Impact of behavior-altering chemicals on ecosystems

Laboratory fish that have swum in water containing traces of anti-anxiety drugs exhibit behavioral changes. They become more inclined to take risks and they eat more efficiently. Jonatan Klaminder is studying whether the same behavioral changes occur in contaminated lakes, and if so, what the implications are for the ecosystem.

Jonatan Klaminder

Associate Professor

Wallenberg Academy Fellow 2013

Umeå University

Research field:
How the behavior of organisms is impacted by the chemical composition of water.

Early 2013 saw the publication of a research article in Science that caused a great media stir around the world. The news was that perch living in water containing residues of Oxazepam, an anti-anxiety drug, become unafraid, greedy and livelier. Jonatan headed the research team behind these findings.

“In that study, and the next, we saw them turn into ‘superfish’ that eat more and live longer, at least in the lab.”

Now he is studying whether these behavioral changes also exist in real ecosystems. Thanks to funding from the Knut and Alice Wallenberg Foundation, Jonatan has set up his own research team at Umeå University, and has been able to broaden the scope of his experiments.

Jonatan gives a tour of a windowless room full of aquaria containing guppies. He explains that behavioral changes in a species can impact the ecological balance.

“Fear is a key survival factor. Fish that are not afraid leave the shoal and find more food but often get eaten by larger fish. If risk assessment in fish changes, this may affect their ability to survive and reproduce.”

“It is the total freedom to be able to tackle a question that has not been answered and be first. If it had not been for my admission as a Wallenberg Academy Fellow, I would not have been able to develop my own ideas and pursue an academic career here in Umeå.”

Tiny transmitters at the rear

The experiments Jonatan is overseeing are being conducted on various scales and degrees of complexity: an aquarium containing a single individual, one with many individuals, experimental ponds, and an entire lake system containing hundreds of perch. The plan is to monitor the fish for at least a year.

“Before they are released into the lake, we insert mini-transmitters at the rear end of the fish. The technique is called acoustic telemetry, and can be likened to an underwater GPS system. It was developed by the U.S. Navy, and the first consignment of these tiny transmitters went to us.”

Using the transmitters, the research team can monitor the fish and their movements in natural aquatic systems. They are released into fishless lakes in the area around Umeå.

“The first phase is to release perch that have been swimming in contaminated water in the lab. We also release fish that have been swimming in clean water, and see how differently they behave. Later on we plan to manipulate the lake water and see how behavior and the entire ecosystem changes.”

New treatment methods

Drug residues represent a growing category of pollutants throughout the world. More than 1,000 metric tons of pharmaceutical products are used each year in Sweden alone. Wastewater treatment plants pump residues out into Swedish rivers, lakes and streams. Oddly enough, there are no emission controls for pharmaceutical products.

“Wastewater treatment plants are built to remove nutrients such as phosphorus and nitrogen, not medicines. We hope to contribute knowledge to justify the development of new treatment methods.”

The chemical composition of water can also be affected by many other environmental pollutants and factors. This is also being studied as part of the project.

“One example is substances that come from contaminated sites such as mines. Behavioral changes have also been seen to result from changes in the pH of water. Acidification of lakes may in turn be due to elevated concentrations of carbon dioxide, more intensive forestry, and industrial emissions and discharges.”

Driven by an interest in fishing

Toxic organic pollutants began to be used on a large scale in the 1960’s. Environmental scientists quickly realized that many of these pollutants could cause behavioral disturbances in fish and other animals.

“But identifying behavioral changes in an aquarium over a period of a few minutes – what impact does this have in reality? This is a question I have long wanted to answer. The fact that, scientifically speaking, this is very hard to do makes it a great challenge.”

An enduring interest in the environment and fishing provides the impetus behind Jonatan’s research. He studied forest science at the Swedish University of Agricultural Sciences (SLU) in Umeå. He then gained a PhD from Umeå University and worked for a time as a postdoc at the University of Delaware in the U.S. His research is broad, as is the expertise of his team.

“I don’t like to get boxed into examining narrow, minor questions – I try to tackle the major issues. This naturally requires an interdisciplinary approach. No individual discipline, be it ecology, chemistry or physics, can solve the major problems in the field of environmental science. We have to adopt a multidisciplinary approach.”

Modeling behavior

The purpose of the project is to see whether or not fish behavior impacts the natural ecosystem. In their experiments the research team studies various behavioral changes, how the fish relate to one another, and a series of environmental factors.

Jonatan is collaborating closely with physicists working in the same building to develop modeling and analytical tools. Examples include software for a system of high-speed cameras capable of measuring behavioral effects over thousandths of a second.

“The ultimate aim is a model where we can link behavioral changes with effects in the ecosystem. It is quite possible that any changes in the behavior of the perch are insignificant in comparison with other environmental factors. But if we find the opposite is true, that there are impacts on the ecosystem, it is important to bring this to the fore.”

Text Susanne Rosén
Translation Maxwell Arding
Photo Magnus Bergström