poster presentations

Poster presentations (total 19)

2019

1. Zagreb, Croazia

   Comparative analysis of the epibiotic diatom community on loggerhead sea turtles in pre- and post-hospitalization period.

   Filek, Klara,  Majewska, Roksana, Vijver, Bart, Robert, Käthe, Frankovich, Thomas A., Ashworth, Matt P., and Bosak, Sunčica

   VII European Phycological Congress 2019
2. Norwich, UK

   A polyphasic approach for identification of epibiotic diatoms associated with loggerhead sea turtles in the Adriatic Sea.

   Filek, Klara, Kanjer, Lucija, Matek, Antonija, Trotta, Adriana,  Majewska, Roksana, Ashworth, Matt P., Vijver, Bart, and Bosak, Sunčica

   The Molecular Life of Diatoms EMBO Workshop 2019
3. Norwich, UK

   DNA metabarcoding and morphological analyses of the diatom biofilm associated with loggerhead sea turtles in the Mediterranean Sea.

   Bosak, Sunčica, Visic, H., Filek, Klara, Robert, Käthe, Vijver, Bart, Trotta, Adriana, Panagopolou, A., and Majewska, Roksana

   The Molecular Life of Diatoms EMBO Workshop 2019
4. Belvaux, Luxembourg

   New observations on some sea turtle-associated Craspedostauros species.

   Bosak, Sunčica,  Majewska, Roksana, Filek, Klara, and Vijver, Bart

   XII Central European Diatom Meeting 2019

2018

1. Stellenbosch, South Africa

   Hitchhiking across the oceans: a summary of a 3-year study on sea turtle-associated diatoms.

   Majewska, Roksana

   I Postdoctoral Conference of Southern Africa 2018

   Abs URL

   Aquatic animals, both marine and freshwater, provide unique habitats for various macro- and micro organisms. Although diatoms have long been known to grow on aquatic vertebrates such as birds, whales, and dolphins, only recently have the first studies exploring sea turtle-associated diatoms been conducted and several new diatom taxa, including three new genera, have been described. These new taxa show traits of obligate epibionts, which means they may require a direct contact with their basibionts (i.e. the host organism) to develop and survive. Since their first discovery, sea turtle diatoms have attracted growing attention, partly due to their potential use as indicators of sea turtle behavior and health. Research here may help to bridge various gaps in general understanding of both sea turtle and diatom ecology, evolution, and biogeography. However, at present many aspects of the symbiosis-like relationship between these micro- and macro-organisms remain unaddressed and it is not yet understood what factors influence epizoic diatom composition and abundance, and what ecological role and function they have in marine ecosystems. This poster will summarize the on-going investigations and recent findings in sea turtle diatoms that may open many new avenues for future research into marine epibiosis and related areas of study.

2. Berlin, Germany

   New Proschkinia species associated with sea turtles.

   Bosak, Sunčica,  Majewska, Roksana, Frankovich, Thomas A., Ashworth, Matt P., and Vijver, Bart

   XXV International Diatom Symposium 2018
3. Johannesburg, South Africa

   Zoological museum collections as a valuable source of information for epizoic diatom studies.

   Majewska, Roksana, Tessier, Stéphanie, Scheinberg, L., Robinson, Nathan J., Lazo-Wasem, Eric A., Rojas, Lourdes, Pinou, Theodora, Zyskowski, K., Vijver, Bart, Hamilton, Paul, and Poulin, Michael

   XXXI Congress of the Phycological Society of Southern Africa 2018

   URL
4. Edinburgh, UK

   Rafting on macro-algae (Sargassum) of symbiont-bearing Larger Benthic Foraminifera, key to their dispersal in recent and ancient oceans.

   Baumgartner-Mora, Claudia, Briguglio, Antonino, Kocsis, Laszlo,  Majewska, Roksana, Roslim, Amajida, Andjić, Goran, and Baumgartner, Peter O.

   FORAMS 2018

   Abs URL

   The examination of a m-sized macro-algal thallus of Sargassum aquifolium recovered in the South China Sea 60 km off Brunei Darussalam, revealed a rafting community of numerous living, symbiont-bearing, Larger Benthic Foraminifera (LBF), clearly adapted to epiphytic life. The dominant species are: 1. Amphisorus hemprichii that shows both flat growth on "leaves" and curved, "encrusting" growth, folding around rods of Sargassum. 2. Encrusting Formaminifera Planorbulina acervalis, well known to be epiphytic. We also found Calcarina calcar, Baculogypsina sp. and small Benthic Foraminifera in minor numbers. The Amphisorus juveniles show a flat morphology and adults progressively warp as chambers are added to adapt to the surface of algal rods. Sargassum aquifolium is an epilithic macro-alga common in the tropical Indo-West Pacific. Rocky shores are, however, rare along the N-Borneo coast, where this algae, though poorly studied, has not been reported. Amphisorus has not been found by AB in Brunei near-shore samples. It is likely that the thallus has drifted for a long time in the off-shore currents of the South China Sea. SEM-observation of algal rods with attached LBF, fixed in ethanol on board ship, reveal a rich epiphytic diatom community dominated by Cocconeis spp. and including other genera, such as Amphora, Nitzschia, Mastogloia etc. Many frustules are embedded in bacterial clusters. We found numerous diatom frustules engulfed in pseudopodial protoplasm extending from the apertural face of Amphisorus, suggesting feeding by external digestion of diatom soft parts. Our observations suggest that symbiont-bearing LBF can feed, grow and possibly reproduce in an auto-sufficient, floating, epiphytic community, which potentially allows them to disperse along the major surface currents of the world oceans. Once stranded in a suitable shallow-water environment, the community may have a sufficiently large gene pool to settle an evolve, adapting to the local environment. This observation may be key to the dispersal of shallow dwelling LBF, both in the Recent and the Late Mesozoic-Cainozoic, which has been poorly understood. Largely unconstrained hypotheses of the direction of LBF- migration, between the Tethyan, the American and the Indo-Pacific provinces, were based on supposed ancestor-descendant relationships between related taxa in the respective provinces.

5. Berlin, Germany

   Morphological variations in sea turtle-associated “gomphonemoid” diatoms.

   Majewska, Roksana, Vijver, Bart, Frankovich, Thomas A., Ashworth, Matt P., Sullivan, Michael J., and Bosak, Sunčica

   The XXV International Diatom Symposium 2018
6. Berlin, Germany

   Molecular phylogeny of “marine gomphonemoid” diatoms, with particular reference to the epizoic genus Poulinea Majewska, De Stefano & Van de Vijver.

   Ashworth, Matt P., Frankovich, Thomas A., Sullivan, Michael J.,  Majewska, Roksana, Arendt, Mike, Schwenter, Jeffrey, Theriot, Edward, and Stacy, Nicole I.

   XXV International Diatom Symposium 2018

2017

1. Las Vegas, USA

   Diatoms on sea turtles: a summary of recent discoveries.

   Majewska, Roksana, Robinson, Nathan J., Lazo-Wasem, Eric A., Nel, Ronel, Paladino, Frank V., Rojas, Lourdes, Zardus, John D., and Pinou, Theodora

   XXXVII Annual Symposium on Sea Turtle Biology and Conservation 2017
2. Prague, Czech Republic

   Diatom and other phytoplankton communities along a salinity and ph gradient in a tropical estuary (Brunei, Borneo, South East Asia).

   Majewska, Roksana, Adam, Aimimuliani, Mohammad-Noor, Normawaty, Convey, Peter, De Stefano, Mario, and Marshall, David J.

   XI Central European Diatom Meeting 2017

2016

1. Quebec, Canada

   Three new epizoic Achnanthes species (Bacillariophyta) living on marine turtles and manatees.

   Majewska, Roksana, Frankovich, Thomas A., Sullivan, Michael J., Ashworth, Matt P., Stacy, Nicole I., De Stefano, Mario, and Vijver, Bart

   XXIV International Diatom Symposium 2016
2. Lima, Perú

   Epibiotic diatoms are universally present on all sea turtle species.

   Robinson, Nathan J.,  Majewska, Roksana, Lazo-Wasem, Eric A., Nel, Ronel, Paladino, Frank V., Rojas, Lourdes, Zardus, John D., and Pinou, Theodora

   XXXVI Annual Symposium on Sea Turtle Biology and Conservation 2016

2015

1. Ceske Budejovice, Czech Republic

   Summer epiphytic diatom communities from the Ross Sea - a synthesis.

   Majewska, Roksana, Convey, Peter, and De Stefano, Mario

   VI International Conference on Polar and Alpine Microbiology 2015

2013

1. Konin, Poland

   Comparison of diatom communities associated with Plocamium cartliagineum (Plocamiales, Plocamiaceae) from different Antarctic seas.

   Majewska, Roksana, and De Stefano, Mario

   XXXII International Conference of Polish Phycological Society 2013