Planktic Foraminifers in the Modern Ocean

Schiebel, Ralf; Hemleben, Christoph

doi:10.1007/978-3-662-50297-6

Cited by 263 publications

(526 citation statements)

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“…Anderson and Bé (1978) and Anderson and Lee (1991) both describe the main organelles and features observed in foraminiferal cells (e.g., nuclei, ribosomes, endoplasmic reticulum, Golgi, lysosomes and digestive vacuoles, peroxisomes, mitochondria, fibrillar bodies, cytoskeletal structures) but the source of all their TEM images except for one was planktonic foraminifera or LBF. Hemleben et al (1989) and Schiebel and Hemleben (2017) thoroughly described the cytology of planktonic foraminifera.…”

Section: Brief History Of Foraminiferal Tem Studiesmentioning

confidence: 99%

Introduction to the Special Issue entitled “Benthic Foraminiferal Ultrastructure Studies”

Bernhard

Geslin

2018

Marine Micropaleontology

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Section: Brief History Of Foraminiferal Tem Studiesmentioning

confidence: 99%

Introduction to the Special Issue entitled “Benthic Foraminiferal Ultrastructure Studies”

Bernhard

Geslin

2018

Marine Micropaleontology

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“…G. sacculifer -it makes up less than 5% of the planktic foraminiferal assemblage around the LBB today (Siccha and Kučera, 2017) -is abundant in the Caribbean Sea and tropical Atlantic and commonly used as a tracer of tropical waters and geographical shifts of the ITCZ (Poore et al, 2003;Vautravers et al, 2007). Also, G. ruber (pink) shows rather coherent abundance maxima in the tropics (between 20°N and 20°S), while no such affinity is observed for G. ruber (white) and G. conglobatus (Siccha and Kučera, 2017;Schiebel and Hemleben, 2017). Therefore, fluctuations in relative 260 abundances of G. sacculifer and G. ruber (pink) are referred here as to represent a warm tropical end-member (Fig.…”

Section: Early Mis 5ementioning

confidence: 99%

The last interglacial (MIS 5e) cycle at Little Bahama Bank: A history of climate and sea-level changes

Zhuravleva

Bauch

2018

Preprint

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Abstract. Shallow-water sediments of the Bahama region containing the last interglacial (MIS 5e) are ideal to investigate the region's sensitivity to past climatic and sea level changes. Here we present new faunal, isotopic and XRF-sediment core data 10 from the northern slope of the Little Bahama Bank. The results suggest that the bank top remained flooded across the last interglacial "plateau", ~129-117 ka, arguing for a relative sea level above -6 m for this time period. In addition, climatic variability, which today is closely coupled with movements of the intertropical convergence zone (ITCZ), is interpreted based on stable isotopes and foraminiferal assemblage records. During early MIS 5e, the mean annual ITCZ position moved northward in line with increased solar forcing and a recovered Atlantic Meridional Overturning Circulation (AMOC). The 15 early MIS 5e warmth peak was intersected, however, by a millennial-scale cooling event, consistent with a southward shift in the mean annual ITCZ position. This tropical shift is ascribed to the transitional climatic regime of early MIS 5e, characterized by persistent high-latitude freshening and, thereby, unstable AMOC mode. Our records from the Bahama region demonstrate that not only was there a tight relation between local sedimentation regimes and last interglacial sea level history, via the atmospheric forcing we could further infer an intra-interglacial connectivity between the polar and subtropical latitudes that 20 left its imprint also on the ocean circulation.

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“…The test morphology and chemical composition to a certain extent depend on the environment (Schiebel et al, 2017;de Nooijer et al, 2014). The 5 calcification process of the foraminiferal test is the phase of growth in which the elemental and isotopic compositions of the test is determined, and is also the key generating their morphological diversity.…”

mentioning

confidence: 99%

Weaving of biomineralization framework in rotaliid foraminifera: Implications for paleoenvironmental reconstructions

Nagai

Uematsu²,

Chen

et al. 2018

Preprint

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Abstract. Foraminifera are commonly used to reconstruct paleoenvironmental conditions based on the taxonomical composition, as well as elemental and/or isotopic signatures of their calcareous tests. A major problem, often referred to as the 'vital effect', is that such geochemical signatures stored in inorganic calcium carbonates differ greatly under the same environmental conditions. This effect was previously explained by proportional contributions from passive vs active ion 5 transport patterns, but their details are still investigated. In this study, the functional role of pseudopodial structures during chamber formation is elucidated by detailed observation of Ammonia beccarii (Linnaeus) using a time-lapse optical imaging system and high-resolution electron microscopy. For the first time, we document triple organic layers sandwiching carbonate precipitation sites. The three major organic layers (outer organic layer, primary organic sheet, and inner organic layer) are formed by an initial framework of pseudopodia overlaid with further layer-like pseudopodia. The POS seems to facilitate 10 early calcium carbonate nucleation, then entrapped by double precipitation sites. We further show that calcification starts when outer/inner organic layers still reveal tiny gaps (holes within the framework) that may serve as pathways for passive ion exchange (e.g., Mg 2+ ) between seawater and the confined precipitation space. Nevertheless, the majority of wall thickening occurs when the precipitation site is completely isolated from seawater that implicates of active ion exchange.This may explain the differences in Mg/Ca ratios in early and later stages of calcification observed in previous studies. Our 15 study resolves a key 'missing piece' in understanding foraminiferal calcification. The 'vital effect' is directly linked to spatio-temporal organization of the 'biomineralization sandwich' controlled by the three major organic layers. This study exemplifies the importance of culture experiments and in-depth observations of living organisms in order to interpret and calibrate biogeochemical proxies.

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Planktic Foraminifers in the Modern Ocean

Cited by 263 publications

References 0 publications

Introduction to the Special Issue entitled “Benthic Foraminiferal Ultrastructure Studies”

Introduction to the Special Issue entitled “Benthic Foraminiferal Ultrastructure Studies”

The last interglacial (MIS 5e) cycle at Little Bahama Bank: A history of climate and sea-level changes

Weaving of biomineralization framework in rotaliid foraminifera: Implications for paleoenvironmental reconstructions

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