Documentary Movie - Planet Earth - The Great Lakes

[Music] the greatest of all lakes have been called inland oceans freshwater seas their name depicts their grand size along their shores one can gaze on natural wonders and soaring man-made skyscrapers 34 million people who live near the water's edge call this home but no one has ever looked down into the depths of the lakes like we will only now can we reveal their hidden secrets we begin our exploration on lake superior the grandest of the lakes the largest deepest and most mysterious along the south shore of superior is pictured rocks national lakeshore named for the colorful cliffs that rise from the lake bottom it's one of the most spectacular locations on the great lakes but it isn't the scenery that makes this location important it is what lies offshore deep under the water that has never been seen before if we drain the water from lake superior just 40 kilometers out from pictured rocks what will we find [Music] [Music] we can reveal for the first time the hidden landscape of the deepest part of the great lakes basin nearly 400 meters down the height of the empire state building no one has ever been here no light penetrates to this depth it is truly an alien landscape most people have this idea that a lake is just a simple bathtub essentially and i like to think of it that it's it's basically a record of it records not only what's happening now but what's happened in the past you know it's essentially a fingerprint [Music] a record of the past read by nigel watrus who has studied this area extensively those valleys are pretty big that's such a contrast to other parts of the lake that you know it really makes you so sit up and think about you know the processes that develop that type of topography the processes that formed these valleys at the deepest part of superior occurred when ice ruled the land [Music] twenty thousand years ago if you look down from space you would have seen this a massive ice sheet covering this part of the world where the great lakes now exist this ice is believed to have been over one and a half kilometers thick in places it would have towered over cities like chicago and toronto for thousands of years this enormous ice sheet presses down reshaping the land gouging deep holes when the ice begins to melt and retreats these deep depressions fill up with cold glacial water the result the formation of today's great lakes fast forward to the present day we can reveal the evidence of the glaciers effect on superior's lake bed only because it's been surveyed in great detail modern technology gives us the ability to see through the water column nigel watrus and his team from the large lakes observatory in duluth use side scan sonar and multi-beam devices to map areas of lake superior [Music] since sound travels easily through water it can pierce the depths of even the deepest part of superior to uncover its shape and size in amazing detail [Music] the multi-beam data collected gives us the ability to recreate the deepest part of superior in life like realism at 400 meters down we can finally see how it formed ice plays a role but it's primarily acting as a as the cap and it's the water flowing underneath which is really carving those channels so water created these huge hidden valleys which run for many kilometers at the deepest part of lake superior the sheer weight of the glacier pressurized the melt water sand and rock particles in the high pressure streams carved through the bedrock shaping these long deep and wide valleys but is a window to the past further south we come across one of the most striking man-made features on the lakes a huge suspension bridge spans the straits of mackinaw between lake huron and lake michigan at over eight kilometers it is the longest bridge in the western hemisphere once a year on labor day the public are allowed to walk over the mighty bridge to marvel at this engineering achievement the bridge spans are high and wide enough to offer safe passage to large cargo ships thousands of people take the opportunity to cross it on foot but few if any are aware of what lies below the surface if we drain the straits of mackinaw what will we discover [Music] [Applause] [Music] what the people can't see and the challenge for the bridge builders many years ago is a deep channel that snakes through the straits of mackinaw it's a 40 kilometer long 1 000 meter wide gorge that runs secretly right under the center of the bridge as we fly down the long hidden channel how did this get here is this evidence that the great lakes were not always as they appear today what occurred many years ago to create this extraordinary feature the answer could lie with expeditions further to the south on lake huron expeditions that will find incredible evidence of submerged waterfalls as large as the present day niagara falls and with them more revelations of the great lakes past when we drain the waters from the straits of mackinaw between lake huron and lake michigan we uncover evidence of a hidden gorge under the massive bridge how and when it was formed is a mystery that we may solve when we venture further south to the center point of the great lakes basin on the tip of the bruce peninsula located here is the town of tobermory ontario this spectacular area holds many clues to the geological history of the great lakes high atop the surrounding cliffs there is evidence from over ten thousand years ago of incredibly high water levels the result of a sudden increase in the amount of water from melting glaciers the scars of water erosion cutting into the rock face are evidence of this dynamic post glacial period these high water marks of an ancient shoreline are easy to see but what is not visible we can find offshore hidden under the surface of the lake topo mori region is quite unique in the fact that a tremendous number of features exist on the lake bed that tell you all about its history the history of water levels going up and down you can actually find most of the history as to how the great lakes drained by studying the lake bed here in the tobermory region the idea that water levels have fluctuated wildly has excited some of the lake's leading researchers it opens a window onto the past and could give clues to the future we have some preliminary maps of the lake bed here and we're looking for early evidence that the lakes drained about at least 50 meters below the present elevation now nobody ever thought great lakes water levels went that low but we've learned that they did starting around 10 000 years ago the climate was more arid and lake levels dropped because of evaporation and they eventually got very low such that georgian bay was an isolated basin [Music] but it's been nearly impossible finding the evidence of lower water levels since all traces have been hidden under hundreds of meters of water for over six millennia now modern technology has opened up a virtual looking glass the canadian hydrographic service boat is equipped with multi-beam technology a device on the hull of the boat bounces sound waves of objects on the lake bottom building a map of the underwater terrain for the first time we can actually see the lake bed in very high resolution the lake bed gives up more clues to a markedly different person the channel actually drops to a depth of about from 30 to 50 meters the biggest thrills for a geologist is to be able to actually see something in the three dimensions we can move around uh we can actually look at all sides of the channel like see where the water actually flowed over the top of the escarpment and then i can actually see the plunge pool at the bottom using this new data what will it look like when we drain the water off the bruce peninsula if you've been here 7 500 years ago the water here would have been totally drained the escarpment would have been exposed and we had river flowing from the north to the south here it actually turned to the east at this location and then flowed to the east and over the escarpment to form the dunks point waterfall further mapping reveals that more river channels and more waterfalls some larger than niagara falls existed off the bruce peninsula eight thousand years ago seven thousand to eight thousand years ago you would have seen each lake as a separate basin with few if any rivers running between them the gorge under the spans of the bridge in the straits of mackinaw formed when lake levels were much lower it was then a narrow river joining huron and michigan the low water level existed long enough to cut and gouge the lake bed leaving behind this evidence of an ancient river channel the geology of the great lakes is so recent that these events could have occurred when humans lived in north america is there any evidence of early man's presence at the time of low water levels the answer may lie 80 kilometers to the southwest of toba mori in the middle of lake huron another striking feature rises off the lake bed when we drain the second largest of the great lakes the alpena amberley ridge it extends across the entire lake seven thousand to eight thousand years ago it was dry land [Music] it's this massive limestone outcrop that resisted the ice sheets and it exists on the bottom as a very striking column scarp of sheer rock that on the northeast side drops away hundreds of feet so it's it's a very striking feature now and it would have been even more striking when it was above water as this land bridge was exposed during the very years that early paleo-americans roamed the continent could they have lived and hunted here and after all this time could anything underwater still show signs of their presence historical point of view it's important not just because of the sites themselves but because they present an opportunity that we'd never have on land in the sense that the sites are pretty much left just the way the hunters left them it's like a pompei underwater really using an rov a remotely operated vehicle john o'shea and his university of michigan team have searched the lake bed for anything that might suggest the presence of humans on the ridge [Music] what we found to date are a series of stone constructions that are very similar to stone constructions that are made by modern caribou hunters in the canadian arctic by taking john's research we can build a picture of the top of the ridge it's only when we drain the lake that we can see the line in all its entirety are these caribou lines the hunting technique that relies on the animal's habit of following linear features in the landscape could these stone constructions be just such a device to help funnel caribou into killing zones so far john and his team have been limited to rov research [Music] in order to actually bring home the bacon and prove that we have the archaeological sites prove that we have the artifact nothing to be done other than to put archaeologically trained divers on the bottom and have them systematically do this search john gets his wish divers descend the waters of lake huron to explore the lake bed could they be the first people on the alpena amberley ridge in over 7 000 years 80 kilometers out in the middle of lake huron divers descend for the first time on this part of the ridge they may be the first humans here for over 7 000 years [Music] it's like it's like watching the moonshot it's like watching neil armstrong these images support john o'shea's initial belief that prehistoric hunters could have laid lines of rocks to corral caribou this starts the main blind off on that direction so we're really kind of looking at this thing almost from the direction of caribou looking the divers begin to document and study this unique underwater landscape literally any handful that you lift up could in fact have have material on it so every one of these is sort of pregnant with the with the potential and you just kind of watch it from here on the video and sort of say okay i want to see that [Music] the divers have 45 minutes of bottom time to gather as much evidence from the lake bed as possible the expedition proves fruitful there are countless samples for the team to study and analyze a tiny sharp edged stone offers immediate hope that definitely looks like a bulb there this would be typically a kind of a flake this size would be a a bi-faced trimming flake a kind of tertiary flake where you're where you're modifying the edge you're finding up or you may you might do it when you're re-sharpening or modifying a tool and that that's honestly why it is what is so very small and remember i told you this the smallest humblest little piece this may be the smallest humblest little piece but we'll take it it may take many more expeditions and detailed explorations on the surface of the ridge before the truth about man's presence can be confirmed but the lake bed is giving up secrets evidence of the extreme low water levels from thousands of years ago are being revealed as we drain the lakes [Music] further south water flows from huron to the shallowest of the great lakes lake erie on the north shore we look down upon a geological wonder a land formation that extends over 40 kilometers into the middle of the lake it's made entirely of sand a byproduct of glacial ice grinding away at the bedrock this feature is fittingly named long point in terms of the great lakes system uh long point is almost unique it's not unique in the processes that formed it it's unique in its size and the scale of what's going on what's going on simply put this colossal sand feature is being created in lake erie at a geologically high rate of speed about five thousand years ago we probably would be standing in water because long point did not exist at that time long point is built out into the deepest basin of lake erie to a depth of about 65 meters so it's taken a tremendous amount of sand to build this thing up all the way to the surface troy holcomb headed up the team that created the first detailed bathymetric map depicting water depth of lake erie when he worked with noaa the national oceanic and atmospheric administration [Music] this is the data we use to drain lake [Music] erie [Music] as the water level drops we see two massive sand ridges long point escarpment and clear creek ridge hidden from view until now both of these ancient sand ridges almost bridge the lake they were built by huge glacial sand deposits and formed when the water was much lower the sand ridges that you see on the floor of lake erie would be very similar in their relief and topography to the long point feature that we see today creating these massive sand ridges not only takes an enormous amount of raw material but also the right combination of the forces of nature the thing that makes it unique the fact that you have such a prolific sand supply in the shore west of here only 20 kilometers west of longpoint are these sand cliffs laid down by waters receding after the ice melted these cliffs feed long point and probably helped build up the ancient ridges a process of sand redistribution that has been going on ever since the glaciers retreated and continues to this day today we saw geological processes at work moving sand around right as we were there this area is eroding away very fast you can see mud and sand in the water the wind is from the southwest and so the long shore drift the sand is going to be to the east eventually it will make its way all the way out to the end of long point you sort of see the dynamics of all the sedimentation that's going on here and it's happening now and it's happening fast [Music] ancient sand ridges and present day long point all created by the same force of shifting sands through wind and water as we drain the great lakes we notice how these lakes change and evolve as water levels fluctuate the lake beds are truly ever-changing landscapes downstream from lake erie is one place where there would have been the most dramatic change of all probably the most spectacular landmark in the great lakes system niagara falls in a single minute over 135 million liters of water flow over the falls into the raging niagara gorge all the water in the great lakes basin travels through this narrow corridor the power and force of the water continually cuts back the gorge since the retreat of the glaciers the falls have moved upstream from lake ontario closer to lake erie by just over 11 and a half kilometers as the constant stream of water erodes cuts and creates the gorge but during the time man might have walked on the alpena ridge and the waterfalls existed in the tobermory area niagara's raw fell silent if we drain niagara falls as they were five thousand to ten thousand years ago this is what we would see the raging niagara river becomes a trickle and for a period of several thousand years the falls dry up with all the upper lakes being separate basins little water flows between erie and ontario mighty niagara was not so mighty downstream from the falls is lake ontario draining this lake reveals striking clues to a turbulent past and an uncertain future [Music] five thousand years ago the water starts to rise throughout the great lakes a tropical air mass settles over the great lakes basin and precipitation fills the lakes to present day levels niagara begins to flow long point starts to form and in lake ontario something unusual is happening on the lake bed toronto is the largest canadian city on the great lakes two and a half million people live and work near the lake ontario shoreline it's a city that has been known to be geologically stable but not far from the towering skyline of the city something dramatic is occurring on the lake bed the discovery of long ridges laden with cracks crisscrossing the lake bottom [Music] what happened is that north america is under pressure would you believe that the area to the northeast like greenland is pushing to the southwest the area around california is pushing to the northeast so it puts the great lakes region under pressure and what happens under pressure is that the earth pushes up these ridges have a simple name pop-ups the pop-ups are a demonstration of the fact that earthquakes are occurring in the region and will continue to occur we don't normally associate the great lakes region with earthquakes but the lake bed is showing signs that seismic activity may be more frequent than we think it was only since the advent of multibeam we could actually clearly understand this network of cracks and fractures that have been thrown up into bedrock ridges these uh long ridge-like features are are pop tectonic pop-ups and what they are is is compressional fractures in the rock like this piece of paper the limestone here has compressed and you started pushing on it from either direction it would fold up in the middle so this is how a pop-up is formed what they tell us is that the lake isn't uh isn't as geologically stable as we were led to believe taking this detailed multi-beam data we will drain lake ontario near toronto harbour and see for ourselves what is on the lake bed the number of interconnected pop-ups is staggering they are one to three meters high between five to ten meters wide and can run for many kilometers along the lake bed no one knows for sure how old they are but with this evidence of seismic activity what does the future hold for this part of the great lakes the history in southern ontario is very low amplitude earthquakes we have lots of very very small ones will there be big events in the future that need to be taken into account we don't think so but that research is needed to make sure we build structures strong enough to withstand the anticipated largest earthquake or the largest force that will be placed on these structures draining lake ontario doesn't only reveal a possible future it also gives a glimpse of a turbulent past at the eastern end of the lake near its exit into the saint lawrence river a mysterious and strange feature lies just below the surface this is charity shoal nearly 20 kilometers offshore right on the u.s canadian border recent depth surveys reveal a circular anomaly but its origins are a mystery today charity show will be multi-beamed in detail for the very first time as the boat moves back and forth over the shoal the feature begins to take form a crater-like image is revealed but what is a crater doing in the great lakes troy holcomb from texas university a m has been interested in this feature for years now he wants to solve the mystery of charity show from what we've seen charity show is a very old feature that has been re-excavated by glacial erosion it still looks very possible that this is an impact crater an extraterrestrial impact but it's remaining to be confirmed to investigate further where the charity shoal is indeed the result of a meteorite strike what better place to study than the best preserved impact crater in the world barringer crater located outside of flagstaff arizona i don't think there's any place in the world where you could go and get a better comparison for what we're seeing at charity show yeah that does look absolutely amazing you really get a feel for its size barringer crater seems to be frozen in time looking like it did fifty thousand years ago when a meteor traveling at over forty thousand kilometers per hour slammed into the earth did charity show ever look like this on charity show we're seeing ridges that look like the exposed edges of bedrock at the top of the rim just like you have here only eroded in the case of charity shoal both craters are nearly round and have a continuous rim they're both about 1.2 kilometers in rim to rim diameter and this is an important feature because it means that both craters if charity shoal is indeed an impact crater it means that both craters would have experienced about the same projectile coming in and in the same size of explosion like barringer crater a meteorite 50 meters in diameter could have plunged into the primeval ontario countryside a 10 to 20 megaton explosion could have created charity show [Music] when we drain charity show we see the similarities but it has gone through at least four glaciations and has been underwater for thousands of years it's a shadow of its former self but just maybe millions of years ago if you stood on the rim of charity shoal it would have looked like a this strike is not the only dramatic event to impact the lakes region violent storms lash these inland seas sending ships into the depths we reveal some of the most dramatic evidence of nature's ferocity as we continue to drain the great lakes when we drain the great lakes part of our own history will be revealed scattered across the lake beds shipwrecks nearly 6 000 spread out over five great lakes metal and wooden relics hidden under the surface of the water that we can now see in all their glory some are still majestic and upright others torn twisted and broken up the shipwrecks are some of the most impressive sights to behold when we drain the great lakes [Music] the large number of shipwrecks in the great lakes really speaks to the volume of shipping that was happening so for a couple hundred years when there's this really intense um shipping going on in the great lakes in the late 18th and 19th and early 20th century when this was the busiest waterway on earth russ green works at noaa's thunder bay national marine sanctuary on the shores of lake huron here like many areas on the great lakes numerous shipwrecks scatter the lake bed lakes is a misnomer i mean this is the largest fresh water system on earth they are massive they're treacherous tough places to be if you're in a 130 foot schooner in the 1870s in november the driving rain freezing caking onto your rigging they're dangerous places to ship fire storm fog shoal human era no radar no gps lots of collisions just off here in thunder bay all of these things contribute it's the volume and the hazards contribute to why we have so many shipwrecks [Music] when we look down onto the shipwrecks another story emerges the most recent and maybe most shocking of all alien species not native to the lake system mussels have infiltrated all the lakes even parts of lake superior in the 1980s they arrived by ocean-going vessels unknowingly transporting them in their ballast tanks and within a 20-year span they are reproducing at extreme rates and changing the complete biophysical makeup of the great lakes probably right now lake michigan has the highest populations of mussel populations followed probably by lake ontario lake erie and then lake huron and lake michigan just seems to be perfect setting for the population growth of mussels has high calcium concentrations and high availability of good food for them the northeast sector of lake michigan the manitou passage is a stunning area above the water as the sand cliffs of sleeping bear dunes national lakeshore tower over the passage that was once a major shipping route [Music] but under the water things are changing rapidly with the onslaught of the muscles divers prepare to dive a wreck off the shores of south manitou island the wreck is called three brothers famous for being buried for most of the last century under sand until a decade ago when shifting sands revealed it again to the world unfortunately the ship is now a shocking example of the true effect of the mussels a form of algae known as cladophora is growing at a phenomenal rate as the mussels clarify the water sunlight penetrates deeper into the lake resulting in explosive algal growth this cladophora is dying and collecting in a thick decaying mass near the wreck the dead algae releases toxins fatal to fish and birds here in the manitou passage an environmental meltdown is underway as we drain the manito passage how many more areas are like this on lake michigan and the rest of the great lakes and is this the first stage of the end of the great lakes as we know them i don't think i would ever doom our lakes we've been here for several thousand years and there's many thousand years to come our ecosystem is undergoing a severe challenge the changes that have occurred in the last 20 30 years are dramatic the lakes are strong enough it's just what is the new ecosystem and how will that new ecosystem evolve and how will we interact with it there are many legendary great lakes stories but non-so captivating as the most iconic of them all the sinking of the edmund fitzgerald as we drain the great lakes we have uncovered dramatic evidence of a rich and varied past both natural and man-made and geological wonders hidden from view these inland seas were the highway into the continent the trail of wreckage proving the lakes were always in control nowhere more so than the largest of them all lake superior with the deepest water and the mightiest storms it is a test for the most modern of ships on the south shore whitefish point is known as the graveyard of shipwrecks one particular wreck 27 kilometers offshore has taken on legendary status no doubt the the iconic shipwreck of all the 6000 have gone down in the great lakes is the 1975 loss of the edmund fitzgerald the edmund fitzgerald the largest ship to have sunk on the great lakes when we drain the water out of lake superior we can see this mighty ship as never before it was probably the worst storm in three decades that claimed the edmund fitzgerald [Music] it sunk in 535 feet of water without a single cry for help and it took 29 men to the bottom with it still remaining with the ship to this day tom farnquist knows the wreck of the fitzgerald all too well he has led three expeditions to the watery grave and is one of the few people who have seen it firsthand our exploration of the edmund fitzgerald revealed a ship badly damaged it was ripped in half the forward section which is about 200 plus feet long is sitting almost on an even keel the stern twisted off and fell upside down based on side scan sonar data these images show how the edmund fitzgerald sits on the lake bed 163 meters down the images speak to the intensity of the storm and how quickly she sank if you were to drain lake superior you would see the damage to the bottom caused by the impact of the ship the rest of the lake bottom looks like a moonscape quite smooth little potholes here and there but you get near the edmund fitzgerald it almost looked like a snow plow had gone along and pushed the clay up on either side of the fitzgerald it literally plowed its way into the bottom maritime experts naval architects suggest that the fitzgerald hit the bottom about 35 miles an hour 27 feet down below the clay it hit bedrock and started coming apart this mountain of steel is in pretty good condition in some respects the paint is there it's very visible you can read the name on it so this moment in time is still well preserved by the cold deep waters of lake superior i've been on a lot of shipwrecks uh over a couple of decades but nothing as grabbing or as moving as the edmund fitzgerald knowing that 29 sailors in modern day went down in the shipwreck it's still the most mysterious of all the shipwrecks on the great lakes [Music] undisturbed and silent the edmund fitzgerald will haunt superior's lake bed for decades to come a reminder of the power and majesty of the largest freshwater system on earth a system whose secret underwater world is revealed for the first time when we drain the great lakes

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Keywords: documentales 2020, documentales de leones, documentales en español, documentales animales, documentales hd, documentales marinos, documentales del universo, documentary bbc, documentary animals, documentaries, documentary movie, documentary africa, documentary about space, documentary about life, documentary ancient, documentary america, documentary amazon

Id: o9qCJgD1zFQ

Length: 41min 49sec (2509 seconds)

Published: Fri Aug 28 2020