Saturday, 1 February 2014

Eelgrass And Circular Reasoning

ScienceShot: Mysterious Underwater Circles Explained | Science/AAAS | News

The thing about geometric shapes like circles is that they look designed. They look as though something intelligent made them deliberately.

A few years ago a tourist took some photographs of mysterious rings that had appeared in the sea near the chalk cliffs of the island of Møn in the Baltic Sea and a host of magical theories, conspiracy theories and other wacky notions sprang up, all claimed to be the cause of the circles and the circles to be evidence of the cause. Each theory (and I use the term in its non-scientific sense here) claimed to be the cause of the rings and claimed the rings to be proof of the theory.

Now scientists have discovered that the cause is something perfectly natural with no magic, aliens or conspiracies involved. Best of all, their explanation is better than a hypothesis (to use the correct term for all the other evidence-free notions) because it is now backed by evidence. In the true scientific meaning of the word 'theory', the scientific theory now explains the observable facts, is supported by evidence and is theoretically falsifiable.

The rigs themselves are composed of rings of fresh, lush eelgrass growing on a sediment-covered chalk bedrock. Eelgrass extends its range essentially by cloning. Vegetative shoots extend in the sediment and produce new plantlets. The scientists have discovered that the sediment in the inner parts of the rings contains toxic levels of sulphide which, in a normal environment combine, with iron to become harmless. On these chalk bedrocks however, there is a lack of iron so the sulphides remain and build up in the sediment. The sulphides are produced by bacterial action on agricultural runoff. Only the mature plants can endure these levels so a ring forms as the plants are unable to invade the toxic sediment.

Distinct ‘fairy rings’ consisting of narrow fringes of eelgrass (Zostera marina L.) expand radially over a bottom of chalk plates outside the calcium carbonate cliffs of the island of Møn, Denmark. We conducted a survey to evaluate possible explanations for the formation of the rings and, more specifically, for the apparent die-off of eelgrass shoots on the inner side of the rings. The fairy rings were up to 15 m in diameter consisting of 0.3- to 1-m-wide zones of sea grass shoots at densities of up to 1,200 shoots m−2 and rooted in an up to 10-cm-thick sediment layer. On the outer side, shoots expanded over the bare chalk plates. On the inner side, shoots were smaller, had lower absolute and specific leaf growth, shoot density was lower and the sediment eroded leaving the bare chalk with scattered boulders behind. Sediment organic matter and nutrients and tissue nutrient contents were not different among positions. Sediment pools of acid volatile sulfides and chromium-reducible sulfur increased from outer to the middle positions of the rings, and so did total sulfur content of eelgrass tissues, while tissue δ34S isotope ratios, regardless of position in the fringes, were low reflecting substantial invasion of sulfide from the sediment. Neither the clonal growth pattern of eelgrass, sediment burial of shoots, hydrodynamic forcing nor nutrient limitation could explain the ring-shaped pattern. We conclude that the most likely explanation must be found in invasion of eelgrass shoots by toxic sulfide accumulating in the sediment due to low iron availability in the carbonate-rich environment.

Jens Borum, Ane Løvendahl Raun, Harald Hasler-Sheetal, Mia Østergaard Pedersen, Ole Pedersen, Marianne Holmer;
Eelgrass fairy rings: sulfide as inhibiting agent; Marine Biology February 2014, Volume 161, Issue 2, pp 351-358

A similar phenomenon can be seen in the fungal 'fairy rings' common in grasslands and sometimes hundreds of years old and so large they can only be seen in aerial photographs.

The explanation for these is perfectly natural. The fungus in the soil spreads outwards by extending fungal threads called hyphae which, when the conditions are right give rise to the familiar toadstools as fruiting bodies. The inner part of the ring becomes denuded of nutrients as they are used up so the hyphae which survive are those which extend outwards from the centre of the ring. Meanwhile, this fungal activity in the soil improves grass growth by releasing nutrients for the plants or by forming a symbiotic relationship with grass roots, so the grass where this activity is going on, i.e in the newly colonized soil, appears lush and greener. Other fungi may kill the grass or retard its growth but the result is the same - a ring in which toadstools appear.

He wha tills the fairies' green
Nae luck again shall hae:
And he wha spills the fairies' ring
Betide him want and wae.
For weirdless days and weary nights
Are his till his deein' day.
But he wha gaes by the fairy ring,
Nae dule nor pine shall see,
And he wha cleans the fairy ring
An easy death shall dee.

Traditional Scottish poem
But before people understood how this works, the rings appeared as if by magic and the magic rings were 'proof' that something magical was happening. The magic in this case being provided by fairies and so the rings were 'proof' of fairies.

In both these examples the 'proof' of magic lacked just one thing: whatever it was which was assumed to be causing it, and for which the rings were claimed as 'proof', had never been seen. There was no independent evidence to suppose they existed in the first place so there was no reason to include them in the explanation.

Using the phenomenon as 'proof' that a supposed cause exists without first proving that cause actually exists is an example of circular reasoning. It is including the conclusion in the reasoning leading to that conclusion. Circular reasoning and the false conclusions to which it usually leads (it is always possible that the conclusion was right by accident) is the cause of religions and the reason why no two religions ever agree. I would go so far as to say that all arguments for gods are circular for the simple reason that there is no definitive, authenticated evidence that any god has ever existed. Almost all theists are perfectly happy to accept that a lack of evidence for any but their own god is sufficient reason to assume they don't exist which is why they never include those gods in any explanations. The objective isn't to arrive at the truth but to confirm their assumption and so close the circle.

Humans like easy explanations and circular reasoning neatly provides an explanation whilst obscuring the false logic and ignoring the lack of evidence in the first place. The easy answer is all the evidence many people require and they will cling to that easy answer often in the face of contradictory evidence. The contradiction becomes a mere test of faith and great store can be placed in the skill by which it is dismissed.

This is exploited again and again by religious apologists who argue that the locally popular god must have caused the Universe, produced the appearance of design or made the Universe the way it is, therefore the Universe, 'design' or the way the Universe is are proof of the locally popular god. What they never do is establish a priori that the locally popular god exists in the first place and so including it in the explanation was valid. The important thing is to provide the audience with 'confirmation' that their easy answer was valid, so keeping the money from book sales and guest appearances rolling in.

This is the simple reason why every single time scientists have objectively examined any unexplained phenomenon they have failed to find any magic or supernatural explanation to be necessary. Every gap in which theology formerly sat a god has been found by science to be empty when examined, and the gaps, and the gods which occupy them, are getting daily smaller and smaller.

And this circular false logic leads people to kill other people and to deny basic human rights to people and to relegate whole populations and entire genders to second-class status and to tell themselves this is a good thing to do.

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