Effect of Microcystis aeruginosa–Associated Microcystin-LR on the Survival of 2 Life Stages of Freshwater Mussel (Lampsilis siliquoidea)

Abstract

Microcystin‐LR is a toxin commonly produced by the cyanobacterium Microcystis aeruginosa. It is present in harmful algal blooms and is a concern for both human and environmental health in Canadian freshwater systems. Previous studies have investigated the toxicity of microcystin‐LR to other organisms such as fish; however, it is important to assess its toxicity to native freshwater mussels (family Unionidae), which are considered imperiled. The present study examined the toxicity of microcystin‐LR to fatmucket mussels (Lampsilis siliquoidea) at 2 different life stages. Juvenile mussels were exposed to microcystin‐LR in a 28‐d chronic test, and glochidia underwent a 72‐h acute toxicity test. There was no significant relationship between glochidia viability and microcystin‐LR concentration. The median lethal concentration (LC50) value for juvenile mussels after 28 d of exposure was 2.1 µg/L. To determine the environmental relevance of the observed toxicity, an environmental exposure distribution was created using Canadian and Canadian–US Great Lakes microcystin measurements. The 28‐d LC50 value (2.1 µg/L) was greater than those values that occurred in the environment 95% of the time; however, the LC10 (0.45 µg/L) and LC25 (0.97 μg/L) values were not greater than the measured microcystin environmental values. This finding indicates that microcystins may exert toxic effects on juvenile mussels at environmentally relevant concentrations. Further investigation should be considered in terms of prolonged exposure to persistent microcystin‐LR, and toxicity to sensitive species at different life stages. Environ Toxicol Chem 2019;38:2137–2144. © 2019 SETAC.

Cyanotoxins within and Outside of Microcystis aeruginosa Cause Adverse Effects in Rainbow Trout (Oncorhynchus mykiss)

“…Harmful algal blooms dominated by Microcystis are a global concern as their frequency and severity continue to impact the ecological and socioeconomic value of freshwater ecosystems. − These blooms typically produce cyanotoxins including microcystins, a family of over 250 congeners that can cause lethality and health impairment in humans and wildlife. − …”

An efficient and affordable laboratory method to produce and sustain high concentrations of microcystins by Microcystis aeruginosa

“…Microcystins are cyclic heptapeptides capable of causing death to humans [9], animals [10], and aquatic invertebrates [11,12]. Upon ingestion by humans and animals, microcystins are transported to the liver where they cause toxicity by inhibiting protein phosphatases 1 and 2A [13].…”

Dissolved Algal Toxins along the Southern Coast of British Columbia Canada

“…MCs are well-studied cyanotoxins (e.g., [ 14 , 26 , 27 ]) with over 270 congeners [ 28 , 29 ], and are produced by numerous genera of cyanobacteria, including Anabaena ( Dolichospermum ), Aphanizomenon , Planktothrix [ 30 ], and commonly by Microcystis [ 31 ]. They are potent hepatotoxins that are linked to changes in gene expression, physiology, and morphology in numerous animals, including fish [ 4 , 32 , 33 , 34 , 35 , 36 ], invertebrates [ 36 , 37 , 38 , 39 , 40 ], as well as marine and terrestrial mammals [ 20 , 41 ]. In addition to causing severe liver damage, they can induce a variety of sub-lethal effects in fish [ 42 ], which include cardiorespiratory function [ 43 , 44 ], reproductive and endocrine function [ 45 , 46 , 47 , 48 ], growth rate [ 49 ], whole animal condition [ 50 ], swimming performance [ 51 ], and immunity [ 52 , 53 , 54 ].…”