As the research vessels Nadir and Ocean Voyager entered the Grand Banks during the summer of 1996, some of us aboard awoke to a rare and personal appreciation for the questions penned in the Book of Job more than 2,700 years ago. According to the biblical scribes, when God met Job in the desert, He defined the wonders of the Earth, and the stars, and the depths; and He demanded of humankind that we go out into the wilderness and comprehend them:
Darkness, crushing pressures, and - we should add - life, are the dominant conditions of the abyssal plains. And of this life, what is the most dominant form? What has the largest biomass? As humans blinded by our sight to but a limited spectrum of reality, our first answer would not likely be the bacteria (too small to be significant). Yet, according to the latest available evidence, the bacterial biomass of the oceans (just the oceans) outweighs all the fishes, and the crabs, and all of the other living creatures in the seas combined - plus the mass of all plants, animals and humans dwelling on the continents. The question: "Hast thou comprehended the expanse of the earth?" now has deeper meaning.
In hindsight, the evidence was scattered all around us and inside our very being. The mitochondria that power every cell in our bodies more closely resemble free-living self-replicating bacteria than parts of our cells. Perhaps the sine qua non for our existence was simply an ancient infection transformed from parasitism to symbiosis. From independence to dependence to total assimilation, it begins to look as if our bodies are inhabited by strangers (including certain structures attached to our DNA, and the bacteria-like cilia lining our air passages). They suggest, in their own turn, that somewhere very far back in our ancestry, a bacterial consortium might fill the Holy Grail of our multicellular origins.
"Has thou walked in the recesses of the depth?" evokes the question of the origins of these depths and the multiplicity of their dimensionality. Tracking backward along the stream of time, there remains much, in our ancestry, to unravel; for as the meek would inherit the earth so perhaps the meekest of them all (ie bacterial consortia) have already come to inherit our bodies. These minute structures suggest that 90% of the cells in our bodies are bacterial in origin, and so it may be said that we are an indulgence for the 10% of the cells which are comprised of the bits and pieces over which we claim "true" sovereignty. The majority are ignored except when they fall out of line and become parasites again. With such grace have we failed to recognize these microbial minions - which we feed in our intestines the food before even "we" get to assimilate portions of it into our blood. Within and outside of our bodies there is a universe to explore, within which we singularly or collectively as a species are but minor spectators. It is a strange, haunting, and a stirring message - never quite driven home... until now.
As we entered the Grand Banks, we were fully prepared for the Titanic to bring us back nearly a century in time; but not 30 million centuries. As the storm in the desert taught Job: Nature is full of surprises.
THE HAMMER OF GODDuring the early morning hours of April 15, 1912, the Royal Mail Steamer Titanic, after challenging an iceberg, settled bow first into the ocean, snapped in two, and burst down towards the seafloor as a mighty death cloud. Were the waters truly transparent, and were it possible to step back ten miles and take a grandstand undersea view, the Titanic's death cloud, in both it's shape and expanding dimensions, would have seemed to anticipate, by several decades, the aerial debris field produced by the explosion of the space shuttle Challenger. Huge pieces fell out of the cloud, trailing long streamers of coal and dust and debris during their two-and-a half mile free-fall. The stern section was approximately 330 feet in length when it separated from the bow. When it struck bottom, with the sides blown open, and its decks compressing, coal, kitchenwares, shattered glass, luggage, fittings, and steel beams were coughed out of their respective compartments. Crashing down separately, within a quarter mile radius of the stern, boilers, and a mountain of piping and deck plating more than forty feet across, sent forth their own jets of deep sea ooze, ancient clays, and artifacts. Sheets and billows of crater ejecta radiated from multiple impact points. Artifacts from the stern were therefore interred in a system of ejecta blankets, the very same structures normally associated with the high speed impacts of meteorites.
By comparison, the bow of the RMS Titanic "parachuted" to the seafloor, coming to rest almost as she was docked: the hull upright, the decks level and the anchors ready to deploy. Behind spread the debris field and, in the center of the fields, three quarters of a mile away, lay the stern - now with it's propellers pointing towards the bow.
AN UNUSUAL PROCESSAs the dust clouds settled and the final ejected debris came to rest, the rebirth of the Titanic began. Within hours nature initiated the reclamation of humanity's symbol of dominance over nature. The ubiquitous microflora of the oceans arrived to join the microbes that were already aboard - and still very much alive. Bacteria have far more resilience to pressure changes than other living organisms. For example, homogenization of milk involves the application of a short term high pressure impulse of as much as 8,000 pounds per square inch. Bacteria in the milk being homogenized are able to comfortably survive that impact and so the predicted maximum of 7,500 pounds per square foot impact on the Titanic (or a shift from a sea level pressure of 15 p.s.i. to 6,000 p.s.i. at a depth of 2.4 miles) would appear to be less significant. Many of the resident microorganisms were either actively growing within the ship's existing systems (such as the sewage collection and holding tanks) or were introduced as passive migrants (such as dormant spores, or ultramicrobacteria). The initial microbial inputs would have come from the disturbed sea floor. Additional invaders would have arrived as residents in the biocolloidal particles which are a part of the "sea snow" which is often seen falling onto the Titanic. While the environmental conditions would seem, to human minds, too harsh to allow aggressive growth, they are to those invading incumbents quite "normal" and the question then posed is where to grow and what to grow on?
The Titanic once it had settled on the plain, provided a wide range of habitats for microbial invasion. Initial sites would have been where there was a relatively easy supply of organic nutrients. The bulk of the organics were cellulosic materials ranging from the decking to wall panels, cottons and paper with the remainder dominated by stored food supplies and the ship's sewage. The degradation of this material would have proceeded at different rates with the decking being the most recalcitrant (least degradable). Beyond the organics was the bulk mass of the hull itself, intact in some places and embrittled and sheared in others. In the hull, the dominant element is iron. When descending down a water well (rather than a column of seawater), the bacteria which so often dominate these environments accumulate so much iron that they can actually clog the well and/or corrode well fittings and steel casings. Ultimately, the system looses its production capacity and fails. These bacteria are known as the iron related bacteria (IRB) and can accumulate iron to as much as 10 to 40% of the dried weight of the clog "slime". The function of this accumulated iron in the IRB is a subject for debate but clearly the iron plays a protective role to the incumbent bacteria in the clogged zone of the well. In many ways the Titanic can be viewed rather like a steel cased water well with perhaps one very obvious and major difference: the water well has a liquid water column on the inside and an aquifer outside while the Titanic has an extremely large water column on the outside (the North Atlantic Ocean) and closeted volumes of water on the inside.
When a TV camera is lowered down a water well to monitor its condition, very often IRB and other bacteria can be seen growing within the water and in clog structures on the walls. When cameras are taken down to the Titanic, similar growths, performing similar functions, are seen on the outside of the hull. The most obvious presence of the this biological activity are the growths commonly referred to as "rusticles" (a name derived from a tendency for the Titanic's bacterial mats to hang down like icicles that have gone rusty). The earliest photographs of the Titanic's rusticles date from 1985, so the first seven decades of the ship's return to it's origins (bacterially derived iron ore) went unrecorded. However, it is now becoming clear that the rusticles preserve their history in an archeological sense and that all the elements of biological activity that occurred during those "lost" years can be pieced together.
Today, the hull plates literally "drip" iron and bacterial "sludge". On the bow, the outgrowths can be seen as plate-like blisters spreading horizontally along the promenade deck, or as whorls of concentric growths clinging like barnacles to the side plates, or as rivulets spreading away from the hull to become vast, rust-colored, and often fan-shaped outflows, taking the iron mined from the Titanic with them. As the outflows seeped into the sediments, acting as binding agents, something wonderful began to form: archeological oddities known as concretions.
During the 1996 expedition (sponsored in part by the RMS Titanic, Inc and the Discovery Channel), two hull fragments, each measuring approximately three feet across, were brought up from the debris field and placed aboard the research vessel Ocean Voyager. Bacterial outflows, apparently radiating from a larger source of iron nearby, had partially coated (as concretions) the steel plates, entrapping them - along with the sediment that surrounded them, and any debris that lay on and under them - forming a naturally occurring concrete (hence the name, concretion).
When the concretions were removed and examined, it was evident that the entrapped materials, including the two hull fragments themselves, were actually part of an ejecta blanket. The concretions were studded with fragments of coal, shards of glass and nuggets of clay. What we found were archeological cross- sections through the uppermost layers of the Titanic debris field. Descending through these concretious growths with a scalpel and a paintbrush was rather like turning the pages of a very old and brittle book. But within those "pages" were frozen, archeological signatures of events that occurred before, during, and after the Titanic's arrival; a rare bonus, when one considers that most deep ocean archeological sites would have to be frozen in situ and then moved to a holding tank for such dissection to be made possible. The Xerad design, for example, calls for the experimental freezing of a 400 year-old Portuguese carrack along with the sediment surrounding it. The frozen mass will be lifted one quarter mile to the surface of the Atlantic ocean, and the entire archeological site must then be moved to a large water tank and thawed for excavation, with museum visitors able to watch the procedures.
Within the Titanic's concretions, events are stacked layer upon layer, each recording a different chapter in a sequence descending backwards through time. The youngest, uppermost layer is covered with pieces of gravel (generally a quarter of an inch in diameter or smaller), reminding us of a slow but never ending deep- ocean hailstorm, manifested as the release of stones from all the melting icebergs that paraded over the Titanic site between 1912 and 1996.
Immediately beneath the gravel layer lies a second bed of rubble that appears, by volume, to be comprised of approximately 60% ancient sea floor clays. Some of the clay nuggets reveal, in cross section, layers or strata, indicating that they were once part of a local bedding plane deposited by the slow accumulation of organic matter known as "sea snow". The relative scarcity (or near absence) of glacially derived gravel in the nuggets suggests that the clays formed before the Grand Banks became a major pathway for melting icebergs. This would suggest that the clay beds in our concretion samples were laid down before the end of the last ice age, more than 12,000 years ago. Thus do the nuggets become clues to the violence of the Titanic's arrival on the bottom.
The accumulation of "sea snow" on the bow of the Titanic, and also on the tops of rusticles that have grown from the hull, broken away, and fallen to the seafloor; ranges in thicknesses from a quarter of an inch in most places, with occasional drifts up to four inches deep. To judge from this, it may be suggested that the pre-Holocene clay layer must lie at least several inches or as much as two feet below the present-day seafloor. It is probable, therefore, that the concretion-embedded clay nuggets originated from a shattered seafloor and were displaced from a substantial depth , at or near the stern's point of impact. Objects that have been found mixed in with the clays support rather than exclude this interpretation. Since these include bits of coal, shattered glass, and the sampled hull plates themselves, the blanket of sediment concreted to the plates appears to be composed primarily of shrapnel from the stern mingled with impact catapulted clays.
The observations in summary support the theory that portions of the Titanic reached terminal velocities high enough to create a downblast-outblast effect and form a multiplicity of ejecta blankets. Such forceful impacts with the seafloor would appear to explain the astonishing condition of the stern, which includes sheets of iron frozen in mid-shudder, like snapshots of leaves caught in a mighty storm.
The 1996 expedition to the Titanic clearly has implications for future expeditions. There is a need to pay more attention to the concretions, for they now appear to contain a fossilized sequence of disaster. In 1996, as the two steel plates were brought up to the surface, engineers, metallurgists and t.v. crews immediately removed the "crud" in an effort to facilitate rapid conservation of the remaining steel. This protocol called for cleaning off the rusticles and debris, washing in fresh water, submerging the plates in rubbing alcohol for four hours, air drying and coating with 10/30 motor oil, wrapping in 4 mil polyurethane film and sealing them with duct tape. Meanwhile, the rusticles and concretions, ignored as "wastage" by the metallurgists and engineers, became treasure to the biologists. As is often the route to exotic discovery, we found "the doors of the deepest darkness" hidden in the contents of the garbage pails and bilge.
RUSTICLE PARKA rusticle team has now been assembled and the research is coming along quite nicely, we are glad to report - with each question answered promising to become an infinite diverging regress of new questions. As we write, the rusticle garden flourishes down there, shadowy and silent, 2.4 miles under the sea, taking up the iron from the Titanic while festooning its decks, clinging to the hull and infiltrating every nook and cranny in the shattered ship. At St. Mary's University in Halifax, Dr Henrietta Mann has begun to identify what appear to be twenty different species of bacteria in the Titanic's rusticles, and two fungal species, and also members of the Archaea. These microbial groups were not spread uniformally throughout the rusticles but were cloistered in communities (consortia) strewn through the rusticle matrix.
Though bacteria-like in appearance, the last group, the Archaea, is now recognized as a class of life all its own. It is commonly associated with extreme environments such as undersea volcanic vents, very salty waters and highly reductive sulfide rich habitats. In the rusticles, the Archaea appear to have entered into a symbiotic linkage with other microorganisms. The form and function of the rusticles is now under intense scrutiny because they appear to be a new doorway through which we can see, at a distance, our own multicellular origins. They are not a single species of plant or an animal but a complex polymorphic (many shaped) consortium dominated by microorganisms, each performing some specific but essential function for the ongoing functioning of the rusticle.
Aboard the Ocean Voyager, the recovered hull plates were of great (biological) interest since they appeared to be the "dinner table" upon which the rusticles were growing, and from which iron was the main course. The plates were originally manufactured as strips of hot iron, rolled, re-rolled, and re-pressed in much the same way as the best Japanese swords were strengthened by refolding and hammering while the metal was still hot. This process produces subtle layers resembling the lines of cleavage in a crystal. On the Titanic there is evidence that these fine crystalline interfaces have become focused sites for covert intrusions and the expansion of rusticle growth. After entry into the steel plating, the microbes cleave the steel like a biological wedge, forcing the layers apart at each cleavage, essentially doubling the surface area available for growth. Many of the rusticles that were "washed" from the hull plates had a thick skin of metal (up to 0.12" thick) still attached to their bases, and their interiors often contained sheets from other layers, displaying a fractured series of biological wedges. As the rusticles penetrated into the steel, there occurred a gradual increase in the ratio of surface area relative to volume (via microbially induced cleavage and cavity growth). This is probably a major cause for the acceleration of rusticle growth (and the associated deterioration of the Titanic itself) observed by repeat dives to the site since the first robotic reconnaissance in 1985.
Identifying which microbes are involved and theorizing about how they manage to "digest" steel is not the stuff of passion. The real excitement here is in the unexpected door that has been thrown wide open, providing a view of the deep wilderness that reaches far beyond the Titanic - perhaps 3 billion years beyond to the first consortial life forms, things that became us.
Today at the University of Regina, rusticles are being grown on mild steel ingots, where they have begun to form complex attachment sites. Their growth has implications both in terms of the basic conditions under which consortial growth can occur, and for applications in corrosion control and the operation of systems in marine locations or even water wells. Essentially, a new branch of science is being born. During the first decade after the discovery of the Titanic, robot telepresence and submarine "fly- bys" with video camera logging had led most observers to view the rusticles simply as nuisance mineral formations of little note (rather like the stalactites in caves). When rusticles were finally recovered, observed, dissected, analyzed and cultured in 1996, a new, remarkably durable and robust form of life revealed itself at a site where most humans would think life could hardly exist let alone thrive.
And strangest of all is to peer into the heart of a rusticle, and to recall that for eleven years, in virtually every photograph of the wreck site, these "creatures" were staring us straight in the nose. Each rusticle is a complex assemblage of structures displaying many characteristics normally associated with tissue differentiation in higher organisms. Each displays a series of microbial consortia dominated by bacteria and fungi - which are, in essence, independent free-living cells grouped into differentiable structures. Included among these structures are internal water channels, water reservoirs, hardened iron-rich plates, surface ducts which pass through the external hardened plates and connect the rusticle interior to the outside environment, porous sponge-or- pumice-like layers, bundled fibrillar clumps and elegant thread- like "girders" which appear to be strung through the structures and channels and apparently provide a measure of mechanical stability to the entire rusticle.
On the Titanic, many rusticles reach lengths of ten feet, while others are but a few inches long. They all posses water channels, and typically they produce a central channel when the rusticle is hanging down. This central channel connects to water reservoirs, is surrounded by sac-like extensions, and is usually tied to other channels that meander through the "soma" (the body of an organism as distinct from its reproductive cells) to the surface ducts. The movement of water (along with nutrients and iron) through these structures is still a subject of speculation. The rusticles, which have been grown by injecting a modified Winogradski's culture medium (used to grow the IRB), produce a continuous supply of carbon dioxide gas, which flows out of the surface ducts when the rusticle is disturbed. This raises the possibility that the rusticle moves water through the "soma" by a pneumovective process (the carbon dioxide gas, even when dissolved under high pressure, forces the water through the channels through changes in the surface tension generated in the water). Another possibility is that water movement is simply gravity fed. In this case, water made heavy with dissolved iron descends through the rusticle, and after its iron is absorbed by microorganisms and incorporated into the structure of the rusticle itself, the lighter, iron depleted water is either circulated up again or ejected by the continually descending stream of iron-enriched water. Gravity assisted convection and pneumo-convection, along with one or two other processes we have not discovered yet, may be working together to form a primitive circulatory system.
The rusticles themselves vary from very delicate to very robust, depending upon location and age. The hanging appendage of the rusticle tends to be delicate and easily collapses even when lightly touched with the robotic hand of the Nautile. Other parts are exceedingly durable, and retain their shape even when they are removed from the seawater environment and slowly dried out. The fragile rusticle appendages (or anchor points) will often collapse while being examined in the laboratory. They have the consistency of a soft chocolate covered candy bar.
One feature common to all rusticles is a system of bacterially-derived threads, which line or crosshatch the channels, plates and reservoirs. They appear to bind the whole structure together into something that can be thought of as a "woven sock of slime". Some of the threads have been found to be very durable. They have even survived the partial collapse of the rusticle structure, dissection, microscopic examination, transportation, drying and storage.
Chemical analysis of the rusticles has revealed the iron content to lie generally between 20 and 35% (dry weight). The state of the underlying steel plates would suggest that the iron has , by and large, been "harvested" from the steel. Given that the density of the rusticles is high (between 1.2 and 1.8), that they have a high porosity and extensive internal surface area (projected from current studies at two-thirds the internal surface area of granulated activated charcoal), current estimates of rusticle mass on and in the bow of the Titanic easily exceed 650 tons. The nature of rusticle growth deep within the hull has not yet been addressed due to the lack of direct information. Clearly iron is being harvested from the Titanic by the biomass, sometimes referred to affectionately as "the Rusticle Park". The only available estimates of iron removal relate to the direct removal of iron from points where rusticles have directly attached to the plating and have generated extensive leg structures. Estimates here are that an average of 4 to 5 mm of the steel would have been pitted by the removal of iron. To continue this study, a much more precise understanding of the growth rate of the rusticles in their various forms needs to be obtained but already the losses of iron from the bow can be measured on a percentile scale with a possible range of extraction varying (from one steel plate to another) between 1 and 20% of the iron available in the steel. Biodeterioration is gradually weakening plates and beams so that the collapse of the decks and hull now seems inevitable, leaving only to the singular question of "When?" As deep ocean microbes convert the Titanic's mass to their own, it becomes possible to say that something is indeed coming to life on the Titanic; and it is the Titanic itself.
Paleontology teaches us that most of the world's iron ores were precipitated out of the oceans by bacteria. Humans took iron ore and created the steel that was the Titanic and now rusticles will take the iron out of the steel until the Titanic is no more. Ultimately the rusticles will die and leave the iron behind as iron ore. The cycle complete. Marcus Aurelius Antonius, in the second Century A.D., in his meditations considered "substance is like a river in a constant flow, and the activities of things are in constant change, and... causes work in infinite varieties; and there is hardly anything that stands still". So it is with the Titanic, the iron created and crafted by humans is now being reworked into a part of the "biomass tree" dominated by rusticles and the concretions of the deep.
Dissolution proceeds so quickly, now, that we suspect something in the deep ocean environment is speeding up rusticle growth - something other than the Titanic's iron and sulfur.
When visiting the Titanic on August 16, 1996 in the submersible Nautile, there had been a heavy "sea snow" falling and the rusticles were covered with a white fluffy dusting. If, as Henrietta Mann has suggested, rusticles are able to metabolize dead diatoms and other nutrients found in "sea snow", then increased rates of rusticle growth may be, at least in part, due to human intervention. A comparison of 1996 film footage with that obtained during the 1986 and 1987 expeditions reveals, in addition to a surge of rusticle growth, an approximately four-fold increase in the "snowfall" and a continuing increase in the population of bottom-dwelling invertebrate fauna (the latter sustained apparently by increased growth at the base of the food chain [that is, bacteria] owing to an increased fall of nutrients).
We attribute the increased snowfall to two activities: (A) overfishing in the Grand Banks region - which has, during the past decade, removed most of the fish that feed in the thick cloud decks of tiny organisms known as the Deep Scattering Layer, and (B) oil drilling - which, on the Grand Banks, has released methane-rich natural gas into the base of the Deep Scattering Layer's food chain (ie, bacteria).
The North Atlantic Deep Scattering Layer, to judge from the increased fall of "sea snow" seen at the Titanic, must now be thicker with microscopic life than ever before. One implication is that if the present ban on fishing continues to be enforced, then given this great abundance of food, fish stocks may recover quickly (in as little as a decade). Recovered fish populations will, in their own turn, thin the deep scattering layer again - which, in turn, will decrease the nutrient-rich snowfall, probably slowing rusticle growth and decreasing the rate of the Titanic's deterioration. As during her first and only voyage, the Titanic continues to be of nature, not above it. With such grace does the wreck site emerge as a useful and hitherto unanticipated monitoring station for the pulse of environmental degradation and recovery in the North Atlantic, for the liner's rate of deterioration appears to be directly related to the health of the waters above.
Two-and-a-half miles above the Titanic, we had no choice. When one floats in one spot on the ocean surface, rather than sailing through it, one witnesses changes not apparent to merchant seaman or QE2 passengers. Drifts of Sargasso weed come and go. Bioluminescent organisms rise to the surface after sunset, and go back down before sunrise. A reddish-brown lens of filth rises on the southern horizon and does not go away: the eastern U.S. smog layer - and we are 800 miles from New York.
One evening during the 1996 expedition, some crew members of the Ocean Voyager pointed out the tattered wreckage of a Japanese drift net floating among islands of Sargasso weed. Almost a quarter mile of it still remained visible. Years old, it was still killing everything in its path. Originally, it was fully twenty miles long, and if we saw one lost net, it seemed statistically impossible that it was the only lost one. If there were only five others, then at one point in time (for several years until they decayed) their accumulated length must have been 120 miles: a "wall of death" as long as Long Island, going round and round the North Atlantic, strip-mining the water of whales and cod and tuna - and anything else that got in its way. Is it any wonder that the long snowfall has become a blizzard?
We are living on a planet that is only 8,000 miles wide (that is, the "wall of death" times 66.6). The numbers roll easily off the tongue; but people do not readily grasp how small our planet is. No one and nothing can ever truly get lost on Earth.
Perhaps we can begin to answer, now, for Job; just a little bit. We have indeed come to comprehend the expanse of the Earth, to enter the springs of the sea and walk in the recesses of the depth. And, yes, it can truly be said that we have seen the doors of deepest darkness.
And we know.To judge from the size and shape of the ejecta blanket created by it's impact on the bottom (water-jetted debris are spread up to 300 feet in all directions), the stern had attained a terminal velocity up to 90 feet per second. It probably struck bottom within five minutes of losing its grip on the ocean surface. It sits, now, on the seafloor in twisted agony with many girders rippled, hull plates sheered and the deck railings ripped from their sockets.
The inertial forces exerted both above and within the stern can account for the ripping, sheering and hammering motions preserved (or fossilized) in its metal. The inertial forces from above would have been created by the funnel of water trailing behind the stern during it's descent. Water within the hull also carried a downward force generated by the speed of descent. When the stern reached the seafloor, and abruptly stopped descending, the accelerated mass of water continued to push towards the bottom and, finding it's pathway blocked, would have diverted outwards from the centre of the stern.
As a familiar and instructive gauge for the numbers surrounding the Titanic's final plunge, 6,000 to 7,500 pounds per square foot (four to five atmospheres, the estimated force of a column of water beating down between 55 and 70 miles per hour) is approximately equivalent to the atmospheric pressure on the surface of Venus, or roughly half the steam pressure generated by the Titanic's boilers. A mere fraction of this overpressure - two hundred pounds per square foot - would be sufficient to collapse the Golden Gate Bridge. The destructive power of the water jet beating down upon (and within) the Titanic lay in it's mass. A large bath full of water weighs three quarters of a ton, meaning that it takes only a stream of water two feet deep and seven feet wide to sweep a car away, even at a conservative 10 miles per hour. For the 90 foot by 330 foot stern section falling to the seafloor, the slipstream of displaced water would have had a descending force measurable in kilotons.
Water moving at tens of miles per hour, exerting a force of more than 1,000 pounds per square foot, can, for a small part of a second, become indistinguishable from steel. "Test Baker" (1946, 20.3 kiloton fission bomb detonated under 90 feet of water, to produce a tsunami) and other above ground detonations provide examples (or analogies) of how this can happen. At Bikini Atoll, 3,000 feet from "Test Baker", the velocity and force of the pressure wave was the same in the water and in the air - 10,800 pounds per square foot (5 atmospheres). In other words, the densities of air and water were, very briefly, indistinguishable. In the water and in the air, during an interval measured in milliseconds, sheet metal on airplanes rippled like the skin of a dolphin, then froze, "fossilizing" the ripples, as the shockwave passed. Similar "fossil shockwaves" can be seen in scraps of the Titanic's hull, and in the silver flatware ejected from the Titanic's stern. Under powerful shock-front or water-jet conditions, water can act like iron and iron (which is merely a super-cooled liquid) can act like water.
See Accompanying Diagrams: