TY  - JOUR
A1  - Balint, Miklos
A1  - Marton, Orsolya
A1  - Schatz, Marlene
A1  - Düring, Rolf-Alexander
A1  - Grossart, Hans-Peter
T1  - Proper experimental design requires randomization/balancing of molecular ecology experiments
JF  - Ecology and evolution
N2  - Properly designed (randomized and/or balanced) experiments are standard in ecological research. Molecular methods are increasingly used in ecology, but studies generally do not report the detailed design of sample processing in the laboratory. This may strongly influence the interpretability of results if the laboratory procedures do not account for the confounding effects of unexpected laboratory events. We demonstrate this with a simple experiment where unexpected differences in laboratory processing of samples would have biased results if randomization in DNA extraction and PCR steps do not provide safeguards. We emphasize the need for proper experimental design and reporting of the laboratory phase of molecular ecology research to ensure the reliability and interpretability of results.
KW  - batch effect
KW  - bias
KW  - DNA extraction
KW  - environmental DNA
KW  - laboratory practice
KW  - lake community
KW  - metabarcoding
KW  - nondemonic intrusions
KW  - PCR
KW  - sediment
Y1  - 2018
U6  - https://doi.org/10.1002/ece3.3687
SN  - 2045-7758
VL  - 8
IS  - 3
SP  - 1786
EP  - 1793
PB  - Wiley
CY  - Hoboken
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  - Leach, Taylor H.
A1  - Beisner, Beatrix E.
A1  - Carey, Cayelan C.
A1  - Pernica, Patricia
A1  - Rose, Kevin C.
A1  - Huot, Yannick
A1  - Brentrup, Jennifer A.
A1  - Domaizon, Isabelle
A1  - Grossart, Hans-Peter
A1  - Ibelings, Bastiaan W.
A1  - Jacquet, Stephan
A1  - Kelly, Patrick T.
A1  - Rusak, James A.
A1  - Stockwell, Jason D.
A1  - Straile, Dietmar
A1  - Verburg, Piet
T1  - Patterns and drivers of deep chlorophyll maxima structure in 100 lakes
BT  - the relative importance of light and thermal stratification
JF  - Limnology and oceanography
N2  - The vertical distribution of chlorophyll in stratified lakes and reservoirs frequently exhibits a maximum peak deep in the water column, referred to as the deep chlorophyll maximum (DCM). DCMs are ecologically important hot spots of primary production and nutrient cycling, and their location can determine vertical habitat gradients for primary consumers. Consequently, the drivers of DCM structure regulate many characteristics of aquatic food webs and biogeochemistry. Previous studies have identified light and thermal stratification as important drivers of summer DCM depth, but their relative importance across a broad range of lakes is not well resolved. We analyzed profiles of chlorophyll fluorescence, temperature, and light during summer stratification from 100 lakes in the Global Lake Ecological Observatory Network (GLEON) and quantified two characteristics of DCM structure: depth and thickness. While DCMs do form in oligotrophic lakes, we found that they can also form in eutrophic to dystrophic lakes. Using a random forest algorithm, we assessed the relative importance of variables associated with light attenuation vs. thermal stratification for predicting DCM structure in lakes that spanned broad gradients of morphometry and transparency. Our analyses revealed that light attenuation was a more important predictor of DCM depth than thermal stratification and that DCMs deepen with increasing lake clarity. DCM thickness was best predicted by lake size with larger lakes having thicker DCMs. Additionally, our analysis demonstrates that the relative importance of light and thermal stratification on DCM structure is not uniform across a diversity of lake types.
Y1  - 2018
U6  - https://doi.org/10.1002/lno.10656
SN  - 0024-3590
SN  - 1939-5590
VL  - 63
IS  - 2
SP  - 628
EP  - 646
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Schulze-Makuch, Dirk
A1  - Wagner, Dirk
A1  - Kounaves, Samuel P.
A1  - Mangelsdorf, Kai
A1  - Devine, Kevin G.
A1  - de Vera, Jean-Pierre
A1  - Schmitt-Kopplin, Philippe
A1  - Grossart, Hans-Peter
A1  - Parro, Victor
A1  - Kaupenjohann, Martin
A1  - Galy, Albert
A1  - Schneider, Beate
A1  - Airo, Alessandro
A1  - Froesler, Jan
A1  - Davila, Alfonso F.
A1  - Arens, Felix L.
A1  - Caceres, Luis
A1  - Cornejo, Francisco Solis
A1  - Carrizo, Daniel
A1  - Dartnell, Lewis
A1  - DiRuggiero, Jocelyne
A1  - Flury, Markus
A1  - Ganzert, Lars
A1  - Gessner, Mark O.
A1  - Grathwohl, Peter
A1  - Guan, Lisa
A1  - Heinz, Jacob
A1  - Hess, Matthias
A1  - Keppler, Frank
A1  - Maus, Deborah
A1  - McKay, Christopher P.
A1  - Meckenstock, Rainer U.
A1  - Montgomery, Wren
A1  - Oberlin, Elizabeth A.
A1  - Probst, Alexander J.
A1  - Saenz, Johan S.
A1  - Sattler, Tobias
A1  - Schirmack, Janosch
A1  - Sephton, Mark A.
A1  - Schloter, Michael
A1  - Uhl, Jenny
A1  - Valenzuela, Bernardita
A1  - Vestergaard, Gisle
A1  - Woermer, Lars
A1  - Zamorano, Pedro
T1  - Transitory microbial habitat in the hyperarid Atacama Desert
JF  - Proceedings of the National Academy of Sciences of the United States of America
KW  - habitat
KW  - aridity
KW  - microbial activity
KW  - biomarker
KW  - Mars
Y1  - 2018
U6  - https://doi.org/10.1073/pnas.1714341115
SN  - 0027-8424
VL  - 115
IS  - 11
SP  - 2670
EP  - 2675
PB  - National Acad. of Sciences
CY  - Washington
ER  - 
TY  - JOUR
A1  - Mantzouki, Evanthia
A1  - Lurling, Miquel
A1  - Fastner, Jutta
A1  - Domis, Lisette Nicole de Senerpont
A1  - Wilk-Wozniak, Elzbieta
A1  - Koreiviene, Judita
A1  - Seelen, Laura
A1  - Teurlincx, Sven
A1  - Verstijnen, Yvon
A1  - Krzton, Wojciech
A1  - Walusiak, Edward
A1  - Karosiene, Jurate
A1  - Kasperoviciene, Jurate
A1  - Savadova, Ksenija
A1  - Vitonyte, Irma
A1  - Cillero-Castro, Carmen
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  - Garcia-Murcia, Ana
A1  - Real, Monserrat
A1  - Romans, Elvira
A1  - Noguero-Ribes, Jordi
A1  - Parreno Duque, David
A1  - Fernandez-Moran, Elisabeth
A1  - Karakaya, Nusret
A1  - Haggqvist, Kerstin
A1  - Demir, Nilsun
A1  - Beklioglu, Meryem
A1  - Filiz, Nur
A1  - Levi, Eti E.
A1  - Iskin, Ugur
A1  - Bezirci, Gizem
A1  - Tavsanoglu, Ulku Nihan
A1  - Ozhan, Koray
A1  - Gkelis, Spyros
A1  - Panou, Manthos
A1  - Fakioglu, Ozden
A1  - Avagianos, Christos
A1  - Kaloudis, Triantafyllos
A1  - Celik, Kemal
A1  - Yilmaz, Mete
A1  - Marce, Rafael
A1  - Catalan, Nuria
A1  - Bravo, Andrea G.
A1  - Buck, Moritz
A1  - Colom-Montero, William
A1  - Mustonen, Kristiina
A1  - Pierson, Don
A1  - Yang, Yang
A1  - Raposeiro, Pedro M.
A1  - Goncalves, Vitor
A1  - Antoniou, Maria G.
A1  - Tsiarta, Nikoletta
A1  - McCarthy, Valerie
A1  - Perello, Victor C.
A1  - Feldmann, Tonu
A1  - Laas, Alo
A1  - Panksep, Kristel
A1  - Tuvikene, Lea
A1  - Gagala, Ilona
A1  - Mankiewicz-Boczek, Joana
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  - Obertegger, Ulrike
A1  - Boscaini, Adriano
A1  - Flaim, Giovanna
A1  - Salmaso, Nico
A1  - Cerasino, Leonardo
A1  - Richardson, Jessica
A1  - Visser, Petra M.
A1  - Verspagen, Jolanda M. H.
A1  - Karan, Tunay
A1  - Soylu, Elif Neyran
A1  - Maraslioglu, Faruk
A1  - Napiorkowska-Krzebietke, Agnieszka
A1  - Ochocka, Agnieszka
A1  - Pasztaleniec, Agnieszka
A1  - Antao-Geraldes, Ana M.
A1  - Vasconcelos, Vitor
A1  - Morais, Joao
A1  - Vale, Micaela
A1  - Koker, Latife
A1  - Akcaalan, Reyhan
A1  - Albay, Meric
A1  - Maronic, Dubravka Spoljaric
A1  - Stevic, Filip
A1  - Pfeiffer, Tanja Zuna
A1  - Fonvielle, Jeremy Andre
A1  - Straile, Dietmar
A1  - Rothhaupt, Karl-Otto
A1  - Hansson, Lars-Anders
A1  - Urrutia-Cordero, Pablo
A1  - Blaha, Ludek
A1  - Geris, Rodan
A1  - Frankova, Marketa
A1  - Kocer, Mehmet Ali Turan
A1  - Alp, Mehmet Tahir
A1  - Remec-Rekar, Spela
A1  - Elersek, Tina
A1  - Triantis, Theodoros
A1  - Zervou, Sevasti-Kiriaki
A1  - Hiskia, Anastasia
A1  - Haande, Sigrid
A1  - Skjelbred, Birger
A1  - Madrecka, Beata
A1  - Nemova, Hana
A1  - Drastichova, Iveta
A1  - Chomova, Lucia
A1  - Edwards, Christine
A1  - Sevindik, Tugba Ongun
A1  - Tunca, Hatice
A1  - OEnem, Burcin
A1  - Aleksovski, Boris
A1  - Krstic, Svetislav
A1  - Vucelic, Itana Bokan
A1  - Nawrocka, Lidia
A1  - Salmi, Pauliina
A1  - Machado-Vieira, Danielle
A1  - de Oliveira, Alinne Gurjao
A1  - Delgado-Martin, Jordi
A1  - Garcia, David
A1  - Cereijo, Jose Luis
A1  - Goma, Joan
A1  - Trapote, Mari Carmen
A1  - Vegas-Vilarrubia, Teresa
A1  - Obrador, Biel
A1  - Grabowska, Magdalena
A1  - Karpowicz, Maciej
A1  - Chmura, Damian
A1  - Ubeda, Barbara
A1  - Angel Galvez, Jose
A1  - Ozen, Arda
A1  - Christoffersen, Kirsten Seestern
A1  - Warming, Trine Perlt
A1  - Kobos, Justyna
A1  - Mazur-Marzec, Hanna
A1  - Perez-Martinez, Carmen
A1  - Ramos-Rodriguez, Eloisa
A1  - Arvola, Lauri
A1  - Alcaraz-Parraga, Pablo
A1  - Toporowska, Magdalena
A1  - Pawlik-Skowronska, Barbara
A1  - Niedzwiecki, Michal
A1  - Peczula, Wojciech
A1  - Leira, Manel
A1  - Hernandez, Armand
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  - Miguel Soria, Juan
A1  - Dunalska, Julita
A1  - Sienska, Justyna
A1  - Szymanski, Daniel
A1  - Kruk, Marek
A1  - Kostrzewska-Szlakowska, Iwona
A1  - Jasser, Iwona
A1  - Zutinic, Petar
A1  - Udovic, Marija Gligora
A1  - Plenkovic-Moraj, Andelka
A1  - Frak, Magdalena
A1  - Bankowska-Sobczak, Agnieszka
A1  - Wasilewicz, Michal
A1  - Ozkan, Korhan
A1  - Maliaka, Valentini
A1  - Kangro, Kersti
A1  - Grossart, Hans-Peter
A1  - Paerl, Hans W.
A1  - Carey, Cayelan C.
A1  - Ibelings, Bas W.
T1  - Temperature effects explain continental scale distribution of cyanobacterial toxins
JF  - Toxins
N2  - Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.
KW  - microcystin
KW  - anatoxin
KW  - cylindrospermopsin
KW  - temperature
KW  - direct effects
KW  - indirect effects
KW  - spatial distribution
KW  - European Multi Lake Survey
Y1  - 2018
U6  - https://doi.org/10.3390/toxins10040156
SN  - 2072-6651
VL  - 10
IS  - 4
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Hartman, Jan F.
A1  - Gentz, Torben
A1  - Schiller, Amanda
A1  - Greule, Markus
A1  - Grossart, Hans-Peter
A1  - Ionescu, Danny
A1  - Keppler, Frank
A1  - Martinez-Cruz, Karla
A1  - Sepulveda-Jauregui, Armando
A1  - Isenbeck-Schroeter, Margot
T1  - A f ast and sensitive method for the continuous in situ determination of dissolved methane and its delta C-13-isotope ratio in surface waters
JF  - Limnology and Oceanography-methods
N2  - A fast and sensitive method for the continuous determination of methane (CH4) and its stable carbon isotopic values (delta C-13-CH4) in surface waters was developed by applying a vacuum to a gas/liquid exchange membrane and measuring the extracted gases by a portable cavity ring-down spectroscopy analyser (M-CRDS). The M-CRDS was calibrated and characterized for CH4 concentration and delta C-13-CH4 with synthetic water standards. The detection limit of the M-CRDS for the simultaneous determination of CH4 and delta C-13-CH4 is 3.6 nmol L-1 CH4. A measurement precision of CH4 concentrations and delta C-13-CH4 in the range of 1.1%, respectively, 1.7 parts per thousand (1 sigma) and accuracy (1.3%, respectively, 0.8 parts per thousand [1 sigma]) was achieved for single measurements and averaging times of 10 min. The response time tau of 57 +/- 5 s allow determination of delta C-13-CH4 values more than twice as fast than other methods. The demonstrated M-CRDS method was applied and tested for Lake Stechlin (Germany) and compared with the headspace-gas chromatography and fast membrane CH4 concentration methods. Maximum CH4 concentrations (577 nmol L-1) and lightest delta C-13-CH4 (-35.2 parts per thousand) were found around the thermocline in depth profile measurements. The M-CRDS-method was in good agreement with other methods. Temporal variations in CH4 concentration and delta C-13-CH4 obtained in 24 h measurements indicate either local methane production/oxidation or physical variations in the thermocline. Therefore, these results illustrate the need of fast and sensitive analyses to achieve a better understanding of different mechanisms and pathways of CH4 formation in aquatic environments.
Y1  - 2018
U6  - https://doi.org/10.1002/lom3.10244
SN  - 1541-5856
VL  - 16
IS  - 5
SP  - 273
EP  - 285
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Garcia, Sarahi L.
A1  - Buck, Moritz
A1  - Hamilton, Joshua J.
A1  - Wurzbacher, Christian
A1  - Grossart, Hans-Peter
A1  - McMahon, Katherine D.
A1  - Eiler, Alexander
T1  - Model communities hint at promiscuous metabolic linkages between ubiquitous free-living freshwater bacteria
JF  - mSphere
N2  - Genome streamlining is frequently observed in free-living aquatic microorganisms and results in physiological dependencies between microorganisms. However, we know little about the specificity of these microbial associations. In order to examine the specificity and extent of these associations, we established mixed cultures from three different freshwater environments and analyzed the cooccurrence of organisms using a metagenomic time series. Free-living microorganisms with streamlined genomes lacking multiple biosynthetic pathways showed no clear recurring pattern in their interaction partners. Free-living freshwater bacteria form promiscuous cooperative associations. This notion contrasts with the well-documented high specificities of interaction partners in host-associated bacteria. Considering all data together, we suggest that highly abundant free-living bacterial lineages are functionally versatile in their interactions despite their distinct streamlining tendencies at the single-cell level. This metabolic versatility facilitates interactions with a variable set of community members.
KW  - community
KW  - interactions
KW  - metagenomics
KW  - microbial ecology
KW  - mixed cultures
KW  - promiscuous
Y1  - 2018
U6  - https://doi.org/10.1128/mSphere.00202-18
SN  - 2379-5042
VL  - 3
IS  - 3
PB  - American Society for Microbiology
CY  - Washington
ER  - 
TY  - JOUR
A1  - Arias-Andres, Maria
A1  - Kluemper, Uli
A1  - Rojas-Jimenez, Keilor
A1  - Grossart, Hans-Peter
T1  - Microplastic pollution increases gene exchange in aquatic ecosystems
JF  - Environmental pollution
N2  - Pollution by microplastics in aquatic ecosystems is accumulating at an unprecedented scale, emerging as a new surface for biofilm formation and gene exchange. In this study, we determined the permissiveness of aquatic bacteria towards a model antibiotic resistance plasmid, comparing communities that form biofilms on microplastics vs. those that are free-living. We used an exogenous and red-fluorescent E. coli donor strain to introduce the green-fluorescent broad-host-range plasmid pKJKS which encodes for trimethoprim resistance. We demonstrate an increased frequency of plasmid transfer in bacteria associated with microplastics compared to bacteria that are free-living or in natural aggregates. Moreover, comparison of communities grown on polycarbonate filters showed that increased gene exchange occurs in a broad range of phylogenetically-diverse bacteria. Our results indicate horizontal gene transfer in this habitat could distinctly affect the ecology of aquatic microbial communities on a global scale. The spread of antibiotic resistance through microplastics could also have profound consequences for the evolution of aquatic bacteria and poses a neglected hazard for human health.
KW  - Microplastics
KW  - Aquatic ecosystems
KW  - Biofilm
KW  - Horizontal gene transfer
KW  - Antibiotic resistance
Y1  - 2018
U6  - https://doi.org/10.1016/j.envpol.2018.02.058
SN  - 0269-7491
SN  - 1873-6424
VL  - 237
SP  - 253
EP  - 261
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Fabian, Jenny
A1  - Zlatanovic, Sanja
A1  - Mutz, Michael
A1  - Grossart, Hans-Peter
A1  - van Geldern, Robert
A1  - Ulrich, Andreas
A1  - Gleixner, Gerd
A1  - Premke, Katrin
T1  - Environmental control on microbial turnover of leaf carbon in streams
BT  - Ecological function of phototrophic-heterotrophic interactions
JF  - Frontiers in microbiology
N2  - In aquatic ecosystems, light availability can significantly influence microbial turnover of terrestrial organic matter through associated metabolic interactions between phototrophic and heterotrophic communities. However, particularly in streams, microbial functions vary significantly with the structure of the streambed, that is the distribution and spatial arrangement of sediment grains in the streambed. It is therefore essential to elucidate how environmental factors synergistically define the microbial turnover of terrestrial organic matter in order to better understand the ecological role of photoheterotrophic interactions in stream ecosystem processes. In outdoor experimental streams, we examined how the structure of streambeds modifies the influence of light availability on microbial turnover of leaf carbon (C). Furthermore, we investigated whether the studied relationships of microbial leaf C turnover to environmental conditions are affected by flow intermittency commonly occurring in streams. We applied leaves enriched with a C-13-stable isotope tracer and combined quantitative and isotope analyses. We thereby elucidated whether treatment induced changes in C turnover were associated with altered use of leaf C within the microbial food web. Moreover, isotope analyses were combined with measurements of microbial community composition to determine whether changes in community function were associated with a change in community composition. In this study, we present evidence, that environmental factors interactively determine how phototrophs and heterotrophs contribute to leaf C turnover. Light availability promoted the utilization of leaf C within the microbial food web, which was likely associated with a promoted availability of highly bioavailable metabolites of phototrophic origin. However, our results additionally confirm that the structure of the streambed modifies light-related changes in microbial C turnover. From our observations, we conclude that the streambed structure influences the strength of photo-heterotrophic interactions by defining the spatial availability of algal metabolites in the streambed and the composition of microbial communities. Collectively, our multifactorial approach provides valuable insights into environmental controls on the functioning of stream ecosystems.
KW  - algae
KW  - bacteria
KW  - microbial interactions
KW  - C-13 stable isotopes
KW  - PLFA
KW  - terrestrial carbon
KW  - streambed structure
KW  - light
Y1  - 2018
U6  - https://doi.org/10.3389/fmicb.2018.01044
SN  - 1664-302X
VL  - 9
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  -