Özet:

Seasonal variation in the relative contributions of littoral and pelagic food sources to the diets of open-water zooplankton and subsequent changes in their trophic positions were investigated with carbon and nitrogen Stable Isotope Analysis (SIA). We selected three open water stations as truly pelagic, but also influenced by littoral and riverine carbon sources. During each of the four seasons, integrated pelagic zooplankton samples were collected over 0-50 m depth intervals at each site along with seston in the size range 1.2-76 μm. In addition, vertical temperature profiles were measured. Littoral benthos from three sites along the main longitudinal axis of the lake was sampled to serve as a reference for tracing Lago Maggiore's littoral carbon isotopic signature. Among stations differences in δ13C and δ15N signatures of the different components of the pelagic food web, from seston to predatory zooplankton, were statistically non significant, thus confirming that allochthonous input may become important only after exceptional rainfall events. Changes in the δ13C pelagic baseline mirrored mean water temperature (0-50 m) seasonal changes. Similarly to Lake Geneva, they were likely driven by changes in carbon sources for phytoplankton growth during stratification and vertical water mixing. Differently from what observed for the other taxa, the role of littoral food sources was far from negligible (>50%) for diaptomids during winter and spring. We do not know however, whether such a result could be at least partially attributed to the heavy infestation by algal epibionts, or was consequent to the fact that these zooplankters may carry littoral carbon to the pelagial via horizontal migration. In winter, Bythotrephes longimanus was able to prey on Cyclops, thus occupying a trophic position comparable to that of planktivorous fish. Such a result confirms an ability of this visual, invertebrate predator to compete with young zooplanktivorous fish for food resources, similarly to what observed in lakes it recently invaded. VISCONTI, Anna, and Marina MANCA. 2011. “Seasonal Changes in the δ13C and δ15N Signatures of the Lago Maggiore Pelagic Food Web”. Journal of Limnology 70 (2):263-71. https://doi.org/10.4081/jlimnol.2011.263. More Citation Formats ACM ACS APA ABNT Chicago Harvard MLA Turabian Vancouver Download Citation Endnote/Zotero/Mendeley (RIS) BibTeX Downloads Download data is not yet available. Citations Similar Articles Barbara Leoni, Zooplankton predators and prey: body size and stable isotope to investigate the pelagic food web in a deep lake (Lake Iseo, Northern Italy) , Journal of Limnology: Vol. 76 No. 1 (2017) Baoli Wang, Cong-Qiang Liu, Xi Peng, Fushun Wang, Mechanisms controlling the carbon stable isotope composition of phytoplankton in karst reservoirs , Journal of Limnology: Vol. 72 No. 1 (2013) Rossana Caroni, Gary Free, Anna Visconti, Marina Manca, Phytoplankton functional traits and seston stable isotopes signature: a functional-based approach in a deep, subalpine lake, Lake Maggiore (N. Italy) , Journal of Limnology: Vol. 71 No. 1 (2012) Justine R. de Leon, Megumu Fujibayashi, Frances Mikayla Petilla, Bon Ivan Yumul, Milette U. Mendoza-Pascual, Rey Donne S. Papa, Noboru Okuda, Identification of aquatic consumer trophic pathways in four volcanic tropical lakes using fatty acid biomarkers , Journal of Limnology: Vol. 81 (2022) Marco Milardi, Jyrki Lappalainen, Suzanne McGowan, Jan Weckström, Can fish introductions alter nutrient cycles in previously fishless high-latitude lakes? , Journal of Limnology: Vol. 76 No. 1 (2017) Clara E. Moreno, Eirik Fjeld, Min K. Deshar, Espen Lydersen, Seasonal variation of mercury and δ15N in fish from Lake Heddalsvatn, southern Norway , Journal of Limnology: Vol. 74 No. 1 (2015) Mircea Alexe, Gheorghe Șerban, Andreea Baricz, Adrian-Ștefan Andrei, Adorján Cristea, Karina P. Battes, Mirela Cîmpean, Laura Momeu, Vasile Muntean, Sebastian A. Porav, Horia L. Banciu, Limnology and plankton diversity of salt lakes from Transylvanian Basin (Romania): A review , Journal of Limnology: Vol. 77 No. 1 (2018) Jianming Deng, Yunlin Zhang, Boqiang Qin, Xiaolong Yao, Yubing Deng, Trends of publications related to climate change and lake research from 1991 to 2015 , Journal of Limnology: Vol. 76 No. 3 (2017) Jong-Yun Choi, Kwang-Seuk Jeong, Geung-Hwan La, Seong-Ki Kim, Gea-Jae Joo, Sustainment of epiphytic microinvertebrate assemblage in relation with different aquatic plant microhabitats in freshwater wetlands (South Korea) , Journal of Limnology: Vol. 73 No. 1 (2014) Sonja Rigterink, Paula Echeverría-Galindo, Rodrigo Martínez-Abarca, Julieta Massaferro, Philipp Hoelzmann, Bernd Wünnemann, Andreas Laug, Liseth Pérez, Wengang Kang, Nicole Börner, Anja Schwarz, Ping Peng, Junbo Wang, Liping Zhu, Antje Schwalb, Sub-fossil chironomids as indicators of hydrological changes in the shallow and high-altitude lake Shen Co, Tibetan Plateau, over the past two centuries , Journal of Limnology: Vol. 81 (2022)

Anahtar Kelimeler: