TY - JOUR A1 - Fasching, Christina A1 - Akotoye, Christian A1 - Bižić, Mina A1 - Fonvielle, Jeremy Andre A1 - Ionescu, Danny A1 - Mathavarajah, Sabateeshan A1 - Zoccarato, Luca A1 - Walsh, David A. A1 - Grossart, Hans-Peter A1 - Xenopoulos, Marguerite A. T1 - Linking stream microbial community functional genes to dissolved organic matter and inorganic nutrients JF - Limnology and oceanography N2 - There is now increasing evidence for the importance of microbial regulation of biogeochemical cycling in streams. Resource availability shapes microbial community structure, but less is known about how landscape-mediated availability of nutrients and carbon can control microbial functions in streams. Using comparative metagenomics, we examined the relationship between microbial functional genes and composition of dissolved organic matter (DOM), nutrients, and suspended microbial communities in 11 streams, divided into three groups based on the predominant land cover category (agriculture, forested, or wetland). Using weighted gene co-occurrence network analysis, we identified clusters of functions related to DOM composition, agricultural land use, and/or wetland and forest land cover. Wetland-dominated streams were characterized by functions related to nitrogen metabolism and processing of aromatic carbon compounds, with strong positive correlations with dissolved organic carbon concentration and DOM aromaticity. Forested streams were characterized by metabolic functions related to monomer uptake and carbohydrates, such as mannose and fructose metabolism. In agricultural streams, microbial functions were correlated with more labile, protein-like DOM, PO4, and NO3, likely reflecting functional adaptation to labile DOM and higher nutrient concentrations. Distinct changes in the functional composition and loss of functional diversity of microorganisms became evident when comparing natural to agricultural catchments. Although all streams showed signs of functional redundancy, loss of species richness per function in agricultural catchments suggests that microbial functions in natural catchments may be more resilient to disturbance. Our results provide new insight into microbial community functions involved in nutrient and carbon biogeochemical cycles and their dependence on specific environmental settings. Y1 - 2019 U6 - https://doi.org/10.1002/lno.11356 SN - 0024-3590 SN - 1939-5590 VL - 65 SP - S71 EP - S87 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Bachmann, Jennifer A1 - Heimbach, Tabea A1 - Hassenrück, Christiane A1 - Kopprio, German A. A1 - Iversen, Morten Hvitfeldt A1 - Grossart, Hans-Peter A1 - Gärdes, Astrid T1 - Environmental Drivers of Free-Living vs. Particle-Attached Bacterial Community Composition in the Mauritania Upwelling System JF - Frontiers in microbiology N2 - Saharan dust input and seasonal upwelling along North-West Africa provide a model system for studying microbial processes related to the export and recycling of nutrients. This study offers the first molecular characterization of prokaryotic particle-attached (PA; > 3.0 mu m) and free-living (FL; 0.2-3.0 mu m) players in this important ecosystem during August 2016. Environmental drivers for alpha-diversity, bacterial community composition, and differences between FL and PA fractions were identified. The ultra-oligotrophic waters off Senegal were dominated by Cyanobacteria while higher relative abundances of Alphaproteobacteria, Bacteroidetes, Verrucomicrobia, and Planctomycetes (known particle-degraders) occurred in the upwelling area. Temperature, proxy for different water masses, was the best predictor for changes in FL communities. PA community variation was best explained by temperature and ammonium. Bray Curtis dissimilarities between FL and PA were generally very high and correlated with temperature and salinity in surface waters. Greatest similarities between FL and PA occurred at the deep chlorophyll maximum, where bacterial substrate availability was likely highest. This indicates that environmental drivers do not only influence changes among FL and PA communities but also differences between them. This could provide an explanation for contradicting results obtained by different studies regarding the dissimilarity/similarity between FL and PA communities and their biogeochemical functions. KW - prokaryotes KW - biodiversity KW - microbial ecology KW - alpha diversity KW - Bray Curtis dissimilarity KW - temperature KW - salinity KW - 16S rRNA Illumina amplicon sequencing Y1 - 2018 U6 - https://doi.org/10.3389/fmicb.2018.02836 SN - 1664-302X VL - 9 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Grossart, Hans-Peter A1 - Massana, Ramon A1 - McMahon, Katherine D. A1 - Walsh, David A. T1 - Linking metagenomics to aquatic microbial ecology and biogeochemical cycles JF - Limnology and oceanography N2 - Microbial communities are essential components of aquatic ecosystems through their contribution to food web dynamics and biogeochemical processes. Aquatic microbial diversity is immense and a general challenge is to understand how metabolism and interactions of single organisms shape microbial community dynamics and ecosystem-scale biogeochemical transformations. Metagenomic approaches have developed rapidly, and proven to be powerful in linking microbial community dynamics to biogeochemical processes. In this review, we provide an overview of metagenomic approaches, followed by a discussion on some recent insights they have provided, including those in this special issue. These include the discovery of new taxa and metabolisms in aquatic microbiomes, insights into community assembly and functional ecology as well as evolutionary processes shaping microbial genomes and microbiomes, and the influence of human activities on aquatic microbiomes. Given that metagenomics can now be considered a mature technology where data generation and descriptive analyses are relatively routine and informative, we then discuss metagenomic-enabled research avenues to further link microbial dynamics to biogeochemical processes. These include the integration of metagenomics into well-designed ecological experiments, the use of metagenomics to inform and validate metabolic and biogeochemical models, and the pressing need for ecologically relevant model organisms and simple microbial systems to better interpret the taxonomic and functional information integrated in metagenomes. These research avenues will contribute to a more mechanistic and predictive understanding of links between microbial dynamics and biogeochemical cycles. Owing to rapid climate change and human impacts on aquatic ecosystems, the urgency of such an understanding has never been greater. Y1 - 2019 U6 - https://doi.org/10.1002/lno.11382 SN - 0024-3590 SN - 1939-5590 VL - 65 SP - S2 EP - S20 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Van den Wyngaert, Silke A1 - Rojas-Jimenez, Keilor A1 - Seto, Kensuke A1 - Kagami, Maiko A1 - Grossart, Hans-Peter T1 - Diversity and Hidden Host Specificity of Chytrids Infecting Colonial Volvocacean Algae JF - Journal of Eukaryotic Microbiology N2 - 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. KW - Chytridiomycota KW - Dangeardia mamillata KW - Endocoenobium eudorinae KW - fungal parasites KW - life cycle KW - phytoplankton Y1 - 2018 U6 - https://doi.org/10.1111/jeu.12632 SN - 1066-5234 SN - 1550-7408 VL - 65 IS - 6 SP - 870 EP - 881 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Arias Andrés, María de Jesús A1 - Kettner, Marie Therese A1 - Miki, Takeshi A1 - Grossart, Hans-Peter T1 - Microplastics: New substrates for heterotrophic activity contribute to altering organic matter cycles in aquatic ecosystems JF - The science of the total environment : an international journal for scientific research into the environment and its relationship with man N2 - Heterotrophic microbes with the capability to process considerable amounts of organic matter can colonize microplastic particles (MP) in aquatic ecosystems. Weather colonization of microorganisms on MP will alter ecological niche and functioning of microbial communities remains still unanswered. Therefore, we compared the functional diversity of biofilms on microplastics when incubated in three lakes in northeastern Germany differing in trophy and limnological features. For all lakes, we compared heterotrophic activities of MP biofilms with those of microorganisms in the surrounding water by using Biolog (R) EcoPlates and assessed their oxygen consumption in microcosm assays with and without MP. The present study found that the total biofilm biomass was higher in the oligo-mesotrophic and dystrophic lakes than in the eutrophic lake. In all lakes, functional diversity profiles of MP biofilms consistently differed from those in the surrounding water. However, solely in the oligo-mesotrophic lake MP biofilms had a higher functional richness compared to the ambient water. These results demonstrate that the functionality and hence the ecological role of MP-associated microbial communities are context-dependent, i.e. different environments lead to substantial changes in biomass build up and heterotrophic activities of MP biofilms. We propose that MP surfaces act as new niches for aquatic microorganisms and that the constantly increasing MP pollution has the potential to globally impact carbon dynamics of pelagic environments by altering heterotrophic activities. (C) 2018 Elsevier B.V. All rights reserved. KW - Microplastics KW - Microorganisms KW - Biofilms KW - Total biomass KW - Heterotrophic activity KW - Functional diversity KW - Multi-functionality index Y1 - 2018 U6 - https://doi.org/10.1016/j.scitotenv.2018.04.199 SN - 0048-9697 SN - 1879-1026 VL - 635 SP - 1152 EP - 1159 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Bálint, Miklós A1 - Pfenninger, Markus A1 - Grossart, Hans-Peter A1 - Taberlet, Pierre A1 - Vellend, Mark A1 - Leibold, Mathew A. A1 - Englund, Goran A1 - Bowler, Diana T1 - Environmental DNA time series in ecology JF - Trends in ecology & evolution N2 - Ecological communities change in time and space, but long-term dynamics at the century-to-millennia scale are poorly documented due to lack of relevant data sets. Nevertheless, understanding long-term dynamics is important for explaining present-day biodiversity patterns and placing conservation goals in a historical context. Here, we use recent examples and new perspectives to highlight how environmental DNA (eDNA) is starting to provide a powerful new source of temporal data for research questions that have so far been overlooked, by helping to resolve the ecological dynamics of populations, communities, and ecosystems over hundreds to thousands of years. We give examples of hypotheses that may be addressed by temporal eDNA biodiversity data, discuss possible research directions, and outline related challenges. Y1 - 2018 U6 - https://doi.org/10.1016/j.tree.2018.09.003 SN - 0169-5347 SN - 1872-8383 VL - 33 IS - 12 SP - 945 EP - 957 PB - Elsevier CY - London ER - TY - JOUR A1 - Numberger, Daniela A1 - Riedel, Thomas A1 - McEwen, Gayle A1 - Nübel, Ulrich A1 - Frentrup, Martinique A1 - Schober, Isabel A1 - Bunk, Boyke A1 - Spröer, Cathrin A1 - Overmann, Jörg A1 - Grossart, Hans-Peter A1 - Greenwood, Alex D. T1 - Genomic analysis of three Clostridioides difficile isolates from urban water sources JF - Anaerobe N2 - We investigated inflow of a wastewater treatment plant and sediment of an urban lake for the presence of Clostridioides difficile by cultivation and PCR. Among seven colonies we sequenced the complete genomes of three: two non-toxigenic isolates from wastewater and one toxigenic isolate from the urban lake. For all obtained isolates, a close genomic relationship with human-derived isolates was observed. (C) 2019 Elsevier Ltd. All rights reserved. KW - Clostridioides difficile KW - Genomes KW - Sediment KW - Wastewater Y1 - 2019 U6 - https://doi.org/10.1016/j.anaerobe.2019.01.002 SN - 1075-9964 SN - 1095-8274 VL - 56 SP - 22 EP - 26 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Mantzouki, Evanthia A1 - Beklioglu, Meryem A1 - Brookes, Justin D. A1 - Domis, Lisette Nicole de Senerpont A1 - Dugan, Hilary A. A1 - Doubek, Jonathan P. A1 - Grossart, Hans-Peter A1 - Nejstgaard, Jens C. A1 - Pollard, Amina I. A1 - Ptacnik, Robert A1 - Rose, Kevin C. A1 - Sadro, Steven A1 - Seelen, Laura A1 - Skaff, Nicholas K. A1 - Teubner, Katrin A1 - Weyhenmeyer, Gesa A. A1 - Ibelings, Bastiaan W. T1 - Snapshot surveys for lake monitoring, more than a shot in the dark JF - Frontiers in Ecology and Evolution KW - multi-lake snapshot surveys KW - lake monitoring KW - Nyquist-shannon sampling theorem KW - space-for-time substitution KW - phytoplankton ecology Y1 - 2018 U6 - https://doi.org/10.3389/fevo.2018.00201 SN - 2296-701X VL - 6 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Mantzouki, Evanthia A1 - Campbell, James A1 - van Loon, Emiel A1 - Visser, Petra A1 - Konstantinou, Iosif A1 - Antoniou, Maria A1 - Giuliani, Gregory A1 - Machado-Vieira, Danielle A1 - de Oliveira, Alinne Gurjao A1 - Maronic, Dubravka Spoljaric A1 - Stevic, Filip A1 - Pfeiffer, Tanja Zuna A1 - Vucelic, Itana Bokan A1 - Zutinic, Petar A1 - Udovic, Marija Gligora A1 - Plenkovic-Moraj, Andelka A1 - Tsiarta, Nikoletta A1 - Blaha, Ludek A1 - Geris, Rodan A1 - Frankova, Marketa A1 - Christoffersen, Kirsten Seestern A1 - Warming, Trine Perlt A1 - Feldmann, Tonu A1 - Laas, Alo A1 - Panksep, Kristel A1 - Tuvikene, Lea A1 - Kangro, Kersti A1 - Haggqvist, Kerstin A1 - Salmi, Pauliina A1 - Arvola, Lauri A1 - Fastner, Jutta A1 - Straile, Dietmar A1 - Rothhaupt, Karl-Otto A1 - Fonvielle, Jeremy Andre A1 - Grossart, Hans-Peter A1 - Avagianos, Christos A1 - Kaloudis, Triantafyllos A1 - Triantis, Theodoros A1 - Zervou, Sevasti-Kiriaki A1 - Hiskia, Anastasia A1 - Gkelis, Spyros A1 - Panou, Manthos A1 - McCarthy, Valerie A1 - Perello, Victor C. A1 - Obertegger, Ulrike A1 - Boscaini, Adriano A1 - Flaim, Giovanna A1 - Salmaso, Nico A1 - Cerasino, Leonardo A1 - Koreiviene, Judita A1 - Karosiene, Jurate A1 - Kasperoviciene, Jurate A1 - Savadova, Ksenija A1 - Vitonyte, Irma A1 - Haande, Sigrid A1 - Skjelbred, Birger A1 - Grabowska, Magdalena A1 - Karpowicz, Maciej A1 - Chmura, Damian A1 - Nawrocka, Lidia A1 - Kobos, Justyna A1 - Mazur-Marzec, Hanna A1 - Alcaraz-Parraga, Pablo A1 - Wilk-Wozniak, Elzbieta A1 - Krzton, Wojciech A1 - Walusiak, Edward A1 - Gagala, Ilona A1 - Mankiewicz-Boczek, Joana A1 - Toporowska, Magdalena A1 - Pawlik-Skowronska, Barbara A1 - Niedzwiecki, Michal A1 - Peczula, Wojciech A1 - Napiorkowska-Krzebietke, Agnieszka A1 - Dunalska, Julita A1 - Sienska, Justyna A1 - Szymanski, Daniel A1 - Kruk, Marek A1 - Budzynska, Agnieszka A1 - Goldyn, Ryszard A1 - Kozak, Anna A1 - Rosinska, Joanna A1 - Szelag-Wasielewska, Elzbieta A1 - Domek, Piotr A1 - Jakubowska-Krepska, Natalia A1 - Kwasizur, Kinga A1 - Messyasz, Beata A1 - Pelechata, Aleksandra A1 - Pelechaty, Mariusz A1 - Kokocinski, Mikolaj A1 - Madrecka, Beata A1 - Kostrzewska-Szlakowska, Iwona A1 - Frak, Magdalena A1 - Bankowska-Sobczak, Agnieszka A1 - Wasilewicz, Michal A1 - Ochocka, Agnieszka A1 - Pasztaleniec, Agnieszka A1 - Jasser, Iwona A1 - Antao-Geraldes, Ana M. A1 - Leira, Manel A1 - Hernandez, Armand A1 - Vasconcelos, Vitor A1 - Morais, Joao A1 - Vale, Micaela A1 - Raposeiro, Pedro M. A1 - Goncalves, Vitor A1 - Aleksovski, Boris A1 - Krstic, Svetislav A1 - Nemova, Hana A1 - Drastichova, Iveta A1 - Chomova, Lucia A1 - Remec-Rekar, Spela A1 - Elersek, Tina A1 - Delgado-Martin, Jordi A1 - Garcia, David A1 - Luis Cereijo, Jose A1 - Goma, Joan A1 - Carmen Trapote, Mari A1 - Vegas-Vilarrubia, Teresa A1 - Obrador, Biel A1 - Garcia-Murcia, Ana A1 - Real, Monserrat A1 - Romans, Elvira A1 - Noguero-Ribes, Jordi A1 - Parreno Duque, David A1 - Fernandez-Moran, Elisabeth A1 - Ubeda, Barbara A1 - Angel Galvez, Jose A1 - Marce, Rafael A1 - Catalan, Nuria A1 - Perez-Martinez, Carmen A1 - Ramos-Rodriguez, Eloisa A1 - Cillero-Castro, Carmen A1 - Moreno-Ostos, Enrique A1 - Maria Blanco, Jose A1 - Rodriguez, Valeriano A1 - Juan Montes-Perez, Jorge A1 - Palomino, Roberto L. A1 - Rodriguez-Perez, Estela A1 - Carballeira, Rafael A1 - Camacho, Antonio A1 - Picazo, Antonio A1 - Rochera, Carlos A1 - Santamans, Anna C. A1 - Ferriol, Carmen A1 - Romo, Susana A1 - Soria, Juan Miguel A1 - Hansson, Lars-Anders A1 - Urrutia-Cordero, Pablo A1 - Ozen, Arda A1 - Bravo, Andrea G. A1 - Buck, Moritz A1 - Colom-Montero, William A1 - Mustonen, Kristiina A1 - Pierson, Don A1 - Yang, Yang A1 - Verspagen, Jolanda M. H. A1 - Domis, Lisette N. de Senerpont A1 - Seelen, Laura A1 - Teurlincx, Sven A1 - Verstijnen, Yvon A1 - Lurling, Miquel A1 - Maliaka, Valentini A1 - Faassen, Elisabeth J. A1 - Latour, Delphine A1 - Carey, Cayelan C. A1 - Paerl, Hans W. A1 - Torokne, Andrea A1 - Karan, Tunay A1 - Demir, Nilsun A1 - Beklioglu, Meryem A1 - Filiz, Nur A1 - Levi, Eti E. A1 - Iskin, Ugur A1 - Bezirci, Gizem A1 - Tavsanoglu, Ulku Nihan A1 - Celik, Kemal A1 - Ozhan, Koray A1 - Karakaya, Nusret A1 - Kocer, Mehmet Ali Turan A1 - Yilmaz, Mete A1 - Maraslioglu, Faruk A1 - Fakioglu, Ozden A1 - Soylu, Elif Neyran A1 - Yagci, Meral Apaydin A1 - Cinar, Sakir A1 - Capkin, Kadir A1 - Yagci, Abdulkadir A1 - Cesur, Mehmet A1 - Bilgin, Fuat A1 - Bulut, Cafer A1 - Uysal, Rahmi A1 - Koker, Latife A1 - Akcaalan, Reyhan A1 - Albay, Meric A1 - Alp, Mehmet Tahir A1 - Ozkan, Korhan A1 - Sevindik, Tugba Ongun A1 - Tunca, Hatice A1 - Onem, Burcin A1 - Richardson, Jessica A1 - Edwards, Christine A1 - Bergkemper, Victoria A1 - Beirne, Eilish A1 - Cromie, Hannah A1 - Ibelings, Bastiaan W. T1 - Data Descriptor: A European Multi Lake Survey dataset of environmental variables, phytoplankton pigments and cyanotoxins JF - Scientific Data N2 - Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent problem resulting from nutrient pollution and climate-change induced stressors, like poor transparency, increased water temperature and enhanced stratification. Consistency in data collection and analysis methods is necessary to achieve fully comparable datasets and for statistical validity, avoiding issues linked to disparate data sources. The European Multi Lake Survey (EMLS) in summer 2015 was an initiative among scientists from 27 countries to collect and analyse lake physical, chemical and biological variables in a fully standardized manner. This database includes in-situ lake variables along with nutrient, pigment and cyanotoxin data of 369 lakes in Europe, which were centrally analysed in dedicated laboratories. Publishing the EMLS methods and dataset might inspire similar initiatives to study across large geographic areas that will contribute to better understanding lake responses in a changing environment. KW - Climate-change ecology KW - Limnology KW - Water resources Y1 - 2018 U6 - https://doi.org/10.1038/sdata.2018.226 SN - 2052-4463 VL - 5 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Darwall, William A1 - Bremerich, Vanessa A1 - De Wever, Aaike A1 - Dell, Anthony I. A1 - Freyhof, Joerg A1 - Gessner, Mark O. A1 - Grossart, Hans-Peter A1 - Harrison, Ian A1 - Irvine, Ken A1 - Jähnig, Sonja C. A1 - Jeschke, Jonathan M. A1 - Lee, Jessica J. A1 - Lu, Cai A1 - Lewandowska, Aleksandra M. A1 - Monaghan, Michael T. A1 - Nejstgaard, Jens C. A1 - Patricio, Harmony A1 - Schmidt-Kloiber, Astrid A1 - Stuart, Simon N. A1 - Thieme, Michele A1 - Tockner, Klement A1 - Turak, Eren A1 - Weyl, Olaf T1 - The alliance for freshwater life BT - a global call to unite efforts for freshwater biodiversity science and conservation JF - Aquatic Conservation: Marine and Freshwater Ecosystems N2 - 1. Global pressures on freshwater ecosystems are high and rising. Viewed primarily as a resource for humans, current practices of water use have led to catastrophic declines in freshwater species and the degradation of freshwater ecosystems, including their genetic and functional diversity. Approximately three-quarters of the world's inland wetlands have been lost, one-third of the 28 000 freshwater species assessed for the International Union for Conservation of Nature (IUCN) Red List are threatened with extinction, and freshwater vertebrate populations are undergoing declines that are more rapid than those of terrestrial and marine species. This global loss continues unchecked, despite the importance of freshwater ecosystems as a source of clean water, food, livelihoods, recreation, and inspiration. 2. The causes of these declines include hydrological alterations, habitat degradation and loss, overexploitation, invasive species, pollution, and the multiple impacts of climate change. Although there are policy initiatives that aim to protect freshwater life, these are rarely implemented with sufficient conviction and enforcement. Policies that focus on the development and management of fresh waters as a resource for people almost universally neglect the biodiversity that they contain. 3. Here we introduce the Alliance for Freshwater Life, a global initiative, uniting specialists in research, data synthesis, conservation, education and outreach, and policymaking. This expert network aims to provide the critical mass required for the effective representation of freshwater biodiversity at policy meetings, to develop solutions balancing the needs of development and conservation, and to better convey the important role freshwater ecosystems play in human well-being. Through this united effort we hope to reverse this tide of loss and decline in freshwater biodiversity. We introduce several short- and medium-term actions as examples for making positive change, and invite individuals, organizations, authorities, and governments to join the Alliance for Freshwater Life. KW - biodiversity KW - conservation evaluation KW - endangered species KW - fish KW - invertebrates KW - macrophytes Y1 - 2018 U6 - https://doi.org/10.1002/aqc.2958 SN - 1052-7613 SN - 1099-0755 VL - 28 IS - 4 SP - 1015 EP - 1022 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Wurzbacher, Christian A1 - Fuchs, Andrea A1 - Attermeyer, Katrin A1 - Frindte, Katharina A1 - Grossart, Hans-Peter A1 - Hupfer, Michael A1 - Casper, Peter A1 - Monaghan, Michael T. T1 - Shifts among Eukaryota, Bacteria, and Archaea define the vertical organization of a lake sediment JF - Microbiome N2 - 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. KW - Archaea KW - Eukaryota KW - Bacteria KW - Community KW - Freshwater KW - Lake KW - DNA metabarcoding KW - Beta-diversity KW - Sediment KW - Turnover Y1 - 2017 U6 - https://doi.org/10.1186/s40168-017-0255-9 SN - 2049-2618 VL - 5 PB - BioMed Central CY - London ER - TY - JOUR A1 - Göritz, Anna A1 - Berger, Stella A. A1 - Gege, Peter A1 - Grossart, Hans-Peter A1 - Nejstgaard, Jens C. A1 - Riedel, Sebastian A1 - Röttgers, Rüdiger A1 - Utschig, Christian T1 - Retrieval of water constituents from hyperspectral in-situ measurements under variable cloud cover BT - a case study at Lake Stechlin (Germany) JF - Remote sensing / Molecular Diversity Preservation International (MDPI) N2 - Remote sensing and field spectroscopy of natural waters is typically performed under clear skies, low wind speeds and low solar zenith angles. Such measurements can also be made, in principle, under clouds and mixed skies using airborne or in-situ measurements; however, variable illumination conditions pose a challenge to data analysis. In the present case study, we evaluated the inversion of hyperspectral in-situ measurements for water constituent retrieval acquired under variable cloud cover. First, we studied the retrieval of Chlorophyll-a (Chl-a) concentration and colored dissolved organic matter (CDOM) absorption from in-water irradiance measurements. Then, we evaluated the errors in the retrievals of the concentration of total suspended matter (TSM), Chl-a and the absorption coefficient of CDOM from above-water reflectance measurements due to highly variable reflections at the water surface. In order to approximate cloud reflections, we extended a recent three-component surface reflectance model for cloudless atmospheres by a constant offset and compared different surface reflectance correction procedures. Our findings suggest that in-water irradiance measurements may be used for the analysis of absorbing compounds even under highly variable weather conditions. The extended surface reflectance model proved to contribute to the analysis of above-water reflectance measurements with respect to Chl-a and TSM. Results indicate the potential of this approach for all-weather monitoring. KW - remote sensing KW - inland water KW - hyperspectral measurements KW - in-situ KW - cloud KW - surface reflection KW - inversion KW - bio-optical modeling Y1 - 2018 U6 - https://doi.org/10.3390/rs10020181 SN - 2072-4292 VL - 10 IS - 2 PB - MDPI CY - Basel ER - TY - JOUR A1 - Cuadrat, Rafael R. C. A1 - Ionescu, Danny A1 - Davila, Alberto M. R. A1 - Grossart, Hans-Peter T1 - Recovering genomics clusters of secondary metabolites from lakes using genome-resolved metagenomics JF - Frontiers in microbiology N2 - Metagenomic approaches became increasingly popular in the past decades due to decreasing costs of DNA sequencing and bioinformatics development. So far, however, the recovery of long genes coding for secondary metabolites still represents a big challenge. Often, the quality of metagenome assemblies is poor, especially in environments with a high microbial diversity where sequence coverage is low and complexity of natural communities high. Recently, new and improved algorithms for binning environmental reads and contigs have been developed to overcome such limitations. Some of these algorithms use a similarity detection approach to classify the obtained reads into taxonomical units and to assemble draft genomes. This approach, however, is quite limited since it can classify exclusively sequences similar to those available (and well classified) in the databases. In this work, we used draft genomes from Lake Stechlin, north-eastern Germany, recovered by MetaBat, an efficient binning tool that integrates empirical probabilistic distances of genome abundance, and tetranucleotide frequency for accurate metagenome binning. These genomes were screened for secondary metabolism genes, such as polyketide synthases (PKS) and non-ribosomal peptide synthases (NRPS), using the Anti-SMASH and NAPDOS workflows. With this approach we were able to identify 243 secondary metabolite clusters from 121 genomes recovered from our lake samples. A total of 18 NRPS, 19 PKS, and 3 hybrid PKS/NRPS clusters were found. In addition, it was possible to predict the partial structure of several secondary metabolite clusters allowing for taxonomical classifications and phylogenetic inferences. Our approach revealed a high potential to recover and study secondary metabolites genes from any aquatic ecosystem. KW - metagenomics 2.0 KW - PKS KW - NRPS KW - freshwater KW - environmental genomics Y1 - 2018 U6 - https://doi.org/10.3389/fmicb.2018.00251 SN - 1664-302X VL - 9 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Weyhenmeyer, Gesa A. A1 - Mackay, Murray A1 - Stockwell, Jason D. A1 - Thiery, Wim A1 - Grossart, Hans-Peter A1 - Augusto-Silva, Petala B. A1 - Baulch, Helen M. A1 - de Eyto, Elvira A1 - Hejzlar, Josef A1 - Kangur, Kuelli A1 - Kirillin, Georgiy A1 - Pierson, Don C. A1 - Rusak, James A. A1 - Sadro, Steven A1 - Woolway, R. Iestyn T1 - Citizen science shows systematic changes in the temperature difference between air and inland waters with global warming JF - Scientific reports N2 - Citizen science projects have a long history in ecological studies. The research usefulness of such projects is dependent on applying simple and standardized methods. Here, we conducted a citizen science project that involved more than 3500 Swedish high school students to examine the temperature difference between surface water and the overlying air (T-w-T-a) as a proxy for sensible heat flux (Q(H)). If Q(H) is directed upward, corresponding to positive T-w-T-a, it can enhance CO2 and CH4 emissions from inland waters, thereby contributing to increased greenhouse gas concentrations in the atmosphere. The students found mostly negative T-w-T-a across small ponds, lakes, streams/rivers and the sea shore (i.e. downward Q(H)), with T-w-T-a becoming increasingly negative with increasing T-a. Further examination of T-w-T-a using high-frequency temperature data from inland waters across the globe confirmed that T-w-T-a is linearly related to T-a. Using the longest available high-frequency temperature time series from Lake Erken, Sweden, we found a rapid increase in the occasions of negative T-w-T-a with increasing annual mean T-a since 1989. From these results, we can expect that ongoing and projected global warming will result in increasingly negative T-w-T-a, thereby reducing CO2 and CH4 transfer velocities from inland waters into the atmosphere. Y1 - 2017 U6 - https://doi.org/10.1038/srep43890 SN - 2045-2322 VL - 7 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - McGinnis, Daniel F. A1 - Flury, Sabine A1 - Tang, Kam W. A1 - Grossart, Hans-Peter T1 - Porewater methane transport within the gas vesicles of diurnally migrating Chaoborus spp. BT - an energetic advantage JF - Scientific reports N2 - Diurnally-migrating Chaoborus spp. reach populations of up to 130,000 individuals m−2 in lakes up to 70 meters deep on all continents except Antarctica. Linked to eutrophication, migrating Chaoborus spp. dwell in the anoxic sediment during daytime and feed in the oxic surface layer at night. Our experiments show that by burrowing into the sediment, Chaoborus spp. utilize the high dissolved gas partial pressure of sediment methane to inflate their tracheal sacs. This mechanism provides a significant energetic advantage that allows the larvae to migrate via passive buoyancy rather than more energy-costly swimming. The Chaoborus spp. larvae, in addition to potentially releasing sediment methane bubbles twice a day by entering and leaving the sediment, also transport porewater methane within their gas vesicles into the water column, resulting in a flux of 0.01–2 mol m−2 yr−1 depending on population density and water depth. Chaoborus spp. emerging annually as flies also result in 0.1–6 mol m−2 yr−1 of carbon export from the system. Finding the tipping point in lake eutrophication enabling this methane-powered migration mechanism is crucial for ultimately reconstructing the geographical expansion of Chaoborus spp., and the corresponding shifts in the lake’s biogeochemistry, carbon cycling and food web structure. Y1 - 2017 U6 - https://doi.org/10.1038/srep44478 SN - 2045-2322 VL - 7 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Ionescu, Danny A1 - Bizic, Mina A1 - Karnatak, Rajat A1 - Musseau, Camille L. A1 - Onandia, Gabriela A1 - Kasada, Minoru A1 - Berger, Stella A. A1 - Nejstgaard, Jens Christian A1 - Ryo, Masahiro A1 - Lischeid, Gunnar A1 - Gessner, Mark O. A1 - Wollrab, Sabine A1 - Grossart, Hans-Peter T1 - From microbes to mammals: Pond biodiversity homogenization across different land-use types in an agricultural landscape JF - Ecological monographs N2 - Local biodiversity patterns are expected to strongly reflect variation in topography, land use, dispersal boundaries, nutrient supplies, contaminant spread, management practices, and other anthropogenic influences. Contrary to this expectation, studies focusing on specific taxa revealed a biodiversity homogenization effect in areas subjected to long-term intensive industrial agriculture. We investigated whether land use affects biodiversity levels and community composition (alpha- and beta-diversity) in 67 kettle holes (KH) representing small aquatic islands embedded in the patchwork matrix of a largely agricultural landscape comprising grassland, forest, and arable fields. These KH, similar to millions of standing water bodies of glacial origin, spread across northern Europe, Asia, and North America, are physico-chemically diverse and differ in the degree of coupling with their surroundings. We assessed aquatic and sediment biodiversity patterns of eukaryotes, Bacteria, and Archaea in relation to environmental features of the KH, using deep-amplicon-sequencing of environmental DNA (eDNA). First, we asked whether deep sequencing of eDNA provides a representative picture of KH aquatic biodiversity across the Bacteria, Archaea, and eukaryotes. Second, we investigated if and to what extent KH biodiversity is influenced by the surrounding land use. We hypothesized that richness and community composition will greatly differ in KH from agricultural land use compared with KH in grasslands and forests. Our data show that deep eDNA amplicon sequencing is useful for in-depth assessments of cross-domain biodiversity comprising both micro- and macro-organisms, but has limitations with respect to single-taxa conservation studies. Using this broad method, we show that sediment eDNA, integrating several years to decades, depicts the history of agricultural land-use intensification. Aquatic biodiversity was best explained by seasonality, whereas land-use type explained little of the variation. We concluded that, counter to our hypothesis, land use intensification coupled with landscape wide nutrient enrichment (including atmospheric deposition), groundwater connectivity between KH and organismal (active and passive) dispersal in the tight network of ponds, resulted in a biodiversity homogenization in the KH water, leveling off today's detectable differences in KH biodiversity between land-use types. These findings have profound implications for measures and management strategies to combat current biodiversity loss in agricultural landscapes worldwide. KW - biodiversity homogenization KW - eDNA KW - intensive agriculture KW - kettle hole; KW - land use Y1 - 2022 U6 - https://doi.org/10.1002/ecm.1523 SN - 0012-9615 SN - 1557-7015 VL - 92 IS - 3 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Hornick, Thomas A1 - Bach, Lennart T. A1 - Crawfurd, Katharine J. A1 - Spilling, Kristian A1 - Achterberg, Eric P. A1 - Woodhouse, Jason Nicholas A1 - Schulz, Kai G. A1 - Brussaard, Corina P. D. A1 - Riebesell, Ulf A1 - Grossart, Hans-Peter T1 - Ocean acidification impacts bacteria-phytoplankton coupling at low-nutrient conditions JF - Biogeosciences N2 - The oceans absorb about a quarter of the annually produced anthropogenic atmospheric carbon dioxide (CO2), resulting in a decrease in surface water pH, a process termed ocean acidification (OA). Surprisingly little is known about how OA affects the physiology of heterotrophic bacteria or the coupling of heterotrophic bacteria to phytoplankton when nutrients are limited. Previous experiments were, for the most part, undertaken during productive phases or following nutrient additions designed to stimulate algal blooms. Therefore, we performed an in situ large-volume mesocosm (similar to 55 m(3)) experiment in the Baltic Sea by simulating different fugacities of CO2 (fCO(2)) extending from present to future conditions. The study was conducted in July-August after the nominal spring bloom, in order to maintain low-nutrient conditions throughout the experiment. This resulted in phytoplankton communities dominated by small-sized functional groups (picophytoplankton). There was no consistent fCO(2)-induced effect on bacterial protein production (BPP), cell-specific BPP (csBPP) or biovolumes (BVs) of either free-living (FL) or particle-associated (PA) heterotrophic bacteria, when considered as individual components (univariate analyses). Permutational Multivariate Analysis of Variance (PERMANOVA) revealed a significant effect of the fCO(2) treatment on entire assemblages of dissolved and particulate nutrients, metabolic parameters and the bacteria-phytoplankton community. However, distance-based linear modelling only identified fCO(2) as a factor explaining the variability observed amongst the microbial community composition, but not for explaining variability within the metabolic parameters. This suggests that fCO(2) impacts on microbial metabolic parameters occurred indirectly through varying physicochemical parameters and microbial species composition. Cluster analyses examining the co-occurrence of different functional groups of bacteria and phytoplankton further revealed a separation of the four fCO(2)-treated mesocosms from both control mesocosms, indicating that complex trophic interactions might be altered in a future acidified ocean. Possible consequences for nutrient cycling and carbon export are still largely unknown, in particular in a nutrient-limited ocean. Y1 - 2017 U6 - https://doi.org/10.5194/bg-14-1-2017 SN - 1726-4170 SN - 1726-4189 VL - 14 IS - 1 SP - 1 EP - 15 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Xiao, Shangbin A1 - Liu, Liu A1 - Wang, Wei A1 - Lorke, Andreas A1 - Woodhouse, Jason Nicholas A1 - Grossart, Hans-Peter T1 - A Fast-Response Automated Gas Equilibrator (FaRAGE) for continuous in situ measurement of CH4 and CO2 dissolved in water JF - Hydrology and earth system sciences : HESS N2 - Biogenic greenhouse gas emissions, e.g., of methane (CH4) and carbon dioxide (CO2) from inland waters, contribute substantially to global warming. In aquatic systems, dissolved greenhouse gases are highly heterogeneous in both space and time. To better understand the biological and physical processes that affect sources and sinks of both CH4 and CO2, their dissolved concentrations need to be measured with high spatial and temporal resolution. To achieve this goal, we developed the Fast-Response Automated Gas Equilibrator (FaRAGE) for real-time in situ measurement of dissolved CH4 and CO2 concentrations at the water surface and in the water column. FaRAGE can achieve an exceptionally short response time (t(95%) = 12 s when including the response time of the gas analyzer) while retaining an equilibration ratio of 62.6% and a measurement accuracy of 0.5% for CH4. A similar performance was observed for dissolved CO2 (t(95%) = 10 s, equilibration ratio 67.1 %). An equilibration ratio as high as 91.8% can be reached at the cost of a slightly increased response time (16 s). The FaRAGE is capable of continuously measuring dissolved CO2 and CH4 concentrations in the nM-to-submM (10(-9)-10(-3) mol L-1) range with a detection limit of subnM (10(-10) mol L-1), when coupling with a cavity ring-down greenhouse gas analyzer (Picarro GasScouter). FaRAGE allows for the possibility of mapping dissolved concentration in a "quasi" three-dimensional manner in lakes and provides an inexpensive alternative to other commercial gas equilibrators. It is simple to operate and suitable for continuous monitoring with a strong tolerance for suspended particles. While the FaRAGE is developed for inland waters, it can be also applied to ocean waters by tuning the gas-water mixing ratio. The FaRAGE is easily adapted to suit other gas analyzers expanding the range of potential applications, including nitrous oxide and isotopic composition of the gases. Y1 - 2020 U6 - https://doi.org/10.5194/hess-24-3871-2020 SN - 1027-5606 SN - 1607-7938 VL - 24 IS - 7 SP - 3871 EP - 3880 PB - European Geosciences Union (EGU) ; Copernicus CY - Munich ER - TY - JOUR A1 - Hoke, Alexa A1 - Woodhouse, Jason Nicholas A1 - Zoccarato, Luca A1 - McCarthy, Valerie A1 - de Eyto, Elvira A1 - Caldero-Pascual, Maria A1 - Geffroy, Ewan A1 - Dillane, Mary A1 - Grossart, Hans-Peter A1 - Jennings, Eleanor T1 - Impacts of extreme weather events on bacterial community composition of a temperate humic lake JF - Water N2 - Extreme weather events are projected to increase in frequency and intensity as climate change continues. Heterotrophic bacteria play a critical role in lake ecosystems, yet little research has been done to determine how they are affected by such extremes. The purpose of this study was to use high-throughput sequencing to explore the bacterial community composition of a humic oligotrophic lake on the North Atlantic Irish coast and to assess the impacts on composition dynamics related to extreme weather events. Samples for sequencing were collected from Lough Feeagh on a fortnightly basis from April to November 2018. Filtration was used to separate free-living and particle-associated bacterial communities and amplicon sequencing was performed for the 16S rRNA V4 region. Two named storms, six high discharge events, and one drought period occurred during the sampling period. These events had variable, context-dependent effects on bacterial communities in Lough Feeagh. The particle-associated community was found to be more likely to respond to physical changes, such as mixing, while the free-living population responded to changes in nutrient and carbon concentrations. Generally, however, the high stability of the bacterial community observed in Lough Feeagh suggests that the bacterial community is relatively resilient to extreme weather events. KW - extreme weather event KW - storm KW - drought KW - bacteria KW - free-living KW - particle-associated KW - humic lake Y1 - 2020 U6 - https://doi.org/10.3390/w12102757 SN - 2073-4441 VL - 12 IS - 10 PB - MDPI CY - Basel ER - TY - JOUR A1 - Schellenberg, Johannes A1 - Reichert, Jessica A1 - Hardt, Martin A1 - Klingelhöfer, Ines A1 - Morlock, Gertrud A1 - Schubert, Patrick A1 - Bižić, Mina A1 - Grossart, Hans-Peter A1 - Kämpfer, Peter A1 - Wilke, Thomas A1 - Glaeser, Stefanie P. T1 - The bacterial microbiome of the long-term aquarium cultured high-microbial abundance sponge Haliclona cnidata BT - sustained bioactivity despite community shifts under detrimental conditions JF - Frontiers in Marine Science N2 - Marine sponges host highly diverse but specific bacterial communities that provide essential functions for the sponge holobiont, including antimicrobial defense. Here, we characterized the bacterial microbiome of the marine sponge Haliclona cnidata that has been in culture in an artificial marine aquarium system. We tested the hypotheses (1) that the long-term aquarium cultured sponge H. cnidata is tightly associated with a typical sponge bacterial microbiota and (2) that the symbiotic Bacteria sustain bioactivity under harmful environmental conditions to facilitate holobiont survival by preventing pathogen invasion. Microscopic and phylogenetic analyses of the bacterial microbiota revealed that H. cnidata represents a high microbial abundance (HMA) sponge with a temporally stable bacterial community that significantly shifts with changing aquarium conditions. A 4-week incubation experiment was performed in small closed aquarium systems with antibiotic and/or light exclusion treatments to reduce the total bacterial and photosynthetically active sponge-associated microbiota to a treatment-specific resilient community. While the holobiont was severely affected by the experimental treatment (i.e., bleaching of the sponge, reduced bacterial abundance, shifted bacterial community composition), the biological defense and bacterial community interactions (i.e., quorum sensing activity) remained intact. 16S rRNA gene amplicon sequencing revealed a resilient community of 105 bacterial taxa, which remained in the treated sponges. These 105 taxa accounted for a relative abundance of 72-83% of the bacterial sponge microbiota of non-treated sponge fragments that have been cultured under the same conditions. We conclude that a sponge-specific resilient community stays biologically active under harmful environmental conditions, facilitating the resilience of the holobiont. In H. cnidata, bacteria are located in bacteriocytes, which may have contributed to the observed phenomenon. KW - HMA sponge KW - bacterial symbionts KW - holobiont KW - antimicrobial defense KW - quorum sensing KW - bacteriocytes Y1 - 2020 U6 - https://doi.org/10.3389/fmars.2020.00266 SN - 2296-7745 VL - 7 PB - Frontiers Media CY - Lausanne ER -