What are “golden algae”? Expert: This is the “fingerprint” of the culprit of algae

In the study of water samples from the Odra River, we unequivocally found the presence of Prymnesium parvum algae. The amounts are enormous, several dozen milligrams per liter – said Grzegorz Dietrich, director of IRŚ. The chemical parameters of the water also indicate the activity of algae – added Ryszard Szetela from Wrocław University of Science and Technology. What are “golden algae”?

The director of the Inland Fisheries Institute (IRŚ) reported during a Friday press conference that on August 11 he made a grassroots decision to send research groups to the river near Słubice. On August 12, water samples were taken.

As he said, the deputy director of the Institute, Agnieszka Napórkowska-Krzebietke, initially identified on Friday under the microscope that “there are some microalgae”. Scientists, however, needed to confirm these attempts. They “flipped” them to the so-called filters, tissue paper.

We have stated unequivocally that it is a species of Prymnesium parvum. The quantities that have been available are enormous. This is a massive algae bloom. These are not standard amounts; are several dozen milligrams per liter Dr. Dietrich said. We had a literally golden image on these filters. These enormous amounts of algae dominated the water.

The identified algae are microorganisms, the so-called golden algae, the bloom of which can cause the appearance of toxins that are deadly to fish and mussels.

He stressed that the research showed similar results from the sister German institute. We have confirmation that they also found this type of algae in large amounts, the so-called blooming – reported the director of the IRŚ.
We also find, the director continued, that the fish that escaped from this threat hid in ports are a valuable resource for future restoration of the population. Our goal is to save the surviving fish. Because it’s not that if these fish die, we can recreate them from another river, take these fish and stock the Odra with other fish here. These are fish that have adapted over generations to specific conditions – Dietrich described.

He announced further research: algae toxicity analysis. The samples have already been sent to universities, they will also go to independent laboratories, e.g. in Vienna.

I would like to emphasize that we are not politicized in any way. We have the full government support for our activities. The samples are delivered to us at an express pace and we have the possibility of obtaining financing for ad hoc activities – noted the director of the IRŚ.

Golden algae is an alga that photosynthesize and has the ability to produce toxins – reminded dr hab. Ryszard Szetela from the Faculty of Environmental Engineering at the Wrocław University of Technology.

He indicated that the activity of algae and the biological processes taking place in the waters of the Oder are evidenced by changes in the parameters of river water, coming from the measuring station in Frankfurt, Germany (at the height of Słubice). This station continuously measures the water quality in the Odra River, including oxygen concentration and water pH (i.e. its pH). The professor analyzed the compilation of these data for one month.

Especially changes in two parameters: oxygen concentration and water reaction – he explained – are like a “showpiece” of algae and testify to their activity: photosynthesis and bloom.

As for the oxygen concentration in water, before August 7 it was about 8 grams per cubic meter and it fluctuated slightly in the daily rhythm. On the other hand, on August 7, there was a dramatic jump in oxygen concentration – even up to 12 grams per cubic meter – reported the professor.

Where did this oxygen come from? From algae activity as a result of blooms he concluded.

In his opinion, the nature of the changes also proves the presence of algae. During the day, when in the presence of sunlight, algae carry out photosynthesis – the concentration of oxygen dissolved in the water increases, and at night it decreases. This is still the case today – and it is related to the continuous production of oxygen in the place where the measurement is carried out – He said.

The scientist ruled out the existence of any other source of “additional” oxygen found in the water. It is not possible that somewhere (into the water – ed.) Something was dumped that could be an additional source of oxygen, e.g. hydrogen peroxide – because this oxygen would escape. (…) [Wzrost stężenia tlenu] this is the effect of the algae’s constant oxygen production at this point – said the scientist at the conference.

The presence of algae is also supported by the change in the pH of the water in the section where the measurements were carried out. The pH of the water depends largely on the amount of dissolved carbon in it (also in the form of carbon dioxide, i.e. CO2). Normally, the pH of the water is around 8, but on August 7 – as the professor reports – there was a jump in pH to 9-9.5.

“The pH behaves in such a way that it rises during the day and decreases at night. This mechanism is the ‘fingerprint’ of the activity of the photosynthetic algae: the algae – by multiplying – absorb CO2 from the water, and therefore in the water there is a pH shift towards alkaline (alkaline – ed.). During the day the pH rises – because then CO2 is bound; at night – it drops because CO2 is released by the algae that guide respiration – he said.

The professor added that the water reaction (pH value) changes in a similar rhythm as the oxygen concentration: during the day it increases, at night – it decreases. This is the “fingerprint” of the culprit of algae – the perpetrators of this phenomenon – he argued. Undoubtedly, the problem of high oxygen concentration and the pH in the range that we observe at this measuring point are very certain – these are images of algae activity that are multiplying en masse.

The professor from Wroclaw University of Science and Technology pointed to an additional parameter – the concentration of nitrates, which changed in the observed period: there was a sudden, abrupt drop. Nitrates are compounds taken up by algae as a source of nitrogen.
As he explained, when the water becomes more and more alkaline (its pH increases), then – from the nitrogen compounds contained in it (i.e. ammonium nitrogen), ammonia (NH3) is formed, very toxic to fish, even at a low concentration: fractions of a milligram per liter.

In addition to the toxins identified by the Inland Fisheries Institute as the direct cause of the toxicity, this ammonia resulting from photosynthesis contributes to this. the professor was saying. He stated that it is difficult to assess the scale of the problem related to the formation of ammonia, because the ammonia nitrogen concentration is not measured at the above-mentioned measuring station.

But the mechanism is beyond question – he stressed. There are countries in the world where wastewater treatment plants do not require nitrification (i.e. removal of nitrogen fertilizer) in winter, when algae blooms do not occur. And in the summer there are very strict standards, precisely because of the toxicity of ammonium nitrogen.

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