Diver at 156

A CAIRNS dive instructor is reaching extreme depths on the Great Barrier Reef rarely seen before by human eyes.

Lance Robb, from Closed Circuit Divers at Kewarra Beach, has dived deeper than most on the world’s largest natural attraction.

He dropped down to an incredible depth of 156m – a new personal record – during a recent trip with James Cook University scientists searching for new life at Osprey Reef, about 90 nautical miles off Port Douglas.

The edge of the reef plunges to a depth of up to 1500m.

Proof our Great Barrier Reef is not covered in mud | Scientists search Great Barrier Reef for new species
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Mr Robb uses a special re-breathing apparatus to help him reach limits normally unsafe for humans.

The rebreather, which recycles exhaled gas while providing oxygen, has the advantage of not expelling any bubbles.

This allows for a stealth approach to diving, and the opportunity to see marine creatures normally scared away by regular diving apparatus.

On his extreme dive at Osprey in May, Mr Robb attempted to find eggs belonging to the nautilus, a deep-sea relative of the squid.

He also observed never-before-seen corals, and large silver-tip and grey reef sharks.

As he was adjusting his camera at 156m, a large grey reef shark swam straight at him.

“It probably speared down 50-60m down straight at me. It turned around about 1m away from me. It was straight at me, and then turned away,” he said.

When asked what thoughts were going through his head at that moment, he joked: “Nothing goes through your brain at that moment, it usually goes through your pants.”

The veteran diver of 37 years has logged about 6000 dives, including exploring the depths of Lake Eacham on the Atherton Tableland, where he has encountered giant barramundi

Nature’s hardest oddball has the most powerful punch on Earth, but it is stunning in other ways too, according to marine biologist JAMIE WATTS

You normally glimpse mantis shrimps retreating into crevices or running away, but this guy was cruising over the reef, a mix of curious self-assuredness and nervous hurry.
We were fulfilling a long-term dream of diving in the Lembeh Strait in Indonesia. It certainly lived up to the hype, and we had seen dozens of the strangest, most delightful little creatures in the world.

The mantis, often up to 30cm long, looks to have been built from odd-sized spare parts, yet it somehow flows together extremely well. This fluid glide over and around obstacles, punctuated by freezing to absolute stillness of everything but the huge, constantly rotating, stalked eyes, makes me think of Randall Boggs, Steve Buscemi’s chameleon-like amphibian from Monsters Inc.

SUPER VISION
The compound eyes are regarded as the most complex and capable eyes on Earth. Their three sections give trinocular vision with each eye – better than our binocular vision. The wide separation and independence of each eye not only doubles this to give the mantis six-way (sex-nocular!?) vision, but allows each set of three eyes to scan independently all around, while keeping incredible focus and acuity.  It doesn’t even end there. We see in three colours – basically red, green and blue – whereas the mid-band in each mantis-shrimp eyeball can see in 10 colours, including ultra-violet, infra-red and polarised light.

PUNCHING WELL ABOVE ITS WEIGHT
How mantis shrimps use this vision, or why they need it, is not totally understood. One reason is certainly a need to judge their legendary punch.  Mantis shrimps have the most powerful physical weapon for their size of any animal. Without precise distance estimation, the mantis could either yank off its own limbs by striking in front of a target, or smash them by punching through something excessively solid. The punch (a kick, if we’re being pedantic) of a mantis shrimp is 10 times faster than the strike of its land-based namesake, the praying mantis.  A mantis shrimp can punch at more than 50mph, with 150kg of force. This is about the same force as a fit young adult human can muster in a punch, but focused into a tiny point of contact.

Even more impressive is that this force is generated through water. The unfortunate victim gets hit twice – first by the blow, then by the shock wave from the speed of the punch instantly boiling the water. This shock wave can kill the prey even if the blow misses, and is powerful enough to emit a flash of light. The second leg – the punching leg – is rather like a human leg in build, with the power coming from the “thigh” muscle. The equivalent of the knee is tucked under the chin, and the “foot” is either a sharp-edged club or a series of long curved spines, depending on the species.
There are around 425 species of mantis shrimp, separated into “smashers” or “spearers” by their foot design. Either way, they have a latch between the thigh and the knee, building up tension in a curved leaf-spring before releasing the latch – and the punch.
Mantis shrimps are merciless and vicious in attack, with smashers pummelling the shells of crabs and snails to pieces, and spearers shooting out their wickedly elegant long limbs to impale fish and cuttlefish.

A COMPLEX LIFE
There is, however, a more sophisticated side to these creatures. The vivid purple and blue target painted on the tail-fan of the commonly seen Indo-Pacific peacock smashing mantis hints at another reason for that incredible vision.  Because they fight over a limited supply of small living space, and over mates, and because of their incredible ability to do damage, like many aggressive animals mantis shrimps need a mechanism to make sure that each fight does not necessarily end in death.
So they literally give each other a vividly painted target on their tail-shield to attack – they can then strike a strong-enough blow to give a clear indication of strength without having to kill each other. They sometimes even bluff, holding out the flaplike antenna scales to startle off another mantis, even when they are newly moulted and soft-bodied.

Unlike other crustaceans, mantis shrimps have large brains, long lives (up to 40 years) and complex behaviour, including recognising individuals, courtship and elaborate ritualised fights over mates.
At least in the case of Lysiosquillina maculata, a giant spearer and the largest mantis shrimp, occasionally exceeding 40cm in length, this behaviour extends to long-term monogamous relationships. No other invertebrates have such complex behaviour.

Many of us tend to think of mantis shrimps as tropical, but they are surprisingly abundant in cooler waters. The Med has a fishery for one spearer, and at least one smaller version of the giant tropical spearer is not uncommon around western and southern coasts of the UK.  Rissoides desmaresti lives in burrows on sandy bottoms, and has been seen over extensive areas off Wales in particular. The size of a king prawn, apparently our resident spearer is every bit as pugilistic as its larger tropical cousins.

Diver Joe Lepore steadies a heavy 17th-century cannon as it’s lifted by an airbag from the seafloor near the mouth of Panama‘s Chagres River (see map) in a recently released picture taken in 2010.

The newly recovered cannon is among six believed to have belonged to the fleet of 17th-century buccaneer Capt. Henry Morgan, whom later accounts painted as a bloodthirsty pirate.

In 1671 Captain Morgan’s current flagship, Satisfaction, hit a rocky reef and sank as he sailed out of the mouth of the Chagres River en route to sacking the Panama Viejo, now called Panama City.

Three more of Captain Morgan’s ships either slammed into the same reef or collided with each other and also went down. But the determined Welsh privateer reassembled what remained of his fleet and continued on to plunder the city. Privateers were private sailors under contract to states—in Captain Morgan’s case, Britain.

In 2008 an international team of archaeologists found the ships—and their cannons—that sank on that disastrous day. In 2010 the scientists began bringing cannons and other artifacts to the surface, where they’ll be treated to remove organic buildup and then displayed in Panama.

(See exclusive pictures: “Blackbeard Pirate Relics, Gold Found.”)

The project was a collaborative effort that included the government of Panama, the Waitt Institute for Discovery, the National Oceanic and Atmospheric Administration (NOAA), Texas State University, and the National Geographic Society. (The Waitt Institute sponsors the Waitt Grants Program for the Society, which also owns National Geographic News.)

—Willie Drye

PROVIDENCE, Rhode Island — Ocean Opportunity, a Rhode Island based not for profit organization, is pleased to announce the safe and successful return of an expedition to explore and document the natural history of the mesophotic, or ‘middle light’, zone from 200 to 500 feet in the Exumas, Bahamas from April 28 through May 8th. The project was hosted at the John H. Perry Jr. Caribbean Research Center – a facility synonymous with a long lineage of advancements in marine technology and innovations in ocean exploration.

This expedition built upon the team’s previous successes in a November project on Andros, Bahamas in which the team worked to 430 feet – more than 3 times the depth of conventional scuba diving. The expeditions are being led by Explorer Michael Lombardi, who has been funded by the National Geographic Society to carry out the work.
Collaborators on this recent expedition included individuals from the American Museum of Natural History, the City University of New York, the University of Connecticut, and the University of Kansas.

The deep diving team (including Jeff Godfrey of UConn and NGS/Waitt Grantee Michael Lombardi) conducted several mixed-gas closed circuit rebreather dives in excess of 300 feet, with one to 400 feet, and another reaching 446feet. These explorations allowed the team to observe, firsthand, below the presumed sealevel at the end of the Pleistocene ice age, some 370 to 420 feet below today’s sea level. Numerous images, samples, and specimens were gathered which are being evaluated by project collaborators.

When asked ‘why work to the frontier limits of manned exploration?’, Lombardi states, “The reaction time, real-time decision making, and personal interaction offered by wet diving at these depths, as opposed to robotics use, brings the raw and intimate experience of human exploration back into the game. Nearly 70 years of marine science has been fueled by the ability to routinely access the shallow coral reef ecosystems – that excitement, and creativity made possible by a researcher actually being there catalyzed the marine science field that we know today. We are on the verge of creating an opportunity for the next 70 years. This is a very exciting time for benthic marine scientists.”