Overview - Twelve Precepts of Ecological Design - Heavy Metals


Almost thirty years ago the brilliant ecologist H. T. Odum employed analytical systems models to study the infrastructures that sustain humanity. He concluded that industrial society was on a collision course with the natural systems upon which it is dependent. He predicted that a fossil fuel dominated society would overshoot the Earth's carrying capacity and as a consequence there would be widespread suffering in the twenty first century.

Odum proposed an alternative future based upon design strategies embedded in the 3.5 billion year long experience and evolution of life on Earth. He postulated that forests, rivers, prairies, coral reefs and other ecosystems contained within themselves the information and the biological knowledge essential to creating a sustainable future. If the information housed within ecosystems was decoded, a body of knowledge would become available that could be applied to redesigning farms, factories, waste systems, communities, energy production and even transportation networks.

For this new field Dr. Odum proposed the terms ecological design and ecological engineering. He went further and conducted experiments in ecological design and engineering as well as formulated some of their guiding principles. His landmark book Environment, Power and Society, published in 1971, launched ecology as an intellectual foundation for future design.

The same year, John Todd began the task of decoding information from ecosystems and applying the information to create new technologies that employed the biological complexities found in nature. The first experiments, carried out at the New Alchemy Institute and the Woods Hole Oceanographic Institution, involved designing and building engineered ecosystems for growing foods. During subsequent years these ideas were applied by Todd and his associates to the fields of aquaculture, fuel production, renewable energy development and architecture.

Much of our current work is based on the concept of linking normally unconnected sectors of society's infrastructures. This stage has been labeled industrial ecology. In broadest terms industrial ecology creates symbiotic systems throughout society which share and exchange resources internally just as ecosystems do in nature. Industrial ecologies can have high overall efficiencies because of resource sharing. Also, pollution can be mostly, if not completely, eliminated as one component's wastes is another component's energy, nutrient or materials source. An example is the growth of eco-industrial parks, which can be one solution to smart resource utilization. Another example is the use of Restorers to purify water and provide valuable secondary products as functions of the same process.


Twelve Precepts of Ecological Design

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1. Geological and Mineral Diversity Must Be Present
          It has been suggested that the biological richness of Earth is a result of the complexity and diversity of its underlying mineral structure. In areas with similar climate and weather patterns, underlying bedrock creates ecological differences. Biological responsiveness is determined, in large measure, by the rocks and minerals that make up the parent materials of rich soils. In mineral rich zones, life and be extraordinarily abundant. For example, one gram of forest soil can contain an average of 400 million bacteria, 2 million microscopic fungi, 100 thousand microscopic algae and 10 thousand protozoans.
          In particular, autotrophic bacteria represent a vital role in the development of Eco-Machines due to their ability to derive food and energy from inorganic mineral sources. These bacteria are comprised of chemosynthetic and photosynthetic forms and between the two, facilitate entire food chains. Along with the potential of these bacteria, the inclusion of biogenetically created minerals, igneous, sedimentary, and metamorphic rocks in Eco-Machines may engender biological combinations that will allow Eco-Machines to explore, invent, and redesign themselves into optimal systems.
          Among the least understood aspects of mineral diversity is its function in the formation of the mineral/organic compounds called colloids. Colloids are clay and humus particles of extremely small size, which regulate the exchange of ions (cations and anion exchange) between soils, water, bacteria, and higher plants. Some soil scientists consider colloid-based ion exchange critical to soil metabolism. Its important in planetary processes is exceeded only by that of photosynthesis and respiration.
          The vast array of sub-microscopic, electrically-charged compounds, mediating exchanges between living and non-living realms, represent major biological determinants and underscore the evolution of life. James Lovelock, the cofounder of the Gaia theory, has argued that geophysical processes, rich in minerals and orchestrated or mediated by diverse life forms, combine to monitor and self regulate planetary metabolism. On a microscopic scale, the same perspective applies to Eco-Machines.

2. Nutrient Reservoirs are Essential
          Mineral diversity provides the long-term foundation for nutrient diversity. Microorganisms and plants require nutrients to be present in available form. It carbon in recalcitrant or nitrogen, phosphorus, and potassium ratios out of balance, or trace elements not readily available, subsequent ecosystems may be impoverished in key ways. Nutrient imbalanced systems become prone to disease and subject to biological impoverishment. Over time species in such systems die out.
          Nutrient deficiencies are particularly common in systems treating food-processing wastes. In sewage treatment systems that vary widely from a carbon/nitrogen/phosphorus ratio of 100:5:1 efficiency can drop dramatically, while imbalances in trace minerals can completely alter the flora of these systems. Agricultural systems also encounter a variety of problems when soils are not carefully nurtured and protected from mineralization. Although native plants are adapted to these conditions, crops plants door poorly unless missing elements are added to the soil. Similar from a design perspective, Eco-Machines need reservoirs of nutrients captured from within various gradients of pH and oxygen so that complex food matrices can develop and be allowed to explore a variety of successional strategies over time.

3. Steep Gradients Must be Engineered into the System
          The history of planetary biota has, at its core, systems that have evolved between steep gradients in which the biochemistry of life is “flipped” between different states. By steep gradient, we mean a steep or rapid change, in terms of time and/or space in the basic underlying attributes or properties or adjacent subsystems. Steep gradients can be defined in terms of gases, like the aerobic or anaerobic states expressed by oxygen, redox potential, pH, temperature, humic, and ligand or metal related states. The functions of many steep gradient phenomena have been described in diverse and often seemingly unrelated scientific literatures. The best know of these gradient related processes are the nitrogen cycles which are central to global and ecosystem metabolism, soil ecology, waste treatment and aquaculture.
          Throughout geological time, steep gradients in a changing world have triggered dramatic evolutionary changes. Applying such evolutionary processes to Eco-Machines: polluted water traveling through a series of steep gradients created by differing subsystems can be exposed to a range of bio- geo-chemical states. In sewage and wastewater treatment processes, it is possible to design subcomponents that further accentuate and steepen the gradients. Ultimately, it is these steep gradients that provide the sequence of altered environments, which increase the number of processes for purifying water.

4. High Rates of Exchange Must Be Created
          In ecologically engineered systems the objective is to maximize the surface area exposed to the waste system without hindering the through flow of the system or the metabolism of the contained communities. Higher plants floating on water surfaces develop root complexes that provide extraordinary surface are for microbial communities, in some cases as mush as ten thousand times greater that the surface areas of comparable conventionally engineered systems.
          The surface areas and substrates to which the nutrient-laden liquid is exposed can be increased employing trickling and sand filters. Another option is to increase the rates at which water flows over biological surfaces. A danger lies in creating excess turbulence that can destroy biological communities. The rates of internal recycling, with concurrent waste stream exposure to biological surfaces, should be between 10 and 1000 times the throughput flow rate. A porous medium with a specific gravity near 1 will permit these rates while maintaining resident biological communities. Water can flow gently through the medium at a velocity of up to three orders of magnitude greater than the system’s throughput rates. Ecological fluidized beds have rapid internal recycling rates and still provide habitat for diverse benthic animal communities. Such communities can include snails and clams, attached algae, aquatic plants, and higher plants. These high rate systems are capable of maintaining exponential bacterial growth rates under conditions near optimal for the associated bacteria.

5. Periodic and Random Pulsed Exchanges Improve Performance
          In the text, Perspectives in Ecological Theory, systems ecology pioneer, Ramon Margalef discussed the significance of regular or periodic outside influences as well as that of random external events in shaping the structure and response systems of ecosystems. He suggested: “Direct reaction of organisms to environmental exchange is most useful if the environment is being altered in an unpredictable way.” This suggests that internal self-organization and self-design in ecosystems can be heightened be exposure to periodic and predictable external influences (seasons for example) as well as to environmental shocks (cold and extreme winds) of more of less knowable frequency and distribution. Self-design to a higher level of organization may be further enhanced by exposure to random of rare perturbations. Unseasonable heat or poisoning are examples of such events.
          The process of self-organization in nature requires periodic as well as random pulses to develop the ability to organize itself against the unexpected and unknown. This may be the mechanism whereby species and bio-geo-chemical diversity is maintained. In designing a waste treatment plant – or space station- capable of responding to unexpected or unknown inputs, the system should be pulsed in relation to light, oxygen, temperature, nutrients, turbulence, exchange rates, and stress inducing compounds. Such pulsing may prove critical in the optimization of Eco-Machines. Again Margalef explains, “One can say that the ecosystem has ‘learned’ the changes in the environment, so that before it takes place, the ecosystem is prepared for it, as it happens with yearly rhythms. Thus the impact of the change, and the new information, are much less.”

6. Cellular Design is the Structural Model
          Design in nature differs from human engineering in a number of fundamental ways. In life the organizing architecture is the cell. When a living system scales up or gets larger it does so by increasing the number of cells. By way of contrast, scaling up in a standard waste treatment facility usually involves installing larger sizes of clarifiers or aerates lagoons, as so forth. With the appropriate structural materials, the ingenuity of the natural world is worthy of imitation. A single living cell is engineered as a whole system, capable of division, replication, nutrition, synthesis of molecular materials, digestion, excretion, and communication with adjacent cells. A cell can undertake specialized functions within an organ or organism. An autonomous system, it is simultaneously interdependent with adjacent cells. Should the ecological engineer mimic such attributes in the design of Ec-Machines, it would lead to an extraordinarily efficient use of energy and materials.
          The microscopic structure of some of the higher plants provides a further model for future design and super-efficient technologies. Strong, cheap, long-lived gossamer films, some with porous membranes to house and support ecological elements, are among the innovations awaited. At the present, cross linkages and cell-like structures are achieved with a series of discrete, rigid tanks or large single structures subdivided by membranes with perforations to direct flows.
          Felix Paturi in Nature, Mother of Innovation: The Engineering of Plant Life argues that current technologies are adapted neither to human needs nor global ecology. Our resource consuming technologies are, in his words, ‘committing suicide.’ He suggests the technological solutions developed by plants over the past 580 million years display a respiratory of wisdom that engineers could follow to develop technologies more closely integrated with the natural world. The place to begin this design revolution is with the living cell.

7. A Law of the Minimum Must be Incorporated
          Ecosystems do not exist in isolation. They are connected to and exchange with other systems through an array of couplings. Neighboring ecosystems mutually define each other. This process extends outward in a lattice-work of interconnections that, ultimately, is planetary in scope. In integrating this principle into the design of Eco-Machine, the question is how many sub-ecosystems will create a viable, self-designing/organizing system that can sustain itself over time measured in years or decades. In Ecological Engineering, Jorgensen and Mitsch recognize the problem and propose a general rule: “Ecosystems are coupled with other ecosystems. This coupling should be maintained wherever possible and ecosystems should not be isolated from their surroundings.”
          Our experience with cross-linking has been confined to three areas of design: a two cell Eco-Machine for the treatment of toxic organic compounds; three cell systems in which we grew fish, their foods, and some edible higher plants; and three and four cell Eco-Machines for teaching ecology in schools. Our experience indicates that an Eco-Machine requires at least three distinct ecological types. One needs to be a soil analog. The other two should be predominantly aquatic. Each subsystem should have unique oxygen, pH, nutrient/ gas cycles and possible light regime. With a minimum of three interconnected cells containing distinct ecosystems, a stable Eco-Machine, will evolve. Even with high nutrient inputs, as in feeding fish in a high-density subsystem, remarkable resilience develops. Single cell Eco-Machines, on the other hand, are very unstable, especially when stressed, and two cells systems require more monitoring and external controls. Many three cell Eco-Machine can be monitored simply by observing the behavior of the organisms, particularly the fish. Control involves such measures as replacing water lost in evapo-transpiration and adjusting inputs.
          More research is needed to determine the minimum number of sub-ecosystems for an Eco-Machine, as well as which subsystems best constitute that number. How widely should the ecosystems differ and how many are needed to maintain a stable system? This will vary with the task assigned the Eco-Machine. When toxins and pathogens can be controlled, the goal is that systems be linked according to function. Waste, food and fuels functions should be integrated. To date out recommendation is a Law of Minimum decrees three, possibly four, distinct ecologies.

8. Microbial Communities Must Be Introduced
          That microbial communities are the foundation of Eco-Machines is very much evident. What is less obvious, if the potential of ecological engineering is to be optimized, is the diversity in communities of microorganisms required. The trend in applied biology is away from diverse microbial communities and ecological concepts and toward those dominated by genetic engineering. In medicine and in environmental remediation the predominant metaphor is the genetically engineered magic bullet that carries out an assigned mission more or less on its own. Contemporary literature, when filled with discoveries of single organisms capable of tackling pollution problems, exemplifies an anti-ecological approach that is probably not sustainable, and at best marginally effective. Ultimately, nature works best through processes of rich symbiotic associations, as yet scarcely understood by contemporary biology.
          In their book, A New Bacteriology, Sonea and Panisset propose a radical new view of life of the role of bacteria. They contend that bacteria are the unheralded organizers of all life on the planet. They further are convinced that the bacteria are organized, not as a distinct species, as is conventionally understood in biology, but as a unitary society of organisms that has no analogous counterparts among other living organisms. From their point of view, bacteria provide, on a planetary scale, the biological bases for cooperation, association and stability. Bacteria, including the photosynthetic species, are the backbone of all Eco-Machines.
          Microbial communities are not comprised exclusively of bacteria. The kingdom Protoctista includes nucleated algae, water molds, slime molds, slime nets, and protozoa, as well as bacteria. They are mostly aquatic. The Protoctista is a huge and poorly understood group of organisms, the majority inhabiting the less studied tropical world. Protoctists are more diverse in life style and nutrition that animals, fungi or plants. Metabolically they are less diverse than bacteria. The role of protozoa in waste treatment has been studied and their significance ascertained. Protozoa have been shown to be responsible for the removal of E. coli and pathogens from sewage.
          Another kingdom of organisms, the Fungi, are also key players in ecological systems. Unlike the Protoctista, they are mostly terrestrial. It is estimated that there are about 100,000 species. Most are microscopic but the kingdom also includes morel, large mushrooms and shelf fungi, most of which are aerobic and heterotrophic. They excrete powerful enzymes and are the toughest of the nucleated or eukaryotic organisms. Fungi can be as efficient as heterotrophic bacteria in the removal of organic matter from wastewater. Their role in the recovery of energy-rich compounds form food processing industries rapidly is becoming appreciated and utilized.
          Microbial diversity is key to the design of Eco-Machines, particularly those handling and processing toxic levels of metals and organic compounds, recalcitrant chemical compounds, and pathogenic organisms, such as cholera bacteria and the hepatitis virus. It is prudent to seed any ecosystems treating wastes with diverse microbial communities, which may be obtained from marine, freshwater, and terrestrial environments. Microbial communities from chemically and thermally stressed environments may prove critical. Ninety per cent of the introduced strains may eventually disappear from a given system, but the remaining ten per cent, coexisting possible for the first time in a unique compositional of species mix, will complete the tasks for which the system was designed.

9. Photosynthetic Foundations are Essential
          Ecological engineering was founded on an appreciation of the ecological importance of plants and photosynthetic activity. This is in dramatic contrast to civil engineering where engineers and plant operators see algae and higher plants in waste treatment systems as nuisance organisms. Considerable chemical and mechanical energy is spent controlling and elimination photosynthetic organisms in the treatment process. Current aquaculture, particularly closed system aquaculture, takes a similar view, shunning algae and higher plants in culture systems. In fish farming, as in waste treatment, chemicals and darkness are used to prevent or inhibit plant growth and photosynthesis.
          However, the use of plants, particularly a diversity of plants, can result in balanced ecosystems that require less energy, aeration, and chemical management. The root zones are superb micro-sites for bacterial communities and increase the available surface area from microbes by several orders of magnitude. Many plants oxygenate waste and water and take up nutrients directly. Some plants sequester metals, occasionally to ore grade. Certain species produce powerful exudates or antibiotics that can kill human pathogens. Although we do not yet know why, we have found that some plants increase microbial nitrification rates. It has been speculated that moss-based aquatic systems, functioning like ecological batteries, will be used to recover materials commercially. Flowers, medical herbs, and trees treat wastes and provide secondary economic benefits as horticultural crops.
          Adey and Loveland argue that an ecologically engineered system without a major photosynthetic component will be out of balance. Without a balanced ecosystems powered by the sun or artificial light, other forms of external energy and materials are necessary to maintain stability in both microcosm and mesocosm. Adey defined the mesocosm as an ecologically engineered system of substantial size – above 5,000 to 10,000 gallons in water volume. A true Eco-Machine requires photosynthetic bacteria and plants representative of each sub group from algae, bryophytes, including the mosses, and the vascular plants, including the conifers, angiosperms or flowering plants. The waste treatment profession tends to select one group, often one species of plant, for purification facilities. Polyculture concepts, however, including algae and various higher plants will be central to the evolution of Eco-Machine.

10. Phylogenetic Diversity Must Be Encouraged
          The regulators, control agents, and internal designers of Eco-Machines are often unusual and unpredictable organisms. Having observed and experimented with ecological microcosms and mesocosms for almost thirty years, we are convinced that there are, among the planetary biota, organisms from every phytogenetic level, which can be used to restore planetary diversity and alleviate the crises of pollution and environmental destruction. The Earth is a vast repository of creatures with which we need to ally ourselves. Discovering and understanding the natural history of such potential allies represents one of the great frontiers remaining in biology.
          H.T. Odum spoke of the need for control species, meaning organisms capable of directing living processes toward a useful end point- potentially foods, fuel, waste recovery or reduction, climate control, and environmental repair. No are in ecological engineering, particularly in the waste treatment fields, has been so badly neglected. The potential biological contributions of other phyla to Eco-Machines are remarkable.
          On a meta-scale, it has been calculated that the participation of animals in the decomposition of organic matter increased processing rates by the significant factor of as much as five. K.A. Voskresensky has demonstrated that banks of marine mussels in the White Sea control the colloidal composition of coastal water sedimentation along the shore limits while simultaneously regulating water circulation within the littoral and intertidal zones. Vertebrates, especially fish, along play key roles in Eco-Machines. Fishes are by far the most numerous and diverse of the vertebrates and in range of diet, behavior, habitat and function, fish are amazingly diverse. In China and other parts of Asia, polycultures of fish have been used to treat waste, including sewage for centuries. The fish species have included filter feeders, herbivores, detrivores, and specialized bottom feeders all of which work together to recycle parent materials completely. Such systems are highly refined and very efficient.
          Phylogenetic diversity is under-utilized in ecological design. The pressure on the ecological engineer favors monocropping and ecosystem simplification and the reason is not to make the system more productive or efficient. It is because simpler systems can be more readily described to environmental regulators. Internal processes are better understood whereas those of an Eco-Machine initially appear diverse and chaotic. In an Eco-Machine containing a number of phylogenetic groups, descriptions of behavior, as distinct from performance, are more problematic. To increase the performance of Eco-Machines by orders of magnitude, a search for appropriate phylogenetic diversity is essential. Greater efforts to preserve planetary biota must be reconsidered in light of this.

11. Sequences and Repeated Seedings are Part of Maintenance
          For an Eco-Machine to be optimally effective, it must be interlinked through gaseous, nutrient, mineral, and biological pathways to the external environment. It should reflect internally the intelligence of the seasons, and should be capable of responding to perturbations and random events. It should contain pathways that originate in varied terrestrial and aquatic ecosystems. Periodic genetic invasions should be orchestrated by the ecological engineer or operator.
          H.T. Odum was among the first to recognize that the ecology of invasions and island biogeography are relevant to the ecological designed. He wrote: “One of the means for developing stable new ecological designs for new environments is multiple seeding; many species are added to the new ambience while conditions are maintained as they are likely to continue…the species go through a self-selection of loops, producing a stable metabolism and complex network within a few weeks.” Expanding on this concept, William Mitch reports, “The multiple seeding of species into ecologically engineered systems in one way to speed the selection process in this self-organization of self-design. 

          The notion that the seedings should be from a variety of ecosystems including the wild, the polluted, the agricultural and those otherwise impacted by human activity has been discussed. In designing a functional ecosystem, these is a further need that consists of imparting the intelligence of seasons to an Eco-Machine. In a natural pond these are seasonally and temperature-based processes that result in changes in community composition on a seasonal basis. To build this into the Eco-Machine requires returning to each of the parent or contributing ecosystems throughout the year for reseeding materials. Organisms difficult to collect in the summer can be captured and introduced into the engineered system in winter.
          There is another approach to connection an Eco-Machine to the natural world beyond the bioshelter or container in which it is housed. An ecologically engineered technology in a bioshelter/greenhouse can be linked hydraulically with a nearby steam, pond, or lake. Small pumps, directly powered by photovoltaic cells or wind engines will circulate water and living materials into the Eco-Machine at low input rates during sunny or windy periods. This fosters seasonal communication, as well as ecological backup should the Eco-Machine be subjected to toxic stress or an interruption in auxiliary aeration. A variation on this would be to link the output end of the Eco-Machine back to the wild system through small volumes of exchange. This domestic Eco-Machine and the wild systems will coevolve to the mutual benefit of both. The mineral, nutrient and microbial diversity of the Eco-Machine, having been draw from many regions and communities, provide beneficial feedback for the wild system that, in turn, could influence the Eco-Machine in its assigned tasks.
          There is yet much to learn about the ecologic of exchange. Ecosystems are constantly seeded by storms, migrating birds and insects, and traveling creatures of all sorts, including humans. The seasonal migrations of birds and some fish affect the transfer of matter throughout the biosphere. Eco-Machines are not strictly closed. Multiple seedings occur naturally and represent a critical element in succession and self-organization or natural and ecological engineered systems.

12. Reflection of the Microcosmos is a Fundamental of Design
          Hermetic tradition has influenced philosophy in both Oriental and Occidental traditions for several thousand years. It has permeated science and human inquiry in China, India, Greece, Egypt, and Europe, particularly during the Renaissance. It is characterized by the investigation of relationships and connections at the most profound level. Beyond cultural variations there have been constants permeating all such enquiries. The term Hermetic refers to Hermes, the Greek god of science, and to Hermes Trismegistus, or thrice great Hermes of Egypt. It’s also used in reference to a sealed vessel or microcosmos reflecting and representing larger realms; the cosmos miniaturized. Illustrations in early texts reveal a surprising resemblance to the physical designs and concepts of the microcosms Odum and his associates used in the 1960s to investigate the forest floor in a tropical rainforest before and after it was intentionally subjected to radiation.
          The concept of the microcosmos most relevant to the evolution of Eco-Machines lies in the Hermetic epigram “as above, so below.” For purposes of ecological design, the miniaturization of nature –not the relation to the pieces but the scale- should echo the fundamental patterns of he macrocosm. The Earth and its atmosphere, its relationship to the sun, moon, and the other planets are relevant to the design of the Eco-Machine if it is to be a true microcosm.
          We designed our first microcosm, a bioshelter for food production in the early 1970s. Reflecting the relationship of the planetary oceans to the landmasses, we gave over 70 percent of the interior space to water. The remainder was terrestrial. The appropriate interior volume of contained atmosphere was designed to provide an internal hydraulic cycle and climate regulation. We engineered simulated currents and upwellings in the aquatic zones as well as transfers between the subsystems. Although the early microcosms were crude, they functioned well and produced foods. In subsequent years we transferred the ocean equivalent from sub-surface ponds to tall transparent cylinders. This further led us to develop an effective solar aquaculture system, which was tightly integrated with the terrestrial food culture. Through our various experiments we found that whenever we violated basic Gaian or global relationships it was necessary to add artificial inputs of energy, chemicals, and materials in order to stabilize the systems.

          Despite concepts of holism and harmony in ecological engineering highly developed in China, as reflected in the contemporary work of Yan and Ma and Chinese success in food production and environmental protection technologies, the concept of microcosm remains underutilized in the design of Eco-Machine for waste treatment in both East and West. The best of them, complete with feedback loops and multiple ecosystems, are essentially linear and, as such, not optimally evolved. It could be that Eco-Machines for waste treatment should not be isolated entities but should be integrated with food production, fuel generation, climate regulation, housing and manufacturing to creating whole systems that are mirror images of the great cycles, which sustain all life.
          As the millennium approaches, the human community finds itself at a turning point. The twentieth century has been the emergence of high rate computation and electronics, shortly followed by their miniaturization. The century has also seen the biological and ecological sciences emerge as disciples of complexity, exchange, symbiosis, and dynamic states. The future lies in the miniaturization of nature and the building of living technologies. The goal should be for human populations to support themselves without destroying the wild systems that are the mother to human ingenuity. This represents a radical restructuring of society. It includes a partnership between humanity and nature, in which we become stewards of the living systems that sustain us but which, in ultimate terms, are beyond our knowing or controlling.