Why people monitor for algae?The amount and type of algae can tell you a lot about the health of that system, but first let's cover what we're referring to as algae, in simple terms algae are photosynthetic organisms like plants. We can separate out the macroalgae, such as the red brown and green algae sometimes referred to as seaweeds.
Let's instead focus on the micro algae or single-celled algae, prokaryotes like blue-green algae lack a nucleus, this technically makes them photosynthetic bacteria but they are still important to this discussion. There are also the eukaryotes like those that cause red and brown tides.
One thing all of these microalgae have in common is that you can find them in both freshwater and marine environments.
One major reason to monitor for algae is aquatic ecology research, this includes primary productivity like photosynthesis, system health and dynamics and an interest in the types and abundance of algae in a system.
But the big reason to monitor for algae these days is source water protection and concerns over drinking water safety.
Most countries are dealing with harmful algal blooms, these can range from cyanobacteria to red tides and cause severe impacts on residents and local wildlife, so there is a need for algae monitoring.
So why do we monitor for algae?
Scientists might be interested in how a body of water switches over from what we sometimes call healthy algae, like diatoms to unhealthy algae like the blue greens.
A treatment plant operator or drinking water manager would be more concerned if the product they're delivering is clean and safe for consumption and of course public beach goers want to know if it's safe to swim or fish in the water.
Overall, the important thing is to realize what changes are happening and with that information you can take better decisions in order to avoid or minimize the impact.