@article{LeachBeisnerCareyetal.2018, author = {Leach, Taylor H. and Beisner, Beatrix E. and Carey, Cayelan C. and Pernica, Patricia and Rose, Kevin C. and Huot, Yannick and Brentrup, Jennifer A. and Domaizon, Isabelle and Grossart, Hans-Peter and Ibelings, Bastiaan W. and Jacquet, Stephan and Kelly, Patrick T. and Rusak, James A. and Stockwell, Jason D. and Straile, Dietmar and Verburg, Piet}, title = {Patterns and drivers of deep chlorophyll maxima structure in 100 lakes}, series = {Limnology and oceanography}, volume = {63}, journal = {Limnology and oceanography}, number = {2}, publisher = {Wiley}, address = {Hoboken}, issn = {0024-3590}, doi = {10.1002/lno.10656}, pages = {628 -- 646}, year = {2018}, abstract = {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.}, language = {en} } @article{MantzoukiBekliogluBrookesetal.2018, author = {Mantzouki, Evanthia and Beklioglu, Meryem and Brookes, Justin D. and Domis, Lisette Nicole de Senerpont and Dugan, Hilary A. and Doubek, Jonathan P. and Grossart, Hans-Peter and Nejstgaard, Jens C. and Pollard, Amina I. and Ptacnik, Robert and Rose, Kevin C. and Sadro, Steven and Seelen, Laura and Skaff, Nicholas K. and Teubner, Katrin and Weyhenmeyer, Gesa A. and Ibelings, Bastiaan W.}, title = {Snapshot surveys for lake monitoring, more than a shot in the dark}, series = {Frontiers in Ecology and Evolution}, volume = {6}, journal = {Frontiers in Ecology and Evolution}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {2296-701X}, doi = {10.3389/fevo.2018.00201}, pages = {5}, year = {2018}, language = {en} } @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{RusakTanentzapKlugetal.2018, author = {Rusak, James A. and Tanentzap, Andrew J. and Klug, Jennifer L. and Rose, Kevin C. and Hendricks, Susan P. and Jennings, Eleanor and Laas, Alo and Pierson, Donald C. and Ryder, Elizabeth and Smyth, Robyn L. and White, D. S. and Winslow, Luke A. and Adrian, Rita and Arvola, Lauri and de Eyto, Elvira and Feuchtmayr, Heidrun and Honti, Mark and Istvanovics, Vera and Jones, Ian D. and McBride, Chris G. and Schmidt, Silke Regina and Seekell, David and Staehr, Peter A. and Guangwei, Zhu}, title = {Wind and trophic status explain within and among-lake variability of algal biomass}, series = {Limnology and oceanography letters / ASLO, Association for the Sciences of Limnology and Oceanography}, volume = {3}, journal = {Limnology and oceanography letters / ASLO, Association for the Sciences of Limnology and Oceanography}, number = {6}, publisher = {Wiley}, address = {Hoboken}, issn = {2378-2242}, doi = {10.1002/lol2.10093}, pages = {409 -- 418}, year = {2018}, abstract = {Phytoplankton biomass and production regulates key aspects of freshwater ecosystems yet its variability and subsequent predictability is poorly understood. We estimated within-lake variation in biomass using high-frequency chlorophyll fluorescence data from 18 globally distributed lakes. We tested how variation in fluorescence at monthly, daily, and hourly scales was related to high-frequency variability of wind, water temperature, and radiation within lakes as well as productivity and physical attributes among lakes. Within lakes, monthly variation dominated, but combined daily and hourly variation were equivalent to that expressed monthly. Among lakes, biomass variability increased with trophic status while, within-lake biomass variation increased with increasing variability in wind speed. Our results highlight the benefits of high-frequency chlorophyll monitoring and suggest that predicted changes associated with climate, as well as ongoing cultural eutrophication, are likely to substantially increase the temporal variability of algal biomass and thus the predictability of the services it provides.}, language = {en} }