A Lake’S PECKING ORDER

Primary producers are the lowest rung on the pecking order. Algae (phytoplankton) and other aquatic plants, fed by nutrients, comprise the bottom of the food chain. The nutrients that feed them result from fertilizer, animal waste, and soil erosion. Nutrients are good, but only in limited amounts. Excess nutrients often cause algae blooms and excessive weed growth.

Primary consumers are the herbivores that munch on algae. Zooplankton eat the algae. A couple of common types in our lakes are cyclops (this zooplankton has a single eye spot) and daphnia (also called water fleas).

Small fish that make a big impact are called secondary consumers. These planktivores, like pumpkinseed and yellow perch, eat zooplankton. These small fish are stuck in the middle of the food chain, a ecting and being a ected by the levels above and below them. Too many small fish in a lake can substantially reduce zooplankton populations which can allow the algal population to increase.

Tertiary consumers are the dominating trophy fish. The top of the food chain is dominated by piscivores like northern pike and largemouth bass... fish that eat other fish! They rely on the lower rungs of the food chain, but if the pisciv- ore population is too high, the population of smaller fish will shrink. This allows for more zooplankton, which ultimately reduces algae populations.

Every food chain level is important for a balanced and healthy lake habitat. So where do you fit in? Help reduce the chance for algae blooms by avoiding harmful or excessive fertilizers or lawn treatments. Another easy way is by signing up for the Lilly Center’s monthly e-newsletter. Staying informed about lakes and their inhabitants is a great way to protect both. Sign up at lakes.grace.edu/get-involved!