Maria Mazurek, Next.gazeta.pl: What is the condition of the Baltic Sea now? In recent years, there has been a lot of disturbing information about oxygen deserts and oxygen-free zones in this sea. What does it look like now?
Prof. Ph.D. Jacek Piskozub, Institute of Oceanology, Polish Academy of Sciences: Unfortunately, oxygen-free zones are increasing. Recently it turned out that it was probably for different reasons than we thought. Of course, the phenomenon itself began with eutrophication, i.e. over-fertilization result large amounts of nitrogen and phosphorus fertilizers flowing into the Baltic Sea. However, we have significantly reduced these discharges, and anaerobic zones have not decreased, in fact they are increasing. The inflows of water from the North Sea do not help much, and they have moved more to the summer period. It appears that the current state of oxygen-free zones in the Baltic Sea is mainly a direct result of atmospheric heating. The warmer atmosphere warms the surface waters of the Baltic Sea faster than those deep inside, which increases the density differences between them. To put it colloquially: it is more difficult to mix the Baltic Sea. If confirmed, it would be a direct result of global warming. As long as we heat the atmosphere, oxygen-free zones will not disappear.
So what about biological life in the Baltic Sea?
I often say that cod in the eastern Baltic Sea can no longer live because of oxygen deserts, while herring in the western Baltic Sea are too warm in winter to spawn. The area where these basic fish species occur in the Baltic Sea is decreasing. We are left with sprats and flounder near the coast.
Maybe something else will come here that will feel better in the new conditions?
Maybe, but it won't necessarily be something we eat. When we overfished – Poland also contributed to this – the large, seemingly endless cod fisheries near Newfoundland and Canada decided to ban these fisheries, contrary to expectations, the cod did not return. In their place, cuttlefish appeared. The same thing may happen in the Baltic Sea. For example, gobies and other fish that we brought from warmer seas may feel great here, but these are not the fish we eat. Ecologists and scientists often say that the Baltic Sea will always be alive, and this is true, but from the point of view of the ecosystem. From the perspective of a person who would like to have, for example, water free from cyanobacteria, so that he can swim during the holidays and eat fish at the seaside, these will be big changes. Besides, most of the fish we eat at the seaside now does not come from our catches in the Baltic Sea, except maybe flounder.
So, in short, the situation in the Baltic Sea is not improving at all?
– NO. The last HELCOM report concluded: bad in all assessed categories [HELCOM – inaczej Komisja Helsinska, międzynarodowa Komisja Ochrony Środowiska Morskiego Bałtyku – red.].
What about chemical weapons sunk to the bottom of the sea?
Obviously, there's a lot of it. Thanks to our research, it was possible to count how many of these weapons there are and where. It is much more scattered than we thought. What to do with it? There is still no decision on this matter, because there is a chance that leaving it will be less risky than moving these landfills. If we find a good mining method, without risk, we will probably have to do it someday. And there is a high risk that mustard contamination would increase during mining. Mustard bombs, after so many years at the bottom, are no longer bombs, but spots of solidified mustard gas that leaked out of them and, under the influence of cold water, transformed into a goo with a consistency resembling tar. At this point, this waste is not emitting much mustard gas, especially since it is hidden beneath the sediment. If we started moving them closer to the surface, where the water is warmer, it could end badly.
Finally, I will ask about the Institute's research vessel. Can we already say that Oceania has been saved?*
Yes, I think that, to a large extent, thanks to the media that publicized this matter, there was a sudden upheaval in the ministry. All this confusion even had an advantage – more people, I hope, learned about the research we were conducting. Suspension of financing would be a total disaster, for example we would have to pay back funds from numerous grants, including foreign ones. We cooperate, for example, with Norwegians in the Arctic, and Norway provides money for our joint research there.
*At the end of October, IO PAN scientists issued an appeal due to the suspension of funding for the “Oceania” research vessel by the Ministry of Science and Higher Education. A few days after the case was publicized However, Minister Dariusz Wieczorek allocated PLN 8 million annually for “Oceania” for the next three years. It is the only Polish research vessel that can conduct work outside the Baltic Sea.