@article{MehnerAttermeyerBraunsetal.2016,
  author    = {Mehner, T. and Attermeyer, Katrin and Brauns, Mario and Brothers, Soren M. and Diekmann, J. and Gaedke, Ursula and Grossart, Hans-Peter and Koehler, J. and Lischke, Betty and Meyer, N. and Scharnweber, Inga Kristin and Syvaranta, J. and Vanni, M. J. and Hilt, S.},
  title     = {Weak Response of Animal Allochthony and Production to Enhanced Supply of Terrestrial Leaf Litter in Nutrient-Rich Lakes},
  series = {Ecosystems},
  volume    = {19},
  journal   = {Ecosystems},
  publisher = {Springer},
  address   = {New York},
  issn      = {1432-9840},
  doi       = {10.1007/s10021-015-9933-2},
  pages     = {311 -- 325},
  year      = {2016},
  abstract  = {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.},
  language  = {en}
}
@article{IzhitskiyZavialovSapozhnikovetal.2016,
  author    = {Izhitskiy, A. S. and Zavialov, P. O. and Sapozhnikov, P. V. and Kirillin, G. B. and Grossart, Hans-Peter and Kalinina, O. Y. and Zalota, A. K. and Goncharenko, I. V. and Kurbaniyazov, A. K.},
  title     = {Present state of the Aral Sea: diverging physical and biological characteristics of the residual basins},
  series = {Scientific reports},
  volume    = {6},
  journal   = {Scientific reports},
  publisher = {Nature Publ. Group},
  address   = {London},
  issn      = {2045-2322},
  doi       = {10.1038/srep23906},
  pages     = {1435 -- 1442},
  year      = {2016},
  abstract  = {Latest data on the hydrophysical and biological state of the residual basins of the Aral Sea are presented and compared. Direct, quasi-simultaneous observations were carried out in the central part of the Western Large Aral Sea, the northern extremity of the Large Aral known as Chernyshev Bay, Lake Tshchebas, and the Small Aral Sea in October 2014. The Large Aral Sea and Lake Tshchebas transformed into hyperhaline water bodies with highly special taxocene structure. The Small Aral Sea was a relatively diverse brackish ecosystem, which was rather similar to the pre-desiccation environment. The Small Aral Sea and Lake Tshchebas exhibited a fully-mixed vertical structure, whereas the Western Large Aral Sea was strongly stratified. Our data show that during desiccation, different parts of the Aral Sea experienced different environmental conditions, resulting in qualitative and quantitative differences in the physical and biological regimes among the different residual basins.},
  language  = {en}
}
@article{AdelElbeheryAzizetal.2016,
  author    = {Adel, Mustafa and Elbehery, Ali H. A. and Aziz, Sherry K. and Aziz, Ramy K. and Grossart, Hans-Peter and Siam, Rania},
  title     = {Viruses-to-mobile genetic elements skew in the deep Atlantis II brine pool sediments},
  series = {Scientific reports},
  volume    = {6},
  journal   = {Scientific reports},
  publisher = {Nature Publ. Group},
  address   = {London},
  issn      = {2045-2322},
  doi       = {10.1038/srep32704},
  pages     = {8882 -- 8888},
  year      = {2016},
  abstract  = {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.},
  language  = {en}
}
@misc{MarceGeorgeBuscarinuetal.2016,
  author    = {Marce, Rafael and George, Glen and Buscarinu, Paola and Deidda, Melania and Dunalska, Julita and de Eyto, Elvira and Flaim, Giovanna and Grossart, Hans-Peter and Istvanovics, Vera and Lenhardt, Mirjana and Moreno-Ostos, Enrique and Obrador, Biel and Ostrovsky, Ilia and Pierson, Donald C. and Potuzak, Jan and Poikane, Sandra and Rinke, Karsten and Rodriguez-Mozaz, Sara and Staehr, Peter A. and Sumberova, Katerina and Waajen, Guido and Weyhenmeyer, Gesa A. and Weathers, Kathleen C. and Zion, Mark and Ibelings, Bas W. and Jennings, Eleanor},
  title     = {Automatic High Frequency Monitoring for Improved Lake and Reservoir Management},
  series = {Frontiers in plant science},
  volume    = {50},
  journal   = {Frontiers in plant science},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0013-936X},
  doi       = {10.1021/acs.est.6b01604},
  pages     = {10780 -- 10794},
  year      = {2016},
  abstract  = {Recent technological developments have increased the number of variables being monitored in lakes and reservoirs using automatic high frequency monitoring (AHFM). However, design of AHFM systems and posterior data handling and interpretation are currently being developed on a site-by-site and issue-by-issue basis with minimal standardization of protocols or knowledge sharing. As a result, many deployments become short-lived or underutilized, and many new scientific developments that are potentially useful for water management and environmental legislation remain underexplored. This Critical Review bridges scientific uses of AHFM with their applications by providing an overview of the current AHFM capabilities, together with examples of successful applications. We review the use of AHFM for maximizing the provision of ecosystem services supplied, by lakes and reservoirs (consumptive and non consumptive uses, food production, and recreation), and for reporting lake status in the EU Water Framework Directive. We also highlight critical issues to enhance the application of AHFM, and suggest the establishment of appropriate networks to facilitate knowledge sharing and technological transfer between potential users. Finally, we give advice on how modern sensor technology can successfully be applied on a larger scale to the management of lakes and reservoirs and maximize the ecosystem services they provide.},
  language  = {en}
}
@article{SpillingSchulzPauletal.2016,
  author    = {Spilling, Kristian and Schulz, Kai G. and Paul, Allanah J. and Boxhammer, Tim and Achterberg, Eric Pieter and Hornick, Thomas and Lischka, Silke and Stuhr, Annegret and Bermudez, Rafael and Czerny, Jan and Crawfurd, Kate and Brussaard, Corina P. D. and Grossart, Hans-Peter and Riebesell, Ulf},
  title     = {Effects of ocean acidification on pelagic carbon fluxes in a mesocosm experiment},
  series = {Biogeosciences},
  volume    = {13},
  journal   = {Biogeosciences},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {1726-4170},
  doi       = {10.5194/bg-13-6081-2016},
  pages     = {6081 -- 6093},
  year      = {2016},
  abstract  = {About a quarter of anthropogenic CO2 emissions are currently taken up by the oceans, decreasing seawater pH. We performed a mesocosm experiment in the Baltic Sea in order to investigate the consequences of increasing CO2 levels on pelagic carbon fluxes. A gradient of different CO2 scenarios, ranging from ambient (similar to 370 mu atm) to high (similar to 1200 mu atm), were set up in mesocosm bags (similar to 55m(3)). We determined standing stocks and temporal changes of total particulate carbon (TPC), dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and particulate organic carbon (POC) of specific plankton groups. We also measured carbon flux via CO2 exchange with the atmosphere and sedimentation (export), and biological rate measurements of primary production, bacterial production, and total respiration. The experiment lasted for 44 days and was divided into three different phases (I: t0-t16; II: t17-t30; III: t31-t43). Pools of TPC, DOC, and DIC were approximately 420, 7200, and 25 200 mmol Cm-2 at the start of the experiment, and the initial CO2 additions increased the DIC pool by similar to 7\% in the highest CO2 treatment. Overall, there was a decrease in TPC and increase of DOC over the course of the experiment. The decrease in TPC was lower, and increase in DOC higher, in treatments with added CO2. During phase I the estimated gross primary production (GPP) was similar to 100 mmol C m(-2) day(-1), from which 75-95\% was respired, similar to 1\% ended up in the TPC (including export), and 5-25\% was added to the DOC pool. During phase II, the respiration loss increased to similar to 100\% of GPP at the ambient CO2 concentration, whereas respiration was lower (85-95\% of GPP) in the highest CO2 treatment. Bacterial production was similar to 30\% lower, on average, at the highest CO2 concentration than in the controls during phases II and III. This resulted in a higher accumulation of DOC and lower reduction in the TPC pool in the elevated CO2 treatments at the end of phase II extending throughout phase III. The "extra" organic carbon at high CO2 remained fixed in an increasing biomass of small-sized plankton and in the DOC pool, and did not transfer into large, sinking aggregates. Our results revealed a clear effect of increasing CO2 on the carbon budget and mineralization, in particular under nutrient limited conditions. Lower carbon loss processes (respiration and bacterial remineralization) at elevated CO2 levels resulted in higher TPC and DOC pools than ambient CO2 concentration. These results highlight the importance of addressing not only net changes in carbon standing stocks but also carbon fluxes and budgets to better disentangle the effects of ocean acidification.},
  language  = {en}
}
@article{CepakovaHrouzekZiskovaetal.2016,
  author    = {Cepakova, Zuzana and Hrouzek, Pavel and Ziskova, Eva and Nuyanzina-Boldareva, Ekaterina and Sorf, Michal and Kozlikova-Zapomelova, Eliska and Salka, Ivette and Grossart, Hans-Peter and Koblizek, Michal},
  title     = {High turnover rates of aerobic anoxygenic phototrophs in European freshwater lakes},
  series = {Environmental microbiology},
  volume    = {18},
  journal   = {Environmental microbiology},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {1462-2912},
  doi       = {10.1111/1462-2920.13475},
  pages     = {5063 -- 5071},
  year      = {2016},
  abstract  = {Aerobic Anoxygenic Phototrophic (AAP) bacteria are bacteriochlorophyll (BChl) a -containing organisms which use light energy to supplement their predominantly heterotrophic metabolism. Here, we investigated mortality and growth rates of AAP bacteria in three different freshwater lakes in Central Europe: the mountain lake Plesne, the oligo-mesotrophic Lake Stechlin and the forest pond Huntov. The mortality of AAP bacteria was estimated from diel changes of BChl a fluorescence. Net and gross growth rates were calculated from the increases in AAP cell numbers. The gross growth rates of AAP bacteria ranged from 0.38 to 5.6 d(-1), with the highest values observed during summer months. Simultaneously, the rapidly growing AAP cells have to cope with an intense grazing pressure by both zooplankton and protists. The presented results document that during the day, gross growth usually surpased mortality. Our results indicate that AAP bacteria utilize light energy under natural conditions to maintain rapid growth rates, which are balanced by a generally intense grazing pressure.},
  language  = {en}
}
@misc{SpillingSchulzPauletal.2016,
  author    = {Spilling, Kristian and Schulz, Kai Georg and Paul, Allanah J. and Boxhammer, Tim and Achterberg, Eric Pieter and Hornick, Thomas and Lischka, Silke and Stuhr, Annegret and Berm{\´u}dez, Rafael and Czerny, Jan and Crawfurd, Kate and Brussaard, Corina P. D. and Grossart, Hans-Peter and Riebesell, Ulf},
  title     = {Effects of ocean acidification on pelagic carbon fluxes in a mesocosm experiment},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {544},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-41183},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-411835},
  pages     = {13},
  year      = {2016},
  abstract  = {About a quarter of anthropogenic CO2 emissions are currently taken up by the oceans, decreasing seawater pH. We performed a mesocosm experiment in the Baltic Sea in order to investigate the consequences of increasing CO2 levels on pelagic carbon fluxes. A gradient of different CO2 scenarios, ranging from ambient (similar to 370 mu atm) to high (similar to 1200 mu atm), were set up in mesocosm bags (similar to 55m(3)). We determined standing stocks and temporal changes of total particulate carbon (TPC), dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and particulate organic carbon (POC) of specific plankton groups. We also measured carbon flux via CO2 exchange with the atmosphere and sedimentation (export), and biological rate measurements of primary production, bacterial production, and total respiration. The experiment lasted for 44 days and was divided into three different phases (I: t0-t16; II: t17-t30; III: t31-t43). Pools of TPC, DOC, and DIC were approximately 420, 7200, and 25 200 mmol Cm-2 at the start of the experiment, and the initial CO2 additions increased the DIC pool by similar to 7\% in the highest CO2 treatment. Overall, there was a decrease in TPC and increase of DOC over the course of the experiment. The decrease in TPC was lower, and increase in DOC higher, in treatments with added CO2. During phase I the estimated gross primary production (GPP) was similar to 100 mmol C m(-2) day(-1), from which 75-95\% was respired, similar to 1\% ended up in the TPC (including export), and 5-25\% was added to the DOC pool. During phase II, the respiration loss increased to similar to 100\% of GPP at the ambient CO2 concentration, whereas respiration was lower (85-95\% of GPP) in the highest CO2 treatment. Bacterial production was similar to 30\% lower, on average, at the highest CO2 concentration than in the controls during phases II and III. This resulted in a higher accumulation of DOC and lower reduction in the TPC pool in the elevated CO2 treatments at the end of phase II extending throughout phase III. The "extra" organic carbon at high CO2 remained fixed in an increasing biomass of small-sized plankton and in the DOC pool, and did not transfer into large, sinking aggregates. Our results revealed a clear effect of increasing CO2 on the carbon budget and mineralization, in particular under nutrient limited conditions. Lower carbon loss processes (respiration and bacterial remineralization) at elevated CO2 levels resulted in higher TPC and DOC pools than ambient CO2 concentration. These results highlight the importance of addressing not only net changes in carbon standing stocks but also carbon fluxes and budgets to better disentangle the effects of ocean acidification.},
  language  = {en}
}
@misc{NauschBachCzernyetal.2016,
  author    = {Nausch, Monika and Bach, Lennart Thomas and Czerny, Jan and Goldstein, Josephine and Grossart, Hans-Peter and Hellemann, Dana and Hornick, Thomas and Achterberg, Eric Pieter and Schulz, Kai Georg and Riebesell, Ulf},
  title     = {Effects of CO 2 perturbation on phosphorus pool sizes and uptake in a mesocosm experiment during a low productive summer season in the northern Baltic Sea},
  series = {Biogeosciences},
  journal   = {Biogeosciences},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-410274},
  pages     = {16},
  year      = {2016},
  abstract  = {Studies investigating the effect of increasing CO2 levels on the phosphorus cycle in natural waters are lacking although phosphorus often controls phytoplankton development in many aquatic systems. The aim of our study was to analyse effects of elevated CO2 levels on phosphorus pool sizes and uptake. The phosphorus dynamic was followed in a CO2-manipulation mesocosm experiment in the Storfjarden (western Gulf of Finland, Baltic Sea) in summer 2012 and was also studied in the surrounding fjord water. In all mesocosms as well as in surface waters of Storfjarden, dissolved organic phosphorus (DOP) concentrations of 0.26aEuro-+/- aEuro-0.03 and 0.23aEuro-+/- aEuro-0.04aEuro-A mu molaEuro-L-1, respectively, formed the main fraction of the total P-pool (TP), whereas phosphate (PO4) constituted the lowest fraction with mean concentration of 0.15aEuro-A +/- aEuro-0.02 in the mesocosms and 0.17aEuro-A +/- aEuro-0.07aEuro-A mu molaEuro-L-1 in the fjord. Transformation of PO4 into DOP appeared to be the main pathway of PO4 turnover. About 82aEuro-\% of PO4 was converted into DOP whereby only 18aEuro-\% of PO4 was transformed into particulate phosphorus (PP). PO4 uptake rates measured in the mesocosms ranged between 0.6 and 3.9aEuro-nmolaEuro-L(-1)aEuro-h(-1). About 86aEuro-\% of them was realized by the size fraction < aEuro-3aEuro-A mu m. Adenosine triphosphate (ATP) uptake revealed that additional P was supplied from organic compounds accounting for 25-27aEuro-\% of P provided by PO4 only. CO2 additions did not cause significant changes in phosphorus (P) pool sizes, DOP composition, and uptake of PO4 and ATP when the whole study period was taken into account. However, significant short-term effects were observed for PO4 and PP pool sizes in CO2 treatments > aEuro-1000aEuro-A mu atm during periods when phytoplankton biomass increased. In addition, we found significant relationships (e.g., between PP and Chl a) in the untreated mesocosms which were not observed under high fCO(2) conditions. Consequently, it can be hypothesized that the relationship between PP formation and phytoplankton growth changed with CO2 elevation. It can be deduced from the results, that visible effects of CO2 on P pools are coupled to phytoplankton growth when the transformation of PO4 into POP was stimulated. The transformation of PO4 into DOP on the other hand does not seem to be affected. Additionally, there were some indications that cellular mechanisms of P regulation might be modified under CO2 elevation changing the relationship between cellular constituents.},
  language  = {en}
}