@article{BrentrupWilliamsonColomMonteroetal.2016,
  author    = {Brentrup, Jennifer A. and Williamson, Craig E. and Colom-Montero, William and Eckert, Werner and de Eyto, Elvira and Großart, Hans-Peter and Huot, Yannick and Isles, Peter D. F. and Knoll, Lesley B. and Leach, Taylor H. and McBride, Chris G. and Pierson, Don and Pomati, Francesco and Read, Jordan S. and Rose, Kevin C. and Samal, Nihar R. and Staehr, Peter A. and Winslow, Luke A.},
  title     = {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},
  series = {Inland waters : journal of the International Society of Limnology},
  volume    = {6},
  journal   = {Inland waters : journal of the International Society of Limnology},
  publisher = {Freshwater Biological Association},
  address   = {Ambleside},
  issn      = {2044-2041},
  doi       = {10.5268/IW-6.4.890},
  pages     = {565 -- 580},
  year      = {2016},
  abstract  = {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.},
  language  = {en}
}
@article{SpijkermanStojkovicHollandetal.2016,
  author    = {Spijkerman, Elly and Stojkovic, Slobodanka and Holland, Daryl and Lachmann, Sabrina C. and Beardall, John},
  title     = {Nutrient induced fluorescence transients (NIFTs) provide a rapid measure of P and C (co-)limitation in a green alga},
  series = {European journal of phycology},
  volume    = {51},
  journal   = {European journal of phycology},
  publisher = {Hindawi},
  address   = {Abingdon},
  issn      = {0967-0262},
  doi       = {10.1080/09670262.2015.1095355},
  pages     = {47 -- 58},
  year      = {2016},
  abstract  = {Nutrient Induced Fluorescence Transients (NIFTs) have been shown to be a possible way of testing for the limiting nutrient in algal populations. In this study we tested the hypothesis that NIFTs can be used to detect a (co-)limitation for inorganic phosphorus (Pi) and CO2 in the green alga Chlamydomonas acidophila and that the magnitude of the NIFTs can be related to cellular P:C ratios. We show a co-limitation response for Pi and CO2 via traditional nutrient enrichment experiments in natural phytoplankton populations dominated by C. acidophila. We measured NIFT responses after a Pi- or a CO2-spike in C. acidophila batch cultures at various stages of Pi and inorganic C limitation. Significant NIFTs were observed in response to spikes in both nutrients. The NIFT response to a Pi-spike showed a strong negative correlation with cellular P:C ratio that was pronounced below 3 mmol P: mol C (equivalent to 0.2 pg P cell(-1)). Both cellular P and C content influenced the extent of the Pi-NIFT response. The NIFT response to a CO2-spike correlated to low CO2 culturing conditions and also had a negative correlation with cellular P content. A secondary response within the Pi-NIFT response was related to the CO2 concentration and potentially reflected co-limitation. In conclusion, NIFTs provided a quick and reliable method to detect the growth-limiting nutrient in an extremophile green alga, under Pi-, CO2- and Pi/CO2 (co-)limited growth conditions.},
  language  = {en}
}
@article{LischkeWeithoffWickhametal.2016,
  author    = {Lischke, Betty and Weithoff, Guntram and Wickham, Stephen A. and Attermeyer, Katrin and Großart, Hans-Peter and Scharnweber, Inga Kristin and Hilt, Sabine and Gaedke, Ursula},
  title     = {Large biomass of small feeders: ciliates may dominate herbivory in eutrophic lakes},
  series = {Journal of plankton research},
  volume    = {38},
  journal   = {Journal of plankton research},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0142-7873},
  doi       = {10.1093/plankt/fbv102},
  pages     = {2 -- 15},
  year      = {2016},
  abstract  = {The importance of ciliates as herbivores and in biogeochemical cycles is increasingly recognized. An opportunity to observe the potential consequences of zooplankton dominated by ciliates arose when winter fish kills resulted in strong suppression of crustaceans by young planktivorous fish in two shallow lakes. On an annual average, ciliates made up 38-76\% of the total zooplankton biomass in both lakes during two subsequent years. Consequently, ciliate biomass and their estimated grazing potential were extremely high compared with other lakes of various trophic states and depths. Grazing estimates based on abundance and size suggest that ciliates should have cleared the water column of small (<5 mu m) and intermediate (5-50 mu m) sized phytoplankton more than once a day. Especially, small feeders within the ciliates were important, likely exerting a strong top-down control on small phytoplankton. Particle-attached bacteria were presumably strongly suppressed by intermediate-sized ciliate feeders. In contrast to other lakes, large phytoplankton was proportionately very abundant. The phytoplankton community had a high evenness, which may be attributed to the feeding by numerous fast growing and selective ciliate species. Our study highlights ciliates as an important trophic link and adds to the growing awareness of the role of winter processes for plankton dynamics.},
  language  = {en}
}