Florisphaera profunda, a possible nannoplankton indicator of late Quaternary changes in sea-water turbidity at the northwestern margin of the Pacific

Ahagon, Naokazu; Tanaka, Yuichiro; Ujiié, Hiroshi

doi:10.1016/0377-8398(93)90047-2

Cited by 137 publications

(73 citation statements)

References 13 publications

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“…However, we must keep in mind that the present ecological requirements of F. profunda are not unambiguously known. In fact, Ahagon et al (1993) recognized a close relationship between the increase of F. profunda abundance and increased water-transparency. In contrast, in modern coccolithophore assemblages F. profunda increases during the cold season (January-February) when coccolithophorids bloom (Ziveri et al, 1995a), thus it appears to prefer nutrient depleted water characterized also by low light intensity and low temperature.…”

Section: Discussionmentioning

confidence: 94%

Calcareous nannofossil biostratigraphy of the M. del Casino section (northern Apennines, Italy) and paleoceanographic conditions at times of Late Miocene sapropel formation

Negri

Giunta

Hilgen

et al. 1999

Marine Micropaleontology

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A detailed quantitative calcareous nannofossil analysis has been performed on 138 samples from the astronomically dated Monte del Casino section with the aim to identify and precisely date the most important calcareous nannofossil events across the Tortonian=Messinian boundary in the Mediterranean, and to unravel paleoceanographic conditions at times of sapropel formation during the Late Miocene. From the biostratigraphic perspective, the genus Amaurolithus provides three successive first occurrences (FOs): A. primus, A. cf. amplificus and A. delicatus, dated at 7.446, 7.434 and 7.226 Ma, respectively. Other bioevents include the base and top of the 'small reticulofenestrids' Acme, dated at 7.644 and 6.697 Ma, and the FO, FCO and LO of R. rotaria, dated at 7.405, 7.226 and 6.771 Ma. These events appear to be useful in improving biostratigraphic resolution in the Tortonian-Messinian boundary interval, at least for the Mediterranean. Quantitative analysis revealed changes in the calcareous nannofossil assemblage associated with the sapropels. The observed fluctuations suggest a single mechanism for sapropel formation in the Mediterranean during the late Neogene. Sapropels are characterized by a decrease in the total number of coccoliths, interpreted mainly as a reduction in calcareous nannofossil production due to increased siliceous plankton production during spring blooms; and an increase in reworked specimens, interpreted to reflect enhanced continental input via river run-off. An increase in abundance of the genus Rhabdosphaera can be explained by opportunistic behavior at the end of the spring bloom when nutrient levels start to become impoverished. As far as sea surface water temperature indicators are concerned, warm water D. pentaradiatus shows positive fluctuations in sapropels while cooler water D. intercalaris and C. pelagicus show negative fluctuations.

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Section: Discussionmentioning

confidence: 94%

Calcareous nannofossil biostratigraphy of the M. del Casino section (northern Apennines, Italy) and paleoceanographic conditions at times of Late Miocene sapropel formation

Negri

Giunta

Hilgen

et al. 1999

Marine Micropaleontology

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“…The relative abundances of F. profunda decrease with decreased transparency in the euphotic water column at the northwestern margin of the Pacific (Ahagon et al, 1993). Gradual increases in water turbidity caused by increased particle and nutrient supplies from more exposed land areas, caused by lowering sea level, may be responsible for the decreasing trend of F. profunda starting from the lower upper Pliocene (Sample 159-959C-6H-2, 80−82.5 cm; 42.61 mbsf; 2.82 Ma) through uppermost Pleistocene.…”

Section: Paleoclimatic and Paleoceanographic History Of Hole 959cmentioning

confidence: 96%

“…It lives only in the lower photic layer (150−200 m) and prefers low light and high nutrients (Honjo, 1977;Okada and Honjo, 1973;Honjo and Okada, 1974;Molfino and McIntyre, 1990a). The variations of this species were interpreted as changes in water depth, nutricline (by proxy, thermocline) depth, and water transparency and turbidity (Okada and Honjo, 1973;Honjo and Okada, 1974;Honjo, 1977;McIntyre, 1977, 1979;Reid, 1980;Okada, 1984Okada, , 1990Molfino andMcIntyre, 1990a, 1990b;Ahagon et al, 1993).…”

Section: Paleoclimatic and Paleoceanographic History Of Hole 959cmentioning

confidence: 99%

“…Nutricline depth is defined by a level of PO 4 of 1.0 µmol/liter, and it varies between 50 and 200 m (Molfino and McIntyre, 1990b). Therefore, there is a close relationship between the relative abundances of F. profunda and the nutrient content in the euphotic water column (Molfino andMcIntyre, 1990a, 1990b;Ahagon et al, 1993). When the nutricline (by proxy, thermocline) becomes deep, the production of F. profunda in the upper euphotic layer is greater than the production of coccolithophorids (Molfino andMcIntyre, 1990a, 1990b).…”

Section: Paleoclimatic and Paleoceanographic History Of Hole 959cmentioning

confidence: 99%

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PliocenePleistocene paleoclimatic and paleoceanographic history of Site 959, eastern equatorial Atlantic Ocean

Shin¹

1998

Proceedings of the Ocean Drilling Program, 159 Scientific Results

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Pliocene-Pleistocene paleoclimatic and paleoceanographic variables were examined based on the number (in 20 view fields) and relative abundances of calcareous nannofossil F. profunda, number of discoasters in 20 view fields, relative abundances of warm-and cool-water indicator calcareous nannofossils, and the species diversity indices S, H(S), and E. The early Pliocene is characterized by relatively shallow nutricline (by proxy, thermocline) compared to the late Pliocene as evidenced by lower relative abundances of F. profunda. The early Pliocene contains a higher abundance of discoasters, warm-water indicator calcareous nannofossils, and the species diversity indices S, H(S), and E all suggest warm and stable surface-water conditions. The late Pliocene contains the highest relative abundance of F. profunda, indicating the deepest nutricline and, by proxy, thermocline. Climatic shift and changes in nutricline/thermocline occurred between 2.82 and 3.03 Ma. The surface-water temperature became cool, the thermocline/nutricline depth became shallower, and the primary productivity began to get higher starting from the early late Pliocene (2.82 Ma) to the latest Pleistocene. These paleoceanographic events are shown by significant changes in both number and relative abundances of F. profunda, relative abundances of warm-water indicator calcareous nannofossils, and by the species diversity indices from the early late Pliocene (upper part of Subzone CN 12a; 2.82 Ma) through the latest Pleistocene. The early Pleistocene shows greater variations of the relative abundances of F. profunda and warm-water nannofossils, suggesting unstable and great fluctuation of surface-water temperature and nutricline/thermocline depth. Another climatic cooling starting approximately 2.4 Ma, also shown by the decreasing relative abundances of F. profunda, by warmwater indicator nannofossils, and by the species diversity indices for the younger sediment. The middle and late Pleistocene contain the lowest relative abundances of F. profunda, suggesting the shallowest thermocline/nutricline.

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“…Otra diferencia entre los sitios ODP 1233 y MD07-3128 se relaciona con la presencia de Florisphaera profunda en el testigo ODP 1233 y ausencia de ella en nuestras muestras. Esta especie se caracteriza por vivir en la parte inferior de la zona fótica entre 60 y 180 m de profundidad y es indicadora de aguas oligotróficas (Okada & Honjo, 1973) y su abundancia se ha relacionado también con la transparencia de la columna de agua en el Pacífico noroccidental (Ahagon et al, 1993).…”

Section: Discusión Asociación De Cocolitóforos Y Diversidadunclassified

Cocolitoforos en sedimentos marinos frente a la entrada occidental del Estrecho de Magallanes (53S) revelan cam-bios en la productividad durante los ultimos 30.000 anos

Sánchez

Lange

Flores

et al. 2014

lajar

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Cocolitóforos en sedimentos marinos frente a la entrada occidental delRESUMEN. Se presenta un nuevo registro de producción exportada de cocolitóforos (cocolitos) durante los últimos 30.000 años, basado en el estudio de un testigo de sedimento marino obtenido frente a la entrada occidental del Estrecho de Magallanes (testigo MD07-3128; 53°S, 75ºW). Este testigo reveló la presencia de una asociación compuesta por trece taxones de cocolitóforos dominada por Gephyrocapsa "small" (representando en promedio >80% de la asociación total) y acompañada, en menor proporción (1-10%), por dos morfotipos de Emiliania huxleyi, Coccolithus pelagicus y Calcidiscus leptoporus. La concentración de cocolitos se correlacionó positivamente con el contenido de CaCO3 (P << 0.01; R 2 = 0,63). En general, ambos registros estuvieron en fase con la temperatura superficial del mar derivada de alquenonas (Caniupán et al., 2011), donde los valores máximos en el CaCO3 (>30%) y la abundancia de cocolitos (~10 9 cocolitos g -1 sedimento seco) coincidieron con periodos relativamente cálidos (e.g., el Holoceno). Se hallaron marcadas diferencias al comparar estos datos con el registro de cocolitos de Saavedra-Pellitero et al. (2011) para el sitio ODP 1233 a los 41°S: en el sitio ODP 1233 la producción de cocolitóforos fue máxima durante el Último Máximo Glacial en respuesta a la advección hacia el norte de las aguas ricas en macronutrientes de la corriente Circumpolar Antártica. En contraste, el sitio MD07-3128 experimentó al mismo tiempo una baja en productividad de cocolitóforos probablemente relacionada al efecto negativo ejercido por un alto aporte de material terrígeno y agua de deshielo proveniente del gran casquete de hielo patagónico. Palabras clave: cocolitóforos, Último Máximo Glacial, Holoceno, sur de Chile. Cocolithophores in marine sediments off the western entrance of the Strait ofMagellan reveal changes in productivity over the past 30,000 years ABSTRACT. We present a new record of coccolithophore (coccoliths) export productivity for the past 30,000 years based on the study of a marine sediment core collected at the western entrance of the Strait of Magellan (Core MD07-3128; 53°S, 75ºW). This sediment core revealed the presence of an assemblage composed by thirteen coccolithophore taxa, dominated by small Gephyrocapsa (>80% of the total assemblage on the average) and accompanied, in less proportions (1-10%), by two morphotypes of Emiliana huxleyi, Coccolithus pelagicus and Calcidiscus leptoporus. Coccolith concentration and CaCO3 content were strongly correlated (P << 0.01; R 2 = 0.63). In general, both records were in phase with alkenone-derived sea-surface temperature (Caniupán et al., 2011) where maximum values of CaCO3 (>30%) and coccolith abundance (~10 9 coccoliths g -1 dry sediment) coincided with relatively warm periods (e.g., the Holocene). We found marked differences when comparing our data with a coccolith record published by Saavedra-Pellitero et al. (2011) for ODP Site 1233 at 41°S: At ODP Site 1233, coccolithophore prod...

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Florisphaera profunda, a possible nannoplankton indicator of late Quaternary changes in sea-water turbidity at the northwestern margin of the Pacific

Cited by 137 publications

References 13 publications

Calcareous nannofossil biostratigraphy of the M. del Casino section (northern Apennines, Italy) and paleoceanographic conditions at times of Late Miocene sapropel formation

Calcareous nannofossil biostratigraphy of the M. del Casino section (northern Apennines, Italy) and paleoceanographic conditions at times of Late Miocene sapropel formation

PliocenePleistocene paleoclimatic and paleoceanographic history of Site 959, eastern equatorial Atlantic Ocean

Cocolitoforos en sedimentos marinos frente a la entrada occidental del Estrecho de Magallanes (53S) revelan cam-bios en la productividad durante los ultimos 30.000 anos

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Florisphaera profunda, a possible nannoplankton indicator of late Quaternary changes in sea-water turbidity at the northwestern margin of the Pacific

Cited by 137 publications

References 13 publications

Calcareous nannofossil biostratigraphy of the M. del Casino section (northern Apennines, Italy) and paleoceanographic conditions at times of Late Miocene sapropel formation

Calcareous nannofossil biostratigraphy of the M. del Casino section (northern Apennines, Italy) and paleoceanographic conditions at times of Late Miocene sapropel formation

PliocenePleistocene paleoclimatic and paleoceanographic history of Site 959, eastern equatorial Atlantic Ocean

Cocolitoforos en sedimentos marinos frente a la entrada occidental del Estrecho de Magallanes (53S) revelan cam-bios en la productividad durante los ultimos 30.000 anos

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PliocenePleistocene paleoclimatic and paleoceanographic history of Site 959, eastern equatorial Atlantic Ocean