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Creatures of the Deep


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Creatures of the Deep

Three weeks ago, 20 scientists set out on an expedition to uncover the great mysteries of the earth. By dredging the ocean floor, we have obtained countless rock samples that may hold valuable information. But what we didn't expect to find in our dredges were some friendly, lovable sea creatures that hitched a ride from great depths. I guess they wanted to see what all the fuss was about, too!
 
Our first surprise critter came along on one of our very first dredges--a shrimp named Harold! Unfortunately, this little guy seems to have had quite a struggle on his way up, given that all that's left is his head. This made it quite difficult to identify Harold, but I've decided that he probably belonged to the suborder Dendrobranchiata, a type of decapod. These crustaceans have ten feet (hence the name), although this feature could not be confirmed on Harold. They are mostly marine and are typically found between 40N and 40S. Creatures like Harold are scavengers and eat things such as fish, krill, copepods, radiolarians, phytoplankton and other little critters.
 
Several dredges later, we were pleased to find that we had brought up a sea star, another friendly creature to add to our collection. Not-so-originally named Patrick, we endearingly gave him the nickname Stumpy, due to his missing arm. Now typically, sea stars can regenerate lost arms, but since this usually takes several months or even years, Stumpy didn't have adequate time to do his thing; but we love him just the same. These creatures can be found from intertidal zones all the way down to abyssal depths of 6000 m. Since our dredges are scraping the very deep ocean floor, it's likely that Stumpy was a benthic sea star of the order Notomyotida. They are only found in marine environments and most eat microalgae, sponges, bivalves and snails.
 
It quickly turned into a family reunion of sorts when one of our dredges contained one of Stumpy's cousins, Franz Josef Wilhelm Alexander III, and soon after, Franz's brother Hermes. These guys are brittle stars (Ophiuroids), which are echinoderms just like sea stars. These organisms have five long, whip-like arms that can sometimes reach up to 60 cm. Their arms are mainly used for locomotion and also to move food to the mouth. These organisms are found from the poles to the tropics, and over 60 species of brittle stars are bioluminescent! They have a skeleton of calcite and are generally scavengers or detritivores (meaning they eat whatever floats into their mouths).
 
Last but certainly not least, one of our dredges caught another familiar face. Frederick is an anchovy that must have been curious about what all these rocks were for, because he swam into our dredge and rode it all the way to the surface. These fish are small, with blue reflections that are caused by a silver longitudinal stripe. Anchovies are prey for most predatory fish, and are also used by humans to flavor dishes, sauces and condiments because of their strong taste--but we would never dream of eating Frederick! They range anywhere from 2-40 cm and are concentrated in temperate waters. These fish typically eat plankton and fry (recently-hatched fish).
 
While I'm sure we are bound to bring up many more creatures during the remainder of the cruise, this was just a little taste of the types of critters that are swimming around below us.

by Joanna Rose