@article{WurzbacherAttermeyerKettneretal.2017, author = {Wurzbacher, Christian and Attermeyer, Katrin and Kettner, Marie Therese and Flintrop, Clara and Warthmann, Norman and Hilt, Sabine and Grossart, Hans-Peter and Monaghan, Michael T.}, title = {DNA metabarcoding of unfractionated water samples relates phyto-, zoo- and bacterioplankton dynamics and reveals a single-taxon bacterial bloom}, series = {Environmental microbiology reports}, volume = {9}, journal = {Environmental microbiology reports}, publisher = {Wiley}, address = {Hoboken}, issn = {1758-2229}, doi = {10.1111/1758-2229.12540}, pages = {383 -- 388}, year = {2017}, abstract = {Most studies of aquatic plankton focus on either macroscopic or microbial communities, and on either eukaryotes or prokaryotes. This separation is primarily for methodological reasons, but can overlook potential interactions among groups. Here we tested whether DNA metabarcoding of unfractionated water samples with universal primers could be used to qualitatively and quantitatively study the temporal dynamics of the total plankton community in a shallow temperate lake. Significant changes in the relative proportions of normalized sequence reads of eukaryotic and prokaryotic plankton communities over a 3-month period in spring were found. Patterns followed the same trend as plankton estimates measured using traditional microscopic methods. The bloom of a conditionally rare bacterial taxon belonging to Arcicella was characterized, which rapidly came to dominate the whole lake ecosystem and would have remained unnoticed without metabarcoding. The data demonstrate the potential of universal DNA metabarcoding applied to unfractionated samples for providing a more holistic view of plankton communities.}, language = {en} } @misc{FrenkenAlacidBergeretal.2017, author = {Frenken, Thijs and Alacid, Elisabet and Berger, Stella A. and Bourne, Elizabeth Charlotte and Gerphagnon, Melanie and Großart, Hans-Peter and Gsell, Alena S. and Ibelings, Bas W. and Kagami, Maiko and Kupper, Frithjof C. and Letcher, Peter M. and Loyau, Adeline and Miki, Takeshi and Nejstgaard, Jens C. and Rasconi, Serena and Rene, Albert and Rohrlack, Thomas and Rojas-Jimenez, Keilor and Schmeller, Dirk S. and Scholz, Bettina and Seto, Kensuke and Sime-Ngando, Telesphore and Sukenik, Assaf and Van de Waal, Dedmer B. and Van den Wyngaert, Silke and Van Donk, Ellen and Wolinska, Justyna and Wurzbacher, Christian and Agha, Ramsy}, title = {Integrating chytrid fungal parasites into plankton ecology: research gaps and needs}, series = {Environmental microbiology}, volume = {19}, journal = {Environmental microbiology}, publisher = {Wiley}, address = {Hoboken}, issn = {1462-2912}, doi = {10.1111/1462-2920.13827}, pages = {3802 -- 3822}, year = {2017}, abstract = {Chytridiomycota, often referred to as chytrids, can be virulent parasites with the potential to inflict mass mortalities on hosts, causing e.g. changes in phytoplankton size distributions and succession, and the delay or suppression of bloom events. Molecular environmental surveys have revealed an unexpectedly large diversity of chytrids across a wide range of aquatic ecosystems worldwide. As a result, scientific interest towards fungal parasites of phytoplankton has been gaining momentum in the past few years. Yet, we still know little about the ecology of chytrids, their life cycles, phylogeny, host specificity and range. Information on the contribution of chytrids to trophic interactions, as well as co-evolutionary feedbacks of fungal parasitism on host populations is also limited. This paper synthesizes ideas stressing the multifaceted biological relevance of phytoplankton chytridiomycosis, resulting from discussions among an international team of chytrid researchers. It presents our view on the most pressing research needs for promoting the integration of chytrid fungi into aquatic ecology.}, language = {en} } @article{RojasJimenezWurzbacherBourneetal.2017, author = {Rojas-Jimenez, Keilor and Wurzbacher, Christian and Bourne, Elizabeth Charlotte and Chiuchiolo, Amy and Priscu, John C. and Grossart, Hans-Peter}, title = {Early diverging lineages within Cryptomycota and Chytridiomycota dominate the fungal communities in ice-covered lakes of the McMurdo Dry Valleys, Antarctica}, series = {Scientific reports}, volume = {7}, journal = {Scientific reports}, publisher = {Nature Publ. Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-017-15598-w}, pages = {11}, year = {2017}, abstract = {Antarctic ice-covered lakes are exceptional sites for studying the ecology of aquatic fungi under conditions of minimal human disturbance. In this study, we explored the diversity and community composition of fungi in five permanently covered lake basins located in the Taylor and Miers Valleys of Antarctica. Based on analysis of the 18S rRNA sequences, we showed that fungal taxa represented between 0.93\% and 60.32\% of the eukaryotic sequences. Cryptomycota and Chytridiomycota dominated the fungal communities in all lakes; however, members of Ascomycota, Basidiomycota, Zygomycota, and Blastocladiomycota were also present. Of the 1313 fungal OTUs identified, the two most abundant, belonging to LKM11 and Chytridiaceae, comprised 74\% of the sequences. Significant differences in the community structure were determined among lakes, water depths, habitat features (i.e., brackish vs. freshwaters), and nucleic acids (DNA vs. RNA), suggesting niche differentiation. Network analysis suggested the existence of strong relationships among specific fungal phylotypes as well as between fungi and other eukaryotes. This study sheds light on the biology and ecology of basal fungi in aquatic systems. To our knowledge, this is the first report showing the predominance of early diverging lineages of fungi in pristine limnetic ecosystems, particularly of the enigmatic phylum Cryptomycota.}, language = {en} } @article{WurzbacherFuchsAttermeyeretal.2017, author = {Wurzbacher, Christian and Fuchs, Andrea and Attermeyer, Katrin and Frindte, Katharina and Grossart, Hans-Peter and Hupfer, Michael and Casper, Peter and Monaghan, Michael T.}, title = {Shifts among Eukaryota, Bacteria, and Archaea define the vertical organization of a lake sediment}, series = {Microbiome}, volume = {5}, journal = {Microbiome}, publisher = {BioMed Central}, address = {London}, issn = {2049-2618}, doi = {10.1186/s40168-017-0255-9}, pages = {16}, year = {2017}, abstract = {Background: Lake sediments harbor diverse microbial communities that cycle carbon and nutrients while being constantly colonized and potentially buried by organic matter sinking from the water column. The interaction of activity and burial remained largely unexplored in aquatic sediments. We aimed to relate taxonomic composition to sediment biogeochemical parameters, test whether community turnover with depth resulted from taxonomic replacement or from richness effects, and to provide a basic model for the vertical community structure in sediments. Methods: We analyzed four replicate sediment cores taken from 30-m depth in oligo-mesotrophic Lake Stechlin in northern Germany. Each 30-cm core spanned ca. 170 years of sediment accumulation according to Cs-137 dating and was sectioned into layers 1-4 cm thick. We examined a full suite of biogeochemical parameters and used DNA metabarcoding to examine community composition of microbial Archaea, Bacteria, and Eukaryota. Results: Community beta-diversity indicated nearly complete turnover within the uppermost 30 cm. We observed a pronounced shift from Eukaryota- and Bacteria-dominated upper layers (<5 cm) to Bacteria-dominated intermediate layers (5-14 cm) and to deep layers (>14 cm) dominated by enigmatic Archaea that typically occur in deep-sea sediments. Taxonomic replacement was the prevalent mechanism in structuring the community composition and was linked to parameters indicative of microbial activity (e.g., CO2 and CH4 concentration, bacterial protein production). Richness loss played a lesser role but was linked to conservative parameters (e.g., C, N, P) indicative of past conditions. Conclusions: By including all three domains, we were able to directly link the exponential decay of eukaryotes with the active sediment microbial community. The dominance of Archaea in deeper layers confirms earlier findings from marine systems and establishes freshwater sediments as a potential low-energy environment, similar to deep sea sediments. We propose a general model of sediment structure and function based on microbial characteristics and burial processes. An upper "replacement horizon" is dominated by rapid taxonomic turnover with depth, high microbial activity, and biotic interactions. A lower "depauperate horizon" is characterized by low taxonomic richness, more stable "low-energy" conditions, and a dominance of enigmatic Archaea.}, language = {en} }