#salinization

Both the seashore and the desert are water-short environments, and it is hardly surprising that they converge to a common picture of powdery sand, date palm, bare rock and scraggly scrub.The saline spray and mist coming in from the ocean so salinizes the environment of the littoral that whatever fresh water comes in here in the form of sporadic rain, or stream wash is rendered unusable by plant and animal life, favoring thus xerophytic vegetation and reptiles. A photo virtually identical to the above photo could just as easily have been taken in any part of the desiccated Middle East.

North America's freshwater lakes are getting saltier, study finds

North America's freshwater lakes are getting saltier due to development and exposure to road salt. A study of 371 lakes published today in the Proceedings of the National Academy of Sciences reports that many Midwestern and Northeastern lakes are experiencing increasing chloride trends, with some 44% of lakes sampled in these regions undergoing long-term salinization.                                

The study is the first large-scale analysis of chloride trends in freshwater lakes. It was conducted by a team of fifteen researchers as part of the Global Lake Ecological Observatory Network (GLEON) Fellowship Program, an initiative that seeks to train the next generation of freshwater scientists and practitioners.

Lead author Hilary Dugan, a limnologist at the University of Wisconsin-Madison and former Cary Institute of Ecosystem Studies Postdoctoral Fellow, explains, "We compiled long-term data, and compared chloride concentrations in North American lakes and reservoirs to climate and land use patterns, with the goal of revealing whether, how, and why salinization is changing across broad geographic scales. The picture is sobering. For lakes, small amounts of shoreline development translate into big salinization risks."

Salting our freshwater lakes, Proceedings of the National Academy of Sciences (2017). www.pnas.org/cgi/doi/10.1073/pnas.1620211114

Excerpt from this story from Grist:

Eerily empty, abandoned fields stretch across the coast of the southeast United States, replacing once sprawling fields of golden wheat, corn, and soybeans. 

For centuries, farmers have favored the rich soil of coastal areas during the growing season. “It’s very fertile soil, especially in some areas that are called the ‘black lands.’ These are really deep organic soils that formed on the coast over millennia,” says Michael Gavazzi, coordinator of the USDA Southeast Climate Hub coordinator and natural resource specialist. 

It’s a different story when the floods come in. Hurricanes and tropical storms bring torrential rain and powerful winds that cause storm surges—abnormally large waves that can tower up to 25 feet in height. The aftermath of such disasters is devastating. Crop damage and equipment loss can rack up to thousands of dollars for farmers, even with insurance. The spread of invasive species hinders future growing seasons of certain crops. And most of all, flooding risks long-term consequences to soil health and the geological makeup of farms that could force farmers to permanently abandon their land. 

“Fresh water [non-saline] flooding from intense rainfall events can [have] short- and long-term consequences,” says Gavazzi, “but the land will usually recover.” However, ocean-driven storm surge flooding is saltwater, and crop productivity can be negatively impacted. Repeated flooding can permanently reduce forest, range, and agricultural production of these coastal areas. 

Breakthrough in food security with Dutch knowledge of saline agriculture

  MARC. | ZILT PROEFBEDRIJF 

    Breakthrough in food security with Dutch knowledge of saline agriculture

Dutch scientists have found a method for growing certain crops on salinized, non-arable farmland. This is truly an innovation, since food production on salinized soil has always been considered impossible. It was discovered that specific varieties of potatoes, carrots, red onions, white…

Salinisation of Rivers

With often devastating environmental impacts and high economic costs, the salinisation of rivers is a problem that is beginning to affect all of us, no matter what country we live in. Global climate change (be it natural or anthropogenicaly forced) and increasing demands for fresh water are making the issue we face worse.

Of course, river salinity can be natural. The geology of the area where a river flows may contain salt minerals such as gypsum or halite that are preferentially and easily dissolved by flowing water, or by the climate. However an increasingly large amount of the salinity in our river systems is coming from anthropogenic forces; industrial and agricultural activity, mining, and waste discharge from domestic sites.

In all of the Earth’s river systems, the additional salinity from man-made situations is threatening not just the ecosystems in the natural world that depend on the rivers for survival, but ultimately also the human race, who at the end of the scale depend on the rivers for drinking water. The additional salinity caused by our own doing is giving us an economic headache, as well as being a threat to the health of the public. Many of the chemicals used to make saline water drinkable are harmful to human health, as well as being poisonous to many plants and animals; this affects the long term food-web.

The worst cases of salinisation come from Australian rivers, and as yet there is an unclear reason why. It does however appear that local groundwater systems respond rapidly to the recharge of water, taking perhaps 30-50 years to dispel highly saline water after the clearing of ground for agricultural reasons. In Australia however there is a great collaborative effort between both the scientists and the local farmers to try to discover exactly what is happening, as well as why and what can be done to prevent the disruption of what is obviously a fragile balance. Europe also faces the same problem, with Spain being one of the worst hit countries- the land is arid, but the water sources have been over exploited by the people, and high salinity is the result.

So what can we do about it?

Well in Europe at least until new legislation is introduced, not a lot. Salinity is not a factor that has tight environmental controls, meaning there is no universal “safe” level of salinity, and until legislation comes into place it can be difficult to set boundaries for the mining and agricultural industry. There is also a public awareness issue. Many people do not understand how excess salinity can be detrimental to the fragile ecosystems that rely on the worlds river systems.

There is some good news though. There has been a successful salinity management programme: the Hunter River in New South Wales, Australia. The programme is called Hunter River Salinity Trading Scheme, and in simple terms works by discharging water into areas that are low saline-high fresh water, and by not discharging any water where there is low flow along the river. To read fully how the scheme works head here: http://bit.ly/XHBSzI.

In the future, with an uncertain climate, the issue is likely to get worse. In order to tackle the issue the leaders of the world must come together to introduce legislation to control and try to reverse the issue before it becomes too late.

Much more information can be found in the links below.

-LL

http://www.sciencedaily.com/releases/2013/01/130111092529.htm

http://www.sci.sdsu.edu/salton/TheSalinityofRivers.html

http://www.countercurrents.org/cc150113A.htm

http://sites.nicholas.duke.edu/avnervengosh/files/2011/08/Salinization.pdf

http://www.acarp.com.au/abstracts.aspx?repId=C11050

http://www.ub.edu/web/ub/en/menu_eines/noticies/2013/01/004.html

http://www.anra.gov.au/topics/salinity/groundwater-flow/index.html

http://www.csiro.au/files/files/pmyj.pdf

Irrigation makes it possible to grow crops in regions where there is too little rainfall to meet the plants’ water needs. But applying too much water can lead to salinization. That’s because irrigated water contains dissolved salts that are left behind when water evaporates. Over time, concentrations of those salts can reach levels that make it more difficult for plants to take up water from the soil. Higher concentrations may become toxic, killing the crops.

Qadir and his colleagues estimated the cost of crop losses from salinization by reviewing more than 20 studies from Australia, India, Pakistan, Spain, Central Asia and the United States, published over the last two decades. They found that about 7.7 square miles of land in arid and semi-arid parts of the world is lost to salinization every day. Today some 240,000 square miles—an area about the size of France—have become degraded by salt. In some areas, salinization can affect half or more of irrigated farm fields.