May 15 2008
May 15 2008
Greg Buikema recovers the latest rock dredge from the water.
Kate Hendry and John Swartz help to improve the otter trawl net.
Laura Schejter and Kate Hendry picking through some of the material brought up in a trawl today.
One of the species found by Laura Schejter and Kate Hendry in dredges from the Shackleton Fracture Zone.
Hello everybody! It’s me again, Laura Schejter, the Argentinean observer. This time, I’ll talk about something more specific regarding my work and why I am here.
When scientists were organizing this cruise, planning sampling sites and working areas, they included Argentinean jurisdictional waters. If a foreign vessel is planning to navigate and especially to work in the territory of other countries, they have to ask for permission to the government first and offer places for observers of that country, in order to monitor the activities that will be take place during the cruise.
The data obtained during the cruise must also be shared between both governments. So, in other words, when the US Embassy in Buenos Aires received the project of Dr. Laura Robinson and Dr Rhian Waller dealing with cold-water corals, and asked for permission to develop it, the Argentinean government selected me to participate in this cruise as an observer, as I have experience working with invertebrates associated with the seafloor and I’ve been sailing and participating in national and international research cruises since 2000.
After I accepted to participate in the cruise (a really great experience for me), I contacted Laura and Rhian for more details regarding sampling and samples. The observers are just supposed to watch what’s going on during the cruise, but I’d be happier with a more active position. So I asked about the possibility to work and collaborate on board with the other people, offering a small project dealing with the identification of the sponge species from the samples. I offered that because sponge taxonomy (identification) is one of my research lines as an Assistant Researcher at CONICET (National Council for Scientific and Technical Research), working at INIDEP (National Institute for Fisheries Research and Development). I was very happy when Rhian and Laura agreed to having me be a part of the active research going on during the cruise.
So...why working with sponges? I know they are not as attractive as corals to normal people, but let me tell you a few things about these animals.
First of all, they are animals, not plants as many people believe! They are aquatic, sedentary (sessile), multicellular animals with different body morphologies, but without true tissues or sensory organs. They filter water to eat, breath and excrete products, and they’re probably the most efficient vacuum cleaners in the sea, as some species are able to pump up to 10 times their body volume per hour.
Although numbers change every day, there were approximately 7,000 "valid" species published worldwide in 2000, but probably there will be at least 15,000 living species (or more) in all the world's seas and lakes.
New sponge species are being discovered every year, and there are actually a couple of new species that were discovered in Antarctica just in the last year. I also recently described a new species from Argentinean waters together with other researchers, so who knows if we are not going to collect a new “undiscovered” sponge species during this cruise.
Sponges are also used as homes for small organisms like microcrustaceans and worms, and they also can be found in symbiosis with mollusks, crabs and hermit crabs, acting as camouflage in order to avoid predators. Additionally, sponges could be key species in detecting habitat quality, since they are sensitive to pollution and are not collected frequently in intensively fished areas.
So...do you still think that sponges are boring? Well... the added value is that nobody in Argentina is working today in sponge identification, which is the main reason that pushed me to start with this research line a few years ago, when nobody was able to identify the sponges in my own samples when I did my PhD, so....I had to do it by myself! The result, of course, is a happy ending for me (or beginning), because although I’m just starting with this kind of research, I find it really exciting, and there are a lot of things to do. The possibility to link Argentinean, Magellanic and Antarctic sponge fauna with samples from this cruise is really attractive, and also to get specimens of very deep waters, as our sampling sites sometimes reach 3000 m depth.
So... It’s time to say “good bye” now. I hope you learnt something more about sponges, and next time you hear the word “sponge” you can think of something a little different than the one you use for having a shower!
Laura Schejter
In other news today we collected two great hauls of fossil corals and are now steaming westward into the central Drake Passage to an unnamed seamount. Stay tuned for news of that catch tomorrow.