Browsing by Author "Burnet, Sarah"
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- Can space-for-time-substitution surveys represent zooplankton biodiversity patterns and their relationship to environmental drivers?Publication . Stockwell, Jason; Ivanick, Lia; Chiapella, Ariana; Vichi, Cecilia; Grossart, Hans-Peter; Zagarese, Horacio; Diovisalvi, Nadia; Odriozola, Mariana; Gideon, Gal; Geraldes, Ana Maria; Christoffersen, Kirsten Seestern; Sarvala, Jouko; Blank, Kätlin; Beklioğlu, Meryem; Kainz, Martin; Bruel, Rosalie; Ger, Kemal Ali; Matsuzaki, Shin-Ichiro; Khan, Samiullah; Nejstgaard, Jens; Znachor, Petr; Seda, Jaromír; Obertegger, Ulrike; Salmaso, Nico; García-Girón, Jorge; Leoni, Barbara; Jeppesen, Erik; Tavşanoğlu, Ülkü Nihan; Rusanovskaya, Olga O.; Tartarotti, Barbara; Dur, Gaël; Kuczyńska-Kippen, Natalia; Dondajewska-Pielka, Renata; Eyto, Elvira de; Thackeray, Stephen; Garcia de Souza, Javier R.; Rusak, James A.; Moe, Jannicke; Figary, Stephanie; May, Linda; Gunn, Iain; Doubek, Jonathan; Symons, Celia C.; Burnet, Sarah; Lepori, Fabio; Alcocer, Javier; Fernández, Rocío; Oseguera, Luis A.; Verburg, Piet; Fontanarrosa, María SoledadSpace-for-Time-Substitution surveys (SFTS) are commonly used to describe zooplankton community dynamics and to determine lake ecosystem health. SFTS surveys typically combine single point observations from many lakes to evaluate the response of zooplankton community structure and dynamics (e.g., species abundance and biomass, diversity, demographics and modeled rate processes) to spatial gradients in hypothesized environmental drivers (e.g., temperature, nutrients, predation), in lieu of tracking such responses over long time scales. However, the reliability and reproducibility of SFTS zooplankton surveys have not yet been comprehensively tested against empirically-based community dynamics from longterm monitoring efforts distributed worldwide. We use a recently compiled global data set of more than 100 lake zooplankton time series to test whether SFTS surveys can accurately capture zooplankton diversity, and the hypothesized relationship with temperature, using simulated SFTS surveys of the time series data. Specifically, we asked: (1) to what degree can SFTS surveys capture observed biodiversity dynamics; (2) how does timing and duration of sampling affect detected biodiversity patterns; (3) does biodiversity ubiquitously increase with temperature across lakes, or vary by climate zone or lake type; and (4) do results from SFTS surveys produce comparable biodiversity-temperature relationship(s) to empirical data within and among lakes? Testing biodiversity-ecosystem function (BEF) relationships, and the drivers of such relationships, requires a solid data basis. Our work provides a global perspective on the design and usefulness of (long-term) zooplankton monitoring programs and how much confidence we can place in the zooplankton biodiversity patterns observed from SFTS surveys.
- The effects of hypoxia on zooplankton population estimates and migration in lakesPublication . Goldfarb, Sadye K.; Doubek, Jonathan; Geraldes, Ana Maria; Bartrons, Mireia; Berger, Stella; Brentrup, Jannifer; Brucet, Sandra; Burnet, Sarah; Caputo Galarce, Luciano; Carey, Cayelan C.; Christoffersen, Kirsten Seestern; Eyto, Elvira de; Dur, Gaël; Erdoğan, Şeyda; Erina, Oxana; Grossart, Hans-Peter; Kainz, Martin; Kankılıç, Gökben Başaran; Khan, Sami; Leoni, Barbara; Lepori, Fabio; McCarthy, Valerie; Nava, Veronica; Nejstgaard, Jens; Obertegger, Ulrike; Ogorelec, Ziga; Ozen, Arda; Pascual, Maria; Paterson, Michael; Patelli, Martina; Qiu, Qianlinglin; Richardson, David; Sepulveda-Jauregui, Armando; Silva, Lorena; Straile, Dietmar; Tartarotti, Barbara; Tavşanoğlu, Ülkü Nihan; Tereshina, Maria; Umaña-Villalobos, Gerardo; Walles, Tim; Wander, Heather; Wurtsbaugh, Wayne; Stockwell, JasonMany zooplankton species typically exhibit diel vertical migration (DVM), where zooplankton migrate from the hypolimnion to the epilimnion of lakes at night. Zooplankton exhibit this behavior to avoid visual predators and UV radiation by remaining in the bottom waters during the day and ascending to the surface waters to feed on phytoplankton at night. However, hypoxic conditions in the hypolimnion of lakes mayinterfere with DVM and force zooplankton to increase diel horizontal migration (DHM) to find predation refuge in littoral zones. Climate change and eutrophication are expected to increase the prevalence and severity of hypoxic conditions worldwide and thereby possibly alter zooplankton migration patterns. We hypothesize that hypoxia will force zooplankton to shift their migration patterns from predominantly DVM to DHM to avoid oxygen-depleted bottom waters. To test our hypothesis, we are conducting a standardized global sampling program to test whether pelagic, full water column estimates of zooplankton are greater at night versus the day under hypolimnetic hypoxic versus oxic conditions. Participants are aiming to sample at least one lake with an oxic hypolimnion and one lake with a hypoxic hypolimnion during the thermally-stratified period at midday and midnight. With our global dataset (currently expecting about 60 lakes in 22 countries), our goal is to improve our understanding of how global change may alter zooplankton migration behavior and patterns in lakes.