- Published on March 09, 2010
Naw, I don’t work with blue algae (or blue-green algae to be correct). But the red algae and the wee green and brown algae that live inside them are the focus of my experiment here in Antarctica. My work focuses on how these small filamentous green and brown algae, which we call endophytes, affect the growth rates of the red algae in which they live inside. Previously work has been done in Antarctica showing that these filamentous algae grow on the outside of the red algae when there are no herbivores present, but are mainly present inside the algae when herbivores are present. The main herbivores of these algae are small crustaceans called amphipods, which live in the algal canopy here in Antarctica. This is a pretty neat community and different from other comparable near shore communities worldwide. What I want to know is whether small filamentous algae growing inside the algae are detrimental to algal growth.
In order to test for a relationship between growth rates and endophyte infection I have begun an experiment which includes transplanting algae with varying quantities of endophytes and watching them grow over a season. The way we go about this is more complicated than it seems at first glance. First we dive to scout out a location where the species in question is abundant and where we can deploy concrete substrates, onto which the algae will be transplanted. This can be tricky around Palmer Station because much of the coastline can be steep and quickly drop to over one hundred feet, leaving me no shelf on where I can place these structures. Also, algal communities vary with the location, so what you find a lot of at one place may not even be present at another.
After we have found a good location we dive again to deploy the concrete substrates. These concrete squares have threaded stock projecting up at each corner and an eye bolt in the center. The eye bolt is clipped to a cable on a strong metal arm or davit enables the substrate to be carefully lowered into the water to the divers. We attach lift bag is attached to the eye bolt once it hits the water. Lift bags are extremely useful in this situation because in diving, your buoyancy means everything. The air put into the lift bag counteracts the weight of the concrete and allows us to float the heavy object down to our site without exerting too much energy ourselves. All substrates are lowered to the bottom in this fashion and placed in secure, flat areas close to each other so can be found easily. After we bring all the substrates to the bottom we collect over 70 individuals of the species in question. So far we have been able to work with Gymnogongrus turquetti and Myriogramme mangini, which unfortunately these tongue –twister Latin names have no common names. Any suggestions?
All algal collections are brought back into the aquarium building at Palmer Station. They are sorted into groups based on quantity of visible endophytes (low, medium, and high) within their bodies. Selected individuals are weighed and photographed and then placed in a rope attached to a rack with a specific name (nothing like Jimmy, Mack or Buddy, more like 24C). I give the algae names so that I can track the individuals over time and compare photographs and weights after the growing season. This is a long process (brrrrrrr…..) and needs to be done quickly so that the algae get back out into their natural environment as soon as possible. Redeployment includes diving down to the substrates, bolting the racks to the threaded uprights, tightening prefixed nuts, and then tightening the ropes with algae down using zip ties. Not too complex with bare hands but with dry gloves, oh brother! Our first deployment went quite smoothly. We were definitely spoiled.
My first site is near the shipwrecked Bahia Paraiso, right in front of Palmer Station. My substrates are around forty feet deep, and the most abundant algae found here is G. turquetti. My second site is on the south side of Norsel Point, along the western wall of a small cove. This is a ‘wall’ dive generally, but there is a small shelf between twenty and thirty feet where I placed my substrates. This cove is replete with M. mangini, but is also frequented by a large leopard seal. The day Chuck and I put out the substrates we were at our safety stop when the seal alarm went off. Except, since we were so shallow instead of using the piercing siren alarm the tenders used the engine as an alarm. I was not too scared but I definitely bolted to the boat after hearing it which annoyed my buddy Chuck (he wears one more layer of hoods for insulation on his head than I do and doesn’t hear quite as well as I do under water; he was not aware of the recall - oops). My tender Jim says I’ve never gotten out of the water so fast. The next day we tried to deploy all the racks with my algae on them. We put in two and were working on our third rack when the real alarm went off. Holy moly, that thing is bone-harrowing and loud, quite different from a revving engine. I have to say that I was cold while diving that day, but I immediately warmed up when I heard that siren. We had to go back the next day to put out the last two racks of algae which took two dives because of a glove leak (brrrrrr again) and rougher conditions. Field manipulations are never as easy as they seem.
I hope to find and complete my next site shortly and then we will begin bringing in racks for reweighing and photographing soon after. This project seemed quite a bit simpler before we began deployment, but it has been gratifying to start this work and begin analyzing the weights and photographs. I am ready and rested for site number three.