@article{EngelPiontekGrossartetal.2014,
  author    = {Engel, Anja and Piontek, Judith and Grossart, Hans-Peter and Riebesell, Ulf and Schulz, Kai Georg and Sperling, Martin},
  title     = {Impact of CO2 enrichment on organic matter dynamics during nutrient induced coastal phytoplankton blooms},
  series = {Journal of plankton research},
  volume    = {36},
  journal   = {Journal of plankton research},
  number    = {3},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0142-7873},
  doi       = {10.1093/plankt/fbt125},
  pages     = {641 -- 657},
  year      = {2014},
  abstract  = {A mesocosm experiment was conducted to investigate the impact of rising fCO(2) on the build-up and decline of organic matter during coastal phytoplankton blooms. Five mesocosms (similar to 38 mA(3) each) were deployed in the Baltic Sea during spring (2009) and enriched with CO2 to yield a gradient of 355-862 A mu atm. Mesocosms were nutrient fertilized initially to induce phytoplankton bloom development. Changes in particulate and dissolved organic matter concentrations, including dissolved high-molecular weight (> 1 kDa) combined carbohydrates, dissolved free and combined amino acids as well as transparent exopolymer particles (TEP), were monitored over 21 days together with bacterial abundance, and hydrolytic extracellular enzyme activities. Overall, organic matter followed well-known bloom dynamics in all CO2 treatments alike. At high fCO(2,) higher Delta POC:Delta PON during bloom rise, and higher TEP concentrations during bloom peak, suggested preferential accumulation of carbon-rich components. TEP concentration at bloom peak was significantly related to subsequent sedimentation of particulate organic matter. Bacterial abundance increased during the bloom and was highest at high fCO(2). We conclude that increasing fCO(2) supports production and exudation of carbon-rich components, enhancing particle aggregation and settling, but also providing substrate and attachment sites for bacteria. More labile organic carbon and higher bacterial abundance can increase rates of oxygen consumption and may intensify the already high risk of oxygen depletion in coastal seas in the future.},
  language  = {en}
}
@article{VandenWyngaertSetoRojasJimenezetal.2017,
  author    = {Van den Wyngaert, Silke and Seto, Kensuke and Rojas-Jimenez, Keilor and Kagami, Maiko and Grossart, Hans-Peter},
  title     = {A New Parasitic Chytrid, Staurastromyces oculus (Rhizophydiales, Staurastromy-cetaceae fam. nov.), Infecting the Freshwater Desmid Staurastrum sp.},
  series = {Protist},
  volume    = {168},
  journal   = {Protist},
  publisher = {Elsevier},
  address   = {Jena},
  issn      = {1434-4610},
  doi       = {10.1016/j.protis.2017.05.001},
  pages     = {392 -- 407},
  year      = {2017},
  abstract  = {Chytrids are a diverse group of ubiquitous true zoosporic fungi. The recent molecular discovery of a large diversity of undescribed chytrids has raised awareness on their important, but so far understudied ecological role in aquatic ecosystems. In the pelagic zone, of both freshwater and marine ecosystems, many chytrid species have been morphologically described as parasites on almost all major groups of phytoplankton. However, the majority of these parasitic chytrids has rarely been isolated and lack DNA sequence data, resulting in a large proportion of "dark taxa" in databases. Here, we report on the isolation and in-depth morphological, molecular and host range characterization of a chytrid infecting the common freshwater desmid Staurastrum sp. We provide first insights on the metabolic activity of the different chytrid development stages by using the vital dye FUN (R)-1 (2-chloro-4-[2,3-dihydro-3-methyl-[benzo-1,3-thiazol-2-yl]-methylidene]-1-phenylquinolinium iodide). Cross infection experiments suggest that this chytrid is an obligate parasite and specific for the genus Staurastrum sp. Phylogenetic analysis, based on ITS1-5.8S-ITS2 and 28S rDNA sequences, placed it in the order Rhizophydiales. Based on the unique zoospore ultrastructure, combined with thallus morphology, and molecular phylogenetic placement, we describe this parasitic chytrid as a new genus and species Staurastromyces oculus, within a new family Staurastromycetaceae. (C) 2017 Elsevier GmbH. All rights reserved.},
  language  = {en}
}
@article{VandenWyngaertRojasJimenezSetoetal.2018,
  author    = {Van den Wyngaert, Silke and Rojas-Jimenez, Keilor and Seto, Kensuke and Kagami, Maiko and Grossart, Hans-Peter},
  title     = {Diversity and Hidden Host Specificity of Chytrids Infecting Colonial Volvocacean Algae},
  series = {Journal of Eukaryotic Microbiology},
  volume    = {65},
  journal   = {Journal of Eukaryotic Microbiology},
  number    = {6},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {1066-5234},
  doi       = {10.1111/jeu.12632},
  pages     = {870 -- 881},
  year      = {2018},
  abstract  = {Chytrids are zoosporic fungi that play an important, but yet understudied, ecological role in aquatic ecosystems. Many chytrid species have been morphologically described as parasites on phytoplankton. However, the majority of them have rarely been isolated and lack DNA sequence data. In this study we isolated and cultivated three parasitic chytrids, infecting a common volvocacean host species, Yamagishiella unicocca. To identify the chytrids, we characterized morphology and life cycle, and analyzed phylogenetic relationships based on 18S and 28S rDNA genes. Host range and specificity of the chytrids was determined by cross-infection assays with host strains, characterized by rbcL and ITS markers. We were able to confirm the identity of two chytrid strains as Endocoenobium eudorinae Ingold and Dangeardia mamillata Schroder and described the third chytrid strain as Algomyces stechlinensis gen. et sp. nov. The three chytrids were assigned to novel and phylogenetically distant clades within the phylum Chytridiomycota, each exhibiting different host specificities. By integrating morphological and molecular data of both the parasitic chytrids and their respective host species, we unveiled cryptic host-parasite associations. This study highlights that a high prevalence of (pseudo)cryptic diversity requires molecular characterization of both phytoplankton host and parasitic chytrid to accurately identify and compare host range and specificity, and to study phytoplankton-chytrid interactions in general.},
  language  = {en}
}