Charlotte Madeleine Nicole Lekieffre

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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 ...

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 ...

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 ...

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 ...

The assimilation of inorganic compounds in foraminiferal metabolism compared to predation or organic matter assimilation is unknown. Here, we investigate possible inorganic-compound assimilation in Nonionellina labradorica, a common kleptoplastidic benthic ...

Dissolved inorganic nitrogen (DIN) is one of the key major nutrients crucial for regulating marine productivity. Photosynthetic endosymbiosis, as seen in organisms like stony corals and foraminifera, appear to alleviate nutrient limitations in surface ocea ...

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 ...

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 ...

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 ...

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 ...

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 ...

Nitrogen and sulfur are key elements in the biogeochemical cycles of marine ecosystems to which benthic foraminifera contribute significantly. Yet, cell-specific assimilation of ammonium, nitrate and sulfate by these protists is poorly characterized and un ...

Charlotte Madeleine Nicole Lekieffre

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Correlated TEM-NanoSIMS investigation of foraminiferal metabolism

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

Heterotrophic Foraminifera Capable of Inorganic Nitrogen Assimilation

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

Kleptoplastidic benthic foraminifera from aphotic habitats: insights into assimilation of inorganic C, N and S studied with sub-cellular resolution

Symbiont regulation of nitrogen metabolism and excretion in tropical planktonic foraminifera

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

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

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

Innovative TEM-coupled approaches to study foraminiferal cells

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

Ammonium and Sulfate Assimilation Is Widespread in Benthic Foraminifera

Kleptoplastic foraminifera: the transformation of heterotrophic unicellular eukaryotes into photosynthetic organisms

Changes in ultrastructural features of the foraminifera Ammonia spp. in response to anoxic conditions: Field and laboratory observations

Ammonium and nitrate assimilation in benthic foraminiferal cells: NanoSIMS observations and enzymatic pathways