The dissolution kinetics and apparent solubility of natural apatite in closed reactors at temperatures from 5 to 50 °C and pH from 1 to 6

Harouiya, Najatte; Chaïrat, Claire; Köhler, Stephan Jürgen; Gout, Robert; Oelkers, Eric H.

doi:10.1016/j.chemgeo.2007.07.011

Cited by 88 publications

(46 citation statements)

References 37 publications

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“…Measured aqueous Mg concentrations were fitted following the method described by Harouiya et al (2007) using equation 4 and a trial-and-error method by varying k Hmg and comparing fluid concentrations calculated using an EXCEL spread sheet with measured aqueous Mg concentrations. The results of this fit for all experiments are shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

The experimental determination of hydromagnesite precipitation rates at 22.5–75ºC

Berninger

Jordan²,

Schott

et al. 2014

Mineral. mag.

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Natural hydromagnesite (Mg 5 (CO 3 ) 4 (OH) 2 ·4H 2 O) dissolution and precipitation experiments were performed in closed-system reactors as a function of temperature from 22.5 to 75ºC and at 8.6 < pH < 10.7. The equilibrium constants for the reaction Mg 5 (CO 3 ) 4 (OH) 2 ·4H 2 O + 6H + = 5Mg 2+ + 4HCO 3 À + 6H 2 O were determined by bracketing the final fluid compositions obtained from the dissolution and precipitation experiments. The resulting constants were found to be 10 33.7Ô0.9 , 10 30.5Ô0.5 and 10 26.5Ô0.5at 22.5, 50 and 75ºC, respectively. Whereas dissolution rates were too fast to be determined from the experiments, precipitation rates were slower and quantified. The resulting BET surface areanormalized hydromagnesite precipitation rates increase by a factor of~2 with pH decreasing from 10.7 to 8.6. Measured rates are approximately two orders of magnitude faster than corresponding forsterite dissolution rates, suggesting that the overall rates of the low-temperature carbonation of olivine are controlled by the relatively sluggish dissolution of the magnesium silicate mineral.

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Section: Resultsmentioning

confidence: 99%

The experimental determination of hydromagnesite precipitation rates at 22.5–75ºC

Berninger

Jordan²,

Schott

et al. 2014

Mineral. mag.

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“…Figure 9 also shows that highest terrestrial CFA contents in marine sediments were reported from permanently arid and/or cold regions with dominantly physical weathering (e.g., deserts or polar latitudes) (Eijsink et al, 2000;Flaum, 2008;Anderson et al, 2010;Furutani et al, 2010;Zhang et al, 2010;Kraal et al, 2012). This seems logical, as prolonged chemical weathering under humid conditions creates acidic soils (e.g., peat bogs, tropical soils), leading to partial dissolution of CFA in the terrestrial environment (Walker and Syers, 1976;Smeck, 1985;Guidry andMackenzie, 2000, 2003;Le Roux et al, 2006;Harouiya et al, 2007). In open marine regions beyond the immediate influence of river-borne CFA, the deposition of eolian CFA certainly plays a significant role, especially within the Northern Hemisphere "dust belt" between ~10 and ~60°N (Prospero et al, 2002;Maher et al, 2010).…”

Section: Terrigenous Cfa Opal-bound P and The Marine Reactive P Budgetmentioning

confidence: 99%

“…However, CFA eroded from sedimentary rocks on land would not dissolve under normal marine pH and temperature conditions ( Fig. 8) (Guidry and Mackenzie, 2003;Carbo et al, 2005;Harouiya et al, 2007;Anderson et al, 2010;Furutani et al, 2010;Savenko, 2010), and should therefore be treated as non-reactive. Defining the CFA fraction as being exclusively derived from the reactive P pool would lead to an overestimation of reactive P burial rates (Compton et al, 2000;Ruttenberg, 2003;Kraal et al, 2012).…”

Section: Terrigenous Cfa Opal-bound P and The Marine Reactive P Budgetmentioning

confidence: 99%

Phosphorus burial and diagenesis in the central Bering Sea (Bowers Ridge, IODP Site U1341): Perspectives on the marine P cycle

et al. 2014

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To reconstruct the cycling of reactive phosphorus (P) in the Bering Sea, a P speciation record covering the last ~4 Ma was generated from sediments recovered during Integrated Ocean Drilling Program (IODP) Expedition 323 at Site U1341 (Bowers Ridge). A chemical extraction procedure distinguishing between different operationally defined P fractions provides new insight into reactive P input, burial and diagenetic transformations. Reactive P mass accumulation rates (MARs) are ~20-110 µmol/cm 2 /ka, which is comparable to other open ocean locations but orders of magnitude lower than most upwelling settings. We find that authigenic carbonate fluorapatite (CFA) and opal-bound P are the dominant P fractions at Site U1341. An overall increasing contribution of CFA to total P with sediment depth is consistent with a gradual "sink switching" from more labile P fractions (fish remains, Fe oxides, organic matter) to stable authigenic CFA. However, the positive correlation of CFA with Al content implies that a significant portion of the supposedly reactive CFA is non-reactive "detrital contamination" by eolian and/or riverine CFA. In contrast to CFA, opal-bound P has rarely been studied in marine sediments. We find for the first time that opal-bound P directly correlates with excess silica contents. This P fraction was apparently available to biosiliceous phytoplankton at the time of sediment deposition and is a long-term sink for reactive P in the ocean, despite the likelihood for diagenetic re-mobilisation of this P at depth (indicated by increasing ratios of excess silica to opal-bound P). Average reactive P MARs at Site U1341 increase by ~25% if opal-bound P is accounted for, but decrease by ~25% if 50% of the extracted CFA fraction (based on the lowest CFA value at Site U1341) is assumed to be detrital. Combining our results with literature data, we present a qualitative perspective of terrestrial CFA and opal-bound P deposition in the modern ocean.Riverine CFA input has mostly been reported from continental shelves and margins draining P-rich lithologies, while eolian CFA input is found across wide ocean regions underlying the Northern Hemispheric "dust belt". Opal-bound P burial is important in the Southern Ocean, North Pacific, and likely in upwelling areas. Shifts in detrital CFA and opal-bound P deposition across ocean basins likely occurred over time, responding to changing weathering patterns, sea level, and biogenic opal deposition.Keywords: Integrated Ocean Drilling Program, Bering Sea, phosphorus, sequential extraction, biogenic opal, carbonate fluorapatite. IntroductionPhosphorus is a key biolimiting nutrient that exerts a major control on marine primary productivity over geological -and potentially shorter -time scales (Redfield, 1958;Codispoti, 1989;Krom et al., 1991;Van Cappellen and Ingall, 1996;Cotner et al., 1997;Tyrell, 1999;Benitez-Nelson, 2000;Filippelli, 2008). Marine productivity in the photic zone is, in turn, a key factor for the photosynthetic sequestration of the greenhouse gas CO 2 in...

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“…doi:10. 1016/j.gca.2010.10.012 precipitation rates of apatite (Christoffersen et al, 1998;Valsami-Jones et al, 1998;Welch et al, 2002;Guidry and MacKenzie, 2003;Kö hler et al, 2005a;Goyne et al, 2006;Chaïrat et al, 2007;Harouiya et al, 2007), monazite (Oelkers and Poitrasson, 2002;Seydoux-Guillaume et al, 2002;Poitrasson et al, 2004), vivianite (Thinnappan et al, 2008), britholite (Chaïrat et al, 2006;Kamel et al, 2007), strengite (Petticrew and Arocena, 2001), and struvite (Battistoni et al, 1997;Doyle and Parsons, 2002;Le Corre et al, 2007). To date no measurement of variscite dissolution rates have been reported in the literature.…”

Section: Introductionmentioning

confidence: 95%

Does variscite control phosphate availability in acidic natural waters? An experimental study of variscite dissolution rates

Roncal-Herrero¹,

Oelkers²

2011

Geochimica et Cosmochimica Acta

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The dissolution kinetics and apparent solubility of natural apatite in closed reactors at temperatures from 5 to 50 °C and pH from 1 to 6

Cited by 88 publications

References 37 publications

The experimental determination of hydromagnesite precipitation rates at 22.5–75ºC

The experimental determination of hydromagnesite precipitation rates at 22.5–75ºC

Phosphorus burial and diagenesis in the central Bering Sea (Bowers Ridge, IODP Site U1341): Perspectives on the marine P cycle

Does variscite control phosphate availability in acidic natural waters? An experimental study of variscite dissolution rates

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