What Are Toxic Algal Blooms? Stony Brook University's Christopher Gobler Explains


Christopher Gobler

Dr. Christopher Gobler and his lab at the School of Marine and Atmospheric Sciences (SOMAS) at Stony Brook University are engaged in pioneering research investigating the causes and effects of harmful algal blooms in aquatic ecosystems, including the terrible toxic algae outbreak in Florida this summer. His lab also focuses on how human-caused activities such as nutrient pollution, climate change and the over-harvesting of fisheries alter the ecological functioning of coastal ecosystems. If his name rings a bell, that's because we have interviewed Chris in the past. Earlier this year, the Environmental Protection Agency recognized Chris with their Environmental Champion Award. In 2014, Chris was appointed the Associate Dean of Research at SOMAS and in 2015 he was named co-Director of the New York State Center for Clean Water Technology.

This year, toxic algae blooms have sprung up from coast to coast. What are toxic algae and what threat does it pose to people and ecosystems?

While algae are the base of aquatic food webs, some species and types synthesize biotoxins that can be a threat to human health, animal health or whole ecosystems. In marine ecosystems, toxins can enter food webs and thus contaminate seafood. In freshwater ecosystems such as lakes, ponds and rivers, blooms of toxic blue-green algae can contaminate drinking water or even water that is used for the irrigation of crops, as occurred in Utah this summer.

In the terrible Florida toxic algae outbreak, all the focus has been on phosphorus pollution with little going to nitrogen. What did your team find about the role of nitrogen pollution in that Florida outbreak, and what implications does nitrogen pollution have on algal blooms in general?

The traditional dogma in terms of the nutrients and harmful algal blooms (HABs) is that phosphorus controls blooms in freshwater systems, and nitrogen controls blooms in marine systems. However, as time marches on, many exceptions to these rules have been uncovered. Regarding the events in Florida: yes, phosphorus has been the major focus. However, preliminary research by our lab suggests that nitrogen may have been controlling the intensity of that event. This finding supports the growing body of evidence that controlling nitrogen and phosphorus will be needed to mitigate the occurrence of HABs in freshwater and marine ecosystems.

Where does nitrogen pollution rank among our environmental challenges?

Globally, scientists have identified nitrogen pollution as one of the major national and global environmental problems we face today. In the 20th century, people perfected the ability to 'fix nitrogen', or convert gaseous nitrogen, which is 80 percent of our atmosphere, to fertilizer. While this has led to an explosion of food production, it has also led to the scenario where people are adding more nitrogen to the planet than nature. During the past several decades, the incidence of HABs has increased significantly. There is a scientific consensus that this is partly due to the overloading of nitrogen into coastal waters.

How does our food system factor in to this national and global problem?

The largest source of nitrogen to coastal ecosystems globally is farm fertilizer primarily due to the inefficient use of synthetic nitrogen fertilizer. In other regions, concentrated animal feeding operations [CAFOs, or factory farms] represent a strong local source of nitrogen that has been shown to promote and stimulate HABs.

What role is there for policymakers to play in tackling nitrogen pollution from the agricultural sector? Are there practical solutions in place that reduce the problem of nitrogen pollution and algal blooms?

When it comes to HABs, solutions are often site-specific. That being said, the most intense blue-green algae blooms across the US in Florida, the Great Lakes, Utah, California and elsewhere are associated with agricultural fertilizers. In each of these cases, it makes sense for policy makers to carefully examine agricultural practices in these regions and nationally to protect surface waters and human health against toxic HABs. In other, more urbanized regions, wastewater is the major source of nitrogen to coastal waters. Technological advances are making it possible to sharply reduce nitrogen from these sources.

What role is there for consumers to play?

For consumers, I think everyone can recognize they have a personal nitrogen and phosphorus footprint that is influenced by how much driving they dohow much and how often they use synthetic fertilizers and how much meat they consume.


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