A phosphate spill spelled disaster for marine ecosystems. Can research mitigate future harm?

A person with short hair in a life jacket pulls a white plastic bucket out of a body of water while kneeling in a boat.

Eckerd student samples water near Skyway after the Piney Point spill that occurred earlier this year (Shannon Gowans/Eckerd College).

On March 26, 2021, a leak was discovered at Piney Point, a phosphate mine and fertilizer plant in Manatee County, Florida. One wastewater pond’s plastic liner tore and leaked thousands of contaminated water into the sediment. To prevent the entire leaking container from collapsing, over 200 million gallons of wastewater were pumped into Tampa Bay to lessen pressure on the structure. A state of emergency was declared by Florida Gov. Ron DeSantis for Manatee County on April 3, requiring people to evacuate the area. This ecological disaster has impacted the entire Tampa Bay community, including the research of Shannon Gowans, professor of biology and marine sciences at Eckerd College in St. Petersburg, Florida.

I sat down with Gowans, who specializes in cetacean (or marine mammal) research at Eckerd. Gowans leads the school's dolphin project and collaborates with Amy Siuda, an Eckerd Associate Professor of Marine Science, on a microplastics monitoring project. 

When I sat down with Gowans, she told me that the red tide this past summer “was one of the most severe ones I've ever seen. I've been here now 18 years and I've never seen the level of fish kills that we saw in Tampa Bay.” 

In the following conversation, we discuss how the dolphin and microplastics research projects have been impacted by the Piney Point Spill and the past summer’s red tide event. We also discuss the value of long term studies and the insight they provide when dealing with ecological disasters such as Piney Point.

This interview has been edited for clarity and length. 

Kaitlyn Copland: What research have you conducted that is related to the Piney Point spill? 

Shannon Gowans: Amy Siuda and I have had a long term monitoring project looking at microplastics in Tampa Bay. One of our monitoring sites that we've been monitoring for quite some time is close to the Sunshine Skyway, a bridge not that far from where the outflow was.

Our initial concern was: how did this plastic barrier break down? And is it shedding microplastics into Tampa Bay? We found that the values that we got while the Piney Point outflow was going on were much, much higher than we'd ever seen before in our years of monitoring. 

We then set out to try to collect some more samples and try to see what was going on––and also to see if we could get some samples much closer to the outflow. We're again seeing some elevated levels, but not as high as they had been.

The question is: were we getting elevated out-flow levels from Piney Point? There were so many boats in the area that it might have been stirring up sediments that may have had microplastics in them. Or, was it after they started pumping the water that caused all this turbulence and registered things?

Overall, we are not sure if these statements hold true. We're continuing on with our long term monitoring to see what happens. Microplastics were not the first level of concern with something like Piney Point, but because we had this long term monitoring program it was worthwhile to investigate.

KC: Can you share how the dolphin project has been impacted? 

SG: Currently, nutrient pollution is unlikely to harm marine mammals because the pollutants are not problematic for mammal’s health. We're much more concerned about how the nutrient input that is having a long term impact on the ecology of Tampa Bay, and how that relates to these top predators.

We know that when we have harmful algal blooms that lead to large fish kills, we end up with issues with our dolphins because their food source has been largely removed. 

KC: How has the past summer’s red tide event affected the current dolphin population? 

SG: We didn't see an uptick in mortality directly due to Piney Point, but we are concerned about what's going to happen given the prey base that got lost with that red tide. It's difficult to tie those two events completely together, but it is likely that these events may be related; the red tide was already present before Piney Point came in, but the nutrients that were released would fuel an algal bloom––which is exactly what we saw.

KC: Was this past summer’s red tide more severe than in recent years?

SG: One thing is that it was within Tampa Bay itself and happened over a relatively short time period. That may mean that it didn't impact all of Tampa Bay, which may mean fish and animals that are feeding on fish may be able to just move somewhere slightly different and find better conditions. 

So, we may not see that large an impact because it was a very intense event but over a short time period. In 2005, we had an exceptionally long red tide event that actually persisted over several years––there were high levels of red tide over several years. They weren't as high as we saw last summer, but that's what had a really profound impact on the dolphin population because they went through a long spell where their food––their prey––was produced. So, both can be problematic and it's just going to be waiting and seeing what we end up with.

KC: Do you have any thoughts on how this spill might play out over the coming months, and maybe even into the next year?

SG: So much depends on what happens with the interaction with the currents and the tides. At the initial input of nutrients, they were dispersing through Skyway Bridge and moving outwards into the Gulf. Piney Point was initially very, very strong in Tampa Bay, but that has dissipated into the Gulf of Mexico. 

That's also going to be something to watch because to remove (a lot of these nutrients) from the system they either have to be diluted in a larger quantity of water, or they end up in the sediments. If they get out to the deeper water into the sediments, then it's harder to have storms that stir them up. In the shallow waters like Tampa Bay, those sediments can be easily disturbed by storms. So, again, it's going to be seeing what happens to that nutrient influx. 

We don't have the high algal counts right now that we were seeing earlier in the summer, but the nutrients haven't completely disappeared from the system. We're actually just starting to head into the time when we typically see larger red tide events, because red tide is typically a fall-winter event. Seeing what happens to those is going to be something that we want to watch long term––and really looking at what kinds of larger-scale, ecological changes may be happening.

KC: If an event similar to Piney Point was to occur again, what do you think needs to happen? 

SG: What needs to happen is to have regulations to ensure that, if we have these phosphate reservoirs, (they) need to be well maintained, and, ideally, (regulations) working on removing them so that they're no longer at this bar. That's the work of land use policies and a lot of other people. 

We need to change legislation to hold the companies that are producing these pollutants responsible. Even if the companies sold or closed down, they’re still the ones who created those pollutants.

KC: Do you have any final thoughts, or something important to share about like the Piney Point spill regarding your research?

SG: I think one of the things that Piney Point shows is the value of having long term monitoring plans where we know what happened, what the conditions were like before something happens so that we can see what happened during the event, and then afterwards. 

If you go in at the crisis point, you don't know what the conditions were like beforehand. Yes, you can see what they're like during the crisis point and what happened moving forward, but you don't have that comparison. If we really want to understand what's going on with our ecosystems and, if there is a catastrophic event, be able to then try to turn them back to those pre-existing conditions, we have to know what those conditions were. We don't know if all we ever do is respond to catastrophe. We have to be monitoring (conditions) in the long term to see what's going on and not waiting until it's a crisis point.

The value of research

Ultimately, long term monitoring research projects provide great value when mitigating ecological disasters similar to Piney Point. Gowans’ research has discovered that plastic levels have increased significantly and the dolphin’s prey population––fish––have decreased. 

It is currently undetermined if the spill is the source of the elevated microplastic levels and increased severity of the red tide that killed the fish. This is an event that will play out over the coming months, and its effects will be determined by currents and tides.

For more information and updates on the Piney Point spill, visit Protecting Florida Together.

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