Crete experience

Posted by Marcia:

One of the first papers I read in my graduate studies was written by Frede Thingstad and titled “Utilization of N,P, and organic C by heterogrophic bateria. I. Outline of a chemostat theory with a consistent concept of ‘maintenance’ metabolism”, published in 1987 in Marine Ecology Progress Series. Well, that paper was one of a handful I read over and over, knowing that it was important and trying my hardest to grasp every aspect of it, and all the time failing to grasp it completely.

This summer I got the amazing opportunity to join Frede, and a small group of researchers from 3 countries, for a mesocosm experiment in Crete that was designed to recreate an experiment that was previously reported in Science, 2005. The title is “Nature of phosphorus limitation in the ultraoligotrophic Eastern Mediterranean”. I have never met ANYONE who has tried to repeat an experiment that has been (well) published, but then again, I have never met anyone like Frede. He told me that he just never really believed it and just had to try one more time to see if he could get the same results.

So, we met in Crete, outside of Heraklion, in a wonderful tiny village, Gournes. We worked at the Hellenic Centre for Marine Research next to the Cretaquarium. The experiment was a simple design, 6 mesocosms 1 x 3 meters deep, 3 with added P and 3 without additions, all held in a deep concrete pool that had well water flowing through it to maintain a temperature of about 25C. The mesocosms were filled with “blue” water from about a mile offshore in a gyre that is ultra-oligatrophic, which means that it doesn’t have much growing in it. The zooplankton concentrations were about 1-2 per liter! (really tiny amounts!) The experiment ran for 6 days and people were busy sampling, running all sorts of experiments. Here is a photo of Frede and the mesocosms:

Tom and I started off by arriving in Crete far ahead of our luggage, so our sampling was delayed by several days. When we finally got our equipment we discovered that zooplankton in the Mediterranean are incredibly tiny and difficult to pick (I can’t understand how marine copepods can be so tiny!!). After picking for two days, we were finally able to begin to imagine that we could tell the two dominant species apart. Then, after our minor success we tried to board the airplane back to Oslo, only to discover that Crete will not allow dryshippers to be taken off the island without more official paperwork than we could scrounge up. Oh, ok, we could get it as far as Munich, but not to Oslo. So, the zooplankton got a ride back to the Institute in a taxis while we progressed on. We have hopes of someday meeting up with our work and seeing it to completion.

Besides working, we took a day to site see. We went to Agrios Nicholaos, a small town about 50km from our base. There we walked around the “lake”, which is a freshwater lake with a narrow outlet to the sea. This lake was described to us as a “lake without a bottom” and has been studied by Jacques Costeau! I hope someday to see a utube episode of that show. Crete is an island made of limestone and is therefore karstic, and this lake is reputed to link up to another island, Santorini, via an underground cave. Who knows… What we found was that there are more fish in this one small area than we found in any other spot we looked at on Crete. There were hundreds of little minnows per square meter starting from the mouth and all the way around the edge of the lake. Then there were larger fish–I think we counted at least 4-5 different species–feeding on the minnows and each other. It was amazing. Here is a photo of the lake:

Now I am back in Oslo and enjoying a real Fall weather pattern complete with leaves turning colors and the need for warm clothes in October. I am doing work on NMR and line scanning cameras and xray fluoroscopy. In other words, a real busman’s holiday.


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