2019. Season recap

We are now on board of the Madrid-Oviedo train, the final step of our trip back home from Chernobyl. After driving from Slavutych to Kiev in the morning, we arrived to Madrid yesterday at midnight, all luggage with us, no problem with the samples. So, I thing this is a perfect time for writing a summary of our field research campaign in and around Chernobyl. Let’s go.

To be honest, before arriving to Ukraine, we had doubts about the length of our research campaign. We felt that we should have add a few more days, at least one more inside Chernobyl and one more in Slavutych. Just to play safe if the weather turned wrong, or we were unable to find amphibians at some point. This is the kind of unsettling feeling before the star of any field work, I guess… At the end, we worked for four days and nights inside Chernobyl Exclusion Zone, and another four outside, on clean areas around Slavutych. And that was enough. We managed to collect all the samples we needed for the different projects. A total of six different studies!! Let’s summarize them one by one.

First, our study on Pelophylax frogs, looking at mutation accumulation and genomic changes through time. We wanted to collected new samples of this group of frogs to compare with the samples collected in the Zone in 1987-1990, and that we have already in our lab. The main idea was to collect frogs in one of the original locations where the frogs were collected 30 years ago. We did that on the second night in Chernobyl, with a total of 23 individuals captured on a pond outside Chernobyl town. We also wanted to compare these frogs from nearby Chernobyl city, currently living under very low radioactive contamination, with frogs from a highly contaminated locality. And that’s why we went to the Azbuchyn lake (pretty close to the power plant) on our first night in Chernobyl. There, we captured 12 frogs. As a final touch, we aimed at collecting frogs from a un-contaminated locality outside the Exclusion Zone. We did that too, on our first night in Slavutych, when we captured 20 and 7 frogs on two different localities, one completely new for us. So, in total 62 frogs collected in areas with high radiation, low radiation and no-radiation. A really great group of samples!!

Our second goal was to repeat this sampling with the fire-bellied toad (Bombina bombina), another species for which we have samples going back 30 years. This is a species we didn’t had much experience with. Is clearly abundant in the Zone, as the males calls can be heard in many places on a warm night. But once in the ponds, is not always easy to locate where this small, brown frogs are actually calling. We were a bit unsure about how easy it would be to find them. At the end, we collected 5 individuals in high radiation area (Azbuchyn lake), 5 in a low radiation locality (close to Chernobyl), and another 5 near Slavutych, in an un-contaminated place. it wasn’t o difficult . We even caught some of them in daylight!! So, a total of 15 individuals to compare with the old samples, and check for genomic changes associated with radiation. Second goal accomplished.

A third goal was to perform a small experiment looking at how plastic is treefrog coloration over a short period of time. This study is linked to the one on treefrog coloration we have performed since 2017, after detecting a high number of dark frogs inside Chernobyl Exclusion Zone. Otherwise, these frogs are normally green, brilliant green. On our first night in Chernobyl we captured 14 Eastern treefrogs (Hyla orientalis). We photographed all of them, and put half individually in containers simulating a light background, and half in containers simulating dark background. After two days under these conditions we took another photograph of the frogs to evaluate color change. All went well. Let’s see now what these photos tell us.

We also managed to complete our study on treefrog coloration by adding individuals from two more localities outside the Exclusion Zone. Until now, we had good results, but only had frogs collected in two localities outside Chernobyl Exclusion Zone. We wanted to expand the number of localities and individuals for this study, in order to be more confident about the results. We finally caught 8 and 8 individuals in two localities around Slavutych in our second and third night there. That was particularly good, since the species is not very abundant, and not always easy to find, especially outside Chernobyl, where Sergey has less field experience. Another big goal achieved, and a big relief for us and this study in particular.

These treefrogs from new localities will be added to the study on genetic variation and connectivity that we are also performing with our colleague Jean-Marc Bonzom (IRSN-France). So, more individuals, and two really important localities to improve the power of this study too. Superb!!

Finally, something totally new this year was the sampling of environmental microbiome in water bodies of the area, both inside and outside Chernobyl Exclusion Zone. The idea is to use this info in two different ways. One is to add these samples to our studies of treefrog skin and gut microbiome, with all the samples collected in previous years (around 200 individuals, from 11 localities). We wanted to know how radiation (and other factors) affects the diversity and composition of the amphibian microbiome, and also how the frog microbiome is related to the microbes available in the environment. As a second stage, and by adding more localities, we wanted to expand the study to investigate how radiation, but also water variables, like water ph, conductivity, disolved matter, and landscape variables like the type of soil or vegetation, affect the diversity and composition of microbes living in aquatic environments here. We did two days of intense work in Chernobyl, sampling 16 localities there, from really high radioactive places like Azbuchyn and Hluboke lake, to clean areas of the south. Then, we added another 5 localities around Slavutych. A total of 21 localities with water, soil and sediment samples, an a full set of environmental variables to work with. This was, especially in Chernobyl, a very exhausting work, but also a great opportunity to move around the Zone by daylight, seeing the different habitats of the Zone, something that we didn’t had much chances to do in previous years when going for frogs during the night.

In summary, a total of eleven days out of home, three flights, one train trip, more than 1000 km driven (many of them either directly off-road, or in pretty damaged and bumpy roads), and many hours with our wadding boots in the middle of ponds. Now, we have ahead an equally important task, to enter all this data in our files, and analyse all this samples. We will finish some of the studies pretty quick (coloration, for example). Some others will take a little longer (environmental microbiome). For others, we will need to convince our colleagues and evaluators, to support our next application for a national research project later this year. Let’s see how it goes!!

At the end, as in all previous years, not only research was good. The great time and friendship with Sergey and Pablo, was one of the best things of these days. We had a lot of fun, we enjoyed the time capturing frogs and sampling microbiome, but also our picnics in the field, our time talking about life and the old Soviet times with Sergey, even the bumps and bumps in the roads!! Working, learning, and improving with other colleagues is one of the great things of these campaigns, no doubt. Thanks for being so great!!

I am going to finish this blog here for now. I will add more entries next time we will work in the field, or at the time we will publish a paper on this work. From now on, you can keep track of our research on Twitter, where I am pretty active at @GOrizaola.

Thanks everyone for following us during our #ChernobylFrogs19 campaign. I hope you have like it. Until next time!!

2019. Day 9 Finishing the job

Our last full day in Ukraine, and our last day in the field. Even if all our goals were achieved last night with the catch of more treefrogs in a new locality, there were still some few things to finish for us. We released all the frogs, and completed our environmental microbiome sampling by adding two more localities. We never stop working in the field!!

Early in the morning, we worked in the lab with the fire-bellied toads collected the previous morning, and the treefrogs from the night. Quick photos, measures, and tissue sampling for genetic analyses, and we were finished. Our last task in the Slavutych lab for this season.

After this, we get into the car and moved to the place were we caught the toads the previous morning for a quick release. And from this, more drive to the place were we caught the treefrogs.

With the release of the treefrogs, all amphibians caught this year were back to their original ponds. A great feeling!! It was time for sampling environmental microbiome here, the locality number twenty of our study!! Another fantastic set of samples we have collected this year 🙂

From here, we had another long drive towards the south, to reach one of the last localities visited last year, for a final round of environmental microbiome sampling. On arrival, we surprised a big male moose (Alces alces). And we get into the waders for a final time.

Everything was finally done. Twenty one localities sampled for environmental microbiome, all amphibians collected and sampled. Everything as we wanted, everything as we dreamed when planning the season from the office in Spain. It couldn’t have gone better. Such an incredible joy!!

It was time for a team photo, as in all the previous years. As always, it has been a pleasure to work with Pablo and Sergey. Amazing work done, and even better atmosphere, always positive, always with a smile in our faces, in the lab, in the ponds, jumping around off-road with the car… And learning everyday something new from Sergey and his long history of research and life in Chernobyl for the last 33 years. Our days with him, are no doubt among the highlights of our research year!!

Tomorrow it will be time in the morning to pack our things in the lab: cameras, tripods, headlamps, tubes, samples, and the like. Around noon we will say bye to Sergey, the Chornobyl Centre, and Slavutych. Until next time!! Someone will drive us to Kiev airport, where we will take a late plane to Madrid, arriving at midnight. We will have the night and following morning to enjoy Madrid and celebrate the success of the trip!!

More tomorrow, for some of the final histories of our campaign of research with Chernobyl amphibians!!

Have a good day!!

2019. Day 8 Last night at the ponds

Today we achieved something rather unusual in a field research campaign. Thanks to our work in the ponds during the morning and night, we completed all our goals for this season. Every single thing we wanted to do, is now done. In all the previous years working in Chernobyl, our campaigns were quite successful but always there was something that we didn’t managed to complete, some fewer localities sampled that we wanted, some fewer individuals… not this year. Everything is done, and we still have one day left. We can’t we happier.

During the morning, we quickly sampled the treefrogs collected the previous night. Photo, morphological measures, and a tissue sample to add to our collection of about fifteen treefrogs localities in northern Ukraine, both inside and outside Chernobyl Exclusion Zone. This work, growing year after year, has reached a really great sampling size and locality distribution, time now to get deep into population genetics!!

Around noon we went back to the car with the simple objective of releasing these treefrogs and sample environmental microbiome in this pond, and the one at which we collected 3 treefrogs and some Pelophylax (including our +150g ridibundus Beast) on a previous night.

On our way, during daylight, we were able to see where we drove the previous night, in the middle of darkness, following treefrogs calls from more than two kilometers away!! Simply amazing where Sergey is able to go with the car!!

Once in the pond, we released the frogs, collected microbiome, water parameters, and at the moment we were abou to leave… a fire-bellied toad called nearby for a few seconds. We looked at each other, smiled, and said “Ok, we need five of these, so let’s have a look just for five minutes”. Collecting these small, brown amphibians at midday, when they barely call, in a big, brown pond is almost impossible, but… Quickly Pablo found one, other called for a few seconds, a bit far. We finally spent way more than an hour under scorching sun to get the second one, but we did it. The three of us surrounding a small patch of vegetation for half an hour, for locating the toad on the very same moment we decided to leave 🙂 Two toads in the pocket!!

We drove to the other pond, released the frogs and sampled microbiome. Just moving around for sampling water parameters, Pablo saw again another toad. And then another. And another. Totally unexpectedly, we were there, at midday with the five toads we needed from outside the Exclusion Zone for our genomic analyses!! We will compare these toads with the ones collected at the Zone, and the samples we have from 1987-1990. Incredible good material!! What should have been a quick and easy one-hour visit to two ponds, ended up in a more than three-hour work, but a very important thing was done. Another big goal crossed for the campaign!!

We had four hours in Slavutych for late lunch, rest… and back to the ponds, for (probably) our last night in the field. We drove to the east of the city looking for treefrogs. Now, we only needed this species, the work with toads and Pelophylax was finished. We drove and stopped for listening, drove and stopped. No treefrogs.

In one of these places after many years listening to corncrackes (Crex crex) while collecting frogs in Ukraine, Poland, Latvia, Lithuania, Estonia… I managed to see one!! A bird just flew from my feet’s for a short move. This is a species in sharp decline all across Europe, but apparently abundant in this area. A great moment for any birdwatcher and a good start of the night!!

We drove even more across meadows, with no roads, no paths, and tall plants blocking the view from the car in some cases. We stopped in what looked like a small pond for listening. Treefrogs were there!! We jumped out of the car, waders in, and off to the water. The place was bigger than we thought, beautiful, with the perfect amount of water, not too little, not too much, enough to move around everywhere without getting too deep. Frogs were calling but not to intensively. After moving across all the pond, we finally managed to catch eight males. A fantastic catch to complete all the studies with this species, the genetic and coloration ones in particular. We leaved the pond tired after a very long day, but with a huge smile in our face.

Now, everything is done. All the Pelophylax, fire-bellied toads, and treefrogs that we wanted to catch, are caught and sampled. All the localities we needed to complete our studies, sampled too. What an amazing feeling. Everything has been so good this time, it’s almost unbelievable. Of course, we are more than exhausted after seven consecutive days of 4-5 hours sleep, and about 16 hours expended everyday in the ponds, the lab, or jumping in the car from one place to the other. But we are happy, incredibly happy!!

Today, we will quickly sampled these last treefrogs, and… off to the ponds again. Don’t think we are finished 🙂 We will release the treefrogs and sample environmental microbiome on the pond in the morning. For the afternoon, we will drive far away, south of the city, to sample microbiome at one of the localities we visited last year. And that should be all. Back in Slavutych in late afternoon for relaxed dinner. This will be our last full day in Ukraine. Tomorrow, on the afternoon, we will fly to Madrid. Back to Spain, bags full of samples, and heads full of great memories. Let’s go for a last day with more ponds, beautiful landscapes, and a bit of work.

More tomorrow. Enjoy the day!!

2019. Day 7 Golden treefrogs

It wasn’t easy, but we ended the night with ten Eastern treefrogs (Hyla orientalis) collected in a new locality near Slavutych. These frogs are extremely important in order to complete and give power to our coloration analyses, since until now we only had two localities outside Chernobyl Exclusion Zone. Again, a long and exhausting night, but a really good one!!

First thing we did in the day (after a fantastic breakfast of orange juice, cappuccino and Benedict eggs!!) was going to the lab for measure, photograph, and took a sample from the Pelophylax frogs collected the previous night. We did all this at the labs of the Chornobyl Research Centre for Nuclear Safety, Radioactive Waste and Radioecology. Our colleague Sergey Gaschak is the deputy head of the Centre and the director of the Radioecology lab. Great facilities with fantastic labs.

Among the frogs we sampled was a huge marsh frog (Pelophylax ridibundus), the biggest frog we have collected in all these years. A massive female of 154 grams!! After sampling her, we had to take some photos as a memory, no doubt.

This time we have a sampling protocol much more simpler than in previous years. We mainly took a photo of each individual, measure the mass, length, width and depth of each frog, and took a phalanx sample for the genomic analyses. In previous years things were much more complicated, since we sampled a lot of different tissues from each individual for genetic and physiological analyses, something that took us about half an hour per frog. Now, in a little more than an hour all the 30 frogs were ready. This also allows us to have time to take some good quality, profile photos of our study species, the kind of photos that later on are fantastic when given talks, presentations, or for working with the media.

“The beast”. Female marsh frog (Pelophylax ridibundus).

Male Centroeuropean green frog (Pelophylax lessonae)

After lunch, we went back to the road. First we released all the frogs collected in the first locality we visited last night. All back to their original pond, as every frog this year. Then, we started to drive around the southwest of Slavutych looking for potential good areas to visit during the night. We find some, with some Pelophylax activity, and many more pretty dry after a spring with little rain in the area.

During this drive we had the chanc to see some wildlife too, including many birds linked to meadow habitats like red-backed shrikes (Lanius collurio), grey partridges (Perdix perdix), white storks (Ciconia ciconia). We also saw, and sometimes moved out of the road, many European pond turtle(Emys orbicularis).


We finally went back to Slavutych for dinner, and back to the car again at 8:30PM. Really a non-stop schedule we have here… We first drive to some of the localities we visited after lunch. No fire-bellied toads calling, no treefrogs. We waited and waited in some localities. Nothing. Not a single amphibian, apart from the Pelophylax that we don’t need anymore.

We moved to other area, closer to the Dniepper river and the Belarusian border. There, we heard treefrogs, finally!! But they were far, far away, in an area of sandy meadows and water channels. Thanks to Sergey’s knowledge of the area, we drove back, making a big circle trying to get closer to the frogs. Everytime we stopped the frogs continued to be far away. It looks impossible to get closer to them, honestly. Finally, thanks again to the driving skills of Sergey and the sturdy “Great Wall” Chinese 4×4, we went straight trough the unknown meadows. Trying to avoid water channels, holes, or whatever in the middle of the absolute darkness. Finally, we arrived close to where the treefrog were calling!! We put on the waders and moved quickly to the pond. Treefrog they were many, but extremely well hidden. It took as one and a half hours to catch ten. But these ten are extremely important, pure go,d in terms of research. They will allow us to have a much more balanced design in our coloration study between contaminated and non-contaminated localities. On the way back to the car, Pablo couldn’t hide a big smile thinking about sampling size, statistic power, and all these things that a researcher thinks about in the field 🙂


Today in the morning we will sample and photograph all these treefrogs, and then we will back into the car releasing them, and start sampling microbiome in the last two localities where we collected frogs. Another great addition to our studies here!! During the night, we will be back to the ponds trying to get these additional five fire-bellied toads and more treefrogs. This may be our last night in the field for this campaign, since we finally leave on Tuesday and will not have much time for sampling that day if we go to the field Monday night. But, let’s see…

We start our day here now. More tomorrow. Enjoy the Sunday!!

2019. Day 6 Out of the Zone, but with more frogs

Today we left Chernobyl Exclusion Zone to continue our fieldwork in uncontaminated areas around Slavutych. At the end of the night we visited several places and collected 30 new Pelophylax frogs and 3 treefrogs. Everything continues to be really good this year!!

Early in the morning we packed all our stuff at the hotel and the Chernobyl lab, at the same time that Sergey cleaned the car in order to remove any possible traces of radiation before leaving the Zone. Radioactive particles can accumulate in a car just by driving around the Zone and get pieces of vegetation stacked in the front of the car, for example. Since the previous day we drove quite a lot all across Chernobyl, this was a quite important task, so we don’t “export” radiation outside the Zone.

We left our great Chernobyl lab around 10AM, with the car fully loaded with all our stuff, and the field gear we will need to use in Slavutych. When we arrived at the Exclusion Zone check point we faced one of the realities of the Zone right now. A long, very long queue of vans and buses, full of tourists ready to enter the Zone. This is becoming a really big business, no doubt.

All radiation checkings were fine, for us and the car. And at 10:30AM we were out of the Zone. We have spent a total of four days inside the Zone, less than in previous years. But four intense and very successful days!!

After leaving the Zone, we continued our long trip to Slavutych. This is a city, created right after the accident in a location were just a train stop existed. It was built to accommodate most of the people evacuated from the Zone. It is about 50 km in straight line from Chernobyl, crossing a corner of Belarus, something that is not possible for us (too complicated paperwork). So, we needed to drive back south to the outskirts of Kiev, and then back north again. In total, 300km, and around four and a half hours!! We even had our “small” problem on the road. The bottom plate of the car fell down in the middle of nowhere. Too much off-road drive and bumps on the last days… It was time for Sergey to put on one of the white Dyvek protection suits, the first time I’ve seen Sergey that way 🙂 With handy skills and some plastic straps, everything was fixed quite quickly. And we continued the road to Slavutych.

We arrived in town at around 2:30 PM, to a fantastic hotel in the middle of the city (25.000 inhabitants). During this weekend the city celebrates its annual festivities, so we were amazed to see all the center full of tents of small local shop, grills and outdoor restaurants, music stages, and wonderful attractions for the young ones. A great atmosphere everywhere!!

In Slavutych, we are also back to a place where we can move freely, and enjoy some of the restaurants (“Old Tallinn” in particular). So, we had a very late and relaxed lunch on a terrace, under perfect weather. Not bad, at all.

At dusk, it was time to head to the field again. We drove around 20km out of town to a place known by Sergey, with ponds and streams. Waiting for darkness, we sampled environmental microbiome here too. More points for our study, more data!! We didn’t hear any treefrogs, any fire-bellied toads, but quite a few Pelophylax. It was quick and easy to catch more than twenty of them, really abundant species everywhere.

After this, we started to move around looking for other places with amphibians. We drove around and around, stopping in several places for listening. We didn’t find much. It was a bit colder than the nights before. We only heard occasional Pelophylax , but plenty on corncrakes (Crex crex), a bird in sharp decline across Europe, that seems pretty abundant here. We ended up in the last locality we visited last year, looking for the fire-bellied toads. We heard not a single one, but plenty of Pelophylax were calling and even a few treefrogs!! At the end, we collected around ten Pelophylax, we no longer need more, and three treefrogs for completing our coloration studies. We even caught one pair of frogs in amplexus, a huge female quite likely Pelophylax ridibundus, with a P. esculentus male. On arrival at the Slavutych lab, we leave them together, so let’s see if we can have genomic samples of the male, female and eggs!!

The plan for today is do a bit of work in the lab with these frogs in the morning (it should we quick and easy). Enjoy the nice food and the city atmosphere. And it will be time on the afternoon to move a bit far from the city looking for our five fire-bellied toads, and more treefrogs localities. For Sergey, this is an area much unknown than Chernobyl, so finding good places is a bit more challenging, so let’s see. Anyway, we can’t complain about anything this year, everything has been more than perfect so far!!

More info tomorrow!! Have a good day!!

2019. Day 5 Microbes everywhere

Today we sampled environmental microbiome all around Chernobyl Exclusion Zone. We managed to visit and sample ten more localities, for a total of sixteen in two days. Exhausting, but amazing day.

First thing we did was to photograph again the treefrogs in our coloration experiment to measure their color variation over a 48-hour period. Then, we prepare all the amphibians for their release in the original localities, and went off to the road

We went first to the Chernobyl pond, where we released all the Pelophylax and fire-bellied toads collected on day 3. This was also our first locality for the day for environmental microbiome sampling, so we collect water, sediment and soil samples, together with information on radiation levels and water characteristics.

Then, we encountered something unexpected. The internal check point that gives access to the nuclear power plant and Prypiat was closed. No information about why (possible military exercises), or when it will be open again, and a line of ten cars and trucks. We were in our way to the power plant and Azbuchyn lake, so in order to not waist time, we changed plans. We moved a long way to the southwestern side of the Exclusion Zone, to the locality we sampled first in 2017 (our locality 7).

Locality 7, Chernobyl Exclusion Zone

We collected all our samples there, and had lunch on site, in our “cozy” picnic chairs and table. After this moment of relax, we started a non-stop, 8-hour drive across all corners of the western side of the Exclusion Zone, collecting environmental microbiome samples everywhere.

After visiting old localities in which we have collected treefrogs since 2016 (numbers like 8, 16…), and some that we visited but without catching frogs, we finally arrived to Azbuchyn lake at around 7PM. We have always visited this place during the night. This is the very first locality where I started catching treefrogs in Chernobyl back in May 2016. I called that first blog entry “At the shadow of Reactor 4” or something similar. This time, it was possible to see how close is the reactor (with the new confinement building).Pretty. close. Radiation levels here were also pretty high, around 20 microSv/h in the water and much more in the soil.

Azbuchyn lake, with the reactor 4 in the background, Chernobyl

When we finished this locality (already eight for the day) light was going down fast, and we were really tired. So we needed to choose if going for one more nearby, two more far away, or call it the day and stop. As you can image, it took us a couple of seconds to decide to go for two more!! So, we drove all the way from the power plant to the south of the Exclusion Zone, around the Uzh River, for localities 5 and 6, the last two sampled in 2016, and the last two we sampled this time for environmental microbiome.

So, we finished a 11-hour drive through the Zone, about 180 kilometers of small and bumpy roads, with ten amazing localities sampled for our study of the factors that affect the diversity and composition of the microbes that live in aquatic areas of Chernobyl Exclusion Zone.

This was our last day in the Zone for this trip. Tomorrow, it will be time in the morning for packing everything, pass the radiation control at the exit check point (ourselves, our equipment, and the car), and move out of the Exclusion Zone, towards Slavutych. This is the city where the Chornobyl Research Centre has it’s central offices and labs, and a place we visited already last year. This will be the second part of our work in Ukraine, now in clean, non-contaminated areas, not affected by the nuclear accident. The goals, many, again. First, to catch a few Pelophylax frogs and fire-bellied toads for the genomic analyses, in order to compare this individuals from clean localities with the ones from Chernobyl 2019 and 1987-1990. We will also collect environmental microbiome samples, to have references from uncontaminated locations. And finally, we will try to capture treefrogs (Hyla orientalis) in new localities in order to expand our study on coloration. Let’s see how it goes!!

Yesterday, we drive quite fast from place to place, and was a rather warm day, so we didn’t saw much wildlife. Anyway, we encountered one young Przewalski horse, red and roe deer, hare, and many birds including black woodpecker (new for the year).

By the way, when I arrived to the hotel, tired and dirty, I found that my article published a month ago at The Conversation (Spanish and English versions) had reached one million reads (1,000,000!!). This is amazing, mind blowing, and a perfect way (together with a warm shower) to finish the day. Let’s see what happens today, slightly cloudy and fresh, so not perfect for warm-loving frogs, but will see.

Have a good day!!

2019. Day 4 Microbes of the left bank

A fantastic day in Chernobyl, with some lab work in the morning and the entire afternoon sampling environmental microbiome in the left bank of the Prypiat river.

Left to right: Germán Orizaola, Sergey Gaschak and Pablo Burraco at Vershyna lake, Chernobyl.

We started our day in the lab, measuring and sampling the fire-bellied toads and the Pelophylax waterfrogs that we collected the previous night at the pond near Chernobyl city. That was a quick and easy job, so we were finished by noon. We had time to prepare all the material for going sampling environmental microbiome during the afternoon, and for a quick lunch in the lab.

After lunch, we moved to the Eastern side of the Exclusion Zone in order to collected samples for a study of the factors that affect the diversity and composition of the microbes that live in the water bodies of Chernobyl. This study will cover not only these places in which we have collected amphibians the previous years, but also some additional localities, so we can have a good idea of the effects that radiation and other environmental factors have on the microbiome of these places.

We drove through the ditch that goes south to north of this place almost to the border with Belarus. Our first locality was one we visited the last day of sampling in 2017, a beautiful set of ponds with plenty of water iris in full bloom. I am used to visit all these places during night or late afternoon, so going there in full daylight was a fantastic experience. This is an area that maintains in general mid to high radiation levels, but also a beautiful landscape mixing marshes, water channels, and forest.

We sampled a total of six localities in this area. Sergey was on charge of assessing radiation levels and collect pond sediment samples, Pablo measured different water parameters (pH, temperature, conductivity, disolved material), and I was in charge of going around with the swabs and vials to collect the microbiome samples. We did this at three different points on each locality to have a good representation of the microbes of each place. We were fast, it was all pretty well organized!!

Among the places we sampled were the Hluboke and Vershyna lakes two places with very high radiation levels. At Hluboke we took some of the samples in an area with radiation levels of 150 microSv/h. Just to remember, normal (background) radiation levels are on around 0.2 microSv/h. So, yes pretty high radiation levels. Anyway, while sampling this place we were surrounded by black terns, a pair of mute swans, and the songs of cuckoos, reed warblers and many more birds.

Hluboke lake, Chernobyl.

Vershyna lake, where we collected treefrogs last year, is other place with high radiation levels (around 25 microSv/h), and a rather difficult access, driving off-road through forest and meadows. It was remarkable to see in this place the advance of the forest, with plenty of young oaks and birches just one meter tall growing in old meadows. Changing landscape in front of our eyes.

Vershyna lake, Chernobyl.

After quite some intense work, we sampled six localities in this area, a very good start for this new project. So, it was time for dinner in the field. Thanks to Sergey, we organized our picnic table and chairs and add a wonderful dinner in the middle of Chernobyl to finish the day.

It was also a nice day for spotting wildlife. On our driver through the left bank we saw among the mammals: a big wild boar, roe deer, a red squirrel, hares, and at one place dung with the look of a big cow, maybe from an European bison? Among the birds, we saw black stork, black grouse, honey buzzard, swans, black terns, golden orioles, cuckoos, reed warblers … and more.

Today, we will took some quick photos of the treefrogs to finish our coloration experiment, and off for a full day in the field. The first two stops, at the Azbuchyn lake and Chernobyl pond to release all the collected frogs, and sample environmental microbiome. Then, we will drive all across the central and south areas of the Exclusion Zone for more microbiome sampling. Let’s see if we can sample 10-12 more localities. Today again, it will be time for lunch and dinner “al fresco”. This will be also our last full day at the Exclusion Zone, since on Friday we will move outside he Zone, to Slavutych, to sample in clean, uncontaminated localities.

More tomorrow. Thanks for following our Chernobyl histories!!

2019. Day 3 New frogs from old locations

On our second night of field work we keep with the good luck and collected all the frogs we needed from the old locations inside the Chernobyl Exclusion Zone where they were collected back in 1987.

We started the day in the lab checking all the frogs collected during our first night of work in the Zone. This year the sampling is pretty easy compared with previous seasons in which we collected multiple tissue samples from each individual, so things were fast and easy. First thing we did was to set up our small experiment to look for coloration plasticity in the treefrogs. So, every frogs was photographed and put in a container either with dark or light background. One day later we will take another photo to estimated if coloration has changed with time, and as a consequence of background color. For now, frogs are quiet in their containers at the lab.

Then, we moved to work with the fire-bellied toads (Bombina bombina) taking a small sample from a feet phalanx of the five toads collected during the night in the Azbuchyn lake. This will allow us to compare, at the genomic level, these frogs with frogs collected in the Zone 30 years ago, right after the accident.

Finally, we worked with the other species from which we have old samples, the waterfrogs of the Pelophylax esculentus group. These are a rather complex group of three very similar species, not easy to differentiate at all. So, first thing we did was to take se real photos of their morphology, especially their feet (metatarsal) tubercles. After a quick email check with our colleague and expert on this group, Glib Mazepa (University of Lausanne, Switzerland) we confirmed that all were from the species we wanted, the hybrid Edible frog,.

We also collected a phalanx from these frogs, and all the sampling was finished. Quick and easy from once. So we had time to take good photos in the lab from some of the individuals. These photos that later on are just perfect when given a talk, or asked from a journal for a cover image. Let’s see how many of them appear somewhere in print 🙂

After some time in the hotel to re o es a bit of the little hours of sleep, and an early dinner, we where back to the lab and ready for another night of fieldwork. This time, we went for a locality close to Chernobyl city, in an area with low radiation levels, when we already collected treefrogs last year, and researches collected amphibians back in 1987-1990. Last year it was an easy place, wiijust the right amount of water and plenty of easy frogs to catch. It wasn’t the same this years. The are was a bit overgrown by reeds and had plenty of water, which made frog catching quite challenging. After more than an hour of fighting our way through the reeds and some areas with water level a bit too high we ended on a pond just full of waterfrogs. So, finally we managed to caught 23 individuals. But no fire-bellied toads or treefrogs on sight.

So, we went back to the car, and walk around the area following the distant calls of the fire-bellied toads. After some time walking in the dark, we arrived at a nice pond where the toads were active. There, it was quite challenging first to locate the calling males, and then to catch them before they moved away and deep into the water. So, it took more than an hour to catch the five individuals we needed, but we finally did it.

This morning, it will be time to sample of these individuals, and check the treefrogs of the coloration experiment. Let’s see if we can do this fast. With all these frogs, we don’t need any additional amphibians from the Exclusion Zone this time. The idea now is to focus on sampling environmental microbiome in all the places we have visited since 2026, to have an idea of how the amphibian microbiome is affected by the environmental microbiome, but also to understand the factors (other than radiation) that affecte the diversity and composition of the microbiome in the ponds and lakes of the Exclusion Zone. That means that today afternoon and tomorrow it will be time for us to move around the Zone, from pond to pond sampling waster, soil and sediment microbiome. Really looking forward to mi e through the Zone during daylight!!

We didn’t move much yesterday, but enough to see a group of 3 Przewalski horses (young stallions) near Chernobyl city, and a red fox.

Let’s see how it goes today. Still warm, but with chances of rain. More tomorrow!!

2019. Day 2 Great radioactive amphibians

First night of fieldwork in Chernobyl and we managed to get a fantastic catch of the three amphibians we needed. Almost perfect, not bad for a start!!

We started the day in Kiev where our colleague Sergey Gaschak picked up us in the morning for a 2-hour drive to Chernobyl Exclusion Zone. We arrived at the check point at midday, and stopped for quite some paperwork. We are not the regular tourist that enter the Zone, so we need more, much more papers and permits. Permits for staying here for five days, permits for moving through the Zone by night, permits to catch frogs, permits to transport frogs… Still, most of the nights when we stopped at the internal check points the question we get there is often: catching frogs? for eating, right?

Once in the Zone, our first stop was at our well known hotel in Chernobyl city, where we got exactly the same two big rooms as in the previous two years (two bed room, living room with tv, additional office room, bathroom… and WiFi of course!!). After a quick stop there, we headed to our lab in Chernobyl to leave all the research material and start preparing the containers for a small test of color plasticity we want to do with treefrogs this year.

Pablo prepared twenty containers, ten of each from a different background (light or dark) to check in treefrog skin coloration change over short time periods or not, as a complementary test of the coloration studies we have done on the previous two years.

Then, after some time in the hotel and a quick dinner at the other nearby hotel, we put all our things on our big car and move to our study area for the night. As usual, we choose to work the first night in one of the more radioactive contaminated places on Earth… the Azbuchyn lake. This area of marshes, ditches and old river sections is just 1km from the Chernobyl Nuclear Power Plant. So, we passed by the plant, around the new confinement building put in place in 2016 over the reactor 4. All night we caught frogs with the red lights of the power plant in the distance.

As soon as we stopped the car, we heard plenty of treefrogs (Hyla orientalis) calling around the places, also fire-bellied toads (Bombina bombina) and some waterfrogs (Pelophylax sp.). Good sign. Sergey moved to one side of the ditch, Pablo and I moved to the other side. The area had much less water than other years after a short winter and very dry spring. We moved to a small pond were several treefrogs and toads were calling. After just a few minutes there we caught five fired-bellied toads, all we needed for the species in this place. Really easy, unexpectedly easy. We focused then on the treefrogs, calling from quite well hidden places. After more than one hour in there, me managed to catch six males, quite ok. We moved across the marshes looking for waterfrogs, when we saw Sergey’s headlamp light in the distance. We approached to check with Sergey and see what has I caught. Seven treefrogs and two waterfrogs. Great!! We just needed a few treefrogs more, and specially more waterfrogs. So, we mi Ed back to the water.

After another hour moving around, Pablo and I found a great place where we caught ten more waterfrogs. Sergey returned with one more treefrogs, and being 1AM we called for the night.

Three hours for a total of 12 waterfrogs, 14 treefrogs and 5 fire-bellied toads. A pretty good night!! Just a few more treefrogs andar would have been perfect.

So, the plan for today is first to set up our coloration experiment with the treefrogs by measuring and photographing all the individuals and put them in either a dark or light container. One day later we will photograph then again to assess color variation. We will took a sample from the toads for genomic analyses (a falange). A small finally, we will assess the species of the waterfrogs (Pelophylax esculentus, or P. ridibundus, or P. lessonae), measure and photograph them, and took a sample for our genomic studies. This should take us the entire morning. On the afternoon, we will put toads and waterfrogs back in their ponds, and start our environmental microbiome sampling in water bodies nearby.

During the night we will be back in the water for more frog catching, this time in a pond near Chernobyl city, when we already sampled last year, and from where we have frog samples collected in 1987-1990. Similar goals as last night, five toads, a bunch of waterfrogs, and just a few more treefrogs for the coloration experiment. Sounds pretty ok, let’s see how it goes!!

Not a lot on wildlife seen today, since we moved across areas with high human activity, but still we saw three red deers by one internal checkpoint, and Sergey scared four moose in one of the ponds.

More tomorrow!!

2019. Day 1 Asturias to Kiev

Finally, we are in Ukraine, ready for the start of our field work campaign in Chernobyl.

Early on Sunday, we flew from Asturias to Barcelona, and then took a second flight to Kiev, where we landed on the afternoon. No problems this time with our equipment, everything arrived, nothing lost in transit (as in previous years), nothing retained by customs. So, after getting some Ukrainian cash and SIM cards for our phones, we headed to our clasic first stop, the Boryspil Airport Hotel. First step completed.

Today is when everything starts. Our colleague, Sergey Gaschak will pick up us at the hotel in the morning and we will drive directly to the Exclusion Zone. We will have time to settle at our hostel in Chernobyl city, and prepare some things in the lab. All ready for the first night of frog catching. The weather looks perfect, sunny and earm, ideal for all the warm-loving species that are our objective. The plan for tonight is to go to the Azbuchyn lake, an area close to the nuclear power plant that we have visited every year since 2016. This area of marshes close to the Prypiat River is full of amphibians.

Our goal is to catch around 30 waterfrogs (Pelophylax esculentus + P. lessonae) for our study on genomic change and mutation accumulation using the old samples collected in 1987-1990 tat we have in the lab thanks to Glib Mazepa and Spartak Litvinchuck. Later in the lab, during the morning, we will identify the species (something tricky in this hybrid group) and took a sample for the analyses. On top of that, we would like to capture about 5 fire-bellied toads (Bombina bombina) for similar analyses, since we also have old samples from this species. And, finally, we would try to catch 10-20 Eastern treefrogs (Hyla orientalis) for a small test of color variation/plasticity to complement the coloration analyses we have done on previous years.

A pretty ambitious plan, with lot of sampling from multiple species, but we know that these species are pretty abundant in this place, so let’s see…

First of all, going for breakfast in our Kiev Zhotel and wait for Sergey for the 2-3 hour trip to the Exclusion Zone. Entry checking and let’s everything starts!!

With our Ukrainian SIM cards we will be able to send “live” pictures from the field through Twitter, so keep an eye there st the hashtag #ChernobylFrogs19. Let’s wait for what the night brings us!!