Hands-on research with Chironomus riparius

Sitting in the lab in front of a sewing machine was not exactly what I imagined of doing when I started my PhD in the group of aquatic ecotoxicology. However, sewing two hundred miniature mosquito nets was required before I finished my thesis.

Inna and Greta sewing mosquito nets. Photo by Inna Nybom
Inna and Greta sewing mosquito nets. Photo by Inna Nybom

My PhD relates to activated carbon, porous carbon material, which has been studied as a new remediation method for contaminated water ecosystems. Due to its wide surface area, activated carbon can bind numerous contaminants efficiently and lock them in the bottom sediments in a way that they are now longer available for organisms living in the area. Reduced bioavailability of the contaminants for benthic organisms reduces also their transport in the food chain and in time this can reduce the contaminant load to humans from fish consumption. However, both old and new remediation methods, where something is removed or added to the natural ecosystem, can disturb the balance in the field, at least temporarily. Therefore, in this study also direct adverse effects of activated carbon to the benthic organisms were followed.

In our resent work the effects of activated carbon were studied on midge Chironomus riparius. Chironomus riparius is a nonbiting midge, with a four-stage life cycle: egg, larva, pupa and adult midge. Larvae is living in the sediment, and they were grown in activated carbon containing contaminated sediment. After few weeks the larvae develops to flying adult stage, and this is where the mosquito nets come in handy. In order to follow the effects of different exposures to the adult stages, 180 small beakers were sorted on the table and covered with individual mosquito nets, food was provided three times a week and all beakers were monitored daily. All the effort payed off when we finally got the results! We observed that adding activated carbon to the sediment reduces the contamination level not only in the larvae stages but also in the flying adult stages exposed during the larvae stage. We know that the aquatic insects going through metamorphosis can transport the contaminants buried in the bottom sediments to the terrestrial food webs, and our result indicates that adding activated carbon to the sediment may reduce this transport of contaminants! Amongst this we discovered many other cool things, which are published in details in Environmental Science and Technology (2016, 50[10] 5252–5260, DOI: 10.1021/acs.est.6b00991). Check it out, if you are interested in finding out more!

A life cycle of Chironomus riparius
A life cycle of Chironomus riparius. Photo by Inna Nybom

I had a great time working in the croup of aquatic ecotoxicology, but now new adventures are ahead. My PhD project came to an end on December last year when I defended my thesis. The most I am going to miss all the great people I got to work with. A great group of excellent scientist with a catching enthusiasm, innovative to come up with the ideas of 200 miniature mosquito nets, and crazy enough to actually sew them with you!