Geology for Global Development

Bárbara Zambelli Azevedo

Speleology and local development

Križna jama cave, in Slovenia

Many of us seek adventures, new experiences and sights in far flung places, but very often there are beautiful wonders right on our doorstep. In today’s post, Barbara Zambelli Azevedo highlights how the promotion of local geological regions can be a valuable and effective way to encourage development and instil a sense of pride in local communities. 

Plato said in the Allegory of the Cave that men could only be free from ignorance when they leave the shadow world and see the real world outside. For me, caves have the opposite meaning. My first time in a cave at the end of 2011 changed me forever. To see the beauty hidden in the dark, countless endogenous species and curious formations in such a delicate and unique environment, thrilled me.

I was touched by speleology and I think that other people may feel the same. Even though karst areas are common throughout the world, still many people don’t know anything about caves, nor have they ever been in one. I believe in valorisation and promotion of speleological heritage in karstic areas as a way to promote sustainable territorial development. This could be done combining four different approaches:

Tourism: Implementation of a speleological management plan allowing and regulating public visitation, seeking at the same time the conservation of the cave, its surroundings and its attributes (physical and biological) as well as the transformations it might need to receive the general public. These transformations could be stairs, handrail, lights, bridges and walkways. It is important to consult the local community before starting any kind of business to know if the chosen cave has a special meaning, if it represents a sacred place or it is part of their culture.

Conservation: Conservation practices must be adopted to ensure the preservation of the speleological heritage. Cave guides should come preferably from the local community. They must receive appropriate training and instruction about security during exploration and conservation of the karst. In Brazil we use the motto:

“In a cave nothing is taken away except photographs, nothing is left but tracks and nothing is killed except time.”

Parks: Implementation of parks in areas where caves are concentrated in a given territory. This territory can be at local or regional level, and the park administration takes charge of the preservation and management of the speleological heritage.

Education: Promote local empowerment through science communication and environmental education. As I mentioned before, there are not a lot of people who know about speleology. In this context it is important to assess the knowledge of the local community when it comes to karst, caves and their formation, as well as their unique fauna, the delicate and complex hydrologic system. When a population is aware of its heritage, is more likely they will ensure its preservation.

Finally, it is crucial to highlight that before starting any kind of business regarding speleology, many different interdisciplinary and multidisciplinary studies must be carried on the areas, in order to select the most appropriate ones for developing tourism or any other activities.

Saltwater intrusion: causes, impacts and mitigation

In many countries, access to clean and safe to drink water is often taken for granted: the simple act of turning a tap gives us access to a precious resource. In today’s post,Bárbara Zambelli Azevedo, discusses how over population of coastal areas and a changing climate is putting ready access to freshwater supplies under threat. 

Water is always moving downwards, finding its way until it gets to the sea. The same happens with groundwater. In coastal areas, where fresh groundwater from inland meets saline groundwater an interesting dynamic occurs. As salt water is slightly denser than freshwater, it intrudes into aquifers, forming a saline wedge below the freshwater. This boundary is not fixed, it shows seasonal variations and daily tidal fluctuations. It means that this interface of mixed salinity can shift inland during dry periods, when the freshwater supply decreases, or seaward during wetter months, when the contrary happens.

Freshwater and saltwater interaction. Credit: The National Environmental Education and Training Foundation (NEEF).

Once saline groundwater is found where fresh groundwater was previously, a process known as saltwater intrusion or saline intrusion happens. Even though it is a natural process, it can be influenced by human activities. Moreover, it can become an issue if saltwater gets far enough inland that it reaches freshwater resources, such as wells.

According to the UN report, about 40% of world’s population live within 100km from the coastline or in deltaic areas. A common source of drinking water for those coastal communities is pumped groundwater. If the demand for water is higher than its supply, as can often occur in densely populated coastal areas, the water pumped will have an increased salt content. As a result of overpumping, the groundwater source gets contaminated with too much saltwater, being improper for human consumption.

With climate change, according to the IPCC Assesment Reports, we can expect  sea-level to rise, more frequent extreme weather events, coastal erosion, changing precipitation patterns and warmer temperatures. All of these factors combined with the a increased demand for freshwater, as a result of global population growth, could boost the risk of saltwater intrusion.

Shanghai – an example of densely-populated coastal city. By Urashimataro (Own work) [CC BY-SA 3.0 ],via Wikimedia Commons.

Although small quantities of salt are important for regulating the fluid balance of the human body, WHO advises that consuming higher quantities of salt than recommended can be associated with adverse health effects, such as hypertension and stroke. In this manner, reducing salt consumption can have a positive effect in public health, helping to achieve SDG 3.

With the aim of preserving fresh groundwater resources for coastal communities at present and in the future, dealing with the threat of saline intrusion is becoming more and more important.

Therefore, to be able to mitigate the problem, first of all, it needs to be better understood. This can be done by characterising, modelling and monitoring aquifers, assessing the impact and then drawing solutions. Currently there are many mitigation strategies being designed worldwide. In Canada, for example, the adaptation options rely on monitoring and assessment, regulation and engineering. In the UK, on the other hand, the simpler solution adopted is reducing or rearranging the patterns of groundwater abstraction according to the season. In Lebanon, a fresh-keeper well was developed as an efficient, feasible, profitable and economically attractive way to provide localised solution for salination.

Every case should be analysed according to its own characteristics and key management strategies adopted to ensure that everyone has access to clean and safe water until 2030 – SDG6.

Bárbara Zambelli Azevedo: Phosphorus Crisis – A Food Crisis?

Take a look and try to identify anything around you that has phosphorus as a component.

Phosphorus – the P element – is critical for life, like oxygen, nitrogen and carbon, being present in every plant, animal and bacteria. It constitutes cell walls, DNA, RNA and ATP, which transports energy to the brain. Our bones and teeth include phosphorus.

Now look again and you might see that phosphorus is more present in your daily life than you first imagined.

We obtain our phosphorus by eating plant- and animal-based food. Cattle obtain their phosphorus from feed, grazing and supplements. On the other hand, plants obtain phosphorus from the soil by their roots, transporting, absorbing and storing it to where it is needed. If a plant doesn’t get enough P, their growth is strongly affected, the formation of fruits and seeds decreases and crops yield less.

Image 1: Coffee crops in Minas Gerais, Brazil (photo: Bárbara Zambelli)

Image 2: Banana crops in Gran Canária, Spain (photo Bárbara Zambelli)

The phosphorus (P) present in soils is either natural or added by the use of fertilisers, manure and organic residues. Natural P exists on soils as a result of phosphatic bedrock weathering. As a geological feature, it is not evely distributed on the Earth’s surface and it can take a long time to form, such as a million years.

Why should we worry about phosphorus?

Phosphorus is a non-renewable resource that cannot be replaced or synthesized for plant nutrition. Moreover, it is one of the most reactive nutrients in the soil, being easily transformed into forms that are unavailable to plants. A study shows that about 90% of all the phosphorus mined worldwide is used for food production. According to USGS, 88% of all reserves are under control of 5 countries: Morocco, China, Algeria, Syria and South Africa. Morocco is by far the country with the largest reserve, holding 74% of the world’s phosphate reserves. Therefore, most of the countries rely on phosphorus imports to sustain agriculture. The scarcity scenario is not only physical but also geopolitical, economical and managerial.

Image 3: phosphorus mine (photo: Alexandra Pugachevsky, source)

The world’s population is growing steadily, projected to reach 9.7 billion people by 2050. In this sense, feeding almost 2 billion new mouths by 2050 is an increasing challenge. Growing food demand equals growing phosphorus demand.

The reserves of phosphorus will be depleted sooner or later. Some authors argue that the ‘phosphorus peak’ will happen pretty soon, in 2030, while others says that it won’t happen before 2100. There is no consensus because different studies are based on different methodologies and assumptions about demand and uncertainties about supply.

In this manner, to achieve SDG 2 and assure that everyone has access to safe and affordable food until 2030, we must change the way we use, source and distribute phosphorus among the global food production.

Another important issue is the biofuels production. With an increasing pressure to reduce oil consumption and greenhouse gases emissions, accordingly to the Paris Agreement on COP21, many countries are turning to biofuels, such as alcohol made from maize or sugarcane. These crops also needs phosphorus and use land that could be used for agricultural purposes.

What about the environment?

While phosphorus is a scarce resource vital for agriculture, it is also a pollutant of waterbodies. Not all phosphorus used as fertiliser is absorbed by plants. Some phosphorus stays on the soil and is later carried to streams, rivers and lakes. This anthropogenic input of phosphorus generates an anomalous concentration of P nutrient in water bodies, encouraging the growth of blue and green algal and causing algal blooms. The increase of nutrients and then algae and higher plants is called eutrophication.

Eutrophication can be toxic or deeply change the ecology of the waterbody. It produces many undesirable effects regarding human society, such as drinking water problems, decrease of seafood production and presence of toxins in drinking water and seafood.

Image 4: eutrophication at a wastewater outlet in Potomac River, Washngton D.C. (photo: Alexandr Trubetskoy, source)

Another environmental problem concerns mining tailings. Phosphatic rocks, as a result of its chemical composition, may contain notable amounts of naturally occurring radioactive materials. The process of converting the phosphorus ore to phosphoric acid (that can be used as fertiliser) or elemental phosphorus produces phosphogypsum as a primary waste by-product. These processes concentrate in the waste most of the naturally occurring thorium and uranium and its decay products, such as radium and radon. If proper attention is not given to this waste, it risks contaminating the air with radon gas (radioactive), and groundwater, affecting farmers and the wider population.

What can we do?

We have to think in ways to reduce the consumption, reuse and recycle.

A simple way for reduce phosphorus consumption is actually not a brand new idea. The answer relies on the symbiotic association between a small fungus and plants’ roots called ‘mycorrhizal’. The symbiose, which is a win-win relation, occurs when the fungus bounds to the roots. This fungus grows faster and it is more efficient on searching for phosphorus than the plants’ roots. So it provides phosphorus that were on the soil but could not be absorbed by the plant and, in return the plant nourishes it. Therefore, by using mycorrhizal association it possible to reduce the amount of phosphorus fertilisers needs of a crop, by enhancing its P absorption by the plant. In this video, Dr Mohamed Hijri explore use of mycorrhiza to optimise phosphorus use for agricultural purposes. Another way of reducing consumption would be encouraging diets that has fewer aliments that are phosphorus intenses, like meat and dairy products.

About reuse, we can think on reducing losses on the food chain, rubbish bin and animal manure, for example. Those are all sources of phosphate that cannot be overseen.

Concerning recycling, it is important to highlight the safe use of wastewater for agricultural purposes. The UN-Water has a project on this issue can be downloaded here. Its usage is already bigger than expected! Almost 100% the phosphorus eaten in food is excreted. The sewage treatment as a way to recover phosphorus present in human screta for agriculture, although controversial, is already being done in Sweden for example. Since the population is growing and a big part of it will settle down in peri-urban areas in mega-cities in the next few years, a big attention must be given to these places. They are becoming a ‘hotspot’ for phosphate production.

To know more about the phosphorus crisis and opportunities click here, here and here.

Bárbara Zambelli Azevedo: Access​ ​to​ ​clean​ ​water,​ ​gender​ ​equality​ ​and​ ​geosciences

The importance of access to safe drinking water in our lives is quite obvious. Although its relation with gender equality and sustainable development may be less so. In this article, Bárbara Zambelli Azevedo explores the relationship between the two and discusses what geoscientists can do to improve the situation.

In 2017, according to the WHO, over 2.1 billion people still don’t have access to safely managed water (“safely managed drinking water means drinking water free of contamination that is available at home when needed”). It represents 3 out of 10 people worldwide! This number also includes 844 million people that don’t even have a basic drinking water service (more than Europe’s entire population), 263 million who have to spend over 30 minutes per trip outside their homes collecting water and 159 million who still drink untreated surface waters.

Daily collection of water in Tanzania (Credit: Joel Gill, distributed via

Target 6.1 of Sustainable Development Goal 6 states “by 2030, achieve universal and equitable access to safe and affordable drinking water for all”. Here is a map showing the progress of access to water from 1990 to 2017 and projections to 2030.

But how does the lack of access to water impact women’s lives? Around the world, in many societies, women and girls are more likely to be responsible for the collection and management of household water supply, sanitation and health. Water is not only used for drinking and cooking purposes but also for cleaning, laundry, personal hygiene, and care of domestic animals, among other uses. Because of their dependence on water resources, women are also unduly affected by water scarcity, climate change and disasters.

Groundwater in India

According to the World Bank, India uses approximately 230km³ per year of groundwater, being the largest user of groundwater worldwide. Over 85% of drinking water comes from groundwater sources.

This exploitation of groundwater is causing a scenario of scarcity of agricultural and drinking water, especially during drought years, in both Guajarat and Rajasthan watersheds. Those watersheds have hard rock aquifers, with low connectivity, limited storage capacity and large groundwater fluctuations. In Dharta watershed (Rajasthan), groundwater trends from the past 20 years are showing a net rate of groundwater depletion. A survey took place in eight secondary schools located in Rajasthan and Guajarat watersheds in semi-arid regions in India, relating groundwater scarcity to school absenteeism of female students. The main objective was to assess students’ perceptions of groundwater scarcity and their educational opportunities.

As a result, more than 90% of the students surveyed in both watersheds identified groundwater scarcity as a major issue. Around 95% reported that they are involved with housework aside from their studies. Usually, females are responsible for fetching drinking water, cooking, cleaning and taking care of their young siblings, while males helped with farming work. They associated directly their absenteeism from school to demand for home duties. In this sense, increasing groundwater scarcity is expected to intensify household chores, particularly on females to fetch water, who have to walk longer distances and spend more time executing this task. This may impact on inclusive educational opportunities for female students. Water scarcity was identified as being a primary factor influencing school attendance by 77% of female students who missed school.

What geoscientists can do?

Groundwater is a precious resource for communities, although optimising its potential can be difficult. Firstly, groundwater can not be found everywhere, which make drilling a risky business. Secondly, the quantity and quality of water that can be withdrawn in a borehole can vary just within a few meters.

Geoscientists can help by doing a good siting for a borehole, for example. This requires a professional with suitable training, experience of siting boreholes and knowledge of the best types of survey to carry out. This person can be a geologist, a hydrogeologist or an engineer with sufficient geoscience understanding. A consistent approach for well location involves identification of features on the ground that may be favourable for groundwater occurrence, selection of the most suitable geophysical method (if needed), data interpretation and stakeholder consultation. The dialogue with a community is important in terms of understanding where users would like boreholes to be. The (hydro)geologist need to point out contamination sources such as latrines, burial sites or other forms of pollution. They will also find out who owns the land and if it can be accessed by the community (read more). To know more about siting of drilled water wells, download this resource.

Borehole in Tanzania (Credit: Tumaini Fund)

Supply of clean water is fundamental for permitting women and girls to devote more time to the pursuit of education and income generation. Geoscience is fundamental to delivering SDG 6 (clean water) but also SDG 5 (gender equality).