Bringing our lakes and oceans back to life: how to deal with algae blooms and polluted waters

An ecologist, government official, thermodynamicist, and algaecidist discuss John Todd's eco-solution

[Algae bloom in Lake Erie : NASA satellite photo]

John Todd developed an extraordinary nature-based solution to cleaning up the toxic waste in our rivers and wetlands, and to deal with the pervasive algae bloom problem. In our last article/podcast, Paul O’Callaghan discussed John Todd’s idea. This article continues exploration of Todd’s idea. Two books I like “Godel, Escher, Bach” by Douglas Hofstadter, and “The nature of economies” by Jane Jacobs use a dialog form to discuss ideas. They were one of the nudges for me to try using this dialog form for this article.

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Lauren, a local government official: We have a big problem on our hands. Our county lake is absolutely choked with a harmful algae bloom, and it's devastating everything. The bloom is so thick it's depleting the lake of oxygen, leading to massive fish kills. It's an eyesore, of course, but more than that, people are avoiding the lake entirely for recreation, and our local economy is really taking a hit. It's all stemming from agricultural runoff from the surrounding farms, dumping excess nutrients into the water.

Ed the ecologist: Lauren, what you're describing in your county lake isn't an isolated incident; it's a global epidemic that's rapidly intensifying. We're seeing these harmful algal blooms proliferate in freshwater bodies, coastal areas, and even parts of the open ocean all over the world. They're a direct consequence of human activity, primarily nutrient pollution from agriculture, but also from urban wastewater and industrial discharges. These excess nutrients act like a super-fertilizer for certain types of algae.

There are numerous forms of algae, like phytoplankton and diatoms, which are essential to healthy aquatic ecosystems. But the real culprits in these blooms are often cyanobacteria, commonly known as blue-green algae. These aren't true algae, but bacteria that photosynthesize. When they bloom, they don't just create that thick, scummy layer that blocks sunlight from reaching underwater plants, killing them off. Many species also produce potent toxins that can be lethal to fish, wildlife, and pets. They can cause skin rashes, respiratory issues, and even severe liver or neurological damage in humans who come into contact with or ingest affected water. Beyond the immediate toxicity, when these massive blooms eventually die off, their decomposition consumes vast amounts of oxygen, creating "dead zones" that suffocate everything else in the water. We're talking about areas where marine life simply cannot survive, impacting fisheries and biodiversity on a massive scale, from the Gulf of Mexico to the Baltic Sea. It's a fundamental disruption of the planet's vital aquatic life support systems.

Aaron, who has an algaecide company: Our company is able to kill off the algae with chemical treatments that target the bloom directly.

Lauren the government official: But the problem is that it also kills off other life forms and has made it unsafe to be in the lake water. We are worried about the chemical residues.

Ed the ecologist: Yes, the issue is that you are disrupting the natural cycles of life in the lake. The algae-cide is treating the symptom, not the root cause.

Jack the restorationist: John Todd actually discovered a technique called the Eco Machine or Living Machine, which increases biodiversity and works with natural processes. He successfully deployed variations of it in the canals of Venice and the rivers of Fuzhou, China to help clean them up. I have been studying and building with his work for years, drawing from his philosophy that "The workings and architecture of complex natural systems offer a blueprint for technological design."

[John Todd]

Ed the ecologist: Now that is a technique I would like to hear about. I am always interested in how we can increase biodiversity. How does it work?

Jack the restorationist: Todd's whole idea is built around what he calls "biological intelligence." It's this powerful concept that all of life's different kingdoms working together can actually solve problems that have been around for billions of years. So, an Eco-Machine is essentially a system we build that borrows nature's best tricks for cleaning up dirty water. Think of it like recreating a little river system, complete with its own wetland filters, but supercharged. We pack in a much higher concentration of those amazing life forms that naturally purify water, putting them in an environment that really lets them do their best work.

For complicated types of wastewater, these systems often use a series of tanks. For example, in the very first one up in Cape Cod, Todd used 15 clear fiberglass tanks, each about as tall as a person. Each tank gets filled with water, and then we introduce all sorts of different life forms collected right from local ponds, marshes, and streams. We're talking plants, bacteria, fungi, tiny protozoa, small invertebrates, and even fish. The trick is to create slightly different habitats in each tank, so all these various organisms can really get to work on their specific jobs within the nutrient cycles. The bacteria are busy breaking down organic stuff and toxins, while fungi create these intricate networks to move nutrients around. Plants soak up dissolved nutrients and pump out oxygen through photosynthesis, and the little animals keep populations of algae and bacteria in check by grazing on them. As water flows from one tank to the next, these organisms naturally sort themselves out, forming these interconnected mini-ecosystems.

Todd even calls this "cellular design," because each tank acts like a specialized cell within one big, living organism. This setup makes the system really flexible; you can expand it if you need more capacity, shrink it if you don't, and even make improvements without having to take the whole thing apart. He's big on creating "steep gradients" between tanks, meaning quick changes in conditions that encourage a wide range of different biological processes. He also focuses on "mineral diversity" by adding various rocks and powders to give a rich foundation for microbes, and ensuring "high exchange rates" by maximizing the surface area where the water interacts with the living organisms, like plant roots and specialized "ecological fluidized beds." Plus, he likes to mix things up with "periodic and random pulsed exchanges," like varying light or flow, which actually makes the whole system tougher and more adaptable, just like nature itself.

Lauren the government official: What are the different nutrient cycles in a healthy lake?

Ed the ecologist: In a healthy lake, there's this incredibly intricate and beautiful web of cycles always working behind the scenes to keep life going and the water sparkling clean. Think of it like the lake's very own metabolism, constantly processing and recycling everything. And at the heart of it all is the microbiome. That's the huge, diverse community of bacteria, archaea, fungi, and all sorts of other tiny organisms living everywhere in the lake, from the open water to the murky mud at the bottom, and even clinging to plants and animals. This unseen workforce is basically running the show when it comes to transforming nutrients.

First up is the organism cycle, or what we usually call the food web. It kicks off with microscopic critters like phytoplankton, which are sort of like the plants of the water, turning sunlight into energy. Then, tiny animals called zooplankton munch on these phytoplankton, keeping their numbers in check. Those zooplankton, in turn, become food for bigger invertebrates and small fish, and the chain continues up to larger fish. When any of these organisms, big or small, poop or die, the microbiome steps in as the ultimate cleanup crew. All those different bacteria and fungi in the water and especially in the sediment break down this organic stuff, releasing crucial nutrients right back into the water.

There’s also another relationship: aquatic plants and their microbiome. Plants actually release sugary compounds, called exudates, from their roots. These exudates act like a beacon, drawing in and feeding specific microbial communities nearby. And in exchange for this sweet treat, these helpful microbes break down complex organic matter, making vital nutrients like nitrogen and phosphorus easy for the plants to absorb. Some even pump out growth-boosting stuff or protect the plants from disease. This amazing partnership makes sure nutrients are used efficiently and don't just pile up.

Underneath all these living interactions are the essential biogeochemical cycles, which are almost entirely run by the microbiome. Take the nitrogen cycle, for instance. Different microbial groups are like specialized factories: some bacteria convert ammonia from decaying stuff into nitrates that plants can use, while others, in low-oxygen areas, can even transform excess nitrates into harmless nitrogen gas, letting it float back into the atmosphere. The phosphorus cycle sees the microbiome making phosphorus available from sediments, then locking it back up when organisms die. For the carbon cycle, microbes decompose organic matter, sending carbon dioxide back to the water for plants to use again. They're involved in the oxygen cycle by producing it through photosynthesis or consuming it. Even the sulfur cycle relies on microbes converting sulfur compounds into different forms that other life needs. The bottom line is, how healthy and diverse a lake's microbiome is directly impacts how well and how resiliently all these interconnected nutrient loops function.

Lauren the government official: Wow, that is a lot going on in a lake!

Ed the ecologist: Yeah, when some of these cycles break down or become unbalanced, the ecosystem loses resilience and can not recover from disturbances like nutrient pollution.

Jack the restorationist: Part of the key with Todd's approach is that we give these cycles a chance to reestablish and strengthen. In the polluted lake environment, beneficial microorganisms can not compete with the algae because conditions favor the bloom. But in the Eco Machine tanks, we create optimal conditions for diverse communities. The microorganisms Todd discovered could even break down heavy metals and crude oil by incorporating them into their cellular processes or transforming them into less harmful compounds.

The brilliant part is that polluted water goes in one end, and after flowing through all the tanks over about 10 days, it comes out clean enough to drink. But it is not just clean, it has been enriched with beneficial organisms, nutrients in proper ratios, and what Todd calls "biological intelligence."

Aaron the algaecidist: But I think the algaecide is quick and we are done with it.

Ed the ecologist: But not if we want to keep the lake healthy long term. You will have to keep applying chemicals every time the bloom returns.

Jack the restorationist: Exactly. Todd's approach does not just remove the problem, it builds the lake's capacity to prevent future problems. When we release the treated water back into the lake, we are actually seeding it with beneficial microorganisms that can outcompete the harmful algae naturally. It is like probiotics for the ecosystem.

Lauren the government official: This sounds promising, but what about directly within the lake? Can these Eco Machines work out in the open water to specifically deal with our algae problem?

Jack the restorationist: That's a great question, Lauren! See, for situations exactly like your lake, where you've got an algae bloom happening right out in the open water, John Todd and his team came up with a special kind of Eco-Machine they call the Aquatic Restorer. The cool thing about it is that instead of being a big setup on land, it's actually located right there, floating in the middle of the lake itself.

It's essentially a system of floating platforms that we place directly in the water. Each platform is connected to a special upwelling filter at the bottom that actually draws water from the nutrient-rich muck, or sediment, at the lakebed. These Restorer units are designed with various wetland plants, sometimes even shrubs and small trees, growing right on them. Plus, they've got special materials that create a perfect home for huge populations of beneficial microbes, and they even include an aeration system to get oxygen flowing. This whole setup allows the organisms living on and within the Restorer to actively eat up all those extra nutrients and organic pollution from the lake. It essentially slows down and even reverses the problem of eutrophication. It does this by pulling that nutrient-packed sediment through the bottom filter and into these specialized zones where bacteria get to work. Those nutrients get processed and then become readily available for the plants on the platform and for zooplankton, instead of feeding the harmful algae. This process actively cleans up accumulated sediments, strips out excess nitrogen and phosphorus, reduces organic matter, and, most importantly, gets rid of those ugly algal blooms.

It's a much more streamlined unit, super easy to install and you can scale it up or down depending on the size of the lake. Typically, you'd put one unit in for every half to one acre of water, and each one can circulate around 100,000 gallons of water per day. It's a direct, on-the-spot solution that brings the biological intelligence of the eco-machine right to where the problem is.

Ed the ecologist: That is fascinating! So it is not just a land based facility, but a direct intervention tool for the lake itself. Have these Restorers been successfully applied elsewhere for lake restoration?

Jack the restorationist: Absolutely. The first Restorer, powered by a windmill and solar panels, was launched in a fifteen acre pond on Cape Cod in the fall of 1992. This pond was severely contaminated by twenty million gallons a year of wastewater from an adjacent landfill. Within a year, a positive oxygen regime returned, and EPA priority pollutants were absent. By 1995, sediment depth was reduced by over two feet, with large reductions in phosphorus, ammonia, and organic nitrogen. The pond's overall health and biodiversity continued to improve dramatically.

Since then, Restorers have been built in other states and internationally. For example, a large Restorer in Maryland was installed in 2001 on a nine million gallon wastewater treatment lagoon receiving high strength waste from a poultry processing plant. With twenty five thousand native plants, it significantly reduced sludge removal needs, lowered electrical requirements, and brought the facility into compliance with its discharge permit.

Another dramatic success was a half mile long Restorer built on a putrid, sewage laden canal in Fuzhou, China. It has eliminated the foul smells, cleared the water, and attracted fish, butterflies, and birds back to the urban area.

[Hawaiian Lake Aquatic Restorer - from John Todd Ecological Design]

Perhaps my favorite story is from a resort in Hawaii. Restorers were used to cleanse an unsightly, algae laden five acre brackish pond in the middle of a golf course. After cleaning the pond, the Restorers now support the culture of 80,000 Pacific white shrimp, 300,000 oysters and 60,000 fish for the resort, transforming a liability into a major asset.

Tatiana the thermodynamicist: If I may interject some perspective from a thermodynamics standpoint...

Ed the ecologist: What could thermodynamics have any relevance here?

Tatiana the thermodynamicist: Well, it is a system with many components, and we know that there are behaviors that systems like these tend towards. There are equilibrium states, which is kind of like when the lake goes dead, everything uniform and static. And there are far from equilibrium states, when there is a lot of life and active nutrient cycling.

Ed the ecologist: I did not know ecological systems could obey thermodynamics principles.

Tatiana the thermodynamicist: Yes, non-equilibrium thermodynamics can give us insight into how cycles and processes self organize. Howard Odum was a famous ecologist who applied ideas of non-equilibrium thermodynamics to understand ecology, and also used it to help put a scientific basis on agroecology and regenerative land based practices.

Ed the ecologist: What is non-equilibrium about this?

Tatiana the thermodynamist: Well, we can think of a healthier ecosystem as being further from equilibrium, it is able to generate more complex organization and maintain more energy flows. Ilya Prigogine was a famous thermodynamic chemist who wondered why the Belousov Zhabotinsky reaction would oscillate with colors when it seemed like it should go to equilibrium. The BZ reaction is a stunning chemical demonstration where a colorless liquid can spontaneously turn blue, then red, then clear again, repeating this cycle for minutes. You would expect the colors to just mix and stay a uniform color as the reaction uses up its ingredients, but instead it keeps cycling, showing that complex order can arise far from a simple, static balance. He realized that far from equilibrium, organized structures would spontaneously form, during what scientists call a phase transition. It breaks the symmetry of sameness. These structures he called dissipative structures. And as you move even further from equilibrium, its possible another dissipative structure will form in yet another phase transition.

Lauren the government official: That all sounds very abstract. What does this have to do with the lake and its lifeforms?

Tatiana the thermodynamicist: Well, we can consider these nutrient pathways as being loops, autocatalytic cycles that catalyze themselves. They are dissipative structures that form when we have more absorption of the sun's energy by diverse phytoplankton communities. That energy gets used by zooplankton that feed on the phytoplankton, which in turn feed fish, which produce waste that feeds bacteria and plants. That is the lake's normal healthy state, energy flowing through multiple interconnected cycles.

Jack the restorationist: So what I am doing with Todd's Eco Machine and these Aquatic Restorers is creating more dissipative structures?

Tatiana the thermodynamicist: Exactly! Todd's solution actually pushes the system to being more far from equilibrium, which generates even more nutrient loops and energy pathways. The system becomes able to absorb more energy and do more useful work with it. The algae-cide solution might save some fish temporarily, but it kills off the life forms that create these beneficial structures, keeping the system closer to the sterile equilibrium state.

Ed the ecologist: So what about when algae blooms happen?

Tatiana the thermodynamicist: Well, the algae suddenly have access to excess nutrients from agricultural runoff, so they proliferate rapidly, they are moving far from equilibrium. But we have to look at the larger system, which is actually moving toward equilibrium because the algae are causing other life forms to die off by consuming all the oxygen and blocking sunlight.

Ed the ecologist: Sounds somewhat like a cancer.

Tatiana the thermodynamists: Yes, cancer involves certain cells growing very rapidly. Candace Pert proposed that some cancer cells might be immune cells trying to clean up toxins, but because there are so many toxins, they multiply out of control. The cancer cells are moving further from equilibrium as they proliferate, but they are out of communication with the rest of the body's systems. They start destroying the body's other functions, so the whole body moves closer to equilibrium, losing its healthy dissipative structures and functions. Cancer is a far from equilibrium subset causing the larger system it is embedded in to move closer to equilibrium

Lauren the government official: So it sounds like we could make our lake even healthier than it was before with this Eco Machine method, or the Aquatic Restorers directly in the lake. Should we also create more habitat around town?

Ed the ecologist: Yes! If we restore our streams to have more natural curves, shallow and deep sections, fallen logs and debris to slow the flow, we create conditions for more biodiversity. Often when we let creeks flow naturally, we get a series of connected wetlands and ponds. These are exactly the kinds of habitats that would each create their own nutrient loops and dissipative structures, then blend into an even more robust system when connected.

Lauren the government official: Could this work for our town's wastewater too?

Jack the restorationist: Absolutely. Nature organically has cleaning processes built in. Todd's system at places like Findhorn, Scotland uses a series of tanks, each one processing different aspects of the waste. Each tank creates individual specialized habitats, some for breaking down solids, others for converting ammonia, others for removing phosphorus. It is mimicking what happens in natural wetland systems but in a controlled, optimized way.

The first tanks might have anaerobic bacteria breaking down complex organic molecules. Middle tanks could have aerobic bacteria converting ammonia to nitrates while plants absorb excess nutrients. Final tanks might have fish and aquatic plants polishing the water and adding beneficial microorganisms. For instance, in the Providence, Rhode Island system, they use translucent tanks with water hyacinths for initial purification, followed by engineered "tidal" marshes with bulrushes, then more diverse tanks with fish, snails, and bivalves. After about 10 days, sewage becomes clean water plus beneficial organisms. This system even significantly reduces heavy metals and coliform bacteria.

[diagram from John Todd Ecological Design]

Tatiana the thermodynamicist: Yes, each of the tanks is its own non- equilibrium state where the dissipative structures, the autocatalytic loops, develop naturally. It is mimicking what nature does with series of wetlands, working as the kidneys of the earth, cleansing water through biological processes.

Lauren the government official: So the agricultural runoff is like a toxin overwhelming the lake's natural cleaning capacity.

Tatiana the thermodynamicist: Exactly. And we can think of modern agriculture in these thermodynamic terms too. We put synthetic fertilizers into soil, which initially ramps up growth, moving the system further from equilibrium so we can produce lots of food. But it is destroying the soil's natural dissipative structures, the complex networks of mycorrhizal fungi, bacteria, and soil organisms that maintain healthy nutrient cycles. So while crop production might increase short term, the whole agricultural system is moving toward equilibrium as soil moves towards becoming lifeless dirt. For long term food security, we need regenerative agriculture that builds these soil communities.

Lauren the government official: Sounds like I need to work with my colleagues on measures to help educate farmers in our district and support their transition to these methods.

Ed the ecologist: This thermodynamic perspective is fascinating. Does it describe rewilding efforts too?

Tatiana the thermodynamicist: Yes! By increasing biodiversity and trophic cascades, like when wolves return and change deer behavior, allowing forests to recover, we create more dissipative structures throughout the ecosystem. These increase soil health and vegetation biomass, meaning more sunlight gets captured and more complex energy flows develop. The system moves further from equilibrium and becomes more resilient.

Ed the ecologist: Does this extend to climate? I have heard that forests can actually increase rainfall.

Tatiana the thermodynamicist: Yes, this is cutting edge research, but biodiversity and climate are deeply interconnected. When we shift ecosystems into more far from equilibrium states with greater biodiversity, it affects water cycles and regional climate patterns. The small water cycle, where forests transpire moisture that falls as local rain, is itself a dissipative structure. Healthy ecosystems with these climate regulating structures can help buffer against extreme weather events like droughts and storms. The key insight is moving the whole Earth system toward states that are more compatible with the complex life it supports.

Lauren : Wow extraordinary. A lot to think and digest here, with a lot of wider implications for water quality, biodiversity, and climate.

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