The Hellenic Navy (HN) (Greek: Πολεμικό Ναυτικό, Polemikó Naftikó, abbreviated ΠΝ) is the naval force of Greece, part of the Greek Armed Forces. The modern Greek navy has its roots in the naval forces of various Aegean Islands, which fought in the Greek War of Independence. During the periods of monarchy (1833–1924 and 1936–1973) it was known as the Royal Navy (Βασιλικόν Ναυτικόν, Vasilikón Naftikón, abbreviated ΒΝ).The total displacement of all the navy's vessels is approximately 150,000 tons.The motto of the Hellenic Navy is "Μέγα το της Θαλάσσης Κράτος" from Thucydides' account of Pericles' oration on the eve of the Peloponnesian War. This has been roughly translated as "Great is the country that controls the sea". The Hellenic Navy's emblem consists of an anchor in front of a crossed Christian cross and trident, with the cross symbolizing Greek Orthodoxy, and the trident symbolizing Poseidon, the god of the sea in Greek mythology. Pericles' words are written across the top of the emblem. "The navy, as it represents a necessary weapon for Greece, should only be created for war and aim to victory."...............The Hellenic Merchant Marine refers to the Merchant Marine of Greece, engaged in commerce and transportation of goods and services universally. It consists of the merchant vessels owned by Greek civilians, flying either the Greek flag or a flag of convenience. Greece is a maritime nation by tradition, as shipping is arguably the oldest form of occupation of the Greeks and a key element of Greek economic activity since the ancient times. Nowadays, Greece has the largest merchant fleet in the world, which is the second largest contributor to the national economy after tourism and forms the backbone of world shipping. The Greek fleet flies a variety of flags, however some Greek shipowners gradually return to Greece following the changes to the legislative framework governing their operations and the improvement of infrastructure.Blogger Tips and Tricks
This is a bilingual blog in English and / or Greek and you can translate any post to any language by pressing on the appropriate flag....Note that there is provided below a scrolling text with the 30 recent posts...Αυτό είναι ένα δίγλωσσο blog στα Αγγλικά η/και στα Ελληνικά και μπορείτε να μεταφράσετε οποιοδήποτε ποστ σε οποιαδήποτε γλώσσα κάνοντας κλικ στη σχετική σημαία. Σημειωτέον ότι παρακάτω παρέχεται και ένα κινούμενο κείμενο με τα 30 πρόσφατα ποστς....This is a bilingual blog in English and / or Greek and you can translate any post to any language by pressing on the appropriate flag....Note that there is provided below a scrolling text with the 30 recent posts...Αυτό είναι ένα δίγλωσσο blog στα Αγγλικά η/και στα Ελληνικά και μπορείτε να μεταφράσετε οποιοδήποτε ποστ σε οποιαδήποτε γλώσσα κάνοντας κλικ στη σχετική σημαία. Σημειωτέον ότι παρακάτω παρέχεται και ένα κινούμενο κείμενο με τα 30 πρόσφατα ποστς.........

Wednesday, April 23, 2014

'Ocean quack sound' solved..[ 4073 ]

Mystery of 'ocean quack sound' solved

Rebecca Morelle By Rebecca Morelle Global science correspondent, BBC News
23 April 2014 Last updated at 00:01 GMT
 
Antarctic minke whale  
The bizarre noise was first heard 50 years ago but now scientists say the Antarctic minke whale is its source
The mystery of a bizarre quacking sound heard in the ocean has finally been solved, scientists report.
The noise - nicknamed "the bio-duck" - appears in the winter and spring in the Southern Ocean. However, its source has baffled researchers for decades.
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Now acoustic recorders have revealed that the sound is in fact the underwater chatter of the Antarctic minke whale.
The findings are published in the Royal Society journal Biology Letters. 
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Lead researcher Denise Risch, from the US National Oceanic and Atmospheric Administration (Noaa) Northeast Fisheries Science Center in Massachusetts, said: "It was hard to find the source of the signal.
"Over the years there have been several suggestions... but no-one was able to really show this species was producing the sound until now."
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If it quacks like a duck
The strange sound was first detected by submarines about 50 years ago. Those who heard it were surprised by its quack-like qualities.



Antarctic Minke whale The researchers attached acoustic monitoring tags to the whales to eavesdrop on them
The researchers do not yet know under what circumstances the minke whales make their distinctive vocalisations, although the sounds that were recorded were produced close to the surface and before the mammals made deep dives to feed.
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The team says solving this long-standing mystery will help them to learn more about these little-studied animals.
Dr Risch said: "Identifying their sounds will allow us to use passive acoustic monitoring to study this species. 
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"That can give us the timing of their migration - the exact timing of when the animals appear in Antarctic waters and when they leave again - so we can learn about migratory patterns, about their relative abundance in different areas and their movement patterns between the areas."
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The team will be analysing data from the PALAOA station, the Alfred Wegener Institute's (AWI) permanent acoustic recording station in Antarctica, which has been recording in the Southern Ocean continuously in the last few years.
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This is not the only acoustic puzzle that scientists have recently shed light on
Another baffling low frequency noise - called The Bloop - turned out to be the sound of Antarctica's ice cracking.
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