The Chemistry of a Bloom: What Water Tests Reveal About Toxic Algae

Algal blooms are more than just unsightly green scums on the surface of lakes, rivers, and coastal waters—they are complex chemical events that can have profound environmental and public health consequences. Understanding the chemistry behind these blooms is key to early detection, effective monitoring, and mitigating their impacts. Fortunately, water testing technologies are revealing powerful insights into what’s really happening below the surface. 

Water Tests That Tell the Story 

Modern water testing allows scientists and community monitors alike to track the chemical shifts associated with blooms in near-real time. Here's what these tests typically measure: 

• Chlorophyll: This pigment is a proxy for algal biomass. High chlorophyll levels often indicate bloom presence or intensity. 

• Phycocyanin: A pigment unique to cyanobacteria. Measuring this pigment helps with indicating potentially toxic blooms. 

• Nutrients (Nitrogen & Phosphorus): Excess nutrients act as bloom fuel. Testing their concentration can help identify pollution sources and bloom triggers. 

• Dissolved Oxygen (DO): Blooms can deplete oxygen levels when they decay, leading to fish kills. DO sensors track this critical parameter. 

• pH and Temperature: These influence algal growth and can signal bloom-prone conditions. 

• Toxin Testing: Lab analysis or rapid test kits can detect and quantify specific algal toxins in the water. 

Turner Designs’ fluorometers, for example, allow for in-field detection of chlorophyll and phycocyanin using fluorescence technology—providing a fast, reliable picture of bloom activity without needing to send samples off to a lab. 

Real-World Impacts of Water Chemistry Data 

The chemical profile of a bloom helps guide public health responses, such as issuing swimming advisories or closing drinking water intakes. In 2014, for instance, elevated microcystin levels in Lake Erie left half a million people in Toledo, Ohio without safe drinking water for days. Since then, real-time monitoring of bloom chemistry has become a priority for water utilities across the country. 

In aquaculture, early detection of toxin-producing algae helps farmers act before stock losses occur. Coastal managers use water chemistry to predict harmful algal blooms (HABs) and protect fisheries and tourism. 

Looking Ahead: Chemistry as a Tool for Resilience 

As climate change and nutrient pollution continue to increase the frequency of blooms, the chemistry of the water will remain our most vital diagnostic tool. With more accessible, high-resolution water testing tools, communities, scientists, and water managers can work together to respond faster, reduce risks, and build more resilient ecosystems. 

Conclusion:  Understanding the chemistry of algal blooms transforms them from mysterious green invaders into measurable, manageable events. Through ongoing innovation in water quality testing—like Turner Designs' fluorescence-based sensors—we’re not just observing the problem, we’re uncovering solutions in real-time. 

 Case Study: How a Coastal Community Tackled a Toxic Bloom Crisis Through Real-Time Water Monitoring 

Background: The Crisis in Indian River Lagoon, Florida 

In the summer of 2016, Florida’s Indian River Lagoon—one of the most biodiverse estuaries in North America—experienced a severe harmful algal bloom (HAB) event. Fueled by warm temperatures and nutrient-rich runoff from agriculture and urban areas, the bloom was primarily composed of Microcystis aeruginosa, a cyanobacterium capable of producing potent liver toxins. 

The bloom clouded the water, reduced oxygen levels, and led to a wave of fish kills. Local tourism suffered, residents expressed concern over water safety, and shellfish harvesting was temporarily suspended. This wasn’t just an environmental issue—it became an economic and public health emergency. 

The Response: Empowering Local Stewards with Fluorescence-Based Tools 

In response to this crisis, the Indian River Lagoon National Estuary Program partnered with community groups, universities, and technology providers to establish a real-time water monitoring network. A key part of this effort involved deploying Turner Designs' submersible fluorometers to measure: 

• Chlorophyll (as an indicator of total algal biomass) 

• Phycocyanin (to detect cyanobacteria specifically) 

• Dissolved oxygen and temperature 

These compact sensors allowed researchers and even trained volunteers to monitor water quality at multiple points along the lagoon. By tracking the chemistry of the bloom in real time, they were able to: 

• Map bloom progression 

• Identify hotspots of toxin production 

• Alert the public and local officials more quickly 

Results: Community Engagement and Faster Decision-Making 

The data collected helped local decision-makers implement early warnings and public advisories, preventing potential health exposures. Perhaps more importantly, the project empowered community members to become active participants in environmental protection. 

Local schools and citizen science programs incorporated the water sensors into educational fieldwork, creating a new generation of stewards. Residents who once felt helpless during previous bloom events now had tools—and agency—to take action. 

Long-Term Impact: Building Resilience Through Chemistry 

Thanks to this collaborative, tech-enabled approach, Indian River Lagoon now has a more robust HAB response system. The success of the project also inspired similar community-driven monitoring initiatives across other Florida estuaries. 

This case illustrates a key truth: real-time water chemistry isn’t just data—it’s decision power. With the right tools, partnerships, and local involvement, communities can better respond to the growing threat of harmful algal blooms. 

Conclusion:  The Indian River Lagoon case highlights how fluorescence technology, accessible monitoring tools, and local engagement can transform environmental crises into opportunities for innovation and resilience. Turner Designs is proud to support this kind of proactive, community-led response—one sensor, one steward, and one data point at a time.