Meet your distant relative, Entelognathus primordialis, possibly the first earthling with a face. Or at least a familiar face.

Entelognathus primordialis (where Entelognathus means “complete jaw”) is described this week in Nature. Discovered in a quarry in China, the remarkably well-preserved fossil is somewhat 3D, displaying a modern type of jaw.

E. primordialis is a placoderm, an early class of fish that lived 430 to 360 million years ago. These fish were covered with an armor of bony plates and gave rise to two later groups—bony fish and cartilaginous fish.

The evolution of jaws is one of the key episodes in the evolution of vertebrates, but the gap between jawed and jawless vertebrates is so large that it has been hard to work out the individual evolutionary steps in the transition. Min Zhu and his colleagues hope to make the link with E. primordialis.

The 419 million-year-old fish fossil has jawbone features previously restricted to bony fishes, but has the full body armor seen in placoderms. It would have been around 20 centimeters (eight inches) long.

Prior to this recent find, most scientists agreed that placoderms had no jaw and were more similar to the cartilaginous fish, like modern day sharks, while the bony fishes are believed to be our ancestors. According to Nature News:

Such fishes went on to dominate the seas and ultimately gave rise to land vertebrates.

In addition to facing off with placoderms, the new study puts cartilaginous fishes into a whole new light—perhaps they are even more evolved than previously thought.

It’s sea otter awareness week, which seems like a great time to reveal something heroic about this charismatic animal. A recent study from UC Santa Cruz concluded that sea otters are helping to save the ocean—with their appetites.

When you think of sea otters, you may think “cute and cuddly,” but these playful marine mammals are top predators, like great white sharks and tigers, and their hunt for food is helping to maintain ecosystem health along portions of California’s coastline.

The sea otter’s role in ecosystem management begins with one of its preferred foods: crabs. Sea otters eat crabs. Crabs in turn eat sea slugs and small crustaceans. The slugs and crustaceans eat algae off sea plants, keeping them green and healthy. It’s a relatively typical food web but now it’s clear: The healthier the crab-eating otter population is, the healthier the plants tend to be.

Sea plants, like eelgrass, along the west coast are important habitat for fish such as Pacific herring, halibut and salmon. They also protect shorelines from storms and waves, and they soak up carbon dioxide from seawater and the atmosphere.  Thus, a healthy coastal ecosystem has the right mix of otters eating crabs and invertebrates eating algae.

Unfortunately, seagrass meadows have been declining worldwide, partly due to excessive nutrients from agricultural and urban runoff entering coastal waters.  When sewage and agricultural waste like fertilizers spill into the sea, ecosystems suffer. Excessive nitrogen and phosphorus in the water spawns excessive algae growth, which can block sunlight and limit plant growth. Coastal areas that would otherwise be swaying in seagrass and kelp turn brown, murky, and barren of important marine species. But, not when sea otters are around.

Brent Hughes from the University of California, Santa Cruz and his colleagues studied 50 years’ worth of data, comparing areas with or without otters. The team discovered that otters trigger the above ecological chain reaction that protects seagrass meadows and can stave off algal blooms.

“The seagrass is really green and thriving where there are lots of sea otters, even compared to seagrass in more pristine systems without excess nutrients,” Hughes says.

Sea otters were hunted to near extinction in the 19^th and 20^th centuries. Populations on the California coast are slowly recovering now, and one of those places otters have called home since the 1980s is Elkhorn Slough, an estuary in Monterey Bay. Hughes and his colleagues determined that the re-colonization of that estuary by sea otters has been an important factor in the seagrass comeback.

In Tomales Bay, a nearby inlet with far lower levels of incoming nutrients, but no otters, the beds don’t look nearly as good. Hughes told Ed Yong of National Geographic:

The seagrass looks relatively unhealthy: it’s brown, covered in algae, and slumped over. The crabs are four times more abundant and 30 percent bigger than they are in Elkhorn Slough.

The findings in Elkhorn Slough suggest that expansion of the sea otter population in California and re-colonization of other estuaries will likely be good for seagrass habitat—and coastal ecosystems—throughout the state.

“This provides us with another example of how the strong interactions exerted by sea otters on their invertebrate prey can have cascading effects, leading to unexpected but profound changes at the base of the food web,” Hughes says. “It’s also a great reminder that the apex predators that have largely disappeared from so many ecosystems may play vitally important functions.”

The study was published last month in the Proceedings of the National Academy of Sciences.

(Sea otters also play a heroic role in the next Academy planetarium show! Currently in production and set for a fall 2014 opening date, the latest production from our visualization studio will highlight complex relationships in ecosystems—and how humans fit into the picture.)

Jami Smith is a science geek-wannabe and volunteers for Science Today.

Image: Robert Scoles/NOAA

Roughly 70% water, Earth’s surface is covered with rivers, lakes, oceans, mud, and rain clouds. Scientists searching for alien life are searching for planets similar to our own, because experience tells us that life needs water in order to survive.

NASA’s Cassini spacecraft began photographing Titan, one of Saturn’s moons, in 2004. The pictures beamed back to Earth depict strange lakes and rivers. The European Space Agency (ESA)’s Huygens probe splashed into Titan’s mud in 2005, further convincing researchers that Titan was indeed “wet.”

The scientific community agrees that Titan appears Earth-like, but at temperatures around –290°F (–180°C), any water would be in the form of ice. Instead, astronomers believe any wetness on the surface of Titan is a combination of liquid methane, ethane, and other hard-to-freeze elements.

Apparently this moon doesn’t resemble Earth at all. Alex Hayes, a planetary scientist at Cornell University who works on the Cassini radar team, noticed something eerie while observing Saturn’s moon. “Where are all the waves?”

Wind, raindrops, and tides move Earth’s water in every direction. But Cassini has detected no wave action on Titan. It’s pretty strange, especially because, “[w]e know there is wind on Titan, the moon’s magnificent sand dunes prove it,” says Hayes.

Taking into account Titan’s gravity (one seventh that of Earth’s), the nature of fluids on its surface, and its dense atmosphere, Hayes and his colleagues calculated and published the speed needed for waves to form: only two miles per hour!

A strange puzzle, with even stranger solutions. Maybe the lakes are covered with tar, damping wave motion. Or they might be frozen. Or perhaps the wind hasn’t reached two miles per hour… yet.

Most of the lakes are located on Titan’s northern hemisphere, where it has been winter for a few years. The air during winter is colder and thicker, and may be the secret behind the missing waves.

If current climate models are correct, Cassini should be able to detect waves as Titan nears its summer solstice in 2017. Measurements and calculations of waves formed during the summer could tell us the chemical composition of Titan’s lakes… And reveal more about this Earth-like world so unlike Earth.

Alyssa Keimach is an astronomy and astrophysics student at the University of Michigan and interns for the Morrison Planetarium.

Image: NASA/JPL-Caltech/USGS

Academy scientist John McCosker describes a healthy, tropical shallow coral reef as an intricate network of shape, motion, and color. “The variety, amount, and numbers of coral, fish and invertebrates is impossible to describe,” he says. “It’s visually overwhelming.” In contrast, a reef damaged by dynamite, poison, or other methods of excessive resource extraction, appears as an ash-gray scar of calcium carbonate rubble along the ocean floor.

McCosker knows the difference first-hand. He made his first dive in the tropical Indo-Pacific with the Scripps Institution of Oceanography in 1972 in the vicinity of Raja Ampat. Recently, he accompanied Terry Gosliner, the Academy’s Dean of Science and Research Collections on a scouting expedition to Northwestern Papua in Indonesia. “There is no comparison between a healthy coral reef and one that’s been dynamited,” says McCosker. “That said, Raja Ampat remains one of the least inhabited and most pristine areas of the Coral Triangle.”

Many are working to keep it that way. The trip, explains Gosliner, is an initial step in what will be a five-year collaboration with the government of Indonesia, LIPI (the Indonesian Institute of Sciences), Conservation International, Papuan Indonesian scientists, educators and local fisherman. The Academy will work with Papuan residents to provide baseline documentation and training that will strengthen their effort to monitor and protect their newly formed marine sanctuaries.

Gosliner is working to complete a Memorandum of Understanding with the Government of Indonesia that will identify marine sites off of Birds Head peninsula where Academy scientists and their partners will document the biodiversity of those coral reefs.

Academy scientists will use the same methodology employed during the 2011 Hearst Philippines Biodiversity Expedition. Gosliner hopes the five-year effort will also settle an ongoing question among scientists—exactly where is the richest part of the ocean? “Some say it’s the Verde Island Passage in the Philippines,” Gosliner says, “others say it’s Raja Ampat. We hope to gather enough data to compare the two areas.

“Coral reefs are actually far more resilient than people realize,” says Gosliner. “We’ve seen transformation of once-decimated reefs into productive, recovering ecosystems. The key is to work with the local population to adopt sustainable practices. We will survey the biodiversity. But it’s just as important to build relationships with Indonesian scientists.”

The Academy, Gosliner explains, is not a newcomer to the issue of sustainability. “It’s been part and parcel of what we’ve done throughout our entire history. But we’re stepping up our efforts because the issue is so urgent and the challenges we face today are so great.”

Barbara Tannenbaum is a science writer working with the Academy’s Digital Engagement Studio. Her work has appeared in the New York Times, San Francisco Magazine and many other publications.

Image: Terry Gosliner

That’s marine biologist Rochelle Constantine of the University of Auckland. And while much of the unknown marine life may be small organisms such as sponges and small fish, Constantine is talking about a very rare whale.

The spade-toothed beaked whale (Mesoplodon traversii), was never seen before. The species was only known by three partial skulls collected from New Zealand and Chile over a 140-year period.

Then, two years ago, a stranded mother and her male calf died on a New Zealand beach. The New Zealand Department of Conservation photographed the animals and collected measurements and tissue samples.

The whales were initially identified as much more common Gray’s beaked whales. But then the scientists conducted routine DNA analysis. “When these specimens came to our lab, we extracted the DNA as we usually do for samples like these, and we were very surprised to find that they were spade-toothed beaked whales,” Constantine says. “We ran the samples a few times to make sure before we told everyone.”

Their findings were published earlier this month in Current Biology.

The discovery serves as a reminder of just how little we still know about life in the ocean, the authors say. They are still unsure why the whales are so elusive. “It may be that they are simply an offshore species that lives and dies in the deep ocean waters and only rarely wash ashore,” Constantine says.

Image: New Zealand Government

It all has to do with an experiment in the Indian Ocean in 2004. Scientists dumped seven tonnes of iron into an eddy in the Southern Ocean. As expected, an algal bloom followed. Scientific American describes this well:

A hunger for iron rules the microscopic sea life of the Southern Ocean surrounding ice-covered Antarctica. Cut off from most continental dirt and dust, the plankton, diatoms and other life that make up the broad bottom of the food chain there can’t get enough iron to grow.

The bloom was dominated by diatoms like the one pictured above. This group of algae are known to form large, slimy aggregates (marine snot) with high sinking rates at the end of their blooms. Indeed, after about a month, over 50% of the bloom sank deeply into the ocean, taking carbon dioxide with it as it went.

Science News quotes Victor Smetacek, lead author in the study, as saying:

“Every one atom of iron removed 13,000 atoms of carbon” from the air.

While scientists suspected this, they were never able to prove it. This is likely what happened during past ice ages. The air was cooler and drier then and carried more iron-containing dust from the continents to the ocean—lavishly supplying marine phytoplankton and removing carbon, cooling the atmosphere.

Now scientists are wondering if we can cool our warming climate by simply adding iron to the ocean. National Geographic has more on this geoengineering fix and other extreme geoengineering ideas to fight global warming. If only we spent this much energy on stopping global warming…

Image: Marina Montresor, SZN, Alfred Wegener Institute

Despite being in the wrong place, at the wrong time, we were able to catch incredible glimpses of the solar eclipse this week through photos throughout the web.

DNA sequencing started the year off right. Popular Science reported that “For the First Time, DNA Sequencing Technology Saves A Child’s Life.” Doctors, desperate to find the cause of a boy’s severe illness, sequenced his genes, discovered a mutation and were able to prescribe a treatment that appears to be working. A new machine could make this practice more common. An article in the New York Times this week described a more affordable sequencing machine. At $50,000, the Personal Genome Machine is significantly less than standard machines and “could expand the use of DNA sequencing from specialized centers to smaller university and industrial labs, and into hospitals and doctors’ offices.”

What is causing birds to fall out of the sky and fish to die from Arkansas to Maryland and Brazil to Sweden? Cold weather? Hail storms? Fireworks? The end of the world? There’s been much hype and speculation, but scientists don’t appear to be worried. The Academy’s own Jack Dumbacher is getting samples from the southern occurrences—he’s planning on testing the corpses for viruses. You can track these deaths yourself through Google maps or the US Geological Survey.

Finally, after topping the science news headlines last year, oil in the Gulf reappeared this week, at least on news sites. Have bacteria consumed nearly all of the methane from the spill? A study published in Science this week suggests that’s the case. Ed Yong finds a lot of support for the paper in his blog on Discover; Samantha Joye tells Science News, “Just because you can’t find methane in the spot where you lowered your [instruments] doesn’t mean there’s no methane out there somewhere.”

Also, the president’s oil spill commission released the first chapter of its report this week. (The entire report will be available next week.) An excerpt from the chapter in Science Insider reports that the blame for the disaster can be shared among the companies responsible for the well.

Most of the mistakes and oversights at Macondo can be traced back to a single overarching failure—a failure of management.

And sadly, this may not be an unusual event, according to the New York Times:

The commission warned that without major changes, another such accident was likely.

If you want a front seat on a Gulf of Mexico recovery expedition, follow Sylvia Earle and others on National Geographic News Watch this month.

What science news did you dive into this week? Share with us!

Image by Brydzo/Wikimedia

Earth

The Gulf oil spill—the number of gallons spilled and the controversy surrounding the damage seems to top many lists this year. Nature even named Jane Lubchenco, head of NOAA, its newsmaker of the year for how she handled the crisis.

Natural disasters often took the front page in 2010 with the Haitian earthquake and the eruption of Eyjafjallajökull topping many lists. The hard-to-pronounce Icelandic volcano also made many of the best science images of the year lists.

DiscoveryNews ends the year on a positive note with “How Humans Helped the Earth in 2010,” a slide show with text concerning recent strides in alternative energy, species and habitat conservation efforts and individual efforts to go green (electric cars, white roofs and saving energy).

For more environmental news of the year, New Scientist’s Short Sharp Science has a great review and the Nature Conservancy has a best/worst list on its site.

Life

Teeny, modified life stole the spotlight this year—the J. Craig Venter Institute’s so-called “synthetic cell” and GFAJ-1—the bacteria that incorporates arsenic into its DNA—or so NASA scientists claimed.  Science writer Carl Zimmer discredited the arsenic bacteria paper on Slate; NASA author Felisa Wolfe-Simon defended herself in Science. Fun stuff!

The spread of pesky bedbugs was number six in Discover’s “Top 100 Science Stories of 2010.”

Nature’s great article this past summer on eradicating mosquitoes was among its readers’ top choices of the year.

Looking for something a little bigger and less controversial? New Scientist has “The coolest animals of 2010,” which includes a scorpion-eating bat and a fly thought to be extinct for over 160 years!

NPR found it was a very good year for Neanderthals—their genome was sequenced, brain examined and diet expanded.

Remarkably, the Census of Marine Life tops the BP oil spill in the Deep Type Flow blog’s biggest marine science stories of the year for its sheer numbers:

…over 500 research expeditions covering every ocean, over 2,500 scientists and the discovery of over 6,000 species new to science and published in over 2600 peer-reviewed papers.

Space

ScienceNow’s most popular story of all time, not just 2010, was “Does Our Universe Live Inside a Wormhole?” A wonderful theory that we also covered last spring.

Exoplanets, in part thanks to the Kepler mission, were all over the news this year—whether it had to do with size, atmosphere or number within a star system. Discover’s interview with local exoplanet hunter (and California Academy of Sciences Fellow) Geoff Marcy made number 11(!) on their 100 top stories list.

A little closer to home, Jupiter’s missing stripe and Neptune’s tale of cannibalism are included in New Scientist’s most popular space stories of 2010.

Our Moon and Saturn’s moons made news throughout the year and the top lists on Universe Today and Wired this week.

Universe Today also included SDO’s new views of the sun in their top stories list. Stunning!

Hubble celebrated its 20^th year in space this year by taking even more beautiful images. Several are included in Bad Astronomy’s “Top 14 Astronomy Pictures of 2010.”

Technology

Electric cars and NASA’s new foray into commercial spacecraft are included in Scientific American’s top ten stories of the year.

The Large Hadron Collider was very busy this year, and topped many lists. Another machine at CERN made news (and also topped Nature’s readers’ choice list) when it was able to capture antimatter for a sixth of a second!

Graphene not only garnered a Nobel Prize this year, the material (and it’s potential) also made news and top science lists of the year.

DiscoveryNews put plastics on their 2010 list—whether its finding new ways of removing plastic from the oceans or engineering smarter plastics.

What was your favorite science story of the year? Share with us by adding it to the comment section below!

Image by Les Stone, International Bird Rescue Research Center/Wikipedia

Salps are a type of tunicate or sea squirt, small gelatinous creatures that live in the oceans and are chordates, which makes them more closely related to us than they are to the jellyfish they resemble. They can exist either singly or in chains that may contain a hundred or more of the five-inch animals (National Geographic has a great video on YouTube of a long salp chain).

Salps are known to be efficient eaters and in fact, as this older article in Discover points out,

Moving and eating are the same thing for them. As water flows into one open end of the barrel, the barrel contracts, shooting the water out the back and pushing the salp forward. On its way, though, the water passes through an internal net of mucus, sort of like a sleeve lining, that strains out particles as small as bacteria.

(These creatures are so efficient, the article continues, numerous parasites love salps.)

Recent research published this week in the journal Proceedings of the National Academy of Sciences (PNAS), illuminates how impressive and important these little ocean vacuums are.

According to LiveScience,

…The new results show these animals can consume particles that span a huge size range, or about four orders of magnitude, from a fraction of a micrometer to a few millimeters. If sized up that range would be like eating everything from a mouse to a horse, [co-author Larry] Madin said.

And in fact, they prefer the smaller particles. Again from LiveScience:

In the laboratory at WHOI, [lead author Kelly] Sutherland and her colleagues offered salps food particles of three sizes: smaller, around the same size as, and larger than the mesh openings.

“We found that more small particles were captured than expected,” said Sutherland, now a post-doctoral researcher at Caltech. “When exposed to ocean-like particle concentrations, 80 percent of the particles that were captured were the smallest particles offered in the experiment.”

According to Madin, “Their ability to filter the smallest particles may allow them to survive where other grazers can’t.”

Perhaps most significantly, the result enhances the importance of the salps’ role in carbon cycling. As they eat small and large particles, “they consume the entire ‘microbial loop’ and pack it into large, dense fecal pellets,” Madin says.

The larger and denser the carbon-containing pellets, the sooner they sink to the ocean bottom. “This removes carbon from the surface waters,” says Sutherland, “and brings it to a depth where you won’t see it again for years to centuries.”

But wait, there’s more. Co-author Roman Stocker of MIT says that the more carbon that sinks to the bottom, the more space there is for the upper ocean to accumulate carbon, hence limiting the amount that rises into the atmosphere as CO₂.

Thanks, salps!

Image Kelly Sutherland and Larry Madin, WHOI