UAB in Antarctica
overview     crew     history     sights/sounds     related links crew journals    
crew journals
Anne Fairhead, Ph.D.
Postdoctoral Research Fellow

The Substrate Experiment, part 2

Journal By Anne Fairhead

Posted On 3/5/2004 2:27:08 PM

Once the substrates were finally in place we could begin to work on collecting the algae which is not a simple task. The two species I am working on (Desmarestia anceps and D. menziesii) account for a large part of the macroalgal biomass here, and as you can see in the first photo, D. anceps is not a lightweight alga. D. menziesii is often a little smaller, but is much harder to remove from the rocks- the holdfast (the bit of the alga that attaches to the rock) is very strong which enables it to stay attached even under very high water motion, but this also enables it to attempt to stay attached even under very persistent cutting and prodding by marine biologists.

We decided to collect only half of the algae the first day because after collecting them we had a lot of work to do to get them ready to go back down onto the substrates. So we did two rounds of collecting, processing and attaching to the substrates. When we retrieve the algae at the end of the experiment we will do the same thing, which will make it a bit easier to get everything done.

Processing the plants was a team effort that kept us in the lab and aquarium room all day (the weather on the first day of processing was spectacular so it was not an easy thing to stay inside- luckily we are a bunch of committed scientists). For every plant we collected we had to cut off four tips(see the photo of Chuck). These tips were weighed (see Maggie) and then three tips were attached to the appropriate position on the particular rope- you can see a single D. anceps in the photo but some ropes had two tips.

The ropes were then attached on each end to a rack by cable ties, which fits neatly onto the substrates. Each substrate had 12 tips altogether, 6 of each species, and the positions were randomly assigned (by a fairly technical process involving names on bits of paper and a jar). The rack of algae you can see in the photo is labeled UVT, which means it was destined to sit on a substrate under UV (ultraviolet radiation) transparent Plexiglas. This substrate is grouped with two other substrates- one with no cover and one with UV opaque Plexiglas.

The forth tip was frozen, but firstly a smaller sample (about 0.5 gm) was cut and weighed to be used for phlorotannin analysis. So I was in the lab chopping these samples up, and then grinding them in methanol, which is the start of a three-day process of extraction to get the samples ready to be able to conduct the phlorotannin assay. These assays will let us know what the initial concentrations of phlorotannins were in the algae. This must be done in the dark and the samples kept on ice, so it is fairly antisocial behavior, but if the phlorotannins oxidize (light and heat will increase the chances of this) then all our data is worthless.

The next day we were ready to take the racks of plants down and attach them to the substrates. Each rack was put in a bucket and covered with black plastic and loaded into the boat. Once we were in the water we took each rack down to the appropriate substrate and tightened some nuts to secure it, which is not always such as easy task in chilly water when your fingers decide not function anymore.

Then we took the Plexiglas down and bolted it over the substrates. We needed to tighten nuts and the cable ties over the next few days, but once all this was done the experiment was basically ready to sit for 6 weeks whilst we wait and speculate on what kind of results we will get.


No comments

Note: This forum is closed for posting.

The researchers completed their expedition in May 2004. Feel free to search this site for their archived journals and responses to questions.

The University of Alabama at Birmingham The UAB in Antarctica expedition is founded by The National Sciens Foundation
© 2004 University of Alabama at Birmingham. All rights reserved. About this site. Created by UAB Web Communications.