Archive for the ‘marine biology’ Category

ENCOUNTERING a mighty sperm whale is a magical experience. But in this case, it was tempered somewhat by a rarely seen defence mechanism: emergency defecation.

Sperm whales are the largest toothed predators in the world, so what have they got to be scared of? Here it was pesky divers buzzing around them, taking photos.

Canadian photographer Keri Wilk was sailing off the island of Dominica in the Caribbean, hoping to film these gargantuan creatures, when he spotted one and jumped in for some close-ups. The whale approached Wilk and his three colleagues, pointed downwards, and began to evacuate its bowels. To make matters worse, it then started to churn up the water. “Like a bus-sized blender, it very quickly and effectively dispersed its faecal matter into a cloud,” says Wilk.

Defensive defecation has been recorded in pygmy and dwarf sperm whales, which, as their names suggest, are diminutive compared with their cousins. But this is perhaps less surprising, given that they have natural predators. Wilk is unaware of any other reports of sperm whales’ emergency excretion.

Despite what you might think of being enveloped in what Wilk describes as a “poonado”, he cherishes the moment. “I’ve experienced lots of interesting natural phenomenon underwater, all over the world, but this is near the top of the list,” he says. “As long as you didn’t take your mask off, you couldn’t really smell anything. Taste is another matter…”

http://www.newscientist.com/article/mg22530064.700-sperm-whales-emergency-evacuation-of-its-bowels.html#.VMtpm4dRGng

A pod of “false killer whales” made an unexpected visit to the Orange County coast Wednesday, delighting school children on whale-watching tours as the mammals romped through the waves and circled a boat.

The rarely seen whales, last reported off Orange County in 2005, were spotted by the crew of the Sea Explorer from the Ocean Institute in Dana Point late Wednesday morning off San Clemente. About 70 children from Brywood Elementary School in Irvine saw the whales in two separate trips on the vessel, 35 children each, and the whales put on a show.

“At one point when they stopped, they encircled the boat, some of them coming up against it and rubbing on the hull,” said the Sea Explorer’s captain, marine biologist Mike Bursk. “And of course the kids were going crazy.”

One of the whales also took a deep dive and returned with a large white sea bass clamped in its jaws, Bursk said.

The large, boisterous members of the dolphin family, usually found much farther out to sea, drew other vessels, including a boat from Capt. Dave’s Dolphin and Whale Watching Safari.

Capt. Dave himself – Dave Anderson – got close-ups of a curious false killer whale when he went out alone in an inflatable boat and thrust a GoPro camera into the water.

“All of a sudden, one just came right over, and he was right next to my hand,” Anderson said. “I was getting a little bit nervous, because these guys are carnivores.”

The creatures seemed to investigate everything about the boat, including the motor, he said.

“If you look at the video, you can see how long that animal stayed there, turning upside-down and checking out the camera,” he said.

A group of children from San Juan Elementary School aboard the Dana Pride from Dana Wharf Sportfishing and Whale Watching, also got a good view of the whales, passing up a gray whale in order to see them, said Todd Mansur, the boat’s captain.

http://www.ocregister.com/articles/whales-605430-boat-whale.html

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By Alan Yu

Sharks in Western Australia are now tweeting out where they are.

Government researchers have tagged 338 sharks with acoustic transmitters that monitor where the animals are. When a tagged shark is about half a mile away from a beach, it triggers a computer alert, which tweets out a message on the Surf Life Saving Western Australia Twitter feed. The tweet notes the shark’s size, breed and approximate location.

Since 2011, Australia has had more fatal shark attacks than any other country; there have been six over the past two years — the most recent in November.

The tagging system alerts beachgoers far quicker than traditional warnings, says Chris Peck, operations manager of Surf Life Saving Western Australia. “Now it’s instant information,” he tells Sky News, “and really people don’t have an excuse to say we’re not getting the information. It’s about whether you are searching for it and finding it.”

The tags will also be monitored by scientists studying the sharks. Researchers have tagged great whites, whaler sharks and tiger sharks.

“This kind of innovative thinking is exactly what we need more of when it comes to finding solutions to human-wildlife conflict,” says Alison Kock, research manager of the Shark Spotters program in South Africa. Kock tells NPR that the project is a good idea — but that people should know that not all sharks are tagged.

Her program does the same work, but humans do the spotting and tweeting.

Kock and Kim Holland, a marine biologist who leads shark research at the University of Hawaii, agree that the tweets won’t be enough to protect swimmers.

“It can, in fact, provide a false sense of security — that is, if there is no tweet, then there is no danger — and that simply is not a reasonable interpretation,” Holland says, pointing out that the reverse is also true. “Just because there’s a shark nearby doesn’t mean to say that there’s any danger. In Hawaii, tiger sharks are all around our coastlines all the time, and yet we have very, very few attacks.”

In Western Australia, the local government recently proposed a plan to bait and kill sharks that swim near beaches.

Holland says most shark biologists would agree that’s not a good plan, partly because of what researchers have learned using acoustic transmitters. Scientists tracking white sharks, for example, found that the species can travel great distances, going from Western Australia to South Africa in some cases.

“Because we know that they are so mobile, we’re not sure that killing any of them will have any effect on safety,” Holland says, pointing out that great white sharks don’t set up shop along the same coastlines for long. He says the number of these sharks is on the rise — but there aren’t that many to begin with.

“The other side of the coin is that it’s a horrible thing to see when people get killed, so there’s often public outcry for government agencies to do something.”

http://www.npr.org/blogs/alltechconsidered/2013/12/31/258670211/more-than-300-sharks-in-australia-are-now-on-twitter?ft=1&f=1001

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About 54 million years ago, a semiaquatic deerlike creature headed into the water for good, giving rise to whales and their relatives. The newly sequenced genome of the minke whale, a baleen whale found worldwide, tells the story of how stressful this move to live underwater was. An international team has decoded the genomes of four minke whales, a fin whale, a bottlenose dolphin, and a finless porpoise, comparing these cetaceans’ genes to the equivalent genes in other mammals. It found whale-specific mutations in genes important for the regulation of salt and of blood pressure and for antioxidants that get rid of charged oxygen molecules that can harm cells. These molecules increase in number as the whale uses up its oxygen supply during dives. Whales also had larger numbers of related genes, called gene families, for dealing with sustained dives, the team reports online today in Nature Genetics. Overall, 1156 gene families had expanded, and several increased the number of enzymes that help the whale cope with low-to-no oxygen conditions. A few of those expanded families are also expanded in naked mole rats, which live underground where oxygen is scarce. But the numbers of genes for body hair and for taste and smell had decreased. And of course, there were genes and gene families that help explain why whales look the way they do.

http://news.sciencemag.org/biology/2013/11/scienceshot-how-whale-became-whale

Thanks to Dr. Rajadhyaksha for bringing this to the attention of the It’s Interesting community.

<> on June 9, 2010 in Houma, Louisiana.

By Susannah Cullinane, CNN

The world’s oceans have become 26% more acidic since the start of the Industrial Revolution and continue to acidify at an “unprecedented rate,” threatening marine ecosystems, aquaculture and the societies that rely on them, scientists say.

In a report released Thursday, researchers say that carbon dioxide emissions from human activities such as fossil fuel burning are the primary cause of ocean acidification.

They say the rate of change may be faster than at any time in the last 300 million years, predicting that by 2100 there will have been a 170% increase in ocean acidity, compared to pre-industrial times.

The report is based on the findings from a September 2012 Symposium on the Ocean, at which 540 experts from 37 countries discussed research on ocean acidification, and has been updated with more recent research.

Unless carbon dioxide emissions are reduced, marine ecosystems will be damaged and the impact of climate change will be worsened, the scientists warn. “The only known realistic mitigation option on a global scale is to limit future atmospheric CO2 levels.”

The report says oceans currently act as a CO2 “sinkhole” absorbing approximately a quarter of emissions.

“As ocean acidity increases, its capacity to absorb CO2 from the atmosphere decreases. This decreases the ocean’s role in moderating climate change,” they write.

The increased acidity will also change the ocean environment, with evidence suggesting that some organisms will be less able to survive, while others, such as seagrass, may thrive.

Acidification is faster in Arctic waters because cold water is richer in CO2, while melting sea ice worsens the problem, they say.

“Within decades, large parts of the polar oceans will become corrosive to the unprotected shells of calcareous marine organisms,” the report says, while in the tropics the growth of coral reefs may be hampered.

“People who rely on the ocean’s ecosystem services are especially vulnerable and may need to adapt or cope with ocean acidification impacts within decades,” it says. “Tropical coral reef loss will affect tourism, food security and shoreline protection for many of the world’s poorest people.”

“Very aggressive reductions in CO2 emissions are required to maintain a majority of tropical coral reefs in waters favorable for growth,” the report says.

One of the report’s authors is Daniela Schmidt, from the University of Bristol, in the UK.

Schmidt said the research highlighted the impact acidification would have on biodiversity and aquaculture and the societies that rely on them for their food and economic well-being.

“We’re talking about countries that strongly depend on this, in warmer countries where there are complex problems with climate change as it is,” Schmidt said.

“What I’m hoping is that people realize that CO2 is not just a question of global warming. That we are acidifying the ocean at a rate that has been unprecedented — for millions and millions of years,” she said.

“The more CO2 emissions, the more acidification,” Schmidt said. “The ocean is in direct interchange with the atmosphere.”

If acidification continued to increase at its current rate, “you will definitely see damage,” she said. “The first signs we can already see today, in oyster farms off the West Coast of the United States.”

Schmidt said while 90% of the world’s ocean was in equilibrium with the atmosphere, some oyster hatcheries in this area were located in the 10% that wasn’t.

Oysters in the larval stage were much more vulnerable to damage, she said. “When (more acidic) water comes up and hits the hatchery, they close the whole thing.”

While tanks could be closed off to more acidic seawater, Schmidt said that by 2100 the issue would be there every day. “So we can’t just switch off that tap anymore.”

She said the report would be presented in Warsaw, Poland, on November 18, during the U.N. Conference of the Parties climate change meeting.

Schmidt said while she hoped the research would lead to stricter emissions limits, “the realist in me thinks that we’ve been discussing this for decades. This isn’t a problem that is just going to go away. It’s simple. The consequences are frightening.”

The 2012 symposium that led to the report was sponsored by the Scientific Committee on Oceanic Research, the Intergovernmental Oceanographic Commission of UNESCO, and the International Geosphere-Biosphere Programme.

http://www.cnn.com/2013/11/14/world/ocean-acidification-report/index.html?hpt=hp_t3

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The search continues for life in subglacial Lake Whillans, 2,600 feet below the surface of the West Antarctic Ice Sheet—but a thrilling preliminary result has detected signs of life.

At 6:20am on January 28, four people in sterile white Tyvek suits tended to a wench winding cable onto the drill platform. One person knocked frost off the cable as it emerged from the ice borehole a few feet below. The object of their attention finally rose into sight: a gray plastic vessel, as long as a baseball bat, filled with water from Lake Whillans, half a mile below.

The bottle was hurried into a 40-foot cargo container outfitted as a laboratory on skis. Some of the lake water was squirted into bottles of media in order to grow whatever microbes might inhabit the lake. Those cultures could require weeks to produce results. But one test has already produced an interesting preliminary finding. When lake water was viewed under a microscope, cells were seen: their tiny bodies glowed green in response to DNA-sensitive dye. It was the first evidence of life in an Antarctic subglacial lake.

(A Russian team has reported that two types of bacteria were found in water from subglacial Lake Vostok, but DNA sequences matched those of bacteria that are known to live inside kerosene—causing the scientists to conclude that those bacteria came from kerosene drilling fluid used to bore the hole, and not from Lake Vostok itself.)

In order to conclusively demonstrate that Lake Whillans harbors life, the researchers will need to complete more time-consuming experiments showing that the cells actually grow—since dead cells can sometimes show up under a microscope with DNA-sensitive staining. And weeks or months will pass before it is known whether these cells represent known types of microbes, or something never seen before. But a couple of things seem likely. Most of those microbes probably subsist by chewing on rocks. And despite being sealed beneath 2,600 feet of ice, they probably have a steady supply of oxygen.

The oxygen comes from water melting off the base of the ice sheet—maybe a few penny thicknesses of ice per year. “When you melt ice, you’re liberating the air bubbles [trapped in that ice],” says Mark Skidmore, a geomicrobiologist at Montana State University who is part of the Whillans drilling, or WISSARD, project. “That’s 20 percent oxygen,” he says. “It’s being supplied to the bed of the glacier.”

In one possible scenario, lake bacteria could live on commonly occurring pyrite minerals that contain iron and sulfur. The bacteria would obtain energy by using oxygen to essentially “burn” that iron and sulfur (analogous to the way that animals use oxygen to slowly burn sugars and fats). Small amounts of sulfuric acid would seep out as a byproduct; that acid would attack other minerals in the sands and sediments of the lake—leaching out sodium, potassium, calcium, and other materials that would accumulate in the water.

This process, called weathering, breaks down billions of tons of minerals across the Earth’s surface each year. Researchers working on the National Science Foundation-funded WISSARD project hope to learn whether something like this also happens under the massive ice sheets covering Antarctica and Greenland. They’ve already seen one tantalizing sign.

The half mile of glacial ice sitting atop Lake Whillans is quite pure—derived from snow that fell onto Antarctica thousands of years ago. It contains only one-hundredth the level of dissolved minerals that are seen in a clear mountain creek, or in tap water from a typical city. But a sensor lowered down the borehole this week showed that dissolved minerals were far more abundant in the lake itself. “The fact that we see high concentrations is suggestive that there’s some interesting water-rock-microbe interaction that’s going on,” says Andrew Mitchell, a microbial geochemist from Aberystwyth University in the UK who is working this month at Lake Whillans.

Microbes, in other words, might well be munching on minerals under the ice sheet. The Whillans team will take months or years to unravel this picture. They will perform experiments to see whether microbes taken from the lake metabolize iron, sulfur, or other components of minerals. And they will analyze the DNA of those microbes to see whether they’re related to rock-chewing bacteria that are already known to science.

Antarctica isn’t the only place in the solar system where water sits concealed in the dark beneath thick ice. Europa and Enceladus (moons of Jupiter and Saturn, respectively) are also thought to harbor oceans of liquid water. What is learned at Lake Whillans could shed light on how best to look for life in these other places.

http://blogs.discovermagazine.com/crux/2013/01/29/first-evidence-of-life-in-antarctic-subglacial-lake/

Thanks to Kebmodee for bringing this to the attention of the It’s Interesting community.

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In a proposal almost as fanciful as the fictional 20,000 Leagues Under the Sea by Jules Verne, the Defense Advanced Research Projects Agency kicked off a research project last Friday to develop sensor systems that could be placed miles below the surface of the ocean and activated when needed by a remote command.

DARPA said it wants to develop a system that can store unmanned sensors such as waterborne or airborne cameras, decoys, network nodes, beacons and jammers, in watertight capsules that can withstand pressure at depths up to six kilometers (3.7 miles) and then be launched to the surface “after years of dormancy.”

Nearly half of the world’s oceans have depths deeper than 4 kilometers (2.5 miles), DARPA said, “which provides a “vast area for concealment of storage” and this concealment “also provides opportunity to surprise maritime targets from below, while its vastness provides opportunity to simultaneously operate across great distance,” DARPA said.

The agency said it envisions the subsystems of its Upward Falling Payloads projects will consist of a sensor payload, a “riser” providing pressure tolerant encapsulation of the payload and a communication system triggering launch of the payload stored on a container with an inner, 4-7/8 inch diameter and a length of 36 inches.

In the first stage of the three-phase project expected to cost no more than $1.75 million, DARPA wants researchers to concentrate on a communications system that avoids “false triggers” of the deep-sea systems and can operate at long distances from the submerged sensors. Proposals for this phase also should detail the design of a capsule and riser system that will work after sitting for years on the seabed, and potential sensor systems for military or humanitarian use.

The second phase of the project calls for the communication system to “wake up” the system on the seabed and launch it, with tests planned the Western Pacific in 2015 and 2016,though tests also could be conducted in the Atlantic or offshore from Hawaii, DARPA said.

In the third phase, planned for 2017, DARPA plans tests of a completely integrated and distributed Upward Falling Payloads system at full depth in the Western Pacific.

Proposals are due March 12 and DARPA expects to make an award in June.

http://www.nextgov.com/defense/2013/01/darpa-eyes-pop-deep-sea-sensors/60655/

Thanks to Kebmodee for bringing this to the attention of the It’s Interesting community.