As mentioned earlier when discussing the habitat of D. pulex, this organism plays a very distinct role in the aquatic ecosystem. First, they provide food for a large amount of fish in the ecosystem. In addition, they also play a very important role in helping to maintain water quality by feeding on algae and bacteria. In the food web, Daphnia would usually be considered primary consumers.

Next, D. pulex are also a host for many parasites. There have been six determined species of bacterial parasites which invade the Daphnia population. Four of them affect the organism’s hemolymph, while the other two have been found to affect the fat cells and eggs. If that parasite has infected the hemolymph, the Daphnia might appear to have a tint of milky white, brown, pink, or yellow.


D. pulex are also hosts to many fungal parasites as well; however, there isn’t much known about them due to their differences in appearance and varying effects on their host. Also, fungal parasites among Daphnia are difficult to work with in the lab. What scientists do know, though, is that fungal parasitic infections in Daphnia are actually some of the most destructive among the population and often kill the host quickly.


D. pulex also interact with humans in a way that they provide many uses for them. First off, although Daphnia do not provide a direct food source for humans, they do, however, provide the fish, in which humans are catching, with food. Fishing is a huge industry today and without the food source of Daphnia, this industry may not be as sustainable as it is today due to lack of fish population. Also, D. pulex are commonly used in the lab by scientists because they are small, relatively inexpensive, and easy to culture since they are so versatile with their habitats. Next, because Daphnia are transparent, it makes it easy to study internal structures of the organism such as the heart beat and the digestive system. Lastly, Daphnia are used in aquariums to help cut down on algae and levels of debris.

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