The fossilised skull of a gigantic predator has been found off the English Channel coast of southern England.

The skull is 2.4 meters long and scientists believe it once belonged to a 16 meter long pliosaur which probably weighed an impressive 12 tons.

The pliosaurs were a type of ocean dwelling reptiles that dominated the seas roughly 150 million years ago.

The man behind the discovery is fossil hunter Kevin Sheehan from Dorset who gradually uncovered the remains of the fragmented skull over a number of years.

“In 40 years of collecting, I have often been green with envy at some of the finds other people have made“, said Sheehan. “But now when someone shows me a find, I can say ‘That’s not a fossil, this pliosaur, that’s a fossil’.”

The fossilised skull is 90% complete and clearly shows the jaws of a powerful predator.

“These creatures were monsters”, says Dr David Martill, a palaeontologist from the University of Portsmouth. “They had massive big muscles on their necks, and you would have imagined that they would bite into the animal and get a good grip, and then with these massive neck muscles they probably would have thrashed the animals around and torn chunks off. It would have been a bit of a blood bath.”

Martill suspects that the skull may belong to a species of pliosaur that haven’t been unearthed until now.

“This is one of the largest, if not the largest, pliosaur skull found anywhere in the world and contains features that have not been seen before“, he explains. “It could be a species new to science.”

The skull has been purchased by the Dorset County Council and will be displayed in the county museum.

According to geologist James W. Castle and ecotoxicologist John H. Rodgers, both of the Clemson University in South Carolina, toxin-producing algae caused or contributed to the mass extinction of dinosaurs.

After spending two years analyzing data from ancient algal deposits, so called stromatolite structures, the researchers have found evidence that blue-green algae where present in sufficient quantities to kill off countless numbers of plants and animals living in the ocean or on land at the time. Blue-green algae may not seem very harmful, but they produce toxins and deplete oxygen.

Other researchers have suggested that phenomena such as volcanic activity, climate change, sea level changes or asteroids are responsible for the five major extinctions and a number of other significant die-offs during the part of Earths history during which life with skeletons or shells have existed. According to Castle and Rodgers, all these phenomena contributed to the mass deaths but algae was the most important factor.

“The fossil record indicates that mass extinctions… occurred in response to environmental changes at the end of the Cretaceous; however, these extinctions occurred more gradually than expected if caused solely by a catastrophic event,” Castle and Roger argue in their work.

The part of the study that has caused the most debate so far is the warning that current global warming may cause similar die-offs, since our current environmental conditions show significant similarity to times when mass die-offs have occurred.

“This hypothesis gives us cause for concern and underscores the importance of careful and strategic monitoring as we move into an era of global climate change,” Castle and Roger writes, adding that the level of “modern toxin-producing algae is presently increasing, and their geographic distribution is expanding… “

The paper has already gained a lot of attention within the scientific community.

“Scientists from around the world have been sending us data that support our hypothesis and our concern about the future,” says Rodgers. “I look forward to the debate this work will generate. I hope it helps focus attention on climate change and the consequences we may face.”

You can download the entire “Hypothesis for the role of toxin-producing algae in Phanerozoic mass extinctions based on evidence from the geologic record and modern environments” from Clemson University.

http://www.clemson.edu/media-relations/files/articles/2009/2336_295_mass_extinctions.pdf

The work has also been published in the March 2009 issue of the journal Environmental Geosciences.

In order to survive until it becomes a skilled hunter, a shark pups is born with an enlarged “super liver” that functions as a food source for several months.

This new finding have surprised marine scientists, because shark pups were believed to suffer from a high mortality rate because they had to find food immediately after being born.

“They’re much more likely to survive when they’re born than we previously thought,” says Australian Institute of Marine Science researcher Aaron MacNeil.

Unlike live-bearing sea mammals like dolphins and whales, live-bearing shark mothers do not produce milk for their offspring. Until know, researchers assumed that the shark mothers didn’t invest much energy into keeping the offspring alive once it was born, but the new finding changes this perception radically. The shark mother is effectively sending her young off with a liver so packed with energy and nutrients that it keeps the baby fed for several months.

“It is likely that the liver reserves enable the newborn sharks to acclimatize themselves to their environment and to develop their foraging skills,” says lead researcher Nigel Hussey, “We know that large sharks use their livers as an energy store, but we had no idea that the mother provisions her young with additional liver reserves to enhance their survival.”

The research that led to the discovery was carried out by an international team of researchers headed by the Bangor University in Wales.

Researchers from Emory University have identified the first fish to have switched from ultraviolet vision to violet vision, i.e. the ability to see blue light. This fish in question – a type of scabbardfish – is also the first example of an animal where a deleted molecule has resulted in a change in visual spectrum.

Many species, including humans, have violet vision but our common vertebrate ancestor had UV-vision and could not sense the blue colour spectrum.

All fish studied before the scabbardfish have been found to have UV vision. The scabbardfish is believed to have switched from UV vision to violet vision by deleting the molecule at site 86 in the chain of amino acids that makes up the opsin protein.

“Normally, amino acid changes cause small structure changes, but in this case, a critical amino acid was deleted,” Yokoyama explains.

Vision is of particular interest to evolutionary geneticists since it is a comparatively straight-forward sensory system with a low number of genes involved. Human vision is for instance made possible by no more than four genes.

“It’s amazing, but you can mix together this small number of genes and detect a whole color spectrum,” says evolutionary geneticist and research team leader Shozo Yokoyama. “It’s just like a painting.”

In their study, the Emory researchers linked molecular evolution to functional changes and the possible environmental factors driving them.

“This multi-dimensional approach strengthens the case for the importance of adaptive evolution,” says Yokoyama. “Building on this framework will take studies of natural selection to the next level.”

The Scabbardfish spends most of its life at a depth of 25-100 meters and at these depths UV light is less intense then violet light, something which may have prompted the change in vision. Living deep down in the ocean will however not necessarily make you benefit from a vision switch; the Lampfish has for instance retained its UV vision – most likely because it swims up to the surface at night to feed on translucent crustaceans that are easier to locate if you have UV vision.

“The finding implies that we can find more examples of a similar switch to violet vision in different fish lineages,” says Yokoyama. “Comparing violet and UV pigments in fish living in different habitats will open an unprecedented opportunity to clarify the molecular basis of phenotypic adaptations, along with the genetics of UV and violet vision.”

The article has been published in the October 13 issue of Proceedings of the National Academy of Sciences.

http://www.pnas.org

In addition to evolutionary geneticist Shozo Yokoyama, the research team also included post-doctoral fellow in biology Takashi Tada and post-doctoral fellow in biology and computational chemistry Ahmet Altun.

Barnacles are capable of attaching themselves to virtually any underwater surface; from whale skin and turtle shells to ship hulls and pier structures. Just how they manage to keep themselves anchored has remained a mystery; a multimillion mystery since barnacles increase fuel consumption by adding additional drag to the submerged parts of marine vessels. Scientists knew that the barnacles used a type of glue, but they didn’t understand how it worked and why it was so strong.

Traditionally, toxic paint has been used to keep the barnacles away but dry-docking huge cargo ships every so often to have them repainted is naturally expensive. Also, the toxic paint is not only affecting the barnacles; it is causing problems for entire ecosystems and many countries have therefore decided to ban or limit the use of some of the most harmful ones.

Using modern techniques such as force microscopy and mass spectrometry, a team of scientists from Duke University’s Marine Laboratory in Durham has now managed to find out how barnacles stick to surfaces; a discovery which they hope will lead to the development of more environmentally friendly anti-barnacle remedies.

The research team unveiled that barnacle glue from the species Amphibalanus amphitrite binds together much the same way as red blood cells bind together when our blood clots. When our blood clot, several different enzymes work together to form protein fibres that bind the cells together. In barnacle glue, similar enzymes – known as trypsin-like serine proteases – do the same thing. Interestingly enough, one of these enzymes are remarkably similar to Factor XIII, and essential blood clotting agent present in human blood.

“We’ve found homologous enzymes in barnacles and humans, which serve the same function of clotting proteins underwater, despite roughly a billion years of evolutionary separation,” says research team member Dr Gary Dickinson.

Another team member, Professor Dan Rittschof, explains that this similarity does make evolutionary sense.

“Virtually no biochemical pathway is brand new. Everything is related and really important pathways are used over and over,” says Rittschof. “Really key parts of those pathways can’t change because if they do, the pathway fails and the animal dies.”

According to Dickinson, it wouldn’t be surprising to find this glue in other organisms besides the barnacles.

“The enzymes are highly conserved because they are very effective at what they do, ” says Dickinson. “There are bound to be a number of other organisms that use the same enzymes for the same purpose.”

For more information, read the article in The Journal of Experimental Biology.

http://jeb.biologists.org

A 10-year study of Rockefeller Wildlife Refuge alligators has yielded some surprising results. Despite having plenty of suitable males to choose among, up to 70 percent of the female gators in this Louisiana refuge preferred to mate with the same male year after another. Also, females who mated with more than one male per breeding season and produced young from multiple fathers usually continued to mate with their select group of males year after year, thus displaying a form of polygamous fidelity.

“Given how incredibly open and dense the alligator population is at RWR, we didn’t expect to find fidelity,” biologist Stacey Lance of the Savannah River Ecology Laboratory in South Carolina said in a press release. “To actually find that 70 percent of our re-trapped females showed mate fidelity was really incredible. I don’t think any of us expected that the same pair of alligators that bred together in 1997 would still be breeding together in 2005 and may still be producing nests together to this day.”

Most reptiles are polygamous and will choose a new mate or mates each breeding season, and only a few reptilian species are known to actively choose the same mate or mates over and over again.

Since the Rockefeller Wildlife Refuge is so densely populated with alligators, researchers don’t think that the repeated pairings are the result of chance.

The study has been published in the journal Molecular Ecology.

http://www3.interscience.wiley.com/journal/117989598/home

In the ocean, krill live together in swarms, some of them stretching for tens of kilometres. Krill swarms are some of the largest gatherings of life on the planet and this naturally poses some puzzling questions to science: Why are krill living together? How do they find each other? Why are some swarms enormous when others are more moderately sized?

In an effort to shed some light on the mystery, a team of British Antarctic Survey (BAS) researchers headed by Dr Geraint Tarling set out to study the composition and structure of 4525 separate krill swarms in the Scotia Sea. Despite its name, the Scotia Sea is not located close to home for these British scientists – it is a vast expanse of water situated partly in the Southern Ocean and partly in the Atlantic; between Argentina and the Antarctic Peninsula.

Using echo-sounding equipment, the Tarling team tracked down the krill living in this 900,000 km² area and what they found surprised them. According to this new research, krill normally gather into two different types of swarms. The first type is relatively small, typically not exceeding a length of 50 meters and a depth of 4 meters. In this comparatively small type of swarm, the density of krill isn’t very high – you will just find an average of ten krill per cubic meter.

The other type of swarm – dubbed “superswarm” by the researchers – is on the other hand a very densely packed group with up to 100 krill per cubic meter. These dense congregations are the ones that grow really big, often stretching over one kilometre in length and averaging almost 30 meter in depth.

“I was coming at it thinking there might be small swarms tightly packed, and then large swarms that were a bit more diffuse,” says Dr Tarling. “But what we actually found was the opposite. There were small swarms that were quite diffuse and large swarms that were tightly packed.”

This means that a majority of the krill living in the Scotia Sea at any one time will be found within one of just a few enormous superswarms.

“We talking trillions of krill in one aggregation,” explains Dr Tarling. “Ten or 12 swarms could explain 60 or 70% of the biomass in an area the size of the eastern Atlantic. It was astonishing how much biomass could be concentrated into such a small area.”

A fishing flee scooping up a whole swarm of krill may therefore be removing the majority of krill from the Southern Ocean in just one short fishing trip if they happen to target one of the superswarms instead of a small swarm.

How does a superswarm come about?

Although they weren’t able to fully answer this question, Tarling and his colleagues managed to pinpoint certain factors that make superswarms more likely to appear.

“The factors we identified included whether there was more likely to be a lot of food around or not, and when there wasn’t that much food around, they tended to form larger swarms,” says Dr Tarling.

Age is also of importance. The smaller, diffuse swarms typically contained adult krill, while the enormous superswarms consisted of densely packed juvenile individuals.

“Where the animals were less mature, they were more likely to form the larger swarms,” says Dr Tarling, adding that he doesn’t know why.

It might be a question of safety in numbers; it is common among prey animals to live in large groups to reduce the risk of getting eaten, and krill is after all a favoured meal by a long row of sea living creatures.

“All types of swarms are probably to a greater or lesser extent an antipredator response,” Dr Tarling says.

But although living in a swarm reduces the risk of being eaten, it also means having to compete with all the other members of the group for food. Juvenile krill are more buoyant than adults, which mean that they spend less energy swimming. Perhaps this is why adult krill prefers to live in smaller congregations; their negative buoyancy forces them to eat more so they can’t afford living in a huge swarm densely surrounded by competitors.

On the other hand, being in a swarm has been shown to be more energetically efficient than being isolated.

“For a juvenile that wants to grow very quickly, saving energy could be a bonus for them,” says Dr Tarling.

Night-time mystery

As a scientist, you often find yourself in a situation where new findings answer one question but simultaneously create three new ones. One of the new conundrums that Dr Tarling has brought back home from his research trip is the following: Why are superswarms more likely to form at night?

“That is more puzzling for us to explain,” says Dr Tarling. “Up until this point, most polar biologists believed that the swarms dispersed [at night], because that’s the time they feed. When daylight comes they get back into the swarm again for the antipredator benefit. But we found the opposite to that.”

The research has been published in the journal Deep Sea Research I.

Researchers at Woods Hole Oceanographic Institution (WHOI) and the University of South Carolina has managed to solve a conundrum that’s been puzzling marine scientists for roughly a decade – where does all the oceanic phosphonate come from?

Roughly a decade ago, phosphonate – a rare form of organic phosphorus – was discovered in marine organic matter. Not only were researchers baffled to find this rare form of phosphorus in the ocean; they were also flummoxed by the high concentrations in which it was found throughout the sea. No one could explain where it came from and why it could be found in such abundance.

That is, no one could explain it until now.

In 2006, biologist Sonya Dyhrman and her WHOI team commenced a field and laboratory study on a group of phytoplankton called Trichodesmium. Trichodesmium is a microscopic marine microbe found in ample amounts throughout warm tropical and subtropical waters where nutrients are scarce. The WHOI team were able to show that Trichodesmium uses phosphonate to support carbon and nitrogen fixation, and that a special set of genes have given them this capacity. This triggered Dyhrman’s curiosity – where did Trichodesmium get its phosphonate from in the first place?

To solve the mystery, Dyhrman partnered up with Claudia Benitez-Nelson, a marine geochemist with the University of South Carolina, and started analyzing various phytoplanktons using nuclear magnetic resonance.

“We’ve been fascinated by these phosphonate compounds for a while,” said Benitez-Nelson. “Sonya and I decided that something had to be producing them, and we had to start looking at all these organisms to figure out who it was.”

“After culturing several different kinds of phytoplankton and analyzing them using nuclear magnetic resonance (NMR) spectroscopy, we found high concentrations of phosphonate in cultures of a specific Trichodesmium species – in fact an average of 10 percent of the cellular phosphorus is in the form of phosphonate“, explained Dyhrman. “Ten percent may not sound like much, but this is the most phosphonate ever detected in a marine microbe.”

“When we first saw the phosphonate peak in the Trichodesmium culture, we were stunned, after a 10-year mystery it seemed ironic for Trichodesmium to both consume and produce this compound“, said Benitez-Nelson. “We ran it again. We grew them under different nutrient conditions and, sure enough, the results were the same.”

Since nitrogen is scarce in the open ocean, nitrogen fixing organisms like Trichodesmium are imperative to the marine food web. Trichodesmium phytoplankton will not only bring carbon into the food chain by absorbing it from the atmosphere like other phytoplankton; they will also provide the food chain with essential nitrogen due to their ability to absorb nitrogen gas from the air and transform it into a compound that other organisms can use.

“Not only does this solve a mystery about where these forms of phosphorus are coming from, but the fact that it is Trichodesmium has ramifications for how the phosphorus cycle is linked to the cycling of carbon and nitrogen and how those cycles will function in the future ocean,” said Dyhrman.

The Dyhrman and Benitez-Nelson study was recently published in the journal Nature Geoscience.

According to a new research report released by Canadian scientists, American lobsters use jet propulsion to gain extra speed as the walk across the ocean floor. The lobster can produce 27 to 54mN of thrust, which is comparable to that produced by the pectoral fins of proficient swimmers like the Bluegill sunfish (Lepomis macrochirus) and Surfperch (Embiotoca jacksoni).

On the abdomen, the American lobster has tiny paddle-like structures, formally known as pleopods, which it can fan to create a wake that propels it forward. To understand why the lobster fans its “paddles”, graduate student Jeanette Lim and Professor Edwin DeMont of St Francis Xavier University in Antigonish built a mechanical model which replicates the moving parts of the lobster belly.

“No one had actually measured how much force the American lobster’s pleopods could produce,” says Lim. “We just took the abdomen of a lobster, emptied out the tissues, and hooked up eight mini servomotors bought from a robotic toy company in California to the pleopods.”

To image and measure how the plepods affected the surrounding water, the researchers used a technique called particle image velocimetry.

“Once we saw the flow visualisations, we were surprised with how large the wake was,” says Lim, now studying for her PhD at Harvard University in Boston, US. “The pleopods on American lobsters (Homarus americanus) are relatively broad and paddle-shaped compared to pleopods on crayfish, for example. But they are still fairly diminutive and rather flimsy appendages when you consider the size and toughness of the rest of the body. So we were surprised their beating produced a sizable wake with thrust that was on par with forces produced by the fins of some swimming fish.”

The results have been published in the Journal of Experimental Biology.

A previously unknown species of crustacean and two previously unknown species of annelid worms have been discovered during a cave dive near Lanzarote in the Canary Islands off the coast of northern Africa. The discoveries were made by a team of international scientists and cave divers exploring the Tunnel de la Atlantida – the longest submarine lava tube in the world.

The crustacean belongs to the genus Speleonectes in the class Remipedia, while the annelid worms are members of the class Polychaeta.

The crustacean has been named Speleonectes atlantida, after the cave system in which it lives. It looks a lot like its close relative Speleonectes ondinae which was discovered in the same lava tube in 1985. The two crustaceans may have diverged into separate species some 20,000 years ago after the Monte Corona volcano had erupted, forming the famous six-kilometre long lava tube.

Until quite recently, the class Remipedia was unknown to science. The first member of this class was found in 1979 by divers exploring a marine system in the Bahamas archipelago. Since then, 22 Remipedia species have been named and described. Most of them live in Central America, from the Yucatan Peninsula of Mexico through the north-eastern Caribbean. However, two species are instead found in caves in Lanzarote and Western Australia. The existence of these wayward species puzzles the scientists, since it is assumed that these small eyeless cave-dwellers would not be able to simply swim from the Caribbean to West Africa and Western Australia. One theory suggests that this class might be a very old crustacean group that was already widespread 200 million years ago. If this is true, the two species living off Lanzarote became isolated from the Caribbean group by the formation of the Atlantic Ocean.

As mentioned above, members of the class Remipedia live in dark submarine caves and have no eyes. Instead, they find their way around using long antennae. The heads of these predatory crustaceans are equipped with prehensile limbs and poisonous fangs.

The results of the lava cave exploration will be published in a special issue of the Springer journal Marine Biodiversity in September 2009.

The cave exploration team consisted of scientists from Texas A&M University and Pennsylvania State University in the USA, the University of La Laguna in Spain, and the University of Veterinary Medicine Hannover and the University of Hamburg, both in Germany.