Cryptic and pseudo-cryptic species are common amongst marine phytoplankton, and may cause misleading inferences of ecological and physiological data of plankton community studies. Deciphering the diversity and distribution of species of the benthic dinoflagellate Ostreopsis is one example, as there are many morphologically indistinct clades that differ greatly genetically and toxicologically from one another. In this study, a new species, Ostreopsis rhodesae from the southern Great Barrier Reef was described. While it initially appeared to be highly similar to several other Ostreopsis species, we found O. rhodesae can be distinguished based on the relative size of the second apical plate (2'), which is twice as long as the APC plate, and separates the third apical (3') from the third precingular (3'') plate. Phylogenetic trees based on the SSU, ITS/5.8S and D1-D2 and D8-D10 regions of the LSU rRNA were well supported, and showed a clear difference to other Ostreopsis clades. Compensatory base changes (CBCs) were identified in helices of the ITS2 between O. rhodesae and O. cf. ovata and O. cf. siamensis, which were also present in the same habitat. Fish gill cell lines were toxic to O. rhodesae, cell extracts but no palytoxin-like analogues were found in them. The findings highlight a case of pseudo-cryptic speciation, found in sympatry with closely related and morphologically similar species, but biologically and functionally distinct.
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http://dx.doi.org/10.1016/j.hal.2016.11.004 | DOI Listing |
Harmful Algae
June 2024
Université Côte d'Azur, CNRS, ECOSEAS, France.
Harmful Algal Blooms (HABs) are increasing in temperate areas, and the growth rates of benthic harmful dinoflagellates may be favoured in the context of global climate change. Benthic dinoflagellates, including species belonging to the Ostreopsis Schmidt genus, are known to develop on the surface of macroalgae and different macroalgal morphotypes and communities could host higher or lower cell abundances. The physical structure of the macroalgal substrate at the small scale (cm, microhabitat scale) and the structural complexity of the macroalgal community at the medium scale (few m, mesohabitat scale) could play a relevant role in bloom facilitation: the hypothesis that Ostreopsis species could be associated with macroalgal turfs and shrubs, structurally less complex communities than canopy-forming macroalgae, is especially under discussion and, if confirmed, could link bloom occurrence to regime shifts in temperate ecosystems.
View Article and Find Full Text PDFHarmful Algae
May 2024
Ifremer, DYNECO/Pelagos, F-29280, Plouzané, France.
Reports of the benthic dinoflagellate Ostreopsis spp. have been increasing in the last decades, especially in temperate areas. In a context of global warming, evidences of the effects of increasing sea temperatures on its physiology and its distribution are still lacking and need to be investigated.
View Article and Find Full Text PDFMar Environ Res
June 2024
Research Group of Experimental and Applied Aquatic Ecology, Federal University of the State of Rio de Janeiro (UNIRIO), Avenida Pasteur, 458 - 307, Urca, Rio de Janeiro, CEP: 22.290-240, Brazil.
Oyster culture is a sustainable solution to food production. However, this activity can be severely impacted by the presence and proliferation of harmful microalgae such as the benthic dinoflagellates Prorocentrum hoffmannianum and Ostreopsis cf. ovata.
View Article and Find Full Text PDFChemosphere
March 2024
Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy; NBFC, National Biodiversity Future Center, Palermo 90133, Italy. Electronic address:
Harmful Algae
February 2024
Laboratório de Microalgas Marinhas, Universidade Federal do Estado do Rio de Janeiro - UNIRIO, Av. Pasteur, 458, Urca, Rio de Janeiro, 22290-240, RJ, Brazil. Electronic address:
Benthic dinoflagellates produce potent toxins that may negatively affect humans and the marine biota. Understanding the factors that stimulate their growth is important for management strategies and to reduce their potential negative impacts. Laboratory cultures have been extensively used to study microalgae physiology and characterize life cycles, nutrition, growth rates, among other processes.
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