caa a22 4500 477067514 CHVBK 20180405111416.0 cr unu---uuuuu 170330e19960901xx s 000 0 eng 10.1007/BF02459492 doi (NATIONALLICENCE)springer-10.1007/BF02459492 Kmeť Tibor Department of Computer Science, Faculty of Natural Sciences, University of Education, Piaristická 10, 949 74, Nitra, Slovak Republic aut Material recycling in a closed aquatic ecosystem. I. Nitrogen transformation cycle and preferential utilization of ammonium to nitrate by phytoplankton as an optimal control problem [Elektronische Daten] [Tibor Kmeť] A mathematical model of the nitrogen transformation cycle in an aquatic environment is studied. Using Pontryagin's maximum principle, a preferential utilization of ammonium to nitrate by phytoplankton is explained and verified by experimental data. A multiparameter bifurcation is given. The model was found to have four types of equilibrium sets. It is shown that a Hopf bifurcation may occur. Society for Mathematical Biology, 1996 Bulletin of Mathematical Biology Kluwer Academic Publishers 58/5(1996-09-01), 957-982 0092-8240 58:5<957 1996 58 11538 https://doi.org/10.1007/BF02459492 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02459492 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Kmeť Tibor Department of Computer Science, Faculty of Natural Sciences, University of Education, Piaristická 10, 949 74, Nitra, Slovak Republic aut NATIONALLICENCE 773 0- Bulletin of Mathematical Biology Kluwer Academic Publishers 58/5(1996-09-01), 957-982 0092-8240 58:5<957 1996 58 11538 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer