title: Modelling the Stoichiometric Regulation of C-Rich Toxins in Marine Dinoflagellates.
abstract: Toxin production in marine microalgae was previously shown to be tightly coupled with cellular stoichiometry. The highest values of cellular toxin are in fact mainly associated with a high carbon to nutrient cellular ratio. In particular, the cellular accumulation of C-rich toxins (i.e., with C:N > 6.6) can be stimulated by both N and P deficiency. Dinoflagellates are the main producers of C-rich toxins and may represent a serious threat for human health and the marine ecosystem. As such, the development of a numerical model able to predict how toxin production is stimulated by nutrient supply/deficiency is of primary utility for both scientific and management purposes. In this work we have developed a mechanistic model describing the stoichiometric regulation of C-rich toxins in marine dinoflagellates. To this purpose, a new formulation describing toxin production and fate was embedded in the European Regional Seas Ecosystem Model (ERSEM), here simplified to describe a monospecific batch culture. Toxin production was assumed to be composed by two distinct additive terms; the first is a constant fraction of algal production and is assumed to take place at any physiological conditions. The second term is assumed to be dependent on algal biomass and to be stimulated by internal nutrient deficiency. By using these assumptions, the model reproduced the concentrations and temporal evolution of toxins observed in cultures of Ostreopsis cf. ovata, a benthic/epiphytic dinoflagellate producing C-rich toxins named ovatoxins. The analysis of simulations and their comparison with experimental data provided a conceptual model linking toxin production and nutritional status in this species. The model was also qualitatively validated by using independent literature data, and the results indicate that our formulation can be also used to simulate toxin dynamics in other dinoflagellates. Our model represents an important step towards the simulation and prediction of marine algal toxicity.
authors.affiliation: Department of Biological, Geological and Environmental Sciences (BiGeA)-University of Bologna, Via Sant'Alberto 163, 48123 Ravenna, Italy; Plymouth Marine Laboratory, Prospect Place, The Hoe, PL1 3DH Plymouth, United Kingdom.
authors.forename: Adriano
authors.initials: A
authors.lastname: Pinna
authors.affiliation: Department of Biological, Geological and Environmental Sciences (BiGeA)-University of Bologna, Via Sant'Alberto 163, 48123 Ravenna, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Pezzolesi
authors.affiliation: Department of Biological, Geological and Environmental Sciences (BiGeA)-University of Bologna, Via Sant'Alberto 163, 48123 Ravenna, Italy.
authors.forename: Rossella
authors.initials: R
authors.lastname: Pistocchi
authors.affiliation: Department of Biological and Environmental Sciences-University of Messina, Viale Ferdinando d'Alcontres 31, 98166 S. Agata, Messina, Italy.
authors.forename: Silvana
authors.initials: S
authors.lastname: Vanucci
authors.affiliation: Plymouth Marine Laboratory, Prospect Place, The Hoe, PL1 3DH Plymouth, United Kingdom; National Centre for Earth Observation (NCEO), Plymouth Marine Laboratory, Plymouth, United Kingdom.
authors.forename: Stefano
authors.initials: S
authors.lastname: Ciavatta
authors.affiliation: Plymouth Marine Laboratory, Prospect Place, The Hoe, PL1 3DH Plymouth, United Kingdom.
authors.forename: Luca
authors.initials: L
authors.lastname: Polimene
mesh_terms: D018533:Biomass; D004141:Dinoflagellida / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D057097:Harmful Algal Bloom / Q000502:physiology; D008387:Marine Toxins / Q000032:analysis / Q000378:metabolism*; D015233:Models, Statistical; D012623:Seawater / Q000737:chemistry / Q000382:microbiology
chemical_list: D008387:Marine Toxins