Exploring the Mariana Trench

Everything Including the Kitchen Sink (and Refrigerator)

SOI/ Jill Bourque
Dec. 04 2014
We can take quantitative samples of the sediment returned by the grabs using syringe cores to answer questions about faunal communities and organic composition.
We can take quantitative samples of the sediment returned by the grabs using syringe cores to answer questions about faunal communities and organic composition.SOI/ Jill Bourque

Science at sea is not just science, but rather a cooperative effort between science, endurance, and creativity.  Imagine that you are going to be on a tiny floating island for a long time with whatever equipment you think to pack.

It would be, and is, quite challenging trying to anticipate everything you will need, and the things you are not expecting to need.  Rarely does science cooperate perfectly and go according to plan, which on a research cruise is most certainly true.  The fate of our research is tied to the ship, weather, and the ocean; and inclement weather can reduce the number of days in which science can be done. Additionally, gear can be lost and/or broken, or a surprise, such as the discovery of an unexpected habitat or animal that requires a different kind of sampling method.

More fish please

We even bring a cold van where we can keep sediments and animals cold. At 4ºC, the climate inside the van is much closer to the temperature they normally survive at.
We even bring a cold van where we can keep sediments and animals cold. At 4ºC, the climate inside the van is much closer to the temperature they normally survive at.SOI/ Jill Bourque

On cruise to the Kermadec Trench earlier this year, we were tasked with finding a way to collect more fish from the extreme trench depths to help determine their physiological tolerance range.  However, the low density of these fish made collecting these specimens a challenge, even with baited traps. To increase our odds, scientists on board fabricated a new trap to help accomplish these goals.

 

 

Enter the Wee Trap

Contrary to the name, this device is not a plumbing part installed in our bathrooms.  Built by hadal expert Alan Jamieson from the University of Aberdeen in Scotland (wee being a Scottish term for little), the Wee Trap delivered the answer to our collection problem.  Using his extensive knowledge of hadal landers, the Wee Trap was built out of spare parts that we had with us at sea.  Alan built the Wee Trap with the purpose of catching both hadal fish and amphipods to complement the large baited trap we were already using.  Although improvised, the Wee Trap provided us with a wealth of fish and amphipod specimens.  Due to its success, we incorporated the Wee Trap in our sampling strategy on the Mariana cruise to again help us catch those elusive animals.

Scientists deploy the Wee Trap from the aft deck. The jaws of the grabber remain open until it hits the sea floor.
Scientists deploy the Wee Trap from the aft deck. The jaws of the grabber remain open until it hits the sea floor.SOI/ Jill Bourque

The little trap that could

During this expedition, the Wee Trap has again paid dividends, bringing us precious snailfish and amphipods from the deepest darkest depths.  We have attached additional cameras to the Wee Trap to see how fish and amphipods are behaving around the trap, providing insight into their natural modes of survival.

Scientist Patty Fryer and WHOI Specialist Casey Machado attach the grab sampler to the new arm on the Wee Trap.
Scientist Patty Fryer and WHOI Specialist Casey Machado attach the grab sampler to the new arm on the Wee Trap.SOI/ Paul Yancey

We have also been successfully sampling bottom sediments with the Free Vehicle Coring Respirometer (FVCR) and the rock grabber, my motto is always “the more mud the better.” These sediments are vital to understanding the complex link between organic food supply originating in the water column, pressure from depth, and sediment composition with the faunal communities (from small microbes to large fish or megafauna) living in the sediment. Unfortunately, a new problem has arose due to the difficulties of sampling sediment from the sea floor.  Again, enter the Wee Trap.  This time it has been modified with an extra arm to which we attached a rock grabber fabricated by the fantastic engineering crew aboard Falkor.  The additional mud samples collected through this modification allows sampling of more locations on the sea floor. This provides us with insight into the spatial variability of sediment communities and parameters among trench locations, even with sediments collected by the rock grabber at similar depths.  Every sample we are able to collect is invaluable and brings excitement for the entire mud crew.  On our floating island, the Wee Trap has repeatedly answered the call of discovery, the culmination of talented creativity, and unforeseen scientific needs.


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