Sleeping Beauties

Imagine yourself cruising down the road at night. There's no moon so, so you're driving slowly, peering into the blackness to find your way. As your eyes adjust you see a gigantic, ancient woman sidle into the glare of your headlamps. She's slow and battered, and moves almost as if she's in a trance. You slow down even more to avoid hitting her, but you can't bring yourself to get out of the vehicle. As she meanders to the edge of your lights' beam she turns slightly, and you catch a glance at her eyes. A tubular creature dangles from two filaments embedded in her cornea. Though she's surely been blinded by the parasite you sense that she can feel you there. As she's enfolded back into the darkness you wonder was she an ancient spirit? An aesthetic hiding away from society? A witch? or even a zombie?

She was a shark.

Courtesy: NOAA Photo Library via Flickr

In our imaginary scenario you're a researcher with the US' National Oceanic and Atmospheric Administration. You're cruising along in a submersible when a species of sleeper shark swims in front of your vehicle. 

There are only around six species of sleeper sharks that we know of, and two of them fit the bill for this story; the Pacific sleeper shark (Somniosus pacificus) and the Greenland shark (Somniosus microcephalus). Although their cousin the southern sleeper (Somniosus antarcticus), which lives around Antarctica and is so badass it eats juvenile colossal squid, comes close it doesn't fit our story because it isn't affected by the dangling parasite; which we'll talk about later.

Pacific sleeper and Greenland sharks are truly incredible. They're massive. Adults of both species average around 4 meters; that's about 14ft, but they can grow even larger. That size is on par with all the largest predatory sharks we're more familiar with. 

I'm gonna go ahead and guess this kid is not

the one who reeled in this shark

 Courtesy: Wikimedia Commons

Unlike great whites or tiger sharks, which are fast, active predators, sleeper sharks are sluggish. It's believed that they hunt by sneaking up on live prey. They move so slowly, about the same speed as a crawling baby, and are so hydrodynamic that they barely disturb the water. So when prey are distracted or at rest they don't notice these incredible predators. Not only can sleeper sharks hunt, but they're also effective scavengers. Researchers have found meat in sleeper shark stomachs that's crawling with the organisms that usually consume dead flesh on the ocean bottom. We also know from stomach contents that sleeper sharks will consume seals, dead whales, fish, and even polar bears! It's not clear if the polar bear was an individual that drowned while crossing sea ice or if it was taken live, but either way....wow. Even crazier, a couple of guys in Newfoundland, Canada found a stranded Greenland shark that had 2 feet of moose tissue stuffed down its gullet! 

Little Known Fact: Hastily gobbled moose is 

the national dish of Canada

Courtesy: Christian Heilmann via Flickr

Now this slow lifestyle has benefits besides giving sleeper sharks the ability to hunt or scavenge literally everything. Sleepers are found in cold waters, either at the poles or deep in the ocean. In fact, Greenland sharks are the only shark species known to live under the arctic ice cap. In frigid waters it's easier to survive with a slow metabolism because with a fast one you're constantly compensating for lost heat. Plus a slow metabolism means you can live for a really... really... really... really long time.

A study published in Science used radiocarbon dating of the core of Greenland sharks' eyes to predict the age of a variety of individuals. This technique suggests that really old Greenland sharks may be 272-512 years old! If that's the case they're the longest lived vertebrate on earth, and there are sharks alive today older than the United States. 

"Suck it Methuselah!"

Courtesy Public Domain via Encyclopedia of Life

The downside to growing to that great age is that sleeper sharks probably don't reach sexual maturity very quickly. It's been estimated from the development of ovaries and testes in dead sleepers that they can't reproduce until they're 10 or more feet long. Greenland sharks are thought to grow so slowly that they might need 150 years before they can get to baby making. If that's the case then these fish may be very sensitive to overfishing. Sleepers are commonly caught as bycatch in fisheries for other species, so it's very important to use programs like Seafood Watch to ensure your fish comes from sustainable sources.

In Iceland there is a small targeted fishery for Greenland sharks because they're the main ingredient in one of Iceland's traditional dishes. Hakarl is Greenland shark that's been fermented for several weeks. It has to be fermented because sleeper shark meat contains a lot of Trimethylamine-oxide; which is toxic. It's so poisonous that sled dogs, ravens, and a sea birds called fulmars have been described as getting "shark drunk" after eating too much raw shark. The symptoms include stumbling, respiratory depression, erratic behavior, and vomiting.

Pictured: Shark Drunk

Couretsy: Schroder + Schombs PR via Flickr

The Trimmethylamine-oxide probably helps protect sleeper sharks from the challenges of living in the deep and polar ocean. The chemical counteracts the protein dismantling effects of high pressure at depth, and works like anti-freeze to prevent the sharks body from locking up.

Okay so all of these adaptations make sleeper sharks a pretty good match for the woman in the creepy story from the introduction, but what was that bit about the parasites on her eyes? Well I'm both glad you asked and horrified that you reminded me.

Pacific sleeper and Greenland sharks frequently host the parasitic copepod (pronounced: co-puh-pod) Ommatokoita elongata. One study found that up 85% of Greenland sharks have these creepy-crawlies living on and in their eyeballs. The copepod, which is a crustacean related to shrimps and crabs, inserts a stud called a bulla into the shark's eye and just kind of dangles from it. As it swings there for its entire life the copepod feeds on the juices from the shark's eyeball. It also scratches the ever living heck out of the cornea as it moves around. It's no surprise that these copepods commonly blind their hosts. However, sleepers don't seem to be affected by blindness at all. It's believed that sleepers rely on their other senses so much that they don't actually need their eyes.

      

I propose the common name of the "Why-God-why-does-this-exist!? copepod"

Courtesy: Johnathan Wojcick via bogleech.com

While sleeper sharks are certainly bizarre, they're also a magnificent example of adaptation to challenging conditions. They're probably the longest-lived of all vertebrates, they know how to take their time and move deliberately, they enjoy a place of respect in the food web, and they survive adverse conditions every day. Not only that, but if you're a little loose with your Latin translation, Somniosus microcephalus means "sleepy, little face". That's pretty adorable for an animal most might not call a sleeping beauty.

References:

Borucinska, J.D., Benz, G.W., & Whiteley H.E., "Ocular Lesions Associated with Attachment of the Parasitic Copepod Ommatokoita elongata (Grant) to Corneas of Greenland Sharks, Somniosus microcephalus (Bloch & Schneider), Journal of Fish Diseases, 1998, 21, pg 415-422

Courtney, D.L., & Foy, R, "Pacific Sleeper Shark Somniosus pacificus in the Eastern North Pacific Ocean Inferred from Nitrogen and Carbon Stable-isotope Ratios and Diet", Journal of Fish Biology, 2012, 80, pg 1508-1545

Hulbert, L.B., Sigler M.F., & Huntsford C.R., "Depth and Movement Behavior of the Pacific Sleeper Shark in the North-east Pacfic", Journal of Fish Biology, 2002, 69, pg 406-425

MacNeil, et Al., "Biology of the Greenland Shark Somniosus microcephalus", Journal of Fish Biology, 2012, 80, 991-1018

Nielsen, et al. "Eye Lens Radiocarbon Reveals Centuries of Longevity in the Greenland Shark Somniosus microcephalus" Science, 2016, 353, pg 702-704

No Author, "Moose-eating Shark Rescued in Newfoundland Harbour"(sic), CBC News, Nov 21 2013, Accessed via: http://www.cbc.ca/news/canada/newfoundland-labrador/moose-eating-shark-rescued-in-newfoundland-harbour-1.2434102

Ghost Face Killer (Whales)

December's post got the Depth and Taxa crew thinking. We talk an awful lot about fish and invertebrates on this blog. Of our 32 posts only three directly refer to marine mammals. While it's great that we're bringing the less publicly well-loved species into the spotlight; it's sad because the ocean's mammals are astonishing. Whales, dolphins, porpoises, seals, sea lions, walruses, and sirens (the manatee kind, not the Odyssean) all exhibit remarkable adaptations for a class of animals that arguably don't belong underwater. So in the interest of fairness and the spirit of deeper understanding, let's talk about the biggest, the baddest, the black and white-enest of the dolphins; Orcinus orca, the Killer Whale.

They're like the pandas of the sea! If pandas ate exclusively flesh...

and hunted in groups... and had complex social structures... 

They're like the wolves of the sea!

Courtesy: Matthew Allen via Flickr

Okay so the first thing you might be wondering is how we can call them killer whales if they're dolphins? Well the word "whale" is deceptively complicated. See, back when the common conscious was still in its "everything that swims is a fish phase" a whale was just anything really large that you saw or caught in the ocean. More recently whale has mostly been used to mean any large species of cetacean (pronounced: set-ay-shun). If you've ever called something a whale, porpoise, or dolphin; it's a cetacean. Dolphins are a specific family within the cetaceans, so orcas are both whales and dolphins. 

Just like humans, orcas can be found all over the globe; from the tropics to the poles. They live in groups comprised of their relatives and close associates, just like us. They're the apex predator in their environment, just like us... They live 50-60 years but can get over 100... just...like...us... Hm these similarities are starting to get a bit strange.

Okay, this is officially weird now. 

Courtsey: Douglas Muth via Flickr

 

The truth of the matter is, humans and orcas are both extremely successful because of our large, wrinkly brains and penchant for caring about others of our own species. In humans the prime example of this one-two punch of emotional intellectualism is just how much listening to "Hello"  makes us want Adele to find happiness <sniffles>. In orcas it's their ability to form what are called ecotypes.

There are at least ten orca ecotypes between the northern and southern hemisphere, and likely more to be discovered. Each has its own feeding strategy, typical body type, and associated behavior. Usually more than one ecotype is found living in the same place. Take for example the continental shelf of the northeast Pacific. These nutrient rich waters are home to the kind of expansive seafood buffet usually reserved for Red Lobster and questionable casinos. Fish, birds, mammals, and invertebrates are all in ready supply if you're clever enough to harvest them. This smorgasbord has allowed for three different ecotypes to develop in one region.

Courtesy: Dahlheim et Al. (2008), Marine Mammal Science, 24(3)

The most well understood of these three types are the resident killer whales. There are three populations of resident orcas in the northeast pacific; the Alaskan Residents, the Northern Residents, and the Southern Residents. All of these groups live in fairly large pods of usually around 30 individuals. Occasionally the entire Southern Resident Community gets together for a big ol' fashion hootenanny. Seriously, this 85 whale strong "superpod" is as close to a college kegger as any species other than humans get. This is the time when the Southern Residents say hey to friends, hook up with each other, and shout across the room to orcas they know. That last one is only partly a joke. Resident orcas are the chatty Kathy's of the ecotypes. They're highly vocal because their favored prey requires them to be highly coordinated in their hunting.

Resident orcas eat nothing but fish, and about 90% of that fishy diet is salmon. Why? Because salmon meat is just drowning in oil. Those natural fats are great for preserving the whales' blubber layer, which keeps them warm. Salmon is also absolutely dense with chemical energy, and that's essential for maintaining an active body and mind. 

All orca ecotypes employ echolocation clicks to navigate their environment. But in order to effectively corral schools of speedy fish, residents employ a complex vocabulary of whistles. Their calls regularly change pitch, tone, and frequency as they communicate with one another. 

"So anyway I said to him" 'go left', and he went right, so I said: 'no, 

your left', and he said: 'What do you mean I'm left? we're all still here'" 

Courtesy: Tundra Ice via Flickr  

Resident oracs are usually the ecotype that people are most familiar with. This is mostly due to the fact the they remain in a relatively small area throughout their lives. The Southern Residents are probably the most extensively studied and photographed whales in the world. They have legions of fans, and what's not to love about residents. They're rarely far away when you need them, they're gregarious, and they eat food that we don't find particularly cuddly. Transient orcas, also called Bigg's killer whales, are an entirely different story.

Transients are the leather jacket wearing, smoking behind the gym, switchblade carrying, greasers of the ecotypes. Everyone who's ever loved a bad boy or girl can get into the transient orcas. "What makes transients the badasses of the dolphins?" I'm glad you asked.

 Courtesy: Poorly Drawn Lines

Transient orcas are primarily mammal eaters, and they almost never touch fish. This ecotype preys upon seals, dolphins, porpoises, occasional birds, and even baleen whales! With each prey type comes a different hunting strategy. Seals are usually grabbed from below the surface and quickly killed, but in contrast, sea lions are gradually beaten to death with the tails of each pod member. Then this frequently happens:

Hahaha Okay I admit this at least a little funny.

Yup, they play with their food. Take what your average cat does to a mouse, scale them both up about 1000 times, and you have a Biggs' killer whale playing with a sea lion. But wait! It gets even more intense. Transients hunt the giant cetaceans by drowning them. I'll let the BBC and David Attenborough give you the specifics in the video below

Really intense footage, but absolutely incredible.

Although each attack type has different characteristics, what's consistent is that transients are quiet and work with a small crew. They swim in loosely defined small pods, usually no more than 10 individuals, to increase each whale's share of the prey. And since their prey hears very well, transients go into stealth mode once they've identified a target. Only once they've taken down their meal do they resume vocalizing. 

While all of his mammal killing may seem unpleasant, it actually makes a lot of sense. Since resident orcas are busy eating up all the oily fish in the nearshore, transients need another source of fat. And there's few higher quality fats than the blubber of marine mammals. By consuming different foods transients and residents can live side-by-side with little interaction and no conflict.

So if Bigg's killer whales and residents consume all the energy rich prey in the nearshore then the third ecotype must live somewhere else. 

It's on the shore isn't it? I knew this would come back to pandas.

They're like the orcas of the land!

Courtesy: fortherock via Flickr

The final of the northeast Pacific ecotypes lives in the offshore environment along the edge of the continental shelf. In one of the most creative namings ever, these offshore orcas are called... offshore orcas. Offshore's are the least well understood of the three ecotypes for a number of reasons. The main being, that the open ocean is so much bigger than the inland waters where transients and residents are usually found. It's not surprising that most of the encounters with offshores have occurred off of California where the open ocean abuts the continent.

"California whales they're so incredible. Black tail flukes, 

with blowholes on top"

Courtesy: Matthew Allen via Flickr

Genetic studies have found that offshore orcas are probably most closely related to residents. They're also similar to residents in their behavior and  general diet. Offshores appear to be fish eaters and live in very large pods, sometimes more than 100 whales strong. It's not clear if this is similar to the summer superpod that the southern residents get into once a year, or something else entirely. 

Where residents and offshores differ is in how far they'll travel, and exactly what kind of fish they eat. The same group of offshore orcas have been seen at Dutch Harbor in the Aleutian Islands, and Dana Point in California. That's 4,435km if the pod swam in a straight line, which it almost certainly didn't. In contrast the Southern Resident population only leaves the Salish Sea near Washington and British Columbia on occasion.

Courtesy: Dahlheim et Al. (2008), Marine Mammal Science 24(3)

We don't have a great idea of offshore killer whales' diets, but they seem to be less picky than residents. They've been seen attacking schools of baitfish, and beating blue sharks with their tails. They've also been found beached with salmon and halibut in their stomachs. Another piece of evidence has led some scientists to speculate that sharks are a major component of their diet. 

When offshore orcas wash up on beaches their teeth are frequently worn down almost to the gumline. Even young animals, whose teeth can't have eroded from age, show a lot of wear. Sharks have rough, sand-papery skin that could probably buff an orcas teeth down to the jaw if they eat them all the time. Offshores also have fewer tooth marks on their bodies from scrapping with other orcas, suggesting their teeth aren't very pointy for most of their lives.  

We've barely begun to scratch the surface of offshores' life history even though we've known about them since the 80's. In fact there's so much more to learn about all three ecotypes. Their behaviors and life styles are so different that they might even warrant being considered several species of orca. But for now, killer whales are a single group of highly intelligent, adaptable, long-lived, nomadic hunters, just like humans before agriculture and urbanization. Killer whales, they're like the humans of the sea!

Several ton, fish-eating, flippered, black and white, humans.

Courtesy: Putneypics via Flickr

References:

Dahlheim, Shulman-Janiger, Black, Ternullio, Ellefrit, & Balcomb, (2008) "Eastern Temperate North Pacific Offshore Killer Whales (Orcinus orca): Occurence, Movements, and Insights into Feeding Ecology", Marine Mammal Science 24(3): 719-729, doi: 10.1111/j.1748-7692.2008.00206.x

Accessed via: http://www.orcanetwork.org/nathist/offshoresdalheim.pdf

Dahlheim & White, (2010) "Ecological Aspects of Transient Killer Whales (Orcinus orca) as Predatorsin Southeastern Alaska", Wildlife Biology 16:308-322, doi: 10.2981/09-075

Accessed via: http://www.orcanetwork.org/nathist/Dahlheim2010.pdf

Ford MJ, Hempelmann J, Hanson MB, Ayers KL, Baird RW, Emmons CK, et Al., (2015) "Estimation of a Killer Whale (Orcinus orca) Population's Diet Using Sequencing of DNA from Feces", PLoS ONE, 11(1): e0144956, doi:10.1371/journal.pone.0144956

Accessed via: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0144956

Riesch & Deecke, (2011), "Whistle Communication in Mammal-eating Killer Whales (Orcinus orca): Further Evidence for Acoustic Divergence Between Ecotypes". Behavioral Ecology sociobiology, 65: 1377-1387, doi: 10.1007/s00265-011-1148-8

"About Killer Whales", Center for Whale Research 

Accessed via: http://www.whaleresearch.com/#!about-orcas/c1qa8

 

Celebrating Sculpin Speciation

Merry Christmas everyone! Since you all have been good little nerds and scientists this year you get a brand new blog post in your stocking. Not only is it our first post in a while, but I'm excited to introduce you to our first ever guest writer.

Brian Harmon (Harmonus fishnerdii)

Brian is currently pursuing the glamorous world of graduate studies at the University of Nebraska. He's a sarcasm enthusiast and passionate advocate for (less than) charismatic (usually micro) fauna. So with out further ado let's get this post started!

Some fish are delicious, others put up a heck'uva fight, a few are particularly weird, aesthetically pleasing, or a critical keystone species. Then there are freshwater sculpins. These cryptic fish pretty much just sit on the bottom, doing nothing. All the time. If they don't swim they just sink, I mean c'mon, even we hydrodynamically challenged humans float. 

A sculpin taking a break from a hard day of... sitting on a different rock.

A true trophy of a sculpin is about 110mm (that's like 4 inches for those who deny the superiority of the metric system) so sculpins don't exactly attract much of a following from the fishing or environmentalist crowds. Actually they don't really have any following, except for a couple of fish nerds here and there. And yet, despite rarely being seen, they are all over North America and Europe, even in super remote and highly polluted waters.

A good day's haul of trophy sculpins.

Now that I have lowered the expectations for this month's Depth and Taxa, it's time to explain why sculpins are an amazing group of fish to study. 

The majestic sculpin. 

Courtesy and permission of Jason Ching

Sculpins present one of those philosophically challenging dinner-table appropriate conversations (especially since you don't want to eat them): what exactly is a species? Now, we drop species names all the time. Even here in this blog, scientific names get thrown around like it's no big deal. Yet it turns out the first man responsible for our modern definition and naming of species, Carl Linnaeus, had it pretty easy. When you have to start at square one, you pick the obvious animals. And it turns out telling the difference between an elephant and a rhinoceros isn't too difficult. And even this guy ran into all kinds of trouble. 

The Hamburg Hydra: one of many "species" Linnaeus debunked 
Courtesy: wikipedia Commons

So let's use a non-aquatic example most people are familiar with: lions and tigers. And a hypothesis: species cannot produce offspring with one another. Except clearly delineated species like lions and tigers can produce offspring: ligers (and the lesser known tigons). "Okay, okay, but they're sterile" you say. Well not... completely. Ever heard of the litigon? Now ligers and litigons are a bit of an odd example because tigers and lions don't meet in the wild.

"Ligers, and tigons, and pizzly bears, oh my!"
Courtesy: Wikipedia Commons

Well here is where freshwater sculpins come back into the story. Freshwater sculpins are notoriously difficult to tell apart unless you like counting fin rays and chin pores under a microscope. And if you're a sane human-being, you don't. 

No, please, you id this one.

Sculpins also don't move much. Which means isolated pockets of different species can be found within the same, rather small river system. Often these pockets overlap. Thus biologists face a challenging puzzle: how do we separate species that look nearly identical and whose ranges overlap?

Modern DNA analysis has gone a long way to solving that problem, while at the same time providing new challenges. For example, the cleverly named and ubiquitous slimy sculpin (Cottus cognatus) seems to coexist with just about every other sculpin species. However, recently biologists discovered the slimy sculpin is not one species but multiple, unidentified species. One newly identified group of previously "slimy" sculpins has been renamed the cedar sculpin (Cottus schitsuumsh). Just try pronouncing that. (Or go here to learn how). Oh and here is the kicker. They live in the same places as slimy sculpins.

A range map for slimy sculpins. Cedar sculpins are limited to western Montana,
 an area also occupied by slimy sculpins
Courtesy: The state of Montana

And they may hybridize with slimy sculpins, producing hybrids that can breed again. Further adding to this confusion is that one of the many species that coexists with slimy and cedar sculpins, the mottled sculpin (C. bairdi) is actually the Rocky Mountain sculpin (C.bondi) because the long-described mottled sculpin doesn't exist in Montana. So just how many species (and which?!) are we talking about?

So.. wait a minute. what defines a species? Well we will add one more group of fish into the mix. Rift Valley African Cichlids (sick-lids) to help explain. A single species of cichlids first colonized Lake Victoria about 10,000 years ago. Within that geologically tiny amount of time, hundreds of species... well... speciated. Many of these species are more closely related to one another than humans are to each other, and yet we are one species, while they are many. Turns out many of their behaviors and visual differences exist specifically to identify exactly who they should mate with. Side note: wouldn't that be nice? 

One of many, many, cichlid species
Courtesy: Wikipedia commons.

Humans introduced the Nile perch (Lates niloticus) into Lake Victoria for food. The introduction of a novel predator drove many of the cichlids to extinction. Many of those left began hybridizing due to changes in population numbers and environmental conditions caused by the Nile perch. Those hybrids continue to propagate, creating, you guessed it, the begins of new species.

A Nile perch. Fun fact: Linnaeus described it, and lions, and tigers. 
Courtesy: Wikipedia commons.

So I leave you with the ever-infuriating question of what exactly constitutes a species? Is it a specific level of genetic difference, producing only sterile hybrids, not producing hybrids very often? Or is the concept of a species a messy continuum that we humans have tried to neatly categorize? Though we can be fairly certain sculpins and elephants are not the same species, we can't figure out how many sculpin species we are talking about.

The closest thing I could find to an elephant-sculpin hybrid. 
Trust me, I looked far too hard.
Courtesy: Wikipedia commons.

It turns out, scientists argue about what is or is not a species all the time. Whether a population of fish is a different species often depends on whether you are a lumper or a splitter. And here's why it matters. Conserving species for the future is a challenging proposition full of trade-offs and hard choices. If we want to save species for future generations, what do we do when we aren't even really sure what the definition for species is? Think it over, and when this dilemma starts to get too hard, go id some sculpins. Maybe start here for a free guide on some more aesthetically pleasing marine sculpins!

Your first challenge.

Thanks once again to Brian Harmon for breaking the seal on guest posts here at Depth and Taxa. If you're an aspiring scientist or educator and you'd like to be featured on this blog contact our editor at patrick@nwnhc.com.

References:

Columbia Slimy Sculpin — Cottus cognatus. Montana Field Guide. Montana Natural Heritage Program and Montana Fish, Wildlife and Parks. Accessed via: http://FieldGuide.mt.gov/speciesDetail.aspx?elcode=AFC4E02080. Last accessed: 12/14/15.

Goldschmidt, T. 1996. Darwin's dreampond. The MIT Press.

USDA Forest Service, news release. Accessed via: http://www.fs.fed.us/rmrs/news/releases/content/?id=14-01-29. Last accessed: 11/15/2015.



Rocky Mountain Sculpin — Cottus bondi. Montana Field Guide. Montana Natural Heritage Program and Montana Fish, Wildlife and Parks. Accessed via: http://FieldGuide.mt.gov/speciesDetail.aspx?elcode=AFC4E02380. Last accessed: 11/15/2015

Gene You're Positively Glowing!

Out on the beaches of the Pacific is a group of heroes. A squad of jiggly life savers, spending their days scanning the surf, waiting for their moment to pull you back from oblivion... 

What!? Oh God...NO. Get your head out of the gutter, uck! What the heck is wrong with you? I'm talking about jellyfish; specifically the water jelly (Aequorea victoria), they're also called crystal jellies and have many other common names, so for this post we'll just call them Aequorea (pronounced: ay-core-ee-uh). 

Just as much acting talent in this photo, as in the one above it.

Courtesy: Denise Allen via Flickr

Now we've often declared our love for jellies. In fact this isn't the first time they've appeared on Depth and Taxa. If you want to get a refresher on the jelly life cycle, and learn about one of Aequorea's cousins check out the older post here. But Aequorea are especially interesting thanks to their contributions to the field of medicine. You might be picturing some kind of Doogie Howser scenario with a jelly subbing in for Neil Patrick Harris, and you'd be right to want to watch that. But what Aequorea have provided for humanity goes beyond just caring for sick individuals, and making us laugh Tuesdays at eight on ABC.

At first glance Aequorea only possess a simple elegance. They're completely clear, and don't have particularly flashy innards like some species. The wagon wheel-like structure inside their umbrellas is a system of canals that distribute nutrients around the jellies' bodies. But radial canals are a basic part of jelly structure, so although they're pretty, they aren't particularly distinctive. To see what has made Aequorea so important to humanity we need to take the lights down.

Oh man, those damn ravers keep leaving their trash everywhere...

Courtesy: William Ward via The Encyclopedia of Life

That ring is the outline of the bell margin of an Aequorea jelly. The glow you see is naturally produced by the jelly itself. Interestingly, we don't know for sure why these jellies produce this light. They don't constantly flash like fireflies, nor do they glow continuously like the stage at a Deadmau5 show. For the most part we've only observed Aequorea glow after they've been jostled by a human. Even if we don't understand why Aequorea glow, scientists have spent a lot of time figuring out how they do it.

In the 1960's, while trying to isolate the glowing material from Aequorea jellies, Dr. Osamu Shimomura and his team determined that a pair of proteins is actually responsible for producing this jelly's light. The first in this dynamic duo is a molecule called aequorin. Aequorin emits blue light when it's exposed to calcium ions. The second protein, which produces that green fluorescent glow we see is called... green fluorescent protein. Points for clarity I guess. Green fluorescent protein, or GFP, only glows when exposed to light in the same spectrum as the light produced by aequorin. So first, calcium ions flow into the aequorin which flashes blue, then the blue light hits the GFP which absorbs it, and then the GFP releases some of the energy it absorbed as green light.

Okay so how is glowing protein helpful to medicine? Well it's what triggers the glow in these proteins that's important. See calcium is an important trigger in both the nervous and muscular system. Calcium ions flowing into nerves spark them to send out the chemicals that transmit information between themselves and the next nerve in the chain. Scientists can inject aequorin into the area around a nerve and figure out where and when the calcium is flowing to the cell by seeing when the aequorin glows! This is incredibly useful when studying nervous systems because you can actually observe a nerve functioning, which is normally an invisible process.

Aequorin being activated by a calcium solution.

So aequorin is pretty cool, but it's green fluorescent protein that has really changed the landscape of cell research. GFP normally absorbs the light from aequorin to glow, but will also absorb light from the nearby UV spectrum. So that same black-light you used to make that Bob Marley poster look so cool in your dorm can be used to peer into the chemicals that sustain life itself.

Scientists managed to clone the green fluorescent protein and ever since have been attaching it to other proteins to watch how they're made, where they go, and how long they last inside the bodies of different animals. Dozens of fluorescent proteins, in several colors, have been created from GFP and others have been found in animals like sea anemones. Mice have been genetically modified with GFP tagged normal cells and glowing red protein tagged cancer cells. When observed under black-light scientists can actually watch how the cancer cells grow and spread in real time without harming the mice.

The thing that makes GFP so powerful is that it can be added to almost any cell or protein. So if you have a question about how fetuses develop, tag an egg cell with GFP and watch it divide. If you want to watch nerves grow as a mouse learns, tag their brains with GFP, and see them think. If you want to release a bunch of infertile male mosquitoes into a population to eliminate malaria without pesticides. Tag their testicles with GFP so you can sort the boys from the girls, and get to sterilizing. All of these things have actually been done using modern genetic techniques and a variety of fluorescent proteins.

These are the nerve cells in a mouse's brain expressing different chemical signals.

You're observing this animal's brain tell its body how to function

Courtesy: ZEISS Microscopy via Flickr 

Okay so maybe it isn't Aequorea itself that'll save your life. Mostly they'll keep eating plankton and washing up on shore like they've been doing for millions of years. But if it weren't for Aequorea's development of GFP we would probably never have been able to discover all that we have about living things, especially our own bodies. Animals and plants shouldn't be protected and preserved solely for their potential usefulness, but if one of the least noteworthy jellies can single tentacledly spark an entire research industry; imagine what else we can learn from the "nobodies" on the tree of life.

References:

Nikon's Microscopy U,
Accessed via: http://www.microscopyu.com/articles/livecellimaging/fpintro.html

The GFP Site; From professor Marc Zimmer at Connecticut College.

Accessed via: http://www.conncoll.edu/ccacad/zimmer/GFP-ww/GFP-1.htm

Mills, C.E. 1999-present. Bioluminescence of Aequorea, a hydromedusa. Electronic internet document available at http://faculty.washington.edu/cemills/Aequorea.html. Published by the author, web page established June 1999, last updated January 11th 2009

Shimomura, O., "The Discovery of Aerquorin and Green Fluorescent Protein", Journal of Microscopy, Vol. 217 Pt. 1, Jan. 2005, pg. 3-15.

Accessed via: http://www.cooperlab.wustl.edu/PracticalAdvice/Shimomura2005.pdf

Naut Again

Oh wow, there's some wonderful news that's come out of the US East coast recently that hasn't gotten the coverage it deser....

"NAUT SO FAST PUNK!"

Courtesy: DarTar via Wikimedia Commmons

Oh, god no, not this again. How many weeks am I going to have to go without getting interrupted by a cephalopod? What do you want chambered nautilus (Nautilus pompilius), and did you seriously just use your own name as a pun?

"I'll use my name however I want after you and that wannabe 

Greek hero besmirched it. She should be proud to be 

associated with us nautiluses."

Courtesy: Michael Bentley via Flickr

Alright, alright, I didn't mean to offend anyone. I wrote about argonauts last week since they're a cool family in their own right. I guess I didn't think about how little people know about your family too. Tell you what, I'll make this post all about you, if you promise to tell the other cephs to stop interrupting me. I don't want a ram's horn squid butting in next week.

"Alright deal, but I'm gonna stand here and make sure you do us justice"
Courtesy: OCVA via Flickr

Okay well, if we're gonna give this family the credit it deserves we need to talk about world domination. Don't worry, you needn't imagine a future where shelled overlords subjugate earth's other species, because it already happened. Nautiluses are old, very old, in fact their family members are the OG cephalopods. The first nautiluses to appear had straight shells, but around 400 million years ago they developed the familiar spiral we see today. They were so successful that they, and their cousins the ammonites, would go on to dominate the seas for eons. Nautilus even survived the worst extinction of all time which killed 96% of all life in the sea. Not too shabby for an animal that's essentially a fancy snail.

Even though they ruled the oceans for so long, the nautiluses eventually gave up their family's dynasty to live a life of quiet retirement. Today only two genera of nautilus exist, down from the 75 or so at their peak. Modern nautiluses are found only in the Indian and Pacific oceans in the deep waters at the steep edges of coral reefs. Yet they are some of the most fascinating organisms to occupy those spaces.

Of course what stands out most about nautilus is their incredible shells. Nautilus are the only cephalopod left to still have an exterior shell, which means they don't need all the gaudy color and texture changing flashiness of their cousins. Instead of hiding, speeding away, or out-thinking their predators nautilus prefer the simple life scavenging food off the bottom; and cruising through deeper water at times when predators are at rest.

They're kind of like that friend from college who moves to
 Idaho and starts a goat farm because "It's just easier."
Courtesy: Hans Hillewaert via Wikimedia Commons



Now you might notice that the nautilus' shell is pretty burly. There are hardly any animals with shells that thick that even bother swimming. Other heavily shelled mollusks like clams and snails spend most of their time on or in the ground. So what does the nautilus do that makes it able to hover up in the water like that? Are they just incredibly strong? Not really. When you watch a nautilus puff along by forcing water through its siphon, it kind of makes you want to hand it an inhaler and tell it to go sit on the bleachers. So if it's not pure herculean strength that keeps the nautilus afloat what is it? Well my friends, the nautilus succeeds thanks to the magic of good engineering.

I think like a third of our readers just found their spirit animal
Courtesy: Jason Westley Upton via Flickr

Inside the shell are the structures that put the "chambered" in chambered nautilus. The largest chamber is where the nautilus' mantle is housed, but the others are empty of everything except air and a little bit of water. When a new chamber forms the nautilus walls its previous space off and amazingly, drains the water. See if the chambers stayed filled then the nautilus would get dragged to the bottom thanks to the weight of the water inside the shell. Emptying water from the chambers has the same effect as if the nautilus were to tie balloons to its shell. The air inside pushes up towards the surface while the weight of the shell pulls down, and the two forces balance one another out to make the nautilus neither sink nor float.

You might be wondering: If the nautilus seals the chambers how does it get the water out? Well running through the chambers is a really cool organ with a really cool name, a siphuncle (pronounced: sigh-fun-kull). The siphuncle is a tube that uses water's own physical properties to fill and empty the chambers. See water has a tendency to try and balance the concentrations of different minerals dissolved in itself. So if you put a screen that will only let water through between two solutions and you make one much saltier than the other; the water will cross the screen to the salty side until the two sides' ratios of salt to water are equal. This is exactly what the siphuncle does. When the nautilus wants to remove water from the chambers it adds salt ions to the outer layer of the siphuncle and the water just seeps on out of the chamber. When the nautilus wants to add water to the chambers it does the opposite. This system requires basically no energy on the animal's part, so it's a great strategy for staying properly buoyant.

Who says functional machines can't be pretty? Those little struts in the center 
of each chamber hold the siphuncle in place as it runs through the shell.
Courtesy: Jitze Couperus via Flickr

Of course everyone focuses on the shell of the nautilus, so much so that these animals are being impacted by fisher people catching them for their shells. Many scientists and citizens who care a lot about nautilus are doing everything they can to show the international community that nautilus, not only deserve, but need our protection. The easiest way to do your part is to never buy new nautilus shells. Instead look around antique stores, or purchase nautilus fossils, which have the benefit of being infused with beautiful minerals from fossilization.

Aside from their shells, nautilus are also impressive thanks to over 90 tentacles! These tentacles are much simpler than the complex arms of the nautilus' cousins. They have no suckers and instead use a series of grooves to grip surfaces. They're also incredibly sensitive to scent/taste. As a scavenger nautiluses need to be very aware of where food is sitting, and all of those tentacles act like an array of antennas picking up the fishy signal of food rotting on the bottom.

Okay nautilus, was that a satisfying amount of information for you? We can always come back another week and learn more.

"Well that was better than naut. It'll do for now, and naut to worry,
you've naut seen the last of me."
Courtesy: David Remsen via Flickr

Ugh, the puns man, the puns...

References:

Dunstan, A., Ward, P., & Marshall, N., "Vertical Distribution and Migration Patterns of Nautilus pompilius", PLoS ONE 6(2): 16311, Feb. 2011.
Accessed via: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0016311

Ward, Peter, "Cameral Liquid in Nautilus and Ammonites", Paleobiology, 5(1), 1979, pg. 40-49.
Accessed via: http://www.jstor.org.ezproxy.library.wwu.edu/stable/2400389?seq=1#page_scan_tab_contents

Crook, R., & Basil, J., "A Biphasic Memory Curve in the Chambered Nautilus, Nautilus pompilius L. (Cephalopoda: Nautiloidea)", Journal of Experimental Biology, June 15th 2008.
Accessed via: http://jeb.biologists.org/content/211/12/1992.long

Dunstan et al., "Nautilus pompilius Life History and Demographics at the Osprey Reef Seamount, Coral Sea, Australia" PLoS ONE, 6(2): e16312, Feb. 2011.
Accessed via: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0016312

Precious Argo

How's the old saying go? "If it looks like a duck, swims like a duck, and quacks like a duck, then it's probably a duck."

"Quack?"

Courtesy: Derek Bruff via Flickr

By extension I can imagine this test applies to any animal. Let's pick a random one and try it, shall we? If it looks like a..... Nautilus, swims like a nautilus, and has a shell like a nautilus it must be a nautilus. 

"Oh my God! What did you just call me!?"

Courtesy: Michael Vecchione via TOLWeb.org

Oh yeah I'm sorry, paper nauti..... I mean greater argonaut (Argonauta argo). I totally forgot about you. How about I make the rest of this post about how awesome you, and the other three species in your family, are to make up for it?

"We can live with that. I'll just sit here and make sure you

 don't mess up again"

Courtesy: NOAA Photo Library via Flickr

Okay where to start? Well, how about at the very beginning like my nanny used to say. Disclaimer: My nanny may have just been Julie Andrews movies. Anyway, we've known about argonauts for an incredibly long time. Their delicate, paper-thin, shells have been found painted on artifacts from 4000 years ago! Of course, back then we barely knew anything about these animals because we were mostly finding their old shells washed up on the beach. 

However many of the ancient Greeks were talented naturalists, and they started looking closer at these coiled beauties. Aristotle noticed that the argonauts could climb out of their shells because they aren't attached to them like a true nautilus or any other shelled mollusk. So how did Aristotle think argonauts got their shell? Well he assumed they stole it. For the longest time scientists thought that argonauts couldn't be making their own shells, so they were taking them from an unknown animal and using them as boats. Now this seems a little crazy, but add in the fact that female argonauts have sail-like webs on two of their arms, and you have the perfect animal to send after the golden fleece. 

Hahaha...What is it even...? Hahaha...There's a boat to compare it to..Hahahaha!

Bless you for this: Gerard Van der Leun, via Flickr

Although the theory that argonauts combined Grand Theft Auto and that pirate Assassin's Creed (Hold on I have to go pitch an idea to Microsoft) persisted well into the 1800's, eventually science started to sober up. We later discovered that female argonauts make the shells using glands in their webs that secret calcite. They spread these webs out over the shell and lay down material bit-by-bit like nature's 3D printer. 

 On the left you can see the webs with chromatophores, extended over the shell.

On the right this female has pulled the webs back, exposing her construction.

Courtesy: Michael Vecchione via TOLWeb.org

 If you're an astute reader, you've probably noticed that I've only mentioned female argonauts so far. This follows the history of these animals because for the longest time we had no idea what the males looked like. Why? You might ask, well they're tiny, like really tiny, only 1% the size of a female, and the biggest species' female only gets to 30cm across. Plus the males don't build shells, oh and sometimes they only have seven arms.

See argonauts are octopuses, and they normally have eight arms like any of their relatives. However one of a male octopuses arms is very different from the others. The third arm on his right side is called a hectocotylus (pronounced: heck-toe-cot-oh-luss) and it's used for reproduction. The males of most bottom-dwelling octopuses insert their hectocotylus into the female's gill opening; and sit there for a bit while a packet of sperm passes from inside his body, down the arm, and into the female's oviduct. Argonauts don't have the luxury of that kind of time though. They differ from their cousins by living up in the water column, instead of down on the sand. Living in the open ocean is great way of avoiding competition with your cousins down below, but it also means you have to travel far and quick to find food, mates, and shelter. 

Because the ocean is so big, and argonauts so small, males may not have many chances to find a female. To make sure they mate effectively the male argonaut's hectocotylus actually breaks off inside the female's body cavity, and he swims away. By embedding his sperm delivery system in the female, the male has insured that it's his DNA that fertilizes the eggs. Plus it's a great way to screw with naturalists. This is not a joke, the scientist who first found a hectocotylus buried in a female argonaut thought it was a parasitic worm!

 Plus what the hell do we call this thing, a septopus?

The eighth arm is kept inside that pouch.

Courtesy: Edwald Rubsamen via Wikimedia Commons and Public Domain

Now here's where the functional beauty of the female's shell can accompany its aesthetic beauty. Since she lives up in the water there's very little to attach her eggs to, and good material could be floating hundreds of miles from the female argonaut, so she lays her eggs right inside the shell. Female argonauts handcraft baby strollers to push their kids around in until they hatch. Not only that, but the shape of the shell allows the female to trap air in its top which helps counter-act the weight of her body and the eggs; and keeps her from rising or sinking too fast. 

You can see the eggs hanging out of the lower part of this female's shell.

She's new to this whole arts and crafts thing.

Courtesy: Bernd Hoffman via Wikimedia Commons

So how'd I do argonaut? Did we cover everything that makes you so cool? Be fair, we don't know much about you since you're all so small and you live in oceans around the entire world.

Whoooo! Nice work! Go team Argo! High eights all around!

Courtesy A.E Verrill via Wikimedia Commons and Public Domain

References:

Finn, Julian K., "Taxonomy and Biology of the Argonauts (Cephalopoda: Argonautidae) with Particular Reference to Australian Material", Molluscan Research, 2013, Vol. 33, No. 3, 143-222.

Heeger, T., Piatowski U., & Moller, H., "Predation on Jellyfish by the Cephalopod Argonauta argo", Marine ecology Progress Series, Vol. 88, 293-296, 1992.

Orenstein, Marcie, "Marine Invertebrates of Bermuda: Paper Nautilus (Argonauta argo)", The Cephalopod Page, 

Accessed via: http://www.thecephalopodpage.org/MarineInvertebrateZoology/Argonautaargo.html 

Mangold, K., Vecchione, M., & Young, R., "Argonautidae", Tree of Life Project, 

Accessed via: http://tolweb.org/Argonauta