Publications associées à Foraminifera

Diagenetic isotope exchange in biocalcites for paleoclimate reconstruction

The oxygen isotope compositions of fossil biocalcites, such as foraminifera, bivalves, brachiopods, and belemnites have allowed for reconstructions of sea surface and deep ocean temperatures throughout the Phanerozoic and constitute the most important reco ...

EPFL2024

Rapid grain boundary diffusion in foraminifera tests biases paleotemperature records

Anders Meibom, Jaroslaw Hubert Stolarski, Arthur Adams, Deyanira Graciela Cisneros Lazaro, Jinming Guo, Lukas Baumgartner

The paleoseawater temperature record from the oxygen isotope compositions of fossil foraminifera tests may be biased by up to about 1 degrees C due to grain-boundary diffusion alone, according to isotope exchange experiments on foraminifera tests. The oxyg ...

2023

Kleptoplast distribution, photosynthetic efficiency and sequestration mechanisms in intertidal benthic foraminifera

Anders Meibom, Charlotte Madeleine Nicole Lekieffre, Emmanuelle Geslin, Michael Kühl

Foraminifera are ubiquitously distributed in marine habitats, playing a major role in marine sediment carbon sequestration and the nitrogen cycle. They exhibit a wide diversity of feeding and behavioural strategies (heterotrophy, autotrophy and mixotrophy) ...

SPRINGERNATURE2022

Ammonium is the preferred source of nitrogen for planktonic foraminifer and their dinoflagellate symbionts

Anders Meibom, Charlotte Madeleine Nicole Lekieffre, Emmanuelle Geslin

The symbiotic planktonic foraminiferaOrbulina universainhabits open ocean oligotrophic ecosystems where dissolved nutrients are scarce and often limit biological productivity. It has previously been proposed thatO. universameets its nitrogen (N) requiremen ...

ROYAL SOC2020

Heterotrophic Foraminifera Capable of Inorganic Nitrogen Assimilation

Anders Meibom, Charlotte Madeleine Nicole Lekieffre, Emmanuelle Geslin

Nitrogen availability often limits biological productivity in marine systems, where inorganic nitrogen, such as ammonium is assimilated into the food web by bacteria and photoautotrophic eukaryotes. Recently, ammonium assimilation was observed in kleptopla ...

Frontiers Media SA2020

A Reassessment of of the geochemical and isotopic fidelity of biogenic carbonates

Anders Meibom, Jaroslaw Hubert Stolarski, Arthur Adams, Deyanira Graciela Cisneros Lazaro, Jinming Guo, Tarek Axel Vennemann

Oxygen isotope compositions of calcite foraminifera tests are considered to be a robust palaeotemperature proxy at earth-surface conditions, where diffusion is slow. Recrystallization of tests during diagenesis may be optically identified and is often the ...

2019

Assimilation, translocation, and utilization of carbon between photosynthetic symbiotic dinoflagellates and their planktic foraminifera host

Anders Meibom, Charlotte Madeleine Nicole Lekieffre, Emmanuelle Geslin

Some species of planktic foraminifera inhabiting oligotrophic surface water environments are in an obligate symbiotic relationship with dinoflagellate microalgae, which can assimilate carbon (C) through photosynthesis. However, the mechanism and dynamics o ...

2018

An overview of cellular ultrastructure in benthic foraminifera: New observations of rotalid species in the context of existing literature

Anders Meibom, Charlotte Madeleine Nicole Lekieffre, Emmanuelle Geslin

We report systematic transmission electron microscope (TEM) observations of the cellular ultrastructure of selected, small rotalid benthic foraminifera. Nine species from different environments (intertidal mudflat, fjord, and basin) were investigated: Ammo ...

2018

Inorganic carbon and nitrogen assimilation in cellular compartments of a benthic kleptoplastic foraminifer

Anders Meibom, Charlotte Madeleine Nicole Lekieffre, Maria-Evangelia Giovani, Emmanuelle Geslin

Haynesina germanica, an ubiquitous benthic foraminifer in intertidal mudflats, has the remarkable ability to isolate, sequester, and use chloroplasts from microalgae. The photosynthetic functionality of these kleptoplasts has been demonstrated by measuring ...

Nature Research2018

Innovative TEM-coupled approaches to study foraminiferal cells

Anders Meibom, Stéphane Laurent Escrig, Charlotte Madeleine Nicole Lekieffre, Emmanuelle Geslin

Transmission electron microscope (TEM) observation has revealed much about the basic cell biology of foraminifera. Yet, there remains much we do not know about foraminiferal cytology and physiology, especially for smaller benthic foraminifera, which inhabi ...

2018

Burial-induced oxygen-isotope re-equilibration of fossil foraminifera explains ocean paleotemperature paradoxes

Anders Meibom

Oxygen-isotope compositions of fossilised planktonic and benthic foraminifera tests are used as proxies for surface-and deep-ocean paleotemperatures, providing a continuous benthic record for the past 115 Ma. However, visually imperceptible processes can a ...

Springer Nature2017

Correlated TEM-NanoSIMS investigation of foraminiferal metabolism

Charlotte Madeleine Nicole Lekieffre

Foraminifera are ubiquitous eukaryotic protists inhabiting all types of marine environments. The chemical and isotopic compositions of their carbonate tests are commonly used as proxies for paleo-environmental conditions. However, while foraminifera repres ...

EPFL2017

Surviving anoxia in marine sediments: The metabolic response of ubiquitous benthic foraminifera (Ammonia tepida)

Anders Meibom, Stéphane Laurent Escrig, Charlotte Madeleine Nicole Lekieffre, Emmanuelle Geslin

High input of organic carbon and/or slowly renewing bottom waters frequently create periods with low dissolved oxygen concentrations on continental shelves and in coastal areas; such events can have strong impacts on benthic ecosystems. Among the meiofauna ...

Public Library of Science2017

Sequestered Chloroplasts In The Benthic Foraminifer Haynesina Germanica: Cellular Organization, Oxygen Fluxes And Potential Ecological Implications

Charlotte Madeleine Nicole Lekieffre, Emmanuelle Geslin

Haynesina germanica is a coastal benthic foraminifer known to sequester chloroplasts from benthic pennate diatoms. This study investigates its cellular organization, as well as the oxygen consumption and production rates under dark and light conditions. Th ...

2017

Unveiling exceptional Baltic bog ecohydrology, autogenic succession and climate change during the last 2000 years in CE Europe using replicate cores, multi-proxy data and functional traits of testate amoebae

Vincent Eric Jules Jassey, Mariusz Lamentowicz

We present the results of high-resolution, multi-proxy palaeoecological investigations of two parallel peat cores from the Baltic raised bog Mechacz Wielki in NE Poland. We aim to evaluate the role of regional climate and autogenic processes of the raised ...

Pergamon-Elsevier Science Ltd2017

Travertines associated with the Alhama-Jaraba thermal waters (NE, Spain): Genesis and geochemistry

Freshwater carbonates are interesting archives in palaeoenvironmental reconstructions. However, more studies of those systems are needed to fully understand past environments. In this work the actively-forming travertines of the Alhama-Jaraba thermal syste ...

Elsevier Science Bv2017

Hydrological dynamics and fire history of the last 1300 years in western Siberia reconstructed from a high-resolution, ombrotrophic peat archive

Alexandre Buttler, Vincent Eric Jules Jassey, Mariusz Lamentowicz

Siberian peatlands provide records of past changes in the continental climate of Eurasia. We analyzed a core from Mukhrino mire in western Siberia to reconstruct environmental change in this region over the last 1300 years. The pollen analysis revealed lit ...

Academic Press Inc Elsevier Science2015

Plant functional diversity drives niche-size-structure of dominant microbial consumers along a poor to extremely rich fen gradient

Vincent Eric Jules Jassey, Bjorn Jozef Maria Robroek, Mariusz Lamentowicz

Plant community composition is recognized more and more for playing an important role in ecosystem processes, such as C cycling. In particular, plant functional type (PFT) composition seems to have a key regulatory role, yet the underlying mechanisms in ...

Wiley-Blackwell2014

A new model for biomineralization and trace-element signatures of Foraminifera tests

Anders Meibom

The Mg/Ca ratio of Foraminifera calcium carbonate tests is used as proxy for seawater temperature and widely applied to reconstruct global paleo-climatic changes. However, the mechanisms involved in the carbonate biomineralization process are poorly unders ...

Copernicus Gesellschaft Mbh2013

Holocene changes in climate and land use drove shifts in the diversity of testate amoebae in a subalpine pond

Mariusz Lamentowicz

Testate amoebae that inhabit peat are sensitive indicators of water table position. In this study, we used testate amoebae in sediments from a mire in the western Alps (Lac du Thyl) to: (1) reconstruct the hydrology of the site over the last 7,000 years, ( ...

Springer2013