Experts on Camera

Dr. Silvia Secchi: Harmful algal blooms

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Harmful algal blooms—overgrowths of algae that can seriously harm people and pets, kill fish and other wildlife, and damage ecosystems—are a worsening problem in lakes, ponds, and along coastlines nationwide.

On Wednesday, June 15th, 2022, SciLine interviewed: Dr. Silvia Secchi, a professor of geographical and sustainability sciences at the University of Iowa. See the footage and transcript from the interview below, or select ‘Contents’ on the left to skip to specific questions.

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SILVIA SECCHI: My name is Silvia Secchi, and I am a professor in the department of geographical and sustainability sciences at the University of Iowa. And broadly speaking, I study the interactions between humans and the environment. Specifically, I study the environmental impacts of agriculture and feedback effects. So, you know, I live in Iowa, so we have a lot of agriculture. And so I study how our activities affect water quality and the climate and then how this feedbacks into human activities, so for example, how we deal with the pollution in our water and the climate change that is caused by human activities.

Interview with SciLine

What are harmful algal blooms?


SILVIA SECCHI: These are essentially blooms of algae and cyanobacteria that cause impacts on ecosystems and human health. And so we think generally about toxic effects, but we could have, more broadly, changes in ecosystems that, you know, affect other animals. And these changes in ecosystems or toxic effects can occur in lakes, can occur in slow-moving rivers, can occur in marine ecosystems.

What causes algal blooms?


SILVIA SECCHI: We have an agricultural system in particular that is heavily dependent on nutrients, right? So these nutrients are also in large part coming from fossil fuel production. Now, nitrogen fertilizer—artificial nitrogen fertilizer is largely the product of the use of natural gas. So what we have is more artificial fertilizer. This artificial fertilizer produces crops that are used to feed more animals, and these animals produce manure. So we have a system that has really changed from before the Second World War, which we were largely using the manure to fertilize the crops. We have not actually reduced our use of manure. The manure is still there. In fact, we’re raising more animals.

So we have these inputs into the system, and we have a climate in which the extreme events, the heat waves, the large, you know, the big storms that flush the nutrients into the water are getting worse. So it’s a combination of two kinds of things compounding each other that make a natural phenomenon worse all across the planet.

Why are harmful algal blooms so damaging?


SILVIA SECCHI: We have become perhaps more aware of these blooms because of the acute effect, right? When they impact our water sources and people can’t drink, where they close beaches because—and people can’t go outside because of the effects of—you know, the toxins are airborne and get on people’s skins, we get really scared, but more broadly, what these nutrients are doing is they’re profoundly changing our ecosystems.

So think about what is happening in the Gulf of Mexico, where the continuous access of nutrients coming from all the tributaries in the main stem of the Mississippi is causing hypoxia, right? So we have acute effects that we are really worried about because of human health effects, whether it’s, you know, their act on our skin or because we’re ingesting toxins when we go swimming at a beach where there is an event, a toxic event, but also the longer-term changes to our ecosystems in which we are losing, you know, the quality of the environment that allows native species to thrive, you know, native ecosystems to survive, and where we’re degrading them, where we have essentially these big blooms and then decay and hypoxia—so low oxygen or no oxygen conditions.

It’s almost like it’s moving at two speeds. The things that we see are the ones that are growing really fast and are acute, but there are long-term effects to our environment that perhaps should concern us more.

What are the economic impacts of algal blooms?


SILVIA SECCHI: The main one that people are really concerned about because you can’t escape them are the effects in terms of water treatment. So I am here in Iowa, and the Des Moines Water Works, which is the biggest water provider for the state—it provides water for about 20% of Iowa’s population—what they are doing is they are creating a backup system where they are going to be relying on groundwater, if necessary, because if we have algae bloom on both the rivers that the waterworks uses as a water supply, you know. They won’t have water good enough essentially to—for us to drink. So this is, like, the big concern. What do we do, and what is the cost—right? —of upgrading our infrastructure, or, if you have an emergency, providing bottled water or alternative water sources to people?

But the longer-term effect—which is associated to these ecosystem changes, if you will—is the effect on recreation. So there are places like Florida that are really dependent on the—their economy is heavily dependent on tourism. And, you know, you don’t want to become known as the red tide state, right? Similarly, in the Great Lakes, recreation is very important, and fisheries are very important, whether we’re talking commercial fisheries that can be impacted or recreational fisheries that can be impacted. So I would say the recreational effects can be a really broad, can be—you know, if you don’t have birds to look at, the bird-watching destination is no longer going to be one. If you don’t have great local food—right? —which, you know, in parts of the Gulf of Mexico is a draw for tourism, then that affects your economy. So I think this second set of issues is particularly understudied.

How good are scientists at forecasting harmful algal blooms?


SILVIA SECCHI: I think we’re not very good. We’re getting better, but we’re not very good. Right? So we don’t really have a structure at the national level. You know, like, we have the National Weather Service that, you know, has really put a lot of resources in predicting certain types of events like, you know, tornadoes or derechos. We don’t have things like that yet for algal blooms. We are developing tools like using remote-sensing, you know, satellite imagery to figure out where the blooms are. What is important is to have predictive capacity to show where they are and where they’re going—right?—because what is really important is where they affect human populations for these acute type of events where you don’t want to have people at the beach, right? You don’t want to have people drinking that water.

So there’s more work being done, but we’re not there where I would say, oh, don’t worry about it because, you know, we’re all ready to go, you know, we have a, you know, kind of, like, different levels of alert—right? —and we have protocols in place to respond to the different levels of alert. We don’t really have a systematic national level approach to this problem yet.

What can be done about this problem?


SILVIA SECCHI: I would say there are two levels of response, and really, it’s a continuum. You know, there are things that you can do when, once they have occurred—right? —so, you know, the closing of the beaches, you know, the treatment of the water, the advisories not to go outside. But really, the problem will only be solved if we address its root causes, its dual root causes, right? Climate change has to be at least slowed down. And all these excess nutrients into our water systems have to be addressed. Unless we really take care of the root causes of the problem, we’re always going to have – we’re going to get worse, you know, worse blooms more often, and it’s going to keep costing us more. If you will, this is the same thing as with climate change. If we don’t mitigate climate change, we’re going to have to adapt to it, right? If we don’t resolve the root causes of this problem, we’re going to have to spend more and more money to live with them, whether it’s moving away from surface water or coming up with more expensive water treatment methods or losing economic activity in areas where these blooms are becoming more and more prevalent.

How are reporters doing covering issues around algal blooms?

(Posted June 15, 2022 | Download Video)

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