Cyanobacteria blooms induce embryonic heart failure in an endangered fish species

Session: Harmful Algal Blooms: From Ecosystem Drivers to Ecosystem Impacts (4)

Xuexiu Chang, Yunnan University / University of Windsor, [email protected]
Jinmei zi, Yunnan University, [email protected]
Hugh MacIsaac, University of Windsor, [email protected]
Xiaofu Pan, Kunming Institute of Zoology, Chinese Academy of Sciences, [email protected]

Abstract

Cyanobacterial blooms drive water-quality and aquatic-ecosystem deterioration in eutrophic lakes owing to harmful, secondary metabolites. The response of fish exposed to these cyanobacterial chemicals remains largely unknown. We employed an endangered fish species (Sinocyclocheilus grahami) in Dianchi Lake, China, to evaluate the risk of cell-free exudates (MaE) produced by a dominant cyanobacterium (Microcystis aeruginosa) on embryo development, as well as the molecular mechanisms responsible. MaE caused a reduction of fertilization (35.4%) and hatching (15.5%) rates, and increased mortality rates (?90.0%) and malformation rate (27.6%), typically accompanied by heart failure.  Proteomics analysis revealed that the two greatest changed proteins – protein S100A1 (over-expressed 26 times compared with control) and myosin light chain (under-expressed 25 fold) – are closely associated with heart function. Heart failure was associated with calcium ion imbalance and malformed cardiac structure. We conclude that harmful secondary metabolites from cyanobacteria may adversely affect embryo development in this endangered fish, and possibly contribute to its disappearance and unsuccessful recovery in this lake.