Stable isotopic composition of Holocene benthic foraminifers from the Eastern Mediterranean Sea: Past changes in productivity and deep water oxygenation

Kuhnt, Tanja; Schmiedl, Gerhard; Ehrmann, Werner; Hamann, Yvonne; Andersen, Nils

doi:10.1016/j.palaeo.2008.07.010

Cited by 55 publications

(37 citation statements)

References 65 publications

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“…Wetter conditions also seem evident in the North Aegean sub-region around 4500 yrs BP, preceded and succeeded by drier conditions (Kuhnt et al, , 2008. The succeeding dry period concurs with a period of altered minerogenic composition of the ocean sediments, possibly indicating an abrupt climatic change in the North Aegean catchment at 4400 yrs BP Kuhnt et al, 2007).…”

Section: Humiditymentioning

confidence: 76%

Climate in the eastern Mediterranean, and adjacent regions, during the past 6000 years – A review

Finné

Holmgren

Sundqvist

et al. 2011

Journal of Archaeological Science

271

180

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Section: Humiditymentioning

confidence: 76%

Climate in the eastern Mediterranean, and adjacent regions, during the past 6000 years – A review

Finné

Holmgren

Sundqvist

et al. 2011

Journal of Archaeological Science

271

180

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“…Faunal and stable isotope records from benthic foraminifera located at intermediate depths in the eastern basin reveal well-ventilated LIW during the last glacial period and deglaciation (Kuhnt et al, 2008;Schmiedl et al, 2010). Similarly, a grain-size record obtained from a sediment core collected within the LIW depth range (∼ 500 m water depth) at the eastern Corsica margin also documents enhanced bottom currents during the glacial period and for specific time intervals of the deglaciation, such as HS1 and YD (Toucanne et al, 2012).…”

Section: Introductionmentioning

confidence: 73%

“…Similarly, a grain-size record obtained from a sediment core collected within the LIW depth range (∼ 500 m water depth) at the eastern Corsica margin also documents enhanced bottom currents during the glacial period and for specific time intervals of the deglaciation, such as HS1 and YD (Toucanne et al, 2012). The Early Holocene is characterized by a collapse of the LIW (Kuhnt et al, 2008;Schmiedl et al, 2010;Toucanne et al, 2012) synchronous with the sapropel S1 deposition (10.2-6.4 cal ka BP; Mercone et al, 2000). Proxies for deep-water conditions reveal the occurrence of episodes of deep-water overturning reinforcement in the eastern Mediterranean basin at 8.2 ka BP (Rohling et al, 1997(Rohling et al, , 2015Kuhnt et al, 2007;Abu-Zied et al, 20082015), responsible for the interruption of the sapropel S1 in the eastern Mediterranean basin (Mercone et al, 2001;Rohling et al, 2015).…”

Section: Introductionmentioning

confidence: 75%

Hydrological variations of the intermediate water masses of the western Mediterranean Sea during the past 20 ka inferred from neodymium isotopic composition in foraminifera and cold-water corals

et al. 2017

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Abstract. We present the neodymium isotopic composition (εNd) of mixed planktonic foraminifera species from a sediment core collected at 622 m water depth in the Balearic Sea, as well as εNd of scleractinian cold-water corals (CWC; Madrepora oculata, Lophelia pertusa) retrieved between 280 and 442 m water depth in the Alboran Sea and at 414 m depth in the southern Sardinian continental margin. The aim is to constrain hydrological variations at intermediate depths in the western Mediterranean Sea during the last 20 kyr. Planktonic (Globigerina bulloides) and benthic (Cibicidoides pachyderma) foraminifera from the Balearic Sea were also analyzed for stable oxygen (δ 18 O) and carbon (δ 13 C) isotopes. The foraminiferal and coral εNd values from the Balearic and Alboran seas are comparable over the last ∼ 13 kyr, with mean values of −8.94 ± 0.26 (1σ ; n = 24) and −8.91 ± 0.18 (1σ ; n = 25), respectively. Before 13 ka BP, the foraminiferal εNd values are slightly lower (−9.28 ± 0.15) and tend to reflect higher mixing between intermediate and deep waters, which are characterized by more unradiogenic εNd values. The slight εNd increase after 13 ka BP is associated with a decoupling in the benthic foraminiferal δ 13 C composition between intermediate and deeper depths, which started at ∼ 16 ka BP. This suggests an earlier stratification of the water masses and a subsequent reduced contribution of unradiogenic εNd from deep waters. The CWC from the Sardinia Channel show a much larger scatter of εNd values, from −8.66 ± 0.30 to −5.99 ± 0.50, and a lower average (−7.31 ± 0.73; n = 19) compared to the CWC and foraminifera from the Alboran and Balearic seas, indicative of intermediate waters sourced from the Levantine basin. At the time of sapropel S1 deposition (10.2 to 6.4 ka), the εNd values of the Sardinian CWC become more unradiogenic (−8.38 ± 0.47; n = 3 at ∼ 8.7 ka BP), suggesting a significant contribution of intermediate waters originated from the western basin. We propose that western Mediterranean intermediate waters replaced the Levantine Intermediate WaPublished by Copernicus Publications on behalf of the European Geosciences Union. ter (LIW), and thus there was a strong reduction of the LIW during the mid-sapropel (∼ 8.7 ka BP). This observation supports a notable change of Mediterranean circulation pattern centered on sapropel S1 that needs further investigation to be confirmed.

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“…In fact, sapropels respond to periods of enhanced freshwater flux (e.g., Rohling and Hilgen 1991;Bar-Matthews et al 2000;Kallel et al 2000) during periods of strong summer insolation (e.g., Rohling 1994;Rohling et al 2002;Meyers 2006). Evidence from eastern Mediterranean Quaternary sapropel studies indicate that freshwater stratification and organic carbon accumulation took place due to both enhanced productivity and hypoxia, during warm and wet climatic conditions (e.g., De Lange and Ten Haven 1983;Emeis et al 2000a;Casford et al 2003;Gogou et al 2007;De Lange et al 2008;Kuhnt et al 2008;Triantaphyllou et al 2009aTriantaphyllou et al , b, 2010Triantaphyllou et al , 2013Katsouras et al 2010;Schmiedl et al 2010;Kouli et al 2012;Triantaphyllou 2014).…”

Section: Introductionmentioning

confidence: 99%

Zanclean/Piacenzian transition on Cyprus (SE Mediterranean): calcareous nannofossil evidence of sapropel formation

et al. 2015

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Quantitative analyses of calcareous nannofossils in the sediments of Pissouri South section on the island of Cyprus have produced a paleoceanographic record reflecting the paleoclimatic conditions during the Zanclean/Piacenzian transition. Pissouri South cyclical lithological alternations between organic-rich laminated layers and grey marls reflect the Earth's orbital precession. According to the calcareous nannofossil biostratigraphy which has been performed, the studied section is correlated with MNN14/15 and MNN16 calcareous nannofossil biozones and is astronomically dated between 4.065 and 3.217 Ma. Intervals of increased organic carbon content, along with the positive values of Florisphaera profunda, Helicosphaera sellii, Discoaster spp. and the subsequent increase of stratification S-index, correspond to the sapropel deposition during periods of wetter climate and intense continental runoff, especially from the river Nile. These layers alternate with grey marly intervals, featured by the increased values of small placoliths of Reticulofenestra and Gephyrocapsa species, which are indicative of eutrophic conditions during intense surface-water mixing. Our data support the prevalence of a generally warm phase characterized by the absence of high-frequency climate variations in the southeastern Mediterranean during the Zanclean/Piacenzian (Early/Late Pliocene) transition.

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Stable isotopic composition of Holocene benthic foraminifers from the Eastern Mediterranean Sea: Past changes in productivity and deep water oxygenation

Cited by 55 publications

References 65 publications

Climate in the eastern Mediterranean, and adjacent regions, during the past 6000 years – A review

Climate in the eastern Mediterranean, and adjacent regions, during the past 6000 years – A review

Hydrological variations of the intermediate water masses of the western Mediterranean Sea during the past 20 ka inferred from neodymium isotopic composition in foraminifera and cold-water corals

Zanclean/Piacenzian transition on Cyprus (SE Mediterranean): calcareous nannofossil evidence of sapropel formation

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Stable isotopic composition of Holocene benthic foraminifers from the Eastern Mediterranean Sea: Past changes in productivity and deep water oxygenation

Cited by 55 publications

References 65 publications

Climate in the eastern Mediterranean, and adjacent regions, during the past 6000 years – A review

Climate in the eastern Mediterranean, and adjacent regions, during the past 6000 years – A review

Hydrological variations of the intermediate water masses of the western Mediterranean Sea during the past 20 ka inferred from neodymium isotopic composition in foraminifera and cold-water corals

Zanclean/Piacenzian transition on Cyprus (SE Mediterranean): calcareous nannofossil evidence of sapropel formation

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Hydrological variations of the intermediate water masses of the western Mediterranean Sea during the past 20 ka inferred from neodymium isotopic composition in foraminifera and cold-water corals