Harmful Algae & Red Tides

What are ocean scientists doing to prevent HABs?

At the moment, one useful approach in the management toolbox is to continuously monitor water conditions. For example, a new instrument called the Imaging FlowCytoBot (IFCB) can be deployed in waters where HABs are likely to occur. The IFCB is an underwater microscope that takes hundreds of thousands of photos of algae daily, identifies them, and reports the numbers of each species spotted in the images. When algae known to be harmful become abundant, researchers notify nearby managers and industries, so they can close beaches for shellfish harvesting or take other actions to mitigate harm.

Beyond monitoring, researchers are working to predict when and where HABs are likely to occur. To so do, they first need to identify the environmental triggers involved. Warm water temperatures play a role, and climate change may be contributing to recent increases in HABs, but many other factors are involved as well. Some blooms tend to occur in areas such as the mouth of the Mississippi River in the Gulf of Mexico, the end point where runoff has accumulated from upstream farms and overfertilized lawns. Such runoff has high levels of otherwise limiting nutrients that are known to promote algal blooms.

As there are many other possible contributing factors, scientists are busy investigating which specific sets of conditions lead to these destructive blooms of algae. As they collect more data and incorporate those data into their models, they are better able to forecast future outbreaks.

Scientists are also devising methods to remove toxins and toxic algae when HABs do occur. This is quite a challenging task, as many other beneficial organisms co-occur with HABs, and many researchers worry that the treatment may be more harmful than the problem.  Applying natural mineral clay, an environmentally benign approach used in other countries, is currently under investigation as a potential solution in U.S. coastal waters. When a fine spray of clay particles is spread over a HAB, the clay particles bond together, capturing additional particles, including HAB cells, as they sink to bottom sediments. In addition, clay can remove 70% or more of some HAB toxins.

Researchers are also investigating how toxins move through the food chain, so they can better understand how they harm animals and people. And they are working with Indigenous communities in the Arctic to address newly discovered HAB threats occurring there. Massive blooms of dangerous algae are a recent occurrence in the historically too-cold waters of the Arctic Ocean. High levels of potentially paralyzing toxins have been found in marine mammals that are part of the subsistence diet for people living in these regions, presenting a new problem they haven’t previously had to address.