What is up with the algal toxins?

By: Lesly Hernandez

Recently harmful algal blooms have been increasing worldwide. They are a threat to aquatic species and might also be harmful to humans’ health. Some cyanobacteria produce microcystins (MC) which is a toxin that inhibit the activity of protein phosphatases. MC is accumulated by different aquatic animals which then transfer the toxic to other animals after consumption. The research describes the movement of algal toxins from aquatic food webs into riparian food webs by measuring the MC concentrations in different animals (mayfly, nidges, caddisflies, spiders, and Prothonotary Warblers). They also analyzed the concentrations between aquatic and terrestrial prey to check if growth rates are affected by the exposure to MC. The highest toxin concentrations were found in spiders and in the livers of nestling warblers. Aquatic insects had twenty times higher levels of MC than terrestrial prey which explains how riparian consumers are exposed to the toxins. Furthermore, MC levels did not correlate with warbler body condition or growth rate. The research shows that algal toxins are not only present in aquatic life but also in other food webs. We have to do something to stop the algal toxins from being passed on from aquatic systems to terrestrial food webs. More research needs to be done to improve the understanding of risks to humans and other living organisms that consume products that have algal toxins.

Figure 1. Concentrations of the algal toxin MC among terrestrial insects, aquatic emerging insects and riparian consumers from the James River Estuary in Virginia (Moy et al., 2016, http://pubs.acs.org.tamiu.idm.oclc.org/doi/pdf/10.1021/acs.est.6b02760).

Reference

Moy, N. J., J. Dodson, S.J. Tassone, P.A. Bukaveckas, and L. P. Bulluck. 2016. Biotransport of Algal Toxins to Riparian Food Webs. Environmental Science & Technology. 50:10007-10014