A Kiwi has led the first mission to visit the famed shipwreck RMS Titanic in 14 years.
Expedition leader Rob McCallum of EYOS Expeditions says the wreck is slowly succumbing to the sweeping eddies as well as natural salt corrosion and metal-eating bacteria.
The Titanic, which lies in 3800m deep water about 330 nautical miles off the coast of the Newfoundland, Canada, sank on April 14 and 15, 1912, killing 1500 who were on board.
McCallum said with the help of a submersible, they held five successful dives over a 10-day period from July 29.
However, before they kicked off, the crew held a memorial service on the deck of the DSSV Pressure Drop, which is equipped with the world's only unlimited depth [11,000m] submersible, laying a wreath over the side in honour of those who died.
As well as the submersible, the ship was also equipped with four tender boats and three deep water "landers" - devices used for communication, tracking and transporting material to and from the surface.
McCallum, who has spent an entire career working in the undersea world, said he felt privileged to be able to lead another expedition to the famed wreck.
"This is the first dive that anyone has done since our last dive in 2005. No one has seen the Titanic since and so we were anxious to check in and to monitor her condition, work with scientists who have monitoring stations onside and to assist with the filming of a new documentary."
But getting to the site and into the bitterly cold, -1C, water, was challenging.
"She is very difficult to reach because of the logistics of working at 12,500ft while 370 miles offshore are challenging. A lot of people would like to do, but diving on the Titanic is a complex and difficult undertaking, with currents up to four knots.
Despite his dive having more than 200 dives notched up, they couldn't take anything for granted.
"We plan every dive from scratch, and it is an immense honor and responsibility to have returned to the Titanic after so many years."
During their last dive in 2005, 200 dives were undertaken using twin Mir Russian submersibles, which were rated to 6000m and carried a pilot and two guests.
"Until now only 157 clients have had the opportunity to dive on the Titanic, but many films and documentaries have been produced for a variety of international broadcasters."
In 2010, the wreck was scanned with high-resolution sonar using a remote operated vehicle.
Researchers also placed scientific experiments near the wreck to conduct research.
"Many of the experiments centre around metallurgical samples, which are sacrificial pieces of metal that researchers use to track the breakdown of metal at these depths.
"The information is useful in predicting how shipwrecks break down over time.
"In addition, scientists monitor the biology around the wreck which serves as a large artificial reef."
A team of experts and scientists also examined the remains of the Titanic capturing 4k footage for the first time and photogrammetry to assess the wreck's current condition and project its future.
Their work will be published while a documentary film is being made by BAFTA and Emmy award-winning Atlantic Productions London.