What is it?
You’ve probably heard of the term “red tide” or seen images of eerie green lakes or massive fish kills on the news. These are often caused by harmful algal blooms, commonly known as HABs. But what exactly are they?
Harmful algal blooms occur when algae, which are naturally present in our waters, begin to grow out of control. While not all algae are harmful, certain types can produce potent toxins or deplete the water of oxygen as they die off. This creates dangerous conditions for fish, shellfish, birds, marine mammals, and even people.
These blooms can happen in both saltwater and freshwater environments. They are often driven by a combination of factors, including warm temperatures, stagnant water, and most importantly, an excess of nutrients like nitrogen and phosphorus. These nutrients often come from fertilizers used in agriculture and landscaping, as well as untreated sewage and urban runoff. As our climate warms and storms become more intense, conditions for HABs are becoming more favorable and frequent around the world, especially in places like Florida.
Why it matters.
The consequences of harmful algal blooms go far beyond unsightly water and dead fish. These blooms can have major impacts on:
- Human health: toxins from HABs can contaminate drinking water and seafood, causing illnesses such as respiratory issues, skin rashes, gastrointestinal symptoms, and in extreme cases, liver damage, or neurological effects.
- Ecosystems: HABs can suffocate aquatic life by depleting oxygen levels in the water, leading to massive die-offs of fish and invertebrates. This disrupts entire food webs and diminishes biodiversity.
- Local economies: tourism, fisheries, and water-based recreation can suffer significant losses due to closed beaches, canceled fishing seasons, and public health warnings.
- Water quality: HABs can degrade the quality of lakes, rivers, and coastal waters, making them unsafe for people and wildlife.
Yet, even if you do not live in a coastal area, HABs can and do have an impact. As blooms become more intense or prolonged, the impacts of HABs spread much further inland.
What you can do!
Harmful algal blooms might seem like a big, complex issue, but individual action really can add up to remedy these negative anthropogenic blooms. Here are a few easy ways to help prevent harmful algal blooms:
- Use fertilizer wisely (or not at all): when using fertilizers, apply them sparingly and follow label instructions. Try switching to organic options or compost to reduce runoff.
- Support green infrastructure: rain gardens, bioswales, vegetated buffers, and permeable pavement help absorb stormwater and filter out pollutants before they reach waterways.
- Dispose of waste properly: never dump pet waste, oils, chemicals, or medications into storm drains or waterways. These can contribute to nutrient overloading and water contamination.
- Plant native vegetation: native plants require less fertilizer and water, and they help stabilize soils and reduce runoff.
- Get involved locally: join or support local watershed groups, advocate for water quality protections, and participate in community cleanups.
- Stay informed and spread the word: understanding the problem is the first step. Share what you learn with others and encourage your community to take action!
It’s important to understand that you likely won’t see results overnight. Ecosystems take time to heal, and the effects of preventative action may not be immediately visible. But know this: your efforts matter. By taking action, however small, you are helping to protect waterways, wildlife, and communities from the harmful effects of algal blooms.
Every yard that goes fertilizer-free, every voice that supports cleaner water policies, and every community that invests in green infrastructure helps shift the tide. The fight against harmful algal blooms starts with awareness and continues with action!
Information from Florida Health, NOAA, UF IFAS, Florida Sea Grant, and Florida FWC. Cover image by Zachary Haslick/Aerial Associate Photography/NOAA.