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Seasonal, inter‐annual and long term variation in top–down versus bottom–up regulation of primary production
Author(s) -
Kerimoglu Onur,
Straile Dietmar,
Peeters Frank
Publication year - 2013
Publication title -
oikos
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.672
H-Index - 179
eISSN - 1600-0706
pISSN - 0030-1299
DOI - 10.1111/j.1600-0706.2012.20603.x
Subject(s) - phytoplankton , productivity , environmental science , primary producers , ecosystem , top down and bottom up design , ecology , term (time) , zooplankton , nutrient , primary productivity , atmospheric sciences , oceanography , biology , geology , computer science , physics , software engineering , quantum mechanics , economics , macroeconomics
Environmental change strongly affects primary productivity of ecosystems via modifying bottom–up and top–down regulation of primary producers. Here we present a novel approach to quantify the relative importance of regulating factors in natural systems over various time scales: we calculated daily effect sizes of major factors affecting phytoplankton growth during the spring bloom period during almost three decades of lake oligotrophication using numerical experiments with a data based simulation model. We show that with oligotrophication the regulation of spring phytoplankton shifts from primarily top–down to bottom–up, and that the changes in regulation are non‐linearly related to the nutrient (phosphorus) concentrations. Our findings indicate that long‐term changes in top–down regulation cannot be understood without considering multiple herbivore taxa, here, microzooplankton (ciliates) and mesozooplankton (daphnids). We further demonstrate that bottom–up and top–down regulation are not independent from each other and that their interaction is time‐scale dependent.