An Analog for Martian Aeolian Ridges Found in Iran's Lut Desert

Mega-ripples in Iran: A new analog for transverse aeolian ridges on Mars

Authors:

Foroutan et al

Abstract:

A new terrestrial analog site for transverse aeolian ridges (TARs) is described in this study. The Lut desert of Iran hosts large ripple-like aeolian bedforms, with the same horizontal length scales and patterns of TARs on Mars. Different classes of TARs and different types of other aeolian features such as sand dunes, zibars, dust devil tracks and yardangs can be found in this area, which signify an active aeolian region. This area represents a unique site to study the formation and evolution of these enigmatic features, with potential relevance toward a better understanding of TARs on Mars.

Increasing Aridity Negatively Impacts Soil Microbes in Global Drylands

Increasing aridity reduces soil microbial diversity and abundance in global drylands

Authors:

Maestre et al

Abstract:

Soil bacteria and fungi play key roles in the functioning of terrestrial ecosystems, yet our understanding of their responses to climate change lags significantly behind that of other organisms. This gap in our understanding is particularly true for drylands, which occupy ∼41% of Earth´s surface, because no global, systematic assessments of the joint diversity of soil bacteria and fungi have been conducted in these environments to date. Here we present results from a study conducted across 80 dryland sites from all continents, except Antarctica, to assess how changes in aridity affect the composition, abundance, and diversity of soil bacteria and fungi. The diversity and abundance of soil bacteria and fungi was reduced as aridity increased. These results were largely driven by the negative impacts of aridity on soil organic carbon content, which positively affected the abundance and diversity of both bacteria and fungi. Aridity promoted shifts in the composition of soil bacteria, with increases in the relative abundance of Chloroflexi and α-Proteobacteria and decreases in Acidobacteria and Verrucomicrobia. Contrary to what has been reported by previous continental and global-scale studies, soil pH was not a major driver of bacterial diversity, and fungal communities were dominated by Ascomycota. Our results fill a critical gap in our understanding of soil microbial communities in terrestrial ecosystems. They suggest that changes in aridity, such as those predicted by climate-change models, may reduce microbial abundance and diversity, a response that will likely impact the provision of key ecosystem services by global drylands.

Mars Circa 3015?

Looks like it, but, no, its the Namib Desert.  img src.

How Arid Biomes React to Climate Change

Approximately 40 percent of the earth's surface is covered by drylands in which average annual precipitation is lower than evaporation. The changes projected to unfold in these areas in the course of climate change are alarming. Greater variations in annual and seasonal precipitation will lead to more frequent droughts and, presumably, longer drought periods. This means that drylands are among those areas most severely affected by climate change.

Research has thus far not adequately addressed the question of how strongly annual plant growth in pasture landscapes - hence the available food for livestock - is affected by droughts. Also, how predictable is the correlation? Yet this knowledge about vegetation stability would be essential for more accurate predictions of the effects of climate change in these areas. Over the past years, Dr. Jan Ruppert, an ecologist from the University of Cologne, has compiled hundreds of long-term studies on annual plant growth in drylands. Together with Dr. Anja Linstädter, the head of his working group at the University of Cologne, he has now completed his analysis of these data. The researchers are looking for an answer to the question of how droughts of varying intensity affect plant production - during and after the event. They are particularly interested in whether or not certain characteristics of the vegetation or the grazing regime affect the outcome. In this context, the scientists differentiate between two aspects of stability: on the one hand, the vegetation's durability to droughts of varying intensity (resistance), and on the other hand its ability to regenerate after a drought (recovery).

"We were surprised to see that the type of ecosystem (biome) is a rather poor indicator of vegetation stability in the face of drought. It does not make a large difference whether a drought occurs in a savanna, grassland or shrubland. The decisive factor is the dominant herbaceous life history - that is, whether we are dealing with annual or perennial plants", Ruppert explains. Drylands that are dominated by annual plants are more severely affected during droughts, but recover more quickly afterwards. Areas in which perennial plants dominate exhibit the opposite trend. The effect of the grazing regime on vegetation stability in the face of drought is also highly dependent on whether one is dealing with annual or perennial plants. Enduring communities of plants will react to grazing with a lower drought resistance. Grazing does not, however, have a significant effect on resistance in areas where annual plants dominate. "Our results indicate that the vegetation of drylands is not capable of optimizing its resistance and recovery potential at the same time," Linstädter concludes.

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Deserts are Major Drivers in the Carbon Cycle

Dryland ecosystems, which include deserts to dry-shrublands, play a more important role in the global carbon cycle than previously thought. In fact, they have emerged as one of its drivers, says Montana State University faculty member Ben Poulter.

Surprised by the discovery, Poulter and his collaborators explained their findings in Nature. At the same time, they urged global ecologists to include the emerging role of dryland ecosystems in their research. Nature is a weekly international journal that publishes peer-reviewed research in all fields of science and technology.

"Our study found that natural events in Australia were largely responsible for this anomaly," Poulter said. "La Nina-driven rainfall during 2010 and 2011, as well as the 30-year greening up of its deserts and other drylands contributed to significant changes across the globe."

Poulter, who has a dual appointment in MSU's Department of Ecology and the Institute on Ecosystems, came to MSU in January. Before that, he worked in France at the Laboratoire des Sciences du Climat et de l'Envionnement (LSCE) where he contributed to compiling information for the Global Carbon Project's annual global carbon budget assessment.

He realized during that process that the world's land carbon sink in 2011 seemed to be absorbing an unusually large amount of carbon, Poulter said. Carbon dioxide moves constantly between land, oceans, vegetation and the atmosphere. When one of those absorbs more carbon dioxide than it releases, it's referred to as a carbon sink.

Poulter and his collaborators investigated the phenomena with a variety of data sets and modeling approaches. They eventually discovered surprising interactions between climate extremes and desert greening that increased in importance over the past 30 years. Further study showed that the dryland systems in the Southern Hemisphere, specifically Australia, had particularly high productivity in response to increased La Nina-phase rainfall.

"What surprised us was that no analogous biosphere response to similar climatic extremes existed in the past 30 years, prompting us to explore whether documented dryland-greening trends were responsible for changes in the carbon cycle dynamics," said Philippe Ciais, co-author and senior scientist at LSCE.

The authors discovered that an increase in the precipitation sensitivity of a range of ecosystems processes occurred between the periods of 1982-1996 and 1997-2011. One of those processes was the greening of desert vegetation. Together those processes led to a four-fold increase in net carbon uptake to precipitation over the past 30 years.

"Novel responses of the biosphere have been predicted to occur following human activities that have caused unprecedented changes in atmospheric carbon dioxide concentrations, climate and land cover," Poulter continued. "Our study provides new evidence that interactions among these human activities are now also impacting dryland biomes. These findings have global implications that should be considered in monitoring networks and earth system models."

The large 2011 land carbon uptake is not expected to lead to long-term increases in ecosystem carbon accumulation, according to the researchers.

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Sahara Forest Project's Qatar Pilot Project Appears to be Successful

A project to “green” desert areas with an innovative mix of technologies—producing food, biofuel, clean water, energy, and salt—reached a milestone this week in the Gulf state of Qatar. A pilot plant built by the Sahara Forest Project (SFP) produced 75 kilograms of vegetables per square meter in three crops annually, comparable to commercial farms in Europe, while consuming only sunlight and seawater. The heart of the SFP concept is a specially designed greenhouse. At one end, salt water is trickled over a gridlike curtain so that the prevailing wind blows the resulting cool, moist air over the plants inside. This cooling effect allowed the Qatar facility to grow three crops per year, even in the scorching summer. At the other end of the greenhouse is a network of pipes with cold seawater running through them. Some of the moisture in the air condenses on the pipes and is collected, providing a source of fresh water.

One of the surprising side effects of such a seawater greenhouse, seen during early experiments, is that cool moist air leaking out of it encourages other plants to grow spontaneously outside. The Qatar plant took advantage of that effect to grow crops around the greenhouse, including barley and salad rocket (arugula), as well as useful desert plants. The pilot plant accentuated this exterior cooling with more “evaporative hedges” that reduced air temperatures by up to 10°C. “It was surprising how little encouragement the external crops needed,” says SFP chief Joakim Hauge.

The third key element of the SFP facility is a concentrated solar power plant. This uses mirrors in the shape of a parabolic trough to heat a fluid flowing through a pipe at its focus. The heated fluid then boils water, and the steam drives a turbine to generate power. Hence, the plant has electricity to run its control systems and pumps and can use any excess to desalinate water for irrigating the plants.

The Qatar plant has also experimented with other possibilities such as culturing heat-tolerant algae, growing salt-tolerant grasses for fodder or biofuel, and evaporating the concentrated saline the plant emits to produce salt.

The Qatar plant—which is supported by Qatari fertilizer companies Yara International and Qafco—is just 1 hectare in extent with 600 square meters of growing area in the greenhouse. The fact that this small greenhouse produced such good yields, Hauge says, suggests that a commercial plant—with possibly four crops a year—could do even better. SFP researchers estimate that a facility with 60 hectares of growing area under greenhouses could provide all the cucumbers, tomatoes, peppers, and egglants now imported into Qatar. The results “reveal the potential for enabling restorative growth and value creation in arid land,” Hauge says. "I personally think that it is very important that people promote and invest in these ideas. Protected agriculture (I call it "indoor food production") is an important option for the desert areas, particularly in the Middle East," says Richard Tutwiler, director of the Desert Development Center at the American University in Cairo. "The big question is economic feasibility. How much did it cost to produce 75 kg of cucumbers per square meter?"

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Flash Flooding in Page, AZ...YESTERDAY

We went through there on the 7th of July.  Whoa.

Using Bacteria to Make Africa's Great Green Wall

Oy! Not the Best Use of Water Resources!

In Saudi Arabia...

In the UAE....

In China...

In the USA...

oy.