US EPA

6332098 

Journal Article 

Akinetes and ancient DNA reveal toxic cyanobacterial recurrences and their potential for resurrection in a 6700-year-old core from a eutrophic lake 

Legrand, B; Miras, Y; Beauger, A; Dussauze, M; Latour, D 

2019 

1 

Science of the Total Environment
ISSN: 0048-9697
EISSN: 1879-1026 

Elsevier B.V. 

687 

1369-1380 

English 

31412470 

10.1016/j.scitotenv.2019.07.100 

WOS:000480316300131 

In order to evaluate the recurrence of toxic cyanobacterial blooms and to determine the survival capabilities of the resistance cells through time, a sedimentary core spanning 6700 years was drilled in the eutrophic Lake Aydat. A multiproxy approach (density, magnetic susceptibility, XRF, pollen and non-pollen palynomorph analyses), was used initially to determine the sedimentation model and the land uses around the lake. Comparison with the akinete count revealed that Nostocales cyanobacteria have been present in Lake Aydat over a six thousand year period. This long-term cyanobacterial recurrence also highlights the past presence of both the anaC and mcyB genes, involved in anatoxin-a and microcystin biosynthesis, respectively, throughout the core. The first appearance of cyanobacteria seems to be linked to the natural damming of the river, while the large increase in akinete density around 1800 cal.yr BP can be correlated with the intensification of human activities (woodland clearance, crop planting, grazing, etc.) in the catchment area of the lake, and marks the beginning of a long period of eutrophication. This first investigation into the viability and germination potential of cyanobacteria over thousands of years reveals the ability of intact akinetes to undergo cell divisions even after 1800 years of sedimentation, which is 10 times longer than previously observed. This exceptional cellular resistance, coupled with the long-term eutrophic conditions of this lake, could partly explain the past and current recurrences of cyanobacterial proliferations. 

Akinete; Ancient akinete germination; Past bloom; Past toxic potential; Sediment; Biochemistry; Catchments; Cell proliferation; Cultivation; Eutrophication; Land use; Magnetic susceptibility; River pollution; Sediments; Akinete; Ancient akinete germination; Germination potential; Multiproxy approach; Past bloom; Sedimentation model; Toxic cyanobacterial blooms; Toxic potential; Lakes; anatoxin a; ancient DNA; microcystin; tropane derivative; cyanobacterium; DNA; eutrophic environment; eutrophication; germination; lake water; sediment core; sedimentation; toxic material; akinete; anaC gene; Article; bacterial cell; bacterial gene; bacterial viability; biosynthesis; catchment; cell count; cell density; cell division; cell proliferation; controlled study; cyanobacterium; environmental impact; eutrophication; germination; lake; land use; mcyB gene; nonhuman; Nostocales; priority journal; sedimentation; X ray fluorescence spectrometry; cyanobacterium; environmental monitoring; eutrophication; genetics; lake; microbiology; recurrent disease; season; sediment; water pollution; Cyanobacteria; Nostocales; Cyanobacteria; Environmental Monitoring; Eutrophication; Geologic Sediments; Lakes; Microcystins; Recurrence; Seasons; Tropanes; Water Pollution