New Shrimp Species in the Deep Ocean

This post is part of a 4-part series by students of a Biological Oceanography course at Pennsylvania State University taught by Dr. Mónica Medina.

When you think of shrimp you most likely picture delicious scampi or your seafood dinner while on vacation at the shore. However, what most of us do not realize is that there are thousands of different species of shrimp found worldwide in a variety of environments. The most common shrimps that many know and love to eat are found on the seafloor along the coast and throughout rivers, estuaries, and even lakes. Practically any type of marine environment has a species of shrimp adapted to living there. Yes, even hydrothermal vents.

Orifice of hydrothermal vent at the Von Damm vent site. Notice the vent shrimp in upper right. (Credit: NOAA Photo Library)

As ocean exploration technology has improved researchers have been able to better study the life found in deep sea environments, like hydrothermal vents. Hydrothermal vents are located on the seafloor where tectonic plates are moving apart and geothermally heated water escapes from the cracks. The hot water shoots out of the vents in a huge plume (known as black smokers) and creates an extreme environment where exceptionally hot (up to 400°C or 750°F!) and cold water converge. When scientists reached the hydrothermal vents they found them teeming with life. A site known as the Mid-Cayman spreading center was recently found to be the world’s deepest, and possibly hottest, seafloor spreading center and is located at a depth of 2300-4960 meters [1]. At the spreading center there are two hydrothermal vent fields just 12 miles apart from each other and in 2011 a brand new species of shrimp, Rimicaris hybisae, was found at both [2]!

Rimicaris hybisae from the Von Damm hydrothermal vent site, Mid-Cayman Rise. (Credit: NOAA Okeanos Explorer Program)

Even though Rimicaris hybisae are known as eyeless shrimp, it does not mean that they lack all vision. Rimicaris hybisae actually contain a light-sensing organ, which is located on their backs. This organ contains a certain pigment with an absorption rate that's very similar to rhodopsin, allowing the shrimp to detect low levels of illumination. It is believed that they use this low level of light to navigate around the hydrothermal vents [3].

A large accumulation of shrimp at the Von Damm vent field. (Credit: NOAA Photo Library)

The eyeless shrimp live in the rich sulfide chimneys. They seem like a social marine species since thousands of shrimps are living in the same chimney. The shrimps will move on to a new vent when an existing one is no longer viable [4]. The food of this species consists mostly of microorganisms. They consume the microorganisms that grow in the chimneys or that are floating in the water [5]. Although the eyeless shrimp live in the deep ocean where the pressure is extremely high with low temperature, scientists have discovered that they do have predators that will go after them. Bythograeid crabs, hydrothermal vent anemones, Chorocaris chacei and Alvinocaris makensis (another type of shrimp) will all eat this of this species. No known defense mechanisms are found in the eyeless shrimp to protect them from these predators [4].

A close relative of Rimicaris hybisae, R. exoculata, a genus and species that were both originally described and named by the late Austin Williams, who worked with IZ as part of NOAA's National Systematics Lab. (Credit: Denisia 18 via EoL).

The recent discovery of these shrimp just adds to the endless mystery of our ocean. New species are found all the time and we will never stop learning about what goes on beneath the waves. 

By Emily Anderson, Jung Eun Oh, & Kristen Hartwick 

 

Further Reading

[1] Nye, V., Copley, J., Plouviez, S. (2012). “A new species of Rimicaris (Crustacea: Decapoda: Caridea: Alvinocarididae) from hydrothermal vent fields on the Mid-Cayman Spreading Centre, Caribbean.” Journal of Marine Biological Association of the United Kingdom, 92(5). 1057-1072. 

[2] Mustain, Andrea. "Eyeless Shrimp Discovered at Deepest Volcanic Vents." LiveScience. TechMedia Network, 10 Jan. 2012. Web. 16 Apr. 2015.

[3] Lee Van Dover, Cindy, Ete Z. Szuts, Steven C. Chamberlain, and J.R. Crann. "A Novel Eye in 'eyeless' Shrimp from Hydrothermal Vents of the Mid-Atlantic Ridge." Nature 337 (1989): 458-60. NPG. Web. 15 Apr. 2015.

[4] Vereshchaka, A. 1997. Comparative morphological studies on four populations of the shrimp Rimicaris exoculata from the Mid-Atlantic Ridge. Deep-Sea Research, 44(11): 1905-1921.

[5] Van Dover, C., B. Fry, J. Grassle, S. Humphris, P. Rona. 1988. Feeding biology of the shrimp Rimicaris exoculata at hydrothermal vents on the Mid-Atlantic Ridge. Marine Biology, 98: 209-216.