The post Is Anybody Here a Marine Biologist? first appeared on Deep Sea News.

We’ve all tried this before in a swimming pool or in the ocean, I’m sure: you hold your breath, dive under water, and try to swim as far as you can in an attempt to imitate that killer whale you saw at SeaWorld. After what feels like a life-time, but in all reality is a pitiful 30 seconds of lung-burning agony, you splutter to the surface gasping for oxygen like Newt Gingrich after 10 minutes on a treadmill. You ask yourself, “How on earth does Shamu do that?” The key to how marine mammals manage to hold their breath for so long — for well over an hour in the case of elephant seals and sperm whales — lies largely within their muscles, which are jam-packed full of myoglobin. Myoglobin is haemoglobin’s close relative; and like most close relatives, it’s really good at showing up its inferior relation. It ferociously sucks up and holds onto oxygen, and is also less prone to being damaged by the acidic environment in muscles that follows oxygen-starvation; it is just what a diving sea creature needs. We also have myoglobin in our muscles, but marine mammals can have more than 30 times the amount that we do. As a general rule, the more myoglobin in the muscles of a mammal, the longer it can “hold its breath”.

A group of scientists, led by Scott Mirceta from the University of Liverpool in the UK, have modelled the evolutionary history of myoglobin over the last 200 million years. They show that as marine mammals evolved, not only did the amount of myoglobin in their muscles increase, but that the myoglobin proteins became increasingly charged (less “sticky”), and therefore better able to repel each other, and do their job, whilst still carrying plenty of oxygen to the muscles. The scientists also managed to estimate how much myoglobin was found in the evolutionary ancestors of many marine mammals. The study provides many insights into the evolution of dolphins, whales, seals, and sea lions from terrestrial mammals — resembling you or me gasping for oxygen in a swimming pool — to the slick divers they are today.

The ancestors of modern Paenungulates (a taxa including elephants, manatees and dugongs) were shown to be the first group of land mammals that took to the sea more than 64 million years ago. After making the water their home, increases in body size were a big evolutionary advantage allowing organisms to dive for longer (larger organisms can store more myoglobin and also have lower metabolisms). This is one reason why many marine mammals are so much bigger than their land-dwelling relatives.

One finding which perhaps isn’t too surprising is that the ancestors of today’s whales, dolphins, seals and walruses had low levels of myoglobin when they first ventured into the sea. They would have been pretty damn useless at diving for any sustained period of time and almost certainly foraged for food, and went about their everyday business, in shallow waters. Some creatures, such as the manatees, never really changed; they have low myoglobin concentrations in their muscles to this day and eek out their existence feeding on seagrass in shallow waters. But those organisms that began to pack their muscles with myoglobin were able to dive deeper and longer and, in the process, opened up a whole new world of feeding opportunities for themselves. They evolved from inelegant oxygen-gasping animals feeding near the surface, to highly refined deep-diving marvels of the ocean, capable of holding their breath for up to an hour, or more, and diving hundreds to thousands of metres beneath the surface. All they needed was millions of years of evolution. Unfortunately, you and I don’t have that sort of time. In the absence of a culture of “myoglobin-doping” (don’t laugh, cyclists are already talking about it!), it looks like we will have to make do with our pathetic 30 seconds of underwater suffering the next time we are in the water.

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Accidental swallowing can also occur in the animal kingdom.  During 1979-1981, William Dolphin* and Daniel McSweeny were observing eating behavior of humpback whales in Fredrick Sound, Alaska.  At around 3:30 in the afternoon, one of the humpbacks defecated on the surface.  William and Daniel being great scientists took scat samples.  Among the scat and to no surprise was found numerous exoskeletons of krill, one of the primary food sources of humpbacks besides small fish.  However, two unique items for a humpback diet were also found among the scat.

Also included were the remains of two birds, identified by general size and bill shape as Cassin’s Auklets. Feathers were largely lacking and the eyes were missing but otherwise the epidermis was intact and exhibited only superficial signs of digestion.

The auklets’ stomachs also contained krill.  So how did nature construct this version of turducken (krill inside an auklet inside a humpback, krillhumplet)?  Likely the auklets were accidently ingested by the humpbacks as both the birds and whales were feeding on the krill swarm.  William and Daniel estimates indicate more than 150 whales and 2,500 birds were feeding on the same krill swarm at the time.  As Dolphin and McSweeny end their scientific paper “For the auklets this was simply a case of being in the wrong place at the wrong time.”

Of course this pales in comparison to the checklist of items found in the stomach of tiger sharks.

rubber tire, roll of tar paper, roll of chicken wire, bag of potatoes, sack of coal, rags, paper, aluminum foil, beer bottles, burlap sacs, chicken coop [what?], plastic bags, aluminum soft-drink cans, nails, nuts and bolts, 2-pound (1 kilogram) coil of copper wire, small barrels, old pants, overcoats, raincoat, pair of shoes, boots, empty wallet, bag of money (was this off Jersey?), finger ring, driver’s licence, driftwood, pieces of coal, mass of tangled hair, explosives, brass casing from an 18-pound (8 kilogram) shell, tools, leather, fabrics, boat cushions, unopened tin of salmon, 2-pound (1 kilogram) can of peas, cigarette tin, tom-tom, oral contraceptive dispenser, oceanographic drift marker, steak bone, seeds, nuts, grass, jellyfish, conch shells and opercula, horseshoe crabs, tunicates, head and forequarters of a crocodile [shark vs. crocodile!], chickens, pelicans, seagulls, rats, black cat, spaniel with collar, pigs, pig parts, hind legs of sheep, cattle bones and hooves [including a full head], deer antlers, horse parts [including a full head], donkey parts, hyenas, monkeys, and [rarely] human remains.

The tiger shark is so badass it often consumes landbirds like the Yellow-billed Cuckoo, Bahama Yellowthroat, Morning Dove, and Woodthrushes. These likely represent opportunistic feedings on on unsuccessful bird migration attempts over water.

So what does this tell us?  First, tiger sharks are badass and deserving of spot on the 10 species every man should love list.  Second, humans have done a phenomenal job of polluting the ocean.  Seriously a chicken coop, a tire, and explosive?  Third and most importantly, is the peculiar feeding habits of the  tiger shark perhaps represents a beautiful example of evolutionary adaptation.

Despite the fact that the tropical seas it typically inhabits are rather nutrient-poor, this species grows to impressive size – a length of at least 18 feet (5.5 metres) and a mass of more than 2,000 pounds (900 kilograms). Perhaps as an adaptation to its nutrient-poor habitat, the Tiger Shark seems willing to extend its diet to just about anything it can swallow. As though to protect it from its own gastronomic adventurousness, the Tiger Shark has a capacious stomach with a muscular wall that is proportionately some three times thicker than that of any other [shark].

*real name

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A Texas Tech University whale researcher said she and others found evidence of exposure to polycyclic aromatic hydrocarbons PAHs and persistent organic pollutants, including the pesticide DDT, in Pacific Ocean-dwelling sperm whales.

via Pacific sperm whales exposed to PAHs, pesticides, other pollutants.

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hccreekkeeper writes on his youtube page for this video:

This was the most emotionally disturbing video I have ever done!
A flight over the BP Slick Source where I saw at least 100 Dolphins in the oil, some dying. I also photographed a Sperm Whale covered in oil all around it’s blow hole.
Please spread this around the world. Send me any links to places it gets posted so I can follow.
I want to piss off the world. Who will answer for these gentle creatures?

I for one am seriously pissed off.

Hat tip to Mark Powell at Blogfish.

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“Whales, like any animal or plant on the planet, are made out of a lot of carbon,” he said.

“And when you kill and remove a whale from the ocean, that’s removing carbon from this storage system and possibly sending it into the atmosphere.”

He pointed out that, particularly in the early days of whaling, the animals were a source of lamp oil, which was burned, releasing the carbon directly into the air.

“And this marine system is unique because when whales die [naturally], their bodies sink, so they take that carbon down to the bottom of the ocean.

“If they die where it’s deep enough, it will be [stored] out of the atmosphere perhaps for hundreds of years.”

Pershing’s solution is to offer a trading scheme similar to carbon credit trading. Whaling nations can receive good carbon karma for not whaling or whaling less. I haven’t seen the talk nor read a paper on this so do not feel qualified to opine on this matter. The troubling aspect to me is the general idea sinking things to the deep-sea is a great way to solve problems. Out of sight, out of mind right?

What happens to a whale after it sinks to the seafloor? Let’s review!

Figure 1: Whale Death Cycle. Some images from If Its Hip, Its Here, Craig Smith (U. Hawaii) and MBARI.

But, let a wee bit closer look at those bones, looks like some fuzzy stuff on them.

Figure 2: Osedax, only discovered in 2004, now has more than a dozen species described. Figure from Vrijenhoek et al. 2009 in BMC Biology (open access).

BOO YA!! Bone-eating zombie worms from hell in your eyez!! All your precious carbon, locked away in the forbidden depths of the abyss, still gets recycled. I don’t know how long it takes, but eventually, some point in time, some of that carbon will get released back into shallower waters through gametes broadcast upwards or upwelling of currents. Some will get buried, but in millions of years as the plates shift and subducted, what was once laying on the seafloor will be crushed and melted come out of a volcano. Should we be worried? Probably not, but I bet his calculations don’t take into account release of carbon through decomposition on the seafloor. Not mention that the release of the lipids from whale bone creates a sort of mini-seep around the skeleton which generates methane, another greenhouse gas.

The real problem with whaling is the destruction of this important habitat – the Whale Fall habitat. Every whale removed from the ocean is an ecosystem LOST to a unique and diverse community in the deep sea. A stepping stone connecting disparate populations LOST. A novel metabolic pathway or potential new drug discovery LOST. An important undiscovered species that may hold a key insight into the evolution of its group LOST. In 2009, Japan harvested 680 whales – 680 rare, long-lived, nutrient-recycling ecosystems LOST. Won’t someone think of the poor, little bone-eating worms and all the other unique animals that rely on whale carcasses for their home?

(Hat tip to a crazy drunken Irishmen for the inspiration.)

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