The seafloor is dissolving, thanks to human activity

Carbon emissions are dissolving the seafloor, especially in the Northern Atlantic Ocean.

Shown here, Azkorri beach in Basque Country in northern Spain.

Credit: Iñaki Bolumburu

From New Atlas by Michael Irving

Excess carbon dioxide isn't just building up in the atmosphere – the oceans are holding onto more of the stuff too, fizzing them up like soda. As the seas get warmer and more acidic, all kinds of havoc is wrought, and now a new study has identified yet another symptom.
Researchers at Princeton and McGill Universities have found that the seafloor is beginning to dissolve as a result of human activity.

A research vessel investigating the effects of human-created carbon dioxide emissions on the seafloor, which is found to be dissolving at an increased rate

(Credit: Robert Key)

According to the Smithsonian's Ocean Portal organization, about 525 billion tons of CO2 has been absorbed by the world's oceans since the beginning of the industrial era, making seawater up to 30 percent more acidic than it was 200 years ago.
That makes it the fastest known change in ocean chemistry in 50 million years or so, and the effects have already been devastating.

A map of the parts of the ocean that are experiencing the most extreme seafloor dissolution, thanks to carbon dioxide emissions

(Credit: McGill University)

Ocean acidification is contributing to coral bleaching, upsetting predator/prey relationships, messing with the survival instincts of fish, and even dissolving certain sea creatures.
And now we have a new problem to add to the ever-growing list: pockets of acidic water are reaching the bottom of the ocean and destroying the seabed.

A healthy seafloor is made mostly of calcite, which comes from the decomposed remains of plankton and other sea creatures.
But increased CO2 levels are quickly ramping up the acidity and eating away at the calcite.
In the worst hit areas, such as the Northern Atlantic and the southern oceans, the normally chalky-white material is becoming a muddy brown color.

The new study investigated the extent of the dissolving seafloor, and how much blame belongs to human influence.
Basically, the deepest parts of the sea are already fairly acidic, thanks to higher pressure, lower temperature and stored CO2.
But closer to the surface, conditions are less hostile, meaning calcium carbonate particles will accumulate on the seafloor at shallower depths.
The point where the two transition is called the calcite compensation depth (CCD).

Oceanic Carbon Cycle, Credit: IPCC

This depth is one of the main metrics of seafloor dissolution, since anything below that point will dissolve.
The study examined recent databases of bottom-water chemistry and other conditions in the western North Atlantic Ocean, and found that the CCD there has risen by about 300 m (984 ft) since the beginning of the industrial era.

In the lab the team recreated the seafloor at different depths, to get a better understanding of what factors influence the dissolution of calcite.
By modeling and comparing the rates of seafloor dissolution from preindustrial and modern times, the team was able to calculate the amount that can be classed as human-induced. In the Northern Atlantic, this was between 40 and 100 percent.

"For decades we have been monitoring the increasing levels of anthropogenic carbon dioxide as it moves from the atmosphere into the abyssal ocean," says Robert Key, co-author of the study.
"While expected, it is none the less remarkable that we can now document a direct influence of that process on carbonate sediments. It will be really interesting to see if we can further support this result with new data generated by autonomous floats in the Southern Ocean."

The next steps for the team are to model the seabeds based on predictions of future carbon dioxide scenarios, to determine how fast seafloors might be dissolving over the next few centuries.

The research was published in the journal Proceedings of the National Academy of Sciences.

Links :

• Princeton Univ : Human activities are dissolving the seafloor
• McGill Univ : Alterations to seabed raise fears for future
• NexusMedia : The Seafloor is Disappearing
• Gizmodo : Human Carbon Emissions Are Dissolving the Ocean Floor
• NASA : Carbon cycle 
• EPA : Understanding the Science of Ocean and Coastal Acidification
• Medium : Trouble at sea: what carbon dioxide emmisions are doing to our oceans
• GeoGarage blog : Ocean acidification : the other CO2 issue / Oceans face massive and irreversible impacts without carbon cuts / Ocean acidification is deadly threat to marine life ... / Acidifying ocean threatens California coast 

Norway (NHS) layer update in the GeoGarage platform

125 nautical raster charts have been updated and 2 new insets added

see GeoGarage news

First World War shipwrecks mapped in online project by the Maritime Archaeology Trust

This viewer contains the accumulated research - including photos, geophysics, and video - on the wrecks and sites from the project.

From WorthingHerald by James Connaught

The Forgotten Wrecks of the First World War interactive map – a huge, new online First World War resource – has been launched.

The interactive map connects researchers to information, images, documents, 3D models and videos about more than 1,100 First World War shipwrecks and archaeological sites off the south coast of England.

Diving on SS Alaunia, a requisitioned passenger liner turned troopship which struck a mine in October 1916

This new resource brings together the results of the Maritime Archaeology Trust’s, Heritage Lottery funded Forgotten Wrecks of the First World War project.
The four-year project, coinciding with the centenary of the Great War, investigates the vital, yet little known, struggle that took place on a daily basis, off the south coast of Britain.
It tells extraordinary stories of the war: stories of the ships, their crews and their communities.

Bathymetric image of HMHS Warilda, a hospital ship which was torpedoed in August 1918, killing 223 including 101 patients

Through a programme of fieldwork, research, exhibitions and outreach, and bringing together personal and family histories, with archival and archaeological research, the project records these fragile and largely overlooked sites and builds a clear picture of the nature and scale of this aspect of the war.

Together these sites highlight the people and vessels from across the world drawn into the conflict off Britain’s coast: the everyday extraordinary.
For between 1914 and 1918 shipwrecks were ‘everyday’ events.
There are just under 1,200 sites in the project area alone.
These sites include 1,130 wrecks, as well as 39 coastal sites.

Among them are ocean liners, merchant vessels and fishing trawlers, seaplane lighters, airships, submarines, troop and hospital ships.
There are naval and commercial ships, steam and sail.
There are ports and harbours, seaplane bases, wireless stations, quays, jetties and piers.

 HMHS Asturias

The scale and variety of this First World War maritime archaeology reflects the singular importance of the war at sea.
Britain’s merchant fleet kept the country running during the war and everything necessary for that war, from troops and munitions to materials and intelligence, moved by sea.

The Forgotten Wrecks project is itself huge: 1,200 sites including 62 fieldwork sites, 200 new geophysical images, more than 700 artefacts recorded and 44 exhibitions with over half a million visitors.

All of this work has been possible because of the 322 volunteers and the 1,821 volunteer days they have contributed to the project.

Now the results of all of that research – geophysical images, dive videos of the wrecks, artefacts, historical photographs, 3D models and virtual underwater tours of sites, as well as site reports – and the extraordinary stories of these wrecks are available through the interactive map.

This unique and important new resource for researchers, family historians and the public is accessible for free through the Forgotten Wrecks project website

Links :

• BBC news : Interactive map reveals World War One wreck sites / WW1 shipwrecks pictured by sonar off Welsh coast
• Centenary news : 'Forgotten Wrecks of the First World War' charted in new online resource
• Exmouth Journal : Wartime airship crash off Exmouth coast revealed in new online map
• Porthmouth : Remembrance Day 2018: How WW1 warship HMS Caroline survived the greatest battle of all
• National Geographic : How World War I launched mapmaking at National Geographic 

Rhum : only victory is pretty

Francis Joyon's Idec Sports in Pointe-à-Pitre.

At 62, Francis Joyon won the 11th edition of the Route du Rhum at the helm of IDEC-Sport, a maxi-trimaran that has now won the queen of transats three times since 2010 with Franck Cammas and 2014 with Loïck Peyron.

Four years ago, it took Peyron 7 days, 15 hours and 8'32''.

Reference time planed by Joyon (7 d. 14h28'55'') but also by François Gabart (Macif), who arrived 7'8'' after him.

( L. Venance/AFP)

From L'Equipe by

Francis Joyon and François Gabart had an epic duel in the final hours of the transatlantic race, sailing at each other's sight, before Joyon won the race.
 With a new record at stake.

 Joyon - Gabard : an anthology arrival

It was in an exceptional nightly finale, full of suspense, that the 11th edition of the Route du rhum ended with the victory of Francis Joyon, just a few hundred metres ahead of François Gabart.

 Macif arrival

The decision was made in the very last hours, the last few minutes.
This was a timely revival of the nautical legend, that of the arrival of the original Route du Rhum in 1978, whose outcome had been established around 98 seconds between Mike Birch and Michel Malinovsky after 23 days at sea. (see "Seule la victoire est jolie")
But when the appearance of the little Olympus-Photo behind Kriter V took place in a good swell forty years ago, all sails filled, the victory of this edition was decided at night, in a very light wind where tactics and manoeuvring intelligence took on their full meaning.

 photo : Alexis Courcoux

With less than a mile to go (less than two kilometres), the two boats were about two hundred metres apart, putting the two skippers almost within earshot before Joyon made the decisive tack and won the race at 4:22 am in mainland France.

To be aware of Joyon's huge comeback (in red) on Gabart (in blue) in the last eight hours a few miles from the finish of the RDR2018 for an extremely tight finish
courtesy : Tracking GeoRacing RDR2018

An exceptional suspense

For most of the 2018 race, which started on 4 November from Saint-Malo, François Gabart had nevertheless led the race on Macif, his Ultimate class sailboat, with Francis Joyon in his wake, despite having relegated him to 165 miles in the heart of the Atlantic.
But in the last few hours, as we approached the West Indies, Francis Joyon made an exceptional comeback.

On Sunday, while the Idec Sport skipper was less than 15 miles away, we learned that François Gabart had lost a foil and then a rudder during his crossing, which explains his increasing difficulties in maintaining the gap with his pursuer.

Weather 4D R&N view with Arome weather forecast model

courtesy of Francis Fustier

The two competing skippers then had to go around Guadeloupe from the west and then return north to reach the finish line opposite Pointe-à-Pitre.
It was in this windless western zone that Joyon first managed to get back within one nautical mile (1.8 km).



At dusk, the two sailboats could see each other in the distance, while the transatlantic was transformed into a coastal regatta.
At the last buoy, on this chickly coast in a breeze, Macif crossed the mark 17 minutes ahead of Idec Sport.
Shortly afterwards, however, François Gabart managed to regain some steady wind, while Francis Joyon found himself dragging a locker line on his starboard rudder.

 Francis Joyon before his change of tack which placed him in front of François Gabart

The two skippers almost side by side in the ascent to the finish line

[#RDR2018]
Incroyable finish !! Les deux bateaux sont bord à bord à moins de 1 mille de l'arrivée !

📷 : Yvan Zedda / MACIF pic.twitter.com/ZY8gATBePp

— trimaranMACIF (@trimaranMACIF) November 12, 2018

 Last tack
then 428 seconds for eternity...

Links :

• SailWorld : Joyon snatches record-setting victory in thrilling finale to Route du Rhum-Destination Guadeloupe / Transatlantic Triumph for Joyon
• B&G : Ultime-8 victory for Francis Joyon, by Mark Chisnell
• GeoGarage blog : Route du Rhum 2018, 40 years of legend

Into the dark: Russian Navy frogmen break russian record with 416m dive

Three Pacific Fleet frogmen broke the Russian Navy’s diving record and brandished the national flag as they descended 416 meters into the Sea of Japan during a thrilling underwater rescue training exercise.The experienced divers had to spend three days in a compression chamber before they could begin the journey into the dark void using a diving bell, operating from the Igor Belousov navy rescue ship, the Defense Ministry reported on Tuesday.

During their mission, the frogmen surveyed the area and practiced connecting oxygen lines to a submarine model.
The men also unfurled the Russian flag to celebrate their record-breaking dive.
The previous record of the Russian Navy was set last year when the same squad descended 317 meters. 
(from RT news) 

However, the record openwater dive in the Mediterranean led to COMEX’s record experimental saturation dive in 1992.

COMEX Hydra 10, Hyperbaric Experimental Centre, Marseille, France, 1992.
The dive protocol required a four-week pre-dive period, two days confinement at 10 m (33 ft), 13 days to compress to 675 m (2,215 ft) breathing hydro-heliox (a.k.a. hydreliox) (hydrogen 49%, helium 50% and oxygen 1%), and three days of bottom stage between 650 m and 675 m.
One of the divers, Théo Mavrostomos, then moved into a separate chamber and continued to 701 m (2,300 ft) for a period of seven hours.
The record experiment required 24 days of decompression followed by 2.5 months post-dive monitoring.

The experimental dive followed COMEX’s Hydra 8 openwater record saturation dive in 1988.
Breathing a gas mixture of hydro-heliox (hydrogen 49%, helium 50% and oxygen 1%), it took four COMEX (Compagnie maritime d’expertises) divers, and two divers of the Marine Nationale (French Navy), eight days to compress inside a chamber to the maximum bottom pressure of 53 atmospheres (780 psi).

A total of six dives were conducted with a total of 28 hours of work at depths of 520 m (1,706 ft) and 534 m (1,752 ft).

Once at depth, the divers conducted pipeline connection exercises in open water.

After completing their assigned tasks, the divers re-entered the chamber for 18 days of decompression.

COMEX divers: Thierry Arnold, Régis Peilho, Patrick Raude, Louis Schneider.

Marine Nationale divers: Serge Icart, Jean-Guy Marcel-Auda

Note : the world record (deepest scuba dive in sea water) was set in 2014 by Ahmed Gabr to a depth of 332.35 m (1,090 ft 4.5 in) : took almost 15 hours of deco to reach the surface.