I am not sure when this obsession with both small and large things began. One of the earliest photographs of me is in a giant rocking chair. With a big smile on my face, I am dwarfed by the colossal piece of furniture. Sadly, in researching this post I discovered this rocking chair is not the largest. That title is bestowed to a towering rocking chair, a 56.5 feet tall behemoth in Casey, Illinois, not only the world’s largest rocking chair but also the largest chair in all of America. I will of course need to visit, and photograph, myself next to the massive chair. Another photograph to add to my photo collection of myself with oversized objects. The world’s largest Adirondack chair and me…got it. Largest chest of drawers…done. Largest frying pan…visited. Giant 6-foot tall cheese grater…photographed and almost bought. I could go on and on.

I never realized I could get paid for my obsession. I did not at some point in high school realize or declare I wanted a vocation focused on extreme sizes. Nor was such a trajectory flagged as a possibility on those mandated vocational tests. I got flagged for being perfect for cake decorating. No joke. Nothing about decorating tiny or giant cakes. Of course, who would even think you could make a career out of a passion for size, except maybe Guinness World Records? No, I came by it all by accident.

As an undergraduate, I applied for a summer program to conduct research with a biologist. Knowing at the time I wanted to be a marine biologist, I applied to do summer research counting fish on the coral reefs of St. Croix. An unshockingly, popular choice among undergraduates, I did not get the position. My second and third choices were the only other ocean-based projects in the program. When the scientist involved with my second choice project called to invite me to work with him that summer, I didn’t even remember what the project was. I wasn’t really concerned with the specifics of the other projects because how could I not be selected for my first choice, St. Croix, dream project. Opposed to the beautiful tropical beaches of the Caribbean, my destiny would be to work in a windowless lab all summer in Boston. The project didn’t exceedingly interest me at the time as I wanted to be a field scientist and microscopy in the lab sounded…well dull. But working in an air-conditioned lab in the big city sounded better than living with my parents in rural Arkansas working in the intense Southern heat sweating in a factory. So off to Boston I went. Within a few hours of the first day, I fell in love with the project. So much so I asked that scientist, a preeminent deep-sea biologist and expert on the body size of marine invertebrates, if I could pursue a doctorate with him.

In the biological world, size is more than a novelty. How an organism relates to the world around it is determined by its size, and understanding what influences size is key to understanding the diversity of life itself.  That summer I measured the size of 100’s of tiny snails and when I returned to pursue my Ph.D. I measured thousands more. In total I measured 14,278 deep-sea snails. The largest no bigger than Abraham Lincoln’s head on the face of the penny. The smallest the size of his nose. Those snails I measured were collected from off the coast of New England from depths of over 600 feet to well over 18,000 feet, from the shallows of the New England continental shelf to the abyssal plains.

Why would anyone measure close to 15,000 snails? In the late 1800’s Henry Nottidge Mosely wrote: “Some animals appear to be dwarfed by deep- sea conditions.” By the 1970s, Hjalmar Thiel of Universität Hamburg observed that the deep sea is a “small organism habitat.” Increased depth typically translates into less food in the oceans with the deep-sea being a very food poor environment. As you might expect this has profound effects on the body size of deep-sea animals. Thiel’s seminal 1975 work demonstrated that with increased depth, smaller organisms became more dominant. At depths greater than 4 kilometers on the vast abyssal plains where food is extremely limited, you find some of the most diminutive sizes. In a particularly striking example of this, my doctoral advisor Michael Rex and I calculated those nearly 15,000 deep-sea snails I measured could fit completely inside a single Busycon carica, a fist-sized New England knobbed whelk found along the coast. But by measuring all those snails, Mike and I were able to document exactly how size in these snails changes over a 3.5 mile increase in depth. That study was the first of its kind and remains the largest number of deep-sea animals ever individually measured.

But to say that all creatures of the deep are miniaturized overlooks the complexity of size evolution in the deep sea. Some taxa actually become giants. The Giant Isopod, a roly-poly the size of very large men’s shoe, and sea-spiders the size of dinner plates, quickly dispel the Lilliputian view of the deep sea. Although all those deep-sea snails are smaller than their shallow-water relatives, shockingly Mike and I also found that they actually increase in size with greater depth and presumed lower food availability. To further confound the situation, other scientists have reported the exact opposite pattern in other types of snails, whose size decreases with depth. The same appeared to be true in other taxa, such as crustaceans. How can the deep-sea be both a habitat of dwarfs and giants?

To answer that, I turned from the Earth’s largest habitat to one of its smallest—islands. On islands both giants and dwarfs exist. The diminished kiwi and the enormous Moa of New Zealand, the colossal Komodo dragon on the island of Komodo, the extinct pygmy elephants on the islands of the Mediterranean, the ant-sized frog of the Seychelles, the giant hissing cockroach of Madagascar and the giant tortoise of the Galapagos represent just a few of the multitudes of size extremes on islands. In 1964, J. Bristol Foster of the University of East Africa demonstrated that large mammals became miniaturized over time on islands. Conversely, small mammals tended toward gigantism. This occurs with such frequency that scientists refer to it as “Foster’s rule” or the “Island rule.” Big animals getting small and small animals getting large.

My colleagues and I discovered a similar pattern in 2006 between shallow and deep seas. As shallow-water gastropods evolved into deep-sea dwellers, small species became larger and large species became smaller. Interestingly, size did not shift in a parallel manner. Larger taxa became disproportionately smaller sized—that is, both converged on a size somewhat smaller than medium. I’ve since observed this pattern in radically different taxa, such as bivalves, sharks, and cephalopods.

The fact that islands and the deep sea have so little in common represents a wonderful opportunity that allows elimination of several hypotheses. Of course, what the deep sea lacks is food. The absence of sunlight precludes plants.   Thus, for the majority of organisms living there, the food chain starts with plankton, dead organisms and other organic debris descending from the ocean’s surface. Less than five per cent of the total food available drifts to the sea floor, leading to an extremely food-limited environment. On islands, less food is available because the small land areas support fewer plants at the base of the food chain.

In either case, island and deep-sea animals need to be efficient and creative in their acquisition of food. In both habitats, there may not be enough total food to support populations of giants only. Unable to travel long distances to search for food or to store large fat reserves to fast through periods of food scarcity, smaller organisms are also at a disadvantage. If these contrasting evolutionary pressures were equal, size would be driven to an intermediate. However, the selection against larger sizes is greater, leading toward an evolutionary convergence that is slightly smaller than the intermediate size. Thus, differential responses to food reduction by different- sized organisms may resolve the outstanding paradox of divergent size patterns in the deep. In the interests of reaching this ‘golden medium’, some species become giant while others miniaturized.

In that summer of 1996, as a clueless undergraduate, I started my scientific adventure that fueled my obsession with size. Two decades later, I still am excited by the body size of animals. Much of my research, and the students who work with me, is dedicated to understanding how the expansive variety of sizes on Earth from bacteria to blue whales emerged. Did I mention the great selfie I took recently with a giant whale vertebra the size of coffee table?

The post Craig With Big Things (and Small Things) first appeared on Deep Sea News.

When it comes to ocean outreach, Dr. M is a giant: a rum-loving, goggle-wearing outreach giant, one with whom I had the pleasure of working on his most massive (though by far not his only) science-meets-outreach success. Dr. M was the lead author on a groundbreaking 2015 review paper called “Sizing Ocean Giants,” cataloging the largest members of many marine animal groups. He was kind enough to include me as a participant, and the experience was beyond inspiring. I’ve never seen someone so seamlessly integrate teaching, outreach, and research, and all with remarkable results.

Best I can tell from sleuthy internet sleuthery, Dr. M first realized there was a need for such a paper sometime around 2006, a full nine years before publishing “Sizing Ocean Giants” (talk about commitment!) Why do think 2006 was the golden year? Because he wrote about it, briefly, in a 2011 article for Wired on the value of taxonomists:

In 2006 I set out to explore how biodiversity and body size were linked among animals. To do so I needed information on the largest- and smallest-sized species for each group of animals — something surprisingly not readily garnered from the published literature.

So what did he do? He published the literature. How? He lead a team of five undergraduates on a semester-long adventure to solve the mysteries of the biggest ocean beasts. All five undergrads earned authorship on the paper. In conceiving the idea, Dr. M had a teaching vision:

The students would become experts on their individual animals. Part of that coming about by searching the literature for body size data. Part coming from sharing that knowledge with the public. I would ask each student to contribute blog posts to storyofsize.com and that would serve as our core of outreach. I would require each student to engage the science community and public via Twitter.

But the really amazing part, at least to me, is that it worked. I mean, it’s a beautiful idea, but actually pulling it off? Dr. M made it happen, coordinating his team of five students and 10 scientists to publish the 69 page manuscript, complete with publicly available dataset and computer code to back it. The paper rapidly became one of the journal’s top marine biology papers. Science, education, outreach: I’ve heard a lot of people talk about ways to combine these goals, but Dr. M did it, and he did it beautifully.

And the thing is, I don’t really know if Dr. M appreciates just how impactful his outreach is. My experience with Sizing Ocean Giants left a lasting impression. When it was all over I thought, ‘I want to do that some day. I want to be like that guy.’

And I’m not the only one. I wasn’t even looking for examples of people whose lives have been changed by Dr. M when a friend of mine told me this:

I read [DSN] at 15 and it made me want to do what I do. Way back when it was part of this amazing community of science bloggers called “Science Blogs”- I subscribed to DSN, as well as many others through Google Reader (this amazing, now non-existent RSS aggregator). I followed them through their migration…for this science obsessed teenager, this was the perfect place for me to read about things I was fascinated by. I wanted to be a marine biologist, but this helped to narrow the scope, and here I am!

She is now a PhD candidate studying deep-sea animals.

I don’t know how many people Dr. M has touched with his humor, dedication, and intellect. But counting me and my friend–well that’s two right there. Add to that all the folks he has reached through Sizing Ocean Giants and Deep-Sea News? I bet my friend and I are in good company. So thank you Dr. M. Thank you for your Giants paper, thank you for your leadership, thank you for helping to change science outreach for the better.

The post Dr. M: An Ocean Outreach Giant first appeared on Deep Sea News.

The following post is authored by Leo Gaskins as part of the Sizing Ocean Giants project. This post originally occurred on the Story of Size

1. They are sleek yet functional.

The aesthetics are impeccable, and signal just how well designed these sharks/smartphones are. Blackberry is one of the most easily-recognizable brands out there, and not for nothing. Its streamlined body and keyboard allow it to fit comfortably in a hand and allow the user maximum typing speed.  Great Whites are also instantaneously recognizable, with a signature body shape.  Their two-toned shading isn’t simply a fashion statement, but serves as a cloaking technique. Called countershading, their darker upper half makes them harder to spot from above, and their white lower half makes their outline less distinguishable from below.

2. They are lightning fast.

They have the physical or processing power to get the job done. Their goals may different, but their pace is legendary. Those cute seal pictures you got form your friend? Blackberry, on 4G LTE, has it downloaded in seconds. That cute seal out swimming in the ocean? Great White Sharks, moving up to 40 kilometers per hour, with 18,000 Newtons of bite force, rip those seals to shreds in seconds.

3. They are addictive.

Remember in the mid 2000’s when the phrase “Crackberry” was common slang? People were glued to their smartphones then as they are today. Having the ability to email or bbm your friends with the press of a few keys, from anywhere, was a total luxury. Great Whites, on the other hand, are addictive to us in a different way. They pique our curiosity about the unknown. Shark week shows don’t change all that much each from year to year. It’s not as if there are hundreds of new stories of people getting killed or mauled annually by our cartilaginous friends. Yet each year, we find ourselves on our couches, completely captivated for a week, hearing about the same narrow escapes from the jaws of the most powerful ocean predator.

4. Their populations are in decline.

The IUCN Red List categorizes Great White Sharks as vulnerable.  They are threatened for several major reasons. They are by-catch in commercial fishing, illegally hunted for jaws and teeth, are experiencing habitat destruction in their nursing grounds, and are killed before they reach sexual maturity.

If there were IUCN Phone List, Blackberry would be listed as critically endangered. The reasons for its decline, however, would be a misjudgment of demand coupled with overproduction of products, a store missing prominent and popular apps, and inability to compete with similar products.

5. They are irreplaceable.

The bottom line is that, for both to have survived and flourished for these intervals, they had to have characteristics that made them distinctive. For Blackberry, their incomparable keyboard and messaging systems were the hallmarks of their success. For Great Whites, their unparalleled adaptations, such as their ability to detect even incredibly sensitive electrical field pulses, intelligent stalking and capture of prey, and overall unrivaled strength and agility, are the hallmarks of their success as a species.

But as we’ve already seen with Blackberry, the population can crash in a relatively short time span. With quickly shrinking resources and support, this brand is losing its footing quickly, and no one seems to be stepping in to save it. Its loss signals the end of keyboard phones in favor of touch screen, and imitators couldn’t properly fill this vacuum. The same is true with Great White Sharks. They fill an important niche, as the apex predators of the ocean, and without them, there will be a ripple effect throughout the food chain.

We all know Blackberry well. We understand exactly what is being lost, and how to cope and compensate with alternate strategies. But with Great White Sharks, we would be losing an object of unknown and limitless importance, and like the virtual keyboard, the second best thing would never be quite the same.

It’s been nice knowing you, Blackberry.

Resources:

Austin, RA. “How Fast Can a Shark Swim?”. ReefQuest Centre for Shark Research. Retrieved 2013-10-01.

Fergusson, I., Compagno, L.J.V. & Marks, M. 2009. Carcharodon carcharias. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1. <www.iucnredlist.org>. Downloaded on 02 October 2013.

Gottfried, M. D.; Fordyce, R. E. (2001). “An associated specimen of Carcharodon angustidens (Chondrichthyes, Lamnidae) from the Late Oligocene of New Zealand, with comments on Carcharodon interrelationships”.Journal of Vertebrate Paleontology 21 (4): 730–739.

The post 5 Reasons Why Great White Sharks are the Blackberry of the Seas first appeared on Deep Sea News.

The superhero like swimming of Manta Rays

What’s black and white and studied all over?

The post Whale Shark and Manta Ray Gif Roundup first appeared on Deep Sea News.

The following post is authored by Catherine Chen as part of the Sizing Ocean Giants project. This post originally occurred on the Story of Size

Sixty million times. That’s really big, but just how big?

• 60 million kilometers is almost half the distance from the Earth to the sun.
• 60 million times bigger is a baby born at 7.5 pounds growing to 450 million pounds
• … or $60m is a measly 0. 00035% of America’s debt. Hah. Anyway.

So 60 million is big enough that it’s hard to conceptualize (and as it turns out, provide interesting examples for) and doesn’t seem all that relevant. Except…

Enter the ocean sunfish (Mola mola, Latin for millstone), possessor of what must be one of the derpiest faces in the animal kingdom. Heck, it’s not even only the face. Just look at the dang thing:

It’s been called the Eeyore of the ocean, which I think is a bit of an insult to Eeyore, because at least he’s got a proper tail. But turns out that for all its silliness, the mola manages to grow a whopping 60 million times its original size during the course of its lifetime. That’s one freaking big Eeyore.

Mola actually start as small bizarre-looking tiny 2.5mm long larvae, although it’s been estimated that the eggs are approximately 1/20^th of an inch, or 1.25 millimeters. The little Molas have a long way to grow.

That cute little guy can become this:

Whoa.

And although the lifespan of a wild Mola is unknown, that’s still an awful lot of growing in not all that much time. In captivity, a young Mola grew a staggering 823 pounds (373kg) in a little less than three months, before its keepers rightly decided it needed to be released while they still had the ability to transport it safely to the ocean.

The biggest ocean sunfish ever found was an unfortunate fellow who hit the steamship the SS Fiona in 1908 with a “violent concussion.” (One can only imagine that the fishermen aboard the boat were rather alarmed at the giant thud that must have occurred.) After being towed to shore, the fish was measured to be 3.1 meters in length, 4.26 meters tall, and supposedly weighing 4927 pounds. Molas have consequently been graced with the well-deserved title of the world’s largest bony fish by the Guinness Book of World Records.

Their large size leads to some interesting results. For starters, how on Earth do creatures this big control their buoyancy? That is, why don’t they sink like rocks? After all, they lack the swim bladder that so often controls that job in other fish. The Mola has developed its own method (of course, because this fish isn’t special enough as is) for avoiding the fate of permanently sinking into the depths: a thick layer of gelatinous tissue surrounds the whole fish. This subcutaneous layer has been found to be as thick as 0.21 meters and to make up as much as 44% of the Mola’s  body mass.

Their huge bulk has also led to a rather unexpected consequence: viewed from a distance, a Mola swimming along is sometimes mistaken for a shark, (why you gotta be so sneaky mola?) with their large fins and bodies. However, any matter of time spent watching that fin approach is likely to replace the vague fear you feel with amusement instead. The way that the sunfish move their bodies along is uh, distinctive, and really, their swimming just looks so wrong (especially if you’re expecting a sleek shark).

Instead, you get this:

The synchronous movement of the dorsal and anal fins manages to propel the mola along at a decent clip of 0.4-0.7 meters per second, similar to the speed of other large fishes such as salmon and marlins. Who woulda thunk? Biologists used to believe that their shape meant that molas were slow awkward swimmers, but now those darn creatures have gone and proved everyone wrong.

It’s okay, at least we’re still way better looking.

• To read the original article that first suggested the figure of 60 million, check out Gudger’s appropriately titled “From Atom to Colossus.”
• The first aquarium to keep Molas in the United States was the Monterey Bay Aquarium, where the mola that grew at an astronomical rate was kept. Read the original story in A Fascination for Fish: Adventures of an Underwater Pioneer by David Powell (2001).
• Interested in the speed of the sunfish and its gelatinous layer?
• For a great overall review of what we currently know about the Mola mola, refer to Pope et. Al 2010.
• For more Mola entertainment check out my twitter @catherine_chenn

The post Ocean Sunfishes: The Eeyore of the Sea first appeared on Deep Sea News.

The following post is authored by Caroline Schanche as part of the Sizing Ocean Giants project. This post originally occurred on the Story of Size

For those who have seen elephant seals up close and personal, there is no questioning the fact that elephant seals are not afraid to put on the pounds. This guy surely doesn’t seem to mind his blubbery appearance:

In other words, there is a whole lot of fat on them. However, the word fat does not do them justice, so I took the liberty of looking up some synonyms (from thesaurus.com). Therefore we can also call elephant seals bulging, bull, butterball, chunky, heavy, hefty, heavyset, husky, meaty, plump, distended, solid, stout, swollen, beefy, brawny, burly, gargantuan, and my personal favorite: jelly-belly.

So sit back, relax and enjoy, as elephant seals show us the benefits of being a butterball.

1. Stay toasty

Elephant seals are the largest of all seals. The southern elephant seal Mirounga leonina can grow to be 8,800lbs and 20 ft long. In adult males, up to 50% of this mass comes from blubber, which is a thick layer made up of fat which has a dense system of blood vessels and lymphatic vessels. Since it is a thicker layer and contains more blood than normal fat layers, it provides a ton of insulation and is one of the main methods for thermoregulation. In other words, these elephant seals will stay warm and toasty all year long. More blubber means more thermoregulation, therefore bring on the brisket because its time to eat. Interestingly, some humans actually do need to do something similar when travelling to extremely cold places such as Antarctica to maintain warmth and to not become severely underweight, although hopefully they don’t get to super-sized conditions.

 2. Get them Ladies

Larger elephant seals get more girls. It really is that simple. When the seals arrive at a beach for mating season the males all battle it out to find out who’s the boss: the alpha male, or the beach master. Elephant seals are known for this fighting and it usually goes a little something like this:

The beach master is the one who gets to copulate (not my favorite word) with the most females, which is exciting for him I guess. Does this apply to us? Is it always the biggest (read: chunkiest) guys who are more likely to get lucky? ehhhh, I’d have to go with no. If we’re talking muscle it might be different, but in this case the seals are a whole lot of blubber. Not my thing, but maybe its exactly what a female elephant seal wants.

3. Dive Deep into the Blue

Elephant seals dive very deep down to get to their favourite food sources of skates, rays, squid, octopus and eels. They can spend almost 90% of their entire day underwater and can swim down as deep as 300m! How can they do this? Well, all those blood vessels in the blubber as well as an unusually high blood volume along with higher levels of haemoglobin and myoglobin allow them to have a very high oxygen storage capacity. Kind of a cool thing to be able to do.

4. Be Your Own Buffet

All that blubber is good for a lot of things, but one of the best is that the seals can live off of it for months during mating season. Although at the end of it both the males and the females can have lost as much as a third of their body weight, they are still living the life if they don’t even have to worry about food. They have a specialized metabolism with water as a byproduct, and can live off the food stores in their blubber all mating season long, giving them time to focus on… other things.

I know I can get lazy when it comes to making food sometimes and it could be nice to have a fat store to keep you from getting starved, however with us it doesn’t really work that way. Getting fat doesn’t keep you from eating, although I wish it did.

 5. Do the BlubbrBounce

Elephant seals clearly need their blubber so that they can present this masterpiece to the world:

6. Get away with being an scumbag

All week I have been tweeting about the scumbag elephant seal (shameless plug: @carolinetime9), because their large size and certain things they do could be considered particularly “scumbaggy” (see below).

However, no matter how much of an scumbag you are, nobody, and I mean nobody, is going to try to mess with you if you look like this:

Therefore, their size and intimidating (read: ugly) appearance means they can do whatever they want (at least the alpha males can) because very few can take them on.

To conclude, I think Elephant seals clearly make their mass work for them, and are arguably one of the species that can pull off such a great amount of blubber. They have good reasons for their bodacious, unlike us humans. Some might disagree though:

References

Haley, M.P., C.J. Deutsch, and B. Le Boeuf. “Size, Dominance and Copulatory Success in Male Northern Elephant Seals, Mirounga Angustirostris.” Animal Behaviour 48 (1994): 6. Print.

LeBoeuf, Burney J. Elephant Seals: Population, Ecology, Behavior, and Physiology. Berkeley, Calif. [u.a.: Univ. of California Press, 1994. Print.

http://www.parks.ca.gov/?page_id=1115

https://sites.google.com/site/elephantsealnotes/physical-characteristics

Battle of the living instrument platforms: Elephant Seals vs Narwhals

The post Six Reasons to Supersize first appeared on Deep Sea News.

The following post is authored by Caroline Schanche as part of the Sizing Ocean Giants project. This post originally occurred on the Story of Size

Would you convert to a diet of cucumber? Could you do what the leatherbacks have done?

None of us can really imagine surviving solely on foods such as cucumber or celery. They are about 95% water, and come in at about 8 calories per 50 grams. In order for an adult to consume the recommended 2,500 calories a day on a diet based solely on cucumber, they would have to consume 15.625kg of it every single day. Yummy. Considering a cucumber weighs around one kilo, you would have to consume almost 16 cucumbers a day, and nothing else. Seems like a lot of work doesn’t it? Well the leatherback sea turtle, Dermochelys coriacea, is the largest living sea turtle and gets to its massive size on a similar diet composed of a mainly water-based organism: jellyfish.

Although we consider eating mainly water-based foods as the road to losing weight, eating jellies is what makes these gorgeous giants able to obtain their impressive size. Starting off as tiny hatchlings at about 3 inches, they must then gain enough energy and nutrients from these jellies to grow to be on average 4-6 feet, as well as to support their high energy demands as a highly migratory species. Leatherbacks are actually record holders in migration, as they travel over 10,000 miles a year. How can they have enough energy to support this migration when all they eat is jellyfish? If I don’t get my carbs and protein I get very grumpy very fast, and I would certainly not be in the mood to cross the Pacific Ocean.

Jellyfish are mainly made up of water with a few proteins and some minerals, but not much else other than those nasty nematocysts (stinging cells). Still, the largest leatherback ever recorded weighed around 916kg. How do these giants eat enough jellies to grow to such incredible sizes? Their secret lies in their esophagus.

Our friend the leatherback has an awesome esophagus for two reasons (never thought I would refer to an esophagus as awesome, but I give credit where credit is due). The first is that it is unusually long. The esophagus of a leatherback is not a straight tube directly to their stomach as ours is, but rather it keeps going past the stomach all the way to the rear of the turtle before looping back up to connect to the stomach which still lies closer to the front. This long tube provides extra storage for jellies before they even reach the stomach, and so there is a continual supply of food being pushed into the stomach for digestion. Sort of like a storage conveyor belt of food.

The best part about having jellyfish as your main prey is that they are not very difficult to catch. All the leatherbacks really need to do is find the jellyfish to feed on them, as they will never evade an attack due to their slow nature.  Lion’s mane jellies are found in big groups in Canadian waters in the summer months, so finding them is not an issue. This, plus their conveyor belt-like esophagus ensures the leatherbacks are able to pack in around 73% of their own body weight, which is several times more than they actually need to survive, according to one study (Heaslip 2012).

However, wouldn’t you think there would be some issues in eating jellyfish in general? Some people do make dishes containing this mushy creature, but I plan to hold off for now. The second adaptation of the Leatherbacks’ esophagus is aimed at helping them hold onto the jellies, as well as to protect them from their stinging juices. This adaptation takes the form of esophageal papillae, which are prongs made of cartilage that line the mouth, throat and entire esophagus of the turtle. These papillae hold the jellyfish in while the sea turtles expels salt water from its throat, as well as making sure the nematocysts do not harm the turtle. Pretty cool stuff.

WARNING: If you want to maintain your image of sea turtles as the cute and cuddly, peaceful and graceful creatures we all know and love, you may want to scroll through these pictures with your eyes closed, as their papillae tend to make the leatherbacks mouth look a little like the mouth of the Kraken. Stuff of nightmares right here:

When I first saw this picture, it left me kind of like this:

And a little like this:

Overall, Leatherback sea turtles have figured out some very interesting ways of obtaining and maintaining their massive size on a diet of a mainly water-based organism. However, its particular diet is also part of why this critically endangered animal is in serious trouble. Trash in our oceans has become a huge problem, and floating plastic bags that resemble jellyfish can be a real threat to this impressive creature. Thankfully, several organizations have started campaigns about ocean trash; one specifically about plastic bags has gone viral (pictured below from medasset.org), and I encourage you to check out their organization and the important work they are doing to preserve this amazing species.

Hopefully the future of this gentle (but sometimes scary-looking) giant takes a positive turn and we get to keep the Leatherbacks around for a little (a lot) longer.

Heaslip, S.G., Iverson, S.J., Bowen, W.D., & James, M.C. 2012. Jellyfish Support High Energy

Intake of Leatherback Sea Turtles (Dermochelys coriacea): Video Evidence from Animal-Borne Cameras.PLoS ONE 7(3): e33259. doi:10.1371/journal.pone.0033259

Ruckdeschel, C., & Shoop, C.R. 2006. Sea Turtles of the Atlantic and Gulf Coasts of the United States. Species accounts: Leatherback (pp35-51).Athens, Georgia: University of Georgia Press.

http://www.seeturtles.org/1895/sea-turtle-migration.html

Sea Turtles! Part 3: Leatherbacks, Loggerheads, and Greens.

The post Growing Large on Jelly first appeared on Deep Sea News.

What I want to discuss, and I use this word specifically as after 10 years contemplation I seem no closer to an answer, is why the Giant Isopod is, well, giant?

Mosely noted in 1880

Other [animals] attain under them gigantic proportions. It is especially certain crustacea which exhibit this latter peculiarity, but not all crustacea, for the crayfish like forms in the deep sea are of ordinary size. I have already referred to a gigantic Pycnogonid [sea spider] dredged by us. Mr. Agassiz dredged a gigantic Isopod eleven inches in length. We also dredged a gigantic Ostracod.

For over a 125 years, scientists have contemplated the extreme size of Bathynomus giganteus. Do other isopods attain these sizes? Gigantism is also known in the isopod Serolis but enlargement comes from flattening. B. giganteus appears unique in its extreme gain in bulk.

Why the increase in size? Timofeev (2001) proposed that deep-sea gigantism, for all crustaceans, reflects colder temperatures leading to longer lifespans and thus larger sizes as these beasties continue to grow . However, despite little changes in temperature beyond the thermocline, deep-sea invertebrates including isopods continue to show changes in body size.  Alternatively, Chapelle and Peck (1999 and 2004) demonstrated  size was related to oxygen concentrations. It is suggested this relationship arises because the amount of oxygen available controls the amount of sustainable tissue. This has been shown experimentally in which cell size and cell number both increase with increasing oxygen concentration (Frazier et al. 2001). Larger sizes in snails are also found at more oxygenated sites in the deep sea (McClain and Rex 2001). However, giant isopods are known from the Gulf of Mexico deep where oxygen concentrations are low.

Kevin Zelnio in an old post also brought up another interesting point….

B. giganteus is a scavenger (3, 5, 6), but some suggest it is also a facultative predator (3, 6). Specimens in aquaria have survived 8 weeks between feedings (5) and it speculated that this may be an adaptation for carrying its brood, which would be severely impacted by a full stomach (3). Further support for this hypothesis are the large quantities of lipid reserves in the hepatopancreas (14) and fat bodies (2) of this isopod.

Alternatively, the larger size also increases fasting potential because greater fat reserves can be maintained. Larger size also confers a greater area for feeding, important for either a scavenger or a predator.  Both of these are important adaptations in the food-limited deep sea.

Of course all of this is speculative and it remains unclear why Bathynomus is unique among arthropods. Perhaps is size is simply a random walk in evolution and is nonadaptive. Gould noted in reference to another body size pattern, Cope’s Rule…

One would think that issues so fundamental, and so eminently testable, had been conclusively resolved long ago-except for a perverse trait of human psyche. We tend to pick most ‘notable’ cases out of general pools, often for idiosyncratic reasons that can only distort a proper scientific investigation

Is this case for the Giant Isopod? But perhaps the most interesting question is why the Giant Isopod is not larger?

The post Why isn’t the Giant Isopod larger? first appeared on Deep Sea News.

Sure that is all great but what paper so big it rivals an ocean giant?  Well you are in luck!  The 69-page tome is available!  But the best part for you is that the paper is published in PeerJ so it is completely open access and available to you for free. That’s right completely free!

But you want more?  How about a super team of authors?  What about a team of science super heros on Twitter?  Needless to say collecting all the known size data and literature on the sizes of all these animals is a herculean effort.  It’s one part a databasing effort and one part historical research going through the literature, museum specimens, talking with other scientists and collectors, and even checking Ebay for specimens for sale.

The effort was not singular and included the massive efforts of five undergraduates–Catherine Chen, Leo Gaskins, Frank Lee, Caroline Schanche, and Shane Stone.  A cast of thousands helped us fill in the gaps.  A lot of the authors are on Twitter so feel free to reach out to them (@clschanche @ccfrankee @catherine_chenn @realshanetrain @MegBalk @AlistairDove @RebeccaRHelm @TrevorABranch @SFriedScientist @DrCraigMc

Hey you want size data?  And some statistical code to generate some cool body size plots.  We got that too! You can download from Dryad all the data and R-code to analyze, plot, and just generally play around with the data yourself.

And as bonus, because we love you all, we have an inforgraphic with all of your favorite ocean giants and their largest known sizes to download.

McClain, C.R., M.A. Balk, M.C. Benfield, T.A. Branch, C. Chen, J. Cosgrove, A. Dove, L.C. Gaskins, R.R. Helm, F.G.E. Hochberg,, F.B. Lee, S.E. McMurray, C. Schanche, S.N. Stone, and A.D. Thaler (2015) Sizing ocean giants: patterns of intraspecific size variation in marine megafauna. Peer J2:e715; DOI 10.7717/peerj.715

The post Sizing Ocean Giants: The Paper! first appeared on Deep Sea News.

Mantas are shape shifters and elastic, a cross between Mr. Fantastic and Mystique

In rays, the pectoral fins are greatly expanded and fused to the head.  This forms a broad, flat disc, that can be manipulated to create a variety of shapes.  The wing skeleton is actually composed of many repeating cartilaginous elements. Although the range of motion between any two adjacent elements is a mere 15˚, there are enough adjacent elements for the wings to actually touch behind their backs.  The wings are literally hinged at thousands of different points.

Mantas can fly like birds, like Warren Worthington III or Northwind

Rays swim by either oscillation or undualtion of the fins. Rays like in the video below move by passing several waves along the fins, i.e. undulation.  Think a sinusoidal wave.  The Manta ray in the above video swims with a flapping motion much like a bird, i.e. oscillation, with 1 or less waves passing along the wing.

The flapping in Mantas can generate amazing amount of propulsion.  The musculature that powers swimming originates toward the center of the ray and inserts onto each consecutively arranged radial.  Each radial acts a cantilevered beam and transfers the force of the muscle to all of the individual skeletal elements.  This allows for considerable power.  Imagine trying to move a flexible 4 foot by 8 foot plywood sheet through the water and you can begin to understand the strength this takes.

With this power, a Manta can move almost an entire body length every second.  A 15-foot Manta would move at a speed of around 9 miles per hour, nearly double Michael Phelp’s fastest swim.  Mantas are even capable of reaching bursts of 22 miles per hour, twice the top speed of my first used car.

Mantas can control water, like Katara, Sailor Mercury, or Mera

The oscillatory motion of the wings in Manta creates vortices of water that produce thrust forward.  Manta’s may also produce special kind of effect called a leading edge vortex.  This vortex of water, along the front plane of the manta wing can generate considerable thrust and “suck the wing up.” The vortices adhere to the leading edge of the wing and body and eventually roll of the wing tips.  The spiraling of these vortices creates water movement in the reverse direction.

UPDATE: Gabriel Weymouth, who studies computation, fluids, and biomimetics at the University of Southampton, sent me link via Twitter of his stingray simulation of undulation swimming.  In the video below you can see the leading edge and tip vortices.

The post The superhero like swimming of Manta rays first appeared on Deep Sea News.