Frequently Asked Questions
about the Dark Decay Assay
By Dr J Floor Anthoni , 2005
about licensing
Why is registration required?
How do you police compliance?
Should the DDA not be free for all?
Where does the money go?

about the DDA method
Why has the DDA method been overlooked?
Why the name Dark Decay Assay?
What is the difference between hion and hydrogen ion?
What were your lucky moments?

about applications
Do I need an incubator for a tropical aquarium?

about science and ecology
Are decomposers a real ecofactor since all others are physical, not biotic?
Shouldn't you have identified the species in your samples?

For suggestions and comments, please e-mail the author, Floor Anthoni
-- Seafriends home -- DDA index -- site map -- Rev 20050528,20110911,

about licensing

Q: Why is registration required?
A: The discovery that the health of our lakes, rivers and seas depends mainly on their planktonic decomposers, together with a simple method to measure it, is truly a new discovery of immense benefit. It has taken over fifteen years of study during which time a large sum was spent in personal savings, earnings and unpaid time, amounting to well over US$ 1 million.

It is only reasonable that people enjoying the benefits from these discoveries, contribute to this expenditure. The amount charged is very small compared to the benefits obtained by using the DDA and full recovery of costs may never be attainable. But people who use the DDA pro-bono or with unpaid time, are allowed to use it free of charge.

Q: How do you police compliance?
A: It is not possible to police the unauthorised use of the DDA method. There will always be people who do not wish to pay  for whatever reasons. But government departments, reputable institutions and firms cannot afford a law suit that would cost thousands more than the meager DDA registration. There are always whistle blowers and employees who check the honesty of their employers, and there is an army of bounty hunters who make a living from detecting unauthorised use. I hope that on the other hand, there will be many who wish to donate in addition to the DDA registration, simply because they wish to support a good cause.

Q: Should the DDA not be free for all?
A: Ideally, Yes. It is not unthinkable that a large organisation like the United Nations or the US Government or even the New Zealand Government buy the world rights and thereby make the DDA free for all.

Q: Where does the money go?
A: All moneys go towards the Seafriends Foundation once all outstanding debts have been cleared. The Seafriends Foundation aims to save the seas with common sense for future generations. Doing the right thing for the right reasons, at the right time. There is a lot of work to do.

about the DDA method

Q: why has the DDA method been overlooked?
A: One is never sure why certain things or methods have been overlooked by scientists, but this web site documents quite a few (See overview/challenging theories). It appears that an outsider familiar with several disciplines of science, makes a good chance seeing what has been overlooked, or joining bits together, or finding an overarching theory or paradigm.
While studying nature on land, scientists often spend very long hours just observing but this is insufficiently practised by marine scientists underwater, reason why much has been overlooked, including the causes of degradation in the sea. The missing ecofactor (the planktonic decomposers) was found because 15 years of observation raised so many conflicts or paradoxes that a missing ecofactor was suspected. With this knowledge a method was sought to measure decomposer activity, resulting in the DDA.

Science is like Swiss cheese: full of holes - Floor Anthoni, 2006

Q: Why the name Dark Decay Assay?
A: Apart from the idea that these three words form alliteration (same letters at the beginning of words) and rhyme (same letters or sounds at the ending of words), the essence of the method is to put the samples in the dark, which stops the activity of the producers (all plants) and eventually kills them. The resulting activity is purely decay, caused by the present decomposers such as bacteria. This decay frees up hydrogen ions, which is measured with an accurate pH meter. The word assay means test with the purpose of obtaining a quantity. The combination is not in use elsewhere and when searching on Internet for these three words, one should find all the relevant DDA work published. Note that another important property of the DDA is that test vials are sealed such that gases cannot escape. Note also that the acronym DDA is used in several other meanings.

Q: What is the difference between hion and hydrogen ion?
A: A hydrogen ion is a hydrogen atom that has lost (or shares) one electron (H+) and which is measured by a pH meter. The hion (lower case) is a unit of decomposed biomass corresponding to the number of hydrogen ions that make up a pH of 9. The hion is based on two assumptions: 1) that the number of hydrogen ions decomposed corresponds to the biomass decomposed.  2) that when decomposition ends, all (or almost all) biomass has been decomposed and the pH difference in hion is equal (or almost equal) to the biomass in the sample. Note that rather than biomass, the density or biodensity (biomass per litre) is measured. The hion may prove to be a more accurate way of measuring biodensity than any other existing method.
In short: hion= biodensity or biomass per litre; hydrogen ion= a hydrogen atom with a loose or lost electron.

Q: In every major discovery there has always been an element of luck. Which was yours?
A: A very profound question, since at first one doesn't recognise one's luck, wrongfully assuming to be smart or so. My luck came perhaps in stages:

  1. As an outsider I dared to think the unthinkable - that we may have overlooked the most important factor in the sea. From that jump, the rest became small steps. I was not interested in detail but in ecological functioning.
  2. Once I suspected a pH meter could be used to measure bacterial activity, but without useful results, it took a eureka moment to let the bacteria do the work over a period of time. Place the sample in the dark, which stops plant activity, and seal it to keep all hydrogen ions inside. The DDA was born.
  3. Even then I didn't realise how lucky I was, using my old 35mm film containers as test tubes, as these were made of high density polyethylene HDPE which is inert to hydrogen ions. The method would not work in glass or PVC test tubes. Thus an equipped professional laboratory would not have been able to find it. One needs to be a resourceful photographer.
  4. When a biomass calibration test failed miserably, I realised that I stumbled onto something new, the discovery of slush.
  5. Because the water in the sea moves around, one cannot derive stable results over time. Fortunately we have many lakes in New Zealand, and some have different natural pH due to volcanic activity. The DDA then revealed a linear relationship between the availability of hydrogen ions, growth rate and maximal biomass.
  6. I was also lucky that salt does not influence outcome, thus the method is equally valid in fresh as in sea water, yielding identical results.
Yes, I think I've been very lucky, but so much more work needs to be done.

about applications

Q: Do I need an incubator for a tropical aquarium?
A: No, you can use the constant temperature of the fresh or saltwater aquarium because it is also relatively high. Choose opaque black vials and let these float around in your tank or filter system.


about science and ecology

Q: Are decomposers a real ecofactor since all others are physical, not biotic?
A: Ecofactors or environmental factors are usually physical, such as moisture and temperature on land and salinity and temperature in the sea, but also biotic factors such as competition and microclimate are known. One could say that the decomposers are a product of the marine ecofactors temperature, salinity and nutrients. However, knowing these, one cannot possibly predict which decomposers or even which plankton assemblages result. Neither can one say much about productivity or the amount and aggressiveness of decomposers. So it makes good sense to measure biotic ecofactors like productivity and decay separately and treat them accordingly as separate ecofactors.

Q: Shouldn't you have identified the species in your samples?
A: Ideally, yes. But plankton species identification is a very specialised job using powerful optical and electron microscopes. It is slow and costly, yet it overlooks the hundreds of minute species (bacteria) of the decomposer guild. The DDA has shown that very important conclusions can be drawn, even when not knowing which species take part. Perhaps we should look at plankton as a single compound species with many organs (real species) that can be mounted and dismounted when needed.