deep sea | Deep Sea News https://deepseanews.com All the news on the Earth's largest environment. Wed, 08 Jan 2020 21:54:00 +0000 en-US hourly 1 https://csrtech.com Alligators in the Abyss: Part 2 https://deepseanews.com/2020/01/alligators-in-the-abyss-part-2/ https://deepseanews.com/2020/01/alligators-in-the-abyss-part-2/#comments Wed, 08 Jan 2020 21:53:59 +0000 https://www.deepseanews.com/?p=59185 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…

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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.

A crocodile swimming in the open sea. Crocodilian species have been utilizing marine habitats more in recent years.

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.

Ancient marine reptiles such as this one dominated prehistoric oceans. Studying alligator falls today may give us insight into what happened when these large predators of the past died and sunk to the seafloor.

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.

Giant isopods made it through the tough hide of the alligator in less than 24 hours. These scavengers opportunistically gorge themselves and then can go years without eating another meal!

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.

The second alligator had been reduced to a skeleton in only a month and a half.

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.

The fuzzy carpet covering the skull is a brand-new species of zombie worms, or Osedax, previously unknown to science!

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.

The third alligator was missing after eight days! The depression shown here was where the carcass had once laid.

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.”

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Slow Road to Recovery after the Deepwater Horizon oil spill for Deep-Sea Communities https://deepseanews.com/2019/10/slow-road-to-recovery-after-the-deepwater-horizon-oil-spill-for-deep-sea-communities/ https://deepseanews.com/2019/10/slow-road-to-recovery-after-the-deepwater-horizon-oil-spill-for-deep-sea-communities/#comments Sun, 20 Oct 2019 03:16:41 +0000 https://www.deepseanews.com/?p=59179 The Deepwater Horizon disaster released approximately 4 million barrels of oil from the Macondo Wellhead over the course of 87 days in 2010.  Thus, becoming…

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The Deepwater Horizon disaster released approximately 4 million barrels of oil from the Macondo Wellhead over the course of 87 days in 2010.  Thus, becoming the largest accidental marine oil spill in history. The impacts of the oil spill were readily visible on shorelines, beaches, and marshes.  

However, in the deep Gulf of Mexico the  devastation was hidden 2 kilometers below in the dark depths of the ocean .  

Investigations of the site began just months after the oil spill using a remote operated vehicle. Dramatic losses of deep-sea biodiversity in the immediate aftermath of the spill were documented by Louisiana State University researchers.  Additional surveys continued for one year until the summer of 2011. Meanwhile, ship-board collection of sesdiments monitored the slow recovery of life, noting a 40-90% reduction in diversity, on the deep-sea floor until 2014

…after which monitoring stopped. 

In 2017, Clifton Nunnally and I with a team of scientists revisited the DWH wreckage and Macondo wellhead site for the first time since monitoring ceased in 2011.  Video captured a deep sea unrecovered after 7 years.  Showing a seafloor, marred by wreckage, physical upheaval and sediments covered in black, oily marine snow unrecognizable from the healthy habitats in the deep Gulf of Mexico.

Near the wreckage and wellhead, many of the animal characteristic of other areas of the deep Gulf of Mexico, including sea cucumbers, Giant Isopods, glass sponges, and whip corals, were absent.  What remained was a homogenous wasteland in contrast to the rich heterogeneity of life seen in healthy deep sea.  

Conspicuously absent were the sessile animals that typically cling to any type of hard structure in an otherwise soft, muddy habitat.  Hard substrate in the deep sea is a valuable commodity but at the Deepwater Horizon site metal and other hard substrates were devoid of typical deep-sea colonizers.

Sea floor communities at the impact site were also characterized by high densities of decapod shrimp and crabs.  Crabs showed clearly visible physical defects and sluggish behavior compared to the healthy crabs outside of the impacted zone of the Deepwater Horizon wellhead.  

We hypothesize these crustaceans are drawn to the site because degrading hydrocarbons may serve as luring sexual hormone mimics. Once these crustaceans reach the site they may become too unhealthy to leave in a La Brea Tarpit scenario.

The scope of impacts may extend beyond the impacted sites with the potential for impacts to pelagic food webs and commercially important species.

Our Recommendations:

  1. Longer funding cycles are needed to assess the recovery of deep-sea ecosystems.
  2. Increased commitment to fund pre-impact baseline surveys.
  3. Stronger, more explicit policy to support future monitoring efforts.

Overall, deep-sea ecosystem health, 7 years post spill, is recovering slowly and lingering effects may be extreme. 

In an ecosystem that measures longevity in centuries and millennia the impact of 4 million barrels of oil constitutes a crisis of epic proportions. 

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The lingering and extreme impacts of the Deepwater Horizon oil spill on the deep sea https://deepseanews.com/2019/09/the-lingering-and-extreme-impacts-of-the-deepwater-horizon-oil-spill-on-the-deep-sea/ Sun, 08 Sep 2019 22:21:09 +0000 https://www.deepseanews.com/?p=59152 From the darkness emerges a boot. An old leather, steel-toed, work boot. It shouldn’t be there resting on the seafloor nearly two kilometers deep. I’m…

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A worker’s boot at nearly 2 kilometers deep.

From the darkness emerges a boot. An old leather, steel-toed, work boot. It shouldn’t be there resting on the seafloor nearly two kilometers deep. I’m speachless. Even knowin this was going to be one of the toughest dives of my career, I’m still not prepared.

Seven years prior in 2010, Marla Valentine and Mark Benfield were the first scientist to visit the deep-sea floor after the Deepwater Horizon accident. On 20 April 2010, and continuing for 87 days, approximately 4 million barrels spilled from the Macondo Wellhead making it the largest accidental marine oil spill in history. Just months after the oil spill, Valentine and Benfield conducted video observations with a remotely operated vehicle (ROV) of the deep-sea impact. Overall, they found a deep-sea floor ravaged by the spill. Much of the diversity was lost and the seafloor littered with the carcasses of pyrosomes, salps, sea cucumbers, sea pens, and glass sponges.

A deep-sea crab crawling along the Deepwater Horizon spill site disturbs oily sediments

Researchers continued to find severe impacts on deep-sea life. The numerical declines were staggering within the first few months; forams (↓80–93%), copepods (↓64%), meiofauna (↓38%), macrofauna (↓54%) and megafauna (↓40%). One year later, the impacts on diversity were still evident and correlated with increases in total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbons (PAH), and barium in deep-sea sediments. In 2014, PAH was still 15.5 and TPH 11.4 times higher in the impact zone versus the non-impact zone, and the impact zones still exhibited depressed diversity. Continued research on corals found the majority of colonies still had not recovered by 2017. However, studies examining the impacts of the DWH oil spill on most deep-sea life ended in 2014.

What should be a seafloor rich with invertebrates is a depauperate seafloor with only crustaceans. Note the discoloring of the sediment

This gap in knowledge on the lingering impacts of one of the largest oil spills of all time is why I sit here in this cold, dark, ROV control room staring at a work boot in the abyss. A year prior, I had reached out to Mark Benfield about replicating his ROV methods and locations. I am here seven years after his study beginning to replicate his first video transect.

Within minutes of reaching the seafloor with the ROV, every scientist on the vessel staring at monitors showing live video from remote seafloor knew something was wrong. As Mark Benfield, Clif Nunnally, and I report in a new open-access article, the deep sea was not recovering at the impact site.  The seafloor was unrecognizable from the healthy habitats in the deep Gulf of Mexico, marred by wreckage, physical upheaval and sediments covered in black, oily marine snow.

Near the wreckage and wellhead, many of the animals characteristic of other areas of the deep Gulf of Mexico, including sea cucumbers, Giant Isopods, glass sponges, and whip corals, were absent.  What we observed was a homogenous wasteland, in great contrast to the rich heterogeneity of life seen in a healthy deep sea.

Conspicuously absent were the sessile animals that typically cling to any type of hard structure in an otherwise soft, muddy habitat.  Hard substrate in the deep sea is a valuable commodity but at the Deepwater Horizon site metal and other hard substrates were devoid of typically deep-sea colonizers.

A riser pipeline on sea floor. What should be a prime real estate for deep-sea life, hard substrates a rarity in soft muds of the deep, is completely void of life.

The seafloor at impact site was characterized by high numbers of shrimps and crabs.  Crabs showed clearly visible physical abnormalities and sluggish behavior compared to the healthy crabs we had observed elsewhere.  We believe these crustaceans are drawn to the site because degrading hydrocarbons serve as luring sexual hormone mimics. Once these crustaceans reach the site they may become too unhealthy to leave much like those prehistoric mammals and the Le Brea tarpits.

One of the many healthy crabs observed at the oil spill site.

The ROV dive began with a boot belonging to one of the workers on the Deepwater Horizon rig. The dive ended at the wellhead, now capped with a memorial to those workers who lost their lives. A dive bookended with reminders of the human tragedy of the oil spill. The narrative that unfolded between these was an environmental catastrophe. In an ecosystem that measures longevity in centuries and millennia the impact of 4 million barrels of oil continues to constitutes a crisis of epic proportions.

The cap on the Macondo wellhead

Valentine, Marla M., and Mark C. Benfield. “Characterization of epibenthic and demersal megafauna at Mississippi Canyon 252 shortly after the Deepwater Horizon Oil Spill.Marine Pollution Bulletin 77.1-2 (2013): 196-209.

McClain, Craig R., Clifton Nunnally, and Mark C. Benfield. “Persistent and substantial impacts of the Deepwater Horizon oil spill on deep-sea megafauna.Royal Society Open Science 6.8 (2019): 191164.

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You are what you eat! Using bad boy carbons to understand food webs https://deepseanews.com/2019/05/you-are-what-you-eat-using-bad-boy-carbons-to-understand-food-webs/ Mon, 20 May 2019 19:44:36 +0000 https://www.deepseanews.com/?p=59099 Remember all the details about the periodic table from high school chemistry?  Yeah, me neither.  Don’t worry – we will get through this together. Let’s…

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Remember all the details about the periodic table from high school chemistry?  Yeah, me neither.  Don’t worry – we will get through this together. Let’s focus on carbon.  Carbon is the building-block of all organic (i.e., living) things, so it’s kind of a big deal. All the other elements are a little bit jealous. Okay, so on the square for carbon in the periodic table, there’s a giant C – for carbon… okay got it.  But there’s all these mysterious numbers around the big C.  WHAT DO THEY MEAN!!!??? SOMEONE PLEASE SEND HELP!!!! I’m remembering why I never really liked Chemistry class……..  Breathing… but seriously, I guess it’s not that hard. The first number is a “6”, and this is its “atomic number.”  It corresponds to how many protons and how many neutrons it has.  You add protons + neutrons to get the “atomic weight” of the element, in this case 12. Okay, this is fine, simple math… but not all carbons follow these rules (UGH).

Carbon as it appears on the periodic table

These bada$$ carbons are “isotopes”, sort of like fraternal twins (or triplets/quadruplets) where one is blazing their own path.  One of the twins is your regular Joe Shmoe who follows the rules and does everything by the book.  These are the ones shown in the periodic table.  The other twin in each set has the same number of protons as its boring twin, but it doesn’t follow the rules about how many neutrons they are supposed to have. They’re greedy little thieves. So, they are technically the same element, but they end up weighing different.  For instance, Carbon-13 has his regular six protons like its brother, but it has a whopping seven neutrons because it just haaaad to go and be extra cool. 

Carbon and one of its isotopes, or Carbon and its fraternal twin.

Almost every element has some number of isotopes/twins, except weird ones like Thulium and Holmium – but who even are those guys? Now, the wrong-number-of-neutrons outlaw twin can either be “stable” or “unstable”.  It’s like the difference between the cool guy in class and the guy who is so “cool” that he ends up expelled from school.  The stable ones are functional in society – in this case meaning they occur in nature without a problem.  The unstable ones are completely dysfunctional and over time try to turn back into their more stable twins by shedding neutrons.  It’s kind of like they just went too neutron-crazy, got a little wild, and now they’re all bloated and not having a good time. 

Knowing about these different carbons is important because stable isotopes can help reveal food webs.  Naturally occurring carbon consists of both the normal carbon and its bad boy twin.  We have a method that allows us to measure the ratio between the outlaw and the normal (we call this ratio the isotopic ratio). By measuring the carbon isotopic ratio of an animal, we can answer questions like what did this animal eat, what level consumer are they, and even what kind of eater are they (suspension feeder, predator, etc). This is especially important in my work because I want to understand how carbon from land makes it into the deep-sea food web. When I drop a big hunk of land carbon in the form of an alligator or a wood log (wood fall), I first measure the ratio of good boy to bad boy carbon in that particular hunk of food.  I also collect samples of the sediments around where I drop the food and measure the ratio of carbons in that sample too.  Then, after letting the food stay on the bottom of the ocean for a while, I can take animals directly off of it and take similar animals far away from the it.  When I measure the ratio of carbons in these animals, I can compare them to the ratio of the two food sources I measured and can understand which food source the animals are using.

A wood fall is an example of land carbon, which we can trace up through an entire food web.  Photo courtesy of Dr. Craig McClain.

The reason this all works is because of the saying “you are what you eat.”  Turns out that is actually true!  We know how much the good boy to bad boy carbon ratio should change from a food item to its consumer. This is especially helpful as we begin moving up the food web, because we can start to see who is eating whom – and this is something not yet well understood in the deep sea.

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How many species are in the deep sea? https://deepseanews.com/2019/03/how-many-species-are-in-the-deep-sea/ https://deepseanews.com/2019/03/how-many-species-are-in-the-deep-sea/#comments Mon, 25 Mar 2019 15:00:34 +0000 https://www.deepseanews.com/?p=59083 In the beginning, people mused the expansive oceans contained but a handful of organisms.  This idea started with Pliny the Elder, who lived in the…

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In the beginning, people mused the expansive oceans contained but a handful of organisms.  This idea started with Pliny the Elder, who lived in the first century AD. He wrote that there were only 176 species in the entirety of the ocean.  This was four less than Aristotle had already found, counted, and documented in just the Aegean Sea. Apparently, Pliny wasn’t a big fan of Aristotle’s work. One paper describes this writing of Pliny’s as “gossipy” and I would just like to take a minute to thank the powers that be that none of my scientific writing has yet been described this way.  After making this utterly preposterous and completely false presumption, Pliny goes on to posture even more, writing “by Hercules! In the sea and in the Ocean, vast as it is, there exists nothing that is unknown to us, and, a truly marvelous fact, it is with those things which Nature has concealed in the deep that we are the best acquainted.” By this point in reading his bull….ogna, you better believe I had said “WHAT?!?!?” a million and five times in my head.  It is truly amazing how far we have come with our understanding of the natural world.  Don’t even get me started on how confused these guys were about just how the ocean could be “impregnated with salt” *face palm*

Pliny the Elder.  I wonder if he is frowning so intensely because he knows that in 2000 years his work is going to be roasted by some random woman in a blog post?

After Pliny’s monstrosity, many centuries went by before this question was really tackled again.  In 1815, Edward Forbes took a ride aboard the HMS Beacon, where he dredged the bottom at depths from 1-1,380 feet (0 – 420 m).  Just so you know, the average depth of the ocean is about 12,000 feet (4,000 m).  So, when I say he was barely scratching the surface, I’m not really exaggerating.  But nevertheless, he dredged the depths that he did and found that the deeper he dredged at, the less things he found.  So naturally, he thought, there must be a “zero point” at which no animals live.  He wildly extrapolated his data and determined that below 1,800 feet (600 m) there exist no animals, and he called this the “azoic zone.” So, Forbes’ answer to how many species in the deep sea was a big fat “not many.”

Luckily this “azoic zone” nonsense only lasted about 50 years.  In 1869, Charles Wyville Thomson and the rest of the crew onboard the HMS Porcupine pulled up animals from 14,610 feet (4,450 m) deep in the waters south of Ireland.  These results were later confirmed by the Challenger expedition which found animals at all depths, all over the globe.  This undeniably proved there was life at all depth of the oceans- but the question still remained.  How many species in the deep sea?

Fast forward to 1992.  Frederick Grassle and Nancy Maciolek conduct a massive (for the time) survey of the tiny animals that live in the sediments in the deep sea.  These are not the cute crawlies that live on top of the mud that had been previously sampled with dredges.  These are the small animals that live their lives between the grains of dirt at the bottom of the ocean.  Of the 798 species that they found, over half were new to science!  Pliny’s head would explode if he heard that more than double the total animals he thought existed in the whole ocean were found just in the mud.

Over the years, estimates of how many species are in the deep sea have spanned over six orders of magnitude! Circles are scaled to represent how large the estimate is in relation to the other estimates

Grassle and Maciolek did some impressive math and ended up calculating that they were finding one new species per square kilometer they sampled.  Let’s break that down.  One square kilometer is equal to a little more than one-third of a square mile.  So, they are basically finding three new species in each one-mile-square block of mud they are sampling.  This means if they were to sample an area the size of New York City, they would find around 782 new species, and if they were to sample an area the size of London, they would find about 1,572 new species.  These new species add up fast – you see, there are 300,000,000 square kilometers (115,830,647 square miles – almost 30 Europes or 431 Texases) of mud deeper than 1000 m in the ocean. The end result of all this is a conclusion of 300,000,000 species living in the mud at the bottom of the deep ocean.  This is not counting swimming things!  That’s a heck of a larger estimate than the 176 species estimate of centuries ago.

.It turns out that this calculation of Grassle and Maciolek was probably a bit of an overestimation.  They realized that much of the ocean is oligotrophic, or not very nutrient-rich and therefore not very productive.  This would mean that in many areas of the ocean, the rate of new species added per square kilometer is probably much less than what they found in their sampling area.   So, they ended up conservatively estimating the true number at more like 10,000,000 species in the mud. This is still a huge amount of diversity in the deep sea.

The rate of discovery of new animal species in the world oceans has been consistently rising over the past 200 years.  Graph from World Register of Marine Species.

Grassle and Maciolek’s 10 million species hypothesis sparked quite the controversy, with biologists from many sub-disciplines quickly arguing for or against the high number.  Isopod biologists Poore and Wilson said they had seen even more diversity just among isopods in their samples than the average number of species per 100 samples that Grassle and Maciolek had used in their calculations.  This, they argued, must mean there are even more than 10 million species!  In 1971, though, Thorson argued that there were only 160,000 species in the oceans across all depths- so far less than 10 million could be in the deep sea.  In 1992, May argued that only 500,000 species would be possible in the deep sea.  Lambshead in 1993 reminded everyone that there are a boatload of nematode worms and other animals (collectively called meiofauna) that live in the mud that were too small to be sampled by the gear Grassle and Maciolek used.  This, Lambshead argued, could mean a total of 100,000,000 marine species.  Consensus just could not be reached.

Here’s the problem, though.  It is a hard question to answer.  Each person who has attempted to answer this question was doing the best with the data that they had at the time (except Pliny- that guy was just an idiot okay). However, species diversity and especially how many species you discover in each new deep-sea “block” can vary considerably at different depths, regions, and oceans. Grassle and Maciolek’s encoutering 3 new species per block was based on data from the North Atlantic. Does 3 new species “rule” also apply to other parts of the Atlantic or to the Pacific? So without massive amounts of data, it is likely we will be kept guessing for a few more years to come. So, I can’t tell you exactly how many species are in the deep sea, but I can tell you that we currently have 409,543 named species in the ocean (World Register of Marine Species, accessed 03/18/2019).  The best part is that we are getting better and better at discovering new species, and hopefully in years to come we will be much better equipped to answer this question realistically.

Cover photo credit to Monterey Bay Aquarium Research Institute (MBARI).

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How is the deep sea so diverse? The struggle is real for late 1900s ecologists https://deepseanews.com/2019/03/how-is-the-deep-sea-so-diverse-the-struggle-is-real-for-late-1900s-ecologists/ https://deepseanews.com/2019/03/how-is-the-deep-sea-so-diverse-the-struggle-is-real-for-late-1900s-ecologists/#comments Tue, 12 Mar 2019 13:19:34 +0000 https://www.deepseanews.com/?p=59077 The year is 1967.  A paper is published that causes pandemonium in the scientific community.  The discovery causes a fundamental shift in thinking divergent from…

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The year is 1967.  A paper is published that causes pandemonium in the scientific community.  The discovery causes a fundamental shift in thinking divergent from long-held beliefs.  And like the discovery that the Earth does indeed revolve around the sun and not the other way around, the discovery of exceptional diversity of life on the deep-sea floor radically changed the way we view the natural world.

Prior to 1967, the environmental extremes of the deep were thought to limit life. The deep sea is dark (can’t-see-your-hand-in-front-of-your-face dark), cold (only-four-degrees-above-freezing cold), and under an extreme amount of pressure (one-elephant-on-each-square-inch-of-your-body pressure).  This suite of factors should make survival challenging, and thus for a century, scientists assumed the deep sea was biologically a desolate wasteland.  Even after the discoveries of animals living at extreme depths in the late 1800s, Victorian scientists expected that there could not be a diverse array of animals surviving in the deep sea.  Enter Robert Hessler and Howard Sanders who in 1967 used newly developed sampling devices to discover that the deep sea is shockingly diverse, and perhaps just as diverse as tropical shallow-water habitats. 

A lonely rattail swims over the abyssal seafloor.

Scientists were completely baffled as to how high diversity could occur in such a bleak place.  They began to throw out theories, but they were limited by the little data that had been gathered from a poorly explored deep ocean.  The scientific publications of this time on deep-sea diversity read like there were a few people in a room with a whiteboard, writing everything they remember from their ecological textbooks, talking through each theory, slowly crossing off possibilities, and working their way down the list.  

Small marine animals called macrofauna — snails, worms, clams, and other creatures no bigger than a pencil eraser — live and feed in the seafloor sediment. In an area the size of a coffee table, there may be more than 300 species of macrofauna in deep-sea sediments. Credit: Craig McClain

Howard Sanders began by writing “Specialization” on the whiteboard with his paper introducing the Stability-Time Hypothesis in 1968.  He suggested that because the deep sea is monotonous and predictable (i.e., it is stable), populations have the evolutionary time to become newly specialized in how they feed. Over time, these populations become so specialized they evolve into totally new species, eventually driving diversity up.  Further research and explorations indicated that the premise of this argument was wrong- the deep sea is actually not that stable.

Then, Paul Dayton and Robert Hessler walked up to the board and scratched off the “Specialization” idea with their paper in 1972 entitled “The role of biological disturbance in maintaining diversity in the deep sea.”  The pair do not argue against the idea that the deep sea is predictable and stable.  In fact, they favor the idea… except for the part where they proved that deep-sea species are actually not more specialized than shallow water species.

“Specialization” got a strikethrough on the whiteboard, and Dayton and Hessler wrote “Predation” below it.   The duo introduced a specific type of predation pressure they labelled “biological cropping.”  No, biological cropping is not deep-sea animals learning agricultural techniques… but a combination of predation and deposit feeding.  Animals can eat other animals either intentionally (e.g. hunting down prey) or unintentionally (e.g. stuffing everything you come across into your mouth and it just so happens that you get a live one).  This “cropping,” whether accidental or not, reduces competition by preventing one or a few abundant species from monopolizing the resource.  These species get knocked out, allowing far more species to get a piece of the proverbial pie. Nobody gets sent into extinction by competition.  Dayton and Hessler’s idea is not necessarily that diversity is driven to be high in the deep sea, just that it is not limited.

Dayton and Hessler’s “Predation” idea never got fully scratched off the list, but the difficulty of testing the idea and conflicting results have led many to write large question marks next to it.   Many other ideas now are situated below “Predation,” including: “Disturbance,” “Patchiness,” and “Successional Dynamics.”

Ultimately, those of us in the deep-sea scientific community are still today standing around the dry erase board bouncing many of these same ideas off each other.  Sometimes we manage to cross one off the list, or add one, or at least add to our understanding of the ideas.  One thing is clear though, we still haven’t gotten it all figured out.  So… anyone have a dry erase marker?

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Experience the Life of the Deep Gulf of Mexico in 20 Videos https://deepseanews.com/2019/02/experience-the-life-of-deep-gulf-of-mexico-in-20-videos/ https://deepseanews.com/2019/02/experience-the-life-of-deep-gulf-of-mexico-in-20-videos/#comments Thu, 07 Feb 2019 17:59:55 +0000 https://www.deepseanews.com/?p=58876 As we prepare for our 2019, Gulf of Mexico, Deep-Sea, Wood-Fall Collection, Research Cruise Spectacular from February 11th-24th, enjoy these videos from our 2017 expedition.…

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As we prepare for our 2019, Gulf of Mexico, Deep-Sea, Wood-Fall Collection, Research Cruise Spectacular from February 11th-24th, enjoy these videos from our 2017 expedition. Also follow us on Instagram and Twitter under hashtag #woodfall to keep updated on our upcoming cruise.

A brittle star demonstrates its unusual walking pattern. See this post for the science behind this walking.
Chimaeras are cartilaginous fish also known as ghost sharks, rat fish, spookfish or rabbit fish. In paleo-oceans, chimaeras were both diverse and abundant while today they are largely only found in the deep sea. While their closest living relatives are sharks, they last common ancestor was nearly 400 million years ago.
An unknown small black fish. Most of the species in the deep oceans have yet to be seen or even officially named by scientists.
Another unknown small black fish…of course I’m no ichthyologist.
A comb jelly dangles its long sticky tentacles searching for prey. The flickers of light are from cilia plates that lines its body and are reflecting light as opposed to bioluminescence.
A sea cucumber munches on mud lazily as two whip corals move gently in the current.
A deep-sea red crab throughs up a defensive posture against the ROV before finally retreating. Note the white barnacles attached on the shell of the crab.
A fast moving Giant Isopod tries to avoid the ROV. This is largest roly-poly on Earth! For reference, the laser points are 9 inches (22.86 cm) apart.
This glass sponge, a Venus’ Flower Basket, holds to commensal shrimp inside its structure.
Several fly-trap anemones are attached to a piece of a shipwreck. Animals that filter-feed out of the water often look for high perches to get up into stronger currents above the seafloor.
The unusual fish, Ipnops, a predator that feeds on molluscs and crustaceans in the sediment. The eyes are extremely modified into flat, cornea-like organs that cover most of the upper surface of the head. Ipnops are also hermaphrodites possessing simultaneously both female and male gonads in a single organ.
Purplebelly Skate known primarily from the deep Gulf of Mexico
The pelagic and gelatinous deep-sea cucumber, Enypniastes. You can see its intestinal track in yellow.
Slurping up the same Enypniastes with the ROV Hoover attachment. You can see here that the cucumber is quite small in comparison to the ROV arm.
Ignore the fact that we lost one of the lasers on the dive and enjoy this absolute unit of deep-sea cucumber.
The amazing tripod fish. Tripod fish, a sit-and-wait predator, seem to prefer being perche dup on their elongated fins rays in the tail and two pelvic fins. They face upstream with the pectoral finds turned toward forward with the fin rays resembling antenna dish. Indeed, it is a dish as fin rays are tactile organs.
A Giant Isopod almost swims into our benthic elevator.
Even at two kilometers deep and 200 kilometers offshore, there is evidence of human impact. Here a blue plastic bag wisps across the ocean floor like an amorphous deep-sea animal.
Aluminum cans are frequent feature of the deep oceans.
And another can.

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The Fantastical Beasts of the Deep Gulf of Mexico https://deepseanews.com/2017/06/the-fantastical-beasts-of-the-deep-gulf-of-mexico/ Fri, 16 Jun 2017 02:17:40 +0000 https://www.deepseanews.com/?p=58206 I recently returned from nearly two weeks at sea with a motley and intrepid crew exploring the Gulf of Mexico almost a mile and half…

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I recently returned from nearly two weeks at sea with a motley and intrepid crew exploring the Gulf of Mexico almost a mile and half deep.  You can read up on our adventures on our Reddit AMA. The main goal was to deploy nearly 200 wood falls on the deep-sea floor.  The work, funded by the National Science Foundation, seeks to examine how marine organisms respond to changing food supplies as a result of climate change.  Wood falls in the deep sea offer up nice little experimental systems in which to test ideas.  The work was conducted with a remote operated vehicle and allowed us the opportunity to explore the amazing creatures found in the deep Gulf of Mexico.  Below is both an amazing set of photos taken on the surface by the talented photographer Jason Bradley, part of the expedition, and a host photos taken by the scientists and ROV team with the 4K camera aboard Oceaneering’s Global Explorer.

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A Decade of Deep Sea Decadence https://deepseanews.com/2016/12/a-decade-of-deepling-decadence-at-dsn/ Tue, 13 Dec 2016 17:12:56 +0000 https://www.deepseanews.com/?p=57439   Today is legendary! Why, you ask? Well, we are celebrating TEN YEARS of DSN posts. That’s right – if you go wayyyyyyyyy back in…

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Today is legendary! Why, you ask? Well, we are celebrating TEN YEARS of DSN posts. That’s right – if you go wayyyyyyyyy back in the archives you will note that the proto-Deep Sea News empire began with a little post by Dr. M on December 13, 2006.

What were we all doing in 2006? Well as for myself (this is Holly speaking), I was just starting my PhD research in good ol’ London towne. I was listening to a lot of Pussycat Dolls, and Christina Aguilera was going through that weird jazz phase. I was smoovely fixing nematodes on glass slides to the tune of Chamillionaire, and I had just signed up to this cool new website called Facebook.

As you can fathom, a lot has changed in 10 years. The DSN crew has moved forward and onwards in our careers, many of us metamorphosing from wee little student trainees into Real Scientists™. Our list of contributors has changed and evolved. We write different types of posts now (should we remind Dr. M that he used to use DSN as a cruise blog?). In light of recent world events, our message and mission has become increasingly urgent.

But other things haven’t changed – our Core Values, although not formalized in writing until 2011, have always been a fundamental part of Deep Sea News. The passion, enthusiasm, and dedication of all of our past and present writers will never change. And of course I still listen to the Pussycat Dolls (because how can you NOT?)

So in celebration of our site’s 10 year anniversary, here we present you with our Top Ten (and then some) posts in DSN History:

2006 

Wetting my toes

Kim: Do I need to explain that the very first post on DSN is also that years highlight? It’s real, it’s sweet and it kicked off ten years of online shenanigans!

2007 

Just Science Weekend: They Eat Their Young

Jarrett: I <3 DSN in 2007. You can feel the online science world trying to figure out what it was. DSN was a more news-y place, with a heavy dose of reportage on the deep sea, like this awesome interview of sub pilot David Guggenheim. But amidst that, DSN was also figuring out who it was going to become – and this gem of a piece from Peter Etnoyer epitomizes the future, showing us that not only are deep sea fish all around us in our everyday lives, but man, do they sure like to cannibalize their babies. Mmmmmm….babiez.

2008

Dumping Pharmaceutical Waste In The Deep Sea

Rebecca: 2008 was a year or short-and-sweet posts, punctuated by long and well-researched articles on everything from coral age to deep ocean waves. DSN found a unique voice in being a place not just to report on the latest news, but also provide a scientist’s perspective on the way news about the ocean is reported in the press. This was also a year of raising awareness, with Dr. M’s post on pharmaceutical dumping in the deep as a perfect example of how blogs can call attention to unique and important stories that the press might miss.  

2009 

Holly: My favorite thing about 2009 is the epicness of Kevin Zelnio, best summarized with these two posts:

TGIF: TOTELY AWSUM SEE KUKUMBR!!!11!!!!11!

This post is a HILARIOUS animated video about a very boring sea cucumber, complete with rock guitar soundtrack. I think I just re-watched it like five times.

Thank You for Caring About Ocean Education!

(the more serious and dedicated size of Zelnio, where he coordinated a campaign at DonorsChoose.org and raised over $4800 from our readers. This campaign funded Ocean Education projects in K-12 classrooms around the country!)

2010 

All the coverage of the Deep Water Horizon Spill

Kim: Let’s be real, the Macondo well blowout sucked for the Gulf. But in terms of science, DSN was on it providing weekly updates and posting readable summaries of technical reports. The entire archive is here folks.

How To Cuddle Your Lady Right, by Smoove A

In this epic post, Miriam describes how one microscopic crustacean makes all the right moves and makes the mating happen. All biology textbooks should be written like this.

2011

From the Editor’s Desk: The Giant Squid Can Be A Panda For The Ocean

Holly: First of all, I love the 2011 Editor’s Desk posts because Craig very epically summarized himself with a minimalist icon of his bald head and beard. Second, the Giant Squid is WAYYYY more awesome than those damn dolphins and whales that everyone keeps going on about. And I prefer my cuddly mascots with lethal beaks and suckers, thank you very much.

From the Editor’s Desk: The Future of Deep-Sea News

This is the post where we formalized our now infamous core values – they were the brain child of the very first DSN retreat at the Georgia Aquarium, a weekend of meeting rooms and champagne in a rotating sky hotel. One of those things turned out better than the other.

2012 

#IamScience: Embracing Personal Experience on Our Rise Through Science

Jarrett: This post embodies DSN at it’s best. Kevin Z. takes us on his deeply personal and emotional journey into science. It’s a kind of story rarely told, and one that so many need to hear.

How presidential elections are impacted by a 100 million year old coastline

In this post, Craig connects American history with geological history, and ties it all together to understand how both impacted the 2012 presidential election. This post exploded the internet.

2013 

Kim: 2013 was just so awesome, I couldn’t just pick one!

10 Reasons Why Dolphins Are A$$holes

Do I even need to explain?

A field guide to privilege in marine science: some reasons we lack diversity.

When Miriam left DSN, she went out with a deeply important and thoughtful list. If you are an ally and want to see marine science grow, read this piece.

How many people does Kaiju need to eat everyday 

Sure we love all the creatures of the deep, but we also love Hollywood’s imaginary beasts as well. Craig answers some serious questions regarding the metabolism of the monsters in Pacific Rim.

The 60 foot long jet powered animal you’ve probably never heard of

In case you didn’t know what Rebecca’s niche in the online ecosystem, this is it. Someone found a giant gelatinous tube in the sea, she identifies it, and the internetz go wild. Rebecca, helping jellies go viral since 2013.

True Facts about Ocean Radiation and the Fukushima Disaster 

SPOILER ALERT: unless you live within 100 miles of the reactor, radiation from the Fukushima Disaster is still not harmful. This post was meant to be a guide to understanding radiation in the ocean. It ended up being one of most shared posts ever and the one we received death threats over.

2014

The Ever Increasing Size of Godzilla: Implications for Sexual Selection and Urine Production

Beth: Where Craig discusses the body size characteristics of godzilla over time, and the logical implications this would have on the millions of gallons of urine that massive godzilla would generate. This post has the thing that makes me love DSN – using scientific reasoning to explain a totally ridiculous thing. And it features Craig’s weird obsession with the size of things.

Runner up:

Sex, snails,sustenance…and rock and roll 

Where Craig uses great metaphors to explain some cool scientific studies on how snails reproduce based on food availability, featuring inappropriate references to rock stars and sex, and with a bonus soundtrack!

2015 

Ten Simple Rules for Effective Online Outreach

Alex: It’s like we all wrote a blog post… together. And then published it for realsies.

2016 

On Being Scared.

Alex: In which Craig verbalizes the place we have all been. I love and admire the vulnerability in this post and that he ended it so positively… that even when shit hits the proverbial sea fan, we get to choose how we respond. We get to choose how we show up.

Runner up:

The Twelve Days of Christmas: NASA Earth Science Edition

Alex: When you get retweeted by NASA… you get a spot on the list.

(Runner up #2)

The worst ocean environments to catch them all

Rebecca: When you love Pokémon but hate crushing barometric pressure.

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Craig With Big Things (and Small Things) https://deepseanews.com/2016/11/craig-with-big-things-and-small-things/ Fri, 11 Nov 2016 03:37:07 +0000 https://www.deepseanews.com/?p=57222 I have a confession. I am obsessed with ridiculously large and small things. While other children impatiently anticipated toys for Christmas, I enjoyed just as…

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I have a confession. I am obsessed with ridiculously large and small things. While other children impatiently anticipated toys for Christmas, I enjoyed just as much the miniature Christmas village my mother would place under the tree. I was particularly fascinated with the tiny frozen pond and ice skaters. I eagerly awaited the display being pulled from the box and the opportunity to set up the whole small scene. Years later as an adult, I am still fascinated by that miniature pond and skaters. And I still dream of owning my own tiny Christmas village. Much to wife’s dismay I’m sure, I spend substantial amounts of time drooling over displays of tiny villages in holiday shops. O’ how I must possess my very own miniature gas station or bakery!

screen-shot-2016-11-10-at-9-32-03-pm screen-shot-2016-11-10-at-9-32-37-pmI 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.

screen-shot-2016-11-10-at-9-29-21-pmI 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.

Common deep-sea snails verses some common shallow-water snails
Common deep-sea snails verses some common shallow-water snails

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.

screen-shot-2016-11-10-at-9-28-35-pmIn 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?

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