--- title: "Blue-Green Algae Sensors & Monitoring | Aethair" description: "Blue-green algae is the common name for cyanobacteria, photosynthetic microorganisms that behave like algae and can form dense, sometimes toxic blooms in…" url: https://aethair.io/parameters/bga/ --- Measurements · Water Quality # Blue-Green Algae Also known as cyanobacteria, phycocyanin, bga pc Blue-green algae (cyanobacteria) pigment fluorescence (phycocyanin/phycoerythrin). [Schedule a call](https://calendly.com/d/ctdd-mkr-v9v/aethair-demo-website) [Configure Blue-Green Algae Monitoring](https://aethair.io/build/?params=bga) At a glance µg/L Water Quality 1 way to measure it - **Thiamis** 4 external instruments What it is ## What is blue-green algae? Blue-green algae is the common name for cyanobacteria, photosynthetic microorganisms that behave like algae and can form dense, sometimes toxic blooms in nutrient-rich water. They are monitored in-situ by detecting their accessory pigments (phycocyanin in freshwater cyanobacteria and phycoerythrin in some marine and brackish species), with the result reported as an estimated concentration in micrograms per liter. Unlike the general chlorophyll signal, which reflects all algae, the blue-green algae channel specifically targets cyanobacteria, which matters because they are the group most associated with harmful algal blooms (HABs) and the production of toxins. Continuous blue-green algae monitoring is the practical early-warning system for bloom risk in drinking-water reservoirs, recreational lakes, and coastal waters. Because cyanobacterial toxins pose a direct threat to people and animals, blue-green algae is a high-priority parameter wherever water is drunk or used for recreation. ### Health and operational effects Cyanobacteria can produce potent toxins that affect the liver, nervous system, and skin, posing a risk to drinking-water supplies, to swimmers, and to animals that drink from affected water. Livestock and pet deaths are a recurring outcome of severe blooms. Even without toxins, dense cyanobacterial blooms cause taste and odor problems, shade out other life, and, like any algal bloom, strip oxygen from the water when they die and decompose, threatening fish. Blooms are favored by warm, calm, nutrient-rich conditions, so they are a growing symptom of eutrophication and warming waters. How it is measured ## How Blue-Green Algae Is Measured Blue-green algae is measured by fluorescence, targeting the pigments unique to cyanobacteria: the sensor excites phycocyanin, or phycoerythrin, with light of a specific wavelength and measures the fluorescence re-emitted, which is proportional to the amount of cyanobacterial pigment and hence to the cyanobacteria present. It is one channel of a multiparameter sonde connected to a Thiamis gateway, distinct from the chlorophyll channel so that cyanobacteria can be picked out from total algae. As an optical sensor it is vulnerable to biofouling and to interference on the window, so a wiper, regular cleaning, and calibration checks are needed to keep the fluorescence estimate reliable over a deployment. An instrument on Thiamis 4 A third-party instrument connected to a Thiamis gateway, reporting into the same Environet account. ### Placing blue-green algae sensors Blue-green algae is measured in-situ by the sonde, and placement is critical because many cyanobacteria regulate their buoyancy and accumulate at the surface and along downwind shorelines, exactly where people and animals encounter them. Siting the sensor at a representative depth, or profiling, and monitoring near intakes and bathing areas captures the risk where it matters. Because blooms can intensify within days and drift with the wind, continuous logging with alarms gives the early warning that periodic sampling cannot. A wiper and routine cleaning keep the optical window clear so the pigment signal is not distorted by fouling. ### Every device and option that measures Blue-Green Algae 4 | Device / option | Type | Base platform | Measures | | - | - | - | - | | [YSI](https://aethair.io/sensors/ysi-water-quality-sondes/) · EXO1, EXO1S, EXO2… | Water Quality Sondes | Thiamis | Blue-Green Algae [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Chloride](https://aethair.io/parameters/chloride/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Conductivity](https://aethair.io/parameters/conductivity/) [Dissolved Oxygen](https://aethair.io/parameters/do/) | | [In-Situ](https://aethair.io/sensors/in-situ-water-quality-sondes/) · Level TROLL 300, Level TROLL 400, Level TROLL 500… | Water Quality Sondes | Thiamis | Blue-Green Algae [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Chloride](https://aethair.io/parameters/chloride/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Conductivity](https://aethair.io/parameters/conductivity/) [Density](https://aethair.io/parameters/density/) | | [Spectra Scientific](https://aethair.io/sensors/spectra-scientific-water-quality-sondes/) · Spectra Litmus 6, Spectra Litmus 4 | Water Quality Sondes | Thiamis | Blue-Green Algae [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Chloride](https://aethair.io/parameters/chloride/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Conductivity](https://aethair.io/parameters/conductivity/) [Density](https://aethair.io/parameters/density/) | | [YSI](https://aethair.io/sensors/ysi-water-quality-sondes/) · 6600 V2, 6600EDS V2, 6920 V2… | Water Quality Sondes | Thiamis | Blue-Green Algae [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Chloride](https://aethair.io/parameters/chloride/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Conductivity](https://aethair.io/parameters/conductivity/) [Dissolved Oxygen](https://aethair.io/parameters/do/) | [Configure Blue-Green Algae Monitoring](https://aethair.io/build/?params=bga) Where it is monitored ## Solutions That Monitor Blue-Green Algae Each one links to the solution page showing what that industry measures it for. ### [Aquaculture & Fish Farming](https://aethair.io/solutions/aquaculture/) Often added Dissolved oxygen, temperature, and ammonia control ### [Water Quality Monitoring](https://aethair.io/solutions/water-quality/) Often added Rivers, lakes, drinking water, and stormwater Related ## More in Water Quality [Water Temperature](https://aethair.io/parameters/water_temperature/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [Turbidity](https://aethair.io/parameters/turbidity/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) Questions ## Blue-Green Algae FAQ Why monitor blue-green algae separately from chlorophyll? Chlorophyll measures all algae, while the blue-green algae channel specifically targets the pigments of cyanobacteria, the group responsible for most harmful, toxin-producing blooms. Seeing the two together shows how much of a bloom is potentially toxic, which a general chlorophyll reading alone cannot reveal. Are blue-green algae dangerous? They can be. Cyanobacteria can produce toxins affecting the liver, nervous system, and skin, posing risks to drinking water, bathers, and animals, and severe blooms have killed livestock and pets. Even non-toxic blooms cause taste, odor, and oxygen problems, so early detection matters. What conditions cause blue-green algae blooms? Warm, calm, nutrient-rich water, especially where nitrate and phosphate enrichment coincides with sunlight and low mixing. Because these conditions are becoming more common with warming and eutrophication, cyanobacterial blooms are an increasing concern, which is why continuous early-warning monitoring is useful. How do I monitor blue-green algae? Deploy a multiparameter sonde with a phycocyanin, or phycoerythrin, fluorescence sensor and a wiper, connected to a Thiamis gateway, logging continuously with alarms on rising values. Use the configurator to pair a logger with a sonde covering blue-green algae alongside chlorophyll, dissolved oxygen, temperature, and the nutrient channels.