English version below
Es beginnt der zweite Teil unserer Forschungsreise. Wir fahren im Moment Richtung Norden in die Labradorsee. Inzwischen ist es mit einer Lufttemperatur um 4°C richtig kalt geworden. Wir sind auf dem Weg zum 53. Breitengrad. Dort liegen fest verankerte Geräte, die zum Beispiel Temperatur, Salzgehalt, Sauerstoff und Strömungsgeschwindigkeiten messen können. Man kann sich das so vorstellen, dass die Messgeräte aufgereiht sind, wie an einer langen Perlenkette. An einem Ende der „Perlenkette“ befindet sich ein Anker, der alles an einer spezifischen Position festhält. Durch Schwimmkörper, die zwischen den Messgeräten positioniert sind, bekommt die ganze Kette Auftrieb und schwebt dadurch senkrecht in der Wassersäule. Diese sogenannten Verankerungen können 2-3 km lang sein und sind das erste Ziel unserer Reise.
Seit 1997 befinden sich Teile der Verankerungen schon an dieser Stelle in der Labradorsee und werden im Abstand von 2 Jahren kontrolliert. Die Position wurde aus gutem Grund gewählt. Die Labradorsee ist ein bedeutender Ort für die Zirkulation des gesamten Ozeans, denn hier befindet sich ein Ort an dem neues Tiefenwasser gebildet wird. Aufgrund von Dichteänderungen sinkt dabei sauerstoffreiches, kaltes und salzreiches Wasser ab. Die Stelle, an der sich die Verankerungen befinden ist besonders, da sich dort ein Knotenpunkt verschiedener Strömungen befindet. Alle dichten Wassermassen des Nordatlantiks kommen hier zusammen und bilden den westlichen Randstrom, der in der Tiefe Richtung Süden fließt. Durch die lange Messreihe ist es möglich Schwankungen in dieser Bildung der Wassermassen zu dokumentieren, was zum Beispiel Schlussfolgerungen über die Stärke des Golfstroms ermöglichen kann. So können auf lange Sicht potenzielle Auswirkungen des Klimawandels auf die Ozeanzirkulation abgeleitet werden.
In den nächsten Tagen werden wir die Verankerungen aus dem Wasser holen, gegebenenfalls reparieren, die Daten aus den Messgeräten auslesen und alles am Ende wieder ins Wasser werfen. Dieser Prozess läuft eigentlich immer gleich ab. Zuerst wird vom Schiff aus ein akustisches Signal ins Wasser gesendet. Dieses Signal löst die Verbindung zwischen Anker und dem Kabel mit den Messgeräten. Die Verankerung fängt dann an, zur Wasseroberfläche aufzusteigen – das liegt an den zu Anfang bereits erwähnten Schwimmkörpern. Anschließend wird von der Brücke Ausschau gehalten, wo die Verankerung genau an die Oberfläche treibt. Dann wird alles Stück für Stück an Bord geholt, gesäubert und demontiert. Erst, wenn die Messgeräte wieder mit neuen Batterien bestückt und die Daten ausgelesen sind, wird alles wieder zusammengebaut und Stück für Stück wieder ins Wasser gelassen. Als allerletztes wird der Anker ins Wasser gesetzt. Er fällt zum Meeresboden und zieht die Verankerung unaufhaltsam mit nach unten.
Abhängig von der Länge, braucht man einige Stunden für diesen Prozess. Pro Tag werden im Idealfall 1-3 Verankerungen abgefertigt. Eine wichtige Rolle spielt bei dieser Arbeit das Wetter. Drei Dinge sind hierbei wichtig: gute Sichtbedingungen, möglichst wenig Welle und Tageslicht. Im Moment ist der Nebel unser größter Gegenspieler, doch meistens verzieht er sich den Tag über und stört uns nur noch, beim Sterne oder Sonnenuntergang beobachten.
Mooring works
The second part of our research journey begins. We are currently heading north to the Labrador Sea. In the meantime, it has become really cold with an air temperature around 4°C. We are on our way to the 53rd latitude. This is the location of permanently anchored measurement devices that can measure, for example, temperature, salinity, oxygen and flow velocities. One can imagine that the measuring instruments are lined up, as if on a long chain of beads. At one end of the “pearl chain” there is an anchor that holds everything in a specific position. With the help of floating devices positioned between the measuring instruments, the entire chain receives buoyancy and thus floats vertically in the water column. These so-called moorings can be 2-3 km long and are the first destination of our trip.
Since 1997, parts of the moorings have been located at this point in the Labrador Sea and are checked at intervals of 2 years. The position was chosen for good reason. The Labrador Sea is an important place for the circulation of the entire ocean, because here is a place where new deep water is formed. Due to changes in density, oxygen-rich, cold and salt-rich water sinks. The location where the moorings are located is special, since there is a junction of different currents. All the dense water masses of the North Atlantic come together here and form the deep western boundary current, which flows in depth southward. Due to the long series of measurements, it is possible to document fluctuations in this formation of the water masses, which can, for example, allow conclusions about the strength of the Gulf Stream. In this way, in the long term, potential effects of climate change on ocean circulation can be deduced.
Over the next few days we will take the moorings out of the water, repair them if necessary, read the data from the measuring devices and finally throw everything back into the water. This process is usually always the same. First, an acoustic signal is sent into the water from the ship. This signal breaks the connection between the anchor and the cable with the measuring devices. The mooring then begins to rise to the water surface – this is due to the floats mentioned at the beginning. Then we look out from the bridge to see exactly where the mooring is floating to the surface. Then everything is brought on board piece by piece, cleaned and dismantled. Only when the measuring devices have been fitted with new batteries and the data has been read out will everything be reassembled and put back into the water piece by piece. The very last thing to do is to put the anchor in the water. It falls to the seabed and inexorably pulls the mooring down with it.
Depending on the length of the mooring, this process takes several hours. Ideally, 1-3 anchorings are completed per day. The weather plays an important role in this work. Three things are important here: good visibility, as little waves as possible and daylight. At the moment the fog is our biggest opponent, but it usually disappears during the day and only disturbs us when we are watching the stars or the sunset.
Our ocean is an incredibly vast and mysterious place. And there is no place where that is more evident than the deepest ocean area in the world: the legendary Mariana Trench. Located east of the Philippines, the Mariana Trench lies in the Mariana Archipelago in the western portion of the North Pacific. The greater area of the Mariana Trench Marine National Monument is made up of more than 95,000 square miles of ocean. Beneath these waters lie incredibly complex aggregations of submerged islands and volcanoes … and of course, an astoundingly massive trench.
Dive in with us to have your biggest questions answered about the famed Mariana Trench.
How deep is the Mariana Trench?
The deepest part of the Mariana Trench, known as Challenger Deep, is almost 36,000 feet below the ocean’s surface. For context, Mount Everest is about 29,000 feet above sea level, so the Mariana Trench is about 7,000 feet deeper than Mount Everest is tall. For one more comparison, the RMS Titanic lies at a depth of about 12,500 feet below sea level. The Challenger Deep is in waters nearly three times deeper than this ship’s final resting place.
Due to its enormous size, the Mariana Trench has at times been affectionately nicknamed the Grand Canyon of the ocean. This is certainly a picturesque image, but don’t let the mammoth size of this U.S. national terrestrial park fool you into thinking the Mariana Trench matches its size. The trench’s footprint is estimated to be 120 times larger than the Grand Canyon’s, and to reach the bottom of Challenger Deep, you’d need to descend through almost six Grand Canyons stacked on top of each other before you’d reach the seafloor.
Oh … and did we mention it’s five times wider than it is deep? It’s about 43 miles wide!
What is Challenger Deep, and how long would it take to reach it?
Challenger Deep is the deepest point of the Mariana Trench. Fewer than 30 people have ever journeyed to this area. The trek below the surface is long, dark and time-consuming, and it’s not an expedition considered lightly by scientists and explorers.
The first people to descend into the depths of this area in 1960 were oceanographers Jacques Piccard and Don Walsh, and it took them close to five hours to reach Challenger Deep. Since then, more advanced submersibles have been created, but it still takes two to four hours for modern vessels to reach such depths. For example, explorer and filmmaker James Cameron reached the seafloor in a little more than 2.5 hours in the first documented solo submarine dive to the area, and it took oceanographer Dr. Dawn Wright about four hours in 2022. It is crucial that these submersibles descend slowly and steadily beneath the surface, as the immense water pressure compounds with every mile a submersible descends. Speaking of pressure …
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What is the water pressure at the bottom of the Mariana Trench?
If you thought the depth of the Mariana Trench was its only jaw-dropping feature, think again. Water pressure is one of the most important factors affecting deep-sea life. In the ocean, pressure increases by one atmosphere for every 33 feet (10 meters) of depth. One atmosphere (a unit of measurement for pressure equivalent to average air pressure at sea level) is equal to about 14.7 pounds per square inch (PSI), which is the approximate standard atmospheric pressure at sea level. If you were to convert atmospheric pressure into weight, one atmosphere is about the weight of a bowling ball. Stay with me, friends.
If a vessel were to dive 2,000 feet below the surface, the pressure would equal that of 60 bowling balls stacked atop every square inch of that submersible. But 60 bowling balls is simply nothing compared to the pressure in the Mariana Trench. The atmospheric pressure at the depths of Challenger Deep is equal to about 16,000 PSI. That pressure is about the same as the weight of an entire full-grown elephant on every square inch of a submersible!
Need a more extreme comparison? If a human were to be placed at the bottom of the Mariana Trench, the pressure would be equal to that of 50 jumbo jets piled on top of a person!
Do any animals live in the Mariana Trench?
The depths of the Mariana Trench come with immense pressure and extreme darkness, but somehow, life finds a way to survive. Organisms that live at an extreme depth, like that of Challenger Deep, have to be highly adapted to low temperatures (typically just above freezing), high pressure and virtually no light at all.
Species found in the depths of the Mariana Trench might look vastly different from animals from other ocean depths because their anatomy has been refined to thrive in harsh conditions. At such great depths, these animals typically depend on chemosynthesis (using nutrient-rich waters being pumped out of hydrothermal vents) or descending detritus (dead matter that has fallen from higher parts of the ocean) for food, such as whale falls. Just a handful of these animals include species of octopuses and squids, sea cucumbers, amphipods, sea jellies, shrimp, sea worms and some wild-looking fish!
In 2025, more than 7,000 new species were discovered in the Mariana Trench, including the hadal snailfish (Pseudoliparis swirei). This is the deepest-dwelling fish currently known to science. Now, the fish has been dubbed “the Mariana snailfish.”
How was the Mariana Trench formed?
The process by which the Mariana Trench was created is a geologically fascinating one known as subduction. On the Earth’s surface, there are thin plates that cover the planet’s mantle, which is made of molten rock. If two of these plates collide, one pushes down into the Earth’s mantle while the other is pushed over the bottom plate. When this happens, a trench is formed from the drag of the bottom plate. This process can sometimes create incredibly strong earthquakes. The plates that forged the Mariana Trench’s creation are estimated to be up to approximately 180 million years old.
This trench was unknown to scientists until 1875. It was then that a team of explorers on the HMS Challenger measured the depth of the sea by simply lowering a weighted rope into the water. They were baffled when they measured that first portion of the seafloor to be five miles below the surface. And so was born the origin of some of the most daring deep-sea explorations known to mankind to date.
Is the Mariana Trench protected?
The Mariana Trench is in waters off Guam and the Mariana Islands. The region is protected from some human activities under its status as a marine monument. The creation of the Mariana Trench Marine National Monument signified that international, national and local leaders all recognize the importance of protecting this area.
However, just because the region is protected does not mean it’s not vulnerable to modern threats to ocean health. Plastic bags have been spotted in the Mariana Trench during several expeditions, highlighting the far-reaching impact of the marine debris problem. No corner of our ocean is safe from the ever-present threat of plastic pollution. The reality of a changing climate makes the future well-being of wondrous places like the Mariana Trench uncertain. What’s more: More than 70% of the global ocean has yet to be mapped. And what we don’t yet know about, we cannot wisely work to protect.
It’s up to us to work together to defend our ocean, from the sandy shores of our favorite beaches to the deepest, darkest parts of the sea. Together, we can work to protect our ocean as a whole, which ultimately helps protect treasured places like Challenger Deep.
Find out how you can join Ocean Conservancy’s wave of momentum to secure a healthy ocean and a thriving planet, forever and for everyone!
The post The Mysteries of the Mariana Trench appeared first on Ocean Conservancy.
Intro
At the western tip of Luzon, which is the biggest island of the Philippines, lies the small coastal town of Bolinao. Tourists seldom find their way here as it takes around seven hours to get here by bus from Manila. Still, you can spot foreigners walking around every now and then, but they really stand out among the Filipinos. A reason for their presence is often that they study or work at the Bolinao Marine Laboratory (BML), which belongs to the University of the Philippines (UP). It is one of the seven research institutions participating in the GAME project 2026. Every year, GAME brings together Master’s students from all over the world to experience different cultures and conduct globally replicated experiments in marine ecology.
This year’s Team Philippines consists of Jona, a Filipino master student of Marine Biology at the University of the Philippines, and Konstantin, a German student who is enrolled in the Master programme „Ecology and Evolution“ at Freiburg University. As part of GAME 2026, we are currently staying at BML for 6 months to run experiments about the influence of underwater soundscapes on the colonization of marine hardbottoms.
Where are we?
At the BML, we live in a dormitory together with many other students and scientists mostly from the Philippines and a few international interns. At