food chain: how life depends on sunlight, tiers of the food chain, recycling, marine food chain, ecosystem. closed ecosystem: in an ecosystem all loops are closed by the decomposers. slush: decomposition ends prematurely, producing a mysterious organic substance we named slush. It has profound consequences on our understanding of ecosystems. The slush hypothesis explains why and also how mixotrophs live. living in the sea: all creatures in the sea have to cope with the planktonic decomposers which are a threat to life. Each organism finds a suitable place to live along a plankton density gradient, the Plankton Balance. degradation: pollution in the form of overnourishing, mud and other substances stunts growth and kills organisms. It has become a major problem which is accelerating fast. sea water: in order to be able to understand the DDA and pH, one must understand the properties of water and sea water. lakes: freshwater lakes differ remarkably in their properties which leads to higher densities of life and higher productivity. We discovered some important ecological laws that have been overlooked. DDA: a new method to measure the health of aquatic ecosystems, is simple, effective and cheap. what now?: what does it all mean and what is the way forward? How important is the DDA? What profound consequences come from symbiotic decomposition? reference documents: periodic table of elements: basic chemistry and the systematics of chemical elements glossary of terms: the meaning of scientific words used in marine biology and ecology

Animals can live only because there are plants in the first place. The first tier of animals consists therefore of grazers. They grow by disassembling (digesting) plant matter and incorporating molecular building blocks into their bodies. They too assemble large molecules from smaller ones, and need energy which they derive from the solar energy stored in biomolecules like sugar and starch. They use the 'easy' energy stored in food.

With the grazers in place, there is food for the predators who eat animal flesh, which provides for high quality molecules that can be incorporated readily for growth requiring a minimum of breaking down. They rely mainly on fat for their energy. Then there is a place for predators of predators and so on. Meat eaters metabolise the 'easiest' of energies in food.

But all these categories of life also produce waste. Plants drop their leaves and animals drop waste. They also waste energy on living. So the amount of energy and biomass stored in each higher tier of life, is from necessity much lower than the tier below. About 5 to 10 times lower, depending on how fast everything cycles and how much is wasted. If there were no recycling, the source of nutrients would rapidly disappear, but fortunately wastes are recycled by decomposers into the nutrients needed by plants. Thus an army of microbes use up the last of the solar energy, stripping the last hydrogen, oxygen and carbon (HOC) from the biomolecules and returning the nutrients (NPS) in a soluble form that plants can take up with their roots. The whole of this interdependency of life, complete with a cycle of energy and biomass, is called an ecosystem. Note that the microbic decomposers use the most 'difficult' left-over energy of food (wastes).
 
 

The simple diagram shown here illustrates the food chain of the sea. Most of the plant matter in the sea consists of phytoplankton (plant plankton) which floats in the water in sun-lit depths. Seaweeds are also important but because they are restricted to the very small strip of hard shore to which they attach, there is comparatively very little of it. Plants cannot grow very deep in the sea because water absorbs light and the plant life in the water absorbs light too. So we find plants no deeper than 15m along the coast and 35m in clear water. Phytoplankton lives somewhat deeper because currents and eddies move it up and down the water column.

The diagram shows how life begins with a large amount of phytoplankton, which keeps a much smaller amount of zooplankton (animal plankton) alive. This is then eaten by larger animals like fish fry and shrimps, which get eaten by larger fish and so on, but each tier is 5-10 times smaller than the previous. Because all these organisms are cold blooded, they do not waste energy on heat, which is one of the reasons that the ocean food chain has many tiers. It is interesting to note here that sea creatures are very wasteful in their reproduction. A mature snapper for instance, produces millions of eggs just to make one adult fish. But this waste is necessary to produce the many small animals in the food chain, which make the packets of solar energy larger and larger until finally the mature snapper can eat it too. Sea creatures thus produce eggs mainly for food (99.99%) rather than reproduction (0.01%). It is indeed a strange fish-eat-fish world.
 
 

closed ecosystem A food chain is not an ecosystem until all loops are closed and the nutrients of life returned to the plants. In this diagram the marine food chain has been simplified to three tiers and three new components added. Small waste particles are decomposed in mid water by the planktonic decomposers and the resulting nutrients dissolved so that seaweeds and phytoplankton can reassemble them again into molecules of life. Larger waste particles and dead bodies sink to the sea bottom (sea soil) where the sea soil decomposers do the same. Notice that solar energy is locked up in all the coloured circles, except for the pink one, the nutrients which do not contain any usable energy.

The main differences between the two guilds of decomposers are:

• the benthic (bottom) decomposers are mainly locked up inside the sea soil, very similar to land soil, as they live attached to sand grains and inside tunnels. By contrast, the planktonic bacteria are in the open and in contact with every organism that swims around.
• the benthic decomposers can be larger, consisting of animals with nippers and cutting tools to cut large pieces into ever smaller ones until only bacteria can do the rest. Thus many of the benthic decomposers like crabs and worms form an important food source, whereas the planktonic decomposers consist mainly of invisible bacteria.

Slush is not a new invention by nature and has been around as long as life existed. Naturally, nature has found a way of decomposing it, or else the oceans and lakes would contain only slush and life as we know it would not be possible. Scientists have just not been aware of it and how it functions. It is a remarkable substance because it is entirely transparent and invisible and can reach high densities without affecting the clarity of the water. It is also difficult to measure.

Our slush hypothesis or symbiotic decomposition hypothesis explains how plants use bacteria to obtain benefit from slush. By excreting slime with sugars and algins, algae create an incubation mat for bacteria on their skins. The additional energy food enables the bacteria to fully decompose slush from the water around, a great benefit to the host who not only receives the desired nutrients, but also carbondioxide and hydrogen ions, all products of decomposition. It enables seaweeds to be more productive than they could otherwise be. It is plants' interest to make more slime and sugars and to slough (sweat) them off, because, detached from the plant, they still continue their important role in decomposition.
We'll see later that another discovery by the DDA is that the availability of hydrogen ions is of major influence to aquatic productivity. It so happens that these hydrogen ions are very scarce indeed in sea water, as measured by its pH. So, obtaining them through symbiotic decomposition is of great benefit to sea plants (algae, phytoplankton and even corals). More about this later.
 
 
 

Thus the aquatic ecosystem diagram above now needs to be modified as shown here. The food chain essentially remains unchanged, but in the return path of decomposition, a new guild of decomposers, the symbiotic decomposers, has been drawn. They live on the skins of aquatic plants and convert slush to nutrients (and carbondioxide with hydrogen ions). With these additions we're now getting a step closer to how the sea and lakes work. One would think that slush remains a small part of the biomass in the oceans, but our measurements showed the opposite.

Remember that the world's oceans are very large and very deep so that most of the sea column never sees light. Symbiotic decomposition in this underworld is thus not possible, resulting in a high production of slush that slowly finds its way to the surface. Only in the presence of light and plants can slush be decomposed further. In the island state of Niue, which is surrounded by a gin-clear blue ocean, we found that although phytoplankton biodensity there is nearly ten times less than around a continent, the biodensity of the slush is so high (8 times) that this very clear water contains half the biodensity of that around continents.

The thermodynamic conversion deficit is so essential a principle, that it must apply to all ecosystems found on Earth. It explains why fruits are sweet because their sugars need to assist decomposition in the soil. Many plants sacrifice their roots to further decomposition in the soil, and they also supply energy food (sugars, slime) through their roots to the soil.
 

The slush hypothesis also explains how corals live. A long time ago scientists discovered that corals can live in seas with very little zooplankton (the normal food of polyps) because they have symbiotic algal cells (zooxanthella, a primitive dinoflagellate) inside their tissues. These symbiotic plants, it was thought, convert sunlight to food using the scarce nutrients around, and if the animal shares its wastes with the plant cells, it becomes a self-contained ecosystem, able to live from sunlight. Our slush hypothesis changes this somewhat by postulating that these mixotrophs (mixed-feeders) have decomposing bacteria on their slimy skins. The sugars produced by the plant cells are passed through the skin to the decomposers which enables them to decompose the slush of which there is vastly more than nutrients (and also invisible). Also the polyp's wastes are passed to these decomposers living on their skins. Because there exists so much slush in the blue oceans, the hypothesis also predicts that many more organisms in several phyla have adapted to this mixotrophic way of life, waiting to be discovered.

Our newly discovered plankton balance hypothesis explains this and its consequences. This too should have been entirely predictable, but remained unrecognised until we discovered it as a major missing ecological factor that has been overlooked. Read more about it in the plankton balance chapter.

In the sea there exists a gradient (gradual change) in the density of the plankton soup, being densest in estuaries where rivers bring new nutrients, freshwater plankton and mud, and thinnest at outlying islands near the edge of the continental shelf where the water is much clearer. Along this gradient, the sea creatures (both plants and animals) find the best place to live, and this explains their general distribution. But what happens when the gradient changes, as for instance when people pollute the sea?

Then every creature has to pack up and move to a new place. But the sessile (sitting) ones can't do this, so they die as their offspring establish in more suitable places. Thus a changing gradient results in widespread death, which is what we have observed in recent times. If gradients keep moving (sometimes to and fro), this results in an overall scarcity of life and variety, as if the sea is dying. This in turn creates much open territory, which can then be occupied by foreign species that are more suitable to the new conditions. In a country like New Zealand which over eons of time has enjoyed clear seas, degradation of the marine environment and invasion by new species has become quite prominent.
 
 

The amount of pollution in seas and lakes has become very harmful, but where does it come from and what harm is done? The diagram shows on left what humans do, then what substances are produced, and on right what these substances do to the sea. It looks rather complicated, and indeed it is, but the words are familiar and you can follow each of the arrows from left to right. For a complete description, read the chapter on marine conservation/causes&effects. If we want to save the sea, we have to reduce every arrow in this diagram.

Quite understandably, scientists have concentrated on the visible side of degradation, mainly the harm caused by mud (sedimentation, deposition) but we discovered that the invisible decomposers (bacteria) are the main factor in degradation. The decomposers are associated with death, such as dead phytoplankton, their main food source. When the density of the phytoplankton increases, their decomposers follow suit, but then suddenly the baddies take over and the plankton becomes dangerously sick when equally suddenly its food value diminishes as simultaneously its threat to life increases. So the plankton balance  factor plays a major role inside the plankton. In this manner even killer plankton can emerge, which has no practical food value because the phytoplankton (the solar energy) is consumed in its entirety by very aggressive bacteria. To our surprise, the first major change in the quality of the plankton with its accompanying degradation, happens when the water is still considered 'healthy', between 15 and 10 metres visibility. This agrees with our observations of widespread death to underwater life.

If you want to see what degradation looks like, visit the decay section.

From a chemical perspective, water is unique because it is the only known substance that is both an acid (with an excess of hydrogen ions H+) and a lye (with an excess in hydroxyl ions OH-). Thus it is attractive to many kinds of substance (acids, lyes, salts) that because of this, dissolve easily. Water is therefore the perfect carrier for the molecules of life and the minerals and nutrients associated with life.

The balance between hydrogen and hydroxyl ions is measured with a pH meter, which essentially only measures the concentration of hydrogen ions. In neutral pure water not all water molecules are dissociated (split) into ions, but only one in every 600,000,000 which is very scarce. (concentration at pH=7 = 10^-7 mol/litre = 1E-7 x 18/ 1000 = 1.8E-9)  By comparison, carbondioxide is so scarce in air (320ppm by molecules) that it limits plant growth on Earth. Yet one in about 3000 molecules is carbondioxide.
The concentration of hydrogen ions can be measured with a pH meter and neutral pure water corresponds to a pH of 7. Every step on the pH scale corresponds to a ten-fold increase or decrease in hydrogen ion concentrations. The pH or the availability of hydrogen ions, is what the DDA method measures while a plankton sample is decomposed. To read more about pH and how a pH meter works, read the pH chapter.

The salt molecule sodiumchloride (NaCl) is of all salts, perhaps the easiest to dissolve in water, again because of its small size and shape which locks in perfectly with the water boomerangs. In doing so, it forms larger islands of liquid water, which leaves less space for other substances to dissolve into. Salt water is therefore much less solvent than fresh water, reason why soaps won't  foam or lather (other minerals in seawater are also responsible).

Sea water contains many salts (see the composition of sea water), which altogether raise the pH to about 8.1 (the pH of pure water is 7.0; rain water which is saturated with CO2, has a pH of 5.5), compared to that of lakes which is between 6.0 and 7.0. Thus hydrogen ions are much less readily available in the sea, which as we discovered, is of major importance to productivity and maximum attainable biodensity.
 
 

The Woods Hole Oceanographic institution has been studying the acidity of the sea for a long time, resulting in this map. The acidity of the ocean is not constant as it changes from place to place, from a low of 7.8 to a high of 8.2. Low pH (but still alkaline) is associated with upwelling areas of high productivity. In a given place, it is not constant either as it is higher at the end of the day compared with the end of the night. Areas with intense eutrophication are relatively more acidic.

We also discovered that high productivity is mainly consumed by bacteria and that the clarity of a lake can be very deceptive, since bacteria remain invisible. To our surprise, the sea with its high pH fitted well within the newly discovered laws of productivity, which means that the sea is disadvantaged by its low availability of hydrogen ions (high pH). Fortunately, the newly discovered slush and symbiotic decomposition come to the rescue as these provide for the missing hydrogen ions. It appears as if marine algae thrive in a thin cocoon of slime that lowers the pH (providing hydrogen ions). But having decomposers so close also means that marine algae live in a risky situation that can easily be disturbed. It is not surprising therefore, that they are so sensitive to degradation and very difficult to keep in aquariums.
 

DDA, Dark Decay Assay The Dark Decay Assay is a newly discovered test method to get a grip on how degradation works. From extensive observations we postulated that the planktonic bacteria were the main ingredient of degradation but we needed a way to prove this. Research of plankton is severely hampered by the difficulty of collecting (straining) it, its many players in a very large range of sizes and the fact that it changes rapidly. Plankton biodensity is also very low, which excludes many scientific instruments as they are not sensitive enough. We then knew that we needed to simplify the planktonic ecosystem to its most basic form, as shown here.

The zooplankton eats the plant plankton and digests it but they breathe oxygen ('burning') and the pH does not change much. Besides, the biodensity of the entire food chain is much less than that of the phytoplankton, so we can safely ignore the whole orange arrows. Note the small side loop which we thought necessary in case phytoplankton respires (breathes) like plants at night. But we have not been able to measure this.

Wastes and dead bodies are decomposed by the planktonic decomposers (brown arrow) who break all the chemical bonds, including hydrogen bonds, and return hydrogen ions to the water (pH goes down). Notice the small side loop direct from the green plants to the bacteria, which represents how dead phytoplankton feeds the decomposers direct. This arrow can become very prominent as plankton becomes sick, attacking live phytoplankton as well.

With this simple understanding of an oversimplified ecosystem, we thought that a pH meter made a good chance, as it is extremely sensitive. Fortunately for us, high precision (three-digit) pH meters had recently become affordable.

The pH one measures at any time (in light) is the result of algae pushing the pH up and at the same time decomposers pulling it down. In order to measure the behaviour of the decomposers therefore, the plants had to be disabled by simply placing the sea water sample in the dark and measuring how pH behaved. Because the samples are hermetically sealed, gases cannot escape and hydrogen ions remain in solution. We then postulated that these would be a good measure (proxy) of biodensity because hydrogen atoms are an essential and predictable part of living matter. Thus the change in pH represents the amount of biomatter decomposed, and when decomposition halts, the total biomass in the sample. Because a pH meter measures densities, the method does not measure biomass but biodensity (biomass per litre). Now a new biodensity unit was needed and we posited (proposed) the hion as new unit of biodensity, which is 1 for the hydrogen ion concentration at a pH of 9.00. One day this unit will be equated to actual biodensity (grams biomatter per litre) but for the moment this is not strictly necessary since all comparisons are made using the same hion unit. Because the pH scale is logarithmic, the hion scale shown alongside it, is also logarithmic.
 

This graph shows two groups of DDA measurements. They originate from a long coastal trip following a 40 nautical mile (75km) transect to the edge of the continental shelf (S-E-C-D). Notice how accurate the DDA is and how the curves flow smoothly along without much criss-crossing. The total biodensity of the phytoplankton is represented by the top group which measures around 30-80 hion, a range from good to medium quality water. The first drop in pH over the first 48 hours is representative of decomposer activity and it is measured with the red 48-hour rectangle. So we end up with two essential measurements: total biodensity and bacterial attack or rate of attack (RoA). This roughly corresponds with the good side and the bad side of plankton as postulated by the plankton balance hypothesis. We'll come to the second group later (slush).

The simple DDA method now enables us to objectively measure the quality of the water in units that make sense to the environment, while also representing the two most important qualities of the plankton. The idea is simple: one cannot have a healthy environment in a sick sea. When the plankton becomes sick, the marine environment suffers proportionally. But there remains a problem. Our measurements are but snapshots in time and the water quality changes daily, seasonally and annually. This is why underwater observations remain important. The most important figure is the red rate of attack, which should not exceed 10 for healthy plankton. What we see is that there are distinctly different bodies of water. One of the key findings was the very high rates of attack in the top-right for the famous Poor Knights marine reserve where both healthy and very sick water is found, and this at the best time of year (autumn). It confirms recent observations of extreme degradation.

Even extreme degrees of degradation have not been noticed by divers and scientists alike. This graph shows chronic decline of non-fished species in a non-fished marine reserve, the Poor Knights in New Zealand. The data was measured by marine scientists who studied how the reserve improved after total closure in 1998. Most of the fish graphed here have never been fished, some because they are plant eaters and others because they have not been targeted by floating fishing lines. The curves were gleaned from a scientific report that did not mention a word about it. The graph clearly shows the chronic decline of fish, which we have observed for over a decade before 1998. Only one fish species increased, sweep (Scorpis lineolatus) which is a near-coastal fish tolerant of poor quality water. This decline agrees with the DDA observations in the map above, as well as with our own observations.

We have now brought together an overwhelming mass of evidence that shows that marine reserves cannot work where degradation reigns and the above graph is living proof of that. Read the war for marine reserves for more. But if non-commercial non-fished species are affected, would the commercially fished species somehow be exempted? Of course not. Whereas fishermen affect the adult fish, degradation mainly affects their larvae, resulting in recruitment failure. New Zealand has now entered a new era with fishery collapses where fish stocks are determined by degradation. But elsewhere in the world, this has been going on for quite some time.

Going back to the coloured graph above (Leigh to Mokohinau), the second group of curves was obtained by adding a tiny amount of ethyl alcohol (as in an alcoholic drink) at day five. As you can see, this provided enough energy food for the bacteria to continue decomposition of what remained as slush. Adding more alcohol was not able to decompose any further and we believe that the end of the curves represents the total biodensity including slush. We understand why slush is dense as one nears the blue waters (because it arrives from the deep sea bottom), but it also occurs in areas where treated or untreated sewage is discharged. We observed that sewage may have a much worse effect on the marine environment than we have suspected but much more work needs to be done.

The DDA is an exciting technique that because of its simplicity, can be done by amateurs at a very low cost. It allows them to measure objectively the health of the sea, rivers and lakes and it bring us a step closer towards saving the sea. The measurements are stable and accurate, such that they can be compared with other places in other times.
 
 

The Dark Decay Assay is done with a 3-digit pH meter which also happens to be waterproof. The vial contains only 30ml of sea water, which makes the DDA perhaps also the most sensitive plankton test available. The vials are standard Fuji 35mm film canisters made from High Density Polyethylene HDPE.

In order to be able to compare results from place to place and time to time, the temperature needs to be stabilised, in this case with a modified car fridge for a six-pack of beer. Two trays contain 24 vials each. The whole laboratory is portable and works at home, in the car or on board, and even on a plane.

On the Seafriends web site we have now brought together a coherent and harmonious set of theories (which remain hypotheses until proven beyond doubt) which explain how the sea really works and which also have predictive power. We have brought together the science needed to understand how the soil degrades and erodes, how this affects the sea and how degradation in the sea works. We now even have the tool needed to assess how sick our seas and fresh waters are, a tool that can also be used to measure progress while turning the tide. Everything we need to combat degradation, all the answers are here. We now need to assess their relative importance and cost. Then we need to act.

We now need scientists to become engaged and attempt to prove us either right or wrong. With their much better facilities they will be able to carry our humble beginnings further. In the meantime we can still progress the DDA by improving its accuracy, doing more seasonal studies and mapping the health of the sea. We are interested in developing several scatter diagrams further such that each body of water on this planet can be placed on these diagrams as a single dot, representing an objective measure of their health.

We are particularly interested in assessing the damage caused by sewage alone, because this can be turned into an advantage so easily and so quickly by shipping it out to sea, outside the continental shelf. Here swaths of ocean can be fertilised with it and monitored by satellite. As a new fishery is created there, we are also salvaging the old coastal fishery, resulting in a double benefit and it is cheaper in many cases than treating the sewage.

We need strategically placed conscientious amateurs who are willing to give some time for the sake of a better future for all. They must be able to obtain samples from the seas, lakes and rivers where they live or that they visit frequently. They must be able to deliver consistent and high quality measurements. We must have government departments with vision, able to place resources into the hands of amateurs at the lowest possible hindrance. Is that too much to ask for?
 
 

Could degradation make hurricanes more destructive? What an outrageous thought! Of course not! However, let's follow this idea through. Recently there have been more hurricanes and stronger ones too. There have also been more torrential rains. Hurricanes feed off warm water that allows more water to evaporate more quickly, resulting in more water droplets and bigger ones, feeding hurricanes with their thermal energy. Global warming could do this but not so suddenly and so soon.  We've seen that the gas dimethyl sulphide (DMS) is produced by decomposers and that the sea can quite suddenly become sick, feeding the solar energy to these decomposers, thereby suddenly producing more DMS. This makes more cloud more quickly and with bigger droplets, as if the sea was warmed by a few degrees, resulting in more powerful hurricanes and more of them. Crazy as it sounds, we can't dismiss this idea, as the example shows how the planet's processes are interlinked in mysterious ways. The diagram shows how much the DMS molecule resembles that of water. Together with their negative and positive polarities, transparent water vapour molecules attach to the DMS molecule, forming water droplets. So DMS promotes cloud formation and heavier droplets, which could cause heavier rains and hurricanes. Cloud formation also cools the planet, thereby counteracting the warming effect of greenhouse gases.