Hydrothermal Vent Systems & Deep Sea Gigantism

Hej hej!

With the final week of Aquatic Ecology on the horizon, things are beginning to wind down for me here in Lund, for the moment anyway. This past week had everyone in class working in pairs to create PowerPoint presentations regarding a specified aquatic topic. My partner and I were given the topic of deep sea hydrothermal vent systems. Although I could happily write my entire post regarding this topic, for your sake, I will restrain myself. Instead, I would like to recommend the James Cameron documentary Aliens of the Deep, which discusses in detail why hydrothermal vent systems are so unique, as well as how our understanding of these systems is providing great insight into the search for extraterrestrial life. I’ll be the first to admit that the beginning, and end, of this documentary is slightly on the cheesy side, but the actual footage and information is brilliant!

Other topics presented during the past week were regarding mangrove forests, seagrass beds, fisheries, aquaculture, marine mammals, seabirds, and climate change. Overall, the presentations were incredibly impressive and insightful, as well as a great opportunity to practice public speaking.

During this final week, I will be completing my individual project, a 15 minute presentation on an aquatic topic of my choice. I decided to look into the theories and mechanisms behind deep sea gigantism. As many of you may have heard, during this month there have been two publicized findings of deceased giant oarfish surfacing on the southern coast of California. Since these fish truly represent a gigantic life form, I decided to include them into my presentation as somewhat of a case study. However, there is a vast amount of unknowns about this species, mainly because of all the issues that come along with studying in the deep sea, i.e., a lot of habitat to cover, expensive research vessels, largely time consuming, etc. What can be especially tricky in studying such mesopelagic organisms (organisms that live in the middle bit of the water column verses living at the water surface or the ocean floor) is that they migrate vertically as well as horizontally in the water column.

copyright AP Photo/Mark Bussey

Copyright AP Photo/Mark Bussey. Photo showing one of the two fish that washed ashore in Southern California during the month of October, 2013.

However, despite all the challenges presented by the deep sea, researchers have slowly been collecting scraps of evidence to support the hypothesis behind how this giant creature ekes out a living in the depths of the sea. Possibly one of the most interesting facts I have learned is that the giant oarfish positions itself vertically in the water column, instead of horizontally like many common fish species. It has been hypothesized by some that this vertical orientation is an adaptation to avoid predation because it decreases the oarfish’s visibility in the water. However, more research on live specimens is required before any conclusions can be drawn.

Photo credit: Benfield et al. 2013. Stills taken from video footage of the giant oarfish swimming off the coast of Mexico.

Photo credit: Benfield et al. 2013. Stills taken from video footage of the giant oarfish swimming off the coast of Mexico.

For me, what I find to be the most interesting question is the purpose of the occipital crest (the enlarged fin rays at the head of the oarfish). Is it the result of sexual selection? Are there differences between males and females? Is it a sensory organ? Hopefully with time some of these questions will be answered!

Photo credit: Tubil. Artist rendition of the giant oarfish

Photo credit: Tubil. Artist rendition of the giant oarfish

Not much new to report beyond class. Still trying to get outside as much as possible to enjoy the fall colours… as well as the daylight hours, which are rapidly getting shorter and shorter. On Friday I caved and bought myself a proper pair of running shoes. I see so many runners when I’m out and about in Lund that I think some kind of weird subliminal message penetrated my inner psyche initiating this need to run, well perhaps more accurately, this need to jog ever so slowly… running will hopefully come later. Luckily, I’ve been told by many of the Swedish students that Lund is pretty good for being able to run/jog slowly all year round. It seems that the common weather trend here is that even if it does snow, the snow never sticks around for long. Cool. This ought to be quite different from the slushy, sloppy, and wet Toronto winters I have grown accustomed to.

I believe this is where I will end my post for this week. I’ll be looking forward to writing my next post, which will happen after my first week of Fisheries Ecology. Before I depart however, I would like to share with you a poem I recently read in Mark Kurlansky’s book ‘Cod: A Biography of the Fish that Changed the World’.

The codfish lays a thousand eggs
The homely hen lays one.
The codfish never cackles
To tell you what she’s done.
And so we scorn the codfish
While the humble hen we prize
Which only goes to show you
That it pays to advertise

– Anonymous American rhyme

Take care,

Abby

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