Radiolaria Associated with Large Diversity of Marine Alveolates

Bråte, Jon; Krabberød, Anders K.; Dolven, Jane K.; Ose, Randi F.; Kristensen, Tom; Bjørklund, Kjell R.; Shalchian-Tabrizi, Kamran

doi:10.1016/j.protis.2012.04.004

Cited by 64 publications

(50 citation statements)

References 40 publications

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“…However, direct evidence that most MALV clades are parasitic is lacking (Worden et al 2015). The associations observed between MALV and their hosts are equally consistent with symbiotic relationships (Bråte et al 2012), and environmental factors could potentially shift a relationship from commensal to pathogenic (Worden et al 2015). In the present study, the absence of a correlation between symbdec and the COIA co-ordinates indicates that the variability of this trophic group at the inshore station cannot be explained by any of the variables chosen in this study (Fig.…”

Section: Discussionsupporting

confidence: 68%

Small-scale variability of protistan planktonic communities relative to environmental pressures and biotic interactions at two adjacent coastal stations

Genitsaris¹,

Monchy²,

Breton³

et al. 2016

Mar. Ecol. Prog. Ser.

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The aim of this study was to analyze planktonic protistan assemblages under different environmental pressures at 2 adjacent coastal stations (inshore and offshore; ~6.4 km apart) in the eastern English Channel (EEC). Samples were collected between March 2012 and June 2013, and analyzed using bioinformatic analysis and tag pyrosequencing of the V2−V3 hypervariable region of the 18S rRNA gene. In addition to the taxonomic composition of the protistan communities, the detected operational taxonomic units (OTUs) were sorted into 6 major functional groups based on their trophic roles in marine systems. Comparisons of 13 environmental factors, including physical and chemical variables, indicated significant differences between the 2 stations. However, the only significant relationship between environmental pressures and protistan community structure was detected when the trophic role of the OTUs was considered at the inshore station. In order to interpret differences in community structure, the effect of biotic inter actions was investigated through the examination of the co-occurrence networks of the protistan communities at both stations. In terms of the number of edges and connectivity of nodes, the analysis showed that the inshore station had more complex associations between OTUs than the offshore station. This strongly suggests that due to the higher and more variable environmental pressures the inshore station comparatively receives, its protistan community has developed a greater complexity of biotic connections. This in turn reflects the rapid responses of trophic interactions within the entire microbial community.

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Section: Discussionsupporting

confidence: 68%

Small-scale variability of protistan planktonic communities relative to environmental pressures and biotic interactions at two adjacent coastal stations

Genitsaris¹,

Monchy²,

Breton³

et al. 2016

Mar. Ecol. Prog. Ser.

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“…This result may point toward a wide host range of this group. It has been suggested that MALV groups, especially MALV-II, because of their considerable abundance and diversity in marine environments, interact mainly with dinoflagellates and also with other various hosts that include radiolarians, ciliates, as well as copepods and fish (Skovgaard et al, 2005;Harada et al, 2007;Guillou et al, 2008;Bråte et al, 2012). The relationship between MALVs and heterotrophic dinoflagellates in the present study (P < 0.001) suggests that most of these MALVs were dinoflagellate related ones.…”

Section: Bolidomonas Pacifica (98%) [Ocean Waters]supporting

confidence: 50%

“…Parasitic protists are not easily identified in environmental samples, due to their absence of morphological features and endosymbiontic lifestyle (e.g., De Bary, 1879), and therefore information about their diversity, abundance, and ecology had been scarce until quite recently (Scholz et al, 2016). During the last few decades, using the genetic diversity of the 18S rRNA gene, novel eukaryotic taxonomic groups have been revealed within the marine protistan plankton (e.g., López-García et al, 2001;López-García and Moreira, 2008) with great amount of them belonging to potential intracellular symbionts and parasites (e.g., Guillou et al, 2008;Bråte et al, 2012). The development of NGS (Next Generation Sequencing) tools has suggested that marine parasites are more frequent than the literature has reported (e.g., Lefèvre et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Parasitic Eukaryotes in a Meso-Eutrophic Coastal System with Marked Phaeocystis globosa Blooms

et al. 2017

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This study explored the potential interactions and relations of the putative Symbiotic/Decomposer/Parasitic community (SymbDec) with other taxa and predominant environmental parameters in the eastern English Channel (EEC) over a 2.5 years period (32 sampling dates). The EEC is a meso-eutrophic coastal system portrayed by intense reoccurring patterns in plankton succession with blooms of the Haptophyte Phaeocystis globosa and abundant populations of colonial diatoms and dinoflagellate grazers before and after the bloom. The study of the V2-V3 hypervariable region of the 18S rRNA gene allowed an overview of the planktonic community, which consisted of 32 high-level taxonomic groups. Forty-two percent of the identified OTUs belonged to symbionts, decomposers or other putative parasitic taxa belonging mainly to Syndiniales (MALV-MArine ALveolates), Fungi, Cercozoa, Perkinsea, and others, most of which were plankton parasites. We examined the Local Similarity Analysis (LSA) network of lag delayed correlations on the 142 most abundant OTUs (>0.1% of the total number of reads). LSA showed that 99 OTUs had highly significant connections, involving 26 OTUs characterized as potential parasites, and 2 decomposers. The parasitic network had "small world" characteristics, rendering the assemblage more robust to abiotic variations, but more exposed to the removal of highly associated taxa. The majority of the highly connected OTUs belonged to MALV, which were mainly connected with dinoflagellates, suggesting that it might play an important role on dinoflagellate top-down control. The bloom forming P. globosa was not observed in connection with parasitic OTUs in the network. Four environmental parameters (O 2 , N, T, and N/P) were strongly connected with only 11 OTUs, while correlations between microbes dominated the network.

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“…Their absence from our sequencing data indicates that their concentration in Milne Fiord Epishelf Lake must have been quite low. The MALV I found in the deep layer ( Figure 9B) belonged to the Radiolarian-associated clade RAS1 identified by Bråte et al (2012). Radiolarians, though found in many mesopelagic water columns, were very rare in our 30 m samples (<0.001%).…”

Section: Microbial Community Compositionmentioning

confidence: 66%

Microbial Community Structure and Interannual Change in the Last Epishelf Lake Ecosystem in the North Polar Region

et al. 2017

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Climate warming is proceeding rapidly in the polar regions, posing a threat to ice-dependent ecosystems. Among the most vulnerable are microbial-dominated epishelf lakes, in which surface ice-damming of an embayment causes a freshwater layer to overlie the sea, creating an interface between distinct habitats. We characterized the physicochemical and biotic environment of Milne Fiord epishelf lake (82 • N, Canada) in three successive summers (2010)(2011)(2012), and on one date of profiling (5 July 2011) we collected samples for high through-put amplicon sequencing of variable regions of small subunit rRNA to characterize the microbial community (Eukarya, Bacteria and Archaea). Potentially active water column communities were investigated using reverse-transcribed rRNA, and phytoplankton were further characterized by accessory pigment analysis. Cluster analysis of pigment data showed a demarcation between freshwater and marine communities, which was also evident in the sequence data. The halocline community of Eukarya was more similar to the deeper marine sample than to the freshwater surface community, while the Archaea and Bacteria communities at this interface clustered more with surface communities. In 2012, conductivity-depth profiles indicated shallowing of the freshwater layer and mixing across the halocline, accompanied by lower picocyanobacteria and higher picoeukaryote concentrations. Picocyanobacteria cells were more evenly distributed throughout the water column in 2012, implying partial deep mixing. Several mixotrophic taxa of Eukarya were more abundant in the freshwater layer, where low nutrient concentrations may favor this lifestyle. Unusual features of Milne Fiord microbial communities included benthic taxa not previously reported in marine water columns (notably, the archaeon Halobacteriales), and dominance by taxa that are typically present in sparse concentrations elsewhere: for example, the Chlorophyte group Radicarteria and the betaproteobacterium Rhodoferax.Thaler et al. Microbial Communities in an Ice-Dammed Arctic LakeMilne Fiord epishelf lake is the last known lake of this kind remaining in the Arctic, and the fate of this distinct microbial ecosystem may ultimately depend on the stability of the Milne Fiord ice shelf, which has experienced a negative mass balance over the past half century.

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Radiolaria Associated with Large Diversity of Marine Alveolates

Cited by 64 publications

References 40 publications

Small-scale variability of protistan planktonic communities relative to environmental pressures and biotic interactions at two adjacent coastal stations

Small-scale variability of protistan planktonic communities relative to environmental pressures and biotic interactions at two adjacent coastal stations

Parasitic Eukaryotes in a Meso-Eutrophic Coastal System with Marked Phaeocystis globosa Blooms

Microbial Community Structure and Interannual Change in the Last Epishelf Lake Ecosystem in the North Polar Region

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