Coral Reef Magazine Volume 3

by Coral_Reef_Magazine Thu 21 May 2015, 20:07

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Coral Reef Magazine Volume 3
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Page 1
ACTIVATED CARBON FOR MARINE AQUARIUMS – Part 3

Page 2
THE PH VALUE IN MARINE AQUARIUM

Page 3
Measuring pH values in the marine aquarium

Page 4
THE CARBONATE HARDNESS IN SALTWATER – PART 1

Page 5
THE CARBONATE HARDNESS IN SALTWATER – PART 2

Page 6
KALKWASSER (Limewater) AND ITS AUTOMATION IN THE MARINE AQUARIUM

Page 7
TRACE ELEMENTS IN THE MARINE AQUARIUM – Part 1

Page 8
TRACE ELEMENTS IN THE MARINE AQUARIUM – Part 2

Page 9
NUTRIENTS PART 1: THE NATURAL ENVIRONMENT

Page 10
NUTRIENTS PART 2: WHAT ARE THEY?

by Coral_Reef_Magazine Thu 21 May 2015, 20:09

ACTIVATED CARBON FOR MARINE AQUARIUMS – Part 3

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What is the correct use of activated carbon?

(Part 2)

4 Elimination of yellowing and medicinal substances

The most common use of activated carbon is for the elimination of undesired substances from the aquarium’s water. The problem, unfortunately, is that the carbon does not differentiate between desired and undesired substances. In this way, some important elements like iodine are systematically eliminated from the water. Therefore, this is the only valid rule: just use activated carbon in reef aquariums in case of necessity, and especially in the right doses! It is usually placed in the filtering system in bags made specifically for this material. The period of contact does not have an important role, as the water flows quickly around it. The recommended quantities are from about 0,5 up to 1 litre of activated carbon for 500 litres of aquarium water. After one, three days maximum, the activated carbon has to be removed from the water. Long life carbon does not exist! The absorbing surface of the material is quickly saturated by the substances contained in marine water, and then it cannot absorb any more. Once the free surface is filled, the process stops and the exchange begins. The previously absorbed substances are put back in the water and they are replaced by more easily absorbed ones (iodine, for example). After using activated carbon it is essential to dose trace elements again, in particular large quantities of iodine should be re-introduced. The use of this filtering material is however always advisable in case medicinal substances were introduced, in circumstances where it is possible that the fish have been poisoned (heavy breathing), or if the water quality has substantially worsened (yellowing substances). These three situations are the most typical to justify the introduction of such a material into the filtration system. A careless use of activated carbon in reef aquariums is therefore heavily advised against.

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5 Biological filtration of the water

Another field of use for activated carbon is biological filtration of water (bacterial colonization). Because of its good absorbing ability, carbon offers to the bacteria that colonize it large quantities of organic substances. The organisms that develop in it (there can also be other unicellular organisms) are benefited by this abundance of nutrients (Reimann 1969). However, not all of the carbon’s surface is made available. The most internal part, in fact, cannot be occupied because of the size of the bacteria themselves, about 1-10 nm. The incredibly small macro-pores (25nm), mesopores (1-25 nm) and micro-pores (0,4-1 nm), that can absorb organic substances, are not reachable by the bacteria. Many aquarists are convinced that active carbon can offer a huge colonisable surface to bacteria. In practice, it has been observed that this belief is not true, and that many other filtering materials are able to offer substantially better performance. However, thanks to its absorbing ability, carbon has a strong attractive force on bacteria. The absorbed substances are processed by the bacteria; in this way the surface is partially cleaned and made suitable again for a new process of absorption. Despite everything, the use of a biological carbon filter is not recommended in a reef aquarium, because of its tendency to absorb trace elements, its predisposition to be obstructed quickly and the resulting lowering of Redox potential. Such an aquarium normally offers enough colonisable surfaces (living rock, flooring). In aquariums of only fish, instead, or in other special tanks (for example mangrove aquariums), the use of activated carbon can still present a valid alternative. Based on the organic matter content, the recommended dose for about 100 litres of water is 1-2 litres of activated carbon. Every two to six months it is opportune to replace a third of the material with some new one. If used in very slow circulation, a carbon filter is also capable to eliminate nitrates. Anaerobic bacteria take advantage of the lack of oxygen, colonizing the more hidden parts of the carbon. This effect, however, is attributable only to the bacteria; carbon itself is not able to absorb nitrates! This assertion too can often be found in books.

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Page 1

by Coral_Reef_Magazine Thu 21 May 2015, 20:14

THE PH VALUE IN MARINE AQUARIUM

[You must be registered and logged in to see this image.]The pH value tells us about acidic and alkaline processes that take place in liquids. It is a very important information for the keeping of an aquarium, as variations in this value can bring drastic changes to the environment of our animals. Acidic substances reduce the pH value and alkaline ones increase it. Measuring is done on a scale that goes from 0 (acidic) to 14 (basic). The value at the middle of the scale, 7.0, indicates neutrality between acidic and basic. If, for example, today we measure a pH value of 7.5 in our aquarium, while yesterday we measured 8.5, it means that the water in our aquarium is ten times more acidic than it was before. In this case, scientists talk about “logarithmic negative decay”

What modifies the pH value?

Every acidic substance that ends up in our aquarium, or that develops in it, reduces the value of pH. In the same way, every alkaline substance increases it. Even in a reef aquarium that works harmoniously the pH value changes over time. Normally, it is especially low in the morning and it increases during the day, to then decrease again during the night. These changes happen mainly because of differences in the content of carbon dioxide in the water. Animal breathing and plant activity, algae in a marine aquarium for example, generate CO2, reducing the pH. The photosynthesis that happens during the day consumes large quantities of CO2, causing the acid content in the water to decrease, and the pH value to increase. Towards the end of daylight hours, values of 8.4 or 8.5 are normal. At night, however, the plants stop absorbing carbon dioxide, and the CO2 that is created stays in the water. And now, the crucial question: how much alkaline substance, which tends to bond with CO2 and neutralize it, or absorb it, is there in the water? In this regard, we must take in consideration carbonates, which we can measure by their carbonate hardness.

With high carbonate hardness, which means relatively hard water, for example at 7,0° dKH, our aquarium will be able to absorb CO2 until the next morning, without decreasing in pH and entering the danger zone below 7.8. However, if our carbonate hardness is around values of 1° or 2° dKH (very soft water), it means that we do not have a large alkaline reserve available to work as a buffer, and we risk that the pH value will collapse to low levels during the night. Especially if we consider that even during bacterial activity for the transformation of organic matter, for example of leftover food or the excrement of the aquarium’s inhabitants, acidic metabolism products are created, which influence the acidity of the water, it becomes clear how important it is to have an adequate reserve of alkaline buffer. Stabilising the pH value In order to stabilise the pH value in an aquarium, as in reducing daily fluctuations, we have to maintain a sufficiently high reserve of alkaline buffer.

This can be obtained with, for example, a partial substitution of water done regularly, about ten percent every month. Another possibility is adding an appropriate buffer of carbonate hardness. In this way, we provide alkaline substances that neutralise the acidic ones, stabilising the pH value. If we replace the water that has evaporated with tap water, we still add carbonates, and of course a calcium reactor can help increasing the carbonate hardness of our aquarium. All these solutions go towards increasing the carbonate content of the water of the aquarium, but in this way they also indirectly stabilise the value of the pH.

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Page 2

by Coral_Reef_Magazine Thu 21 May 2015, 20:17

Measuring pH values in the marine aquarium

[You must be registered and logged in to see this image.]To determine the environmental conditions of an aquarium, we need a reliable pH measurement. This should also be performed regularly, for example once a week. It is appropriate to carry out the measurement always at the same time of day, to be able to really see the normal pH variations that take place during the day. You should keep in mind that if you want to carry out an exact measurement of the pH, you must use the water sample immediately. During transport, for example to take it to an aquariology shop, the pH value might be altered.

Testing with drops

For the beginner marine aquarist, a common test using readily available drops is sufficient as it is quite accurate. To do the test, a few drops of the solution are introduced in a few milliliters of aquarium water, and then the resulting colour is compared with a colour chart. Your shop keeper can recommend an appropriate test, and the instructions for use are available on the box or in a leaflet contained in it. Before buying, however, check the colour chart, to make sure it matches your expectations. For measuring in sea water you will need a precise result in the range between 7.5 and 8.7. Be careful also to check that the test is not too old (expiry date), and of course that it is suitable for use with sea water.

Electronic meter

Those who want more precise information, with decimal numbers, can use an electronic meter. However, this device must be calibrated very precisely for it to provide exact measurements. A pH meter device is certainly better than drops, but in case of erroneous calibration it can become even dangerous, because by indicating the wrong value it can mislead the aquarist. The same, however, can be also said of a measuring solution that is too old, which most probably does not work correctly anymore. Therefore, do not blindly trust the measurement if you get abnormal results but everything in your aquarium seems to be in order.

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Page 3

by Coral_Reef_Magazine Thu 21 May 2015, 20:19

THE CARBONATE HARDNESS IN SALTWATER – PART 1

[You must be registered and logged in to see this image.]The carbonate hardness (abbreviation KH) is one of the most important parameters in a marine aquarium. The aquarist should regularly measure this value, because in a well-functioning biotope marine, the need for carbonates is enormous. The carbonate hardness can decrease by 5-10 ° in a matter of only days.

The hard corals like Acropora spp. need not only calcium but also carbonates.

What is the carbonate hardness?

The carbonate hardness in the world of marine aquariology, defines the ability to stabilize the pH value of the water. All common tests used in aquariums measure only the buffer substance present. This common definition in our environment does not have much to do with the carbonate hardness as it is conceived in other areas. Unfortunately this fact is described only in a few aquarium books, and the definitions are sometimes expressed in a contrasting manner. The best definitions for “carbonate hardness” are: “ability to bind acids,” acid capacity pH 4.3 “or” buffering capacity “. But for easier understanding, although the term is not quite correct, we will continue to use the term “carbonate hardness” in the article. We will also use, for simplicity, also the old definition of degrees: ° dKH = German degrees of carbonate hardness. A buffer system consists of at least two components, a weak acid and a corresponding salt. What is essential in a buffer system is its effect on neutralizing acids. If a liquid possesses such a characteristic, its pH value will vary and become weaker when an acid is added, than it would in the absence of this capacity. If you add an acidic substance, like the products to metabolize the water of an aquarium, the salt can bind with these neutralizing substances. The “carbonate hardness” in the aquarium consists mainly of the buffer system carbon dioxide-carbonic acid – hydrogen carbonate-carbonate. Systems such as phosphoric acid-phosphate hydrogen phosphate play a limited role.

The higher the value of the carbonates, the less the pH value will be affected by acidic substances. The carbonate hardness stabilizes the pH value of the aquarium

What is the carbonate hardness in seawater?

In a marine aquarium the carbonate hardness has two basic tasks:

Stabilization of the pH value

As already mentioned, the carbonate hardness is characterized by a buffer system. In a marine aquarium it should never fall below 5 ° dKH. Below this value the fluctuations of pH in the aquarium water, are so huge that the animals can suffer serious consequences. If the value of the carbonate hardness should become around 2 ° dKH, the pH value of a reef, in the course of the day, will fluctuate well outside the normal limits (7.9 to 8.4). For animals, a variation of only one point, for example from pH 8.5 to pH 7.5, signifies a change in the level of acidity in the water by 10 times, with a two point change that changes to 100 times. The acidity causes a lot of damage to the fish gills and also to the delicate tissue of the coral polyps, which in nature are obviously never subjected to such changes. As a precaution the aquarist should never let the value of the carbonates go below 7 °. To maintain a stable condition in the aquarium, it has been proved that a good value of carbonates is around 10 °. Natural sea water, however, often shows values of only 7 ° dKH, but in a limited environment such as that of an aquarium, the acidic substances derived from animal metabolism cause a much higher concentration, which must obviously be corrected. In addition the photosynthetic activity of symbiotic algae affects the pH of the aquarium, because of the limited amount of water, in a much more obvious way than if in the sea. For these reasons, the carbonate hardness of an aquarium should always be higher than that measured in nature.

Supply of calcium to consumer animals and algae

Many marine animals need, for the construction of their skeletons, dissolved calcium, especially hard corals and clams, which incorporate large amounts of this substance. Even the calcareous algae, such as the reddish Mesophyllum species that develop as a crust, or the green ones from the species Halimeda, extract a lot of calcium from the water. This important substance is characterized by two components: calcium and carbonate. If one, or both components are missing symptoms of deficiency occur. Especially for small polyp stony corals, the lack of calcium causes a rapid block in development.

A Carbonate hardness value of more than 15 ° dKH provides no advantage and should be avoided, because it may indicate precipitation phenomena. The consequence is that some substances, important for the development of the animals, would be lost by binding to each other.

Texts by Burkhard Ramsch and Beate R. Sellner

Biologists Company AquaCare, Herten, Germany.

Photo: D. Knop

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Page 4

by Coral_Reef_Magazine Thu 21 May 2015, 20:23

THE CARBONATE HARDNESS IN SALTWATER – PART 2

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Increasing the carbonate hardness of the aquarium

The few lucky aquarists that have tap water free of harmful substances but rich in carbonates simply add those by replacing daily the water that evaporates. This operation, when possible, is only sufficient if there are only a few species that consume the calcium in the tank. In the case of an aquarium with a lot of corals, especially hard ones, the need for carbonates is so high that it cannot be replaced in this way. In recent years four systems have proved to introduce a sufficient amount of carbonates to the water.

Kalkwasser (Limewater)

The method of calcium hydroxide does not produce any practical carbonate to the aquarium. The hardness of the water is indirectly produced from the highest value of PH in the aquarium, where the carbon dioxide from the air above penetrates in the water (surface skimmer) forming the carbonate hardness. The high PH of hard water makes a very slow dosage recommendable. To measure the calcium and for the effect of the precipitation of phosphates this method is more than suitable.

Adding generators of carbonates

With this method you add carbonates to the aquarium using chemicals (powder or liquid). These are contained in the so called correcting salts. The aquarist should pay attention to which substances he chooses to use and keep in mind that for a marine aquarium; only those that have a pH 8 or higher are suitable (test the powder first by dissolving in water. Products with an acidity level under PH 8 should not be used. The advantage of this method is that its rapid and simple to use, the disadvantages are the costs and the continuous need to keep the doses under control, its ionic imbalance which is unavoidable even while continually changing the water and the values when reached are relatively modest.

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Injection of carbon dioxide

This technique, which is very common in the American area, provides the aquarium with carbonates in the form of carbon dioxide, which in part transforms into carbonates. If hard water is used, and basic safety standards are applied (controlling the pH, which if too low blocks the entry of CO2 by closing the magnetic valve), this method can work and lead to the strengthening of the coral growth (BROCKMANN, 1999). This system should only be used, however, in aquariums with a very low concentration of nitrates and phosphates otherwise you can create problems with unwanted algae. Management costs are medium-high (refilling CO2 cylinder); purchasing costs are also similar (CO2 cylinder, pressure regulator, needle valve and pH regulator).

The Calcium Reactor

This newest accessory, very fashionable, expands the use of the technique of injecting carbon dioxide. The water is enriched and therefore with a much lower pH value, it reacts in a container of calcareous material. This melts slowly, adding calcium carbonates to the water in the aquarium. The advantage is its high efficiency, its disadvantages are the high purchasing costs (calcium reactor + earlier components) and the risk of algae problems. In aquariums with high values of nitrates and phosphates, there is often, after the installation of the calcium reactor, an exaggerated growth of annoying green algae. Recommendations, such as to insert the water outlet of the reactor directly into the skimmer (it is always of pH values from 6.0 to 6.05), don’t lead to much, since when using this system only a part of the excess carbon dioxide is removed. There have been nevertheless for sometime new types of calcium reactors whose output of water is characterized by pH values much higher, the risk of algae while using these new types of machines is much lower.

How do you measure the carbonate hardness

Titration tests, commercially available for carbonate hardness normally provide satisfactory measurements. In contrast to other tests (pH, nitrates etc.) they remain stable and their accuracy is more than sufficient for a normal aquarium. We need to however always consider their margin of error which is between 1 and 2° dKH. It is advisable to pay attention to certain factors:

Never perform an analysis of turbid water, this can significantly distort the results by raising the values. You must wait until all the sediments are deposited and focus the analysis only on the clear water drawn from the container.

Never perform the test if the water is at a high temperature or if it has a high pH value. The tests work better if there are normal conditions for an aquarium (25°C, pH 6- Cool

. Keep the tests in a dark place. Close the tests immediately after use to avoid contamination. Always follow the instructions carefully.

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by Coral_Reef_Magazine Thu 21 May 2015, 20:27

KALKWASSER (Limewater) AND ITS AUTOMATION IN THE MARINE AQUARIUM

[You must be registered and logged in to see this image.]Are you tired of stirring to prepare limewater with calcium hydroxide? Of handling tanks, buckets and tubes? Then you are ready for the mixing cylinder. This device is composed of a tank for the hydroxide as well as a container for sediment and it is located in the aquarium.

The water is provided through a system of inverse osmosis, and it is made to slowly go through the tank full of hydroxide. On the top, there is the sediment container water, where the deposit in suspension is accumulated so that we obtain a clear solution of limewater. The cap prevents it from coming into contact with the outside air (CO2), and through the draining tube the calcareous liquid drips toward the aquarium. It is recommended to mix the hydroxide in the tank with a stick, and to replace it about every two days.Are you tired of stirring to prepare hard water with calcium hydroxide?? Of handling tanks, buckets and tubes? Then you are ready for the mixing cylinder. This device is composed of a tank for the hydroxide as well as a container for sediment and it is located in the aquarium.

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Automating the hard water mixing cylinder

If you want to automate your hard water mixing cylinder by connecting it with an inverse osmosis system, here is our advice: use a level sensor placed in the aquarium (floating), which activates a magnetic valve, to avoid filling the tank excessively. Check the water dosage through a pH test (second magnetic valve), to avoid going over the maximum preset value. The hard water can flow to the aquarium only when both the magnetic valves are open. The important thing is to install the the two valves between the water net and the membrane, to avoid them being under water pressure when they are closed. With a timer controlling the floating water level sensor, it is possible to set the time when the dosing of hard water has to happen. Dosing the water in the morning, when the pH of the aquarium is at its minimum, is particularly favourable.

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Page 6

by Coral_Reef_Magazine Thu 21 May 2015, 20:32

TRACE ELEMENTS IN THE MARINE AQUARIUM – Part 1

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What are trace elements?

Trace elements are mineral substances that are present in nature, and that, unlike macro elements, are eaten by organisms, because of their important metabolic vital functions. For a substance to be considered a trace element, the needed daily dose should be up to 50 mg per kilogram of body weight: if the needed dose of a substance is below this limit, it is considered a trace element.

The essential trace elements, whose functions are usually known, are: arsenic, chromium,iron, fluorine, iodine, cobalt, copper, manganese, molybdenum, selenium, vanadium, zincand tin. They are important components of hormones, enzymes or vitamins, or they have a catalysing coenzymatic effect on certain metabolic functions. If they are missing, there will be a malfunction of the metabolic processes or other functions.

Some of the non-essential trace elements are aluminium, barium, bismuth, boron, bromine,germanium, lithium, nickel, mercury, rubidium, silicon, strontium, tellurium, titanium andtungsten. Science is still debating what their function is, but that does not mean that they are not important for the metabolism of living organisms. Often it is just the chance of recognizing or testing their function that is missing. Strontium is a good example in relation to corals.

The elements that are necessary in higher quantities are sodium, magnesium, barium,calcium, phosphorus, sulphur and chlorine. They are important for several specific functions, such as the content of water or the acid-basic balance of an organism (sodium, chlorine).

Manganese and iron, for example, play a role in the action of a specific enzyme that helps corals to limit excess oxygen and the effects related to it. This is necessary for detoxing from harmful oxygen radicals. If manganese and iron were missing, problems caused by the excessive oxygen saturation in the tissues might appear in corals, quickly turning them white (Expulsion of the symbiotic algae) even in normal temperature and lighting.

Part 2 will follow

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by Coral_Reef_Magazine Thu 21 May 2015, 20:35

TRACE ELEMENTS IN THE MARINE AQUARIUM – Part 2

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Why do organisms need trace elements?

This question is relatively easy to answer. Life originates from the sea. This means that the metabolic processes of all organisms, even of those that nowadays live on the ground, have developed in the ocean. Even us humans have inherited in our bodies a small ocean of some kind: the about 4 or 5 litres of blood that circulate in our body, since it is a liquid that in its saline content resembles that of sea water, and in which there are several trace elements in the needed vital concentration. If there is a shortage of a certain trace element, symptoms of illness appear. Something similar happens in our aquarium animals, whose health depends on the provision of trace elements from the sea water around them.

Metabolic processes are nothing more than a biochemical reaction, and in sea water there are dissolved all the mineral substances available on earth, because water permeates the ground, and then takes the substances to the ocean. In this way, in the course of millions of years, were developed all those biochemical processes that corals need to grow and procreate. Therefore, if there is a shortage of mineral substances these processes stop forcedly, creating dysfunctions in the metabolic processes, and the corals get sick. Growth slows down, parasites are able to settle on the tissues, or the coral whitens.

A shortage of trace elements in an aquarium can develop in several ways:

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[*]because of natural consumption (animals or plants eating the substances),

[*]because of precipitation (the transformation of substances dissolved in water into insoluble compounds, which are not available for organisms anymore),

[*]because of the exportation of water (filtration on activated carbon, protein skimming, reverse osmosis). It is therefore impossible to neglect to regularly add these substances.

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Adding trace elements

The easiest way to dose trace elements in an aquarium is to make regular partial changes of water. If the partial changes are made appropriately, you will be correctly managing a nice reef aquarium, inducing a magnificent growth in the hard corals, as demonstrated in the column “Aquarium portraits” by Petra Barg (2004), who does a monthly change of about 40% of water (if you subtract the volume of the ornamental rocks from the content of the aquarium it is almost 50%). Anyway, to quote the old saying, “all roads lead to Rome”, even in reef aquariology. Many aquarists obtain great results by doing moderate partial changes of water (for example 10% every month) and adding trace elements. Especially in aquariums where there are only a few small fish, abundant partial changes of water are not as essential as in densely populated tanks in which big fish with a high metabolism swim, which naturally also produce many nutritious organic substances (nitrate ions, phosphate ions) as waste products. If there is not that much pollution of nitrates and phosphates in your aquarium, instead of abundant changes of water it is possible to do smaller changes (10% per moth), but you will have to regularly add trace elements. This is because it is not necessary to reduce the concentration of these nutrient substances through water substitutions.

To add trace elements it is definitely not necessary to use dosing pumps. They make dosing the trace elements easier and convenient, that is for sure. But adding them manually also works well, as proven by many beautiful aquariums. It is however important to use high quality products, and to not assume that “the more the better,” and use larger quantities than the ones indicated on the maker’s instructions or what the aquarium really needs. We should always remember that these substances in very small quantities are of vital importance (from which the name of “trace elements”), but in high concentration they can be toxic, like copper, nickel, and zinc.

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by Coral_Reef_Magazine Thu 21 May 2015, 20:38

NUTRIENTS PART 1: THE NATURAL ENVIRONMENT

[You must be registered and logged in to see this image.]30 years ago, nutrients in marine water were under the spotlight, because they accumulated in high concentrations causing the flourishing of algae that overwhelmed and damaged corals. When the use of the protein skimmer was introduced and popularized among aquarists, and when this incredible filtering method was used in combination with limewater, it became possible for the first time to keep the concentration of nutrients in aquariums under control. This was one of the main innovations that made the creation of miniature reefs possible. Today there are signs that make it is possible to speculate that many reef aquariums suffer from a lack of nutrients.

Are these substances responsible for a new problem?

A current widespread trend in reef aquariology is the creation of so-called “coral gardens,” aquariums occupied by countless coral species. These tanks are mostly dominated by hard corals with small polyps (SPS), among which also live other invertebrates and fish.

The water is crystal clear, and the bottom, in the best cases, is covered by a thin layer of material. In these aquariums, usually, there are no macro-algae, corals grow and spread quickly, and the small fish are fed parsimoniously. This kind of aquarium is attractive and colourful, and can be maintained a lot more successfully than 30 years ago.

However, does what we see in these aquariums really resemble nature?
Or is there room for progress?
What would happen if we significantly increased the supply of nutrients?

At some point, at the end of the ’70s, what used to be impossible before suddenly became rather easy to do: being able to grow hard corals. Unexpectedly, it became possible to reproduce real reef builders such as the species of the genus Acropora, corals that were previously thought to be absolutely impossible to keep in an aquarium. Afterwords, the market was literally submerged in corals, and an always growing number of species was made available for aquariology. Therefore, it was natural that aquariofiles would develop a desire to own a hard coral aquarium. From that time, conditions in aquariums have been constantly improving. Many of the most beautiful and better functioning aquariums that are possible to see in the whole world belong to privates.

Is it possible to further improve the presence of marine animals, in terms of both quality and quantity?
Is it the right time to look for new ways?

I am convinced that the following points should be the object of a discussion:

In an artificially created environment, is it possible to increase the quantity of corals if we reduce the number of species that are kept?
Is it possible to increase the variety of species, and if so, what role do food and nutrients play?

Part 2 will follow

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by Coral_Reef_Magazine Thu 21 May 2015, 20:41

NUTRIENTS PART 2: WHAT ARE THEY?

[You must be registered and logged in to see this image.]After presenting our first editorial for the “Nutrients” series and having asked ourselves a few questions, today we will explain what nutrients are.

It is impossible to answer this question in only one sentence.

First of all we have to define the concepts of “nutriments” and “nutrients”.

Nutriments are the organic material that animals ingest and then break down, through digestion, in the individual nutritional components.
Nutrients, instead, are those compounds that make every energy-producing biochemical process in the organism possible.

Nutriment is eaten, while nutrients are assimilated and elaborated on a cellular level in the organism. Therefore, when we talk about nutrients we have to consider the biochemical processes that make the necessary energy available for every vital display, such as movement, defence, flight, reproduction, growth, metabolism and others. The complex chemical processes that are responsible for it are included in the concept of “cellular respiration”.
Cellular respiration happens in every living organism and it can be schematically expressed through the following formula:
C6H12O6 + 6O2 è 6CO2 + 6H2O + chemical energy (Adenosine triphosphate, ATP)

In a few words: a carbohydrate molecule (glucose) reacts with six oxygen molecules to give six carbon dioxide molecules and six water molecules, freeing energy (ATP) in the process. 672 kcal of chemical energy can be obtained from a carbohydrate molecule through the metabolic process. Cellular respiration is a complicated process that takes place in two phases: glicolysis, which happens in the cytoplasm of the cells, and the oxidizing respiration that happens in themitochondrion. Moreover, there are two types of cellular respiration: aerobic, in the presence of oxygen, and anaerobic, which takes place in the absence of oxygen. However, aerobic cellular respiration can provide up to 20 times more energy (in the form of ATP) than the anaerobic type.

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There are six different groups of nutrients, divided by category, which free up energy or help certain metabolic functions. Some of these substances are essential, meaning that the body is not capable to produce them autonomously (synthesize). Such nutrients therefore need to be assimilated through nutriment.

The substances that provide energy are:

Carbohydrates (sugary composites, used as an energetic deposit).
Albumin (organic composites containing nitrogen, more precisely they are plasma proteins that can provide the organism with certain amino acids that are the basic bricks for the construction of enzymes and other proteins). Certain amino acids (known as essential amino acids) need to be assimilated through feeding, because the body is not capable to produce them by itself.
Fats (made up by three molecules of fatty acids united by a central glycerol molecule). Some fatty acids cannot be produced by several organisms. Therefore these “essential fatty acids” need to be assimilated through feeding.

The substances that help metabolism are:

Mineral substances (trace elements, salts or ions, many of which are essential and indispensable for a normal metabolic process).
Vitamins (organic substances indispensable for certain corporeal functions and that mostly work as co-enzymes).
Water (absolute requisite for growth and metabolism, it is part of all the chemical reactions in living organisms, sometimes defined as the “forgotten nutrient”).

Part 3 will follow

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