Publication Date:
2021-05-19
Description:
The phytoplankton communities and the production of cyanobacterial toxins were
investigated in two alkaline Kenyan crater lakes, Lake Sonachi and Lake Simbi. Lake Sonachi
was mainly dominated by the cyanobacterium Arthrospira fusiformis, Lake Simbi by
Arthrospira fusiformis and Anabaenopsis abijatae. The phytoplankton biomasses measured
were high, reaching up to 3159 mg l-1 in L. Sonachi and up to 348 mg l-1 in L. Simbi. Using
HPLC techniques, in L. Sonachi one structural variant of the hepatotoxin microcystin
(microcystin-RR) was found in L. Sonachi and four variants (microcystin- LR, -RR, -LA and
-YR) were identified in L. Simbi. The neurotoxin anatoxin-a was found in both lakes. To our
knowledge this is the first evidence of cyanobacterial toxins in L. Sonachi and L. Simbi. Total
microcystin concentrations varied from 1.6 to 12.0 μg microcystin-LR equivalents g-1 DW in
L. Sonachi and from 19.7 to 39.0 μg microcystin-LR equivalents g-1 DW in L. Simbi.
Anatoxin-a concentrations ranged from 0.5 to 2.0 μg g-1 DW in L. Sonachi and from 0 to 1.4
μg g-1 DW in L. Simbi. In a monocyanobacterial strain of Arthrospira fusiformis, isolated
from L. Sonachi, microcystin-YR and anatoxin-a were produced. The concentrations found
were 2.2 μg microcystin g-1 DW and 0.3 μg anatoxin-a g-1 DW. This is the first study showing
Arthrospira fusiformis as producer of microcystins and anatoxin-a. Since Arthrospira
fusiformis occurs in mass developments in both lakes, a health risk for wildlife can be
expected.
Description:
Unpublished
Keywords:
Bacteria
;
Phytoplankton
;
Biological poisons
;
Toxicology
;
Inland waters
;
Freshwater lakes
;
Poisonous organisms
Repository Name:
AquaDocs
Type:
Report Section
,
Not Known
Format:
pp.106-126
