April 2022

April 2022 – My adventurous campaign in Serbia: collecting sediments and zooarchaeological specimens

Giulia Zampirolo (ESR 6 - Copenhagen)

My project focuses on sedimentary fish archives and diadromous taxa in the Danube region (Serbia) with the purpose of tracking the relative abundance of migratory fish over time through sedimentary DNA analyses of cores as well as the changes in population structure through aDNA analysis of fossils. Sturgeon and huchen have contracted significantly over the past century, with some species completely extinct in the Upper-Middle Danube while others are classified as highly vulnerable (IUCN Red List). The main causes of their decline are overfishing, pollution and habitat destruction; in particular the construction of The Iron Gates I and II (Djerdap I: 1972, Djerdap II: 1984, Serbia-Romania) is the main cause of disruption to their spawning run in the last century.

Fig.1 Sturgeon species in the Danube, Vassilev, M. 2006. Lower Danube – the last refuge for surviving of sturgeon fishes in the Black Sea Region (Vassilev M., 2006).

The sedimentation of the river after the construction of the two dams increased considerably with the accumulation of fine sediments for several meters in the area of the Danube Gorges and together with heavy bank modifications in the last century (JDS,2005).

The plan was to start some expeditions in the area of the Danube Gorges and upper part of the river (Vojvodina) to find the best spots to sample, but with the pandemics all the plans were suspended. In September 2021 I finally managed to undertake a first expedition in Serbia with the purpose of collecting the primary material.

Fig.2 Old Danube’s paleo-meanders, Bačka, Vojvodina region, Google Earth.

Testing the Equipment

Together with my supervisor Mikkel Winther Pedersen and an archaeologist of the area, Kristina Penezić, we targeted three main locations for the sampling of Danube’s paleo-meanders: Starčevo (Banat, Vojvodina), Magareći Mlin and Donja Branjevina (Bačka, Vojvodina). We shipped our equipment (VibraCore) from the University of Copenhagen and tested it at the site of Starčevo. Trying to push the tube into the sediment was very hard and we could only get 40 cm of core. We realised that it was not suitable for the type of soil (very tough and clayish) so we had to arrange another sampling campaign with a different drilling equipment that will take place in the coming months in collaboration with the Institute of Field and Vegetable Crops, Novi Sad, Serbia.

Testing VibraCore in Starčevo, with Mikkel Winther Pedersen and Ivana Živaljević.

Sampling an archaeological site: Vinča

Another part of the campaign included the sampling of archaeological layers of a Neolithic House at the site of Vinča, on the right side of the river, close to Belgrade (Vinča Museum). The layers are composed of three different overlying floors, one of which is burnt, with the presence of two infills.

The presence of aquatic biomarkers in some of the layers of the house could be explained as the use of bank sediment for its construction. For this reason, metagenomic analyses can reveal the presence of fish or provide additional information about the use of the resources in the environment.

This was my first experience with the sampling of an archaeological site, and what better practice to learn by doing it!

I realised how it is extremely important to avoid any kind of contamination from the upper and lower layers: changing gloves and sterilising tools very well before and after each sampling is mandatory practice. Besides it is highly suggested to take notes and document the whole area in case of modern DNA contamination.

Fig.3 A: Reconstruction of Neolithic House (Archaeological Museum in Vinča); B: preparing section for sampling; C, D: sampling archaeological layers.

Fig. 4 Exhibition "Caviar", Gallery of the Museum of Natural History in Belgrade; B,C: drilling fish bones with Ivana Živaljević.

Sampling zooarchaeological assemblages

Together with Ivana Živaljević we collected a total of 57 specimens from the Laboratory of BioArchaeology, Faculty of Philosophy, University of Belgrade.

The zooarchaeological assemblages selected comprise 8 different archaeological sites with contexts dating to Mesolithic, Neolithic, Roman and Medieval periods.

The species selected for this project include:

• Huso huso (Beluga sturgeon)

• Acipenser gueldenstaedtii (Russian sturgeon)

• Acipenser stellatus (Starry sturgeon)

• Acipenseridae indet.

• Acipenser sp.

• Hucho hucho (Danube salmon/Huchen)

This experience helped me to understand the delicate process of selection of the best specimen for DNA analysis. There is always a compromise between preserving a specimen for collection and its destruction for analyses. Especially for poor preserved sturgeon elements, this choice can be very hard to take.

“It’s your responsibility, it’s your fault that the equipment doesn’t work, you should have known that in advance”, I was repeating almost every day in my mind, feeling the main cause of failure for the campaign. But instead this was the main mistake I have made, blaming myself for things that cannot be kept under my control. Talking with other researchers in the field, I realised that arranging a sampling campaign is not an easy task and everything, even if well planned, can goes wrong during fieldwork. But the most important thing I have tried to do, as my supervisor has reminded me many times, is to keep focused on the solution. And that was beneficial for my mental strength and the project itself!

I would like to conclude this quick report thanking Ivana and Kristina, who supported my research activity in Serbia, besides I would like to send a huge thank you to Iulia and Connie who accompanied me in this adventure and made me enjoy Serbia so much: explorations on the boat, vising archaeological sites and trying delicious food was so funny and special with you!

Follow updates on Twitter: @GiuliaZampirolo

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