How this tiny Fish is Cooling our Planet

these are lanternfish although they don't look like it these tiny fish are maybe the most important fish in the ocean to understand why we have to go back roughly 100 years since the inception of echo-sounding at the start of the 20th century we picked up strange echoes from the depths of the ocean something deep below the surface appeared to reflect the sound produced by the sonars these echoes were often so strong and so widespread that they were thought to show sandbanks or the ocean floor even though later experiments revealed that this couldn't possibly be the case right from the start there was a considerable interest to understand these mysterious signals mainly because the us military feared that what would become known as the deep scattering layer could severely impair the ability of their newly developed sonars to detect hostile submarines or even allow them to hide in or below the layer completely a first breakthrough came in the late 40s when the team of biologists of the scripps institute of oceanography in collaboration with the university of california's division of war research could show that the layers seem to move up and down the water column depending on the time of day during the daytime the deep scattering layer was typically observed at depths of between 400 and 600 meters at dusk however it started to rise to the surface where it stayed during the night before descending back to deeper waters at dawn this pattern which repeated every day made animals the most likely source of these echoes since the challenger expedition a scientific expedition conducted by the british government during the 1870s for the purposes of exploring and studying the open ocean it had been known that certain animals from the twilight zone the part of the ocean that sits between the sunlit surface waters and the pitch black deep sea at depths of 200 to 1000 meters make considerable vertical migrations every night to feed in the rich waters near the surface before returning to the relative safety of the deep at dawn but just how spectacular and dramatic these so-called dial vertical migrations truly were was only revealed through the discovery of the deep scattering layer that animals could scatter sound was also not a new discovery ever since the 1930s echo sounders had been successfully used above known fishing grounds to identify schools of fish what however was surprising was the magnitude of this pattern these weren't distinct groups of animals but continuous layers layers that seemed to stretch without end for miles and hundreds of miles in every direction today we know that the deep scattering layer is although it varies in structure and severity depending on the region indeed a global phenomenon that stretches through every ocean and encompasses the entire planet the main culprit responsible for this mind-blowing phenomenon is as you probably guessed by now the lanternfish the ecosystem of the deep sea is complex rich in diversity and notoriously difficult to study we have sent more people into space than to the deepest parts of our oceans the twilight zone alone also known as the mesopelagic zone might hold as many as one million undiscovered species even after decades of research we still know very little about this alien world but with every piece of new information that is being discovered it becomes clear that this zone might be considerably more important to the ocean's ecosystem and even the entire planet as we have previously thought among the colorful group of animals that inhabit this zone one group dominates lanternfish this diverse family of around 250 species of tiny fish most of them smaller than your thumb is the most abundant fish found at these depths maybe even in the oceans altogether sampling by deep sea trawling indicates that lanternfish have a global distribution and make up as much as 65 of the deep sea fish biomass how many there are of them exactly is however still somewhat of a mystery one reason is that the fish of the mesopelagic seem to be extraordinarily good at avoiding incoming nets that are used to survey them like most fish lanternfish possess the ability to detect fine pressure changes in the water with a special sensory organ the lateral line system comprised of a series of canals that run along the side of the body the fish can detect low frequency vibrations produced by the movement of prey or predators sonar observations of ice lanternfish have shown that they are able to detect approaching predators and trawls at a range of 30 meters or 100 feet and more which indicates that their ability to detect these pressure changes is exceptionally well developed another tool they might use to avoid dangers is bioluminescence as their name suggests lanternfish have the ability to produce their own light using a set of tiny organs called photophores that are dotted across their head their flanks and their abdomen with these organs which use the same chemical reaction that is used by fireflies to create light the fish are able to produce anything from a dim glow to bright flashes lanternfish use this ability for a multitude of purposes such as to lure prey or attract potential mates to camouflage their silhouette against the light from above a process called counter illumination and to warn each other of nearby danger like an approaching net for instance another important thing to know about lanternfish is that they migrate not over great distances but instead vertically over great depths every evening the masses of lanternfish follow the advancing darkness up to shallower waters to feed on the abundance of zooplankton found near the surface to make these migrations easier lanternfish possess a gas-filled swim bladder that allows them to control their buoyancy these tiny inclusions of gas in the bodies of millions and tens of millions of tiny fish rising and descending through the water column during their dial vertical migrations are one of the main causes of the phenomenon of the deep scattering layer as they reflect the sound produced by the sonars particularly well although fairly unknown lanternfish are very important for the ocean's ecosystems and also for us humans they are a main food resource for many large predators that inhabit the open ocean such as sharks dolphins whales seabirds and other fish and are therefore also an essential prey for key fishery stocks like tunas mackerels and billfish but their importance for humans goes far beyond that the open ocean was long thought to be a watery desert that as opposed to the rich and productive coastal regions above the continental shelves where life is flourishing is mostly devoid of life and only inhabited by a few nomad species that roam the vast emptiness of the high seas in search of the occasional patches of productivity and while this might be true on the surface exploration of the deeper parts of the ocean has revealed an ecosystem of incredible abundance and diversity given that the mesopelagic comprises about 90 percent of the ocean's surface and 20 of its volume it is one of the largest ecosystems in the world and an enormous reservoir of unexploited resources extensive trawls conducted in the 1970s suggested that the fish biomass found in this zone might be as high as one billion tons or one gigaton for comparison the amount of fish caught each year by commercial fisheries worldwide is with a little under 100 million tons only roughly one tenth of that and that was before we understood how well mesopelagic fish avoid nets using global acoustic observations of the deep scattering layer and satellite measurements of the primary production recent estimates of the potential fish biomass were consequently revised upward significantly today most estimates put the number at somewhere between 5 and 10 gigatons that's the weight equivalent of somewhere between 120 to 250 billion people 30 times the current population most of the biomass is made up of lanternfish which means this single fish family outnumbers and outweighs all fish found in surface waters combined the daily migrations that they and many other inhabitants of the mesopelagic undertake are without a doubt one of the largest migrations in the animal kingdom a gigantic living wave consisting of jellyfish tiny crustaceans squids and countless species of fish that sweeps through our oceans every single day under the cover of darkness how important these migrations are we are just beginning to understand the ocean is by far the largest carbon reservoir on the planet and an important carbon sink that has absorbed an estimated 40 of all carbon produced by humanity since the industrial revolution most of the carbon that enters and leaves the oceans every year as part of the natural carbon cycle does so through simple physical and chemical processes however there is also a considerable amount of carbon that is moved by the so-called biological pump this mechanism describes the storage and redistribution of organic carbon in the ocean by the plants and animals that inhabit it as our understanding of these processes has increased over the last two to three decades it has become clear that this aspect of the carbon cycle was substantially underestimated in the past in a nutshell it works like this near the surface photosynthesizing organisms such as phytoplankton use the energy from the sun to convert inorganic carbon so co2 to organic carbon this primary production which amounts to roughly 100 gigatons of carbon per year fuels the entire ocean ecosystem from here the carbon enters the food chain first consumed by tiny crustaceans and other forms of zooplankton the herbivores of the ocean and then by a continuous number of larger and larger predators in this way the carbon is stored for months years and decades this process creates a lot of waste products such as detritus fecal matter dead cells and carcasses typically combined under the term marine snow most of this material is immediately used again by smaller or larger consumers but the portion that remains sinks to the deeper part of the ocean where it forms the basis of the food chain just like phytoplankton does near the surface that way the organic carbon that was produced near the surface is essentially being absorbed by the deep sea cycled in the food web respired and eventually converted back into dissolved inorganic carbon by microbes it can be trapped here for hundreds thousands and in some cases even millions of years this is how the biological pump removes carbon from the atmosphere but it's not the entire picture while marine snow is certainly the main transport mechanism of the carbon export to the deep sea our research of the mesopologic over the last few decades has revealed that the large community of animals that live here also play a significant role in this export process and therefore the global carbon cycle by consuming organic matter near the surface at night and bringing it down to the mesopelagic where it is excreted and respired during the day lanternfish and other organisms that undergo dial vertical migrations actively transport carbon into the deep ocean that otherwise would have remained near the surface for a long time through these migrations tens of millions of tons of food are exported to the deep ocean every night and with it enormous amounts of carbon assuming each fish consumes about 1.5 percent of its own body weight each day it would take the entire population of lanternfish just one week to consume the weight equivalent of the human population in food based on these numbers it shouldn't come as a surprise that new studies suggest the active transport by vertically migrating animals might be responsible for as much as one third of the carbon that is exported to the deep sea which is currently estimated to be around 11 gigatons per year this means the migrations of the mesopelagic community might remove the amount of carbon out of the atmosphere each year equal to half the carbon that we emit through our burning of fossil fuels of course all these numbers are only very rough estimates but they showcase why we need to study this part of the ocean it is an important gear in the global carbon cycle that is entirely driven by a community of animals that we still know very little about it is probably the most understudied part of the carbon cycle simply because of how difficult it is to study and this lack of knowledge could become very detrimental in the future while mesopelagic fisheries are currently still rare and those specialized on lanternfish even more so mostly due to significant technological and economical hurdles this could quickly change despite shrinking fish stocks the demand for marine protein is constantly rising which makes the large unexploited resources found deep in the ocean more and more attractive each year numerous experimental fisheries are currently being set up around the world and many more will likely follow our growing population and the worsening climate that already threatens farmland on a global scale make a large-scale exploitation of these untapped resources almost inevitable but this fish stock is unlike any other which makes the exploitation of this community a high-stakes game that if not done sustainably could have consequences that extend far beyond the surface of our ocean

Channel: Deep Dive

Views: 992,195

Keywords: Lanternfish, Lantern Fish, Fish, Ocean, Ocean Animals, Deep Sea, Deep Sea Creatures, Twilight Zone, Mysterious, Fascinating, biology, animals, science, climate, climate change, global warming, artic, polar, antartic, cooling the planet, Glacier, whale, documentary, animation, infographic, motiongraphic

Id: I8KpuydjfJI

Length: 14min 13sec (853 seconds)

Published: Thu Sep 17 2020

Reddit Comments

[u/FatboyChuggins]

This video was really fascinating. The ocean is so beautiful yet so unknown and kind of scary. I'm so eager to learn more about deep ocean exploration and stuff.

[u/Chamero]

I didn't think I'd watch the whole video yet here I am. It's fascinating to think about how much we just don't know about such a large part of our planet.

[u/nicethingyoucanthave]

Wait, I thought the cause of sonar reflection was the thermocline layer

[u/jesusThrow]

What did I just watch? Tiny youtube channel with two videos, and the video is mixing the concept of sonar thermal layers, with schooling fish, stating that these fish are a potential solution to global warming, as long as we don't attempt to over fish them. There's so many linked ecological topics here, it feels fishy. But interesting video if true.