Person:
Martín Cereceda, María Mercedes

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First Name
María Mercedes
Last Name
Martín Cereceda
URI
https://hdl.handle.net/20.500.14352/74409
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Biológicas
Department
Genética, Fisiología y Microbiología
Area
Microbiología
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2008 - 200912010 - 20181
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Author: Martín Cereceda, María Mercedes × Subject: 593.1 ×

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Now showing 1 - 2 of 2
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    Easy Visualization of the Protist Oxyrrhis marina Grazing on a Live Fluorescently Labelled Heterotrophic Nanoflagellate
    (Current Microbiology, 2008) Martín Cereceda, María Mercedes; Williams, Richard Alexander John; Novarino, Gianfranco
    Planktonic heterotrophic flagellates are ubiquitous eukaryotic microorganisms that play a crucial role in carbon and nutrient fluxes through pelagic food webs. Here we illustrate for the first time a grazing model of planktonic dinoflagellate, Oxyrrhis marina, on the heterotrophic nanoflagellate Goniomonas amphinema, using the DNAbinding fluorescent dye Hoechst 33342. A solution of 1 lg/mL of the fluorochrome allowed viability of the prey for at least 48 hours, provided low fluorescence quenching, and labelled the flagellate without masking the cytoplasm. After 2 hours of contact between the fluorescent prey and the predator, O. marina population had preyed on live G.amphinema at an ingestion rate of 2.2 prey Oxyrrhis-1 h-1. Results show that this model is a time-effective and inexpensive approach for the direct observation of heterotrophic flagellate grazing. The fact that prey remain alive while predation occurs, as well as the low rate of quenching, could be of help in studying the fate of realtime trophic interactions between protists in microbial webs.
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    Endemicity and climatic niche differentiation in three marine ciliated protists
    (Limnology and Oceanography, 2018) Williams, Richard Alexander John; Owens, Hannah L; Clamp, John; Peterson, A Townsend; Warren, Alan; Martín Cereceda, María Mercedes
    The biogeographic pattern of single-celled eukaryotes (protists), including ciliates, is poorly understood. Most marine species are believed to have a relatively high dispersal potential, such that both globally distributed and geographically isolated taxa exist. Primary occurrence data for three large, easily identified ciliate species, Parafavella gigantea, Schmidingerella serrata, and Zoothamnium pelagicum, and environmental data drawn from the National Oceanic and Atmospheric Administration’s World Ocean Atlas were used to estimate each species’ spatial and environmental distributions using Maxent v3.3.3k. The predictive power of the models was tested with a series of spatial stratification studies, which were evaluated using partial receiver operating characteristic (ROC) statistics. Differences between niches occupied by each taxon were evaluated using background similarity tests. All predictions showed significant ability to anticipate test points. The null hypotheses of niche similarity were rejected in all background similarity tests comparing the niches among the three species. This article provides the first quantitative assessment of environmental conditions associated with three species of ciliates and a first estimate of their spatial distributions in the North Atlantic, which can serve as a benchmark against which to document distributional shifts. These species follow consistent, predictable patterns related to climate and environmental biochemistry; the importance of climatic conditions as regards protist distributions is noteworthy considering the effects of global climate change.