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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

EGU 2019: Connect at the Networking & Early Career Scientists’ Zone

EGU 2019: Connect at the Networking & Early Career Scientists’ Zone

The EGU General Assembly, the largest geoscience conference in Europe, attracts more than 15,000 participants every year. While there are countless opportunities throughout the week to meet new people and reconnect with colleagues, the convention centre can be overwhelming, especially for early career scientists (ECS) and first-time attendees.

The Networking & Early Career Scientists’ Zone (formerly called the Early Career Scientists Lounge) on the Red Level of the conference centre is the perfect place to catch up with your peers and make new connections in a more relaxed setting.

Early Career Scientists checking the notice boards at the EGU General Assembly 2018 (Credit: Stephanie Zihms)

Early career scientists across all fields are encouraged to meet there to grab a coffee, hold informal discussions and perhaps even find opportunities for collaborations. Additionally, we hope that mentors and mentees participating in the General Assembly Mentoring Programme, as well as other meeting participants interested in networking, will meet here.

Stay up-to-date

Be sure to check out the zone’s community notice boards, where you can find information on various topics, like cultural activities in Vienna and division social events, taking place during the week of the conference. Your feedback to the ECS representatives is very welcome and can be posted on the suggestion boards too. You can also post your own flyers here to highlight sessions and events taking place throughout the week.

Attend and organise pop-up events

The Networking & ECS Zone also hosts a series of pop-up style events, from using poetry to communicate your science to giving research elevator pitches. Be sure to check out the notice boards to find more info on what drop-in sessions are scheduled for the week.

Interested in holding your own drop-in session? Participants are encouraged to organise pop-up events in the zone as well! A whiteboard, flipchart, and 42” screen with a notebook attached will be available in the main room for attendees to give ad-hoc presentations, plus two side room ‘pop-up spots’ can be used to hold informal sessions.

If you’d like to add a drop-in session to our schedule, you can contact the EGU communications officer with the pop-up event title, date, and time by 18 March. If you’d rather hold an impromptu session, such as a follow-up event to an over-subscribed short course, never fear! During the conference you can plan and host informal events on the spot; a sign-up sheet on the zone’s notice boards will be available for advertising drop-in sessions.

The EGU General Assembly is taking place in Vienna, Austria from 7 to 12 April. Check out the full session programme on the General Assembly website and follow the Assembly’s online conversation on Twitter (#EGU19 is the official conference hashtag) and Facebook.

Making a poster or PICO presentation: top tips from the Outstanding Student Poster and PICO (OSPP) Award judges

Making a poster or PICO presentation: top tips from the Outstanding Student Poster and PICO (OSPP) Award judges

Every year at the General Assembly hundreds of students present their research at the conference with a lot of time and effort going into preparing these presentations. With the aim to further improve the overall quality of poster presentations and more importantly, to encourage early career scientists to present their work in the form of a poster, the OSP Awards (as they were formerly known), were born. Since the 2016 General Assembly, PICO presentations have been included in the Outstanding Student Poster Awards, which have been renamed to Outstanding Student Poster and PICO (OSPP) Awards.

“There are a thousand posters in a hall, and they are all competing for attention,” highlights Niels Hovius of GFZ, German Research Centre for Geosciences and a former OSP Judge for the Geomorphology Division, “so, you need to stand out a little bit.”

But, how can you make sure your poster or PICO is a great presentation which achieves that?

At the 2015 General Assembly we spoke to some of the judges and past winners of the award and asked them to share their thoughts on what makes a top poster presentation.  We put their top tips together in this short video, which gives you a good idea of the key elements you ought to be thinking about when preparing your poster or PICO presentation.

If you are participating in OSPP, don’t forget to attach the OSPP label (blue SVGblue PNGyellow SVGyellow PNG) to your poster board. Alternatively, you might include the label in the poster itself. If you participate with a PICO, you are kindly asked to add the OSPP label to your PICO presentation header.

The OSP awards are presented at the level of the EGU Programme Groups which in 2015 saw an improved way of signing up for the award and also judging of the presentations. A post from the blog archives also has full details of how the presentations are evaluated and you can also find detailed information about the award on the EGU website.

The EGU General Assembly is taking place in Vienna, Austria from 7 to 12 April. Check out the full session programme on the General Assembly website and follow the Assembly’s online conversation on Twitter (#EGU19 is the official conference hashtag) and Facebook.

GeoTalk: the climate communication between Earth’s polar regions

GeoTalk: the climate communication between Earth’s polar regions

Geotalk is a regular feature highlighting early career researchers and their work. In this interview, we caught up with Christo Buizert, an assistant professor at Oregon State University in Corvallis, who works to reconstruct and understand climate change events from the past. Christo’s analysis of ice cores from Greenland and Antarctica helped reveal links between climate change events from the last ice age that occurred on opposite ends of the Earth. At this year’s General Assembly, the Climate: Past, Present & Future Division recognized his innovative contributions to palaeoclimatology by presenting him with the 2018 Division Outstanding Early Career Scientists Award.

Christo, thank you for talking to us today! Could you introduce yourself and tell us about your career path so far?

Thanks for having me on GeoTalk! I’m a palaeoclimate scientist working on polar ice cores (long sticks of ancient ice drilled in Greenland and Antarctica), combining data, modeling and fieldwork. My background is in physics, and I did a MSc thesis project on quantum electronics. As you can see, I ended up in quite a different field. After teaching high school for a year in my home country the Netherlands, I pursued a PhD at the Niels Bohr Institute in Copenhagen, Denmark, working on ice cores. I must say, doing a PhD is a lot easier than teaching high school! I have gained a lot of respect for teachers.

After obtaining my PhD I moved to the US for reasons of both work and love (not necessarily in that order). I got a NOAA Climate & Global Change Postdoctoral Fellowship at Oregon State University (OSU). OSU has a great palaeoclimate research group and Oregon is one of the prettiest places on Earth, so the decision to stick around was an easy one.

What inspired you to pursue palaeoclimatology after getting your MSc degree in quantum electronics?

I wish I had a better answer to this question, but the truth is that I was drawn by the possibility of doing fieldwork in Greenland, mainly.

At the General Assembly, you received a Division Outstanding Early Career Scientist Award for your work on understanding the bi-polar phasing of climate change. For those of us who aren’t familiar, could you elaborate on this particular field of study?

The final drill run of the WAIS Divide ice core, with ice from 3,405 m (11,171 ft) depth that has been buried for 68,000 years. (Credit: Kristina Slawny/University of Bern)

During the last ice age (120,000 to 12,000 years ago), the world experienced some of the most extreme and abrupt climate events that we know of, the so-called Dansgaard-Oeschger (D-O) events. About 25 of these D-O events happened in the ice age, and during each of them Greenland warmed by 8 to 15oC within a few decades. Each of the warm phases (called interstadials) lasted several hundreds to thousands of years. Greenland ice cores provide clear evidence for these events.

The abrupt D-O events are thought to be linked to changes in ocean circulation. Heat is transported to the Atlantic Ocean by the Atlantic Meridional Overturning Circulation (AMOC) from the southern hemisphere to the northern hemisphere. The AMOC keeps the Nordic Seas free of sea ice and effectively warms Greenland, particularly during the winter months. However, the strength of this heat circulation went through abrupt changes during the last ice age. Marine sediment data and model studies show that changes to the AMOC strength caused the extreme temperature swings associated with the D-O events.

During weak phases of the AMOC, less heat and salt are brought to the North Atlantic, leading to expansive (winter) sea ice cover and cold conditions in Greenland. These are the D-O cycle’s cold phases, the so-called stadials. And vice versa, during the AMOC’s strong phases, the ocean transports more heat northwards, reducing sea ice cover and warming Greenland. These are the warm (interstadial) phases of the D-O cycle.

When the AMOC is strong, it warms the northern hemisphere at the expense of the southern hemisphere. This inter-hemispheric heat exchange is sometimes referred to as ‘heat piracy,’ since the North Atlantic is ‘stealing’ heat from the southern hemisphere. So when Greenland is warm, we see Antarctica cool, and when Greenland is cold, Antarctica is warming. These opposite hemispheric temperature patterns are called the bipolar seesaw, after the playground toy. Using a new ice core from the West Antarctica Ice Sheet (the WAIS Divide ice core), we were able to study the relative timing of the bipolar seesaw at a precision of a few decades – which is extremely precise by the standards of palaeoclimate research.

An infographic explaining the opposite hemispheric temperature patterns, also known as the bipolar seesaw (Illustration by David Reinert/Oregon State University).

We found that the temperature response to the northern hemisphere’s abrupt D-O events was delayed by about two centuries at WAIS Divide. This finding shows that the effects of these D-O events start in the north, and then are transmitted to the southern high-latitudes via changes in the ocean circulation. If the atmosphere were responsible, transmission would have been much faster (typically within a year or so). State-of-the-art climate models actually fail to simulate this 200-year delay in the Antarctic response, suggesting they are missing (or overly simplifying) some of the relevant physics of how temperature anomalies are propagated and mixed in the global ocean. The timescale of two centuries is unmistakably the signature of the ocean, in my view, and so it is an interesting target for testing models.

At the meeting you also gave a talk about the climatic connections between the northern and southern hemispheres during the last ice age. Could you tell us a little more about your findings and their implications? 

A volcanic ash layer in an Antarctic ice core. Volcanic markers like these were used in the new study to synchronize ice cores from across Antarctica. (Credit: Heidi Roop/Oregon State University)

I presented some recently published work that elaborates on this 200-year delay mentioned earlier. Together with European colleagues, we synchronized five Antarctic ice cores using volcanic eruptions as time markers. This makes it possible to study the timing of the seesaw across the entire Antarctic continent with the same great precision as at WAIS Divide. It turns out that the 200-year delayed oceanic response to the northern hemisphere’s abrupt climate change is visible all over Antarctica, not just in West Antarctica.

But the exciting thing is that by looking at the spatial picture, we detect a second mode of climatic teleconnection, superimposed on the bipolar seesaw we talked about earlier. This second mode has zero-time lag behind the northern hemisphere, suggesting that this mode is an atmospheric teleconnection pattern. In my talk I used postcards and text messages as an analogy for these two modes. The oceanic mode is like a postcard, that takes a long time to arrive in Antarctica (200 years). The atmospheric mode is like a text message that arrives right away.

The atmospheric circulation change (the “text message”) causes a particular temperature pattern over Antarctica, with cooling in some places and warming in others. Think of this as the “fingerprint” of the atmospheric circulation. We then compared the ice-core fingerprint to the fingerprints of several wind patterns seen in modern observations. We found that the so-called Southern Annular Mode, a natural mode describing the variability of the westerly winds circling Antarctica, is the best modern analog for what we see in the ice cores.

An infographic explaining how Earth’s polar regions communicate with each other (Illustration by Oliver Day/Oregon State University)

Another piece of the puzzle is that atmospheric moisture pathways to Antarctica change simultaneously with the atmospheric mode. All this supports the idea that the southern hemisphere’s westerly winds respond immediately to abrupt climate change in the North Atlantic. When D-O warming happens in Greenland the SH westerlies shift to the north, and vice versa, during D-O cooling they shift to the south.

This had been predicted in models, and some limited evidence was available from the WAIS Divide ice core, but the new results provide the strongest observational evidence for this effect. This movement of the westerlies has important consequences for sea ice, ocean circulation, and perhaps even CO2 levels and ice sheet stability. So it really urges us to look at these D-O cycle in a global perspective.

You’ve enjoyed success as a researcher, not least your 2018 EGU Award. As an early career scientist, do you have any words of advice for graduate students who are hoping to pursue a career as a scientist in the Earth sciences?

I’m sure there are many different routes to becoming a successful researcher. Developing your own ideas and insights is key, and the secret to having good ideas is having many ideas, because most of them end up being wrong! So be creative and go out on a limb. I am lucky to have had supervisors who gave me a lot of freedom to explore my own ideas. I would also encourage everybody to develop skills in programming and numerical data analysis, for example in Matlab or python.

Christo Buizert (right) and Didier Roche, President of the Climate: Past, Present & Future Division, (left) at the EGU 2018 General Assembly (Credit: EGU/Foto Pflugel).

Frustrating and unfair as it may be, luck plays an important role in getting your research career started. My main PhD project did not work out, but I had a very productive postdoc that grew out of a side project. I ended up in the right place at the right time, because the WAIS Divide ice core had just been drilled, and I got the privilege to work with some of the best ice core data ever measured.

Research is fundamentally a collaborative enterprise, and so developing a good network of collaborators is maybe the most important thing you can do for yourself. Be generous and helpful to your colleagues, and it will be rewarded.

A career in science sometimes feels like a game of musical chairs, with fewer and fewer positions available as you go along. But if you can hang in there it’s definitely worth it; we have the privilege of thinking about interesting problems, traveling to beautiful places, all while interacting with a global network of fantastic colleagues. Could it get much better?

Interview by Olivia Trani, EGU Communications Officer