Is a new blue algae (cyanobacteria) accidentally discovered in the Sea of Galilee an invasive species that may harm the natural environment? Or is it actually a discovery that will enrich the ecosystem unique to the region? Israeli researchers are trying to crack the mystery
In August 2020, Dr. Tamar Zahari, a senior researcher at the Kinneret Research Laboratory at the Seas and Lakes Research Institute in Israel, paddled a kayak in the Kinneret. Suddenly, she noticed something she didn't know before - a plant of the species Common reed with a strange cover on it. She cut off a small piece of it and put it in a bottle and took it to the lab for testing. There she realized that it was a species of cyanobacteria (also known as blue algae, although they are not algae at all, but bacteria that carry out photosynthesis), which covers the barrel, a species that has never been observed or reported in Israel and is called by its scientific name Gloeotrichia pisum. Since the species does not have a Hebrew name, they chose to call it simply Galiotrichia.
This different find in the Kinneret landscape has aroused the curiosity of other researchers from the Kinneret Research Laboratory and even suspicions that it is a new invasive species. "I have been researching in the Sea of Galilee for about 30 years and am responsible for monitoring the algae in the sea, and I have never seen a phenomenon similar to that of a species that is found in the Sea of Galilee in huge quantities and that we did not know about," says Zohari. "For research on Gliotrichia There was no formal and budgeted source of funding, but the topic intrigued all of us in the lab. This is a team that is mostly made up of female researchers and each one chose to research a different field related to gliotrichia. We are still in the research process and every time we check and discover something new."
Toxic rash
As mentioned, the Gliotrichia belongs to the cyanobacteria (cyanobacteria) system, one of the most ancient creatures on earth, created before About 3 billion years. The cyanobacteria belong to the bacterial kingdom, but use chlorophyll, a pigment also found in algae and the land plants that evolved later, to produce sugars from carbon dioxide and sunlight in the process of photosynthesis. Thus, the Blues changed About 2.4 billion years ago the composition of the atmosphere that was devoid of oxygen, and enabled the development of life based on breathing oxygen as we know it today.
Blueberries are very adaptable and have the ability to thrive even in extreme conditions. Not only that, when the conditions are very favorable (temperature, light and abundance of nutrients) the bluefish produce dense populations that in some cases concentrate at the water's surface and create Floating surfaces (superficial). Such a spread of cyanosis sometimes also produces Bloom shows So thick that they look like a thick layer of slimy slime on the surface of the water.
Such a blueberry can endanger the animals and humans who come into direct contact with it, because some blueberry produce toxins. it's aboutTwo groups of different toxins: those that damage the nervous system (Neurotoxins) and those that damage the liver (The hepatotoxins). Exposure to these toxins due to drinking the water, their contact with the skin and even breathing the spray of the waves in the same area where there is a toxic bloom of cyanosis can lead to multi-system damage and even death among living beings in general and humans in particular.
The events of the rash of the blue flowers have been known in the Sea of Galilee since the 70s of the last century, but the intensity of the blooms and their frequency are On a clear upward trend since the 90s, this is due to pressures arising from human activity, such as a change in the flow regime, an increase in the concentration of fertilizers and organic substances that find their way into it, as well as climate change and its effects on water temperature, salinity and acidity.
Survey around Kinneret and laboratory tests
In order to obtain more information about the Gliotrichia found in the Sea of Galilee, the researchers decided to carry out a survey around the Sea of Galilee in order to identify additional locations where Hatza is found. They discovered that the Gliotrichia mainly inhabits the lower part near the bottom of the common reed stems and is hardly found in the upper part near the water surface of the stems. They also saw that large colonies of Galiotrichia are found mainly in the southern part of the Kinneret and a little in the northern part.
"We estimate that this is a new species that arrived in the Kinneret only recently. It seems to be limited for the time being to the southern area of the Kinneret, but it is possible that over time it will also spread to the northern area," says Zahari. "It is possible that we contract an invasive species during the process of its spread in the habitat. Invasive microalgae may reach the Sea of Galilee in different ways, such as by the feet of birds, or attached to vessels."
An invasive species takes over a habitat
"Another interesting thing we saw is that during the last winter most of the flooded reed vegetation in the Sea of Galilee disappeared from the landscape following storms that uprooted the plants. They floated, rotted, drifted and piled up on the shores or alternatively sank to the bottom of the lake. On the other hand, we continued to find the Gliotrichia colonies also on the dead reed stems that were plucked from the bottom of the lake. In fact, the gliotrichia does not disappear completely even though its habitat (the reed) changes. It maintains a sufficient density of population, which will allow it to continue to develop and spread if suitable conditions are found."
In addition to the extensive survey they carried out in Kinneret, the researchers continued to examine the characteristics of the new species in the laboratory as well. Prof. Assaf Soknik, together with his research assistant Dithi Wiener-Mucini, the experts on blue-green algae toxins, found out if this species produces toxins, this is to find out if it already has negative effects on the water quality in the Sea of Galilee. Fortunately, no toxins were found in the samples they tested. "This made us happy, because there are reports in the literature about other species of Gliotrichia that produce toxins from the microcystin group, which can damage the liver," explains Zahari. "Our next step is to check whether genes for toxin production are present in Galiotrichia from the Sea of Galilee. That is, does the potential for the production of toxins even exist and it may manifest itself under certain conditions." According to Zahari, Dr. Ruthi Kaplan-Levi's preliminary findings indicate that the answer is no, but she will continue to investigate until receiving a final and absolute answer.
Pom-pom from blueberry bushes
Not only the negative effect of the gliotrichia interested the researchers, but also their positive effect. They checked the nutritional value of the gliotrichia and its effect on the ecosystem (for example, is it food for fish?)
Another issue that required a more careful examination was the fact that when the gliotrachia grows on the existing reed it does not allow other species to develop on it alongside it. Therefore, it was decided to check with molecular methods what the structure of the gliotrichia is and what tiny microorganisms live in the environment of the species.
In a microscopic examination, the researchers discovered that the colony structure of the algae is pompon-like on the outside, made of threads that all converge to one central point while the other end is free. The hairs of the pompon form a kind of thick forest, which is full of hiding places and food for different bacteria and microorganisms (algae species, bacteria and fungi).
"We saw that the Hagliotrichia colony constitutes a kind of small-scale ecosystem and a complex habitat for a large number of species," explains Zahari. Indeed, molecular tests performed by Dr. Naama Lang-Yona in the laboratory revealed that the Gliotrichia colonies are inhabited by dozens of species of additional microorganisms.
Until all this new information is collected and analyzed, it seems that the mystery of the origin of the arrival of the new species in the Sea of Galilee - whether it is an invader or not and what are its characteristics - still remains. The researchers are left with many questions that require further research, but nevertheless they speculate that this is an invasive species that has not been mentioned before in any source in Israel. "It may also be a rare eruptive species that has not been documented and has become very common recently due to a change in environmental conditions," adds Zahari. "In any case, we assume that the Gliotarchia will remain in the Sea of Galilee in the future and hope that it is not a toxic invasive species."
עAnd on the topic on the science website:
