The tide gauge of Marseille, a historical monument at the bedside of the Mediterranean Sea

If the km 0 of the French maps is at the foot of Notre-Dame, in Paris, the altitude zero is, she, in Marseilles, in the entrails of the tide gauge, a historical monument become watchdog for the Big Blue, of which she has taken the pulse for over 130 years.

When Mont Blanc is measured in September at 4808.72 m altitude, 1 cm less than in 2015, it is compared to the average level of the Mediterranean Sea. A level officially defined on January 1, 1897 by the tide gauge of Marseilles, in the cove Calvo, along the Corniche.

"If the first measurement dates from February 3, 1885, it is only after 12 years of observation that was officially set this level zero, "says AFP Alain Coulomb, engineer at the IGN, the National Institute of Geography and Forestry Information.

 The tide gauge dating from the 19th century (AFP - BERTRAND LANGLOIS)

The tide gauge dating from the 19th century (AFP – BERTRAND LANGLOIS)

On January 1, 1897, a bronze rivet covered with platinum and iridium is sealed right next to the well where the copper float tide gauge "measures" the sea. At exactly 1,661 m above the water level. It is in relation to this "fundamental landmark" that are now calculated all the altitudes in the hexagon, with nearly 400,000 "terminals" already scattered across the country, and 1,500 new ones installed each year.

– Switzerland measured in Marseilles –

These measurements are made in France, but also in Switzerland, which, due to a lack of coastline, has been attached to Marseille to define its zero altitude. But not in Corsica, where the unevenness is calculated by the tide gauge of Ajaccio, nor in the departments or territories of overseas, which also have their own measures.

 The engineer Alain Coulomb shows the tide gauge (AFP - BERTRAND LANGLOIS)

The engineer Alain Coulomb shows the tide gauge (AFP – BERTRAND LANGLOIS)

Classified historical monument in 2002, with the villa which hosts it, inhabited by a guardian until 1988, the tide gauge of Marseille is unique. If it is one of the few float mechanical tide gauges still to exist, "it is the only one in the world to understand an integrator, a totalizing part allowing to read constantly the average level of the sea over a given period", The Foundation for Heritage, which has just launched a call for donations to renovate the building, with nearly 10,000 euros already collected.

Second since 1998 by a system of notched wheels in the field of high-precision watchmaking. a digital camera, which calculates the sea level via a radar wave, the old Marseilles tide gauge remains useful for climatologists and scientists, as a witness to climate change.

– Climate change –

 C is thanks to the tide gauge that we know for example that the Mediterranean rose by 16 cm since 1987 (AFP - BERTRAND LANGLOIS)

It is thanks to the tide gauge that we know for example that the Mediterranean has been mounted 16 cm since 1987 (AFP – BERTRAND LANGLOIS)

Only device to "measure" the Mediterranean for 130 years, it is thanks to the tide gauge that we know for example that the Mediterranean has risen 16 cm since 1987, and that it is 15 cm lower than the Atlantic Ocean … "It is an inestimable inheritance of Marseillaises and Marseillais, an exceptional tool and unique in the world", insists Renaud Muselier, the president of the region Paca, who has just pledged to finance the part of the 60,000 euros of necessary works that would not be covered by the call for donations.

If the astronomical tides, caused by the Moon, can vary the level of the Great Blue from 30 to 40 cm, the difference may exceed one meter with meteorological tides, due to highs or lows.

 The tide gauge calculation method (AFP - BERTRAND LANGLOIS)

The method of calculating the tide gauge (AFP – BERTRAND LANGLOIS) [1 9659006] But no question of changing the official zero of French maps, frozen since 1897. The interest of the tide gauge is mainly to measure the impact of climate on the sea level. This led to the observation that the rise in The Mediterranean has accelerated, and was 25% faster between 2005 and 2015 than in the previous decade.

"With climate change, there is no longer any question of the usefulness of these measures. and the utility of the Marseilles tide gauge ", explains Alain Coulomb.

A sea of ​​plastic 3 times larger than France

This is a pile of wastes lost in international waters and whose responsibility is rejected by all countries. The eighth continent is an immensity of plastic that took place in all ocean s. Mainly located in the North Pacific, these waste soups are also present in the Indian Ocean, South Pacific, North Atlantic and South Atlantic. The formation located in the North Pacific, between Hawaii and California, is the best known and the largest.

According to a study published in the journal Scientific Reports Thursday, March 22, 2018, the size of this vortex would be 4 to 16 times higher than what the previous research suggested. This single zone would measure approximately 1.6 million km 2 which is three times the size of France, according to the researchers. By estimating that a square kilometer contains more than a kilo of plastic, the researchers concluded that this gigantic dump, also called "Great Pacific Garbage Patch," contains 80,000 tons of waste floating and non-compact mass. In total, the explorers estimated that no less than 1800 billion pieces of plastic floated in this magma. And it increases according to them " exponentially ".

Plastic represented 99.9% of the waste collected during the study. But contrary to what they imagined, the researchers were surprised to discover that more than three quarters of the debris found in this vortex was more than 5 cm. Previous research had shed more light on microplastics. Confiding in AFP, Laurent Lebreton, one of the main authors of the study and member of the foundation Ocean Cleanup says that all these results represent " rather good news because the large debris are much easier to collect than micro-plastics "

Consumer Society

Captain Charles Moore first discovered this plastic plate in 1997. It is It is composed of microplastics less than 5 millimeters in size and large objects up to 50 centimeters. This agglomeration of waste is formed by the movements of water, called ocean gyres. The pressure of the currents and the weak winds favor their progressive enlargement. 80% of this waste is of human origin (the production of plastic exceeds 320 million tons per year).

This is primarily waste generated by tourism: picnic remains, packaging of drinks, butts or beach games. The discharge of wastewater also causes urban waste to the seas and oceans. But much of the waste found in the waters also comes from fishing: they are residues of nets, ropes or traps. " People see the amount of fishing gear and point the finger at the fishing industry, but they also eat fish explains Laurent Lebreton to AFP. It's not the question of a sector or a region is mainly our way of life and consumption, disposable plastics, the all-disposable society "

The Ecosystem in danger with the "ghost fishing"

The first victim of this pollution oceanic is the animal species. Sea turtles are the most sensitive to waste. Very often they choke on plastic bags that they confuse with jellyfish. It is also the leading cause of death for this marine species.

Animals can also become entangled in all fishing materials found at sea or in the oceans. Seals and sea lions are particularly affected by entanglement. This phenomenon dubbed "ghost fishing" is also a significant risk for the conservation of the fish stock in certain areas. It causes a significant economic loss. Nets or ropes also cling to coral reefs and break them up.

Microplastics are ingested by fish. Thus, debris is transformed by the effect of salt, sun and water movements and become similar to plankton for marine animals, causing their intoxication, stocking or drowning. These micro-plastics are also great sponges because they capture all pollutants. By eating intoxicated fish, humans therefore absorb polluted plastics in spite of himself.

The hunt for plastics

To fight against this eighth continent, many initiatives are being put in place. With more funding than expected, the Ocean Cleanup Project could see the light of day this year instead of 2020. " These results provide us with key data to develop and test our cleaning technology, but it also emphasizes the urgency of tackling the problem of plastic pollution ", said through a statement Boyan Slat, founder of Ocean Cleanup. The 23-year-old Dutch is developing a system of about 30 floating barriers, each one to two kilometers long, between Hawaii and California. These barriers will have to block the waste. They will be attached to a floating anchor 12 meters long that will evolve in the water at the mercy of currents, just like plastic waste. This invention would clean about half of the North Pacific in 5 years. But these barriers can not pick up pieces smaller than one centimeter, which does not solve the problem of micro-plastics.

Another association, Sea Cleaner plans to create a sailboat of 70 meters long, 49 meters wide and 61 meters high, capable of collecting up to 600 cubic meters of plastic waste in contaminated areas. The navigator Yvan Bourgnon, the initiator of the project, was able to present it at the COP22, in Marrakesh, Morocco. To fund this project, which he named the Manta project, Yvan Bourgnon launched a participatory campaign to call for universal consciousness. In a few weeks, the financial goal was reached. A first prototype of 1 / 10th will be launched in the course of the year 2018. This test will be designed to refine and test the system of the waste collector. According to Yvan Bourgnon, a hundred Manta would be needed to collect all the plastic plates of the 8th continent.

7th or 8th continent?

Very long nicknamed 7th continent, this gigantic dumping plastic floating in different oceans , was reclassified to the rank of 8th continent after the discovery, in February 2017, of a possible new continent. The latter named Zealandia is located in the east of Australia, in the south-west Pacific. This land mass is larger than India. It is submerged at 94% under about 1,100 m of water. This discovery would imply that New Zealand, New Caledonia and a few other small islands are only parts of one single entity of nearly 5 million square kilometers.

The "peace channel": a crazy project to save the Dead Sea

" Only the sea can fill the sea ," said Moussa Salim al-Athem, who came to dig his tomato plants near Ghor al-Haditha, south of the Dead Sea . Born in 1953, this farmer jordan has seen the blue waters retreat over the years, revealing a lunar landscape of gaping craters and salt sculptures. " Before 1967, the water was ten minutes walk from home, now it takes an hour ," he says.

A treasure that dries up

Spectacular ] salty lake lined with red ocher cliffs the Dead Sea is threatened with extinction. It has lost a third of its surface since 1960 and continues to decline by more than one meter per year. In question, intensive potash operations, which accelerate its evaporation, but especially the decrease in the flow of the Jordan River, increasingly exploited by the two countries it borders, Jordan and Israel . " Since 1950, the flow of the Jordan has dropped from 1.2 billion cubic meters to less than 200 million ," said Frédéric Maurel, expert engineer of the French Development Agency (AFD). A disaster for the Dead Sea and its residents: Jordanians, Israelis and Palestinians

Because with its medicinal black muds, its exceptional salinity, its potash reserves, its tourist attraction, " the Dead Sea has a historical, biblical, natural, tourist, medical and industrial value, making it an invaluable treasure argues Avner Adin, Israeli water specialist. Ideas to stop its decline have not failed. Around 1900, the founding father of Zionism Theodor Herzl had already thought of digging a canal to feed it from the Mediterranean. It is finally the project of an aqueduct leaving from the Red Sea and entirely built on the Jordanian territory which was retained, with the signature in December 2013 of a tripartite agreement between Israelis, Jordanians and Palestinians. Regional collaboration bringing hope to this historically troubled region. This agreement initially plans to pump 300 million m 3 seawater, desalination in a dedicated plant north of the Jordanian port of Aqaba to obtain drinking water that is sorely lacking in the region, and to transfer desalinated brines via a pipeline into the Dead Sea, 200 km to the north.

Not enough to stabilize the level of the Dead Sea, but an early solution to curb its drying out, says Frédéric Maurel, in charge of this project for AFD. " There should also be a more economical use of water, both in agriculture and in the potash industry ," he says. In 2015, agreements also provided for reciprocal water sales: Jordan would deliver Israel's drinking water south, which in return would increase its sales of water from the Sea of ​​Galilee to supply Northern Jordan . And the Palestinians would also receive additional water deliveries from Israel. At the end of 2016, five consortia of firms were pre-selected

"Last impetus"

Remains the question of the financing of this public-private partnership, valued at 1 billion dollars, of which 400 million public funds. Some 120 million donations have already been pledged, notably by the United States and Japan. AFD has set up a European group of donors (France, Italy, Spain, the European Union and the European Investment Bank) willing to lend $ 140 million at advantageous rates to Jordan. " We have never been so close to the goal, it misses the last impulse of the Jordanian and Israeli authorities ", stresses Mr. Maurel.

For a diplomatic source in Amman, " project remains essential for the countries of the region Difficult to bring tourists around a salt pool ". But " it remains subjected to the diplomatic vagaries ". The talks were totally frozen after the death in July of two Jordanians killed by an Israeli security officer at the Israeli embassy in Amman. They would be restarting after Israel apologized in mid-January. " In my opinion, the main obstacle could be financial ," judge Avner Adin. Israel, which is also expected to contribute $ 140 million to the project, has not yet confirmed this commitment. In Amman, we are determined to move forward, with or without Israel. " It's a question of national security ," said the secretary general of the Jordan Water Authority, Iyad Dahiyat. " Our groundwater is overexploited, water desalination is Jordan's future, and for us, the Red Sea-Dead Sea project is essential ".

Tapping into the Red Sea to Revive the Dead Sea

Tapping into the Red Sea to Produce Drinking Water and Save a Dead Sea Threatened with Dewatering? Jordan, Israel and the Palestinians' project of "peace channel" has never been so close, despite uncertainties.

"Only the sea can fill the sea", says Moussa Salim Al-Athem came to dig tomato plants near Ghor al-Haditha, south of the Dead Sea. Born in 1953, this Jordanian farmer has seen the blue waters retreat over the years, revealing a lunar landscape of gaping craters and salt sculptures.

"Before 1967, the water was ten minutes walk from my house, now it takes an hour," he says.

 Project MER roe 8 moor SEA (AFP - Sophie RAMIS)

Project MER rOUGE 8 SEA (AFP – Sophie RAMIS)

Spectacular salt lake bordered with red ocher cliffs, the Dead Sea is threatened with extinction: it has lost a third of its surface since 1960 and continues to fall more than one meter a year.

In question, intensive potash operations, which accelerate its evaporation, but especially the decrease in the flow of the Jordan River, increasingly exploited by the two countries bordering Jordan and Israel.

"Since 1950, the flow of the Jordan has dropped from 1.2 billion cubic meters to less than 200 million," said Frédéric Maurel, expert engineer of the French Development Agency (AFD).

A disaster for the Dead Sea and its residents: Jordanians, Israelis and Palestinians

– The dream of The odor Herzl –

Because with its medicinal black mud, exceptional salinity, potash reserves, and tourist appeal, "the Dead Sea has historical, biblical, natural, tourist, medical and industrial value, which makes an invaluable treasure, "argues Avner Adin, an Israeli water specialist.

Ideas to halt its decline have not failed. Around 1900, the founding father of Zionism Theodor Herzl had already thought of digging a canal to feed it from the Mediterranean.

It is finally the project of an aqueduct starting from the Red Sea and entirely built on the the Jordanian territory that was retained, with the signing in December 2013 of a tripartite agreement between Israelis, Jordanians and Palestinians. Regional collaboration bringing hope to this historically troubled region

First, it plans to pump 300 million cubic meters of seawater, to desalinate it in a dedicated plant in the north of the Jordanian port of Aqaba. to obtain desperately needed drinking water in the area, and to transfer desalinated brines through a pipeline into the Dead Sea, 200 km to the north.

Not enough to stabilize the level of the Dead Sea, but a the beginning of a solution to curb its drying up, underlines Frédéric Maurel, in charge of this project for AFD. "There should also be a more economical use of water, both in agriculture and in the potash industry," he says.

In 2015, agreements also provided for reciprocal water sales: Jordan would deliver Israel's drinking water south, which in return would increase its sales of water from the Sea of ​​Galilee to supply the North from Jordan. And the Palestinians would also receive additional water supplies from Israel.

At the end of 2016, five consortia of companies were shortlisted.

– "Last impetus" –

Remains the question of financing this public-private partnership valued at $ 1 billion, including $ 400 million in public funding.

Some 120 million donations have already been pledged, including by the United States and Japan. AFD has set up a European group of donors (France, Italy, Spain, the European Union and the European Investment Bank) willing to lend $ 140 million at advantageous rates to Jordan.

"We did not never been so close to the goal, it lacks the last push of the Jordanian and Israeli authorities, "says Maurel.

For a diplomatic source in Amman," this project remains essential for the countries of the region. tourists around a salt puddle ". But "it remains subject to diplomatic vagaries".

The talks were thus totally frozen after the death in July of two Jordanians killed by an Israeli security officer at the Israeli embassy in Amman. They would be restarting after Israel apologized in mid-January.

"In my opinion, the main obstacle could be financial," Judge Avner Adin said. Israel, which is also expected to contribute $ 140 million to the project, has not yet confirmed this commitment.

In Amman, one appears determined to move forward, with or without Israel.

"It's a question of national security," said the secretary general of the Jordan Water Authority, Iyad Dahiyat. "Our groundwater is overexploited, water desalination is Jordan's future, and for us the Red Sea-Dead Sea project is essential."

In Le Havre, an old landfill drops waste to the sea

State and local authorities will soon launch a study to try to find a solution to an old dump of Le Havre that discharges "between 30 and 80 m3 per year" of waste in the sea, was learned Friday from the city hall.

The public authorities "agreed at a meeting on Thursday" that it was necessary to update an existing study by evaluating the various possible solutions with the corresponding financial figures ", explained to a correspondent of AFP Marc Migraine, deputy LREM to the mayor of Le Havre in charge of nature in the city The elected official had no details on the launch date of the study

In 2011, a first study was launched at the initiative of the town hall on this old dump of "about 400,000 tonnes of waste", known locally as Dollemard. "The document raised technical barriers and a significant cost to extract waste," said Migraine, indicating "that the scenario of a regular collection was finally retained by the city."

For a complete extraction of the waste and the restoration of the site, the study, which the AFP could consult, counted on a cost excluding tax between 17 and 21.5 million euros. And she pointed, among others, the risk of "destabilization of the cliff" in case of excavation.

Meanwhile, according to Jean-François Samson, the Sea Shepherd Association Le Havre, we find waste Dollemard " to Boulogne-sur-Mer or, closer, in the heart of the natural reserve of the estuary of the Seine ".

"The implementation of a final solution will take time," admits Marc Migraine. But the city of Le Havre has "without waiting to make the decision to strengthen the measures of collection."

"The file returned to the table on the occasion of the last storm Eleanor," said Samson. The beach was covered with trash, and local ecologists are back on the track. "We can not continue this way, we must find a lasting solution to this problem," said Alexis Deck, EELV city councilor in the city of Le Havre.

Solicited, the sub-prefecture of Le Havre did not wish to do of comments at this stage.

Historical dump of the city of Le Havre, the site closed at the end of the 90s. According to the city, "80% are inert and the remaining 20% ​​are, essentially, constituted of scrap and plastics. "