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18 May 2018

30. We collected 30 treefrogs on a single night!!

Once again the visit to the long ditch that runs parallel to the east side of Prypiat river on the nort if the Exclusion Zone give us the best results. This area, in which we have sampled in five different localities over the three years of our “Chernobyl frogs” project is definitely a paradise for amphibians, despite being an area with medium and high radiation levels.

We started our daily routines in the lab, sampling the thirteen frogs collected the previous night near Chernobyl city in an area of low radiation levels. Work on the lab was more or less as usual. There are never two equal days on a field lab, and there are always small incidences that need to be solved on the spot. Anyway, work on the lab was good, and there were not too many frogs to deal with.

Sergey even managed to pass all the frogs through the radiometer, so we have now good measurements of radioactive dose rate from all our frogs, including these from clean areas. Actually, it tourned out that not all these frogs were completely clean from radiation, and some showed low levels of contamination. Even more interesting.

Thanks to our acquired abilities (mostly, the amazing Jean-Marc’s technique of extracting blood!!) we were also able to run successful blood analyses for 12 out of the 13 frogs. These are amazing results that will tell us a lot of details about the physiological state of all these frogs. Results so far, after a quick view, are pretty consistent, showing variability on the diverse parameters we measure, but always between reasonable limits. We need to keep on adding more data here!!

By mid afternoon all the samples were collected. With the work, cryovials have started to accumulate in our dry shipper, and we even needed to add more liquid nitrogen there. This is one of the “luxuries ” of working here, with the International Radioecology Laboratory people, we have access (although not easy access) to good amounts of liquid nitrogen in the field, essential for storing all our samples for conducting physiological and genetic analyses.

Weather forecast was not too good for the night, with chance of rain, and temperatures going down. Anyway, after our early dinner we were ready to go to the field, with the idea of visiting different locations along the east bank of the Prypiat river, in the north of the Exclusion Zone. We have worked in this area since 2016, always with success. We started our journey to this area with good vibes, although the way was not as easy as expected, and we even need to take out a rather large tree from the middle of the path!!!

Once on location, we split our group in two teams, as in some previous days. We arrived to our first locality after a drive across the middle of nowhere, going around trees and up and down bumpy fields. This route, by the way, it would be impossible to do without the navigation skills of our Ukrainian colleagues that identified and marked this track for us many months ago. Thanks!!

After stopping, Evgeny (Žénja), Pablo and I moved to the first pond, and Sergey and Jean-Marc went back to sample on different localities. Our locality was located in rather high levels of radioactive contamination, with peaks around 20-30 microSv/hour (normal, background levels are around 0.1-0.3 microSv/hour). Soon after arriving we heard our first treefrog!! After twenty minutes more treefrogs were calling in the distance and we moved in. The area was easy for orientation, with few water channels going in circle. Water level was a bit higher than ideal, although enough (just barely enough) for working and crossing from side to side of the channels. The first frogs I caught were totally on the limit, captured with one hand while the other was putting the chest waders up in order to avoid water entry. Five centimeters deeper and they would have been out of reach…

Some frogs were loyal to their name and often calling from tree branches, a meter high from the water. Not always was easy to spot them there, and twice I had to use my left hand to catch them from a crisscross of branches (both times successfully!!). Through the phone we knew that our colleagues were not successful on their first locality, but managed to collect 16 frogs on a second place in which we have worked since 2016, on mid radiation levels.

At the end, we were also able to catch 14 frogs in our place, for an amazing total of 30 for the night, including a completely new locality. That’s fantastic!!! It was a particularly good night for Sergey and me, both with 11 frogs captured 🙂 These 30 frogs will definitely give us lot of things to do in the lab…

So, the plan for today is an intensive, super intensive, session of work in the lab with these frogs (let’s see if we can finish them before the night). If weather is good (forecast of rain for the entire day), we will try to capture more frogs in mid-high contamination areas close to Belarus. Anyway, long day ahead f work, sweet!!

Working on high contamination area resulted in a daily dose rate of 15 microSv, for a total of 40 for our trip. On the way today, we saw mousse, red deer, wild boar, white-tailed eagle…