An Unlikely Hero:

Periphyton's Role in Everglades Restoration

Meeting Periphyton

A little about me, Periphyton

Periphyton is a community of organisms and matter working together in harmony (at least when things are in balance). It is a melange of various organisms, including algae, cyanobacteria, fungi, microbes/diatoms, plant detritus (decaying matter), and microinvertebrates .

The Food Web

The rich community of matter that creates periphyton serves as the foundation of the food web for the Everglades and throughout South Florida.

Periphyton's Role in Keeping Things Clean

Periphyton's most important role is maintaining the physical environment of the marsh, providing oxygen through photosynthesis, cleaning the water and providing food. That's a lot!

Now that we know what periphyton is and how it fits into the natural world of the Everglades, it’s time to learn about a new role for our intrepid community builder.

History, Lawsuits & a Hero Emerges

To early settlers, the unruly and beautiful landscape of South Florida and the Everglades, the long-time home of the Seminole and Miccosukee peoples, seemed ripe for taming. Enduring hardship and setbacks, hardy pioneers made their way into the scrub seeking to claim land and bend it to their will. So began the alteration of the Everglades.

LATE 1880'S

Wetlands are drained, canals built, and land cleared to make way for development and agriculture.

EARLY 1900'S

Devastating hurricanes caused catastrophic flooding from Lake Okeechobee, prompting the Government to build the Herbert Hoover Dike and engineer more flood control. More canals are built and a major road (the Tamiami Trail) connecting Miami to Tampa bisects the southern Everglades.

1947

Everglades National Park is established and Marjory Stoneman Douglas, a forward-thinking journalist and environmentalist, publishes The Everglades: River of Grass.

1948

Congress authorizes the Central and Southern Florida (C&SF) Flood Control Project precipitating the completion of the myriad of canals that now transect South Florida, drying up half of the Everglades and affording the possibility of large planned communities and the agricultural district. These projects were largely completed in the 1950s.

The Everglades, the River of Grass: before and after

1960s

"Big Agriculture," mostly sugarcane, dominates the land south of Lake Okeechobee. With an agricultural boom comes an increase in fertilizer use.

1972

The Clean Water Act is passed by Congress, triggering a national initiative to clean up America's polluted waters.

1988

The Federal Government, pursuant to the Clean Water Act, sues the State of Florida. The lawsuit alleges that the State hasn't done enough to protect South Florida's waters from the devastating effects of agricultural pollution.

1991

Governor Lawton Chiles, on behalf of the State of Florida, settles the lawsuit with the Department of Justice, paving the way for Everglades restoration.

1994

The Florida legislature enacts the Everglades Forever Act. Shortly thereafter a water quality standard for phosphorus of a numeric nutrient standard of 10 parts per billion is established. Periphyton is selected to be used as the medium to test for phosphorus load, due to its sensitivity to phosphorus.

Early 2000s

The Comprehensive Everglades Restoration Plan (CERP) is put into place. Congress requires progress reports for Everglades restoration every 5 years.

2005

Phosphorus testing begins and periphyton, our hero, gets his cape and goes to work as the measure of water pollution.

Some Notes Before Digging In

Although phosphorus can be beneficial because it causes things to grow, for the Everglades, too much phosphorus is harmful.

Although it is a vital nutrient in all natural systems, phosphorus is also a fertilizer component. It flows across the landscape in stormwater runoff (urban and agriculture), harming natural areas by promoting algae growth and an overabundance of non-native plants, crowding out natural vegetation and disrupting food sources and habitats used by native wildlife. The Everglades is naturally a low-nutrient system. Even small amounts of additional nutrients can upset the ecological balance needed by the native plants and animals in the historic "River of Grass.”

South Florida Water Management District

When water quality testing began in earnest in 2005, scientists under the aegis and direction of CERP (The Comprehensive Everglades Restoration Plan) set out to collect samples of periphyton throughout  various designated basins  within the Everglades. They recorded many variables, including what type of periphyton was observed, algal composition, water measurements, diatom abundance and so much more. The two foundational datasets from this testing, that span 2005 - 2014, serve as the source of the following visualizations.

BASIN COLOR-CODING IN THE VISUALIZATIONS:

NORTHERN BASINS Blue-green colors: Basins in the North, Lake Okeechobee and Corbett/Pal Mar Orange: Ongoing testing area in the North, Water Conservation Area 1

CENTRAL BASINS Grays: Water Conservation Areas 2A, 2B & Big Cypress National Preserve Browns: Water Conservation Areas W3A & W3B

SOUTHERN BASINS Chartreuse: Shark River Slough, an important low phosphorus basin Moss Greens: Pennusco Wetlands, Oligohaline & Taylor Slough

Each  basin  is represented with its abbreviation, except where space for the full name allows.

Peri, ready to work!

THE VARIABLES USED IN THE VISUALIZATIONS

Except where noted, the visualizations below use two variables: 1. Periphyton ash-free dry mass* in grams per square meter, for periphyton, and 2. Concentration of total phosphorus per dried gram of periphyton, for phosphorus.

 *Dried samples processed in a muffle furnace and re-weighed. 

Periphyton at Work, the Data!

What happens to periphyton when it is exposed to large amounts of phosphorus? A picture is worth a thousand words.

It is always good to start off with the big picture. If we look at all of the observations collected during 2005-2014 on a scatterplot, we can see that periphyton just doesn't want to stick around past the legal limit of 10 parts per billion of phosphorus. Not only that, but most periphyton observations fall below 5 parts per billion of phosphorus.

We can really see where periphyton shows up if we look at the individual observations in each of the basins. The closer testing is to agricultural and urban areas in the Northern Everglades, the less periphyton we see. In many cases, we observe large counts of phosphorus and not a bit of periphyton.

By observing periphyton in the testing laboratory we can illustrate the relative amount of phosphorus to periphyton in each basin. We can also observe the relationship of periphyton to phosphorus within each specific testing area for each basin. (Testing was done at different locations within the basins). The larger the colored circles in the "petri dish" below, the larger the phosphorus in the periphyton sample. The smallest dots show little phosphorus but might have lots of periphyton. The circles around each basin represent the collection of all the sampling areas within a basin and are not a reflection of overall phosphorus. Both the Taylor Slough and the Shark River Slough demonstrate samples with smaller amounts of phosphorus overall. The conditions for periphyton's success are better in these basins than in other sampling sites.

And, as if we can't get enough of this stuff, a beeswarm plot shows the relationship between periphyton and phosphorus in another way. Remember floating periphyton that gets all bubbly and full of oxygen? Floating among small bugs and fish? This beeswarm chart shows us which basins support an environment conducive to floating periphyton (and all the critters that go with it). Where we see the largest counts of floating periphyton, there seem to be smaller observations of phosphorus, for the most part. But some basins have not only small counts of periphyton, but also small amounts of phosphorus, so there must be other things at play. And there are! We'll talk about those later.

A Missing Clue: Water

WATER MAKES PERIPHYTON HAPPY

What is unique about those areas that are low in phosphorus and high in periphyton? Hydrology (and diatoms)…. While different areas of the Everglades require different hydrological conditions, one thing is consistent--without water, we don't have periphyton. Optimally, periphyton does best under shallow water conditions of longer  hydroperiods , which explains why it is most abundant in certain basins like the Shark River Slough and Taylor Slough.

Restoring the water flow as closely as possible to its original state is one of the most pressing needs for periphyton and the health of the Everglades. Periphyton can then do its job of putting oxygen in the water, cleaning it and providing food. But there is more to consider regarding periphyton's health: one of the key organisms of its composition, the diatoms that microscopically hold periphyton together.

Diatoms, the Special Sauce

Diatoms are single-cell organisms and the part of periphyton that are particularly sensitive to the environment. (One might say diatoms are what make periphyton so sensitive.) Researchers have found that between 300-400 diatom species exist in the Everglades. Of those, about 60 diatom species show up the most in sampling data. And of those 60, 4 diatoms -- Mastogloia calcarea, Encyonema evergladianum, Brachysira microcephela and Fragilaria synegrotesca -- are the most dominant. Of all the diatoms observed from 2005-2014, these four diatoms comprise 66% of the average percent abundance in all samples. Of note, some diatoms like more phosphorus, but three of these dominant four do not. This is an important distinction.

CLICK ON EACH IMAGE TO SEE MORE DETAIL

Where periphyton makes a thick, white, fluffy mat, like in the Shark River Slough, one can be sure that the dominant diatoms that like harsh, low phosphorus conditions are present. Diatoms that are more phosphorus-tolerant and tend not to show up in the dense periphyton mat, like Fragilaria synegrotesca, tell us there's more phosphorus in the environment. It is no wonder that these dominant diatoms are used as bioindicators. They are the means by which periphyton reflects the health of its environment.

These small, beautiful and mighty organisms serve as the beating heart of periphyton.

Periphyton Now

WHERE WE ARE NOW AND WHERE WE’RE HEADED

While the data represented in these visualizations does not include current datasets, ongoing research has demonstrated that there is much work to be done in Everglades restoration and that, if anything, the needs for remediation are even more pressing. As we've seen in our data visualizations, periphyton has optimal growth at 5 parts per billion of phosphorus or less, even though the legal limit is 10 parts per billion. Thankfully, due to law, the public has access to ongoing reports that reveal whether or not restoration goals are being met. A more recent  South Florida Water Management District Report  (page 8) demonstrates that total phosphorus loads are steadily increasing. A diagram in the report, re-drawn here, also reflects that phosphorus loads would have hypothetically been worse had industry not used best management practices (BMPs).

Vigilance is required. What gives us a fuller picture, as we've learned, is periphyton abundance, and if phosphorus is increasing overall, even if paired with increased water flow, then restoration efforts have a long journey ahead. Where periphyton is able to re-establish in areas that have been awash in phosphorus, we have windows of hope for returning wildlife and clean water.

UNDERSTANDING PERIPHYTON IN CONTEXT

Periphyton isn't just a tool to understand and fight the loss of the Everglades; it's a living, functional symbol of respect for life and letting Nature exist as it was meant to. Life in the Everglades developed the way it did for a reason. The harsh, low phosphorus ecosystem evolved to support an intricate web of life. Introducing excessive amounts of phosphorus (and other pollutants) disrupts this balance. Periphyton is the canary in the coal mine of the Everglades.

WHAT THIS MEANS FOR SOUTH FLORIDA

While "[t]he periphyton are one small part of a large complicated ecosystem, and management of a large diverse natural system should not just prioritize maximum periphyton[,]" (T. Shannon) we can still listen to the messages our super hero is telling us and prioritize swift change. That means, for South Florida, reducing phosphorus and working towards re-establishing healthy water flows in the Everglades. Not prioritizing water solely for short-sighted consumption - but prioritizing clean water, which is immeasurably more important for all.

Lofty Goals of Letting the Water Flow to Florida Bay

WHY IS RESTORING THE EVERGLADES IMPORTANT OUTSIDE OF FLORIDA?

Taking action to remove and reverse the consequences of environmental disruption is a step towards protecting our future and our children's future. Scientists worldwide have been warning about the unraveling of environmental balance. In the same manner that the Everglades changes when pollution and adverse hydrology conditions impact periphyton, the water and the food web, similar consequences occur on a larger scale with global pollutants, warming climates and water pollution. Scientists at the  Stockholm Resilience Center  have determined "[f]rom global warming to the biosphere and deforestation, from pollutants and plastic to nitrogen cycles and freshwater: Six of nine  planetary boundaries  are being crossed, while simultaneously pressure in all boundary processes is increasing...."

Credit: Azote for Stockholm Resilience Centre, Stockholm University. Based on Richardson et al. 2023, Steffen et al. 2015, and Rockström et al. 2009

While Floridians can't change the world, they can make personal choices to support the life around them that eventually have larger impact and lessen the likelihood of these planetary boundaries being crossed. Even small choices like forgoing fertilizer, or food choices, or actively supporting practices that take care of the flora and fauna in this garden, this River of Grass, is a vote for the well-being of all, instead of the short-sighted desire of a few.


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About the Work and Data

HOW DO THEY GET THE DATA?

The scientists collect samples in the field, making note of environmental observations, and then process the samples in the laboratory, taking note of what percent of the samples from each location contain periphyton and how much phosphorus (and other elements) are observed in the same collection.

WORTH SAYING

This data shows that over time the scientists stopped collecting samples from certain basins as their focus shifted to the most productive basins. Also, as continued research reveals, testing for phosphorus in the southern Everglades reveals legacy phosphorus that has traveled through the system from the north. Using the data collected from 2005-2014 and data collected since, only now has a baseline been established.* These foundational datasets demonstrate the dynamics of periphyton abundance and the importance of monitoring to support an oligotrophic Everglades environment.

ADDITIONAL RESEARCH PROJECTS: CERP

For those wanting to stay on top of developments with the  Comprehensive Everglades Restoration Program , one can take a deep dive into the regularly published reports and updates.

 *per FIU scientist 

Sources, Credits & Thanks

DATA: Gaiser, E. 2022. Periphyton and Associated Environmental Data Relative from Samples Collected from the Greater Everglades, Florida, USA from September 2005 to November 2014 ver 5. Environmental Data Initiative. ( Periphyton Data ) Gaiser, E. 2021. Relative Abundance Diatom Data from Periphyton Samples Collected from the Greater Everglades, Florida USA from September 2005 to November 2014 ver 4. Environmental Data Initiative. ( Diatom Data ) RESEARCH & ARTICLES:  Everglades Law Center    Everglades Restoration 

 Diatoms.org  ARTICLES / BOOKS / PODCASTS / INSPIRATION: A Land Remembered, Patrick D. Smith. A historical fiction of Florida's early pioneering years including the development south of Lake Okeechobee. Craig Pittman's many books and  Florida Phoenix  articles. PEOPLE: Leah Voss, Multimedia Producer for Friends of the Everglades; Dr. Thomas Van Lent; Dr. Evelyn Gaiser; Florida International University scientists with The Gaiser Laboratory for Aquatic Ecology, Paige Kleindl & Thomas Shannon MARYLAND INSTITUTE COLLEGE OF ART & MORE The professors at  MICA  ; Cohort: Every single one; Statistics and R tutor,  Nathan Atkinson  FAMILY & FRIENDS: H (long-suffering), T & H; Fla Family (Mom +JSK especially) & LAJ (bf); G! Most of all (Malachi 4:2)

StoryMap created by

© Valerie Robbins, 12/12/2023

The Everglades, the River of Grass: before and after

Peri, ready to work!

Lofty Goals of Letting the Water Flow to Florida Bay

Credit: Azote for Stockholm Resilience Centre, Stockholm University. Based on Richardson et al. 2023, Steffen et al. 2015, and Rockström et al. 2009