Much of the water on Earth and elsewhere in the solar system likely predates the birth of the sun, a new study reports.
The finding suggests that water is commonly incorporated into newly forming planets throughout the Milky Way galaxy and beyond, researchers said — good news for anyone hoping that Earth isn’t the only world to host life.
“The implications of our study are that interstellar water-ice remarkably survived the incredibly violent process of stellar birth to then be incorporated into planetary bodies,” study lead author Ilse Cleeves, an astronomy Ph.D. student at the University of Michigan, told Space.com via email. [Theories on the Origin of Life]
“If our sun’s formation was typical, interstellar ices, including water, likely survive and are a common ingredient during the formation of all extrasolar systems,” Cleeves added. “This is particularly exciting given the number of confirmed extrasolar planetary systems to date — that they, too, had access to abundant, life-fostering water during their formation.”
Astronomers have discovered nearly 2,000 exoplanets so far, and many billions likely lurk undetected in the depths of space. On average, every Milky Way star is thought to host at least one planet.
Water, water everywhere
Our solar system abounds with water. Oceans of it slosh about not only on Earth’s surface but also beneath the icy shells of Jupiter’s moon Europa and the Saturn satellite Enceladus. And water ice is found on Earth’s moon, on comets, at the Martian poles and even inside shadowed craters on Mercury, the planet closest to the sun.
Cleeves and her colleagues wanted to know where all this water came from.
Microscopic Bubbles Baffle Ocean Scientists:
The most abundant photosynthetic organism in the world throws countless small sacs in the oceans , which could be having a dramatic impact on marine ecosystems , according to a new study. These sprouts contain microbial proteins and genetic material , which may influence the growth of other marine microbes and even protect against viruses.
The oceans are the largest ecosystem in the world , and unicellular cyanobacteria organisms that obtain their energy through photosynthesis – are the keystone group . A type of cyanobacteria, Prochlorococcus is the most abundant in the world, numbering in the billions of billions of billions photosynthetic organism . These tiny organisms account for about 10 % of all photosynthesis on Earth, forming the base of the food chain and provides the atmosphere with oxygen . Researchers at the Massachusetts Institute of Technology (MIT ) , led by biological oceanographer Sallie Chisholm found that cyanobacteria may play an even greater role in the ecosystem than previously thought .
The team reports that Chisholm cyanobacteria secrete small vesicles, membrane-enclosed sacs into the surrounding ocean. Chisholm first observed vesicles in 2008 when one of his graduate students , Anne Thompson , spotted small buds on the surface of Prochlorococcus under an electron microscope. ” The vesicles , which called them” Chisholm recalled, ” like little bubbles. ” A couple of years later, MIT postdoctoral Steven Biller proposed that these vesicles may be vesicles, based on their resemblance to the vesicles of other species. This was confirmed by isolation of the vesicles and further examination under the electron microscope. The vesicles were at least as abundant as the bacteria themselves .
These initial observations were made in bacteria grown in the laboratory and may not necessarily apply to wild microbes. Therefore, Biller tactics , collecting hundreds of liters of seawater off the coast of Massachusetts, and from the Sargasso Sea near Bermuda. Vesicles found in these samples as those of laboratory cultures . Analysis of the contents of the blebs revealed a variety of biological molecules : proteins, DNA , and RNA . DNA sequencing revealed that it was a variety of microbes , not only Prochlorococcus . Therefore, these vesicles appear to be a general feature of the marine microorganisms .
Because they are so abundant , and because they contain various biomolecules, these vesicles are a major source of organic carbon , nitrogen, and phosphorus in which other organisms can feed . Indeed , Chisholm and colleagues showed that no other photosynthetic bacteria, can grow using vesicles of cyanobacteria as their sole carbon source . ” That’s kind of neat ,” says Marvin Whiteley , a microbiologist at the University of Texas, Austin, who was not involved in the study. “What really changes the way we think about marine ecosystems and how they are created and how nutrients are provided . ”
Another important consequence of this finding is that , in the words of Biller, “It’s kind of asking a lot more questions than it answers . ” Perhaps the new bigger question is why the bacteria produce these vesicles in the first place . The authors offer some hypotheses . First, cyanobacteria live benefit from other types of bacteria . Vesicles provide food for other bacteria encourage this living arrangement . Moreover, because the vesicles containing the DNA, can facilitate the exchange of genetic material between individual bacteria , a process known as horizontal gene transfer . The last and perhaps most interesting , the vesicles may help defend against viruses. Chisholm group showed that when known to attack virus cyanobacteria are mixed with vesicles , the virus will bind to vesicles and to infect them appear as if the vesicles were living cells. Therefore, the authors speculate that these vesicles may function as cellular decoys , distracting the virus from infecting cyanobacteria .
Whatever their purpose , these vesicles show that we still have much to learn about life in the oceans. ” We did not set out to study this,” Chisholm says, “but Prochlorococcus is always putting things in front of us to study.
TEPCO estimated that between 20 trillion and 40 trillion becquerels (units of radioactivity representing decay per second) of radioactive tritium have since leaked into the ocean:
In lieu of the Japanese government doing the right thing and finally coming clean about the epic environmental catastrophe that is Fukushima, which it hopes to simply dig under the rug even as the inconvenient reality gets worse and thousands of tons of radioactive water make their way into the ocean, one is forced to rely on third-party sources for information on this tragedy. We present a useful primer from Scientific American on Fukushima “water retention” problem and “what you need to know about the radioactive water leaking from Japan’s Fukushima nuclear plant into the Pacific Ocean.”
Radioactive Water Leaks from Fukushima: What We Know
Scientists on both sides of the Pacific have measured changing levels of radioactivity in fish and other ocean life since the March 2011 earthquake and tsunami triggered a nuclear meltdown at Japan’s Fukushima Daiichi nuclear plant. On Aug. 2, 2013, when Japan’s Tokyo Electric Power Co. (TEPCO) gave its first estimate of how much radioactive water from the nuclear plant has flowed into the ocean since the disaster, the company was finally facing up to what scientists have recognized for years.
“As an oceanographer looking at the reactor, we’ve known this since 2011,” said Ken Buesseler, a marine chemist at the Woods Hole Oceanographic Institute in Woods Hole, Mass. “The news is TEPCO is finally admitting this.”
TEPCO estimated that between 20 trillion and 40 trillion becquerels (units of radioactivity representing decay per second) of radioactive tritium have leaked into the ocean since the disaster, according to the Japanese newspaper Asahi Shimbun. The Fukushima plant is still leaking about 300 tons of radioactive water into the ocean every day, according to Japanese government officials. [Infographic: Inside Japan’s Nuclear Reactors]
Japan is haunted by two lingering questions from this aftermath of the disaster: First, how the radioactivity might seriously contaminate ocean life that represents a source of seafood for humans; second, whether it can stop the leaks of radioactive water from the Fukushima plant.
Radioactivity is not created equal
The Fukushima plant is leaking much less contaminated water today compared with the immediate aftermath of the nuclear meltdown in June 2011 — a period when scientists measured 5,000 to 15,000 trillion becquerels of radioactive substances reaching the ocean. Even if radioactivity levels in the groundwater have spiked recently, as reported by Japanese news sources, Buesseler expects the overall amount to remain lower than during the June 2011 period.
“The amount of increase is still much smaller today than it was in 2011,” Buesseler told LiveScience. “I’m not as concerned about the immediate health threat of human exposure, but I am worried about contamination of marine life in the long run.”
The biggest threat in the contaminated water that flowed directly from Fukushima’s reactors into the sea in June 2011 was huge quantities of the radionuclide called cesium. But the danger has changed over time as groundwater became the main source for leaks into the ocean. Soil can naturally absorb the cesium in groundwater, but other radionuclides, such as strontium and tritium, flow more freely through the soil into the ocean. (TEPCO is still coming up with estimates for how much strontium has reached the ocean.)
Tritium represents the lowest radioactive threat to ocean life and humans compared with cesium and strontium. Cesium’s radioactive energy is greater than tritium, but both it and tritium flow in and out of human and fish bodies relatively quickly. By comparison, strontium poses a greater danger because it replaces the calcium in bones and stays for much longer in the body.
Not fishing for trouble
A number of fish species caught off the coast of the Fukushima Prefecture in 2011 and 2012 had levels of cesium contamination greater than Japan’s regulatory limit for seafood (100 becquerels per kilogram), but both U.S. and Japanese scientists have also reported a significant drop in overall cesium contamination of ocean life since the fall of 2011. The biggest contamination risks came from bottom-dwelling fish near the Fukushima site.
The radioactive groundwater leaks could still become worse in the future if TEPCO does not contain the problem, U.S. scientists say. But they cautioned against drawing firm conclusions about the latest impacts on ocean life until new peer-reviewed studies come out.
“For fish that are harvested 100 miles [160 kilometers] out to sea, I doubt it’d be a problem,” said Nicholas Fisher, a marine biologist at Stony Brook University in Stony Brook, N.Y. “But in the region, yes, it’s possible there could be sufficient contamination of local seafood so it’d be unwise to eat that seafood.”
The overall contamination of ocean life by the Fukushima meltdown still remains very low compared with the effects of naturally occurring radioactivity and leftover contamination from U.S. and Soviet nuclear weapons testing in the 1960s. Fisher said he’d be “shocked” if the ongoing leaks of contaminated water had a significant impact on the ocean ecosystems.
Source of radioactive water
TEPCO is facing two huge issues in stopping the radioactive water leaks. First, groundwater from nearby mountains is becoming contaminated as it flows through the flooded basements of the Fukushima plant’s reactor buildings. The water empties into the nuclear plant’s man-made harbor at a rate of about 400 tons per day — and TEPCO has struggled to keep the water from leaking beyond existing barriers into the ocean.
“This water issue is going to be their biggest challenge for a long time,” said Dale Klein, former head of the U.S. Nuclear Regulatory Commission. “It was a challenge for the U.S. during Three Mile Island [a partial nuclear meltdown in Pennsylvania on March 28, 1979], and this one is much more challenging.”
Second, TEPCO must also deal with contaminated water from underground tunnels and pits that hold cables and pipes for the Fukushima nuclear plant’s emergency systems. The underground areas became flooded with highly radioactive water during the initial meltdown of the Fukushima plant’s reactors, and have since leaked water into the ocean despite TEPCO’s efforts to seal off the tunnels and pits.
TEPCO has also been racing to deal with the problem of storing hundreds of thousands of tons of radioactive water from the Fukushima plant, said Hiroaki Koide, a nuclear engineer at Kyoto University in Japan. The Japanese utility is testing a water decontamination system called ALPS that can remove almost all radioactive substances except for tritium, but has put much of the contaminated water in storage tanks in the meantime.
“The tanks are an emergency solution that is not suitable for long-time storage,” Koide said. “Water will leak from any tank, and if that happens, it will merge with the groundwater.”
What must be done
So what solutions exist beyond building more storage tanks? Klein reviewed a number of possible solutions with TEPCO when he was picked to head an independent advisory committee investigating the Fukushima nuclear accident.
One possible solution involves using refrigerants to freeze the ground around the Fukushima plant and create a barrier that stops the inflow of groundwater from the mountains. TEPCO is also considering a plan to inject a gel-like material into the ground that hardens into an artificial barrier similar to concrete, so that it can stop the contaminated groundwater from flowing into the ocean.
Such barriers could help hold the line while TEPCO pumped out the water, treated it with purification systems such as ALPS, and then figured out how to finally dispose of the decontaminated water.
“My priority would be stop the leak from the tunnel immediately,” Klein said. “Number two would be to come up with a plan to stop the inflow and infiltration of groundwater. Number three is to come up with an integrated systematic water treatment plan.”
Meanwhile, both Japanese and U.S. scientists continue to gather fresh scientific data on how the radioactivity impacts ocean life. Despite low contamination levels overall, studies have shown great differences in certain species depending on where they live and feed in the ocean.
“The most straightforward thing the Japanese can do now is measure the radionuclides in fish tissue, both at the bottom of the ocean and up in the water column at different distances from the release of contaminated groundwater,” Fisher said.
“Immortal” Jellyfish Swarm World’s Oceans:
A potentially “immortal” jellyfish species that can age backward—the Benjamin Button of the deep—is silently invading the world’s oceans, swarm by swarm, a recent study says. Like the Brad Pitt movie character, the immortal jellyfish transforms from an adult back into a baby, but with an added bonus: Unlike Benjamin Button, the jellyfish can do it over and over again—though apparently only as an emergency measure.
About as wide as a human pinky nail when fully grown, the immortal jellyfish (scientific name: Turritopsis dohrnii) was discovered in the Mediterranean Sea in 1883. But its unique ability was not discovered until the 1990s. How the Jellyfish Becomes “Immortal”. Turritopsis typically reproduces the old-fashioned way, by the meeting of free-floating sperm and eggs. And most of the time they die the old-fashioned way too. But when starvation, physical damage, or other crises arise, “instead of sure death, [Turritopsis] transforms all of its existing cells into a younger state,” said study author Maria Pia Miglietta, a researcher at Pennsylvania State University. The jellyfish turns itself into a bloblike cyst, which then develops into a polyp colony, essentially the first stage in jellyfish life. The jellyfish’s cells are often completely transformed in the process. Muscle cells can become nerve cells or even sperm or eggs. Through asexual reproduction, the resulting polyp colony can spawn hundreds of genetically identical jellyfish—near perfect copies of the original adult. This unique approach to hardship may be helping Turritopsis swarms spread throughout the world’s oceans.