# Use of a mathematical model in the analysis of survival of Daphnia magna exposed to toxicants (Articolo in rivista)

- Type
- Articolo in rivista (Classe)
- Prodotto della ricerca (Classe)

- Label
- Use of a mathematical model in the analysis of survival of Daphnia magna exposed to toxicants (Articolo in rivista) (literal)

- Anno
- 2003-01-01T00:00:00+01:00 (literal)

- Alternative label
- Santojanni A. 1, Rossolini G. 2, Gorbi G. 3, Piantanelli L. 2, Sartore F.3 (2003)(literal)
**Use of a mathematical model in the analysis of survival of Daphnia magna exposed to toxicants**

- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
- Santojanni A. 1, Rossolini G. 2, Gorbi G. 3, Piantanelli L. 2, Sartore F.3 (literal)

- Pagina inizio
- 2357 (literal)

- Pagina fine
- 2364 (literal)

- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#altreInformazioni
- Impact Factor: 1.812. QUOTED FROM INTRODUCTION - Discharge of chemicals is a well known problem causing pollution of superficial waters. In order to prevent risks due to discharge of toxic chemicals, tests evaluating acute and chronic toxicity on aquatic organisms can be performed. In aquatic toxicology, species of the genus Daphnia, mainly Daphnia magna and Daphnia pulex are commonly used. Acute toxicity tests on these organisms last 24-48 hours and examine the effects of toxicants on survival; chronic toxicity tests require at least 21 days of exposure and also examine effects on fecundity and growth [ref]. (literal)

- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
- 37 (literal)

- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#descrizioneSinteticaDelProdotto
- QUOTED FROM INTRODUCTION - In chronic toxicity tests, mortality in the cohorts can be examined on the basis of survival curves. The percentage of surviving individuals is checked and plotted over time, often up to the extinction of the cohort. Different shape can be observed in these curves: that is well known in survival curves obtained from experiments with Daphnia magna fed with different amount of food [ref]. In a survival curve with a very rectangular shape, a steady value of surviving percentage close to 100% is recorded in a first time interval, with a subsequent sudden and very sharp decrease. Most individuals of the cohort die during this relatively short period: that means the cohort is formed by individuals who have - at the beginning of the test - about the same probability to reach their potential maximal age in that specific environment, and maintain this probability over time exposure up to death. Hence, departures from a very rectangular shape are thought to be due to some degree of inter-individual heterogeneity, which can be related with genetic and/or environmental factors. In the case of a cohort of Daphnia magna employed in a chronic test, genetic differences between individuals can be associated to different probability of dying [ref]; among environmental factors, maternal effect (i.e. lipid stores) could play a role in the inter-individual heterogeneity and, interestingly, has a link with survival [ref]. (literal)

- Note
- ISI Web of Science (WOS) (literal)

- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
- 1 CNR - ISMAR, 2 Centro di Biochimica, Dip. di Ricerche Gerontologiche INRCA Ancona, 3 UNI Parma (literal)

- Titolo
- Use of a mathematical model in the analysis of survival of Daphnia magna exposed to toxicants (literal)

- Abstract
- Chronic toxicity tests carried out on species of the genus Daphnia (Crustacea:Cladocera) are bioassays commonly used in ecotoxicology. Mortality in the cohorts exposed to toxicants can be examined by the analysis of survival curves. The shape of these curves may be very different because of inter-individual heterogeneity: the less rectangular is the shape the more different is the probability of dying of daphnids in the cohort. Aim of this paper is to analyze the characteristics in particular the shape of survival curves of cohorts of Daphnia magna exposed to heavy metals in chronic toxicity tests. Experimental curves were fitted by a mathematical model recently proposed, which puts emphasis just on this heterogeneity, described by the parameter of the model S0. The information contained in S0 is very useful for the present purposes: the higher the value of S0 the less rectangular the shape of the curve and, as a consequence, the higher the age-at-death heterogeneity of the cohort is thought to be. The model contains a second parameter, omega, representing the maximum potential ability of the individuals to survive in a specific environment and is related with the maximal life span. The model fitted well the survival curves in most cases and both S0 and omega showed statistically different values between treatments, useful for comparisons. It was concluded that S0 provides a quantitative estimation of curve rectangularization, useful to check different sensitivities to a specific toxicant concentration among daphnids belonging to the same cohort, while omega provides an estimate of maximal life span. (literal)

- Prodotto di
- Marine science institute (ISMAR) (Istituto)

- Autore CNR
- ALBERTO SANTOJANNI (Unità di personale interno)

- Insieme di parole chiave

#### Incoming links:

- Prodotto
- Marine science institute (ISMAR) (Istituto)

- Autore CNR di
- ALBERTO SANTOJANNI (Unità di personale interno)

- Insieme di parole chiave di