Data from: Microcystins bioaccumulate but do not biomagnify in an experimental aquatic food chain

Microcystins-common hepatotoxins produced by cyanobacteria—have been
detected in a wide range of organisms, though research examining the
trophic transfer of microcystins and whether microcystins bioaccumulate or
biomagnify in food webs has generated contradictory results. Here, we
explored the trophic transfer of microcystins from the herbivorous water
flea, Daphnia pulex, to the predatory larvae of a damselfly, Enallagma sp.
We tested the hypotheses that microcystins transfer from the tissue of
herbivorus zooplankton to that of predatory invertebrates and that these
toxins biomagnify across trophic levels. We also assessed the relative
contribution of toxin transfer from the gut and tissue of Daphnia pulex to
Enallagma sp. We found that microcystins are effectively sequestered in
the tissue of Daphnia pulex, and that these sequestered toxins are then
transferred to the tissue of Enallagma sp. The contribution of gut
contents to toxin transfer was negligible. Contrary to the pattern
predicted by biomagnification, we found that the concentration of
microcystins decreased with increasing trophic levels. Our results support
the hypothesis that microcystins can be transferred trophically, but do
not support the hypothesis that microcystins biomagnify from lower to
higher trophic levels. Conversly, we observe biodilution in this system.
These results have consequences for the impact of microcystins across
trophic levels in a changing world with increasing intensity and duration
of harmful algal blooms.