Geographical patterns in cyanobacteria distribution: climate influence at regional scale.
Cyanobacteria are a component of public health hazards in freshwater environments because of their potential as toxin producers. Eutrophication has long been considered the main cause of cyanobacteria outbreak and proliferation, whereas many studies emphasized the effect of abiotic parameters (mainly temperature and light) on cell growth rate or toxin production. In view of the growing concerns of global change consequences on public health parameters, this study attempts to enlighten climate influence on cyanobacteria at regional scale in Brittany (NW France). The results show that homogeneous cyanobacteria groups are associated with climatic domains related to temperature, global radiation and pluviometry, whereas microcystins (MCs) occurrences are only correlated to local cyanobacteria species composition. As the regional climatic gradient amplitude is similar to the projected climate evolution on a 30-year timespan, a comparison between the present NW and SE situations was used to extrapolate the evolution of geographical cyanobacteria distribution in Brittany. Cyanobacteria composition should shift toward species associated with more frequent Microcystins occurrences along a NW/SE axis whereas lakes situated along a SW/NE axis should transition to species (mainly Nostocales) associated with lower MCs detection frequencies.
Limnologie sarl, 16 rue Paul Langevin, Rennes 35200, France. fred.pitois@limnosphere.com.
Frédéric
F
Pitois
Limnologie sarl, 16 rue Paul Langevin, Rennes 35200, France. isabelle.thoraval@limnosphere.com.
Isabelle
I
Thoraval
Ecole des Hautes Etudes en Santé Publique de Rennes (EHESP), Sorbonne Paris Cité, Avenue du Professeur Léon Bernard-CS 74312, Rennes Cedex 35043, France. estelle.baures@ehesp.fr.
Estelle
E
Baurès
Ecole des Hautes Etudes en Santé Publique de Rennes (EHESP), Sorbonne Paris Cité, Avenue du Professeur Léon Bernard-CS 74312, Rennes Cedex 35043, France. olivier.thomas@ehesp.fr.
Olivier
O
Thomas
D002980:Climate; D000458:Cyanobacteria / Q000145:classification / Q000302:isolation & purification*; D004784:Environmental Monitoring; D005602:France; D060106:Lakes; D052998:Microcystins / Q000032:analysis; D014873:Water Pollutants / Q000032:analysis
D052998:Microcystins; D014873:Water Pollutants