Captured – SamaGamer

Headlamp on the head, the researcher Dominique Genty rushes several times a year, since 1992, in the kilometers of underground galleries of Villars, in the Dordogne, in the south-west of France to decipher the evolution of the climate. .Under a metal platform allowing tourists to admire the silhouettes of horses drawn 20,000 years ago or the magical spectacle of thousands of stalagmites, stalactites and other limestone veil flows, the Perigord paleoclimatologist shows two holes drilled during his research on “speleothems”, these mineral deposits of the underground environment. The cave contains invaluable information: the oxygen present in the infiltrated rainwater, accumulated and dissolved underground to form, over the millennia, limestone concretions , and carbon, from the succession of plants above the cave. By fixing the two elements, these stalagmites have “recorded” the climate of the past. “Their variation is linked to the abundance or not of vegetation at the above the cave, and as the presence of vegetation on the surface is directly linked to the climate, these elements inform us about its evolution”, summarizes this research director at the CNRS. engineer, the researcher thus explores European and North African caves to collect stalagmites, veritable “climatic archives”. Only the already broken concretions are cut with a diamond saw so as not to “destroy the aesthetics” of the places, close that observed by the first h**o sapiens.In his laboratory in Bordeaux, armed with a dental drill, the scientist then “samples” the calcite dust on the stalagmites collected. He inserts it into a mass spectrometer to measure the abundance of carbon isotopes and decipher “the climatic signal”. A similar tool, measuring uranium and thorium, makes it possible to date the sample going back up to 500,000 years. evolution of the local monsoons for 640,000 years.- Nuclear tests -In Villars, the chronological analysis of the carbon 14 (C14) content – a radioactive isotope of carbon – of the stalagmites made it possible to detect the impact of the peak of the nuclear tests carried out in the world during the Cold War.”The tests carried out at that time released a lot of C14 into the atmosphere”, which then infiltrated into living things, then, via rainwater, into underground stalagmites, according to the researchers. The peak of C14 measured in other caves of France, Slovenia and Belgium, intervenes each time in shift of several years after 1963, date of the treaty of Moscow which put an end to the nuclear tests in the atmosphere. This discovery “proves” that most of the carbon taken from the stalagmites was indeed the one previously present in the atmosphere and the vegetation, and serves as a “tracer” to better know the time of infiltration of water and carbon between the surface and the cave. It has made it possible to accredit the discipline, now in full swing with dozens of laboratories in Austria, Germany, France, United Kingdom, Australia, United States or China. With a longer dating, localized data, and a low shipping cost, research on cave “speleothems” completes the analysis of ice or marine cores, other memories of the climate, taken from the poles and the oceans.- Brutal changes -It reconstructs the major cycles in the history of the climate, between the glacial and interglacial periods, generated by the evolution of the parameters of the Earth’s orbit, and detects the abrupt variations within these cycles. “Technological progress” will allow also soon to “estimate the average temperatures” of distant times, bets Mr. Genty, by modeling a stalagmite in the cave in 3D, with a consumer application on his smartphone. To assess the current warming linked to human activity , the researcher has installed underground sensors since 1993, in order to measure the evolution of temperatures, water flow or CO2 content.35 meters underground, in an ultra-stable environment, the scientific duo updates the temperatures recorded on a laptop computer: 12.2°C against 11.1°C thirty years ago. An “enormous” increase in such a short time.”We have already experienced brutal changes” in the cycles of the past but “never such a rapid warming in an interglacial period”, as currently, observes Mr.

The shark that frequented the Miracle beach in Tarragona has finally been captured and transferred to the Aquàrium in Barcelona, where a specimen of the same species is found. Three Aquàrium technicians, supported by a Red Cross device, trapped it between two nets and immobilized it, taking advantage of the animal’s regularity in its behavior patterns, which every afternoon between 6 and 7 p.m. approached the Bank. Two of his captors suffered minor injuries.

Several sharks were sighted, for the first time, on the beach of l’Arrabassada in Cambrils, last month. The technicians have corroborated the presence of a second shark, of about 2 meters, and it is speculated that there may be a third. Despite this, the captured specimen, a female between 1.50 and 1.60 meters, is the only one that has approached the shore.

Initially, the animal was identified as a basking shark (Cetorhinus maximus), probably because this species, together with porbeagle and blue shark, is common in the Mediterranean. Nonetheless, Biologists from the Center for the Recovery of Maritime Animals (CRAM) of the Generalitat de Catalunya, later and unequivocally established the species to which the shark belongs, Carchainus Plumbeus, known as the milbert shark or gray shark.

Gray sharks, unlike basking sharks, tend to be aggressive and if they feel threatened they can tear off small pieces of meat with their pointed, triangular teeth. Their diet is based on small fish, mollusks and crustaceans, so that humans are not one of their objectives. Even so, and despite the fact that its size did not make the animal dangerous, there could be some doubts about the supposed harmlessness of the animal.

The shark demonstrated its zero fear of humans by swimming among the bathers in the early days. Fortunately, Tarragona City Council, took the precaution of temporarily prohibiting access to the stretch of Miracle beach that the animal considered his. However, the presence of the shark attracted large numbers of onlookers, and on four occasions unconscious people were fined 400 euros who ignored the recommendations by getting into the water.

Yesterday, in Tarragona, surveillance of the Miracle beach was kept until the night in case more sharks appeared. This morning it was considered that the bathroom could be reopened throughout the area. However, an investigation has been initiated to analyze the temperature and salinity of the water, as well as other underwater and surface elements in order to determine the causes why the shark came so close to the coast.

After the capture, the female gray shark is being tested to verify that it is healthy and it will even be checked if it is waiting for offspring. After studying the evolution of the animal in its captivity and finding answers to some questions, the intention is to take the animal to the high seas and release it.

The environmental organization Mediterrania-CIE and its Marine Surveillance group, has taken advantage of the current situation of shark sightings on our coasts, to present some data. For example the Mediterranean is home to hundreds of species of sharks, including the great white shark, the largest and most powerful marine predator. Most species live offshore, in the depths. When a shoreline intrusion occurs, it is always justified for some reason.

On the popular level, there are often misconceptions about sharks, for example, when they are compared to dolphins. While the latter are mammals, like whales or killer whales, sharks are fish, although it can be said that they are unique fish. In addition to its peculiar shape and behavior, its skeleton is made up of cartilage rather than bone. That is why they are called Cartilaginous Fish, a zoological group that also includes Rays and Chimeras. Still, they are vertebrates, since they have a backbone.

There are many myths regarding the aggressiveness of sharks and the danger they pose to humans, in part heightened by certain film productions. Some of the stories that are told are true, but not as horrifying as they are presented in certain books and action movies. Of the nearly 400 species of sharks that currently exist, only 20% are dangerous to humans.. In the Mediterranean, only two human shark attacks are added and none of them resulting in death.

Between the potentially dangerous species Noteworthy are the white shark (Carcharodon carcharias), the tiger shark (Galeocerdo cuvier), the bull shark (Carcharinus leucas) and the shortfin mako (Isurus oxyrinchus). Other species, which under certain circumstances, can attack as a defensive mechanism are the gray shark (Carcharinus plumbeus) or the blue shark (Prionace glauca). All of them, present in Mediterranean waters.

Despite the fascination with sharks, humans are largely to blame for their increasingly worrying regression. Mediterrania-CIE cites as causes of shark population decline the following:

the lack of food due to the overexploitation of species that are part of their diet (squid, tuna, sea bass, etc.)
the fishing of the sharks themselves to sell the fins in international markets such as China, Japan, Morocco or Senegal
accidental fishing due to drift or trawl nets used for fishing other species; pollution and the constant and accelerated destruction of the coastline that diminishes the quality of its habitat, its food resource and the ease of laying eggs or giving birth to young

Genciencia | Sharks in Tarragona