Using Damselflies to Test Ecosystem Effects of Algal Blooms

Researchers at the Cleveland Museum of Natural History, using a digital microscopy station purchased through an NSF instrumentation grant, have found that even minor blooms of algae in Lake Erie negatively affect survival rates of insect populations.

This work enhances our understanding of a regionally important aquatic ecosystem and its health, as well as our knowledge of the impact of algal blooms.

Algae in the Lake Erie watershed periodically create large blooms that produce chemicals detrimental to life in the water. Large blooms can lead to fish die-offs and also impact area economies by shutting down recreational activities.

Museum researchers took pictures at microscopic levels of lab-reared, developing damselfly larvae and tested for various indicators of environmental stress such as growth rate, survival and degree of bodily asymmetry. They found that the flies' survival rates declined in the presence of high levels of microcystin (a common algal bloom chemical). The flies' growth rate decreased as well.

The researchers also found a drop in the survival rates of insects that preyed on flies raised in a microcystin-rich environment.

The computerized imaging allowed for accurate and efficient measurements over a period of months, which would be nearly impossible using traditional hand measurements.