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The Dark Decay Assay (DDA) for aquatic plankton ecosystems by Dr J Floor Anthoni First published: January 2005; On web: 10 Aug 2005. Since the discovery of the missing ecological factor in the sea, the planktonic decomposers, and the formulation of the Plankton Balance hypothesis, the search continued to measure and quantify the two most important components of planktonic ecosystems, the phytoplankton and the decomposers. This led to the discovery of a new procedure that enables anyone to measure the most important plankton characteristics using a simple pH meter. The DDA has opened a new window of interest on aquatic ecosystems, discovering new environmental laws in the process. This document describes the ideas behind it, methods used and results obtained. From necessity, the examples used are all from New Zealand.

For comments and suggestions, please e-mail me, Dr Floor Anthoni.
Reader please be aware that the information provided in this section is entirely new work that has not been confirmed yet by conventional science. It is therefore not suitable yet for teaching. Readtips for printing.
-- seafriends home -- DDA index -- plankton index -- decay index --
Rev 20050201, 20050630,20050810,20050830,20051008,20080703,

For over 40 years now I have been keenly observing the marine environment while taking underwater movies and later, still pictures. These gave me a kind of registration from which I learnt more as I viewed them again. It allowed me to discover the ill effects of degradation at an early stage (1987), which urged me to devote my life to this matter in 1990. Because degradation has far-reaching ill effects on nearly all species, I had to rely on observation alone to further my understanding. This led to so many paradoxes that I concluded that an important ecological factor (like sunlight, wave action, nutrient level, etc.) had been overlooked.

It didn't take long to discover that this had to be the planktonic decomposers consisting of bacteria, fungi and viruses. These living organisms are so small that they occupy the pico- and femto-plankton,  invisible to the optical microscope. What people had overlooked is that the food chain is not all the service that plankton delivers, but it also contains potent decomposers that recirculate the nutrients from wastes and dead bodies. Their task is to break dead biomatter apart, thereby consuming the last of its solar energy, as nutrients contain no such energy. Enthusiastically these decomposers will also attack living organisms such that living in the sea depends on a precarious balance - the Plankton Balance that feeds but also kills. Even those organisms not depending on plankton for food, still need to breathe it, and even marine mammals who do not breathe it, are bound to be affected.

The diagram shows the plankton ecosystem. Phytoplankton (producers, green) convert sunlight into biomatter using nutrients dissolved in the water. The phytoplankton is eaten (grazed) by the zooplankton which is in turn eaten by larger predators, which forms the food chain in its many stages, not shown here. All dead biomatter is recycled by the planktonic decomposers (brown) while larger parts sink to the sea soil where they are decomposed by the benthic (bottom) decomposers. Both kinds of decomposers return dissolved nutrients to the water, thereby closing the cycle. The planktonic decomposers play a large role because of the high turnover rates in the first stages of the food chain.

The organisms most affected by the decomposers are those taking part in the plankton, particularly the producers or phytoplankton. It was then that I realised that a kind of arms race between the two main guilds, the producers and the decomposers can have a selective influence on both. Such an arms race can be initiated by overfeeding (eutrophication) as is now common in all coastal seas. As the decomposers (the attackers) become more aggressive, the producers (phyto plankton, the defenders) become more defensive as the hardy species replace the sensitive ones. This in turn selects for even more aggressive attackers, and so on. As the phytoplankton becomes more hardy, it also becomes less digestible as at the same time the decomposers become more deadly. Thus the Plankton Balance within the plankton can shift profoundly from powering the food chain (powerplankton) to powering the decomposers while becoming a threat to all other marine organisms (killerplankton), as if the sea were eating itself! This agrees with the environmental degradation symptoms I have been observing.
I postulated that the health of the sea, particularly where eutrophication reigns, depends almost entirely on the decomposers (while not ignoring sedimentation), and that a method for measuring these was needed.
 
 

Measuring the decomposers By simplifying the planktonic ecosystem to the diagram shown here, it was realised that only a pH meter could measure the biomatter (or energy) flows, as the densities of phytoplankton are very low indeed. The producers (green arrow) photosynthesise (put together by means of energy from light) chains of living matter containing many hydrogen bonds, and therefore scavenge hydrogen ions from the water: the pH increases as hydrogen ions become scarcer. The foodchain (orange arrow) consumes the living matter and oxygenates it: the pH decreases somewhat. Finally the decomposers break the remaining hydrogen bonds, thereby returning hydrogen ions to the water: the pH decreases as hydrogen ions become more numerous. Simplistically thought, a high pH is healthy whereas a low pH is not. However, this is not quite borne out by measurements as the system is more complicated. Note the orange side loop, thought necessary in case phytoplankton respires at night, is of minor concern. But the brown side loop, which feeds phytoplankton direct to the decomposers, can become rather influential.

 

Birth of the Dark Decay Assay Taking the pH of sea water is disappointing as the resulting values do not correspond with the quality of the water such as turbidity, colour and smell. In the map for instance, measurements were done in the Manukau Harbour (New Zealand) where most of Auckland's treated sewage is discharged. As heavy nutrient loads overfertilise the water, the phytoplankton blooms at maximum density, which decreases towards the harbour mouth where the water is visibly much clearer, but this is not borne out by the pH of the water (see inset map). It then occurred to me that the producers should be disabled and 'fed' to the decomposers and the process followed in a sealed container to keep all reagents inside. By placing the test vials in the dark, the decomposers would immediately cease their activity and eventually die, to be decomposed. In the process H+ions (hydrogen ions) are released and these can be measured accurately. The graph shows how in curve A the plankton decomposes very rapidly (beginning slope) whereas its total biomass (end of decomposition) is no different from curve B. At the very mouth of the harbour, point D the decomposers are less active as also biomass density (biodensity) is less. A high tide rock pool (E) contains water with similar density as A and B but beginning with a very high pH. It was later discovered that long-lived algae excel in scavenging hydrogen ions, thereby pushing the pH up high. It was surprising that the curves showed so much latent or chronic decomposition, even when the phytoplankton should still be alive, later recognised as a sure sign of sick plankton. Note that we assumed that the released hydrogen ions are a proxy for (representative of) biomass (measured as hions), something that needs further confirmation. Note also the logarithmic nature of the pH scale where decomposed biomass increases steeply down the graph as a step from 8 to 7 represents a tenfold increase.

 

Powerplankton While using the DDA to get a feel for what it is capable of, also a coastal area was sampled, which usually has clear water, near Cape Brett, New Zealand. Travelling over a patch of water with a different smell, a sample was taken (R) which subsequently showed to consist of a peculiar plankton assemblage. For about one day and a half, no latent or chronic decomposition was measured, followed by decomposition occurring so fast that most of it was missed. As the curves are not caused by artefacts, it must be assumed that this 'suicide' is a special adaptation of the plankton assemblage, perhaps to retain nutrients in the photic (light-) zone. But it is also bound to make this type of plankton better digestible, as no pickings remain for the decomposers (proved by the flat curve at the beginning). This powerplankton thus transfers the solar energy almost completely into the food chain without threatening health. It could well be that this powerplankton powered the once bountiful coastal fisheries. Unfortunately it has now become rare, reason perhaps for collapsing fisheries world wide. It is possible that the disappearance of the powerplankton is the first sign of degradation, happening at around 12-15m visibility. One day perhaps, satellites may recognise this kind of plankton.

 

Improving the method Once the DDA had shown its promise, we concentrated on making it more accurate, as it can easily suffer from loss of hydrogen ions during the short periods of measurement. We also explored temperature stabilisation because the Rate of Attack (the beginning slope) depends on the biological activity of microorganisms, and thus on temperature. Eventually we settled for an accelerated temperature of 27ºC as the ideal incubation temperature. We also minimised the number of measurements, such that the nature of the decay curve is preserved with minimal loss of hydrogen ions to the air. With these improvements in place, measurements could now be compared from place to place and time to time, as also the whole DDA incubation is completed within two weeks.

Here is an example of a 250km round-trip in the outer Hauraki Gulf, New Zealand. The distance between points I and M is about 40 nautical miles (75 km). M is located at the territorial boundary which also marks the edge of the continental shelf. The graph shows measured pH vertically and days incubation at the standard temperature of 27ºC. The red rectangle is a movable window of 48 hours to measure the 48 hour Rate of Attack from the drawn curves. Note that decomposed biomass (H+ion proxy or hions) increases downward with decreasing pH. Note how the initial pH always climbs towards the end of the day, due to producer activity opposing that of the decomposers. Note that the total decomposed biomass at day 13 shows only small differences between sites. Highest density (lowest final pH) is D inside a small harbour whereas lowest density (highest final pH) is M. Although M has a noticeably smaller biomass, it also has the lowest Rate of Attack (5) in 48 hours. Conversely, D has the highest RoA (15). These measurements were taken at the end of summer (16 April) when the waters clear up as their nutrients have been consumed and blue water mixes with the coastal water. Even so, it was an unusually murky year with water clarity ranging from 4m (D) to 29m (P). All sites suffered from chronic decay. These results have also been mapped in the coastal map below.

 

Mapping the health of the sea The map shows the northern part of the North Island (New Zealand), with the city of Auckland straddling its narrowest part. Here the sewage of 1 million inhabitants finds its way to the sea. On the West Coast, the Waikato River flows into the sea, infused with fertiliser and excrement from stock and people from a large area of land to the south of this map. Not surprisingly, the (green) values for biomass density are very high here and with these the bacterial activity or chronic Rate of Attack (RoA). Inside the Manukau Harbour where the main sewage works are located, the RoA may reach values of 69, which are not conducive to rich life (even oysters and cockles die), but even at its mouth very high values are found (51), just tolerated by mussels. Notice that RoAs should be interpreted with care because of the possible arms race between decomposers and producers. A low RoA on hardy phytoplankters may mean a high RoA on more sensitive species. As a guideline, consider RoA<20 as healthy, 20-40 as sick and >40 as killer plankton. Following the West Coast northward, one comes across a patch of low RoA which shows how a tongue of blue water from the north lays over the more aggressive green-brown water from the south. Whereas the west coast is characterised by dirty waters, the east coast is usually clear, with 10-20m viz. However, surprises abound as RoA stays high in many places. Furthest out lies the Poor Knights Islands marine reserve where very high biomass densities and Rates of Attack (45/303) were found. Closer investigation showed a concentration of biomass near the surface, with very high bacterial activity. It explained why we saw much degradation happening in the shallows, whereas such shallows are usually exempted along the coast, due to the intensity of the waves that cleanse it, and more thorough mixing of the water.

In order to better understand the data in the above map, memorise the diagram shown here, plotting phytoplankton density (green) and decomposer density (orange) on a linear scale (but logarithmic visibility scale). It shows how the phytoplankton reaches a maximum between 4-5m viz. It also shows how the decomposers can increase suddenly between 11-9m viz. The resulting rate of attack (RoA), however, is more erratic but follows an average according to the red curve. To focus your thoughts while browsing the map, imagine a hion density of less than 60 as healthy, 60-90 as sick and above 90 as killerplankton, even though this has not been proved conclusively. Note that biodensity and RoA must be considered together. Remember also that the map is but a snapshot in time, taken in the autumn period between March and May 2005 when the water becomes clear (and healthier?). Note also that the new technique of alcohol enhancement will find different biodensity values as it also decomposes the slush in the sea.

Note how the inner Hauraki Gulf misses its RoA values (red) because measurements were done at an unknown ambient temperature. However the green values for biomass density are accurate. The data for maps like these can now be collected by conscientious amateurs equipped with a small and low-cost portable laboratory costing no more than $500. Their results can be poured into a national database with Internet access such that a finger can be kept on the pulse of the sea. Local care groups now have a tool to monitor the health of their aquatic ecosystems, a tool that also allows them to monitor the results of their actions and the origins of eutrophication.

 

Biodensity and visibility Wherever possible, we also measured the clarity of the water by a modified Secchi disc method as this provides another means of verifying the data. In theory the data points for hion biomass should lie along two straight lines marking the reciprocal relationships between visibility and phytoplankton biomass. Vertically the hion density calculated by subtracting the initial pH value from the final pH value (by proper anti-log conversion) and then plotting it again logarithmically. So it resembles the logarithmic pH scale very much. The right-hand line marks the nutrient-limited region where visibility increases proportionally as density decreases. The lef-hand line marks the light-limited region where the sunlight can maintain proportionally less biodensity if the visibility decreases (but depth also plays a role). Note in this respect that the DDA does not measure nutrient concentrations, but only their effects on planktonic life. Note also that the graph maps plankton densities rather than the total amount of plankton found in the sea. Ironically, as the water becomes clearer, it enables the sunlight to penetrate deeper too, such that the total plankton biomass over all depth strata remains almost constant between 5m and 30m visibility where it is limited by nutrients.

 

Unfortunately, the DDA method cannot distinguish between decomposable biomass originating from various sources, such as phytoplankton, sewage, dissolved organic matter (DOM) and zooplankton which tend to draw the data points down and to the left of the green boomerang where they were expected. We recently discovered an invisible thick layer of high density in clear water where this was not expected and named it the plankton graveyard, possibly an indicator of food chain failure when unconsumed biomass heaps up.  The visibility measurement on the other hand, cannot distinguish between sediment, small bubbles and phytoplankton, thereby drawing the data points to the left of the green boomerang. The combined effects are shown in the diagram, from original data. We are still in the process of mapping results as these arrive, in order to further our understanding. Also the recent technique of alcohol enhancement will have a major influence on the data points to such extent that two separate mapa may result.

Along the vertical axis, which is a logarithmic scale, also the actual values for hion density have been marked in green. The colour of the datapoints corresponds to the batches obtained from the coloured regions shown on the inset map. The datapoints marking the plankton graveyard lie in the grey shaded region. They have all been confirmed by sampling at greater depths (10, 20, 40m) where hion densities are normal.
Of main concern is the orange region between the plankton limits and the maximum densities measured. In this region the biomass of the decomposers can increase suddenly between 11m and 9m viz. Unexpectedly decomposers can attain densities exceeding that of the phytoplankton, suggesting that most degradation in the sea happens between 5m and 9m viz, which agrees with our observations! Paradoxically, a constant ingress of mud (in the light-limited region) may limit the action of the decomposers because there is less light to produce the phytoplankton that feeds them!
It would be interesting to know whether the graph shown above is valid for all the world's seas. A new map is being made with biodensities derived from alcohol-enhanced decomposition.
 
 

Decomposition deficit In the data shown above, it was thought that DDA decomposition had expired after settling (9-13 days). However, failed tests for linearity showed that decay continued rapidly after adding an energy food source (fuel) like agar, jelly, sugar or alcohol. It was then realised that the first and second laws of thermodynamics insist that the energy embedded in organic molecules cannot be enough for decomposing them. At some stage a small amount of additional fuel is needed to cover thermodynamic conversion losses.

After some experimentation, we saw that pure alcohol was the most suitable substance, as it is also the most basic of fuels, influences pH only little and is easy to keep and to administer. By adding two drops of 20% alcohol at an anaerobic stage (after day 5), decomposition resumes very rapidly, resulting in hion biodensities of two to ten times larger. Some samples (Murrays Bay, French Bay, Seafriends aquariums) even began to stink as pH dropped below 6.4! The graph shown here demonstrates alcohol's drastic effect on decomposition, as well as the ability to keep samples in one litre 'aquariums'. These aquariums were sealed and kept in a window facing away from the sun for over one month. The aquariums were then scraped with a clean dishcleaner brush to resuspend all attached algae and bacteria. As one can see, the DDA proceeds in much the same manner, with very similar rates of attack and would have ended as the original set had 2 drops of alcohol not been added after day five. The curve of Leigh Harbour (B, brown) shows how it bottomed out at day five, but under alcohol enhancement continues to reveal a biodensity of 438 instead of 78 hion!

The discovery of a thermodynamic limitation preventing complete decomposition may have profound ecological consequences on our understanding of ecosystems. It explains why plants provide fuels like sugars and alcohol from fruits to the soil, such that decomposition indeed returns the desired nutrients and minerals. In the sea it may well be the jelly component of the plankton providing the same service, or the slime produced by plants. There may be other providers like perhaps cyanobacteria using sunlight to provide for the missing fuel.
 

Freshwater explorations Lakes and rivers seem outside the interest of the marine biologist but for us they became very interesting as their planktonic ecosystems are simple and stable and cannot flow away on tidal currents. Because lakes are more tranquil, their clarity is more meaningful as a measure of phytoplankton density. They also have a large range of parameters of which intrinsic acidity or natural pH as we call it, is the most important. Natural pH is measured by eliminating all forms of life, either by complete decomposition or by other means. Each lake has its own natural pH and when their biodensities are plotted, a straight linear relationship is found as shown on the graph. Even the sea fits into this relationship (Leigh 250-330; Murrays Bay 400-600 due to ingress of raw sewage).

The lake explorations gave us the insight to link all water bodies (fresh and salt) in the world by means of a single equation. We discovered that the maximum density and productivity of life depend on the availability of hydrogen ions. Thus hydrogen ions are an important limiting factor of any aquatic ecosystem, according to the maximum biodensity formula discovered:

maximum biodensity = ALOG( 1.55 - natural pH  )   hion, where the factor 1.55 needs further confirmation.

The simpler freshwater ecosystems also showed that bacterial activity increases suddenly between 100 and 200 hion biodensity, very similar to the marine situation. Eutrophication begins here. Some eutrophied lakes have huge biodensities (Blue Lake =  2000) and corresponding bacterial biodensities and activity. Blue Lake's clarity (4m viz) defines its producer biodensity at around 250 hion, leaving 1750 hion in decomposer biodensity, or 7 times more. We discovered that the producers are able to feed this large amount of bacteria because they are extremely productive, also following the maximum biodensity formula. Read more about all this in method.htm and fresh01.htm.

The slush hypothesis or symbiotic decomposer hypothesis It is undeniable that the (un)availability of hydrogen ions is an important (but so far overlooked) limiting factor. An 'acidic' lake like Blue Lake  (natural pH=7.19) does not only have more biodensity than the sea according to the maximum biodensity formula (8-10 times), but also a correspondingly larger productivity to keep up with its high decomposition rate. The sea's pH between 8.0 and 8.3 is so high that it limits plant growth. It is also undeniable that full decomposition in the sea does not take place unless an additional bacterial fuel is provided. So the sea is apparently awash in semi-decomposed organic matter (slush, as in semi-molten snow) waiting to be decomposed further. This could have interesting ecological consequences. Plants for instance may well live in a symbiotic relationship with friendly bacteria inside the slime that they produce. As the slime feeds these bacteria, it also enables them to fully decompose the slush, providing not only the craved-for nutrients and minerals, but also for scarce hydrogen ions. The slime on plants should thus be relatively acidic (pH 7 instead of 8), which needs to be tested. One could think of seaweeds living inside a thin cocoon of slime and bacteria that offer a more productive environment. In the scarce environment of salt water, this could well be nature's solution to higher plant productivity. However, it is also a risky way of life, reason perhaps why seaweeds are so sensitive to degradation, a paradox because degradation is accompanied by higher free nutrient levels. This idea carries further to the powerplankton, which could well consist of larger phytoplankters (like diatoms) living in a symbiotic relationship with friendly bacteria and benefiting from them in a similar way. It makes these phytoplankters much more productive, while it also provides for the bacteria to rapidly decompose the host once it dies. The reason we are not measuring either productivity or decay is that this happens in a short cycle on the skin of the phytoplankter. As slush is decomposed, its products (hydrogen ions + carbondioxide + nutrients) are immediately converted into plant matter with no measurable change in pH in the water outside. This also suppresses surrounding bacterial activity as the phytoplankters act like a bacterial substrate. As the producers' productivity increases, the planktonic (free-floating) decomposers' activity decreases, which makes the plankton nutritious and safe to live in. The producers' increased productivity is evident from a 0.10 higher initial pH. The slush hypothesis also insists that corals which are known as mixotrophs (mixed-feeders) for the plant cells in their tissues, cannot work without symbiotic decomposers (bacteria) on their skins. The DDA method found high concentrations of a mysterious substance in the sea (slush), particularly in the blue desert seas with very little nutrients and chlorophyll. Mixotrophs like corals are designed to harvest this slush which has up to 8 times more biomass than the phytoplankton. This is possible only with symbiotic decomposers on their skins. It may also explain why these creatures are sensitive to changes in their environment like eutrophication and higher temperatures. Thus corals are animal + plants + bacteria. The slush hypothesis predicts that many animals like these remain to be discovered, even in the zooplankton. The photograph shows a close-up of the coral polyps of a tropical coral. Their brown colour is caused by brown symbiotic algae in their tissues. The polyps have lost their tentacles for catching zooplankton because their main food now comes direct from sunlight. Protected by their limestone skeletons, these polyps dare to expose themselves by day at risk of being scraped by fish like parrotfish. One may wonder where most of the slush comes from. The second law of thermodynamics insists that the bottom decomposers deeper than the photic zone will not be able to fully decompose wastes and dead bodies. Thus the deep sea decomposers must continuously provide slush that eventually finds its way to the surface. How this happens and how old most of the slush is, remains a mystery.

The advantages of the DDA are:

• measures the essential: even though concentrations of ammonia, nitrites and nitrates are low or acceptable, the water can still be unhealthy, which shows up in a DDA test. The DDA measures the most essential qualities of natural water in units that relate to life.
• small sampling volume: the DDA needs only 30ml sample volume; no sieving, trawling, pumping, spinning (centrifuge) required.
• rapid acquisition: all one needs to do is to take a scoop of water and divide it over several vials. The water can be kept alive in a cool, light place to be measured one or more days later, without essential loss of information.
• accuracy and range: the DDA has shown to produce accurate, repeatable and linear results over a range of four orders of magnitude (10 to 10,000).
• simplicity: the DDA can be done by school children as young as 14 years of age.
• low cost: for less than $500 one can have a portable DDA laboratory.
• portable: a small incubator operating on 12 Volt batteries can be operated from a car, a boat or by connection to a mains supply. All devices are battery-operated and portable (pH meter, salinity meter, thermometer, GPS).
• empowers amateurs: the DDA brings an important tool in the hands of conscientious amateurs, enabling them to monitor true water quality in their neighbourhoods. A network of these could be organised to generate the data for a national database of water health.

• redefines eutrophication: there exists no general agreement on what eutrophication is and when it begins. The DDA has shown that plankton can become sick when water quality is still considered good by other criteria such as visibility, oxygen content and nutrient loads. The DDA may define testable values for eutrophication. It may well be that eutrophication begins when the powerplankton disappears.
• changes the way we think: the discovery of the missing aquatic ecofactor and the DDA to measure it, will change the way we think about aquatic ecosystems and the health of these. The threat from planktonic decomposers is real and decisive and must change our thinking.
• gives solid support for the Plankton Balance hypothesis: the planktonic decomposers play a decisive role in the health of the environment; they can suddenly increase and become aggressive; when eutrophied, their biomass can exceed that of the producers many times; they constitute a formidable ecological factor which directly or indirectly affects every creature in the sea. The DDA gives solid support for this idea.
• makes new discoveries: as is to be expected from new analysis methods, the DDA will lead to many new discoveries.
• questions previous scientific work: previous scientific work did not take account of the planktonic decomposers and may become irrelevant in the light of these new discoveries. The discoveries made with the DDA may indeed affect our thinking about lake and ocean 'acidification' and global warming.
• must be included in null hypotheses: because the plankton decomposers have such a large influence, they must become part of the null hypotheses of all aquatic science. One must be able to prove that they had no effect on the results or conclusions obtained from these. This is a serious wake-up call for marine and freshwater scientists as it may also disqualify their previous work.
• marine reserves don't help: the influence of the eutrophied planktonic decomposers is now such a large part of aquatic degradation that marine reserves do not, cannot and will not work to save the sea or lakes.
• declining fisheries: the decline in the world's fisheries may not be entirely or mostly due to overfishing but to plankton degradation. It is naive to expect healthy fisheries in sick seas.
• chlorophyll as plankton productivity: the measurement and assessment of plankton productivity by chlorophyll or nutrient concentrations may not be relevant at all.

• about marine plankton
• biodensity: total biodensity can exceed phytoplankton biodensity three to one. Decomposers can form a large part of the whole.
• incomplete decomposition: in sea water the molecules of life cannot be decomposed fully without an additional source of fuel for bacteria. This may have far-reaching ecological consequences also for our understanding of terrestrial ecosystems.
• rates of attack: where a high biodensity is measured, the bacterial rate of attack is also high, but it depends on the type of plankton assemblage. Bacterial activity increases rapidly as biodensity increases, and after that proportionally.
• degradation: the measured rates of attack correspond to observed degrees of degradation. Classification of plankton as healthy, or sick, is possible from the rates of attack measured with the DDA.
• powerplankton: a plankton assemblage has been found exhibiting very low chronic decay and very high rates of decomposition once its phytoplankton dies. It is apparently able to transfer solar enegy effectively into the food chain while being safe to live in.
• status of the sea: the coastal seas we measured were in a much worse state than anticipated. In fact, very little healthy plankton was found, even in southern autumn, known for its clear waters.
• sewage: The influence of sewage, raw or treated is much more than we thought. It seriously affects large areas.
• plankton graveyard: in remote deep water where vertical mixing is negligible, we found a thick layer of high biodensity, as if the food chain was broken and food accumulated.
• natural pH: the natural pH of the sea is around 8.03 - 8.11, but in estuaries slightly lower. Measuring the pH without first disabling all life within a sample, appears maningless.
• new gradients: two new gradients were discovered: the plankton balance gradient where the decomposer activity and biodensity change as well as their ratio, and the slush gradient of incompletely decomposed organic molecules. These gradients profoundly affect sea life.
• about freshwater plankton
• incomplete decomposition: like sea water, natural fresh water does not decompose completely without the addition of a high energy food source for bacteria.
• natural pH: the natural pH of a freshwater lake is its most important quality and determines maximum density and productivity.
• density: freshwater plankton demonstrates a large range of biodensities and bioproduction, much larger (up to 8 times) than the sea. Relatively acidic lakes can accommodate biodensities of around 2000 hion (Blue Lake, natural pH=7.19).
• decomposers: the biomass of the decomposers can exceed that of the producers ten to one but freshwater life is not as sensitive to these as marine life.
• rates of attack: freshwater ecosystems exhibit low decomposer activity at biodensities comparable to those found in a healthy sea (less than 200 hion). Between 100 and 300 hion biodensity, the decomposer activity increases rapidly, followed by a proportional increase, similar to that found for the sea.
• water clarity: ironically, the decomposers help to clear the water as chlorophyll decomposes readily.
• about decomposition
• measuring precision: the DDA method of using decomposition to measure decomposer activity and biodensity has worked well with high precision, repeatability and linearity within four orders of magnitude. For the first time the nano-, pico- and femto- plankton are measured as part of the whole, opening a new window on plankton ecosystems.
• alcohol enhancement: in many samples, decomposition does not complete and a small quantity of a high quality fuel must be added, like ethyl alcohol.
• water clarity: it appears that visible chlorophyll is destroyed in an early stage of decomposition, thereyby clearing the water even though a high component of bacteria and slush or dissolved organic matter may remain.
• new ecological laws (hypotheses)
• thermodynamic conversion deficit: the energy embedded in biomolecules is not enough to decompose them completely. Another form of high-energy food must be provided to bridge the deficit and to finalise decomposition. This applies to all ecosystems, terrestrial and aquatic.
• hydrogen ions as overlooked limiting factor: the availability of hydrogen ions limits aquatic life. The more hydrogen ions (acidity) the more biodensity and productivity (but there are bound to be limits).
• maximum density of life: the maximum density of life in aquatic ecosystems is proportional to the availability of hydrogen ions according to the maximum biodensity formula.
• productivity: the maximum productivity of phytoplankton is also proportional to the availability of hydrogen ions.
• natural pH: the natural pH of a body of water is the pH it assumes in the absence of all life. It determines the availability of hydrogen ions and thereby its maximum biodensity and bioproductivity. It is the most important measurable property of lakes.
• slush hypothesis or symbiotic decomposer hypothesis: slush (incompletely decomposed biomatter) may be nature's way of increasing plant productivity, particularly in the sea where a high pH (few H+ ions) and salt (makes water less solvent) create an environment of scarcity. Plants live in symbiosis with 'friendly' decomposers which are fed high energy fuel in order to decompose slush. In return, plants receive hydrogen ions, carbondioxide and nutrients. Thus successful plants (and phytoplankton) live inside a thin cocoon of slime and bacteria. The slush hypothesis also explains how powerplankton works and mixotrophs like corals. It follows that the deep sea soil where light is insufficient, produces much slush. Slush is a large component of biodensity in clear oceans.
• powerplankton: a plankton assemblage has been found exhibiting very low chronic decay and very high rates of decomposition once its phytoplankton dies. It is apparently able to transfer solar enegy effectively into the food chain. It is postulated that this kind of plankton assemblage was once common as it powered once bountiful fisheries. As it is disappearing everywhere in the world, fisheries have become sensitive to overfishing while recovering only slowly or not at all.
• dimethyl sulphide: dimethyl sulphide (DMS) is a decomposer gas. As the biomass of decomposers is increasing worldwide due to the compound effects of eutrophication, DMS is bound to be increasing rapidly, as also its effect on weather and climate.
• invisible biomass: decomposers and slush remain invisible even though their combined biomass may exceed that of the visible phytoplankton many times.

• marine plankton: measuring the health of the water in the sea, estuaries and marinas.
• freshwater plankton: measuring the health of lakes and rivers.
• aquariums: measuring and monitoring the health of aquarium water, both fresh and salt.
• fish ponds: monitoring the biological loading of enclosed ponds.
• aquaculture: monitoring water quality to understand problems.
• mariculture: monitoring water quality in marine aquaculture open waters.
• marine laboratory saltwater systems: being aware of water quality and how to handle it for optimal health.
• tracking polluters: the origins of eutrophying pollution can be tracked and quantified.
• monitoring development: the consequences of new developments on the sea and on lakes can be monitored
• monitoring progradation: as measures are taken to lessen eutrophication, results can be monitored.
• ecosystem research: research into the functioning of ecosystem components. First of all one must know the health of the ecosystem one is working with.

aerobic: (Gk: aer= air; bios= life; life growing in air) aerobe= an organism growing in the presence of air or needing air for growth. aerobic= growing in contact with air and thus a supply of oxygen and escape of carbondioxide.
alcohol enhancement: often the DDA does not complete due to energy conversion losses, such that a small quantity of additional energy is needed to complete the decay. Alcohol was preferred over other energy foods like sugar and agar because it is the most basic of energy foods that only bacteria can make use of, almost immediately. It is also easily obtained, calibrated and kept and it does not affect the measurement. Not all samples need it but on some it makes a 300% difference! One drop of alcohol at 20% is added for every 10ml of sample liquid on day 3-5 of incubation, when decomposition slows down.
anabolic: (Gk: ana= up; ballo= throw; upbuilding) the synthesis of complex molecules from simple ones, together with the storage of energy. Photosynthesis is an anabolic activity.
anaerobic: (see aerobic) growing in the absence of or contact with air, resulting in a lack of oxygen. Animals and plants cannot live anaerobically but some bacteria can. Anaerobic decomposition produces different intermediate molecules like hydrogen sulphide which gives a putrid smell.
assay: (Fr: essay= try, test) the determination of the content or strength of a sample.
assemblage: (L: ad= to; simul= together; Fr: assembler= get together) a collection of species within an ecosystem. The assemblages of species and their numbers can change rapidly within plankton ecosystems but together they form a functional whole.
autotroph: (Gk: auto- self; trephos= feed, nourish; self-feeding) a plant; an organism feeding from sunlight.
biomass: (bio + mass) the total weight of organisms in a given area or volume, often expressed in kg dry matter. Note that the DDA cannot distinguish between living and dead organic matter and we use the words biomass and biodensity to include both.
biodensity: (bio + density) a new word to describe the biomass per litre as is necessary for planktonic ecosystems. It is expressed as dry matter per litre of liquid, or as the weight of carbon per litre.
buffer: (a thing that cushions) Chemical: a substance that maintains the hydrogen ion concentration of a solution when an acid or alkali is added or when polluted somewhat.
calomel: (Gk: calo= beautiful; melas= black) a mercury compound, medically used as cathartic (purgative). Mercurous chloride HgCl2.
calomel electrode: a conductor made with mercurous chloride, through which electricity enters or leaves a liquid or gas.
catabolic: (Gk: cata= down; ballo= throw; breaking down) the breaking down of complex molecules into simpler ones with release of energy. Decomposition and decay are catabolic activities.
chronic: (Gk: chronos= time) persisting for a long time or continuously.
chronic decay: the decomposition (decay) found even when organisms like phytoplankton are still alive. The decomposition of organisms that died earlier on. Chronic decay indicates a continuous dying of organisms, a sign of ill health.
DDA: Dark Decay Assay, a new term coined for the measuring technique that places a sample of natural water containing life forms, in a dark sealed container to achieve that plants die from lack of light while decomposers decompose these. The resulting increase in hydrogen ions, measured with a pH meter, is a proxy for the biomass (biodensity) decomposed and the activity of the decomposers. The term dark decay is also used for the loss of electronic charge in charge-coupled devices (CCDs) used for photographic imaging.
decay: (L: de-= down, completely; cadere=fall; to fall down) to rot, decompose.
decomposers: (L: de-=down, completely; com-= with, altogether; ponere= to put; to decay or rot) decomposers are an important guild of lifeforms that are able to break down the complex molecules of life, including woody substances. They consist mainly of animals with appendages to physically tear matter, fungi and single-celled bacteria, and viruses. Planktonic decomposers must from necessity be very small, consisting mainly of single-celled fungi, bacteria and viruses.
degrade: (L: de-= down; gradus= step; step down) to reduce to a simpler molecular structure, converting energy to a less convertible form. To reduce to a lower rank or degree. This word is now extensively used to describe the deterioration in the environment.
density: the degree of compactness of a substance. The density of seawater means its specific weight which increases due to saltiness. The biodensity of seawater is used to describe its density in biomass. Density is expressed as kg per litre. The density of water is 1.0.
DOM: dissolved organic matter, a catch-all term for unknown organic substances in the water. See also slush.
ecofactor: (Gk: oikos= house, environment; environmental factor) ecological factor or environmental factor or limiting factor or life-determining factor. The limiting factors on land are all well known. Of these moisture and temperature are the most decisive since life depends so much on these. But in the sea these two are of less consequence. The planktonic decomposers have completely been overlooked as an important ecofactor. The availability of hydrogen ions has also been overlooked as an important ecofactor.
ecosystem: a biological community of interacting organisms and their physical environment. An ecosystem is not a complete ecosystem if nutrients are not used by plants and regenerated by decomposers. The cycles of energy and nutrients are closed.
eutrophication: (Gk: eu-= well; trephos= feed, nourish; overfed, overnourished) an aquatic environment rich in nutrients and therefore upsetting the natural balance. It may result in obscuring light from deeper plants, excessive rot which uses up all oxygen, and aggressive decomposers that attack all life forms.
expired: (L: ex= out of; spirare= to breathe) to come to an end. This word is used to describe natural water which through full decomposition in darkness has lost all decomposable biomass and is then allowed to equilibrate (ventilate) with the atmosphere. It is natural water that has lost all its solar energy. The resulting pH is called natural pH.
femtoplankton: (Danish: femten, femto= 15) 0.02-0.2 µm (viruses)
fuel: (L: focus= hearth; Old French: fouaille) a material used as a source of heat or power. It describes food high in energy like carbohydrates but low in proteins, like sugars and fats. Alcohol can be used as fuel for yeasts which convert it to vinegar in the presence of oxygen, but only bacteria are able to use alcohol as fuel in the absence of oxygen.
glass electrode: the glass bulb electrode used for measuring the pH of liquids.
graveyard: (plankton graveyard) a descriptive word for the dense plankton biomatter aggregating near the surface in layers up to 5 metre deep. See also slush.
healthy plankton: a name used to describe a plankton assemblage high in food value but low in bacterial threat to health. It is used qualitatively but may later be defined quantitively.
hion: a new unit, introduced here as a proxy for biodensity. One hion is the amount of biomass per litre decomposed in darkness, measured in pH units. It is calculated from the initial and final pH values as: antilog( - final pH) - antilog( - initial pH) in parts per billion (1E-9). The number of hydrogen ions at a pH of 9.00 corresponds to one hion. The hion unit allows for comparison without knowing the actual densities as dry organic matter per litre.
hydrogen ion: a free hydrogen atom with the charge of one unit. H+
hydronium ion: the same as a hydrogen ion, but describing it better as still bound to a water molecule: H2O.H+ or H3O+
hydroxyl ion: the OH- ion, counterpart of the hydrogen ion. Bound together, they form water HOH. Some of the water is dissociated into (relatively) free ions H+.OH-
incubator: a box or bath that keeps a constant temperature for hatching eggs or nursing premature babies, or for growing micro-organisms. Since the DDA technique relies on the activity of micro-organisms, it is sensitive to temperature. The incubator used with the DDA enables one to compare results wherever and whenever.
killerplankton: a plankton assemblage very high in chronic decay, showing a steep drop in its DDA curve and high biodensity. This kind of assemblage transfers the solar energy into the bacteria rather than the food chain. Its high bacterial activity threatens all aquatic life forms.
latent: (L: latent= hidden) concealed, dormant. Existing but not well developed. Ever-present but not developed.
lysis: (Gk: lysis= loosening) the disintegration of a cell.
mesoplankton: (Gk: mesos= middle) 0.2-20 mm (copepods)
microplankton: (Gk: micros= small)  20-200 µm (diatoms, dinoflagellates)
mixotroph: (L:miscere= to mix; mixtus= mixed; Gk:trephos= to feed, nourish) an organism that feeds in mixed ways, referring to animals with plant cells in their tissues like corals and some anemones. The new slush hypothesis insists that these organisms can exist only if they have symbiotic bacteria as well. Thus corals are animal + plant + bacteria. Mixotroph species are also bound to be discovered in the zooplankton. The unicellular mixotrophic microbes are capable of feeding from both sunlight (phototroph) and something else (phagotroph), and these are found amongst many single-celled aquatic organisms (flagellates [dinoflagellates, prymnesiophytes, chrysophytes, cryptophytes], ciliates, sarcodines,  and radiolarians) as well as in sponges, corals, rotifers, and even in higher plants
mol, mole, molar: (from molecule) the SI unit of amount of substance equal to the quantity containing as many elementary units as there are atoms in 12 gram of carbon-12. Thus one mole of water contains two hydrogen atoms of weight 1 and one oxygen atom of weight 16, totalling 18 gram.
nanoplankton: (Gk: nanos= dwarf) planktonic microbial organisms between 2 and 20 µm in size. (diatoms, dinoflagellates, coccolithophorids)
natural pH: the intrinsic pH of natural water without any influences from biotic (life) factors. It is water that through full decomposition in darkness followed by full exposure to the atmoshpere, has lost all its solar energy and thereby all possible influences that could have altered its pH.
pH: potential of hydrogen, meaning the electrical potential caused by hydrogen ions. It is about 60mV per pH unit. A logarithm of the reciprocal of the hydrogen ion concentration in moles per litre of a solution, giving a measure of its acidity or alkalinity.
phagotroph: (Gk: phagos= eat; trephos= nourish) an organism that eats something to nourish itself: grazers, predators, scavengers and detritus-feeders but is mainly used for small planktonic microbes.
photic: (Gk: phos, photos= light) relating to light. In aquatic systems the photic zone refers to the depth to which light still causes photosynthesis. Light is easily diminished by dense plankton and mud.
photoheterotroph: same as mixotroph.
photosynthesis: the process by which the energy of sunlight is used to synthesise carbohydrates and other molecules of life from carbon dioxide and water and other elements.
photototroph: (Gk: photos= light; trephos= feed, nourish; light-feeding) a plant; an organism feeding from sunlight.
phyto-: (Gk: phyton= plant) relating to plants. Phytoplankton is the assemblage of plant plankton.
picoplankton: (Spanish: pico= a little bit) planktonic organisms in the range of 0.2-2 µm, mostly bacteria. (cyanobacteria, other bacteria, Prochlorococcus, and Synechococcus). The open oceans contain mostly picoplankton to 200m depth. Marine pelagic bacteria are small: 0.03-0.4 µm.
phagotroph: (Gk: phagos=food; trephos= feed, nourish; a something eater) to distinguish plants (autotrophs or phototrophs) from all others (phagotrophs) like grazers and predators. But bacteria living from Dissolved Organic Carbon (DOC or slush) are called saprotrophs. Phagotrophs have no photosynthesising pigments.
plankter: a single plankton organism. Hence zooplankter and phytoplankter.
plankton: (Gk: planktos= wandering; plazomai= to wander) organisms spending some part of their life cycle suspended in the water. It includes jellyfish, larvae of non-planktonic adults, microscopic animals living entirely planktonic, single-celled plants of a large range of sizes and single-celled decomposers including bacteria and viruses. Plankton is conveniently divided into groups depending on size:  Megaplankton 20-200 cm, Macroplankton 2-20 cm, Mesoplankton 0.2 -20 mm, Microplankton 20-200 µm, Nanoplankton 2-20 µm, Picoplankton 0.2-2 µm (mostly bacteria), Femtoplankton smaller than 0.2 µm (marine viruses). Note in this respect that the wavelength of blue-green light is 0.5µm.
plankton balance: a new term coined by us drawing attention to the dual nature of plankton: on the one hand it feeds with the plant matter it synthesises, whereas on the other hand it kills by means of its decomposers. The plankton balance within the plankton can change rapidly from being nutritious and healthy (power plankton, healthy plankton) to being a threat to all life, without providing digestible food (sick plankton, killer plankton).
powerplankton: a plankton assemblage very low in chronic decay, showing a flat shoulder in its DDA curve, lasting for over 24 hours, followed by very rapid decay. It is postulated that this kind of assemblage provides the most food value for the least threat by committing suicide (lysis). The loss of this kind of plankton could have serious consequences for fisheries.
producer: a photosynthesiser or plant.
prograde: the opposite of degrade, a new word denoting improvement in the environment.
proxy: (from old English procuracy= the taking care of; L: procurare= to take care of, to buy for someone else) a person authorised to act as a substitute. In the case of the DDA method, the measured change in hydrogen ions is a substitute for density of biomass in the sample. The proposed unit for this is the hion.
RDOC: Recalcitrant or Refractory (stubborn) Dissolved Organic Carbon, the name used in some scientific articles for a fraction of DOC that is resistant to bacterial decomposition. It is identical to our term slush.
RoA: Rate of Attack. The rate at which decomposers decompose biomass, particularly at the very beginning of the DDA test, when phytoplankton in the sample is not deemed to have died yet. The Rate of Attack measures decomposed biomass in hions after a set time, like 48 hours. For convenience we use RoA48 and RoA24.
saprotroph: (Gk:sapros= rot; trephos= feed, nourish) a decomposer living from rot but more specifically, an organism living from DOC (Dissolved Organic Carbon) like slush. These are obviously bacteria.
scavenge: (from Flemish: scauwen, schouwen= to show) to search for and collect discarded items (from a beach or dump). It is used to describe the process of obtaining 'free' but infrequent items, like carbon dioxide from air (one in 3000 molecules) and hydrogen or other ions from water.
Secchi: Fr. Pietro Angelo Secchi, an Italian astrophysicist, was requested to measure transparency in the Mediterranean Sea by Commander Cialdi, head of the Papal Navy. Secchi was the scientific advisor to the Pope. Secchi used some white discs to measure the clarity of water in the Mediterranean in April of l865. Various sizes of discs have been used since that time, but the most frequently used disc is an 8 inch (20cm) diameter metal disc painted in alternate black and white quadrants.
The Secchi disc is used to measure how deep one can see into the water. It is lowered into the water by unwinding the waterproof tape to which it is attached and until the observer loses sight of it. The disc is then raised until it reappears. The depth of the water where the disc vanishes and reappears is the Secchi disc reading. The depth level reading on the tape at the surface level is recorded.
sick plankton: a new name for a type of plankton assemblage with high bacterial activity (and threat to life) but low food value. At present used qualitatively.
slush: (comes originally from sludge; watery mud or thawing snow, indicating its half-accomplished state) a new word to describe the incompletely decomposed biomass in the sea which waits for an additional bacterial fuel to complete the decomposition process that finally releases nutrients. The term Dissolved Organic Matter (DOM) covers all forms of biomatter, including slush.
symbiont: (Gk: syn-= with/together; bios= life; symbio= living together) two organisms of different type living together for mutual benefit.
thermodynamics: (Gk: therme= heat; thermos= hot; dynamis= power) the science of the relationships between heat and other forms of energy. dynamics= any branch of science in which forces or changes are considered.
vial: (Gk: phiale= a broad, flat vessel) a small glass container, especially for holding liquid medicines. A test tube.
visibility: the range of vision as possible with given conditions of light and atmosphere. In this chapter, visibility means the distance one can see objects under water. It is measured by looking at a white object to see its shape disappear. See also Secchi above.
viz: divers' short word for visibility.

nzmss.rsnz.org/pubdocs/pdfdocs/Review_45_2003.pdf  Presentation of The Plankton Balance Hypothesis to the New Zealand Marine Sciences Conference 2003 in Auckland. (p29 of 171pp, June 2004)
nzmss.rsnz.org/pubdocs/pdfdocs/NZMSS47.pdf Presentation of The Dark Decay Assay (DDA), a new technique for measuring the health of plankton to the NZMSS conference 2005 in Wellington. (p23 of 271pp, Aug 2006)

yyyymmdd - description
20080703 - new page added about scientific publications that support or refute our discoveries.
20060712 - DMS and cloudformation diagram added to dda for dummies.
20051008 - DDA for dummies added (10p) and corrections made to various chapters.
20050830 - Changes made to the wordings in various chapters
20050826 - Presented to the NZ Marine Sciences conference 'human impacts on the marine environment' in Wellington.
20050803 - Published on the Web
20050510 - A beginning made writing the DDA chapters.
20050109 - Discovery of the Dark Decay Assay method
20030902 - The Plankton Balance hypothesis presented to the NZ Marine Sciences Conference in Auckland, NZ.
20030617 - Discovery of the missing ecological factor in aquatic ecosystems, the planktonic decomposers.