What’s killing Florida’s Indian River Lagoon?

Now that the summer algae has settled, it is time to get serious about educating ourselves on Florida’s environmental history and ask ourselves if this is what Florida will look like for future Floridians — or if we will do better. I will post one long blog post a month picking apart different parts of the Florida Environmental Clustermuck that is Lake Okeechobee, The Everglades, Florida Bay, the Indian River Lagoon and the West Coast area.

TLDR: The argument that septic tanks are more responsible for the blue-green algae blooms in the Indian River Lagoon than Lake Okeechobee discharges is misguided (understatement). We really don’t know how much nutrient reduction we have to get to to bring the Indian River Lagoon back to life. The one study that is often cited as proving that septic tanks are more responsible than discharges actually doesn’t compare septic tanks to discharges — it focuses almost solely on whether septic tanks are contributors to nutrient pollution, not if septic tanks contribute more than discharges. If we want to look at that, we have to design an experiment to measure it. We’ve got about seven to eight months to design this experiment because the blooms will be back next summer. In fact, the lagoon is already seeing hints of blooms again.

The argument: septic tanks v. discharges

I wonder who was the first person to say, “you know what we should put underneath this news article? A comment section. Ya know, so people can have like thoughtful, well-informed discussions about the article at hand. I think it will really make the world a better place.”

I searched high and low for the scientific sources behind these comment-section claims. These sources rarely even come up in newspaper articles. And perhaps that isn’t surprising. Reading scientific literature is painful. So many words and you are always reading between the lines. Why use titles like “Of Planchettes and Pickets: Spiritualism, the New Woman, and Literary Modernism, 1880–1930” when a simple “Victorians were Very Upset about Lesbians and Séances” would do?

The comment fights I found above are regarding the ongoing debate of whether septic tanks or polluted discharges from Lake Okeechobee are responsible for the blue-green algae blooms that occurred in the Indian River Lagoon this summer.

What’s got you down, Indian River Lagoon?

In case you aren’t up to speed on the debate surrounding the sources of nutrient pollution in the Indian River Lagoon, here’s the poop scoop:

Despite the well-known biodiversity of the lagoon, there are few studies on nutrient pollution in general, and even fewer on septic tanks. And there’s essentially one 2015 study causing the internet comment section fights that evaluates septic tank pollution in the Indian River Lagoon. Here it is. Other lagoon studies touch on septic tank pollution, but this is the only one that dives into it. The author, Dr. Brian LaPointe, takes all sorts of poop samples all over the Indian River Lagoon to conclude that septic tanks are a major contributor— if not the most significant — to nutrient pollution in the Lagoon.

Large scale consequences of large scale pollution. Photo by Greg Lovett, taken on June 29, 2016 in Stuart, Florida.

I examined this paper at length. I spent an embarrassingly long amount of time on this paper because it is being used by some (not going to name any names SUGAR) to escape any responsibility for the blue-green algae blooms. And, therefore, taking any significant action to deal with this pollution.

I sent a collection of my thoughts to one of my professors from Duke University — Dr. Stuart Pimm — And he pointed out something I failed to ask which would have been a huge time-saver. Did Dr. Lapointe ask the same question that I, or others, are trying to answer?

Samples sites from Dr. LaPointe’s paper. He takes samples of different forms of nitrogen, phosphorus, salinity, carbon and nitrogen isotopes, and looks at these levels in the context of rainfall to determine if it is true that septic tanks are leaking raw sewage into the Lagoon and this sewage is just sitting around, waiting for some algae and a perfectly hot Florida summer day.

OMG DUHHHH! How dumb am I? Seriously. How freaking dumb am I. I spent so much time picking this apart and I just had to look at the question again.

The question Brian LaPointe answers is this -

Do septic tanks contribute to nutrient pollution in the Indian River Lagoon? He concludes, why, yes. Yes, they do.

But newspapers, the media, policymakers, and people getting in internet fights have often interpreted this question as this -

Are septic tanks more or less responsible than Lake Okeechobee discharges for contributing to this summer’s algae blooms?

Well, well, well. Turns out we have not conducted a comprehensive study that looks at septic tanks and discharges. Dr. LaPointe’s question and therefore methods are aimed at determining if septic tanks are polluting the lagoon — not if septic tanks are polluting the lagoon more than Lake Okeechobee discharges. This is key. If you want to get technical, he specifically measures nitrogen isotopes (which can be used to determine the source of nitrogen pollution, but they are not fool-proof) along the lagoon and compares them to the level of nitrogen isotopes in an algae bloom that occurred during his study after Lake Okeechobee discharges in 2013. His results indicate that there were similar levels of nitrogen isotopes in the lagoon and in the algae bloom. Translation: there was human poop in the lagoon and human poop in the algae bloom. He also compares the nitrogen isotopes found in the river to nitrogen isotope levels found in other areas that deal with severe urban runoff, such as the Northeast. Again, this may indicate that at the time of the sampling, isotope levels suggest the river is experiencing urban runoff in the form of raw human sewage. But it does not evaluate the episodes that happened this summer after the releases from January 2016 until the blooms started in July.

Basically, his results may prove that septic tanks are polluting the river, but they do not prove that septic tanks contribute more nutrient pollution to the Indian River Lagoon than Lake Okeechobee discharges or vice versa — because that was never measured. Because comparing septic tanks and algae blooms was not the primary intent of his study, we can’t conclude that discharges are not mostly or partly responsible for the blue-green algae blooms this summer.

Interview with Dr. Brian Lapointe on the septic tank issue. He even has trouble attributing everything to septic tanks.

No doubt that there are issues with urban runoff because Florida is covered in concrete. No doubt that there are issues with septic tanks because there are hundreds of thousands of septic tanks along the Indian River Lagoon counties. But Lake Okeechobee discharges recently surpassed 200 billion gallons for this summer. Discharges through August added 250,000 pounds of phosphorus to the St. Lucie Estuary. That’s a lot of poop. And to say that this has no or little effect on the algae blooms in the lagoon — not only is it not supported by the scientific literature, but it also just defies common sense. And we can’t forget that some people have a very, very strong financial incentive to keep polluting.