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groundwater

Groundwater springs harbour hidden viruses

Groundwater springs harbour hidden viruses

In many parts of Sub-Saharan Africa, groundwater springs are a vital, precious source of water. They are also a reservoir of disease. Research presented at the European Geosciences Union General Assembly in Vienna reveals that groundwater reservoirs in Ghana, Tanzania and Uganda contain diverse communities of viruses – including those that present a risk to human health.

The work, carried out by IHE Delft in the Netherlands and a number of local universities, is the first to find such extensive virus communities in groundwater. Amongst the 25 virus families found were pox and herpes viruses, responsible for a number of skin infections. Papillomavirus, which causes several types of cancer, was also present in the water. And this is just a fraction of what’s likely to be out there – other methods are likely to reveal many more, scientists involved with the new research say.

According to the new findings, the reason for this plethora of pathogens is poor sanitation in areas where freshwater percolates down from the surface and recharges the groundwater supply. Here, the viruses persist for several years before being discharged at the surface.

The virus communities were identified by extracting DNA from the groundwater. This graphic shows how they enter the groundwater and the local population. Credit: IHE Delft

Better sanitation and safe water supplies are needed to address the issue, but there aren’t always enough resources to tackle both. In areas like Kampala (Uganda) as much as 60% of the population relies on groundwater as a source of water. Simply switching to another source is not an option – there are none available.

In Accra (Ghana) and Kampala – groundwater systems are quite confined, covering an area that closely matches the distribution of the community. This means you can use a local approach to groundwater management, and develop something that works well for the communities living there.

Hydrogeolologist Jan Willem Foppen and his team take time to learn from the community, identifying pathways for the future together – an approach called transition management. Each pathway leads to small interventions, that the team can learn from. “When you work with a community and co-create knowledge, you get beautiful and unexpected results,” says Foppen.

For Foppen, the enthusiasm of the local population towards this approach is one of the most rewarding parts of the job: “we see this being replicated in other communities in Ghana and in Kampala, that is the biggest compliment we can get.”

This is still much to uncover about these virus communities. For example, scientists don’t yet know whether the viruses are dead or alive. 70% of the DNA found in the springs was unidentifiable. What’s more there is a whole separate group of viruses – RNA viruses – that haven’t even been studied yet.

By Sara Mynott, EGU Press Assistant

Imaggeo on Mondays: Isolated atoll

Imaggeo on Mondays: Isolated atoll

Covering a total area of 298 km², the idylic natural atolls and reefs of the Maldives stretch across the Indian Ocean. The tropical nation is famous for it’s crystal clear waters and picture perfect white sand beaches, but how did the 26 ring-shaped atolls and over 1000 coral islands form?

Coral reefs commonly form immediately around an island, creating a fringe which projects seawards from the shore. If the island is of volcaninc origin and slowly subsides below sea level, while the coral continues to grow growing outwards and upwards, an atoll is formed. They are usually roughly circular in shape and have a central lagoon. If the coral reef grows high enough, it will emerge from the sea waters and start to form a  tiny island.

“I took this photo while flying over the Maldives, south of Malè, from a small seaplane,” describes Favaro, who took this stunning aerial image of an atoll above the Indian Ocean.

Pictured, goes on to explain Favaro,

“[is] part of the ring-shaped coral reef bounding the atoll. On the right side of the image there is the lagoon and on the left side the open ocean. The coral reef is interrupted twice by ‘Kandu’ (water passages in Dhivehi [the language spoken in the Maldives]), which are the places where water flows in and out of the atoll when the tides changes”.

Two small harbours and antennas suggest the two small islands are occupied by local people, not by a resort or hotels.

“What always strikes me is how they can live so isolated, in a place which doesn’t offer basic resources, such as drinkable water,” says Favaro.

Fresh water is scarce in this archipelago nation. Rainwater harvesting is unreliable; poor rainfall means depleted collection tanks and groundwater tables. The problem is being exacerbated by climate change which is altering the monsoon cycle and rainfall patters over the Indian Ocean. As a result, the country relies heavily on desalination plants (and imported bottled water) to sustain the nation and the 1 million tourists who visit annually.

This animation shows the dynamic process of how a coral atoll forms. Corals (represented in tan and purple) begin to settle and grow around an oceanic island forming a fringing reef. It can take as long as 10,000 years for a fringing reef to form. Over the next 100,000 years, if conditions are favorable, the reef will continue to expand. As the reef expands, the interior island usually begins to subside and the fringing reef turns into a barrier reef. When the island completely subsides beneath the water leaving a ring of growing coral with an open lagoon in its center, it is called an atoll. The process of atoll formation may take as long as 30,000,000 years to occur. Caption and figure credit: National Oceanographic and Atmospheric Administration (NOAA).

References and further reading

How Do Coral Reefs Form? An educational resource by NOAA

Amazing atolls of the Maldives – a feature on NASA’s Earth Observatory.

 

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/.

 

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 http://imaggeo.egu.eu/upload/.

Imaggeo on Mondays: Tombstones Mountains

Imaggeo on Mondays: Tombstones Mountains

This week’s Imaggeo image is brought to you by one of our network bloggers, Matt Herod. Of the image, Matt said ” this particular one is one of my all time favourites. I have even blown it up and hung it on my wall at home,” and we couldn’t agree more; this Canadian landscape is breathtaking. Dive into this post and let Matt take you on a tour of the hydrology, archaeology and volcanic history of the Tombstone Mountain Range.

The Yukon Territory in the fall is a wonderful place and may be among the most beautiful on Earth. As the days shorten the colours become more vibrant and the grasses and shrubs transform. Combine this with the stark and rugged nature of the landscape and you have a potent combination that begs to be explored and photographed.

The subject of this photo is the Tombstone Mountain Range just north of Dawson City, a world heritage site famous for its gold rush, the Sourtoe Cocktail and the funnest casino I have ever been to. The Tombstones constitute the headwaters of the North Klondike River which flows at the base of the valley in the photo and eventually meets up with the larger Klondike River and then joins with the Yukon River at Dawson. Hydrologically the Tombstones mark a continental divide and the transition from southern flowing rivers to northern ones takes place nearby as the many of the rivers just slightly to the north feed into the Peel River and eventually the mighty Mackenzie. A colleague of mine recently concluded a project on the North Klondike measuring the groundwater discharge and chemistry of the river over several years to understand the water sources and the effect of permafrost on the local hydrology.

Indeed, at the base of the valley there is a groundwater discharge point that builds up every winter into a large, layered sheet of ice called and aufeis. As the warmer groundwater continues to discharge throughout the winter it freezes when it meets the cold air forming the aufeis. These structures are often seen at groundwater discharge points in the far north.

The Tombstones themselves, named after the really pointy mountain in the background, are geologically very interesting. Indeed, this relief was created by igneous intrusions during the Cretaceous period. More recently, alpine glaciations shaped the terrain giving rise to a suite of interesting geomorphological and permafrost structures.

The region also has a fascinating archeological heritage and is home to over 70 sites dating back ~8000 years to the Holocene period and some of the earliest human incursions into North America via the Bering land bridge.

This photo was taken in August 2012 on my way up the Dempster Highway. I was collecting water samples for iodine-129 analysis and stopped off in the Tombstone Territorial Park for a sample.

By Matt Herod, researcher at Department of Earth Sciences at the University of Ottawa in Ontario, Canada.

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/.