Can pollutants like pesticides and micro plastic affect the swimming behavior of Daphnia?
The ability to swim is important for crustacean zooplankton species including Daphnia as it allows for movements in the water column in relation to predators, food particles and oxygen. Swimming is possible due to the long antennas that features the front part of all Daphnia species and the swimming direction is often set by natural chemical cues, density of particles and by light. Movements of the antennas are controlled by muscles, which again are controlled by nerve impulses. The antennas are also use for food collection as the animals can create a water current that directs food particles towards the mouth. Thus, the ability to control the antennas is essential for the growth and survival of a Daphnia. However, as some environmental pollutants such as pesticides are designed to deteriorate the nervous system of insects they can likely also affect nervous system among crustaceans. Since swimming direction and speed are regulated by density and type of particles in the water, it is apparent that any alien particles is disturbing. Such particles could be micro plastics that today is known to be present almost everywhere. The implication of pollutant and micro plastic can be studied through rather simple experimental setups using cultured Daphnia species and a micro swimming pool. Various pollutants and micro plastic are commercial available and can be used safely in the laboratory. Daphnia species are easy to culture in laboratory cultures and because of their ability to perform parthenogenetic reproduction it is possible to have establish unique clonal populations, which is ideal for running physiological and behavioral studies. Furthermore, Daphnia tolerates handling quite well and are almost transparent which makes it possible to observe activities of organs and other structures inside live specimen. The detection methods will depend on the specific purpose and could include image and video documentation, microscopy, and visual observations. As part of the project you´ll learn how to establish and grow your own cultures of Daphnia and the microalgae they will feed on.
|Anvendte metoder:||Lab experiments, LC50, growth, behaviour, swimming speed, microscopy|
|Keywords:||Daphnia, Toxic compounds, Micro plastic, Foodweb|
|Vejleder(e):||Kirsten S. Christoffersen|