How can more abundant plant life ever be a bad thing? Well, have you ever heard of a red tide? With algal blooms, it can be toxic.
An algal bloom, or water bloom, is the abundance of algal cells in the water, one of which on its own is usually not visible to the naked eye. But they can reproduce quickly and with enough of them, it's not hard to miss. Their color is brown, green, red, or a blue-ish tone and can appear as a cloud in water, floating scum, stringy mats, or underwater clumps of slime. Algal blooms occur from nutrient density- mainly nitrogen and phosphorous. This arrives into bodies of water from human sources, such as:
- Agriculture: Probably the highest source of nitrogen and phosphorous concentration comes from livestock manure, and fertilizers for crops via groundwater access.
- Stormwater: When it rains in urban areas, the water exits through waterways and drainage, but it first takes with it all the pollution, including phosphorous and nitrogen, from sidewalks, streets, rooftops, and parking lots.
- Wastewater: Septic systems and sewage treatment plants do not always work up to code and thus, sometimes do not filter the nutrients out completely before it reaches our water environments.
- Domestic Products: Yard and garden fertilizers, pet wastes, and certain soaps and detergents that contain nitrogen and phosphorous, can all contribute to nutrient density that leads to algal bloom, depending on landscaping and the amount of hard surfaces.
Once these nutrients access water ecosystems, combined with full sunlight and slow-moving water, it's a matter of time before the algae blooms. And once this happens, some can release harmful toxins into the water or harm the environment in other ways.
With enough density of a floating type of bloom, it can block the sunlight from accessing the aquatic plants to be able to produce photosynthesis. So, not having enough phytoplankton due to algal blooms then starves the zooplankton out and this then disrupts the entire food chain that relies on each trophic level to survive. Algal blooms also absorb the oxygen from the water to sustain itself, thereby depleting the aquatic beings their own share and suffocating them. Some freshwater algal blooms are formed by cyanobacteria and produce toxins called, microcystins that can be extremely harmful to animals, including humans and their pets. Humans are harmed by this type of algal bloom typically from their drinking source which can create a change in the taste and odor of the drinking water, if not health issues like neurological disorders, as well. Cyanobacteria is naturally found in water environments, but the amount is so minute that heterotrophic bacteria found there can break down the toxins before it harms anything or anyone. However, the level of reproducing algal blooms is so great that the bacteria cannot keep up with the rate of toxins and so it falls behind.
Not only is algal bloom harmful to its environment as well as sometimes being toxic to humans and their pets through their drinking water sources, but the exposure can also cause skin irritation by way of recreation like swimming, boating, water skiing, and diving. Also, inhaling it from the water spray can be toxic and have led to death in both humans and dogs from exposure. It also affects the aesthetics and local economy from the look of algal blooms and the terrible smell that is released once the cells begin to die, as well as the income generate from fishing jobs.
Unfortunately, fighting cyanobacterial blooms and other kinds of algal blooms, is also fighting climate change since global warming increases the temperatures of water and changes the salinity in the favor of algae. But using chemical to kill off the blooms can be harmful to the beings living within the water and in some cases, increase the toxicity of cyanobacteria. Thus, the best methods are preventative measures, instead. By targeting the sources of nutrient discharge from point (directly fed through drains and pipes that originate from urban and industrial sources) and nonpoint (indirectly fed through sources like groundwater and streams), this can negate development of harmful algal blooms. A alternative method for smaller water environments, however, like ponds and small lakes, are utilizing devices that create water movement, such as air bubbles. The more current of water, the inability of bacterial development. Another one is by emitting ultrasonic frequencies to control algae in lakes, reservoirs, and estuaries. Though this option seems safe to the environment because it is chemical-free, it would not be a great choice in marine areas where some mammals use ultrasonic waves with echolocation. The effects have also not been fully tested in freshwater environments, especially in terms of longevity.
Though the treatments of chemicals, movement and aeration devices, and ultrasonic frequencies are great quick-fixes to control and mitigate algal blooms, the safest and most innocuous treatment is by far stopping the cause of the nutrients from the horse's mouth. This treatment option does mean it takes longer to see results which can then cause more damage environmentally, economically, and locally; it is the most effective with the least side-effects. This of course is a preventative, and not treating the existing algal blooms, albeit by depleting their nutrient sources. However, a chemistry professor at Western Michigan University is working with a team to harvest the existing algal blooms with "turf scrubbers" (small-scale algae processing systems) and then utilize it as an alternative energy; a biofuel resource. So, while the nutrients are getting depleted from point and nonpoint sources to prevent future blooms, the algae can be collected as an alternative fuel that will also fight climate change which in turn, further helps heal our waters!