Harmful blooms are caused by algae, simple aquatic plants that range from microscopic single-celled protists to colonial filamentous microalgae to large seaweeds, forming the base of food webs they are vitally important to marine and freshwater ecosystems.
Toxic algae outbreaks can vary a lot but imagine chemical looking stinky, slime floating on the surface of a river lake, or ocean you get a general idea. The most important thing to know is that these outbreaks can be dangerous getting in and sometimes even near water where there’s a toxic algae bloom, it can make people and pets experience symptoms such as nausea, sore throat, rashes, vomiting, diarrhea, flu-like symptoms, and even liver damage.
Algal blooms can deplete oxygen levels, creating a dead zone where nothing can grow which sets up a chain reaction that’s devastating for anything living in or near the water but the real problem is the toxin that some types of blooms can create which are poisonous and even deadly for fish, wildlife as well humans.
A small percentage of blooms are toxic but those are the ones that can contaminate the local drinking water supply and seafood because they’re becoming more widespread scientists are wondering why that’s the case but we do know that toxic algae blooms are usually caused by agricultural pollution manure and fertilizer that runs off farms, changes in the environment from climate change like warmer water temperatures and in some areas heavier rainfall are probably triggering blooms to start earlier and last longer.
One major requirement for algal toxic blooms is the overabundance of nutrients nitrogen and phosphorus and water nutrient replete waters may come from rainfall upwelling, areas urban runoff and wastewater outflows when nutrients increase the right combination of water temperature, sunlight, salinity and water circulation and movement can trigger an algal bloom.
Although many different species of algae can form blooms not all algal blooms are harmful and not all require dense bloom concentrations to cause adverse impacts. Some are the toxin producers which produce highly potent toxins or toxic aerosols that can sicken or kill animals and humans directly exposed or through ingestion of other organisms contaminated with the toxins.
The second group is high biomass producers which are non-toxic but after reaching dense concentrations it can create dead zones which can block the sunlight, inflict physical injury, and lower the level of oxygen in the water, leading to mass mortalities of various wildlife.
Some have characteristics of both groups and can change an ecosystem dramatically by dominating and out-competing the natural phytoplankton population and altering the food web dynamics, which has severe economic and cultural implications resulting from substantial losses, especially for the fisheries sectors and coastal communities that are dependent on seafood harvesting and tourism.
Eutrophication or nutrient pollution due to enhanced anthropogenic activities from farming, aquaculture and urbanization, transport of organisms by ship ballast waters, and more recently the practice of overfishing have all been implicated as possible reasons for having this event more and more often.
When you notice a bloom in your area report it to local officials if you. Keep pets and children away from the algae, rinse off with clean water if touched by algae, and also avoid consumption of contaminated seafood.
Erzsebet Frey (Eli Frey) is an ecologist and online entrepreneur with a Master of Science in Ecology from the University of Belgrade. Originally from Serbia, she has lived in Sri Lanka since 2017. Eli has worked internationally in countries like Oman, Brazil, Germany, and Sri Lanka. In 2018, she expanded into SEO and blogging, completing courses from UC Davis and Edinburgh. Eli has founded multiple websites focused on biology, ecology, environmental science, sustainable and simple living, and outdoor activities. She enjoys creating nature and simple living videos on YouTube and participates in speleology, diving, and hiking.