GeoLog

Hydrological Sciences

GeoTalk: Making their mark: how humans and rivers impact each other

GeoTalk: Making their mark: how humans and rivers impact each other

Geotalk is a regular feature highlighting early career researchers and their work. In this interview we speak to Serena Ceola, a hydrologist and assistant professor at the University of Bologna, Italy, who studies interactions between humans and river systems. At the upcoming General Assembly she will be recognised for her research contributions as the recipient of the 2019 Hydrological Sciences Division Outstanding Early Career Scientists Award.

Thanks for talking to us today! Could you introduce yourself and tell us a little more about your career path so far?

I was born in Padova, Italy, and studied environmental engineering at the University of Padova, from which I obtained a master’s degree in 2009. Since my bachelor’s studies, I was fascinated by hydrology: both my bachelor’s and master’s thesis dealt with the availability of river discharge, which is the amount of water flowing through a river channel.

Then, in 2009 I moved to Lausanne in Switzerland and I continued my studies with a PhD at the Laboratory of Ecohydrology of the École Polytechnique Fédérale de Lausanne (EPFL). My PhD thesis focused on the implications of river discharge availability on river ecosystems (namely algae and macroinvertebrates). Since 2013, I have been based at the University of Bologna, Italy, currently as a junior assistant professor. Now my main research project focuses on the relationship between river discharge availability and human activities, both at local and global scales.

Serena Ceola collecting benthic macroinvertebrates used for a small-scale flume experiment in Lunz-Am-See, Austria. (Photo Credits: Serena Ceola)

What got you interested in environmental engineering and hydrology? What brought you to study this particular field?

Studying environmental engineering was the perfect trade-off between being an engineer and focusing on environment sustainability and protection. During my studies I have developed a forma mentis that allows me to quantitatively solve (or try, at least) any issue. Since I was always fascinated by water, hydrology was my ideal choice. I must also say that my professors played a key role: their enthusiasm and passion overwhelmed me, involving me in such a fascinating subject.

At this year’s General Assembly, you will receive the Outstanding Early Career Scientists Award in the Hydrological Sciences Division for your contributions to understanding of the relationship between river environments and human activities. Could you tell us more about your research in this field and its importance?

River discharge has always been my main research focus. During the last 10 years, I had the unique opportunity to focus on the possible implications of river discharge .

Human activities, such as dam development, deforestation, agriculture, urbanization, etc. are known to affect how much flowing water is available to river ecosystems. In particular, I realised that no one before had conducted a quantitative analysis of how human-derived modifications to the natural flow of a river could possibly affect its environment.

Flume experimental facilities. (Photo Credits: Serena Ceola)

During my PhD, I performed an experiment by building small artificial rivers aimed at quantitatively estimating how

stream algae and macroinvertebrates respond to two flow regimes, one influenced by human activity and one unaffected. The unaffected river regime was naturally variable while the other was constant, like downstream a dam.

The experimental results were promising, thus allowing me to develop an analytical model capable of reproducing observed biological data in a real river network, also proving its applicability in presence of anthropogenic influence.

Hydrologic controls on basin-scale distribution of benthic invertebrates: study area and average habitat suitability values for a mayfly species. Image redrawn from Ceola et al., 2014, WRR, https://doi.org/10.1002/2013WR015112

When focusing on human activities, it is extremely important to estimate the interrelations between humans and waters. Here, I was lucky enough to start working with satellite data measuring the distribution of human population in space and time across the globe. By using satellite nightlight images, I analysed the spatial and temporal evolution of human presence close to streams and river. When considering extreme events like floods, I also had the opportunity to identify the regions most at risk for flood deaths and damage to infrastructure.

At the General Assembly, you plan to give a talk about working with global high-resolution datasets, such as nightlight data, to better understand how human and water systems affect each other. What are some of the possibilities made available through this kind of analysis? What doors does this research open, so to speak?

Working with global high-resolution datasets, and in particular with datasets covering several years, allows one to analyse and inspect how human processes and hydrological processes have evolved and interacted in time. This kind of analysis offers the opportunity to study how human pressure on river flows has changed over time and examine urbanization processes influenced for instance by proximity to rivers. This method also allows researchers to analyze how people move as a consequence of climatic conditions, such as extreme floods or droughts.

Spatial evolution of human presence close to stream and rivers by using satellite nightlight images. Image taken from Ceola et al., 2015, WRR, https://doi.org/10.1002/2015WR017482

Before I let you go, what are some of the biggest lessons you have learned so far as a researcher? What advice would you impart to aspiring scientists?

Based on my experience so far my first recommendation is “Be passionate!” Since you will spend a lot of time (days and nights) on a research project, it is fundamental that you love what you are doing. Although sometimes it is difficult and you cannot see any positive outcome, be bold and keep working on your ideas. Then, search for data to support your ideas and scientific achievements (although sometimes it is quite challenging and time-consuming!), but this proves that your research ideas are correct. Interact with colleagues, ask them if your ideas are reasonable and create your research network. Finally, work and collaborate with inspiring colleagues, who guide and support your research activities (I had and still have the pleasure to work with fantastic mentoring people)!

Interview by Olivia Trani, EGU Communications Officer

Imaggeo on Mondays: The best of imaggeo in 2018

Imaggeo on Mondays: The best of imaggeo in 2018

Imaggeo, our open access image repository, is packed with beautiful images showcasing the best of the Earth, space and planetary sciences. Throughout the year we use the photographs submitted to the repository to illustrate our social media and blog posts.

For the past few years we’ve celebrated the end of the year by rounding-up some of the best Imaggeo images. But it’s no easy task to pick which of the featured images are the best! Instead, we turned the job over to you!  We compiled a Facebook album which included all the images we’ve used  as header images across our social media channels and on Imaggeo on Mondays blog post in 2018 an asked you to vote for your favourites.

Today’s blog post rounds-up the best 12 images of Imaggeo in 2018, as chosen by you, our readers.

Of course, these are only a few of the very special images we highlighted in 2018, but take a look at our image repository, Imaggeo, for many other spectacular geo-themed pictures, including the winning images of the 2018 Photo Contest. The competition will be running again this year, so if you’ve got a flair for photography or have managed to capture a unique field work moment, consider uploading your images to Imaggeo and entering the 2019 Photo Competition.

A view of the southern edge of the Ladebakte mountain in the Sarek national park in north Sweden. At this place the rivers Rahpajaka and Sarvesjaka meet to form the biggest river of the Sarek national park, the Rahpaädno. The rivers are fed by glaciers and carry a lot of rock material which lead to a distinct sedimentation and a fascinating river delta for which the Sarek park laying west of the Kungsleden hiking trail is famous.

 

Melt ponds. Credit: Michael Tjernström (distributed via imaggeo.egu.eu)

The February 2018 header image used across our social media channels. The photos features ponds of melted snow on top of sea ice in summer. The photo was taken from the Swedish icebreaker Oden during the “Arctic Summer Cloud Ocean Study” in 2008 as part of the International Polar Year.

 

Karstification in Chabahar Beach, IRAN. Credit: Reza Derakhshani (distributed via imaggeo.egu.eu)

The June 2018 header image used for our social media channels. The photo was taken on the Northern coast of the Oman Sea, where the subduction of Oman’s oceanic plate under the continental plate of Iran is taking place.

 

River in a Charoite Schist. Credit: Bernardo Cesare (distributed via imaggeo.egu.eu)

A polarized light photomicrograph of a thin section of a charoite-bearing schist. Charoite is a rare silicate found only at one location in Yakutia, Russia. For its beautiful and uncommon purple color it is used as a semi-precious stone in jewelry.

Under the microscope charoite-bearing rocks give an overall feeling of movement, with charoite forming fibrous mats that swirl and fold as a result of deformation during metamorphism. It may be difficult to conceive, but these microstructures tell us that solid rocks can flow!

 

Refuge in a cloudscape. Credit: Julien Seguinot (distributed via imaggeo.egu.eu)

The action of glaciers combined with the structure of the rock to form this little platform, probably once a small lake enclosed between a moraine at the mountain side and the ice in the valley.

Now it has become a green haven in the mountain landscape, a perfect place for an alp. In the Alps, stratus clouds opening up on autumn mornings often create gorgeous light display.

 

Antarctic Fur Seal and columnar basalt Credit: Etienne Pauthenet (distributed via imaggeo.egu.eu).

This female fur seal is sitting on hexagonal columns of basalt rock, that can be found in Pointe Suzanne at the extreme East of the Kerguelen Islands, near Antarctica. This photo was the November 2018 header image for our social media channels.

 

Silent swamp predator. Credit: Nikita Churilin (distributed via imaggeo.egu.eu).

A macro shot of a Drosera rotundifolia modified sundew leaf waiting for an insect at swamp Krugloe. This photo was the January 2018 header image and one of the finalists in the 2017 Imaggeo Photo Competition.

 

Once there was a road…the clay wall. Credit: Chiara Arrighi (distributed via imaggeo.egu.eu)

The badlands valley of Civita di Bagnoregio is a hidden natural gem in the province of Viterbo, Italy, just 100 kilometres from Rome. Pictured here is the ‘wall,’ one of the valley’s most peculiar features, where you can even find the wooden structural remains of a trail used for agricultural purposes in the 19th and 20th centuries.

 

New life on ancient rock. Credit: Gerrit de Rooij (distributed via imaggeo.egu.eu).

“After two days of canooing in the rain on lake Juvuln in the westen part of the middle of Sweden, the weather finally improved in the evening, just before we reached the small, unnamed, uninhabited but blueberry-rich island on which this picture was taken. The wind was nearly gone, and the ragged clouds were the remainder of the heavier daytime cloud cover,” said Gerrit de Rooij, who took this photograph and provided some information about the picture, which features some of the oldest rocks in the world but is bursting with new life, in this blog post.

 

Cordillera de la Sal. Credit: Martin Mergili (distributed via imaggeo.egu.eu)

The photograph shows the Valle de la Luna, part of the amazing Cordillera de la Sal mountain range in northern Chile. Rising only 200 metres above the basin of the Salar de Atacama salt flat, the ridges of the Cordillera de la Sal represent a strongly folded sequence of clastic sediments and evapourites (salt can be seen in the left portion of the image), with interspersed volcanic material.

 

Robberg Peninsula – a home of seals. Credit: Elizaveta Kovaleva (distributed via imaggeo.egu.eu).

“This picture is taken from the Robberg Peninsula, one of the most beautiful places, and definitely one of my favorite places in South Africa. The Peninsula forms the Robberg Nature Reserve and is situated close to the Plettenberg Bay on the picturesque Garden Route. “Rob” in Dutch means “seal”, so the name of the Peninsula is translated as “the seal mountain”. This name was given to the landmark by the early Dutch mariners, who observed large colonies of these noisy and restless animals on the rocky cliffs of the Peninsula,” said Elizaveta Kovaleva in this blog post.

 

The great jump of the Tequendama. Credit: Maria Cristina Arenas Bautista (distributed via imaggeo.egu.eu)

Tequendama fall is a natural waterfall of Colombia. This blog post highlights a Colombian myth about the origins of the waterfall, which is tied to a real climate event.

 

If you pre-register for the 2019 General Assembly (Vienna, 07 – 12 April), you can take part in our annual photo competition! From 15 January up until 15 February, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

Imaggeo on Mondays: In-tents Icelandic sunset

Imaggeo on Mondays: In-tents Icelandic sunset

This photograph was taken at the campsite near lake Mỳvatn during a field trip to Iceland. Every year a group of students from Wageningen University travels from the Netherlands to Iceland for a weeklong excursion as part of a course on catchment hydrology. The aim of the trip is to provide students with real life examples of the processes they learned during their lectures.

After a rainy morning that day, tents and equipment were packed away as quickly as possible in order to escape the wetness. The drive took the group from the campsite in Höfn, at the foot of the Vatnajökull glacier in southeastern Iceland, along the coastal highway up north towards Myvatn. Iceland is famous for its raw and beautiful nature, with waterfalls seemingly around every corner and the imposing presence of the glaciers and volcanos in the distance.

Upon our arrival at the campsite in the evening, people begrudgingly noticed that the tents were still wet from the morning rain. The campsite was situated at the bottom of a formidable hill, which provided stunning views over the lake and landscape. Not wanting to sleep in a damp tent, a few students picked up their tents, dismantled them, went up the hill and let the evening breeze do the rest, all amid the backdrop of a stunning sunset. The desire for dry covers even outweighed the very real danger of being eaten alive by masses of midges, a known pest and hazard in these parts.

When camping there is always things that can go wrong. But for places like Iceland it is the only way to truly appreciate and experience the country’s stunning beauty and wilderness. Gazing up at the northern lights from your sleeping bag is a once-in-a-lifetime experience. While waking up in the middle of the night and having to put on boots and jacket to run to the bathroom is vexing, you might be rewarded with views of the top of the glacier that has been shrouded in clouds all day, making it seem like Zeus himself is taking a peek down from Mount Olympus to see what is going on. Iceland has to be experienced, not from a cosy hotel bed, but from a tent put up in the evening and taken down the next day. As Albert Einstein once said: “Look deep into nature, and then you will understand everything better”. Even if that means hiking up a hill and holding your tent up into the wind to dry.

By Maria Warter, PhD student at Cardiff University

 

Imaggeo on Mondays: Hole in a hole in a hole…

Imaggeo on Mondays: Hole in a hole in a hole…

This photo, captured by drone about 80 metres above the ground, shows a nested sinkhole system in the Dead Sea. Such systems typically take form in karst areas, landscapes where soluble rock, such as limestone, dolomite or gypsum, are sculpted and perforated by dissolution and erosion. Over time, these deteriorating processes can cause the surface to crack and collapse.

The olive-green hued sinkhole, about 20 m in diameter, is made up of a mud material coated by a thin salted cover. When the structures collapse, they can form beautiful blocks and patterns; however, these sinkholes can form quite suddenly, often without any warning, and deal significant damage to roads and buildings. Sinkhole formations have been a growing problem in the region, especially within the last four decades, and scientists are working hard to better understand the phenomenon and the risks it poses to nearby communities and industries.

Some researchers are analysing aerial photos of Dead Sea sinkholes (taken by drones, balloons and satellites, for example) to get a better idea of how these depressions take shape.

“The images help to understand the process of sinkhole formation,” said Djamil Al-Halbouni, a PhD student at the GFZ German Research Centre for Geosciences in Potsdam, Germany and the photographer of this featured image. “Especially the photogrammetric method allows to derive topographic changes and possible early subsidence in this system.” Al-Halbouni was working at the sinkhole area of Ghor Al-Haditha in Jordan when he had the chance to snap this beautiful photo of one of the Dead Sea’s many sinkhole systems.

Recently, Al-Halbouni and his colleagues have employed a different kind of strategy to understand sinkhole formation: taking subsurface snapshots of Dead Sea sinkholes with the help of artificial seismic waves. The method, called shear wave reflection seismic imaging, involves generating seismic waves in sinkhole-prone regions; the waves then make their way through the sediments below. A seismic receiver is positioned to record the velocities of the waves, giving the researchers clues to what materials are present belowground and how they are structured. As one Eos article reporting on the study puts it, the records were essentially an “ultrasound of the buried material.”

The results of their study, recently published in EGU’s open access journal, Solid Earth, give insight into what kind of underground conditions are more likely to give way to sinkhole formation, allowing local communities to better pinpoint sites for future construction, and what spots are best left alone. This study and further work by Al-Halbouni and his colleagues have been published in a special issue organised by EGU journals: “Environmental changes and hazards in the Dead Sea region.”

By Olivia Trani, EGU Communications Officer

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.