Satellite view of algal blooms in Lake Erie, a source of drinking water for over 10 million Americans. Source: NASA

Environmental Technology magazine notes that the difficulty in predicting how algae blooms will develop lies in their variform nature. With a multitude of different blooms affecting different parts of the coastline and interior bodies of water — from blue-green cyanobacteria to red dinoflagellates Karenia brevis — algal blooms are tricky to pin down and even more difficult to anticipate. However, through a variety of monitoring techniques and modelling programs, scientists are able to predict their movements to some degree.

Blue-green epidemic
Found all over the world, blue-green algae is not consumed by any other organism and as such, can simply grow and grow if left unchecked. As well as being present in the UK and Australia, it’s found in bodies of water in all 50 states of the US, most notably in Lake Erie, which is a source of drinking water for over 10 million Americans. It’s directly affected by agricultural runoff, which carries phosphorous into rivers and streams, which in turn take it to lakes, reservoirs and oceans.

In order to predict blue-green algae blooms, high-resolution monitoring of rivers several times a day is essential to maintain a comprehensive picture of how much phosphorous is entering Lake Erie. Shorter-term predictions can also be compiled using satellite imagery and wind forecasts to anticipate where blooms will appear within the lake itself.

Red tides
When Karenia brevis are broken down by the crashing of the waves, they die and release brevetoxins, a type of neurotoxin hazardous to human health. The brevetoxins become airborne and infiltrate lungs and eyes, causing difficulty in breathing and irritation around the eyes. For those suffering from asthma or other respiratory conditions, the effects can be even more serious.

The problem is particularly troublesome on Florida’s coastline and, in 2017, the state’s Mote Marine Laboratory and Aquarium developed HABScope, a program to analyze and predict the blooming of red tides. After collecting samples of seawater three times a day off the coastline, the researchers record a short video of how the algae behave under a microscope. They then feed this data into an AI modelling program to determine where it is most likely to surface next.

Contaminated seafood
Rod-shaped algae named Pseudo-nitzschia are commonly found in warm seawater and can be devastating if consumed via shellfish. The toxic acid secreted by the algae can induce memory loss and brain damage, even resulting in death in extreme cases. It regularly affects marine life off the western coast of the US (and by extension, the fisheries which operate there) every year.

In order to minimize the detrimental effects of this harmful algae, scientists at Scripps Research Institute have developed a public forecast program called C-HARM. This uses a computer model which assimilates information about ocean temperature and salinity as well as chlorophyll patterns to predict where blooms are likely to occur. At present, collecting information about these waters is a time-consuming process, but the advent of drones is likely to make things easier in the near future.

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