TY  - JOUR
A1  - Tang, Kam W.
A1  - Gladyshev, Michail I.
A1  - Dubovskaya, Olgo P.
A1  - Kirillin, Georgiy
A1  - Grossart, Hans-Peter
T1  - Zooplankton carcasses and non-predatory mortality in freshwater and inland sea environments
JF  - Journal of plankton research
N2  - Zooplankton carcasses are ubiquitous in marine and freshwater systems, implicating the importance of non-predatory mortality, but both are often overlooked in ecological studies compared with predatory mortality. The development of several microscopic methods allows the distinction between live and dead zooplankton in field samples, and the reported percentages of dead zooplankton average 11.6 (minimum) to 59.8 (maximum) in marine environments, and 7.4 (minimum) to 47.6 (maximum) in fresh and inland waters. Common causes of non-predatory mortality among zooplankton include senescence, temperature change, physical and chemical stresses, parasitism and food-related factors. Carcasses resulting from non-predatory mortality may undergo decomposition leading to an increase in microbial production and a shift in microbial composition in the water column. Alternatively, sinking carcasses may contribute significantly to vertical carbon flux especially outside the phytoplankton growth seasons, and become a food source for the benthos. Global climate change is already altering freshwater ecosystems on multiple levels, and likely will have significant positive or negative effects on zooplankton non-predatory mortality. Better spatial and temporal studies of zooplankton carcasses and non-predatory mortality rates will improve our understanding of this important but under-appreciated topic.
KW  - carbon flux
KW  - inland waters
KW  - lakes
KW  - live
KW  - dead sorting
KW  - non-predatory mortality
KW  - zooplankton carcasses
Y1  - 2014
U6  - https://doi.org/10.1093/plankt/fbu014
SN  - 0142-7873
SN  - 1464-3774
VL  - 36
IS  - 3
SP  - 597
EP  - 612
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Bjorneras, C.
A1  - Weyhenmeyer, G. A.
A1  - Evans, C. D.
A1  - Gessner, M. O.
A1  - Großart, Hans-Peter
A1  - Kangur, K.
A1  - Kokorite, I.
A1  - Kortelainen, P.
A1  - Laudon, H.
A1  - Lehtoranta, J.
A1  - Lottig, N.
A1  - Monteith, D. T.
A1  - Noges, P.
A1  - Noges, T.
A1  - Oulehle, F.
A1  - Riise, G.
A1  - Rusak, J. A.
A1  - Raike, A.
A1  - Sire, J.
A1  - Sterling, S.
A1  - Kritzberg, E. S.
T1  - Widespread Increases in Iron Concentration in European and North American Freshwaters
JF  - Global biogeochemical cycles
N2  - Recent reports of increasing iron (Fe) concentrations in freshwaters are of concern, given the fundamental role of Fe in biogeochemical processes. Still, little is known about the frequency and geographical distribution of Fe trends or about the underlying drivers. We analyzed temporal trends of Fe concentrations across 340 water bodies distributed over 10 countries in northern Europe and North America in order to gain a clearer understanding of where, to what extent, and why Fe concentrations are on the rise. We found that Fe concentrations have significantly increased in 28% of sites, and decreased in 4%, with most positive trends located in northern Europe. Regions with rising Fe concentrations tend to coincide with those with organic carbon (OC) increases. Fe and OC increases may not be directly mechanistically linked, but may nevertheless be responding to common regional-scale drivers such as declining sulfur deposition or hydrological changes. A role of hydrological factors was supported by covarying trends in Fe and dissolved silica, as these elements tend to stem from similar soil depths. A positive relationship between Fe increases and conifer cover suggests that changing land use and expanded forestry could have contributed to enhanced Fe export, although increases were also observed in nonforested areas. We conclude that the phenomenon of increasing Fe concentrations is widespread, especially in northern Europe, with potentially significant implications for wider ecosystem biogeochemistry, and for the current browning of freshwaters.
Y1  - 2017
U6  - https://doi.org/10.1002/2017GB005749
SN  - 0886-6236
SN  - 1944-9224
VL  - 31
SP  - 1488
EP  - 1500
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Mehner, T.
A1  - Attermeyer, Katrin
A1  - Brauns, Mario
A1  - Brothers, Soren M.
A1  - Diekmann, J.
A1  - Gaedke, Ursula
A1  - Grossart, Hans-Peter
A1  - Koehler, J.
A1  - Lischke, Betty
A1  - Meyer, N.
A1  - Scharnweber, Inga Kristin
A1  - Syvaranta, J.
A1  - Vanni, M. J.
A1  - Hilt, S.
T1  - Weak Response of Animal Allochthony and Production to Enhanced Supply of
Terrestrial Leaf Litter in Nutrient-Rich Lakes
JF  - Ecosystems
N2  - Ecosystems are generally linked via fluxes of nutrients and energy across their boundaries. For example, freshwater ecosystems in temperate regions may receive significant inputs of terrestrially derived carbon via autumnal leaf litter. This terrestrial particulate organic carbon (POC) is hypothesized to subsidize animal production in lakes, but direct evidence is still lacking. We divided two small eutrophic lakes each into two sections and added isotopically distinct maize litter to the treatment sections to simulate increased terrestrial POC inputs via leaf litter in autumn. We quantified the reliance of aquatic consumers on terrestrial resources (allochthony) in the year subsequent to POC additions by applying mixing models of stable isotopes. We also estimated lake-wide carbon (C) balances to calculate the C flow to the production of the major aquatic consumer groups: benthic macroinvertebrates, crustacean zooplankton, and fish. The sum of secondary production of crustaceans and benthic macroinvertebrates supported by terrestrial POC was higher in the treatment sections of both lakes. In contrast, total secondary and tertiary production (supported by both autochthonous and allochthonous C) was higher in the reference than in the treatment sections of both lakes. Average aquatic consumer allochthony per lake section was 27-40%, although terrestrial POC contributed less than about 10% to total organic C supply to the lakes. The production of aquatic consumers incorporated less than 5% of the total organic C supply in both lakes, indicating a low ecological efficiency. We suggest that the consumption of terrestrial POC by aquatic consumers facilitates a strong coupling with the terrestrial environment. However, the high autochthonous production and the large pool of autochthonous detritus in these nutrient-rich lakes make terrestrial POC quantitatively unimportant for the C flows within food webs.
KW  - stable isotopes
KW  - terrestrial subsidy
KW  - carbon budget
KW  - ecological efficiency
KW  - benthic food web
KW  - pelagic food web
Y1  - 2016
U6  - https://doi.org/10.1007/s10021-015-9933-2
SN  - 1432-9840
SN  - 1435-0629
VL  - 19
SP  - 311
EP  - 325
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Adel, Mustafa
A1  - Elbehery, Ali H. A.
A1  - Aziz, Sherry K.
A1  - Aziz, Ramy K.
A1  - Grossart, Hans-Peter
A1  - Siam, Rania
T1  - Viruses-to-mobile genetic elements skew in the deep Atlantis II brine pool sediments
JF  - Scientific reports
N2  - The central rift of the Red Sea has 25 brine pools with different physical and geochemical characteristics. Atlantis II (ATIID), Discovery Deeps (DD) and Chain Deep (CD) are characterized by high salinity, temperature and metal content. Several studies reported microbial communities in these brine pools, but few studies addressed the brine pool sediments. Therefore, sediment cores were collected from ATIID, DD, CD brine pools and an adjacent brine-influenced site. Sixteen different lithologic sediment sections were subjected to shotgun DNA pyrosequencing to generate 1.47 billion base pairs (1.47 x 10(9) bp). We generated sediment-specific reads and attempted to annotate all reads. We report the phylogenetic and biochemical uniqueness of the deepest ATIID sulfur-rich brine pool sediments. In contrary to all other sediment sections, bacteria dominate the deepest ATIID sulfur-rich brine pool sediments. This decrease in virus-to-bacteria ratio in selected sections and depth coincided with an overrepresentation of mobile genetic elements. Skewing in the composition of viruses-to-mobile genetic elements may uniquely contribute to the distinct microbial consortium in sediments in proximity to hydrothermally active vents of the Red Sea and possibly in their surroundings, through differential horizontal gene transfer.
Y1  - 2016
U6  - https://doi.org/10.1038/srep32704
SN  - 2045-2322
VL  - 6
SP  - 8882
EP  - 8888
PB  - Nature Publ. Group
CY  - London
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  - Rojas-Jimenez, Keilor
A1  - Fonvielle, Jeremy Andre
A1  - Ma, Hua
A1  - Grossart, Hans-Peter
T1  - Transformation of humic substances by the freshwater Ascomycete Cladosporium sp.
JF  - Waterbird
N2  - The ecological relevance of fungi in freshwater ecosystems is becoming increasingly evident, particularly in processing the extensive amounts of polymeric organic carbon such as cellulose, chitin, and humic substances (HS). We isolated several fungal strains from oligo-mesotrophic Lake Stechlin, Brandenburg, Germany, and analyzed their ability to degrade polymeric-like substrates. Using liquid chromatography-organic carbon detection, we determined the byproducts of HS transformation by the freshwater fungus Cladosporium sp. KR14. We demonstrate the ability of this fungus to degrade and simultaneously synthesize HS, and that transformation processes were intensified when iron, as indicator of the occurrence of Fenton reactions, was present in the medium. Furthermore, we showed that structural complexity of the HS produced changed with the availability of other polymeric substances in the medium. Our study highlights the contribution of freshwater Ascomycetes to the transformation of complex organic compounds. As such, it has important implications for understanding the ecological contribution of fungi to aquatic food webs and related biogeochemical cycles.
Y1  - 2017
U6  - https://doi.org/10.1002/lno.10545
SN  - 1524-4695
SN  - 1938-5390
VL  - 40
SP  - 282
EP  - 288
PB  - Waterbird SOC
CY  - Washington
ER  - 
TY  - JOUR
A1  - Krause, Sascha
A1  - Le Roux, Xavier
A1  - Niklaus, Pascal A.
A1  - Van Bodegom, Peter M.
A1  - Lennon, Jay T.
A1  - Bertilsson, Stefan
A1  - Grossart, Hans-Peter
A1  - Philippot, Laurent
A1  - Bodelier, Paul L. E.
T1  - Trait-based approaches for understanding microbial biodiversity and ecosystem functioning
JF  - Frontiers in microbiology
N2  - In ecology, biodiversity-ecosystem functioning (BEE) research has seen a shift in perspective from taxonomy to function in the last two decades, with successful application of trait-based approaches. This shift offers opportunities for a deeper mechanistic understanding of the role of biodiversity in maintaining multiple ecosystem processes and services. In this paper, we highlight studies that have focused on BEE of microbial communities with an emphasis on integrating trait-based approaches to microbial ecology. In doing so, we explore some of the inherent challenges and opportunities of understanding BEE using microbial systems. For example, microbial biologists characterize communities using gene phylogenies that are often unable to resolve functional traits. Additionally, experimental designs of existing microbial BEE studies are often inadequate to unravel BEE relationships. We argue that combining eco-physiological studies with contemporary molecular tools in a trait-based framework can reinforce our ability to link microbial diversity to ecosystem processes. We conclude that such trait-based approaches are a promising framework to increase the understanding of microbial BEE relationships and thus generating systematic principles in microbial ecology and more generally ecology.
KW  - functional traits
KW  - ecosystem function
KW  - ecological theory
KW  - study designs
KW  - microbial diversity
Y1  - 2014
U6  - https://doi.org/10.3389/fmicb.2014.00251
SN  - 1664-302X
VL  - 5
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Amalfitano, Stefano
A1  - Corno, Gianluca
A1  - Eckert, Ester
A1  - Fazi, Stefano
A1  - Ninio, Shira
A1  - Callieri, Cristiana
A1  - Grossart, Hans-Peter
A1  - Eckert, Werner
T1  - Tracing particulate matter and associated microorganisms in freshwaters
JF  - Hydrobiologia : acta hydrobiologica, hydrographica, limnologica et protistologica
N2  - Sediment resuspension represents a key process in all natural aquatic systems, owing to its role in nutrient cycling and transport of potential contaminants. Although suspended solids are generally accepted as an important quality parameter, current monitoring programs cover quantitative aspects only. Established methodologies do not provide information on origin, fate, and risks associated with uncontrolled inputs of solids in waters. Here we discuss the analytical approaches to assess the occurrence and ecological relevance of resuspended particulate matter in freshwaters, with a focus on the dynamics of associated contaminants and microorganisms. Triggered by the identification of specific physical-chemical traits and community structure of particle-associated microorganisms, recent findings suggest that a quantitative determination of microorganisms can be reasonably used to trace the origin of particulate matter by means of nucleic acid-based assays in different aquatic systems.
KW  - Total suspended solids
KW  - Resuspended particulate
KW  - Turbidity
KW  - Sediment traps
KW  - Particle-associated microorganisms
KW  - Pathogens
Y1  - 2017
U6  - https://doi.org/10.1007/s10750-017-3260-x
SN  - 0018-8158
SN  - 1573-5117
VL  - 800
SP  - 145
EP  - 154
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Leunert, Franziska
A1  - Grossart, Hans-Peter
A1  - Gerhardt, Volkmar
A1  - Eckert, Werner
T1  - Toxicant induced changes on delayed fluorescence decay kinetics of cyanobacteria and green algae a rapid and sensitive biotest
JF  - PLoS one
N2  - Algal tests have developed into routine tools for testing toxicity of pollutants in aquatic environments. Meanwhile, in addition to algal growth rates, an increasing number of fluorescence based methods are used for rapid and sensitive toxicity measures. The present study stresses the suitability of delayed fluorescence (DF) as a promising parameter for biotests. DF is based on the recombination fluorescence at the reaction centre of photosystem II, which is emitted only by photosynthetically active cells. We analyzed the effects of three chemicals (3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), 3,5 Dichlorophenol (3,5 DCP) and copper) on the shape of the DF decay kinetics for potential use in phytoplankton toxicity tests. The short incubation tests were done with four phytoplankton species, with special emphasis on the cyanobacterium Microcystis aeruginosa. All species exhibited a high sensitivity to DCMU, but cyanobacteria were more affected by copper and less by 3,5 DCP than the tested green algae. Analyses of changes in the DF decay curve in response to the added chemicals indicated the feasibility of the DF decay approach as a rapid and sensitive testing tool.
Y1  - 2013
U6  - https://doi.org/10.1371/journal.pone.0063127
SN  - 1932-6203
VL  - 8
IS  - 4
PB  - PLoS
CY  - San Fransisco
ER  - 
TY  - JOUR
A1  - Heger, Tina
A1  - Bernard-Verdier, Maud
A1  - Gessler, Arthur
A1  - Greenwood, Alex D.
A1  - Grossart, Hans-Peter
A1  - Hilker, Monika
A1  - Keinath, Silvia
A1  - Kowarik, Ingo
A1  - Küffer, Christoph
A1  - Marquard, Elisabeth
A1  - Mueller, Johannes
A1  - Niemeier, Stephanie
A1  - Onandia, Gabriela
A1  - Petermann, Jana S.
A1  - Rillig, Matthias C.
A1  - Rodel, Mark-Oliver
A1  - Saul, Wolf-Christian
A1  - Schittko, Conrad
A1  - Tockner, Klement
A1  - Joshi, Jasmin Radha
A1  - Jeschke, Jonathan M.
T1  - Towards an Integrative, Eco-Evolutionary Understanding of Ecological Novelty: Studying and Communicating Interlinked Effects of Global Change
JF  - Bioscience
N2  - Global change has complex eco-evolutionary consequences for organisms and ecosystems, but related concepts (e.g., novel ecosystems) do not cover their full range. Here we propose an umbrella concept of "ecological novelty" comprising (1) a site-specific and (2) an organism-centered, eco-evolutionary perspective. Under this umbrella, complementary options for studying and communicating effects of global change on organisms, ecosystems, and landscapes can be included in a toolbox. This allows researchers to address ecological novelty from different perspectives, e.g., by defining it based on (a) categorical or continuous measures, (b) reference conditions related to sites or organisms, and (c) types of human activities. We suggest striving for a descriptive, non-normative usage of the term "ecological novelty" in science. Normative evaluations and decisions about conservation policies or management are important, but require additional societal processes and engagement with multiple stakeholders.
KW  - Anthropocene
KW  - eco-evolutionary experience
KW  - global change
KW  - novel ecosystems
KW  - shifting baselines
Y1  - 2019
U6  - https://doi.org/10.1093/biosci/biz095
SN  - 0006-3568
SN  - 1525-3244
VL  - 69
IS  - 11
SP  - 888
EP  - 899
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Giling, Darren P.
A1  - Nejstgaard, Jens C.
A1  - Berger, Stella A.
A1  - Grossart, Hans-Peter
A1  - Kirillin, Georgiy
A1  - Penske, Armin
A1  - Lentz, Maren
A1  - Casper, Peter
A1  - Sareyka, Joerg
A1  - Gessner, Mark O.
T1  - Thermocline deepening boosts ecosystem metabolism: evidence from a large-scale lake enclosure experiment simulating a summer storm
JF  - Global change biology
N2  - Extreme weather events can pervasively influence ecosystems. Observations in lakes indicate that severe storms in particular can have pronounced ecosystem-scale consequences, but the underlying mechanisms have not been rigorously assessed in experiments. One major effect of storms on lakes is the redistribution of mineral resources and plankton communities as a result of abrupt thermocline deepening. We aimed at elucidating the importance of this effect by mimicking in replicated large enclosures (each 9 m in diameter, ca. 20 m deep, ca. 1300 m 3 in volume) a mixing event caused by a severe natural storm that was previously observed in a deep clear-water lake. Metabolic rates were derived from diel changes in vertical profiles of dissolved oxygen concentrations using a Bayesian modelling approach, based on high-frequency measurements. Experimental thermocline deepening stimulated daily gross primary production (GPP) in surface waters by an average of 63% for > 4 weeks even though thermal stratification re-established within 5 days. Ecosystem respiration (ER) was tightly coupled to GPP, exceeding that in control enclosures by 53% over the same period. As GPP responded more strongly than ER, net ecosystem productivity (NEP) of the entire water column was also increased. These protracted increases in ecosystem metabolism and autotrophy were driven by a proliferation of inedible filamentous cyanobacteria released from light and nutrient limitation after they were entrained from below the thermocline into the surface water. Thus, thermocline deepening by a single severe storm can induce prolonged responses of lake ecosystem metabolism independent of other storm-induced effects, such as inputs of terrestrial materials by increased catchment run-off. This highlights that future shifts in frequency, severity or timing of storms are an important component of climate change, whose impacts on lake thermal structure will superimpose upon climate trends to influence algal dynamics and organic matter cycling in clear-water lakes. Keywords: climate variability, ecosystem productivity, extreme events, gross primary production, mesocosm, respiration stratified lakes
KW  - climate variability
KW  - ecosystem productivity
KW  - extreme events
KW  - gross primary production
KW  - mesocosm
KW  - respiration stratified lakes
Y1  - 2017
U6  - https://doi.org/10.1111/gcb.13512
SN  - 1354-1013
SN  - 1365-2486
VL  - 23
SP  - 1448
EP  - 1462
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Block, Benjamin D.
A1  - Denfeld, Blaize A.
A1  - Stockwell, Jason D.
A1  - Flaim, Giovanna
A1  - Grossart, Hans-Peter
A1  - Knoll, Lesley B.
A1  - Maier, Dominique B.
A1  - North, Rebecca L.
A1  - Rautio, Milla
A1  - Rusak, James A.
A1  - Sadro, Steve
A1  - Weyhenmeyer, Gesa A.
A1  - Bramburger, Andrew J.
A1  - Branstrator, Donn K.
A1  - Salonen, Kalevi
A1  - Hampton, Stephanie E.
T1  - The unique methodological challenges of winter limnology
JF  - Limnology and Oceanography: Methods
N2  - Winter is an important season for many limnological processes, which can range from biogeochemical transformations to ecological interactions. Interest in the structure and function of lake ecosystems under ice is on the rise. Although limnologists working at polar latitudes have a long history of winter work, the required knowledge to successfully sample under winter conditions is not widely available and relatively few limnologists receive formal training. In particular, the deployment and operation of equipment in below 0 degrees C temperatures pose considerable logistical and methodological challenges, as do the safety risks of sampling during the ice-covered period. Here, we consolidate information on winter lake sampling and describe effective methods to measure physical, chemical, and biological variables in and under ice. We describe variation in snow and ice conditions and discuss implications for sampling logistics and safety. We outline commonly encountered methodological challenges and make recommendations for best practices to maximize safety and efficiency when sampling through ice or deploying instruments in ice-covered lakes. Application of such practices over a broad range of ice-covered lakes will contribute to a better understanding of the factors that regulate lakes during winter and how winter conditions affect the subsequent ice-free period.
Y1  - 2018
U6  - https://doi.org/10.1002/lom3.10295
SN  - 1541-5856
VL  - 17
IS  - 1
SP  - 42
EP  - 57
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Bertilsson, Stefan
A1  - Burgin, Amy
A1  - Carey, Cayelan C.
A1  - Fey, Samuel B.
A1  - Grossart, Hans-Peter
A1  - Grubisic, Lorena M.
A1  - Jones, Ian D.
A1  - Kirillin, Georgiy
A1  - Lennon, Jay T.
A1  - Shade, Ashley
A1  - Smyth, Robyn L.
T1  - The under-ice microbiome of seasonally frozen lakes
JF  - Limnology and oceanography
N2  - Compared to the well-studied open water of the "growing" season, under-ice conditions in lakes are characterized by low and rather constant temperature, slow water movements, limited light availability, and reduced exchange with the surrounding landscape. These conditions interact with ice-cover duration to shape microbial processes in temperate lakes and ultimately influence the phenology of community and ecosystem processes. We review the current knowledge on microorganisms in seasonally frozen lakes. Specifically, we highlight how under-ice conditions alter lake physics and the ways that this can affect the distribution and metabolism of auto-and heterotrophic microorganisms. We identify functional traits that we hypothesize are important for understanding under-ice dynamics and discuss how these traits influence species interactions. As ice coverage duration has already been seen to reduce as air temperatures have warmed, the dynamics of the under-ice microbiome are important for understanding and predicting the dynamics and functioning of seasonally frozen lakes in the near future.
Y1  - 2013
U6  - https://doi.org/10.4319/lo.2013.58.6.1998
SN  - 0024-3590
SN  - 1939-5590
VL  - 58
IS  - 6
SP  - 1998
EP  - 2012
PB  - Wiley
CY  - Waco
ER  - 
TY  - JOUR
A1  - Brentrup, Jennifer A.
A1  - Williamson, Craig E.
A1  - Colom-Montero, William
A1  - Eckert, Werner
A1  - de Eyto, Elvira
A1  - Großart, Hans-Peter
A1  - Huot, Yannick
A1  - Isles, Peter D. F.
A1  - Knoll, Lesley B.
A1  - Leach, Taylor H.
A1  - McBride, Chris G.
A1  - Pierson, Don
A1  - Pomati, Francesco
A1  - Read, Jordan S.
A1  - Rose, Kevin C.
A1  - Samal, Nihar R.
A1  - Staehr, Peter A.
A1  - Winslow, Luke A.
T1  - The potential of high-frequency profiling to assess vertical and seasonal patterns of phytoplankton dynamics in lakes: an extension of the Plankton Ecology Group (PEG) model
JF  - Inland waters : journal of the International Society of Limnology
N2  - The use of high-frequency sensors on profiling buoys to investigate physical, chemical, and biological processes in lakes is 
increasing rapidly. Profiling buoys with automated winches and sensors that collect high-frequency chlorophyll fluorescence 
(ChlF) profiles in 11 lakes in the Global Lake Ecological Observatory Network (GLEON) allowed the study of the vertical 
and temporal distribution of ChlF, including the formation of subsurface chlorophyll maxima (SSCM). The effectiveness of 3 
methods for sampling phytoplankton distributions in lakes, including (1) manual profiles, (2) single-depth buoys, and (3) 
profiling buoys were assessed. High-frequency ChlF surface data and profiles were compared to predictions from the 
Plankton Ecology Group (PEG) model. The depth-integrated ChlF dynamics measured by the profiling buoy data revealed a 
greater complexity that neither conventional sampling nor the generalized PEG model captured. Conventional sampling 
techniques would have missed SSCM in 7 of 11 study lakes. Although surface-only ChlF data underestimated average water 
column ChlF, at times by nearly 2-fold in 4 of the lakes, overall there was a remarkable similarity between surface and mean 
water column data. Contrary to the PEG model’s proposed negligible role for physical control of phytoplankton during the 
growing season, thermal structure and light availability were closely associated with ChlF seasonal depth distribution. Thus, 
an extension of the PEG model is proposed, with a new conceptual framework that explicitly includes physical metrics to 
better predict SSCM formation in lakes and highlight when profiling buoys are especially informative.
KW  - chlorophyll fluorescence
KW  - Global Lake Ecological Observatory Network (GLEON)
KW  - high-frequency sensors
KW  - PEG model
KW  - phytoplankton
KW  - profiling buoys
KW  - subsurface chlorophyll maximum
Y1  - 2016
U6  - https://doi.org/10.5268/IW-6.4.890
SN  - 2044-2041
SN  - 2044-205X
VL  - 6
SP  - 565
EP  - 580
PB  - Freshwater Biological Association
CY  - Ambleside
ER  - 
TY  - JOUR
A1  - Sengupta, Saswati
A1  - Chattopadhyay, Madhab K.
A1  - Grossart, Hans-Peter
T1  - The multifaceted roles of antibiotics and antibiotic resistance in nature
JF  - Frontiers in microbiology
N2  - Antibiotics are chemotherapeutic agents, which have been a very powerful tool in the clinical management of bacterial diseases since the 1940s. However, benefits offered by these magic bullets have been substantially lost in subsequent days following the widespread emergence and dissemination of antibiotic-resistant strains. While it is obvious that excessive and imprudent use of antibiotics significantly contributes to the emergence of resistant strains, antibiotic resistance is also observed in natural bacteria of remote places unlikely to be impacted by human intervention. Both antibiotic biosynthetic genes and resistance-conferring genes have been known to evolve billions of years ago, long before clinical use of antibiotics. Hence it appears that antibiotics and antibiotics resistance determinants have some other roles in nature, which often elude our attention because of overemphasis on the therapeutic importance of antibiotics and the crisis imposed by the antibiotic resistance in pathogens. In the natural milieu, antibiotics are often found to be present in sub-inhibitory concentrations acting as signaling molecules supporting the process of quorum sensing and biofilm formation. They also play an important role in the production of virulence factors and influence host-parasite interactions (e.g., phagocytosis, adherence to the target cell, and so on). The evolutionary and ecological aspects of antibiotics and antibiotic resistance in the naturally occurring microbial community are little understood. Therefore, the actual role of antibiotics in nature warrants in-depth investigations. Studies on such an intriguing behavior of the microorganisms promise insight into the intricacies of the microbial physiology and are likely to provide some lead in controlling the emergence and subsequent dissemination of antibiotic resistance. This article highlights some of the recent findings on the role of antibiotics and the genes that confer resistance to antibiotics in nature.
KW  - antibiotics
KW  - sub-inhibitory concentration
KW  - quorum sensing
KW  - virulence
KW  - stress response
KW  - antibiotic resistance
KW  - antibiotic paradox
Y1  - 2013
U6  - https://doi.org/10.3389/fmicb.2013.00047
SN  - 1664-302X
VL  - 4
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Premke, Katrin
A1  - Attermeyer, Katrin
A1  - Augustin, Jürgen
A1  - Cabezas, Alvaro
A1  - Casper, Peter
A1  - Deumlich, Detlef
A1  - Gelbrecht, Jörg
A1  - Gerke, Horst H.
A1  - Gessler, Arthur
A1  - Großart, Hans-Peter
A1  - Hilt, Sabine
A1  - Hupfer, Michael
A1  - Kalettka, Thomas
A1  - Kayler, Zachary
A1  - Lischeid, Gunnar
A1  - Sommer, Michael
A1  - Zak, Dominik
T1  - The importance of landscape diversity for carbon fluxes at the landscape level: small-scale heterogeneity matters
JF  - Wiley Interdisciplinary Reviews : Water
N2  - Landscapes can be viewed as spatially heterogeneous areas encompassing terrestrial and aquatic domains. To date, most landscape carbon (C) fluxes have been estimated by accounting for terrestrial ecosystems, while aquatic ecosystems have been largely neglected. However, a robust assessment of C fluxes on the landscape scale requires the estimation of fluxes within and between both landscape components. Here, we compiled data from the literature on C fluxes across the air–water interface from various landscape components. We simulated C emissions and uptake for five different scenarios which represent a gradient of increasing spatial heterogeneity within a temperate young moraine landscape: (I) a homogeneous landscape with only cropland and large lakes; (II) separation of the terrestrial domain into cropland and forest; (III) further separation into cropland, forest, and grassland; (IV) additional division of the aquatic area into large lakes and peatlands; and (V) further separation of the aquatic area into large lakes, peatlands, running waters, and small water bodies These simulations suggest that C fluxes at the landscape scale might depend on spatial heterogeneity and landscape diversity, among other factors. When we consider spatial heterogeneity and diversity alone, small inland waters appear to play a pivotal and previously underestimated role in landscape greenhouse gas emissions that may be regarded as C hot spots. Approaches focusing on the landscape scale will also enable improved projections of ecosystems’ responses to perturbations, e.g., due to global change and anthropogenic activities, and evaluations of the specific role individual landscape components play in regional C fluxes. WIREs Water 2016, 3:601–617. doi: 10.1002/wat2.1147
Y1  - 2016
U6  - https://doi.org/10.1002/wat2.1147
SN  - 2049-1948
SN  - 2049-1948
VL  - 3
SP  - 601
EP  - 617
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Cook, Katherine V.
A1  - Li, Chuang
A1  - Cai, Haiyuan
A1  - Krumholz, Lee R.
A1  - Hambright, K. David
A1  - Paerl, Hans W.
A1  - Steffen, Morgan M.
A1  - Wilson, Alan E.
A1  - Burford, Michele A.
A1  - Grossart, Hans-Peter
A1  - Hamilton, David P.
A1  - Jiang, Helong
A1  - Sukenik, Assaf
A1  - Latour, Delphine
A1  - Meyer, Elisabeth I.
A1  - Padisak, Judit
A1  - Qin, Boqiang
A1  - Zamor, Richard M.
A1  - Zhu, Guangwei
T1  - The global Microcystis interactome
JF  - Limnology and oceanography
N2  - Bacteria play key roles in the function and diversity of aquatic systems, but aside from study of specific bloom systems, little is known about the diversity or biogeography of bacteria associated with harmful cyanobacterial blooms (cyanoHABs). CyanoHAB species are known to shape bacterial community composition and to rely on functions provided by the associated bacteria, leading to the hypothesized cyanoHAB interactome, a coevolved community of synergistic and interacting bacteria species, each necessary for the success of the others. Here, we surveyed the microbiome associated with Microcystis aeruginosa during blooms in 12 lakes spanning four continents as an initial test of the hypothesized Microcystis interactome. We predicted that microbiome composition and functional potential would be similar across blooms globally. Our results, as revealed by 16S rRNA sequence similarity, indicate that M. aeruginosa is cosmopolitan in lakes across a 280 degrees longitudinal and 90 degrees latitudinal gradient. The microbiome communities were represented by a wide range of operational taxonomic units and relative abundances. Highly abundant taxa were more related and shared across most sites and did not vary with geographic distance, thus, like Microcystis, revealing no evidence for dispersal limitation. High phylogenetic relatedness, both within and across lakes, indicates that microbiome bacteria with similar functional potential were associated with all blooms. While Microcystis and the microbiome bacteria shared many genes, whole-community metagenomic analysis revealed a suite of biochemical pathways that could be considered complementary. Our results demonstrate a high degree of similarity across global Microcystis blooms, thereby providing initial support for the hypothesized Microcystis interactome.
Y1  - 2019
U6  - https://doi.org/10.1002/lno.11361
SN  - 0024-3590
SN  - 1939-5590
VL  - 65
SP  - S194
EP  - S207
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - GEN
A1  - Kettner, Marie Therese
A1  - Oberbeckmann, Sonja
A1  - Labrenz, Matthias
A1  - Grossart, Hans-Peter
T1  - The Eukaryotic Life on Microplastics in Brackish Ecosystems
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - Microplastics (MP) constitute a widespread contaminant all over the globe. Rivers and wastewater treatment plants (WWTP) transport annually several million tons of MP into freshwaters, estuaries and oceans, where they provide increasing artificial surfaces for microbial colonization. As knowledge on MP-attached communities is insufficient for brackish ecosystems, we conducted exposure experiments in the coastal Baltic Sea, an in-flowing river and a WWTP within the drainage basin. While reporting on prokaryotic and fungal communities from the same set-up previously, we focus here on the entire eukaryotic communities. Using high-throughput 18S rRNA gene sequencing, we analyzed the eukaryotes colonizing on two types of MP, polyethylene and polystyrene, and compared them to the ones in the surrounding water and on a natural surface (wood). More than 500 different taxa across almost all kingdoms of the eukaryotic tree of life were identified on MP, dominated by Alveolata, Metazoa, and Chloroplastida. The eukaryotic community composition on MP was significantly distinct from wood and the surrounding water, with overall lower diversity and the potentially harmful dinoflagellate Pfiesteria being enriched on MP. Co-occurrence networks, which include prokaryotic and eukaryotic taxa, hint at possibilities for dynamic microbial interactions on MP. This first report on total eukaryotic communities on MP in brackish environments highlights the complexity of MP-associated biofilms, potentially leading to altered microbial activities and hence changes in ecosystem functions.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 741 
KW  - microeukaryotes
KW  - plastic-associated biofilms
KW  - Baltic Sea
KW  - polyethylene
KW  - polystyrene
KW  - diversity profiles
KW  - network analysis
KW  - next-generation sequencing
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-434996
SN  - 1866-8372
IS  - 741
ER  - 
TY  - JOUR
A1  - Kettner, Marie Therese
A1  - Oberbeckmann, Sonja
A1  - Labrenz, Matthias
A1  - Grossart, Hans-Peter
T1  - The Eukaryotic Life on Microplastics in Brackish Ecosystems
JF  - Frontiers in Microbiology
N2  - Microplastics (MP) constitute a widespread contaminant all over the globe. Rivers and wastewater treatment plants (WWTP) transport annually several million tons of MP into freshwaters, estuaries and oceans, where they provide increasing artificial surfaces for microbial colonization. As knowledge on MP-attached communities is insufficient for brackish ecosystems, we conducted exposure experiments in the coastal Baltic Sea, an in-flowing river and a WWTP within the drainage basin. While reporting on prokaryotic and fungal communities from the same set-up previously, we focus here on the entire eukaryotic communities. Using high-throughput 18S rRNA gene sequencing, we analyzed the eukaryotes colonizing on two types of MP, polyethylene and polystyrene, and compared them to the ones in the surrounding water and on a natural surface (wood). More than 500 different taxa across almost all kingdoms of the eukaryotic tree of life were identified on MP, dominated by Alveolata, Metazoa, and Chloroplastida. The eukaryotic community composition on MP was significantly distinct from wood and the surrounding water, with overall lower diversity and the potentially harmful dinoflagellate Pfiesteria being enriched on MP. Co-occurrence networks, which include prokaryotic and eukaryotic taxa, hint at possibilities for dynamic microbial interactions on MP. This first report on total eukaryotic communities on MP in brackish environments highlights the complexity of MP-associated biofilms, potentially leading to altered microbial activities and hence changes in ecosystem functions.
KW  - microeukaryotes
KW  - plastic-associated biofilms
KW  - Baltic Sea
KW  - polyethylene
KW  - polystyrene
KW  - diversity profiles
KW  - network analysis
KW  - next-generation sequencing
Y1  - 2019
U6  - https://doi.org/10.3389/fmicb.2019.00538
SN  - 1664-302X
VL  - 10
PB  - Frontiers Media
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Masigol, Hossein
A1  - Khodaparast, Seyed Akbar
A1  - Woodhouse, Jason Nicholas
A1  - Rojas Jiménez, Keilor
A1  - Fonvielle, Jeremy Andre
A1  - Rezakhani, Forough
A1  - Mostowfizadeh-Ghalamfarsa, Reza
A1  - Neubauer, Darshan
A1  - Goldhammer, Tobias
A1  - Grossart, Hans-Peter
T1  - The contrasting roles of aquatic fungi and oomycetes in the degradation and transformation of polymeric organic matter
JF  - Limnology and oceanography
N2  - Studies on the ecological role of fungi and, to a lesser extent, oomycetes, are receiving increasing attention, mainly due to their participation in the cycling of organic matter in aquatic ecosystems. To unravel their importance in humification processes, we isolated several strains of fungi and oomycetes from Anzali lagoon, Iran. We then performed taxonomic characterization by morphological and molecular methods, analyzed the ability to degrade several polymeric substrates, performed metabolic fingerprinting with Ecoplates, and determined the degradation of humic substances (HS) using liquid chromatography-organic carbon detection. Our analyses highlighted the capacity of aquatic fungi to better degrade a plethora of organic molecules, including complex polymers. Specifically, we were able to demonstrate not only the utilization of these complex polymers, but also the role of fungi in the production of HS. In contrast, oomycetes, despite some morphological and physiological similarities with aquatic fungi, exhibited a propensity toward opportunism, quickly benefitting from the availability of small organic molecules, while exhibiting sensitivity toward more complex polymers. Despite their contrasting roles, our study highlights the importance of both oomycetes and fungi in aquatic organic matter transformation and cycling with potential implications for the global carbon cycle.
Y1  - 2019
SN  - 0024-3590
SN  - 1939-5590
VL  - 64
IS  - 6
SP  - 2662
EP  - 2678
PB  - Wiley
CY  - Hoboken
ER  -