Sea Cucumbers

(Post by Marina Desjardines)

The ocean is a vast ecosystem covering a majority of the earth’s surface. It is filled with a large diversity of creatures with a large range of sizes. Many of these creatures may not even look like living things such as the corals and the sponges. It is home to some cartier love bracelet
of the strangest and creepiest living creatures on earth, many of which haven’t even been discovered yet. It is quite disturbing actually to think of how much is unknown of the creatures that live in the depths of the ocean. Others however are harmless and what some might even call cute like the sea horse or the cuttlefish. One of the strangest, yet harmless, creatures of the ocean is the sea cucumber and of particular interest, the sea pig.

The sea cucumber, which you might guess from its name, has an elongated cylindrical body. The name may be misleading due to the fact that most sea cucumbers don’t really look like the vegetable. However, this one actually does.

 

Other than this exception, the sea cucumber does not look like something you would want to eat, although they are eaten in certain parts of the world. Sea cucumbers can be a range of different colours and some may have additional or exaggerated features on the surface of their bodies like this one below.

 

The sea cucumber has a flexible body wall with circular and longitudinal muscles used for moving along the ocean floor. They can range in size from several centimeters to over 1 meter in length (Pechenik, 2015). They have rows of tube feet fake cartier bracelet replica
or “podia” along the sides of their bodies (Pechenik, 2015). The tube feet are extended using hydraulic cartier jewelry replica pressure to help them move (Pechenik, 2015). These tube feet are cylindrical shafts that may have a sucker at the tip or may be coated in a sticky mucous (Pechenik, 2015). Some species may have reduced tube feet, or in some species that are specialized for burrowing, they may even be absent altogether (Pechenik, 2015). Around the sea cucumbers mouth are modified tube feet or “tentacles” used for catching food and picking up sediment in feeding (Pechenik, 2015). These are also extended using hydraulic pressure (Pechenik, 2015). There are four different types of feeding tentacles including dendritic, peltate, pinnate, and digitate as seen how much does a cartier bracelet cost
below in figure 1.

 

The sea cucumber is unique in that it has a structure called a respiratory tree (Pechenik, 2015).  The respiratory tree is connected to the cloaca which is a common structure used for the release of waste and reproductive products (Pechenik, 2015). The cloaca is responsible for bringing water into the respiratory tree (Pechenik, 2015).  In other words, the sea cucumber actually breathes through its anus cartier bracelets making it one of the stranger creatures in the ocean. The sea cucumbers defense mechanism is another one of the reasons it is one of the strangest creatures in the ocean. When it feels threatened it will expel some or all of its internal organs out of its anus, I’m guessing in order to confuse the predator. This process is called evisceration and is displayed in the picture below.

 

You might think that this process is useless and might be more of a suicide mission. However, due to the sea cucumbers amazing regenerative abilities it is able to regrow all of its organs. This ability leads us to the next strange fact about the sea cucumber. The anus of the sea cucumber is quite often home to another strange creature called the pearlfish. The pearlfish will actually swim up the cloaca of the sea cucumber and hide callingallcakes.org there (Simon, 2014). Depending on the pearlfish, they might have a commensal or parasitic relationship (Simon, 2014). In the commensal relationship the pearlfish is just using the sea cucumber as protection from predators which has no effect on the sea cucumber (Simon, 2014). However, some pearlfish will actually feed on the gonads of the sea cucumber which has a negative effect on the sea cucumber but is not detrimental since it can regenerate the gonads. (Simon, 2014).

The sea cucumber is an invertebrate, defined as an animal lacking a spine or backbone. It is part of the Phylum Echinodermata, which comes from the Greek word meaning replica cartier spiny skin. This is seen in the sea stars and sea urchins, which are also part of the phylum, due to the calcareous exoskeleton that is lacking in the sea cucumbers. The sea cucumbers make up the class Holothuroidea which contains about 1200 species (Pechenik, 2015). As I mentioned earlier, of particular interest is the sea pig. The sea pig, otherwise known as Scotoplanes globosa is a sea cucumber of the order elasidpodida, and family Elpidiidae (Shapiro, 2012).

Sea cucumbers can be found at various depths in the ocean. The sea pigs, however, live in depths of 2100m-6770m and are found in large numbers (Shapiro, 2012). These animals live in pitch black and have a transparent, almost pink coloured, body wall. They have exaggerated tube feet on their sides and additional modified tube feet on their backs that help them find food in the dark (Simon, 2015). Below are pictures of a sea pig taken out of the water (left) and one on the ocean floor (right).

 

 

 

 

 

 

As you can see they are pretty weird looking creatures. The sea pigs differ from the sea cucumbers that live in the shallower waters in that they have lost the need for the respiratory tree and actually breathe through their thin skin (Simon, 2015). In addition, they have also lost their need for evisceration since the number cartier love bangle of predators in those depths are much less than in shallower waters. This is also probably due to the fact that re-growing organs after evisceration takes a lot of energy and the amount of food available to the sea pig to make up for it is not enough (Simon, 2015). The sea pigs have peltate tentacles that they use to feed on marine snow that rains down on the ocean floor and sediment. Although hermes replica jewelry it is relatively safer in deep waters, the sea pig does still have a defense mechanism in the form of unpalatable chemicals in their skin (Simon, 2015). For a funny video describing the sea pig click here (https://www.youtube.com/watch?v=_y4DbZivHCY).

I used to believe cartier love bangle the sea cucumber to be a unanimous, disgusting blob that lurks in the depths below. Not much has changed beyond the fact that in my eyes. Yes, indeed they are still disgusting blobs, and yes the lurk, but now with a purpose and greater understanding. For example, I found the relationship between the Sea Cucumber and Pearl fish to be both unique and surprising. It’s an ironic happenstance that a fish would take refuge inside of a sea cumber and in most cases ingest its gonads. Neat thing is, the sea cucumber can regenerate its organs and keep on lurking. As useless and mysterious as the Sea Cucumber may still seem, it serves its purpose on the ocean floor playing its important role in the underwater ecosystem of deep sea dwellers.

References

Conand, C., 1998. Holothurians. In: K. E. Carpeneter & V. H. Niem cartier bracelet of anastasia steele fifty
(eds.) FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Volume 2. Cephalopods, crustaceans, holothurians and sharks. Food and Agriculture Organization of the United Nations, Rome, pp. 1158-1184.

Pechenik, J. A. (2015). Biology of the Invertebrates. New York, NY: McGraw-Hill Education. P 513-518.

Shapiro, L., 2012. Encyclopedia of Life. Scotoplanes globosa Sea Pig. Retrieved March 20, 2016 from http://eol.org/pages/599675/overview.

Simon, M., 2014. Science. Absurd Creature of the Week: This fish swims up a sea cucumber’s butt and eats cartier bracelet
its gonads. Retrieved March 21, 2016 from http://www.wired.com/2014/02/absurd-creature-of-the-week-pearlfish/

Simon, M., 2015. Science. Absurd Creature of the Week: Chubby little ‘Sea Pig’ tastes more like poison than bacon. Retrieved on March 21, 2016 fromhttp://www.wired.com/2015/04/absurd-creature-of-the-week-sea-pig/