Hydrological Sciences

Celebrating Earth Science Week!

Celebrating Earth Science Week!

For those not so familiar with the Earth sciences, geosciences and all its subdisciplines might be shrouded in mystery:  boring, unfathomable, out of reach and with little relevance to everyday life. Nothing could be further from the truth!

Earth Science Week, an international annual celebration founded by the American Geosciences Institute in 1998, aims to change the public’s perception of the geosciences.  Since 2011, the London Geological Society also hosts a range of events and activities to raise awareness and better understanding of the Earth sciences.

In 2016, Earth Science Week takes place between 8 and16 October. For the first time, the EGU will run events to mark the special date, all of which we invite you to take part in!

Earth Science Week Photo Competition

From Wednesday 5th to Friday 14th October submit an original photo on any broad theme related to the Earth, planetary and space sciences to our open access image repository, Imaggeo.

For your image to be included in the competition be sure to include the tag #EarthSciWeek when prompted during the upload.

Upon the submission period closing, all entered images will be published to the EGU’s Facebook page. The photograph with most likes, as chosen by the public, will be crowned the competition winner.

The winner will get one free book of their choice from the EGU library and a pack of EGU goodies! We’ll also feature the top five most popular entries on our Instagram.

I’m a geoscientist – Ask me Anything: Live Twitter Q&As

Have you always wanted to know how glaciers move and carve out unbelievable landscapes? How about which emissions cause the most pollution? What are the benefits of publishing in an open access journal vs. a pay-walled publication? If politicians make all the decisions, how can we get them to take scientists more seriously?

If you’ve ever asked yourself these questions, stay tuned or, better still, take part in our daily Earth Science Week live #EGUchat with an EGU member on Twitter. Starting on Monday, every lunchtime, you’ll have the opportunity to put your questions to a range of scientists and EGU experts and discuss a variety of subjects.

Our very own Sarah Connors (@connors SL), the EGU’s Policy Fellow, will kick off a week, of what we hope will be fruitful discussions, by taking questions on all things science policy. Come Tuesday Emma Smith (@emma_c_smith) and Nanna Karlsson (@icymatters), Cryosphere Division Blog editors, will team up to shed light on the processes which operate in the iciest places on the planet.

Wednesday brings editor of the EGU’s open access journal Earth Surface Dynamics (ESurf) and Professor of Physical Geography at the University of Hull, Tom Coulthard (@Tom_Coulthard), who will shed light on the processes which shape our planet and the trials and tribulations of getting published.

If you are interested in natural hazards, how we mitigate, manage them and how they impact on our daily lives, then tune in to the chat on Thursday, where Giorgio Boni (@EguNHpresident), President of the Natural Hazards Division will be answering all your questions!

For the final chat of the week, we bring you Michelle Cain (@civiltalker), an atmospheric scientist and former Atmospheric Division Early Career Scientist Representative. Michelle will be taking questions on gaseous emissions and topics related to the Earth’s atmosphere.

Joining the conversation couldn’t be easier! To put your questions to our experts follow the hashtag #EGUchat on Twitter. Not on twitter or aren’t available during the chats? Not to worry, send us your questions in the comments below or via Twitter, Facebook or Instagram: we’ll ask the experts on your behalf.earth_sci_week_ama_twitter-01


Imaggeo on Mondays: Living flows

Imaggeo on Mondays: Living flows

There are handful true wildernesses left on the planet. Only a few, far flung corners, of the globe remain truly remote and unspoilt. To explore and experience untouched landscapes you might find yourself making the journey to the dunes in Sossuvlei in Namibia, or to the salty plain of the Salar Uyuni in Bolivia. But it’s not necessary to travel so far to discover an area where humans have, so far, left little mark. One of the last wilds is right here in Europe, in the northern territories of Sweden. Today’s spectacular photograph of the Laitaure delta is brought to you by Marc Girons Lopez, one of the winners of the 2016 edition of the EGU’s Photo Contest!

The photograph shows a part of the Laitaure delta, at the entrance of Sarek National Park (Northern Sweden). Sarek is one of the oldest national parks in Europe and it is often considered to be one of the last wild areas in Europe. The Sami people, however, have traditionally used these lands.

This delta is formed by the Rapa River when it flows into Lake Laitaure. The Rapa River springs from the Sarektjåkkå glacier and is fed by over thirty glaciers. The specific flow of the Rapa River — the ratio between its flow and the area of its catchment — is the highest in Sweden. The magnitude of the flow has strong seasonal fluctuations which are reflected in the sediment transport, which can be as high as 10,000 tons per day during the summer. This heavy sediment load gives the river its characteristics greyish colour. The different colours in the backwater zones may be produced by dissolved organic matter from decomposing vegetation.

The delta in this area is flanked by  patches of montane forests along the river banks in an area otherwise covered by marshes. Regarding the fauna, according to Wikipedia the Eurasian teal, the Eurasian wigeon, the greater scaup, the red-breasted merganser, the sedge warbler and the common reed bunting are common in the Laitaure delta.

By Marc Girons Lopez, researcher at the Centre for Natural Disaster Science, Uppsala University

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


Geosciences Column: The World’s soils are under threat

Geosciences Column: The World’s soils are under threat

An increasing global population means that we are more dependant than ever on soils.

Soils are crucial to securing our future supplies of water, food, as well as aiding adaptation to climate change and sustaining the planet’s biosphere; yet with the decrease in human labour dedicated to working the land, never have we been more out of touch with the vital importance of this natural resource.

Now, the first-ever comprehensive State of the World’s Soil Resources Report (SWRS), compiled by the Intergovernmental Technical Panel on Soils (ITPS), aims to shine a light on this essential non-renewable resource. The report outlines the current state of soils, globally, and what the major threats facing it are. These and other key findings of the report are summarised in a recent paper of the EGU’s open access Soil Journal.

The current outlook

Overall, the report deemed that the world’s soils are in fair to very poor condition, with regional variations.  The future doesn’t look bright: current projections indicate that the present situation will worsen unless governments, organisations and individuals come together to take concerted action.

Many of the drivers which contribute to soil changes are associated with population growth and the need to provide resources for the industrialisation and food security of growing societies. Climate change presents a significant challenge too, with factors such as increasing temperatures resulting in higher evaporation rates from soils and therefore affecting groundwater recharge rates, coming into play.

The three main threats to soils

Soil condition is threatened by a number of factors including compaction (which reduces large pore spaces between soil grains and restricts the flow of air and water into and through the soil), acidification, contamination, sealing (which results from the covering of soil through building of houses, roads and other urban development), waterlogging, salinization and losses of soil organic carbon (SOC).

Global assessment of the four main threats to soil by FAO regions. Taken from Montanarella, L., et al. 2016.

Global assessment of the four main threats to soil by FAO regions. Taken from Montanarella, L., et al. 2016.

Chief among the threats to soils is erosion, where topsoil is removed from the land surface by wind, water and tillage. Increasing rates of soil erosion affect water quality, particularly in developed regions, while crop yields suffer the most in developing regions. Estimating the rates of soil erosion is difficult (especially when it comes to wind driven erosion), but scientists do know that topsoil is being lost much faster than it is being generate. This means soil should be considered a non-renewable resource. When it comes to agricultural practices in particular, soils should be managed in such a way that soil erosion rates are reduced to near zero-values, ensuring long-term sustainability.

Eutrophication in lake Slotsø, Kolding, Denmark. Credit: Alevtina Evgrafova (distributed via

Eutrophication in lake Slotsø, Kolding, Denmark. Credit: Alevtina Evgrafova (distributed via

Soils contain nutrients, such as nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulphur (S), crucial for growing crops and pastures for raising cattle. While nutrient balance in soils has a natural variability, farming practices accelerate changes in soil nutrient content. Over-use of soils rapidly depletes the land-cover of nutrients and result in lower food production yields. This imbalance is often remedied by the addition of nutrients; in particular N and P. Excessive use of these practices, however, can lead to negative environmental effects, such as eutrophication (which increases the frequency and severity of algal blooms) and contamination of water resources. The findings of the report advocate for the overall reduction of use of fertilisers, with the exception of tropical and semi-tropical soils in regions where food security is a problem.

Carbon (C) is a fundamental building block of life on Earth and the carbon cycle balances the amount of C which ultimately enters the atmosphere, helping to stabilise the planets temperature. Soils play a significant role in helping to preserve this balance. Soil organic carbon (SOC) acts as a sink for atmospheric C, but converting forest land to crop land saw a decrease of 25-30% in SOC stocks for temperate regions, with higher losses recorded for the tropics. Future climate change will further affect SOC stocks through increased temperatures and fluctuating rainfall, ultimately contributing to risks of soil erosion and desertification and reducing their ability to regulate carbon dioxide emissions. It is vitally important that governments work towards stabilising, or better still, improving existing SOC stocks as a means of combating global warming.

Preserving a valuable resource

The case is clear: soils are a vital part of life on Earth. It is estimated that worsening soil condition will affect those already most vulnerable, in areas affected by water scarcity, civil strife and food insecurity.

Bed planting in northern Ethiopia. Credit: Elise Monsieurs (distributed via

Bed planting in northern Ethiopia. Credit: Elise Monsieurs (distributed via

Initiatives such as the 2015 International Year of Soil and the production of the SWRS report are fundamental to raise awareness of the challenges facing soil resources, but more needs to be done:

      1. Sustainable soil management practices, which minimise soil degradation and replenish soil productivity in regions where it has been lost, must be adopted to ensure a healthy, global, supply of food.
      2. Individual nations should make a dedicated effort to establish appropriate SOC-improving strategies, thus aiding adaptation to climate change.
      3. Manging the use of fertilisers, in particular N and P, should be improved.
      4. There is a dearth of current data, with many of the studies referenced in the SWRS report dating from the 1980s and 1990s. For accurate future projections and the development and evaluation of tools to tackle the major threats facing soils, more up-to-date knowledge about the state of soil condition is required.

Soils, globally, are under threat and their future is uncertain. The authors of report argue that “the global community is presently ill-prepared and ill-equipped to mount an appropriate response” to the problem. However, adoption and implementation of the report findings might (by policy-makers and individuals alike) just turn the tide and ensure soils remain “humanity’s silent ally”.

By Laura Roberts Artal, EGU Communications Officer


Montanarella, L., Pennock, D. J., McKenzie, N., Badraoui, M., Chude, V., Baptista, I., Mamo, T., Yemefack, M., Singh Aulakh, M., Yagi, K., Young Hong, S., Vijarnsorn, P., Zhang, G.-L., Arrouays, D., Black, H., Krasilnikov, P., Sobocká, J., Alegre, J., Henriquez, C. R., de Lourdes Mendonça-Santos, M., Taboada, M., Espinosa-Victoria, D., AlShankiti, A., AlaviPanah, S. K., Elsheikh, E. A. E. M., Hempel, J., Camps Arbestain, M., Nachtergaele, F., and Vargas, R.: World’s soils are under threat, SOIL, 2, 79-82, doi:10.5194/soil-2-79-2016, 2016.

Status of the World’s Soil Resources, 2015, Food and Agricultire Organization (FAO) of the United Nations.

Soils are endangered, but degradation can be rolled back, 2015, FAO News Article.

Imaggeo on Mondays: Why is groundwater so important?

Imaggeo on Mondays: Why is groundwater so important?

Groundwater is an often underestimated natural resource, but it is vital to the functioning of both natural and urban environments. Indeed, it is a large source of drinking water for communities world-wide, as well as being heavily used for irrigation of crops and crucial for many industrial processes. The water locked in the pores and cracks within the Earth’s soils and rocks, also plays an important role in the recharge of water in lakes, rivers and wetlands, as Anna Menció explains in today’s Imaggeo On Monday’s post.

The Pletera salt marsh area (NE Spain) is located in the north of the mouth of the Ter River, in a region mainly dominated by agriculture and tourism activities. Some of the coastal lagoons and wetlands in this area have been affected by the incomplete construction of an urban development. These wetlands and lagoons are the focus of a Life+ project, which aims to restore this protected area, and to recover its ecological functionality.

The Pletera coastal lagoons are periodically flooded by both, freshwater from streams and seawater, during storm events. However, the surface water inputs alone are insufficient to maintain them as permanent lagoons.

This picture is of Fra Ramon lagoon, one of the natural lagoons in the area. The preliminary results of a recent study showed that the recharge of Fra Ramon is dependent on groundwater inputs. In most of the sampling campaigns, freshwater from the aquifer may account for >50% of the lagoon water.

The ecological quality of these lagoons is also affected by nitrogen inputs, mainly produced during flooding events. Although in this area nitrate pollution is also detected in groundwater, with concentrations up to 100 mg NO3/L, natural attenuation processes in the aquifer occur. Effects of these processes are particularly detected close to the lagoons area, where low nitrate concentrations in groundwater are observed, with values below the detection limit. Considering that groundwater may present lower nitrogen concentrations than surface inputs observed during flooding events, these results reinforce the importance of groundwater dynamics in these systems, not only to maintain the permanent lagoons during dry periods, but also to preserve their quality.

By Anna Menció, researcher at the Department of Environmental Sciences of the University of Girona.

Acknowledgments: the study of the Pletera coastal lagoons is founded by LIFE 13 NAT/ES/001001, MINECO CGL-2014-57215-C4-2R, and UdG MPCUdG2016/061 projects.


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


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