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Vital Energy
 
by Sam Gamble
 

Marine aquarium's purpose is to allow us to see, understand, interact. and enjoy what has mystified man as the possible origin of our existence. The life that goes on in the water environment has drawn the curiosity and attention of almost all that come in contact with it. For reasons of curiosity, esthetics, and learning there has been a long history of efforts to reproduce what mother nature has already provided so exquisitely. For the most part we have made a lesser copy. We are gaining knowledge and creditability, to close the gap. Recently natural systems have achieved greater success, with greater diversity than ever before. This has been the result of less gadgetry and more application of ecological principles. Concepts that have stood in the wings, admittedly too long. For the first time we are able to easily and successfully maintain some of the oceans' most delicate and beautiful creatures. We are beginning to realize the role of energy as being other than just light and heat. It's much more than that.

 
For understanding some of the basis and origins for the concept for vital and synergistic energy cycling, we need definitions. In doing so there will be better understanding. Since we are most familiar with the nitrogen cycle, it's a good starting point.
 
The nitrogen cycle has been the important emphasis for closed systems for many years. However, carbon is the demandingly critical element for life. For survival of the living environment it is important to cycle or remove wastes and nutrients containing nitrogen compounds. But, we must not forget that both carbon and nitrogen energy cycles are tightly and concomitantly related by the pathways they follow.
 
With millions of years of application and modification, naturally occurring systems have become very successful and proficient using specialized methods. In the last few decades, we have begun to understand and apply at least enough to satisfy our desire to keep aquatic-marine organisms in artificial environments. We construct them with as many natural components we can understand and use. We have ironically created maintenance in the process, by overlooking important interrelationships. Concentration on the mechanics of the interrelationships will reduce the need for maintenance.
 
Early on we discovered ways to reduce toxic wastes containing nitrogen. Particularly ammonia and nitrite. Filters and filtering systems were born. The concept was neatly explained by the nitrogen cycle. At first nitrate was considered the end of the road and "okay" because it wasn't thought to be directly toxic unless accumulating in very high concentrations. It wasn't until less tolerant species were desired that methods to remove nitrate were sought. Keeping cnidarians was key to the evolution of our focus beyond the overemphasized nitrogen cycle.
 
Natural nitrate reduction can be thought of as the start of a new conceptual trend in aquarium systems. Basically all it involves is providing an environment for bacteria to metabolize nitrate to gain the oxygen it contains. To do so, the bacteria's environment requires reduced oxygen, so the oxygen in a nitrate molecule becomes desirable electrons. This is a destructive process for the NO3 molecule. The other route for nitrate is to assimilate it back to ammonia. The first is more desirable in our reef systems and the second is desirable by nuisance algae. However, nitrification must not be eliminated to preserve balance.
Nitrate is not a "thing", but rather only a chemical fragment or constituent of foodstuffs for cells. Living cells have the arduous task of transformation of chemical compounds so as to use what they need, in the form that they can use. How nitrate is used requires energy transformation, which means manipulation of chemical bonds, like oxygen, because of the energy contained by them.
 
The fate of nitrogen in the nitrate molecule is only a small part of the cycle, and it's associated with carbon by the needs of microbes. The carbon and nitrogen cycles are of fundamental importance and inextricably linked to marine microbial production, mineralization, and sedimentation processes. Importantly, those macromolecules mediating biochemical transformations (protein - enzymes) and physiological regulatory, or genetic controls (hormones, growth regulators, DNA,RNA), show a common reliance on specific ratios and configurations of carbon and nitrogen. It is then not surprising that nitrogen and carbon limitations of microbial metabolic activity and growth have important consequences for production and mineralization of organic matter in a marine environment.
 
Given the close coupling of carbon and nitrogen cycling in marine production and mineralization processes, it seems intuitively obvious that our alteration of and interference with, natural cycling of these elements has and will continue to produce significant impact on marine fertility and resultant water quality.
The energy transformations are step wise processes controlled by the cell and the environment it produces. In many instances an unbalanced aquarium or an improper environment, upsets the natural balances of energy cycling and produces the need for external filtration to remove elements not used. The desired pattern of transformations has been changed. Synergistic equilibrium has been partially destroyed or damaged.
 
Because of our familiarity, this concept can be focused toward what nitrate means, as a nutrient, by what physical pathway it must follow to be used by the living cell (microbial mediator). Also, directing the understanding that it is metabolism (chemical transformations) adaptively breaking down or synthesizing that ultimately causes pollutants to stay at proper levels. It all adds to the scope of the picture for benthic ecology and "biogeochemical pathways" that our new reef aquarium approaches rely on.
 
Our recent trend in aquarium filtration is using sand beds specifically constructed to provide environments for increased natural microbial mediation. The sand bed system's goal is to properly maintain as many compounds and elements as possible at natural and desirable levels. The idea brings our attention back to the cell and its activities within specialized environments. Our ability to use microbial populations of cells stems from what we measure as ecological variables, i.e. physical and chemical factors and the properties of the microbial populations themselves, such as their distribution, densities, metabolic requirements, and activities.
 
A gradient zone in our aquarium's ecosystems like the sediment - water interface, is a crucial site of microbial activity coupled to biogeochemical cycles. The microbial species vary greatly, each selected to perform its specialized function.. The cells involved, can be compared to a tiny biochemistry laboratory, dedicated to breaking down &/or synthesizing numerous substances. The tools used in the energy transformations are all at the molecular level. In fact, they are the so-called enzymes.
 
The enzymes are not randomly distributed within the cell. The cell is a highly organized structure and cannot be considered as just a bag of enzymes. The cell is responsible for a multienzyme system derived from many of its specialized organoids, disposing of compounds and elements in an orderly fashion within the macromolecular framework. A very deliberate mechanism for metabolism.
 
Metabolism can be defined as a sum of the chemical transformations in the cell. It includes both the breakdown &/or rebuilding processes. In regards to energy, some is used and some is liberated. This is important, because without cell metabolism, energy may follow undesired routes or remain stored as an unusable form. For example, the different substances taken by the cell as foodstuffs, such as glucose, amino acids, and lipids can be broken down into smaller molecules with the liberation of energy. The energy in turn is utilized by the cell in the synthesis of new and more complex molecules.
 
When not given the opportunity to be used effectively, synthesis and utilization won't happen if usable molecules are stored or removed. The various energy pathways act to achieve the processes for stabilizing some of the aerobic and anaerobic functions for energy cycling using enzymatic activated biologic catalysts. These processes work together through the nitrogen cycle and carbonization cycle. It results in the decomposition and use of organic material, causing certain organisms to out compete others for better equilibrium because they have access to needed materials.
 
Enzymes, as biologic catalysts, accelerate chemical reactions of the cell. They facilitate transitional reations seeking "equilibrium" to the dominant environmental ecosystem. When operating properly the multienzyme system creates and maintains energy and prospective cycles.
 
The essential source of energy in living organisms comes from the sun. The energy arrives by units of light and is trapped by the pigment chlorophyll. Chlorophyll is present in the cells of green plants, and accumulates as chemical energy within the different foodstuffs. Without the sun, there would be no life on this planet.
 
There are two main classes that all cells and organisms can be grouped into. Their difference stems from the mechanism used to extract energy for their own metabolism; 1. autotrophs, 2. heterotrophs. With autotrophs (i.e. green plants) CO2 and H20 are transformed by the process of photosynthesis into the basic sugar compound glucose, from which the more complex molecules are made. Heterotrophic cells (i.e. animal cells) obtain energy from different foodstuffs (i.e. carbohydrates, fats, and proteins), that were synthesized by autotrophic organisms.
 
The energy held by these organic molecules is released mostly by combustion (oxidation) with O2 from its surroundings. The process is also called aerobic respiration. The release of H2O and CO2 by heterotrophic organisms completes this cycle of energy.
 
Must note, plant cells can also derive energy by respiration of the foodstuffs that were synthesized in their own chloroplasts. So then it is possible for both autotrophic and heterotrophic processes to occur in plant cells.
 
Also, there is a small and important group of bacteria that is capable of obtaining energy from inorganic molecules. The process is called chemosynthesis. As an example, Nitrobacter oxidizes nitrites to nitrates, and others transfer ferrous into ferric oxides, and some SH2 to sulfate.
 
Obtaining and using energy other than radiant (light) requires energy transformations locked within chemical or potential energy of foodstuffs by different covalent bonds between the atoms of a molecule. Inside the living cell this enormous amount of energy is not released suddenly as in the combustion (oxidation) in a flame. Instead it proceeds in a step wise and controlled manner, requiring and using dozens of oxidative enzymes that finally convert the fuel into CO2 and H2O, liberating energy.
 
There are many processes produced in the living cell by which organic substances are oxidized and chemical energy is released. All these processes are categorized by the function of cell respiration. There are two types of cell respiration. These are; aerobic respiration, where complex molecules can be degraded with the participation of molecular oxygen; anaerobic respiration, where degraded molecules occur without the participation of molecular oxygen. Anaerobic respiration is also sometimes termed, fermentation. As mentioned before, it is important to include both processes for balanced energy cycling in marine ecosystems like our aquariums.
 
From the hierarchy of organisms and their phylogenic order, the lowest forms of life get their energy by anaerobic fermentation. Higher forms of organisms get more energy from aerobic oxidative phosphorylation, and in the highest organisms this is proceeded by fermentation and coupled to it. The first case gives the lowest supply of energy, the second is intermediary, and the third is most efficient.
Applied to sand bed filtration, sedimenting organic particles are transformed, helping to create the anoxic interface and adjacent sediments to produce organic compounds of lower molecular weight. These small molecules are utilized by different bacterial groups with sequentially NO3, MnO2, FeOH, SO4, and CO2 as terminal electron acceptors. The sequence, for example, is equal to nitrogen fixing algae having an adaptive edge, anoxic organisms are the hard working intermediaries and anaerobic organisms form the base of the energy pyramid using CO2 by fermentation and yielding the least energy.
 
To supply the intermediary microbial populations with an abundance of oxidizing enzymes is a method to enhance useful energy cycles and shunt some of the adaptive autotrophs. It would favor facultative metabolism, thereby decrease some of the need for anaerobic respiration. Another alternative would be to extend the anoxic interface (intermediaries) and provide a storage and work place like in a plenum, for surplus nutrients . Doing both would be optimum and an example of synergy on a new scale.
 
The creation of the "optimal ecological environment" would allow reproduction of many of nature's secrets. We have made some advancements recently. But, until we can accurately and consistently cycle all the compounds and elements we put into our aquariums to result in useful energy, we have to keep searching. Biological filtration, natural systems, and sand bed systems have been important mile stones on the road to in situ aquarium science; the future.
 
The acceptance, understanding, and enhancement of the essential energy cycles will stabilize the microorganisms that form the inextricable foundation that will produce in situ filtration. The bottom line is the equilibria of shared energy.
 
Discussion & questions:
102170.3150@compuserve.com
 

 

Biography :
 
Sam GAMBLE has a B.S. degree in Marine Science (Biology). He has spent over five years in marine aquaculture growing penneid shrimp, Artemia, and many kinds of algae. For ten years his experience has included maintaining over 30,000 gallons of marine aquarium exhibits at John Pennekamp Coral Reef State Park. Recently his time has been devoted to research and developpement of products for aquariums made for natural systems like sand beds. Since 1991 he has published over 20 articles about aquarium subjects for magazines and news letters, which includes a monthly column on the Internet.
 
 
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