Lentic and Lotic Systems

There are 2 types of inland freshwater ecosystems: Lentic and Lotic. 

LENTIC SYSTEMS

Lentic systems, coming from the Latin term Lentus, means the aquatic system is moving very slowly, so slowly that the water appears to be motionless or nearly so. If you’ve ever seen a pond, lake, or wetland, you’ve witnessed a lentic system! Typically, there is a lower species diversity here as well, but that doesn’t mean they aren’t present! You might see an aquatic sow bug (Isopoda, Asellidae) or a crane fly (Tipulidae). Take a look in your local pond and see what critters are moving about! 

Hillman Marsh. Photo by Shayenna Nolan

LOTIC SYSTEMS

Lotic systems, coming from Lotus, are much faster flowing and you can visibly see the running water. As mentioned before in one of our previous posts, fast moving waters which can be riffles can scour away at the surrounding landscape, much more as compared to lentic systems.  Lotic systems include rivers, streams and creeks and typically have a higher species diversity. However, critters that like here must be able to hold on tight as the forces of the water is constantly acting upon them. Some invertebrates have the ability to cement themselves onto a rock as to not be swept downriver, like black flies (Simuliidae), whereas others use it to their advantage by creating a net, catching any food which is swept up in the current like net-spinning caddisflies (Hydropsychidae).  

What about oceans you ask? They actually aren’t considered lentic nor lotic! This is because although the currents are moving, they aren’t moving in one direction as it would be in rivers and streams.  

Long Marsh Drain. Photo by Shayenna Nolan