We have spoken of straws, describing their characteristics and the mechanisms which determine their growth, but our friend the speleologist Andrea Massagli, a guide at the Grotta del Vento and an enthusiast of macro photography, took some shots in the central area of the “first itinerary” which seem to put in discussion at least partly what was affirmed in the previous article. In photos 1 and 2 some highly enlarged details can be seen of a stalactite in the initial phase of its growth. It would appear to be the start of a soda straw, but instead of the classic ring of little crystals around a hole through which the water feeds it, a blanket of crystals can be noted which seem to block the hole.
More or less the same thing can be noted in photos 3, 4, and 5.
n° 3
n° 4
n° 5
In photo n°6 instead the start of the growth of a normal hollow straw can be seen where the selective competition is ongoing between only two crystals which surround the meatus for water supply.
n° 6
n photos 7 and 8 the classic ring of minute crystals can be seen which surround the start of the drop, giving way to the formation of new straws.
In the photo it cannot be seen clearly where the water that forms the formations comes from. It is possible that in the first five it comes from the outside, therefore the stalactite which is forming does not need a meatus for the water supply (they would not therefore be straws). In photos 6, 7 and 8 the water could be coming from leptoclases and therefore forming proper straws. LE CANNULE
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