At the surface, each of those cups was 90% air and 10% tiny polystyrene beads. After each cup is artistically adorned with deep-sea imagery, they take a plunge to the abyss. At the crushing pressures of the depths, the air is squeezed out, leaving only those tiny polystyrene beads, and each cup becomes a miniature of its former self. One of the most extreme environmental gradients is the increase of pressure with increasing depth, starting at 1 atmosphere at the surface and reaching well over 1,000 atmospheres in the deepest parts of the ocean. How do organisms survive this great pressure, and what happens to them when they are brought to the surface?

The highest known pressure in the deep oceans coincides with the maximum known depth at the southern end of the Mariana Trench, the Challenger Deep. The actual maximum depth of Challenger Deep is disputed. The deepest reported measurement was by a Russian research vessel at 11,034 meters. The International Hydrographic Organization adopted 10,924 meters in 1993, but a subsequent 2010 survey, the most accurate to date, places the depth at 10,984 meters—25 meters greater. With every 10 meters corresponding to 1 atmosphere of pressure, this places the maximum known pressures in the deep between 1092.4 and 1103.4 atmospheres (110.7–111.8 MPa). Notably, several other deep-sea trenches—Tonga, Philippines, Kuril-Kamchatka, and Kermadec—in the Pacific Ocean also reach depths greater than 10,000 meters. In the Atlantic Ocean, the two deepest trenches are the Puerto Rico Trench at 8,800 meters and the South Sandwich Trench at 8,428 meters.

Exploring the depths of the ocean reveals a fascinating array of life forms, showcasing the incredible adaptability of both prokaryotic and eukaryotic organisms to high-pressure environments. Even in the Challenger Deep, where pressures exceed 110 MPa, microbial life thrives. Interestingly, several large multicellular organisms have been discovered at these extreme depths. A striking 74% of species found below 7,000 meters are endemic to these very deep areas. Among these invertebrates are the sea cucumber Myriotrochus bruuni, which inhabits the Mariana Trench at 10,710 meters, and the amphipod Hirondellea gigas, one of the most abundant creatures in the Challenger Deep at 10,897 meters. The hadal snailfish Pseudoliparis swirei holds the record for the deepest known vertebrate, living at an astonishing 7,966 meters.

How do organisms survive this depth? In short, there is a host of remarkable physiological and biochemical strategies that allow organisms to survive and thrive under the immense pressures found in the ocean’s depths. These adaptations include unique cellular structures and molecular mechanisms that confer resilience to high-pressure environments, such as specialized cell membranes, pressure-resistant enzymes, and unique protein folding techniques.

As you may remember from high school or college biology, a cellular membrane consists of a lipid bilayer. The structure is maintained entirely by the interaction of charges (or lack thereof) between water and the phospholipids. This makes the membrane semipermeable, much like a layer of oil on water. Extreme pressure results in tighter packing of the phospholipids, which lowers the permeability of the membrane. One adaptation by deep-sea animals to increase cellular permeability is to increase the percentage of unsaturated fatty acids. In a saturated fatty acid, all the carbons in the chain are linked by single covalent bonds. As you recall, a carbon can form four chemical bonds. If all these bonds are covalent (single), then a carbon could potentially attach to four other atoms. The term “saturated” comes from the fact that the carbon chain is loaded with hydrogens. If a carbon forms a double bond with another atom, it would bond with one less hydrogen. Thus, an unsaturated fatty acid has double bonds and is not “saturated” with hydrogens. The double covalent bond between adjacent carbons in an unsaturated fatty acid leads to a kink in the tails of the molecule. Thus increasing their concentration in the membrane leads to looser packing.

Pressure also selects for different enzymes. Changes in protein structure can influence their cellular function. Selection for rigidity is needed to counteract pressure and the resulting warping of proteins. Proteins contain hydrogen and disulfide bonds between different subunits and parts of the amino acid chain that dictate structure. Selection for proteins with increased bonding minimizes changes in shape due to pressure. Pressure can even make molecules more (or less) toxic. Urea is a good example: it becomes far more toxic as pressure increases. Deep-sea sharks, which like all sharks have a lot of urea in their blood, also have more of the protective chemical TMAO to offset this effect than their shallow-water cousins.

Pressure also does not favor air-filled volumes and sacs. The deepest diving submersibles require titanium spheres to hold the air-filled volume for their human inhabitants. For deep-sea animals, titanium is not an option, so most avoid having air-filled sacs. For example, deep-sea fish lack swim bladders. Other deep-diving animals like whales and seals have collapsible lungs to deal with extreme pressure (not to mention a whole host of other adaptations)!”

The post How Life Thrives Under the Ocean’s Crushing Pressure first appeared on Deep Sea News.

Jack and squat is known about free-living flatworms form the deep sea. Their fragile bodies are unlikely to be collected successfully in dredges and trawls. This means that outside of ‘potential platyhelminth’ from a wood fall and deep record of another species little else is known.

A new study adds to our limited knowledge of these beasties. Flatworm egg capsules were retrieved from rocks found approximately 6200 meters deep in a trench in the northwestern Pacific. Despite each capsule being a diminutive 3mm in size, they housed anywhere from 3 to 7 individuals. Through the application of genetic tools, the researchers identified a new species within a group previously only observed in shallow waters.

Kakui, Keiichi, and Aoi Tsuyuki. “Flatworm cocoons in the abyss: same plan under pressure.” Biology Letters 20.1 (2024): 20230506.

The post Flatworm cocoons in the abyss first appeared on Deep Sea News.

The highest known pressure in the deep oceans coincides with the maximum known depth in the southern end of the Mariana Trench, the Challenger Deep. The actual maximum depth of Challenger Deep is disputed. The deepest reported measurement was by a Russian research vessel at 11,034 m. The International Hydrographic Organization adopted 10,924 in 1993, but a subsequent 2010 survey, and the most accurate, places the depth at 10,984 – 25 m greater. With every 10 m corresponding to 1 atmosphere of pressure, this places the maximum known pressures in the deep between 1092.4 and 1103.4 atm (110.7–111.8 MPa). Notable is that several other deep-sea trenches—Tonga, Philippines, KurilKamchatka, and Kermadec—in the Pacific Ocean also reach depths >10,000 m. In the Atlantic Ocean, the two deepest trenches are the Puerto Rico Trench at 8800 m and the South Sandwich Trench at 8428 m.

The prevalence of prokaryotic and eukaryotic life through the range of high pressures in the deep oceans suggests that organisms can easily adapt to these conditions. Even at the extreme pressures (>110 MPa) in the Challenger Deep, microbial life flourishes and differs from the background abyss. Several large multicellular organisms have been found at extreme depths and pressures and can be characterized as primarily hadal and trench species. Endemism of species occurring greater than 7000 m is 74% of surveyed species, implying a strong evolutionary pressure and the unique adaptations required to exist at extreme depths. Among invertebrates, several reach trench depths, including the sea cucumber Myriotrochus bruuni at 10,710 in the Mariana Trench, the extremely abundant amphipod Hirondellea gigas at 10,897 m in the Challenger Deep, the isopod Macrostylis species at 10,710 in the Mariana Trench, the polychaete genus Macellicephaloides at 10,700 m depth, and the sea anemone family Galatheanthemidae at 10,700 m depth. The deepest known vertebrate is the hadal snailfish Pseudoliparis swirei found at 7966 m.

How do organisms survive this deep?

1. Cell membranes: As you may remember from high school or college biology, a cellular membrane consists of lipid bilayer. The structure is entirely maintained by the interaction of charges (or lack of) between water and the phospholipids. This makes the membrane semipermeable much like a layer of oil on water. Extreme pressure results in a tighter packing of the phospholipids which lowers the permeability of the membrane. One adaptation by deep-sea animals is to increase cellular permeability is to increase the percentage of unsaturated fatty acids. In a saturated fatty acid all the carbons in the chain are lined by a single covalent bond. As you recall, a carbon can take four chemical bonds. If all these bonds are covalent (single) then a carbon could potentially attach to 4 other atoms. Thus the saturated comes from the fact that the carbon chain is loaded with hydrogens. If a carbon forms a double bond with another atom then the carbon would have to bond with one less hydrogen. Thus an unsaturated fatty acid is one with double bonds and not ‘saturated’ with hydrogens. The double covalent bond between adjacent carbons in an unsaturated fatty acid leads to a ‘kink’ in the tails of the molecule. Thus increasing their concentration in membrane leads to a looser packing.
2. Enzyme shape: At the basic level, pressures would also select for different enzymes. Changes in protein structure can influence their cellular function. Thus selection for rigidity is needed to counteract pressure and the resulting warping of proteins. Proteins contain hydrogen and disulfide bonds between different subunits and parts of the amino acid chain that both dictate structure. A selection for proteins with increased bonding would minimize changes in shape to do pressure.
3. Urea: As note by Al Dove previously, “Pressure can even make molecules more (or less) toxic.  Urea is a good example: it becomes far more toxic as pressure increases.  So deep sea sharks, which like all sharks have a lot of urea in their blood, also have a lot more of the protective chemical TMAO to offset this effect than do their shallow water cousins.”
4. Air filled sacs: Basically this is bad for an animal under pressure, so most deep-sea animals avoid having them. Deep-sea fish lack swim bladders. Other deep diving animals like whales and seals have collapsible lungs to deal with extreme pressure (not to mention a whole host of other adaptations)! Penguins basically shut down all their organs except for their heart and their brain when doing deep dives.

The post The Hidden World of Extreme Ocean Depths: Life and Pressures in the Trenches first appeared on Deep Sea News.

I’m kind of obsessed with Okeanos Explorer. Why? Because being able to watch a live feed of an ROV exploring the deep ocean on the TV in my living room is pretty amazing. THE FUTURE IS NOW PEOPLE.

Okeanos Explorer is a NOAA boat whose sole business is ocean exploration. It uses two ROVs equipped with mega giant cameras and a network of satellite intertubes to bring you live feed of seafloor exploration. It beams back all sorts of amazing images of weird deep sea sea beasties and geology. Quite often they find specimens they have never even seen before! Just last mission they even explored a wrecked WWII plane! Current mission: The Wake Islands in the Pacific Remote Islands National Marine Monument.

The next dive will happen this Sunday. You can catch all the feeds on your compy at their streaming link http://oceanexplorer.noaa.gov/okeanos/media/exstream/exstream.html

If you have a smart TV, ROKU, Apple TV or really any other streaming device you can WATCH IT ON YOUR TV. Just pull up the YouTube app and search for Okeanos Explorer. Camera 1 is where the action is, but Camera 2 (ROV #2) and Camera 3 (Control room) are pretty neat too.

You can also follow along on Twitter at #Okeanos, lots of biologists online to identify all the things! Or post-dive check out Christopher Mah over at Echinoblog with some sea-beastie round ups.

The post Have you been watching Okeanos explorer? If not, this week is your chance! first appeared on Deep Sea News.

This week the best part of the 90s has returned in full force with the Niantic’s release of Pokémon Go. You guys, this is like that thing when they re-released Oregon Trail for mobile devices…but better.

For those not in the know, Pokémon Go basically blurs the lines between the real world and the virtual world by allowing “Pokétrainers” to catch em’ all as they go through their everyday lives. Quite effectively getting the nerds out into nature to exercise. Sneaky sneaky.

Reports have poured in regarding the rather interesting places people have found themselves looking for wild Pokémon. From strip clubs to delivery rooms, you never know where a Squirtle may be hiding. Perhaps even next to a dead body. 

With that said, I think we can all agree, there are good places to look for Pokémon and very bad, bad places to look for Pokémon. We here at Deep Sea News believe it is our sacred duty to keep the public well informed of all things ocean-faring and would like to point out some of the places that perhaps you shouldn’t go looking for your next Seel or Horsea. You’re welcome.

1. Mariana Trench 

Nearly 7 miles down (36,070 feet), the Mariana Trench clocks in as the deepest point in the world’s oceans. Not only would you not be able to see anything, but the pressures 1,000x that of sea level would crush you and your hopes of catching all the Seadra lurking around in the ocean’s depths. Of course, if you are besties with James Cameron…you might have a chance.

2. Rocky Intertidal Zone

Unlike most of the sea stars on the West Coast of the United States, Starmie’s are immune to Sea Star Wasting Disease so you might actually by lucky enough to find one. However, you must remember that they occupy one of the most extreme ecosystems in the world, the Rocky Intertidal Zone. Thus, in order to be the very best like no one ever was, you must first combat some potentially massive wave action.

3. Hydrothermal Vents

Ironically, there are probably a crap ton of Pokémon at hydrothermal vents and most likely the rarest and most exotic species of all. These vents are teaming with biological diversity uniquely adapted to this most extreme environment comprised of high temperatures and seemingly toxic water. They are adapted…you aren’t.

4. Cook Inlet (Anchorage, Alaska)

Boasting some of the most dramatic tidal exchanges in the United States, this area off the coast of Anchorage, Alaska is no place for Pokétrainers. Krabby and the rest of the water Pokémon won’t get stuck in the quicksand-like glacial silt, but you might. Combine that with a 12.2 m tidal shift and Team Rocket trying to steal your Pokémon will be the least of your worries.   

5. Dead Zone (Gulf of Mexico)

Hypoxic Areas, or Dead Zones, occur when the level of dissolved oxygen in the water column is so low that the area can no longer support aerobic life (note: of which I assume for the sake of this post Pokémon to be). The United States claims domain over one of the second largest hypoxic zones world wide, the Mississippi River mouth in the Northern Gulf of Mexico. This is due, in major part, to large agricultural nutrient run-off. Do not let the photoshopped Squirtle in this picture fool you. There are no Pokémon here. They are all dead.

6. Polar Region

Let’s be real. It’s cold. There is ice everywhere. You don’t have an ice breaker. Though with climate change the way it’s going, catching that Seel might just be a waiting game.  

7. Mediterranean Sea

“The United Nations Environment Programme has estimated that 650,000,000 tons of sewage, 129,000 tons of mineral oil, 60,000 tons of mercury, 3,800 tons of lead and 36,000 tons of phosphates are dumped into the Mediterranean each year.” Probability has it that the Mediterranean Sea is the world’s most polluted ocean, meaning that there are most likely low levels of Pokémon and high levels of “you don’t want to swim there”.

The post The Worst Ocean Environments to “Catch Em’ All” 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.

First, let’s talk about animals that can go below 8,400 meters. Lets talk about the deepest living animals on earth. The hadal amphipod is one of them:

This specimen was collected in the Sirena Deep [1]. At 10,500 meters, the Sirena Deep is one of the deepest places on Earth, resting a little under 100 miles south of Guam. This creature is one of the Sirena Deeps’ few residents. The yellow patches on either side of its head may be simple eyes [1]. The purpose of the red globe-like structures, along with much of the animal’s biology, remains a mystery. They are abundant below 8,400 meters.

Why do hadal amphipods thrive where fish do not? One person who has thought a lot about this is Dr. Paul Yancey, a deep-sea expert at Whitman College. The only real difference between 8,370 meters–the greatest depth at which fish have been found–and 8,400 meters, is pressure. Add an extra 30 meters, or about 100 feet, of seawater and you’ve added three extra atmosphere’s worth of pressure. Anyone who has tried to dive to the bottom of a pool and felt a squeeze in their ears can tell you that even a small change in pressure can make a big difference. The good news for fish is that water is not compressible like the air inside our ears. I had always assumed that, as long as an animal is made mostly of water, without any trapped gas to expand and compress, depth shouldn’t be an issue. But I was wrong, because pressure squeezes other things.

DNA. Proteins. Membranes. The very building materials of living animals are impacted by pressure. Proteins are particularly prone to problems. Proteins, which perform most of the work in our cells, including the pulling power of muscle, are crushed at high pressures. The muscles of shallow-water fish, for example, do not develop correctly under increased pressure [2]. And so deep sea animals must adapt.

Dr. Yancey has two hypotheses for how deep-sea fish cope with the massive pressure squeeze [3]. One possible adaptation is to counteract. You know that fishy smell from fish? That smell is from a special molecule known as trimethylamine oxide (TMAO). TMAO and regular old table salt have something in common. Have you ever spilled salt on a countertop in a humid climate, and come back to find little drops of moisture around the salt grains? Salt attracts water, and water-attracting molecules are called “osmolytes.” TMAO is also an osmolyte and it helps fish at shallow depths hold onto the water in their bodies, counteracting that other pesky osmolyte–salt–that they swim through all the time.

Dr. Yancey discovered that TMAO also helps cells function normally under pressure, by protecting proteins from crushing water molecules all around them. TMAO serves as a kind of protein stabilizer. Without TMAO, water molecules under pressure force their way into tiny protein folds, breaking apart protein structures and disrupting protein function. With TMAO, water molecules are not able to force themselves into these small cracks, and proteins keep working, even at great depths. Dr. Yancey suspects TMAO helps fish survive in the deep sea. But why the depth limit then? And what does this have to do with the mysterious 8,400 meter line?

“As fish go deeper, they need more TMAO,” Dr. Yancey explains [2]. More pressure may require more TMAO to keep cells working. But you can have too much of a good thing. Remember how TMAO is an osmolyte, a water-attracting molecule? It’s possible, Dr. Yancey hypothesizes, that at 8,400 meters fish “would need so much TMAO to counteract the pressure of the water that water would start flowing uncontrollably into their bodies” [2]. The same molecule that may protect against water pressure may ultimately cause water poisoning. In other words, the strange properties of TMAO may be responsible for the mysterious line in the deep sea, below which fish cannot go.

This hypothesis, however, is very hard to test. And Dr. Yancey concedes that “in another trench, maybe there is a fish that disproves my proposed depth limit.” If fish are there, they certainly are hard to find. And that’s good news for other denizens of the deep, like the hadal amphipod pictured above. These amphipods, and other animals below 8,400 meters, may have different adaptations to deal with such crushing pressures. This is especially fortunate for hadal amphipods, which are a favorite snack of fish above 8,400 meters. For now, the amphipods’ mysterious ability to survive in the deepest deep sea has afforded them the luxury of a fish-free freezing black abyss all their own.

https://www.youtube.com/watch?v=cBxsm5T2yN8

(The video above is of a very deep fish, taken at 8,143 meters, and is a contender for the deepest fish, along with a tongue-twister of a fish: Bassogigas profundissimus, collected with a net from possibly as deep as 8,370 meters in the Puerto Rico Trench [5].)

References

[1] Photo: A hadal amphipod from 10,500 m in the Sirena Deep http://www.schmidtocean.org/file/show/3498

[2] Life Under Pressure – 100 Elephants on Your Head. Schmidt Ocean Institute expedition update. By Dr. Paul Yancey. http://schmidtocean.org/story/show/3236

[3] PH Yancey, ME Gerringer, JC Drazen, AA Rowden & A Jamieson (2014) Marine fish may be biochemically constrained from inhabiting the deepest ocean depths. PNAS. 4461–4465, doi: 10.1073/pnas.1322003111. http://www.pnas.org/content/111/12/4461.full

[4] The Deepest Living Animals. Schmidt Ocean Institute expedition update. By Dr. Paul Yancey. http://www.schmidtocean.org/story/show/3494/

[5] Staiger JC. 1972. Bassogigas profundissimus (Pisces; Brotulidae) from the Puerto Rico Trench. Bulletin of Marine Science22: 26–33. (PDF)

The post Why are there no fish in the deepest deep sea? first appeared on Deep Sea News.

Over a week ago, Thaler tagged in my a Tweet.

O’ how I coveted my neighbor’s Life magazine.  In case you cannot tell that is February 15, 1960 issue featuring Picard, Walsh, and the Trieste on the cover.  The two men in the Trieste reached a record maximum depth of about 10,911 metres (35,797 ft), in the deepest known part of the Earth’s oceans, the Challenger Deep, in the Mariana Trench.  This Life issue was published just weeks after this record dive (January 23, 1960).

I am in awe that Thaler parted with such a momento and gifted it to me.

The post An Unexpected Surprise in My Mail first appeared on Deep Sea News.

You already know that Deep Sea News provides expert reporting, in-depth analysis, first-person research, and sarcastic mockery of contemporary topics relevant to our ocean world. Unlike other popular science sites that can be wildly imaginative and dangerously inaccurate, DSN’s crew of scientists cut through the pop-science b.s. and re-posted misinformation to deliver ocean news that you can trust.

But did you know the DSN Facebook site provides even more delicious science nuggets each week for your inquiring mind to chew and savor? Beginning this week, as a premium for our Facebook friends, each and every Monday from now until eternity* will feature the shell of a different marine marine organism in an ongoing DSN internet event called Malacology Monday.

Dipping into the vast marine science collection from the Lobos Marinos International Marine Science (& Cocktails), we will bring you the dazzling array of evolutionary innovations, complex architecture, and endless aesthetics that sea shells deliver. For each species featured we will also communicate bona-fide scientific information and curious facts about the ecology and adaptations of extant and extinct mollusks, as well as the long human history with marine shellfish and their impact on our own culture.

If you like mollusks, and in particular malacology, this is a much-need intravenous drip of taxonomic enlightenment and morphological bliss, and if you aren’t yet in the cult, Malacology Monday will be the digital gateway drug to a soul fulfilling and mind expanding appreciation of our underwater world. So start each week with a stiff shot of mollusks on Deep Sea News’ Facebook Page.

*Eternity not exclusive of time away for expeditions, conferences, vacation, last-minute pre-deadline grant-writing, finals week grading, benders, mandatory time at the honor rancho, amnesia, malaise, or the untimely demise of the concept’s host.

Related articles

The post Malacology Monday first appeared on Deep Sea News.

This is not the ocean:

Indeed, even THIS is not the ocean:

Before you start thinking that the folks at DSN are losing their marbles, bear with me!  The truth is that none of these three all-too-familiar and quintessentially marine images reflects the actual reality of what most of the ocean is like.  Here’s why.  At their most basic, the above three images can be represented like this (respectively):

Our experience of the ocean is almost entirely defined by our interactions along its margins: along the coast, sitting the bottom or floating on the surface.  More often, it’s some combination of these, like a coral reef, which can be all three: coastal, benthic and also in reach of or transcending the surface at least some of the time.  In all of these marginal habitats, life is heavily influenced by the margin itself: benthic things have specific adaptations to interacting with the substrate, while pelagic things have adaptations for interacting with the surface, and so on.  In many of these places it’s sunny, it’s warm and there are lots of animals, at least relatively speaking.   The point of my post is that the rest of the ocean, an overwhelming majority in fact, looks like this:

That’s because the part of the oceans not included in coastal zones, on the bottom, or within sunlight’s reach of the surface make’s up about 94% of the volume of the ocean (and of course, the other 6% looks like this at night time, or 50% of the time!).  Average ocean depth is around 12,100 feet, with sunlight penetrating the top 650 feet or so.  The other 11,450 feet consists of pitch dark and perpetual blackness, with no margin or structure to disrupt the inky 3-dimensional void.  It’s also uniformly and numbingly cold; below the reach of sunlight it is about 4°C or 39°F everywhere in the world, regardless of whether you are off Greenland or Hawaii.  About the only thing that isn’t uniform throughout this habitat is pressure, which varies greatly with the depth of any given cube of water, but is generally a great deal more than any experienced along coasts or at the surface, although it must be said that bottom-dwelling communities in the deepest parts of the ocean experience the greatest pressures of all.

There are animals in the void too, of course, but they are sparse in the extreme and without extrinsic light and without any habitat structures they are foreign in form.  Often delicate and flimsy, diaphanous or gelatinous, they exist in a world without walls, floor or ceiling, without any structure at all to define the boundaries of their environment or even to serve as some spatial point of reference.  There are animals here that will not during their lifetime experience a solid surface, or even a fluid one such as the boundary where water meets air; they and their ancestors appear and disappear from the void, never alighting on anything.  To them, a wall might be as incomprehensible as a black hole is to us.  They are born, live out their life histories and die in a frigid, timeless, structureless void.

I’m not a religious guy, but the bible opens with a statement to the effect that “the earth was formless and empty, darkness was over the surface of the deep” and I can’t help but be struck that the world described by this passage, before God supposedly created light and began to shape the world, bears a striking resemblance to the vast majority of the oceans that exist today.  We think we know the oceans, but we don’t, not really, because the majority of the oceans are an icy black void inhabited by creatures as alien as any we can expect to find in that other unceasing void, the one we call space.

The post We don't know the ocean first appeared on Deep Sea News.