Connecting the oceans to land are numerous carbon highways.  These conduits bring food from land to the ocean, supporting an abundance of life.  Our group explores these carbon chains and explores some potential methods of carbon delivery to the deep.  Thus, alligators on the abyss.

At first it may seem fanciful that an alligator carcass might find its way to the deep.  However, dozens of species of alligators and crocodiles are found across the globe, in high numbers, and often in coastal areas.  Through either their normal migrating or foraging activities, or during flooding events, individuals may be found offshore in the ocean.  If one of those individuals meets an unfortunate end, it may fall to the seafloor.

In prehistoric times, the impact to the deep oceans could have been even larger, as large reptiles such as ichthyosaurs and plesiosaurs dominated the sea. Deploying a reptile in the deep sea today may reveal the animals that specialized on the carcasses of long-extinct ancient emperors of the sea.

Earlier this year, our research group placed three alligator carcasses 1.5 miles deep on the seafloor of the Gulf of Mexico in the first-ever alligator fall experiment.  Each of the three alligators met a different fate.

The first alligator had been on the bottom of the ocean for less than 24 hours. Despite the tough hide of the alligator, scavengers quickly got through and began to gorge themselves on the flesh of the alligator. Football-sized animals called giant isopods, relatives of rolly pollys or pillbugs, penetrated the hide in this short time-frame.  This demonstrates the speed and precision with which deep-sea scavengers can utilize any carbon source, even food from land and freshwater systems.

A little over 60 miles to the east of the first alligator, the second alligator had been sitting on the seafloor for a little over a month and a half.  All the soft tissue of the alligator had been removed by scavengers.  A small animal called an amphipod was still darting around looking for scraps, but the only thing that remained was a skeleton.  All of the soft tissue had been consumed. The spine curved just as it had been left.  A depression in the sediments indicated where the full body once laid.  The skull was turned over, likely by scavengers while picking at the flesh on the skull.

A fuzzy carpet covering the bones of the second alligator represented a brand-new species, previously unknown to science.  These zombie worms, or Osedax, colonize the bones of many types of vertebrates and consume the lipids within.  This was the first time zombie worms had ever been observed in the Gulf of Mexico or from an alligator fall.  They also demonstrate yet another pathway in which carbon from land makes its way into deep-sea food webs.

Another 60 miles east lay the third alligator.  It had only been eight days since it was laid on the seafloor.  As the camera panned to the marking device, a floating bucket lid attached to a rope like an underwater flag, it became clear that the alligator was missing.  All that remained where it had been dropped was an alligator-shaped depression in the sediments.  Drag marks in the sediment paved a path to what remained of the alligator fall.  An animal dragged this alligator 30 feet and left only the 45-pound weight and rope.  The rope had been bitten completely through. To consume an alligator, and create this disturbance, the animal must have been of great size.  We hypothesize that most likely a large shark, like a Greenland shark or sixgill shark, consumed this alligator whole.

Three alligator falls in the abyss met three very different ends, from being consumed by football-sized cousins of rolly polys, to zombie worms eating their bones, to a large shark dragging it away and consuming it whole.  This research has given us a glimpse into what impact large reptiles had in past oceans, as well as the role they play today.  It is clear that deep-ocean scavengers have no qualms about successfully and quickly consuming food that originated on land or freshwater.

Read more about this research in our group’s recent publication in PLOS One: “Alligators in the abyss: The first experimental reptilian food fall in the deep ocean.”

The post Alligators in the Abyss: Part 2 first appeared on Deep Sea News.

Wait…what? What kind of mad science is this?

What you need to know is that the deep oceans, encompassing depths below 200 m, cover most of Earth and are especially food-deprived systems. Primary production of carbon is minimal only occurring through alternative pathways such as chemosynthesis. However, chemosynthesis is a tiny fraction of total ocean production (0.02–0.03%) and the energy that sustains most deep-sea organisms is sequestered in sinking particulate organic carbon derived from plankton hundreds of meters to kilometers above near the sea surface. At the abyssal seafloor, this sinking particulate organic carbon represents less than 1% of surface production.

This minimal amount of carbon available opens the door for more unique sources of carbon. Enter food falls and aligators.

The remains of large plants, algae, and animals arrive as bulk parcels that create areas of intense food enrichment. Deep-sea scientists have explored these food falls through both naturally occurring and experimentally deployed wood (#woodfall) and plant remains, cameras baited with animal carcasses, chance occurrences of and deployed intact whale carcasses several miles deep on the seafloor. These experimental and natural food falls have revealed the important role they play in deep-sea diversity. Many of these large food falls on the deep-sea floor, host highly diverse and endemic suites of organisms in kind of food island. In addition, food falls may represent significant transport highways of carbon into the deep oceans. For example, during Typhoon Morakot, wood was estimated to carry a total of 4*10¹² g of organic carbon into the oceans, nearly 25% of the total annual riverine discharge of organic carbon in the same region. On the deep-sea floor, a single wood fall can enrich sedimentary organic carbon by >25% even after several years.

But why alligators? With regard to animal falls, prior work as focused primarily on whales and other cetaceans, pinnipeds, large fish such as tuna, and elasmobranchs. However, it very likely that marine reptiles both currently, and even prehistorically, are an important source of carbon in the deep oceans. Before the existence of whales, perhaps large marine reptiles like ichthyosaurs, mosasaurs, and plesiosaurs hosted diverse and endemic invertebrate communities on sunken carcasses, similar to modern-day whale falls, and contributed significantly to the deep-sea carbon budget. From ichthyosaur and plesiosaur remains, there is evidence of molluscs that are also associated with Eocene seeps. A fossilized limpets are also found in close association with the bones of a fossil leatherback turtle from the Middle Eocene. In the modern oceans, carcasses of Alligator mississippiensis serve as the closest modern analog of ichthyosaur, mosasaur, plesiosaur food falls.

Alligator carcasses in the deep ocean are also not as nearly impossible as you might think.  Both live individuals and carcasses of alligators are frequent on beaches and in coastal surf.  A 3-meter individual came ashore at Folly Beach, South Carolina in 2014 and in 2016 a carcass of a 4-meter individual washed up on a beach in Galveston, Texas.  These individuals of A. mississippiensis may be easily carried offshore by major rivers or during large storm events, tropical storms, and hurricanes.  Live A. mississippiensis have been observed 30 kilometers offshore and after Hurricane Katrina in 2005, an alligator was found 25 kilometers offshore. During the 2011 Mississippi flood event, several dead alligators were observed in the mouth of Atchafalaya River.

Thus, I am on ship, 100’s of kilometers from shore, placing an alligator 2 kilometers deep on the seafloor.

*The three alligators were culled by the state of Louisiana to control population numbers and in aid of restoration efforts. The alligator carcasses were then permitted to us for scientific use. The conservation and any taking of alligators in Louisiana is a very serious and thorough process. You can read more about the conservation success story that is alligators in Louisiana here https://t.co/LQskiPyg6e.

The post Alligators in the Abyss first appeared on Deep Sea News.

The post Experience the Life of the Deep Gulf of Mexico in 20 Videos first appeared on Deep Sea News.

The goal was to create a tree where the top represented the ocean’s surface and the base representing the abyssal floor. With a series of white, blue, and black ribbon and silver and blue miniature bulb ornaments, we created the effect of attenuated light as you move deeper. We wanted to make sure to include both a remotely operated vehicle on a lighted tether as well as lighted bathysphere. The tree also included a giant squid attacking a shark and whale fall complete with crabs and eels. We also made some tiny experimental wood falls to resemble the real ones we now have deployed all over the Gulf of Mexico.

You can print all of these decorations yourself. The complete collection can be found in my Thingiverse collection and include:

• The research vessel on top is the ICE – the icebreaker by vandragon_de (with the addition of little printed A-frame for the aft deck.
• The basic and blocky (or to sound like a sophisticated maker low-poly) remote operated vehicle was designed by us.
• Giant Squid by TheGreenFilament
• Shark! Sliced to Print by MacGyver
• Starfish model by Empiricus
• The Voyage of the Bathysphere by themindseye
• LOW POLY CRAB by RaffoSan (for whale fall)
• Eel by Benc (for whale fall)
• Whale by YahooJAPAN (whale for whale fall)
• Giant Deep-sea Isopod by the one and only Andrew_Thaler. (The model is actually based on a real specimen in our lab.)
• Puffer Fish (of awesomeness) by Dinoman (garland)
• A simple log by Montravont
• Vampire Squid by sinryan
• Hammerhead Shark by pmoews

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The post The Fantastical Beasts of the Deep Gulf of Mexico first appeared on Deep Sea News.

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.

The giant deep-sea jellyfish, Stygiomedusa gigantea

Siphonophore

Blanket Octopus, Tremoctopus sp.

Dumbo Octopus, Grimpoteuthis

Vampire Squid, Vampyroteuthis infernalis

Giant Squid, Architeuthis dux

Swimming sea cucumber, Enypniastes sp.

Giant Ostracod, Gigantocypris sp.

Giant Isopod, Bathynomus giganteus

Polychaete worm, Annelida

The fish with a transparent head, Macropinna microstoma

Deep-Sea Frogfish, Family Antennariidae

Hydrothermal Vent

The post My favorite deep-sea GIFs first appeared on Deep Sea News.

7. Stingray eating a crab

9. Deep-sea crab eating a Giant Isopod

The post Top 10 GIFs of Ocean Animals Eating Other Animals first appeared on Deep Sea News.

There are so many amazing aquatic species out there, it’s practically impossible for any one person to see them all, even if they dedicated their entire life to marine biology research.  To that end, I reckon every good marine bio enthusiast needs a Bucket List of species to strive to see before they die.  I’m being really exclusive here – seeing it dead at a market or live in an aquarium counts to the life list.  I’ve been lucky enough to see some incredible animals, but here’s the ten species I haven’t seen yet and am determined to before I shuffle off this mortal coil:

Thanks to some great experiences, I’ve crossed some off my list (marked through below). Here is my top ten 14 15 (I keep thinking of more).  Unlike Al, I won’t count dead or aquariums encounters.  I do count encounters with submersibles and remotely operated vehicles.  How do I add species to my bucket list?  I use the HS index.  Upon encountering a specific animal, I must anticipate that I will declare HOLY SHIT! THAT WAS AWESOME! You may notice a lack of deep-sea creatures on the list.  I consider myself lucky that I have seen everything from carnivorous sponges, tripod fish, flytrap anemones, to this rare deep-sea anglerfish (I was on the ROV dive that some of the photos were taken on), and the world’s largest single celled organism.  I continue to be awed by both new discovery and encounters with old deep-sea friends.  The list below represents species I would not normally encounter in my main research program.

Think I’m missing something? Add your thoughts and your bucket species on the list below

1. Whale shark-Rhincodon typus  The largest  fish and shark! Yes you will start to note a theme. With my recent excursion to the Afeura to observe the whale shark aggregation, I can cross this one off my list.  With Miriam, I had dove with whale sharks at the Georgia Aquarium, a truly amazing experience. However, this did not compare to being in the open ocean, miles from land, snorkeling with dozens of whale sharks. I’ve already pontificated about the really cool science I conducted involving sharks and lasers (no I can’t make this stuff up), but snorkeling along side a 30 foot long male whale shark is beyond words.

2. Giant Isopod-Bathynomus giganteus The largest isopod! My first dive in a submersible, the Sealink, occurred in the Tongue of the Ocean in the Bahamas.  During that dive, I saw a Giant Isopod for mere seconds before it quickly swam away.  Since then, my contacts have been limited to dead specimens.  I count this as siting but I long for more substantial encounter.

3. Blue Whale-Balaenoptera musculus The largest animal ever to have lived!  I think I may have saw one in Monterey Bay from the superb ocean view of my postdoc advisor’s office (so hard to pay attention during our conversations with a view like that), but I can’t be sure.  I want to dive or snorkel with this massive beast!  I think, and much like it was for whale sharks, you really can’t get a sense for how large an animal until your next to it contemplating your own smallness.

4. Australian Trumpet-Syrinx aruanus The largest snail currently on earth, there were bigger that are now long extinct, can reach lengths of almost 3 feet (~1m) long and a weight of about 40 pounds (18kg)!  It occurs along the northern half of Australia toward Indonesia and PNG.

5. Giant Clam-Tridacna gigas The world’s largest bivalve!  The largest can reach sizes of over 400 pounds and four feet across!  HOLY SHIT THATS BIG!  I’ve seen these in aquariums including the fantastic set of them at the California Academy of Sciences (where I someday hope to work, representatives from there can find my contact info at craigmcclain.com).  However, these are relatively small at about a foot across.  I have also seen shells in museums near their maximum size.  But I really, really, really want to see one in the wild.

6. Giant Squid or Colossal Squid-Architeuthis dux or Mesonychoteuthis hamiltoni Speaking of things I want to see in the wild!  I have seen multiple specimens of giant squid, including the specimen made famous and stolen in the novel by China Mieville.  Unfortunately, I have never seen any part of a colossal squid.  However, even thought the chances of this are extremely rare, I say a prayer at the beginning of every ROV or submersible dive that this will be time.  Of course, this will one also has the largest HS Index.  HOLY SHIT WAS THAT A GIANT SQUID!

7.Lion Mane’s Jellyfish–Cyanea capillata/Cyanea arctica–The world’s largest jellyfish.  The bell can reach a diameter of 7 feet and the tentacules can trail over 100 feet.  Although they occur throughout the world’s oceans the largest specimens occur closer to the Arctic in colder waters.

So not all my marine bucket list are size record holders and some of them overlap with Al’s.

8. Coelacanth-Latimeria spp  How could this not be on the list!
9. Blue Footed Booby-Sula nebouxii The males do a dance to attract the ladies that includes lifting up their blue feet proudly.

10. Scarlet Ibis–Eudocimus ruber Count this one done!  I didn’t even know this should be on my bucket list until I saw them roost in Trindad in person.  The brilliant scarlet coloration is breadth taking and leaves one in awe of its intensity.  Massive flocks gather in wetlands like the Caroni Swamp of Trinidad.

11.  Leafy sea dragon – Phycodurus equus. To date, I’ve only seen them in aquariums. Some scuba diving and trip to New Zealand/Australia in December (as part of the Deep-Sea Biology Symposium) will remedy this!

And like Al I have to include
12. Garden eels –Heteroconger, Gorgasia, Taenioconger
13. Christmas Island red crab – Geocarcoidea natalis
14. Flying squid – Todarodes pacificus

15 And last the Mastigas sp and Aurelia sp of Jellyfish Lake in Palau.  I would snorkel among 1.000’s of jellyfish in these lakes and proclaim HOLY SHIT THAT’S A LOT OF JELLYFISH

The post My Marine Biology Bucket List first appeared on Deep Sea News.

Mobula sp. – devil ray

Sperm whale, Physeter macrocephalus

Flying squid, Todarodes pacificus

Yellowfin tuna, Thunnus albacares

Sailfish, Istiophorus sp.

Manta ray, Manta sp. (Most “manta jumps” on google are actually Mobulas, but this one’s for real)

White shark, Carcharodon carcharias

Emperor or King penguin, Aptenodytes sp.

Mahi mahi, Coryphaena hippurus

Commerson’s dolphin, Cephalorhynchus commersonii

Wahoo, Acanthocybium solandri

Tarpon, Megalops atlanticus

Minke whale, Balaenoptera acutorostrata

And of course, what anthology of jumping marine critters would be complete without the famous leaping giant isopods (Bathynomus giganteus) of Upper Djiboutistan:

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