Controls on phosphorus regeneration and burial during formation of eastern Mediterranean sapropels

Slomp, Caroline P.; Thomson, J.; Lange, Gert J. de

doi:10.1016/s0025-3227(03)00335-9

Cited by 116 publications

(78 citation statements)

References 73 publications

(127 reference statements)

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“…The measured C org /P org molar ratios deviate from the Redfield ratio (106:1; Redfield, 1958), which implies that the preserved organic matter is depleted in phosphorus relative to carbon. Ingall et al (1993), Jahnke (1994, 1997), Van Cappellen and Ingall (1996), and Slomp et al (2004) associated increased C org /P org molar ratios in organic matter with the degradation of organic matter and the relative loss of organic phosphorus under the influence of water column anoxia, which would concur with the overall minimal values in P accumulation rates during the Faraoni anoxic event. Interestingly, a twofold spike in C org /P org molar ratio is present in both sections, which may suggest that the unfolding of anoxic conditions may not have been uniform, but stepwise, with an intermittent return to more normal conditions.…”

Section: The C/p Molar Ratiomentioning

confidence: 80%

The late Hauterivian Faraoni oceanic anoxic event in the western Tethys: Evidence from phosphorus burial rates

Bodin

Godet

Föllmi

et al. 2006

Palaeogeography, Palaeoclimatology, Palaeoecology

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In the uppermost Hauterivian sediments of the western Tethys, a short-lived anoxic event (Faraoni event) is documented both in the form of an interval enriched in organic matter (pelagic realm) and in a condensed interval enriched in glauconite and phosphate (shelf realm). This latter interval represents the onset of a drowning episode on the Helvetic carbonate platform along the northern tethyan margin that lasted throughout the early Barremian. This drowning episode marks a turning point in the way the platform carbonate factory functioned: during the Hauterivian carbonate production was dominated by heterozoans, whereas during the late Barremian a photozoan assemblage developed that is preserved in the so-called Urgonian limestone. The late Hauterivian Faraoni oceanic anoxic event is of particular interest because it is not accompanied by a major positive shift in y 13 C unlike other oceanic anoxic events during the Cretaceous (Valanginian, early Aptian, Cenomanian-Turonian boundary).We have analyzed four (hemi-)pelagic sections with regards to their phosphorus content to better understand the palaeoceanographic conditions related to this anoxic event and the associated changes in the shallow-water carbonate factory. The sections are located in Angles (SE France), Fiume-Bosso and Gorgo a Cerbara (central Italy), and Veveyse de Châtel-St. Denis (west Switzerland). We calculated phosphorus mass accumulation rates by using a cyclostratigraphic approach in order to obtain an adequate age model. We observe a comparable and correlatable long-term trend for the four sections, which suggests that the phosphorus mass accumulation rates and temporal changes therein are representative for the western tethyan pelagic realm. The Faraoni event is marked by a minimum in phosphorus accumulation and a positive shift in the C org /P tot ratios, which is interpreted as a reflection of the decreased capacity of storing and preserving phosphorus in oxygen-depleted sediments. Moreover, the onset in the decrease in phosphorus accumulation coincides with a sea level rise, while the Faraoni level itself corresponds to a maximum flooding interval. This phase of sea-level rise may have been important in the establishment of marine connections between the boreal and tethyan realms and, as such, in the exchange of nutrient-enriched waters. The model for the origin of the Faraoni oceanic anoxic event proposed here incorporates these aspects together with a positive feedback loop generated by phosphorus regeneration and a negative feedback loop related to changes in the ocean oxygen cycle.The subsequent long-term changes in phosphorus burial rates during the Barremian suggest that the Faraoni event marks the onset of a long period of environmental instability with regards to platform growth, leading to periodic phases of eutrophication * Corresponding author. Tel.: +41 32 718 26 05; fax: +41 32 718 26 01.E-mail address: stephane.bodin@unine.ch (S. Bodin).and drowning of the northern tethyan carbonate platform. This environmental cr...

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Section: The C/p Molar Ratiomentioning

confidence: 80%

The late Hauterivian Faraoni oceanic anoxic event in the western Tethys: Evidence from phosphorus burial rates

Bodin

Godet

Föllmi

et al. 2006

Palaeogeography, Palaeoclimatology, Palaeoecology

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“…To support their idea, they simulated the effects of sediment mixing on phosphorus and organic carbon burial in a simplified model of global biogeochemistry. In their simulations, bioturbated sediments retain more phosphorus relative to carbon as compared to unmixed sediments, a signature also observed in present day bioturbated sediments 8 . Higher organic phosphorus burial lowers the availability of the limiting nutrient phosphorus, and hence decreases oceanic productivity, which leads to reduced organic carbon burial and lower oceanic and atmospheric O2 concentrations.…”

Section: Filip J R Meysmanmentioning

confidence: 70%

Oxygen burrowed away

Meysman

2014

Nature Geosci

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“…CDB-P and CDB-Fe show a peak at the top of S1, and not above the visual sapropel, as it was expected (Slomp et al, 2002(Slomp et al, , 2004. This is probably due to the presence of well-crystallized Fe oxides in the oxidized sapropel (Slomp et al, 1996) that are a less efficient sink for phosphorus in comparison with amorphous phases.…”

Section: Phosphorus Phases and C/p Ratiosmentioning

confidence: 72%

“…The observed Fe enrichment can then be attributed to dissolution of amorphous Fe sulfides during the CDB step of the sequential extraction (Slomp et al, 1996). Both CDB-P and CDB-Fe curves, however, resemble closely the distribution shown by Slomp et al (2002Slomp et al ( , 2004 suggesting that these peaks could anyway be related to the redox front.…”

Section: Phosphorus Phases and C/p Ratiosmentioning

confidence: 87%

Geochemical evidence for high-resolution variations during deposition of the Holocene S1 sapropel on the Cretan Ridge, Eastern Mediterranean

Gennari

Tamburini

Ariztegui

et al. 2009

Palaeogeography, Palaeoclimatology, Palaeoecology

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Major and minor element distributions and solid phase phosphorus contents were measured in a sediment core from the Cretan Ridge that contains the Holocene S1 sapropel. Micro-XRF ultra-high resolution analysis reveals multiple Mn peaks in the oxidized upper portion of the sapropel, which implies either a non-steadystate upward remobilization of Mn or not constant downward diffusion of bottom water oxygen. Sequential extraction allowed the identification of different phosphorus phases. Detrital phosphorus increases in the sapropel layer, suggesting enhanced delivery from land during sapropel deposition. Higher organic carbon to organic phosphorus ratios in the sapropel indicate enhanced regeneration of phosphorus relative to carbon under low-oxygen conditions. Fourier analysis on the ultra-high resolution XRF data reveals frequencies that are provisionally assigned to millennial to decennial solar cycles. Although these cycles have been reported from several continental and marine archives, they have never been documented from Sapropel S1 in the Eastern Mediterranean.

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Controls on phosphorus regeneration and burial during formation of eastern Mediterranean sapropels

Cited by 116 publications

References 73 publications

The late Hauterivian Faraoni oceanic anoxic event in the western Tethys: Evidence from phosphorus burial rates

The late Hauterivian Faraoni oceanic anoxic event in the western Tethys: Evidence from phosphorus burial rates

Oxygen burrowed away

Geochemical evidence for high-resolution variations during deposition of the Holocene S1 sapropel on the Cretan Ridge, Eastern Mediterranean

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