June 20, 2011
Higher emissions of carbon dioxide in the atmosphere could have a devastating effect on coral reefs by the end of the century.
A group of scientists reached that conclusion after studying three sites on the ocean floor in Papua New Guinea, which have acidic conditions similar to those believed to exist in the oceans of the planet in less than 100 years.
The sites studied are leaking volcanic fissures in the ocean allowing exhaust gases, creating a more acidic. These are truly "natural laboratory" that make it possible to predict the future impact of one of the greatest threats to corals, ocean acidification.
By increasing the acidity around the leak, corals accused drastic changes. "We could only see a few species and was not present any of the more structurally complex, which are most important to fish," he told the BBC one of the study's authors, Chris Langdon, an expert on corals of the Rosenstiel School of Science Marine and Atmospheric University of Miami.
There were still forming corals near the leaks, but ultimately on the Porites species, which resemble in appearance to large stones and branches lack the characteristics of other species.
The three dimensional structure of the reef is offering an opportunity for many fish species live and take refuge there.
About a third of emissions of carbon dioxide in the atmosphere are absorbed by the oceans. When CO2 enters the ocean, reacts with sea water, producing carbonic acid, increasing its acidity.
The research adds to growing evidence of the need for a rapid transition to a future with less CO2 emissions "
Rising carbon dioxide emissions, mainly from burning fossil fuels, have caused ocean acidification, a 30% increase compared to preindustrial levels, causing the pH of surface waters of the oceans has dropped 0, 1 units.
PH is a logarithmic scale, so each number represents variation large-scale variations. A change of one pH unit means an increase of 10 times.
The acidification of the oceans also produces a reduction in the amount of so-called carbonate ions in water, which many marine animals need to form skeletons and shells.
The pH in the infiltration of Papua New Guinea is 7.8, a level considerably more acidic than the industry average of 8.1 for the world's oceans.
The leaks are probably the closest we have to simulate the impact of increased emissions of carbon dioxide in coral. Let us see what happens to the complex interactions among species in terms of increased acidity
The research adds to growing evidence of the need for a rapid transition to a future with less CO2 emissions, if we want to minimize the risk of large losses in coral reefs
The study also found that a pH of 7.7 stops the formation of all types of corals.
Another major threats facing coral reefs is the increase in ocean temperatures that can cause them to lose their pigmentation when the algae die of feeding. The phenomenon is known as coral bleaching.
The study included, besides Chris Langdon, scientists at the Institute for Marine Mammals of Australia and the Max Planck Institute for Marine Microbiology in Germany.
The research results were published in the June issue of the journal Nature Climate Change
June 19, 2011
"It's like a carpet of cat vomit, as acid as the acid in our stomachs. You can clone themselves, reproduce exponentially and have no natural predators. If they hurt, their parts are regenerated and if they are short in half, creating two living beings. "
The speaker's animal science journalist Ben Gilliland is a tunicate or sea squirt Didemnum vexillum called and known as "vomit of rock."
It is, in his words "as an invader of a movie from the '50s science fiction."
Gilliland is not the first nor the only one to refer to this sea creature in such terms, but although it is appropriate marine areas in various parts of the world, what is this well-deserved prestige?
Ascidians have probably been around since about 500 million years.
They are found in all oceans of the world, living in the stillness of a shell or a rock.
They have few natural enemies and how they can reproduce sexually or asexually, exponentially, are theoretically immortal.
The tunicate begins life as a tadpole larva type, eyes, heart and a rudimentary spine.
When you find your home, clinging to a suitable surface and undergoes metamorphosis into an animal becomes barrel-shaped form, which immediately begins to produce clones of himself.
In short - and here is where the science-fiction film has already gelatinous form a broad sheet of several square meters to create their own dead zones in the seabed.
But these areas are they really dead?
Death called dead zones acreditadaLas not represent usually the result of oxidation of huge amounts of organic matter, which causes a complete depletion of oxygen and makes the area an absolutely inappropriate for typical marine life.
"Many bacteria and archaea may be reproduced, even in these difficult conditions. Tunicates can not survive in dead areas, are more the symptom, appear in abundance when large amounts of organic matter, but only to a point."
So that sea squirts are just opportunistic animals that take advantage of the large amount of food available and by no means the cause of these dead zones.
According to Dr. Monteiro da Cruz Lotufo, the real cause of these dead areas are probably contamination.
The visibility of ascidians is preceded by its ability to reproduce abundantly and in very difficult circumstances.
However, their presence in marine ecosystems is rather modest "and that there are good competitors for the substrate, such as algae, sponges and corals," he told BBC Esplá Dr. Alfonso Ramos, Department of Marine Sciences and Applied Biology, University of Alicante, Spain.
However, some invasive species of sea squirts can pose a real threat, says Dr. Monteiro da Cruz Lotufo
"We are in many areas, mainly in fishing and the cultivation of shellfish (mussels, oysters, clams), because they can grow very quickly and may not have a predator in the area to control the growth of their population naturally."
Monteiro da Cruz Lotufo for "sea squirts are but another example of invasions that result from human agency, that is, by transporting the bodies to areas where none existed, attached to the hulls of boats or on water ballast ".
"Furthermore, the ascidian capture plankton microalgae, digests and transforms the rest in feces. This 'waste' is the power supply, first of microorganisms and detritivorous animals like worms, gastropods and crustaceans," says Monteiro da Cruz Lotufo.
"They do not represent damage to the marine ecosystem," says Dr. Ramos Esplá. "They are a pest because it hurt us as human beings."
Corella minuta. The tunic of ascidians has properties that can help in the fight against cancer.
Some reconstructions of evolutionary history as sea squirts places closest living relatives to vertebrates.
Some of the approximately 2,500 species of sea squirts are sought after food in many countries, especially Japan, Korea, China, Chile and France.
In addition, according to Dr. Ramos Esplá, "are active and very efficient filter feeders. The large species (usually not exceeding 25 centimeters) can filter about 200 quarts a day, so water purifiers are excellent, particularly in ports ".
Apart from its scavenging activity, many ascidians are bioengineer, is capable of creating environments for other species in the cell coat, or tunic, that protects them.
The tunic itself of these animals have chemical properties that make it attractive for the study of human health, as we said Dr. Ramos Esplá.
"The robe has antimitotic substances, ie, blocking cell division. Hence, these substances are being studied in order to treat some types of cancers," he says.
Both experts consulted by BBC agreed that the sea squirt is far from being the global threat that is sometimes attributed to him.
A beautiful sea monster that does not deserve the smear campaign
June 14, 2011
June 11, 2011
1-The Sharks can lose up to 1000 teeth per year. These are constantly replaced throughout their life.
2-The great white shark, star of many films, weighs about 4,000 kg, equivalent to 4 medium-sized cars, and can measure up to 10 m long.
3-The Sharks have a super sense of smell, almost perfect. Chemicals detected in water over long distances, so they can "smell" blood in the water.
4 - Is the cure of cancer in sharks?
This disease takes so long to haunt us could have a possible cure in sharks. Studies indicate that the spiny dogfish (Squalus acanthias) contains a substance that could inhibit tumor growth by cutting the blood supply.
5-The mouth of the whale shark can measure 2 feet wide, although it usually feeds on tiny plankton.
6-When you rub the skin of a shark from the tail to the head is extremely rough, as it is composed of dermal denticles, made of same material as the teeth. Historically, many cultures were using shark skin as sandpaper.
7-The Sharks have the ability to learn behaviors qualified. In the scenario of an aquarium, have been conditioned to respond to colored targets to receive food.
8-Many sharks can see colors. In addition to its superb view, most of them have very acute hearing and smell. They have a unique sensory ability to detect electric currents, using gel-filled pores called ampullae of Lorenzini
9-The spiny dogfish shark is one of the longest-living, reaching between 70 and 100 years old.
10-Sharks have no bones in the body. Their skeletons are made of cartilage.
11-The scales are also highly specialized, are like teeth, with enamel and dentin, which makes them very hard. Instead of being located one above the other as in most fish, sharks are next to each other.
12-Something that characterizes sharks over all fish is its "face." If you notice, most of the fish's mouth in the middle of the tube, without protruding nose. But sharks are the mouth and nose protrusion below which gives that aspect so characteristic.
13-The whale shark is the world's largest fish. Can reach up to 18 m in length.
The title of "man-eater" is headed: the bull shark (Carcharhinus leucas), tiger shark (Galeocerdo cuvieri) and shark (Carcharodon carcharias).
The fastest shark that inhabits the seas is the mako (Isurus oxyrinchus) has shown that it can go faster than 35 km / h
14-The Shark Cigar is the world's smallest. It measures only 50 cm as an adult, it feeds your mouth adhering to the skin of large fish.
15-The curious shape of the hammer head shark is an advantage for this shark, keep your eyes on the ends of the head may have a broad vision.
16-The swim, in that they are also a few specialists. For example the rear fin, if the view is much bigger up side, this allows them to dive at high speed to boot.
June 5, 2011
A team of scientists has detected for the first time in a mine in South Africa, multicellular organisms in the deeper layers of the terrestrial biosphere. The study, published in the latest issue of the journal Nature, provides a new perspective on the richness and diversity of life on the planet's surface.
So far, however, scientists thought that multicellular creatures could not live in this environment due to high temperatures, lack of oxygen and space that occur at great depths. The team geologist from Princeton University (USA) Tullis Onstott has revealed several nematode worms, including a hitherto unknown species (called "Halicephalobus mephisto"), between 0.9 and 3.6 miles below the surface, in a crevice formed by water inside a mine.
These creatures, which are about half a millimeter, at high temperatures, so they reproduce asexually and feed mainly on bacteria.
The Carbon-14 tests indicate that the crack in the nematodes were found was formed between 3,000 and 12,000 years. The research results indicate that the ecosystems on Earth's surface are more complex than what was accepted until now, and can lead to significant implications in the search for life on other planets.