997). The Ba/Ca ratio of seawater can therefore be used to quantify salinities >15e20 psu.…”

Section: Planktic Foraminifer Ecology and Geochemistrymentioning

confidence: 99%

“…(3) for data points with S > 15 psu, to avoid the nonconservative mixing behavior of Ba at estuarine salinities <15 psu (Coffey et al, 1997;Hanor and Chan, 1977). The resulting local salinity-Ba/Ca shell relationship (Fig.…”

Section: Planktic Foraminifer Ecology and Geochemistrymentioning

confidence: 99%

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Oxygen isotope geochemistry of Laurentide ice-sheet meltwater across Termination I

Vetter

Spero

Eggins

et al. 2017

Quaternary Science Reviews

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a b s t r a c tWe present a new method that quantifies the oxygen isotope geochemistry of Laurentide ice-sheet (LIS) meltwater across the last deglaciation, and reconstruct decadal-scale variations in the d 18 O of LIS meltwater entering the Gulf of Mexico between~18 and 11 ka. We employ a technique that combines laser ablation ICP-MS (LA-ICP-MS) and oxygen isotope analyses on individual shells of the planktic values of Mississippi River discharge from discrete core intervals range from À22‰ to À38‰ VSMOW. These values suggest a dynamic melting history of different parts of the LIS, with potential contributions to Mississippi River outflow from both the low-elevation, southern margin of the LIS and high-elevation, high-latitude domes in the LIS interior that were transported to the ablation zone. Prior to~15.5 ka, the d 18 O water value of the Mississippi River was similar to that of regional precipitation or low-latitude LIS meltwater, but the Ba concentration in the Mississippi basin was affected by changes in weathering within the watershed, complicating Ba-salinity relationships in the Gulf of Mexico. After 13 ka, our data suggest Mississippi River outflow did not influence surface salinity above our Gulf of Mexico Orca Basin core site. Rather, we hypothesize that open ocean conditions prevailed as sea level rose and the paleoshoreline at the southern edge of North America retreated northward.

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Section: Planktic Foraminifer Ecology and Geochemistrymentioning

confidence: 99%

Section: Planktic Foraminifer Ecology and Geochemistrymentioning

confidence: 99%

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Oxygen isotope geochemistry of Laurentide ice-sheet meltwater across Termination I

Vetter

Spero

Eggins

et al. 2017

Quaternary Science Reviews

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“…As Ba substitutes Ca in the coral skeleton, sediment discharge is reconstructed accordingly using skeletal Ba / Ca ratios (Sinclair and McCulloch, 2004;Alibert et al, 2003;McCulloch et al, 2003;Fleitmann et al, 2007). However, as estuarine processes, such as phytoplankton uptake and resuspension, can lead to a nonconservative behaviour of Ba (Hanor and Chan, 1977;Coffey et al, 1997); subsequently, sediment discharge reconstructions can be affected (Sinclair, 2005). In such circumstances, skeletal Ba / Ca levels may not be directly related to sediment discharge.…”

Section: A Grove Et Al: Spatial Linkages Between Coral Proxies Omentioning

confidence: 99%

“…1), the high concentrations of HA associated with each watershed and the conservative mixing nature of HA (Bowers and Brett, 2008). Unlike HA, barium behaves non-conservatively in estuaries, as it is influenced by processes such as phytoplankton cycling (Sinclair, 2005;Hanor and Chan, 1977;Coffey et al, 1997). Therefore, the riverine Ba signal associated with MAS1 may well have diminished by the time it reached coral ANDRA.…”

Section: Spatial Linkages Between Coral Proxies Of Terrestrial Runoffmentioning

confidence: 99%

Spatial linkages between coral proxies of terrestrial runoff across a large embayment in Madagascar

et al. 2012

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Abstract. Coral cores provide vital climate reconstructions for site-specific temporal variability in river flow and sediment load. Yet, their ability to record spatial differences across multiple catchments is relatively unknown. Here, we investigate spatial linkages between four coral proxies of terrestrial runoff and their relationships between sites. Coral cores were drilled in and around Antongil Bay, the largest bay in Madagascar, and individually analysed for fifteen years of continuous luminescence (G / B), Ba / Ca, δ 18 O sw and δ 13 C data. Each coral core was drilled close to individual river mouths (≤ 7 km), and proxy data were compared to modelled river discharge and sediment runoff data for the three corresponding catchments. A reasonable agreement between terrestrial runoff proxies with modelled river discharge and sediment yield was observed. Some inconsistencies between proxy and modelled data are likely linked to proxy behaviour, watershed size and local environmental physiochemical parameters. In general, the further a coral resided from its river source, the weaker the proxy relationship was with modelled data and other corals, due to mixing gradients and currents. Nevertheless, we demonstrate that two coral Ba / Ca and luminescence (G / B) records influenced by the same watershed are reproducible. Furthermore, a strong Ba / Ca relationship was observed between two cores from distant watersheds, with baseline averages in agreement with modelled sediment runoff data. As humic acids behave conservatively in the water column, luminescence (G / B) data gave the highest regional correlations between cores, and showed the most consistent relationship with site specific modelled discharge. No statistical relationship was observed between cores in terms of interannual δ 18 O sw and δ 13 C, meaning corals were recording a localised signal at their respective sites, confounded by vital effects. Comparing proxy baseline averages and mean seasonal cycles provided a good overview of the runoff dynamics of the bay system.

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LA‐ICPMS Ba/Ca analyses of planktic foraminifera from the Bay of Bengal: Implications for late Pleistocene orbital control on monsoon freshwater flux

Evans

Bhatia

Stoll

et al. 2015

Geochem Geophys Geosyst

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Indian Summer Monsoon (ISM) indices are characterized by large secular variation during both glacials and interglacials. Although much information about palaeomonsoon intensity is derived from such indicies, current data sets do not relate simply to precipitation. In order to directly constrain the variability of ISM freshwater flux to the Bay of Bengal, we report Ba/Ca LA-ICPMS data of the surface-dwelling foraminifera Globigerinoides ruber from core RC12-343 (central Bay of Bengal) between 68 and 47 ka. Planktic foraminifera Ba/Ca directly relates to seawater Ba/Ca, in turn principally controlled by freshwater flux. Our foraminifera-derived Ba=Ca sw record for the central Bay of Bengal is highly coherent with that derived from d18 O measurements of the same material, implying that these reconstructions are not significantly biased by potential shifts in d 18 O freshwater . Validating this method allows us to produce a freshwater stack for the last 80 ka for the Bay of Bengal, enabling the orbital controls on ISM precipitation to be examined for the first time. The highest freshwater flux in the last 80 ka was 3X larger than present and occurred during the early-mid Holocene. We show that the orbital timing of this record is best explained by a combination of factors with a weighting of 45% given to the 308N-equator mean summer insolation gradient and 55% given to the variability of May-July insolation at the equator and June-July insolation at 308N. These processes are consistent with current mechanistic understanding of ISM forcings and demonstrate a dominant orbital control on monsoon precipitation amount on millennial timescales.

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The Behaviour of Dissolved Barium in Estuaries

Cited by 243 publications

References 16 publications

Oxygen isotope geochemistry of Laurentide ice-sheet meltwater across Termination I

Oxygen isotope geochemistry of Laurentide ice-sheet meltwater across Termination I

Spatial linkages between coral proxies of terrestrial runoff across a large embayment in Madagascar

LA‐ICPMS Ba/Ca analyses of planktic foraminifera from the Bay of Bengal: Implications for late Pleistocene orbital control on monsoon freshwater flux

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