EGU Blogs


Conversations on a century of geoscience in Europe: Günter Blöschl

Over the last century, geoscientists have made incredible contributions to our understanding of the Earth, the solar system, and beyond. Inspired by the American Geophysical Union (AGU) and the International Union of Geodesy and Geophysics (IUGG) centennials, which are celebrated in 2019, we would like to highlight Europe’s role in shaping the geosciences and the great achievements of European geoscientists within the last century.

In this series of interviews, scientists reflect on the last 100 years of Earth, space and planetary sciences in Europe and share their perspectives on the future. 

Günter Blöschl: Head of the Institute of Hydraulic Engineering and Water Resources Management and Director of the Centre for Water Resource Systems of the Vienna University of Technology

In your opinion, what are some of the biggest ways Europe and European scientists have shaped the geosciences within the last century? 

Europe and European scientists have, according to my view, shaped the geosciences along three dimensions: technologies, ideas and societal needs (see this paper on the factors that have shaped the growth of hydrological understanding in the last century). New technologies, such as satellite data have immensely advanced essentially all the geosciences, together with new ideas, and all this hinges on the value society gives these developments through funding opportunities. From my vantage point as a hydrologist, I view the progress in scientific understanding sandwiched between two main external drivers:

  1. Changing societal needs, such as flood design, land management, and improving water quality — hydrological understanding cannot be less than what society really needs;
  2. Changing technological opportunities, such as instrumentation technology and computing power that come from advances made in other fields — hydrological understanding cannot be more than what technology allows.

New ideas were generated by hydrologists addressing societal needs with the technologies of their time. The growth of ideas in other geosciences was probably similar although, in some of them, societal needs may have played a lesser role.

Which European researcher from the last century has influenced your work the most?  

In the geosciences, I admire the work of German geophysicist Alfred Wegener. By analysing global spatial patterns, Wegener found similarities in rock type, geological structures, and fossils in far away continents, indicating to him that these continents must at one time have been together, thus laying the foundations for his theory of continental drift. At the time, his theory was highly controversial; for example, in 1926 it was referred to by geophysicist William Morris Davis from Havard University as “the Wegener outrage of wandering continents” in an article published in Science (Davis, 1926, p. 464). Wegener had the right idea with which to see order in the apparent disorder and, even more importantly, he was a great synthesizer.

More specifically in my field, the work of Irish hydrologist Jim Dooge has influenced me a lot. He, too, was a great synthesiser. He advanced a scale perspective of hydrological processes – how small scale processes aggregate to larger scale processes, thus linking subsurface and surface hydrology and he linked a variety of different methods for modelling how much water runs off the landscape into the rivers. At the same time he linked these theoretical considerations with practical concepts that can actually be used in the engineering practice. I believe he has been a hero for many of us in hydrology. It is not a coincidence that he is the first recipient of the EGU John Dalton medal.

For the next generation of researchers, what skills/technology/concepts do you think will be the most important for advancing the next century of geoscience? 

The most thrilling research questions are getting more interdisciplinary. For example, the critical water problems we face in the 21st century are complex, involving feedbacks across multiple scales, sectors and agents. Addressing these problems requires radically new ways of thinking. The important feature is the focus on co-evolution and emergent patterns.

For example, how are the vegetation dynamics over decades linked to individual flood events, and vice versa; or how does small scale land degradation affect droughts at much larger scales? How are soil, vegetation, climate and hydrological processes linked in the Earth System? This linkage is not only important for the entire Earth as a system, but also for much smaller units such as hillslopes and catchments.

This more holistic view requires synthesisers. Synthesisers in the spirit of Alfred Wegener and Jim Dooge. Synthesisers that are firmly grounded in their parent discipline and reach out to the related disciplines in a way that goes beyond coupling computer models and involves holistic conceptual thinking.

What do you think will be the biggest challenges for the geosciences in the next century? 

Where are the geosciences going in a world where about every aspect of life is changing more rapidly than ever? Clearly, it will not suffice to respond to any changes, but we need to play an active role in shaping a well-connected community of Earth scientists, shaping a climate where the geosciences can thrive, and helping shape a society where our research findings make a real world impact.

Key elements of realising this pro-active role will be cooperation between disciplines, and a permanent insistence on scientific innovation. As a learned society, EGU has a strong track record in innovations in communication, such as being a trend setter in Open Access publishing and interactive presentations (PICO). I am sure that EGU will continue to play a leading role in this exciting process.

My second observation regarding change refers to the Earth system itself.  We are living in the “Anthropocene”, the era where the human footprint is omnipresent, so treating humans as mere boundary conditions, as we are usually doing now, may no longer be adequate. It no longer suffices to look at the effects of the water cycle on humans (as we do when analysing flood damage) or the effects of humans on the water cycle (as we do when analysing water pollution) in isolation. What is needed is a coupled approach that accounts for the two-way interactions of humans and water over time scales reaching from seconds to decades.

Other areas of the geosciences may face similar challenges. We need to work in an interdisciplinary way to understand long term interplay of humans and geoprocesses which are needed to address a plethora of both local and global issues, and advance the geosciences. As Heraclitus said, there is nothing permanent except change. Innovation needs to be permanent. We are in for an exciting future.


Davis, W.M., 1926. The value of outrageous geological hypotheses. Science, 63 (1636), 463–468. Available from:

Sivapalan, M. and Blöschl, G., 2017. The growth of hydrological understanding: technologies, ideas, and societal needs shape the field. Water Resources Research, 53, 8137–8146. doi:10.1002/2017WR021396

Emerging Contaminants: The Rough Teenagers

Emerging Contaminants: The Rough Teenagers

In geochemistry I see the term “bad actors” used more often than it should be to describe well-known environmental contaminants. “Bad actors” refers to contaminants we see frequently in the environment and know have significant environmental or human health effects. Think mercury, nitrates, lead, arsenic, sulphur dioxide, etc.

However, this article is on the up and coming contaminants that are just starting to achieve awareness in the environmental community so I thought calling them rough teenagers was an apt play on words. Feel free to call me out for my use of rampant hyperbole. Nonetheless, the contaminants/classes of contaminant described here are starting to cause major environmental problems and accompanying angst for environmental scientists, regulators and companies. They are certainly starting to appear more frequently in the scientific literature as the academic community is alerted to their presence and potential effects, which results in an increase in publications exploring their environmental behaviour and impacts.


Pharmaceuticals are a major emerging contaminant. It seems like hardly a day goes by without another article on pharmaceutical products in major water bodies or how they pass through water treatment plants. The way a pharmaceutical product ends up in the environment is simple. We take them, pee out the excess which ends up in the water treatment plant or septic system and then is released to the environment. These drugs still retain their efficacy, at least to some degree, when they enter the environment and therefore can induce huge impacts throughout the ecosystem as they act on organisms much smaller and much different to humans.

Microbeads and Personal Care Products

This is a trendy one. Microbeads and similar additives to cosmetics and shampoos have really caught the attention of the media and their environmental impacts have not yet been fully understood. Microbeads are tiny, tiny pieces of recycled plastic, usually polyethylene or similar petrochemical plastics, that are added to personal care products to give them an abrasive feel when used. They make your shampoo feel like it’s rubbing/cleaning your scalp or skin. However, their environmental impact when you wash your shampoo down the drain is where the problem with microbeads starts. Their small size, less than 5mm and commonly much smaller than that, means they can pass through water treatment systems and enter freshwater bodies and the ocean. Once circulated within these waterbodies they are ingested by fish, birds and other aquatic life posing a threat to their health. In fact, the threat of microbeads and the fact that their concentration has increased in large water bodies so rapidly has led to their ban in many nations. Hopefully, we’ll be able to take microbeads off this list soon!

A sample of microbeads collected from Lake Erie. (Source)


When you hear about element 34, Se, you might think of it as a helpful micronutrient, dandruff killer or it’s namesake, Selene, the Greek word for the moon. Unfortunately, it is much more harmful to the environment than we previously realized. The toxicity of selenium relates to the fact that it is a teratogen for fish and is even toxic for humans at higher doses. This means, that it leads to birth defects in fish and can lead to the disease selenosis in humans. The concentration at which it induces birth defects is also much lower than previously realized. Compounding selenium’s high toxicity is the fact that it is quite mobile in the environment and is easily transported in groundwater and surface water making it very difficult to control. Selenium is often released to the environment from mines as it co-occurs with a wide variety of other elements, such as lead, nickel, uranium, gold, and coal.


I see articles on this come up all the time, particularly about silver and copper nanoparticles, but there are others as well. It seems that the research community is kind of playing catch up in terms of assessing the transport and effect of nanoparticles on the environment, but I’ve started to see lots of articles on them now. Nanomaterials are particles that have a size range of 1-100 nanometres (10^-9 to 10^-7 m). They are used for an ever expanding variety of applications at the moment including coatings to add strength, keep your smelly socks from smelling, in electronics, in medecine, etc. The list is huge. However, once these nanomaterials have served their purpose or during their use they can be released to the environment. Once in the environment at higher concentrations these nanoparticles, often made of silver, carbon, titanium, cerium and other metals, can be ingested and inhaled by people and animals or enter the aquatic environment and expose fish and other aquatic biota. The effects that they have vary widely and are just starting to be understood but some types, such as silver, may affect plankton and algae, the basis upon which the aquatic food chain is built.

The COLT. A hockey stick that has a Ni, Co nanomaterial coating that is supposed to make it more resistant to breaking. Sadly, mine broke after many hard games, but not enough goals.

Rare Earth Elements

Rare earth elements (REE’s) such as cerium, dysprosium, lanthanum, etc. are being mined in greater quantities than even before to enable the production of cell phones and computers. Their widespread use has led to a boom in rare-earth element exploration and mining around the world as well as their relatively recent appearance in the litany of environmental contaminants. As newcomers, their effects are not yet fully understood, although given the increase in mining, research on the environmental effects of REE mines is forging ahead (I’m not sorry about the pun). Environmental exposure to REE’s has been implicated in a wide variety of human and ecological health effects  such as cardic and respiratory issues. The mining of REE’s can also release a wide variety of other toxic elements such as arsenic, lead and cadmium. Furthermore, REE ores are often also enriched in radioactive elements, such as uranium and thorium, which can make REE mine wastes a radiological concern. If care is taken during the mining stage, however, REE’s can be mined safely.

One of the booming uses of REE’s is in electronics

These are just a few of the emerging contaminants I have seen gaining traction flipping through the literature. There are loads more unfortunately. As we develop new and better technologies the unintended consequence is that the waste products or products themselves may pose an environmental threat that we do not predict or understand in order to bring the product to market. It usually falls to the scientific community and regulators to bring awareness of the effects these contaminants have and propose solutions. Every action has a reaction, and the development of new industries and new technologies often results in environmental effects that can take many years to discover and resolve. That said, by being aware of these emerging threats to the environment it is possible to take steps to reduce their harm before it is too late. The very brief overviews above do not do justice to each category and the complexity of their environmental transport and effects; particularly as studies in the natural environment are uncommon and most toxicity information is based on lab tests.

There are a lot of other new and not so new contaminants that are still cycling through the environment. There are also some success stories where problems were recognized and fixed so I don’t mean to imply that all hope is lost. If you can think of some additional “rough teenagers” that I did not bring awareness to here please post them in the comments section!


Photo of the Week

Photo of the Week

Keepin’ then comin’! This weeks photo is brought to you by Immageo as per usual. It can be found: here

The image was taken by Dmitry Tonkacheev, IGEM RAS, Moscow, Russian Federation.

Dmitry writes, “This is Co-bearing sphalerite, synthesised using gas transport method at 850C looks like the Christmas Tree. Although presented intergrowth of crystals was made in the laboratory, there are some natural samples, that comes from Africa. Green sphalerite from Congo can be used as jewellery.”

I have to chip in that incorporating Co into minerals can often lead to some very unsusual colours. For example, cobaltoan calcite is brilliant, neon pink.

Quartz over Malachite on Cobaltian Calcite

Cobaltoan Calcite from Katanga, Congo. (Source)