The hadal zone, named after Hades the Greek god of the underworld, is the absolute deepest layer of the ocean. Occurring in the ocean’s trenches from 6000 meters down to the bottom of the Mariana Trench 11,000 meters below sea level, the temperature of the hadal zone or hadalpelagic layer is constantly just above freezing. The pressure here is over 8 tons per square inch, equal to 48 Boeing 747 jets, making it very difficult for life here to flourish. Yet marine creatures can be found even here, one of the most inhospitable environments in the world.
Foraminifera of the Hadalpelagic Zone
Perhaps one of the most abundant sea creatures in the hadal zone are the foraminifera – single celled protists living in the muck of the world’s deepest trenches. Scientists recently discovered 432 different species of foraminifera in the dirt of Challenger Deep, the bottom most part of the Mariana Trench, says National Geographic’s John Roach in his 2005 article ““Life is found thriving at Ocean’s Deepest Point”.
Foraminifera can be found throughout the ocean and constitute over half of all sea life found in the deep sea. Those in the hadal zone have a soft shell surrounding their body – soft because a hard shell would collapse under the crushing pressures of the hadalpelagic layer. These shells are created from materials that sink down from the sea’s surface. Some scientists believe these creatures could resemble Earth’s earliest lifeforms.
Finding Fish in Ocean Trenches
Although the hadal zone isn’t exactly fish friendly, a few piscine creatures can be found down here. The BBC article “Deepest ever’ living fish filmed’ (Rebecca Morelle, 7 October 2008) describes a few of these hadalpelagic sea creatures. The deepest fish on record is the Abyssobrotula galatheae which in 1970 was dredged up from a depth of 8 kilometers in the Puerto Rico trench. Another hadal zone fish is the Pseudoliparis amblystomopsis. Measuring 30 centimeters long these active fish were filmed at a depth of 7.7 kilometers.
Exploring the Hadalpelagic Zone for Marine Life
Although the hadalpelagic layer is not the most biodiverse place in the world it does support a variety of creatures. A hadal zone comb jelly was found in 2002 at a depth of 7,217 meters in the Ryuku Trench off of Japan says the Census of Marine Life in their web article “Benthic Comb Jelly”.
As people continue to explore the depths of the oceans more sea creatures are sure to be found. According to the BBC article “Meet the creatures that live beyond the abyss” (Rebecca Morelle, January 2010), in 1995 the Japanese vessel Kaiko found a sea cucumber, a shrimp and a worm in the hadal zone. In 2009 Nereus, from the Woods Hole Institution in Massachusetts, passed a series of test showing it too was ready to explore the hadal zone. As Morelle quotes Lisa Levin from the Scripps Institute of Oceanography – “We have seen more of the Moon that we've seen of our trenches.” Future exploration is sure to shed light on some interesting marine animals.
Sources:
“Layers of the Ocean”. NOAA National Weather Service. 21 April 2010. Srh.noaa.gov.
Megan Jungwi - Megan Jungwi started her freelance writing career in March 2009. Although new to online writing Megan has long been passionate about the ...
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