ARCHIVE 436 – NAUTILUS!!!

 

 


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Nautilus in the Blue Reef Aquarium, Newquay, Cornwall; 13 Sept 2011.

The exclamation marks in this post’s title are there for a reason. For much of the first half of my life I was an enthusiastic amateur and professional geologist. I found my first fossil – a brachiopod from the Carboniferous Limestone of the nearby Mendip Hills – when I was aged about five, and then proceeded to amass a large collection of rocks, minerals and fossils before leaving home to study geology at university, at the age of 18.

Having Somerset and (especially) Dorset as my boyhood collecting grounds, I soon had many examples of the multitude of fossil ammonites to be found there – and especially those from around Lyme Regis and Charmouth on what is now designated ‘The Jurassic Coast’. Despite their great abundance in the Jurassic period, ammonites have long since gone the way of the dinosaurs and none are to be found living today. However, ammonites are Cephalopods (“head-feet” >>> Google it!), and two groups of these molluscs are still living today.

First, there are the octopus, cuttlefish and squid. And, second, there still remain a very small number of species of Cephalopods which, just like the long extinct ammonites, have a coiled and chambered shell – and the overall name for these is Nautilus.

Nautilus shells are quite common in seaside giftshops, but I’ve never seen live ones before and I was, quite simply, captivated. From the photo you can see some Cephalopod characteristics – the large eyes and the tentacles that Cephalopods use to see and catch their prey. Once clasped by the tentacles, the prey is drawn in towards the sharp beak at the tentacles’ base – all Cephalopods are carnivorous. And if it is itself attacked, the individual above can withdraw its eyes, tentacles and other soft parts back within the shell, when the spotted shield above the eye comes down to seal the opening of the shell shut from predators.

The Nautilus in the Newquay aquarium were enthralling. They were completely impassive but, as I’m writing in Twitter, they were slowly rising and falling in the water like itinerant baubles on a Christmas tree! For the fact is that while the animal lives in the shell’s large, open, end chamber, the other, smaller chambers further back in the shell contain nitrogen which the animal can increase and decrease at will to provide bouyancy – and these in Newquay were doing just that – impassively moving vertically up and down in the water, and causing a faint click when they collided with the tank’s glass sides.

Incredible! Wonderful! And I’m just not sure that my photo does justice to these remarkable creatures >>> but there is just one more fact to mention. Cephalopods squirt a dark ‘ink’ into the water to deter predators – and when early attempts to improve the longevity of photographs resulted in the photographs becoming a brownish grey colour, this tone was called sepia after the colour of the ink produced by the common cuttlefish – which is scientifically classified in the genus Sepia.

Click onto the image to open a larger version in a separate window.

Technique: D700 with 24-120 Nikkor lens at 120mm; 6400 ISO; conversion to monochrome via Silver Efex Pro.
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CORNWALL 2 – THE BLUE REEF AQUARIUM AT NEWQUAY (2) – NAUTILUS!!!

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Nautilus in the Blue Reef Aquarium, Newquay;  13 Sept 2011.

The exclamation marks in this post’s title are there for a reason.  For much of the first half of my life I was an enthusiastic amateur and professional geologist.  I found my first fossil – a brachiopod from the Mendips’ Carboniferous Limestone –  when I was aged about five, and then proceeded to amass a large collection of rocks, minerals and fossils before leaving home to study geology at university, at the age of 18.

Having Somerset and (especially) Dorset as my boyhood collecting grounds, I soon had many examples of the multitude of fossil ammonites to be found there – and especially those from around Lyme Regis and Charmouth on what is now designated ‘The Jurassic Coast’.  Despite their great abundance in the Jurassic period, ammonites have long since gone the way of the dinosaurs and none are to be found living today.  However, ammonites are Cephalopods (“head-feet” >>> Google it!), and two groups of these molluscs are still living today.

First, there are the octopus, cuttlefish and squid.  And, second, there still remain a very small number of species of Cephalopods which, just like the long extinct ammonites, have a coiled and chambered shell –  and the overall name for these is Nautilus.

Nautilus shells are quite common in seaside giftshops, but I’ve never seen live ones before and I was, quite simply, captivated.  From the photo you can see some Cephalopod characteristics – the large eyes and the tentacles that Cephalopods use to see and catch their prey.  Once clasped by the tentacles, the prey is drawn in towards the sharp beak at the tentacles’ base – all Cephalopods are carnivorous.  And if it is itself attacked, the individual above can withdraw its eyes, tentacles and other soft parts back within the shell, when the spotted shield above the eye comes down to seal the opening of the shell shut from predators.

The Nautilus in the Newquay aquarium were enthralling.  They were completely impassive but, as I’m writing in Twitter, they were slowly rising and falling in the water like itinerant baubles on a Christmas tree!  For the fact is that while the animal lives in the shell’s large, open, end chamber, the other, smaller chambers further back in the shell contain nitogen which the animal can increase and decrease at will to provide bouyancy – and these in Newquay were doing just that – impassively moving vertically up and down in the water, and causing a faint click when they collided with the tank’s glass sides.

Incredible!  Wonderful!  And I’m just not sure that my photo does justice to these remarkable creatures >>> but there is just one more fact to mention.  Cephalopods squirt a dark ‘ink’ into the water to deter predators – and when early attempts to improve the longevity of photographs resulted in the photographs becoming a brownish grey colour, this tone was called sepia after the colour of the ink produced by the common cuttlefish – which is scientifically classified in the genus Sepia.

Nikon D700 with 24mm-120mm VR Nikkor at 120mm; 6400 ISO; conversion into monochrome via Silver Efex Pro.
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