Breaking Down Challenger Deep

    Most people know about Mount Everest, Earth’s highest peak. At 8.8 kilometers above sea level, Mount Everest is undeniably larger than life, but what fewer people know is that the Mariana Trench, formally the deepest place on Earth, can fit the entire mountain with room to stretch. The Mariana Trench is a crescent-shaped trench in the Pacific Ocean, with a depth of 11 kilometers, and at the very bottom of the abyss is Challenger Deep: the closest we can naturally get to the Earth’s core. 

Challenger Deep can comfortably fit Mt. Everest within its depth.

Numerous theories have been made about what lurks beneath the ocean’s waves, and even more have been made about Challenger Deep. People are inevitably fascinated by the idea of such a gargantuan trench in the middle of the ocean and all the secrets it must hold. Although no lurking alien species have been discovered (yet) in this trench, scientists have explored its crevices and found several organisms that call it home. Of these organisms, several are too small for the naked eye to see, and these “microbial communities” curiously thrive in such resource-scarce environments. 

Recent research has focused on analyzing the environment of Challenger Deep to better understand how these microbiomes survive in an otherwise inhospitable environment. Samples were collected from the indented slope that separated Challenger Deep from the rest of Mariana Trench, effectively obtaining sediment from the environment many of these microbiomes reside in. 

The sediment in the study was collected from different parts of Challenger Deep.

    The point of collecting sediment is to analyze the elemental cycle of this hostile environment. Elemental cycles refer to the natural processes that recycle and reuse elements present in nature like carbon and nitrogen: for example, humans breathe in oxygen and exhale carbon dioxide, which plants then respire, only to produce oxygen as a byproduct, and so, the cycle continues. Elemental cycling in “hadal” environments, oceanic trenches past a certain depth, is very interesting for scientists to examine due to how limited resources are in such extreme conditions.
    

Challenger Deep is located in the southern end of the Mariana Trench, an area with a high tectonic activity that frequently results in shallow earthquakes in the area. These tremors disturb the sediment in the surrounding area and shift it towards the abyssal seafloor. Volcanic ash, embedded in the Earth’s crust, can make its way to deep-sea locations this way, and it brings heavy metal with it, many of which are hypothesized to be alternate means of energy transfer for the microbiomes in these hadal regions. 

The uniqueness of Challenger Deep makes it a strangely imperfect environment for organisms like these microbiomes to flourish. While elemental cycling of these regions has been largely questioned, examining the sediment of the local sea bed can offer insight into the varying mechanisms organisms may have had to adapt to acclimate to this hostile environment.

Elemental Cycling in the ocean reuses and recycles elements to sustain life.