January 12, 2023 - How does the cell build a supporting structure for chromosomes? For years, scientists have been trying to understand how spindle fibers form, which are cellular structures crucial for the proper distribution of chromosomes. A new paper by Croatian researchers from the Ruder Boskovic Institute published in the prestigious journal Nature Communications sheds light on this issue.

Researchers from the team of prof. Dr. Sc. Iva Tolić from the Ruder Boskovic Institute (IRB), in collaboration with colleagues from the Faculty of Science, University of Zagreb (PMF), and Croatian scientists in the diaspora, described how the cooperation of kinetochores and microtubules is crucial in the assembly of the spindle fibers and in determining the movement of chromosomes during cell division, as reported on the Ruder Boskovic Institute's official website.

The scientists reached these results by applying their knowledge of cell biology and theoretical physics and thanks to new approaches and methods of cell microscopy that they developed for this research, which enabled them to study hitherto unseen structures of the spindle fibers in the earliest stages of cell division.

The results, published by this interdisciplinary research team are extremely valuable because they contribute to understanding cell division and the diseases associated with this important process.

Iva Tolić, Marin Barišić and Nenad Pavin - Ruder Boskovic Institute

How are chromosomes organised during cell division?

Our bodies are made up of about one hundred trillion individual cells created by division from a single cell. Spindle fibers, dynamic micromachines composed of protein tubes - microtubules, are responsible for that division. Although the assembly of the spindle fiber is essential for proper chromosome division, this process has not been fully elucidated due to its complexity.

The spindle fiber has a unique architecture consisting of evenly distributed bundles of microtubules - kinetochore bundles, which are attached to chromosomes, and bridging bundles composed of microtubules, which connect the two poles of the spindle fiber by folding in the middle.

While the formation of kinetochore fibers has long been investigated in many laboratories around the world, how the bridging bundles are assembled has remained unknown. Without these bridging bundles, spindle fibers end in a star shape that cannot separate chromosomes. This is proof that bridging bundles play an indispensable role in cell division.

To clarify the formation of bridging bundles of microtubules, group of Professor Iva Tolić teamed up with the group of Professor Marin Barišić from the Danish Cancer Research Center in Copenhagen and the group of Professor Nenad Pavina from PMF Zagreb as part of the project of the Croatian Science Foundation (HrZZ) under the programme encouraging cooperation with Croatian scientists in the diaspora.

The project was completed with the publication of the results of interdisciplinary research in which, combining cell biology and theoretical physics, the researchers discovered the phase transition of microtubules from a sparse network structure to dense, well-separated, and properly organised bundles of the spindle fibers.

Experiments conducted by student Jurica Matković showed that this transition occurs because motor proteins on kinetochores, which are located in the central part of each chromosome, bind to microtubules.

Binding requires the activation of motor proteins by Aurora kinase B, a protein that has multiple roles during cell division. This result was proven by experiments based on motor protein mutants by researchers led by Prof. dr. sc. Marin Barišić.

When motor proteins bind to microtubules, cross-linking proteins cross-link the microtubules into a bundle attached to the kinetochore. The mutual repulsion of the condensed chromosomes, which push against each other on the equatorial plane of the spindle fibers and thus lead to the separation of the bundles to which they are attached and the expansion of the structure into a characteristic spindle shape, is responsible for not all microtubules joining into a single bundle. This novel mechanism of bundle formation is relevant not only to microtubule-based structures but also to cytoskeletal self-organisation in general.

Young researchers have developed new approaches and methods in cell microscopy

"To be able to reveal these complex processes, our research team devised new approaches and developed better methods for observing the spindle fibers. Rapid imaging of microtubules in the cross-section of the spindle fibers allowed us to monitor the dynamics of microtubule redistribution in a living cell. Until now, it was impossible to achieve this with conventional approaches due to the large number of microtubules and the high speed with which they are reorganised. With the help of super-resolution STED microscopy, young researchers were able to analyse the previously unseen architecture of microtubules in the earliest stages of cell division,'' explains Professor Iva Tolić, head of research at IRB.

Super-resolution microscopy protocols were developed on a microscope purchased as part of a project financed from the European Regional Development Fund as part of the Operational Programme Competitiveness and Cohesion 2014-2020.

Jurica Matković, Mateja Ćosić and Subhadip Ghosh - Ruder Boskovic Institute

The group of Professor Nenad Pavina studied the physics of the formation of microtubule bundles from PMF, where postdoctoral student Subhadip Ghosh developed a theoretical model that allows for identifying the conditions necessary for the formation of the bundles. Since this is a complex process, a minimal model is helpful in understanding the interplay between microtubules, kinetochores, chromosomes, and crosslinker proteins and their roles in bundle formation. The model results support the central hypothesis that the attractive and repulsive mechanisms revealed in the experiments drive the formation of microtubule bundles.

The functional importance of this concept is evident in the context of proper chromosome division, given that PhD student Mateja Ćosić showed in this paper that improper formation of bundles leads to errors in chromosome division due to failure to correct improper connections between microtubules and kinetochore.

The authors propose the intriguing hypothesis that Aurora kinase B not only promotes the formation of overlapping bundles by activating motor proteins, but uses these same bundles as pathways to kinetochores to correct misconnections there.

Irregular and overly thin bundles lead to lagging of individual chromosomes, due to which one daughter cell may receive too many chromosomes, and the other too few.

"The wrong number of chromosomes is characteristic of tumor cells and is associated with the formation of metastases. That's why errors during chromosome division are intensively investigated in laboratories around the world, and this work adds a piece to the puzzle of understanding cell division and diseases associated with this important process,'' the scientists concluded.

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ZAGREB, 8 July 2022 - On the occasion of National Nikola Tesla Day - the day of science, technology and innovation, observed on 10 July, President Zoran Milanović received scientists from the Ruđer Bošković Institute on Friday, who presented the results of research on the impact of microplastics in aquatic ecosystems.

Researchers from the Ruđer Bošković Institute (RBI), the Institute of Pharmaceutical Sciences of the University of Graz and a PhD student from the Institute of Physics in Zagreb presented their innovative research, the President's Office said in a press release.

The results obtained by studying the interactions of microplastic particles with calcium carbonate indicate that the exposure of microplastics to dissolved organic matter present in aquatic ecosystems enhances the incorporation of such modified microplastics into calcium carbonate, which is the main inorganic component of shells, corals and other aquatic organisms.

The Ruđer Bošković Institute researchers underscored that the longer plastic is present in water systems, the more dangerous it becomes, and from the primary form of plastic such as bags or plastic bottles, it is degraded by actions in nature into secondary microplastics, smaller particles that enter organisms.

The research, they said, was done as part of the project "Can we clean the oceans and seas from microplastic by using calcium carbonate encapsulation."

It was funded by the European Institute for Innovation and Technology, EIT Klima - KIC Alumni Program "Participatory Grantmaking" and a project by the Croatian Science Foundation.

The findings of the research were published, as stated, in the prestigious scientific journal Environmental Chemistry Letters.

ZAGREB, 11 Feb 2022 - On the occasion of International Day of Women and Girls in Science, observed on 11 February, the Zagreb-based Ruđer Bošković Institute (RBI) issued a statement on Friday regarding the importance of raising awareness of gender equality in science, technology, engineering and mathematics (STEM).

In order to achieve full and equal access to and participation in science for women and girls, and further achieve gender equality and the empowerment of women and girls, in 2015 the UN General Assembly adopted a resolution declaring 11 February as the International Day of Women and Girls in Science.

Three in five scientists and researchers in the institute are women

The RBI says the institute employs as many as 793 scientists and researchers and 61% of them are women. This share of female researchers is above the Croatian and European average.

According to data collected by the European Union's statistical office (EUROSTAT) in 2020,  women made up 51% of the total number of employees in science and technology in the EU, while in Croatia this share stood at 55%.

Concerning doctoral degrees in natural sciences, in Croatia, there were more women than men with PHDs (55.5%) in 2020, and in the institute as many as 60% of holders of PHDs in Science were women.

On 8 February 2022, there were 1,010 people on the RBI payroll and 603 of them were women.

Also of the three assistant directors of the institute, two are women.

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October 1, 2021 - In cooperation with their colleagues from Germany, the Croatian Scientists' tissue research brought about some new findings that made the news in the international scientific community.

Dr. Ana Sunčana Smith from the Ruđer Bošković Science Institute (IRB) is one more IRB scientist to find herself leading an international scientific team towards new exciting discoveries. Made up of IRB Croatian scientists and Germany's Friedrich-Alexander University from Erlangen-Nürnberg, Sunčana Smith's team (the members being Sara Kaliman, Maxime Hubert, Carina Wollnik, Lovro Nuić, Damir Vurnek, Simone Gehrer, Jakov Lovrić, Diana Dudziak, and Florian Rehfeldt) came to a new understanding on the mechanical properties that affect Epithelial Tissue (the form which covers all human bodies).

Their scientific paper titled ''Mechanical Regulation of Epithelial Tissue Homeostasis'' has recently been published in the prestigious Physical Review X scientific journal for the study of physics.

As IRB explained in their press release, diseases or injuries to the organism change the elasticity of microcellular surroundings during our lifetime.

''Despite recent efforts to understand homeostasis in epithelial tissues, there are many unknowns surrounding this steady state. It is considered to be regulated by mechanoresponse, but unlike for single cells, this idea remains heavily debated for tissues (…) Our results unequivocally relate the mechanosensitive properties of individual cells to the evolving macroscopic structures, an effect that could be important for understanding the emergent pathologies of living tissues,'' reads the abstract of the paper.

While the current researchers focused on a single cell, IRB points out that tissue research like this is scarce.

"This result showed us a more complicated connection between density and cell movability than has been known before. We determined that the organisation of the epithelial tissue is very robust despite great variations in density lead by the various hardness of micro-surrounding. This shows that density is the result of adaptation and that the cell organisation is actively controlled to fulfill its function. This fact can be used in diagnostics, and it has potential implications in understanding the process of epithelial regeneration,'' concluded Dr. Ana Sunčana Smith.

This is just one of the great results discovered by IRB, the biggest scientific institute in Croatia. As previously reported, this includes spindle and cell division research, quantum communication development (presented at the G20 Summit), heavy metal analysis in the Adriatic Sea, and much more.

Learn more about Croatian inventions & discoveries: from Tesla to Rimac on our TC page.

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September 14, 2021 - The first Croatian STED microscope purchased and owned by the Ruđer Bošković Institute (IRB) in Zagreb offers new opportunities for Croatian scientists and researchers.

The super-resolution microscope (STED) worth 4.5 million kuna has become a new edition to the selection of delicate but useful equipment the Ruđer Bošković Institute (IRB) uses to tackle the hottest questions faced by modern science.

As IRB reported in its press release, the microscope made its way to Iva Tolić's lab with thanks to the European Union funds.

"Stimulated Emission Depletion microscopy (STED) is a super-resolution technic of fluorescent microscopy and one of the methods of overcoming the limitations of visible light microscopes in observing matter structures of incredibly small sizes. German physicist Stefan W Hell received the Nobel Prize for developing STED in 2014,'' informed IRB in its press release. It also stated this is the first microscope of its kind in all of Croatia.

''With the help of this STED microscope, we can see three times the amount of small structures in a cell than we could before with the standard microscopes. We'll use them for observing cell division, more precisely for chromosome division. When it comes to division, it's very important that the chromosomes are well-connected microtubules, which are protein pipes that tie chromosomes and pull them onto separate parts of the cell. With this type of microscopy, we'll be able to determine how microtubules are connected to chromosomes in various phases of spindle formation, which is still a mystery,'' explains Iva Tolić.

As TCN previously reported, Iva Tolić's team already made a significant contribution to cell biology and spindle research when their work led them to new information on microtubule-sliding.

In addition, back in 2014, the then-president of Croatia Ivo Josipović awarded her the Order of the Croatian Danica (the medal which boasts an image of a famous scientist, Ruđer Bošković) for her particular contribution to the promotion of science in Croatia and abroad.

''Tolić earned her international reputation due to her research into complex cellular processes. Namely, not so long ago, in cooperation with her colleagues from the Max Planck Institute, Tolić discovered the first potentially immortal organism – a special kind of yeast, which was isolated from African beer. This type of yeast is very special because it rejuvenates every time it reproduces. In the case of most other yeasts, the mother cell creates a young daughter cell while it ages and eventually dies. Contrary to that, the mother cell of this yeast splits into two equal daughter cells, which remain young throughout their divisions,'' wrote IRB on its website at the time of the ceremony.

With Tolić's international reputation and well-established name, as well as scientific findings found by other scientists at IRB, it is understandable that European Union funds supported the further development of IRB's equipment.

''The outstanding power of STED microscopy allows researchers to discover complicated processes in cell structures. These understandings are the basis for further research on how specific medications, chemical compounds or bacteria and viruses affect processes in a live cell,'' concluded IRB's press release.

Learn more about Croatian inventions and discoveries from Tesla to Rimac on our dedicated TC page.

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September 10, 2021 -The Ruđer Bošković Institute plasmonic effect research described the property of nanoisland metal films of silver and copper which can be seen in various applications, particularly in green technology development.

Metal nanoparticles are submicron scale entities made of pure metals (e.g., gold, platinum, silver, titanium, zinc, cerium, iron, and thallium) or their compounds (e.g., oxides, hydroxides, sulfides, phosphates, fluorides, and chlorides), as explained by the Science Direct website.

When it comes to modern science, a particular interest in metals has now shifted to the Plasmonic effect. This effect is an interaction between free electrons in metal nanoparticles and incident light, as briefly explained by the National Institute of Technology Calicut physics department researcher Shamjid Palappra.

With this question raising curiosity among scientists worldwide, it was impossible for the Ruđer Bošković Institute (IRB) in Zagreb and their optics laboratory to not dive into the subject themselves.

As IRB reported, Matej Bubaš, Vesna Janicki, Stefano A. Mezzasalma, Maria Chiara Spadaro, Jordi Arbiol, and Jordi Sancho-Parramon authored a research titled ''Tailoring plasmonic resonances in Cu-Ag metal islands films'' which was then published in a respected Applied Surface Science journal.

IRB's optics lab collaborated on this research with colleagues from the Lund Institute of Advanced Neutron and X-ray Science (LINXS) in Sweden, and two institutions from Catalonia in Spain, the Catalan Institute of Nanoscience and Nanotechnology and ICREA.

''The plasmonic response of Cu-Ag metal islands films is being investigated. Films are obtained by the subsequent electron beam deposition of Ag and Cu using different fabrication conditions: the deposited mass thickness, then comes the substrate temperature, and then the post-deposition annealing in the vacuum. The optical properties of the films are investigated by spectroscopic ellipsometry and then correlated with the structural characterisation results obtained by electron microscopy,'' explained the abstract of the research concerning the metal island combination of silver (Ag) and copper (Cu).

''Overall, it has been shown that Cu-Ag island films are compelling systems for plasmonic applications, as their optical response can be widely and easily tuned by adjusting the fabrication conditions,'' the abstract summarised.

IRB's press release clarified the research goals, stating that the scientists described how plasmonic properties could be adjusted for the preferred types of radiation, be it infrared, visible light, or ultraviolet radiation. These descriptions and setup possibilities of nanoisland plasmonic properties bring with them a plethora of applications.

''Devices that use plasmonic effects already upgraded their diagnostics and spectroscopy, while research in the direction of upgrading the conversion of solar energy and manufacturing catalysts that would turn toxic compounds into useful ones carry great potential for the development of new green technologies,'' pointed out IRB's press release.

Developing green technologies and turning toxic compounds into useful ones is not a new thing for IRB, as TCN previously reported.

Learn more about Croatian inventions and discoveries from Tesla to Rimac on our dedicated TC page.

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September 9, 2021 - The Višnjan Observatory and other relevant institutions are enrolled in the Scope Project. Under the motto "Science connects people", the goal is to popularise and improve the STEM area in Croatia.

When it comes to astronomy in Croatia, the Višnjan Observatory in Istria holds the top place as the best location to gaze up at the stars, and both the Croatian and international public seems to recognise that.

The work undertaken there speaks for itself, especially when it comes to events like discovering new asteroids, and people's willingness to support the cause is evident in a successful crowdfunding campaign earlier this year.

Since the end of October 2020, the observatory has been enrolled in the Scope Project, which under the motto of ''Science connects people'', aims to promote the STEM area.

''The goal of the project is to create a network of cooperation for all relevant actors in the goal of making encouraging the creation of an environment for the development and progress of the STEM area in the sense of strengthening capacities and cooperation of the civil society organisations, as well as common cooperation in shaping STEM area public policies,'' says the Višnjan Observatory's website.

Others the Višnjan Observatory cooperates in this project with include the Ruđer Bošković Institute (IRB), several faculties from Zagreb University (Faculty of Mechanical Engineering and Naval Architecture, Faculty of Architecture), the Carpe Diem Association for the creative and social development of kids and adults, the Croatian Interdisciplinary Society and many more. The project will last until October 28, 2023, on a budget of 3,599,107 kuna.

''The latest data clearly showcases the lack of students and experts in the STEM area. The need for activities in the STEM area is recognised in the National Strategy of education, science, and technology,'' says the Višnjan Observatory website, highlighting the need for this project.

With the already mentioned networking and collaboration in making policies, the plan of the Scope Project is to also survey public opinion, which will provide data for the higher scientific institutions to conduct research and to guide propositions for public policies.

Despite Croatia lacking experts and general interest in the STEM area, it is comforting to know that those interested in the area are indeed quite successful. Croatian scientists represented Croatia during the G20 summit as they participated in the first quantum communication, students achieved fantastic results during the informatics competition, and IRB scientists frequently make international scientific news with the dedicated work of their scientists (just to mention few examples).

Learn more about Croatian inventions and discoveries from Tesla to Rimac on our dedicated TC page.

For more about science in Croatia, follow TCN's dedicated page.

September 1, 2021 - New research led by the scientists from Ruđer Bošković Institute (IRB) concerns Adriatic heavy metals. The current concentrations are small but worth monitoring. Learn more here.

With scientists from the prestigious Ruđer Bošković Institute (IRB) already publishing their results from measuring the salinity of the Adriatic, the new endeavors show that salt isn't the only thing worth exploring in Croatia's geographical and tourist ace.

IRB scientists Abra Penezić, Andrea Milinković, Saranda Bakija Alempijević, and Sanja Frka, alongside their colleague Silva Žužul from the Institute for Medical Research and Occupational Health in Zagreb, authored a scientific article ''Atmospheric deposition of biologically relevant trace metals in the eastern Adriatic coastal area'' and published it in the renowned multidisciplinary journal - Chemosphere.

The research was focused on sedimentation traces of atmospheric metals on the surface of the Adriatic sea. The metals that were traced in this research were zinc, copper, lead, cobalt, nickel, and cadmium. With all of them being heavy metals (not in a fun, artistic way like Metallica or Iron Maiden) that pose a serious threat to human health, keeping a close eye on their levels in the Adriatic is a more than important task.

''Atmospheric transmission isn't just significant, it's often the dominant way in which natural and anthropogenic (man-made) transfers occur from land to the marine area. Once injected through processes of dry or wet sedimentation, atmospheric flying particles or aerosols become the outside source of nutritious but also toxic matter for marine ecosystems. Atmospheric sedimentation can be of significant value for waters that are poor in terms of nutritious salts, such as the area of central Adriatic,'' informed IRB in its press release.

They added that the coastal area of the Adriatic sea is under the constant influence of man-made aerosols of the urban and industrial areas of continental Europe. In addition, spring and summer see the influx of Sahara dust, and with the coastal area being a high-risk area of open fires, aerosol contribution increases. However, IRB states that the effect of fire aerosols on surface maritime systems still isn't being properly researched to this day.

''In this research, we looked at the variability of the concentration of biologically significant metals in traces and their sedimentation on the surface waters of the central Adriatic. At the Martinka sea station, we did a six-month-long sampling of PM10 particles, total sedimentation matter, seawater from a depth of one metre and the surface microlayer as the border between the sea and the atmosphere,'' explained the leading author, Dr. Abra Penezić.

PM10 is a problematic particle as it remains for a very long time in the atmosphere due to its small size and ability to remain there, warns the Belgian Interregional Environment Agency.

Dr. Abra Penezić © Ruđer Bošković Institute

The research showed that in colder periods of the year, the increase of metal traces of zinc, cadmium, and lead in the Adriatic is owed to the heating systems and transportation from continental Europe.

In the summer, increased traffic emissions allow nickel, cobalt, and copper to be on the rise. The rain increases wet sedimentation and, along with open forest fires and Sahara dust, they become factors of increasing metal particles. The IRB press release states that while the concentration of this article is small, it is important to constantly monitor these levels.

''The results of this research will contribute to the further knowledge on processes on this specific area and the dynamics of the atmosphere and the sea,'' they explained from IRB.

This research is also part of the BiREADI research project. It began back in 2018 and will last until 2022 with a million kuna budget, the project aims to explore the complex dynamic and mutual influence of the atmosphere and the sea, an important and profound question to answer in respect both to the climate challenges we experience now and those that are yet to come.

Learn more about beaches in Croatia on our TC page.

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August 6, 2021 - What the country lacks in terms of economy, it makes up for in science. This was proven during the Croatia on G20 Summit. Along with their counterparts from Slovenia and Italy, Croatia's Ruđer Bošković Institute (IRB) scientists conducted the first quantum communication, presenting new and safe communication technology.

Unfortunately for the Croatian economy, the country is far from being a member of G20, let alone the prestigious G7, but with the European Union being a member of G20, it's a bit like Croatia is also on the team, too.

Croatian businesses may still face issues, but Croatian science saves the nation's reputation, particularly the Ruđer Bošković Institute (IRB). As they reported in their press release, Croatia participated in the first public demonstration of quantum communication, along with Italy and Slovenia on the fifth of August. This transmission took place between Trieste, Ljubljana and the Croatian city of Rijeka, and thanks to their scientific expertise, attention was given to Croatia during the summit of the wealthiest countries on the planet.

Dr. Mario Stipčević (head of the IRB's photonics and quantum optics laboratory) and Dr. Martin Lončarić from the IRB handled the transmission from the Croatian side with the support of his colleagues from the Faculty of Transport and Traffic Sciences from Zagreb University and in collaboration with the OIV company which is enrolled in digital signals and networks.

''The quantum connection between Trieste (Italy) and Croatia's Rijeka-Zagreb knot is 100.5 kilometres long and is expanded from Rijeka to the capital of Zagreb via quantum induced communication. The first demonstration of its kind has been made possible with the cooperation of the Croatian academic community and industry,'' said Dr. Stipčević.

According to the website of PicoQuant, a German company dedicated to research and product development, quantum communication is a field of applied quantum physics closely related to quantum information processing and quantum teleportation.

''Its most interesting application is protecting information channels against eavesdropping by means of quantum cryptography,'' says PicoQuant.

The IRB explains that quantum communication satisfies the need for safe communication, which is a priority of every government worldwide.

''This technology achieves maximum security thanks to the quantum encryption that works on the photon exchange, which allows for the instant detection of hacking attempts,'' they pointed out from the IRB.

''Today, we're part of the cornerstone of the new European quantum infrastructure“, said Tommaso Calarco, the president of the European Quantum Community Network (QCN). He added this is the crown of the first phase of the Quantum Flagship programme which offers European Union citizens such privacy protection infrastructure.

Croatia, by all accounts being involved in the shaping of The European Quantum Communication Infrastructure (EuroQCI) Initiative, shows the country will not lack behind its other European partners.

''With the success in realising this demonstration, our scientists and experts broke the ice and paved the way to the realisation of quantum infrastructure in the Republic of Croatia,'' concluded Dr. Stipčević.

Learn more about Croatian inventions and discoveries from Tesla to Rimac on our dedicated TC page.

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Aug 5, 2021 -The salty Adriatic Sea became saltier in 2017, and even in 2021, the salinity levels are the highest ever recorded, warns the Ruđer Bošković Institute (IRB).

With known salty areas such as Pag, you would expect the Adriatic sea to be very salty, and it is. However, over the years, it has become even saltier, as the Ruđer Bošković Institute (IRB) stated.

As the IRB wrote in a press release, a Croatian scientific team collaborating with their Italian colleagues published a study that shows so far unrecorded levels of salinity in the Adriatic. Their work was published in the prestigious Frontiers in Marine Science Magazine titled ''Observation, Preconditioning, and Recurrence of Exceptionally High Salinities in the Adriatic Sea“.

As the IRB explained, it was in 2017 around Palagruža where the Adriatic sea's salinity reached a record of 39.1 per mille.

''In addition, with minor oscillations, the high salinity in the first 200 metres of depth was kept within the central part of the southern Adriatic, and it has remained the case until today. For example, at this moment, the salinity levels in the central part of the southern Adriatic is over 38.8 per mille in the whole water gauge, and 39.15 per mille by the surface,'' added the IRB.

This measurement was the lead for the scientists to conduct further research that incorporated various available data acquired via multiparameter probes, autonomous ARGO buoys, remote-controlled submarines, and satellites that measure sea level's surface. The data from an oceanographic model of the Mediterranean sea (which combines satellite and other measures, thus giving the most quality 3D view of the oceanographic field) was also used.

Sure enough, the salinity rise has been explained. On one hand, the enhanced flow from the Middle East and the Ionian sea are to blame, but on the other, there are changes in the Adriatic sea itself.

''The processes (in the Adriatic sea) occur on a scale of several days to a decade, and have four key elements,'' they explained from IRB.

The first one concerns Adriatic-Ionian bi-modal oscillation affecting physical and biogeochemical conditions in the Adriatic through a period of 5-10 years, which, in the last decade, has caused a serious influx of salt and oligotrophic waters (waters which are too low in nutrients to support life).

The second process concerns low river flows due to the low amount of rainfall, while the third process concerns the enhanced amount of solar energy on the sea's surface during summer and early autumn. Finally, with the weather warmer than average and with very little wind, the water gauge is divided into the hotter surface level and colder central and bottom levels. This leads to the fourth process that includes vaporising and the loss of water from the sea surface.

''Three out of four of the aforementioned processes have already been documented in the Mediterranean as a consequence of climate change that in the future will bring warmer, drier summers and as a consequence, more heat and the higher salinity of the sea surface,'' they warned from IRB. They added that this is a threat to marine life which depends on the temperature, the level of salinity, and other factors that will be sabotaged with these changes.

With the Adriatic sea and its marine life being one of the treasures Croatia has, the global response to climate change must start giving results as fast as possible, and Croatia cannot afford to miss out on contributing for the sake of the country and the world in general.

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