New research investigating the transition of the Sahara from a lush, green landscape 10,000 years ago to the arid conditions found today, suggests that humans may have played an active role in its desertification. 

The desertification of the Sahara has long been a target for scientists trying to understand climate and ecological tipping points. A new paper published in Frontiers in Earth Science by archeologist Dr. David Wright, from Seoul National University, challenges the conclusions of most studies done to date that point to changes in the Earth's orbit or natural changes in vegetation as the major driving forces.

It has long been suspected that spiders are one of the most important groups of predators of insects. Zoologists at the University of Basel and Lund University in Sweden have now shown just how true this is – spiders kill astronomical numbers of insects on a global scale. The scientific journal The Science of Nature has published the results.

A new study from a Coastal Waters Consortium team of researchers led by Rutgers University postdoctoral researcher, Michael McCann, has found which birds, fish, insects and other animals affected by the Deepwater Horizon explosion should be given top priority for conservation, protection and research.

Researchers from Stanford and the University of Calgary have transformed pulses of electrical current sent 1,000 feet underground into a picture of where seawater has infiltrated freshwater aquifers along the Monterey Bay coastline.

The findings, which will be published in an upcoming issue of the Journal of Hydrology but are available online now, help explain factors controlling this phenomenon, called saltwater intrusion, and could help improve the groundwater models that local water managers use to make decisions about pumping groundwater to meet drinking or farming needs.

As climate change continues to impact the Antarctic, glacier melt and permafrost thaw are likely to make more liquid water available to soil and aquatic ecosystems in the McMurdo Dry Valleys, potentially providing a more nutrient-rich environment for life, according to a Dartmouth study recently published in Antarctic Science. (A pdf of the study is available upon request).

With an average annual air temperature of -2.2 F and an average precipitation of 3-50 mm per year, the McMurdo Dry Valleys of Antarctica are dominated by dry soils underlain by permafrost. The Dry Valleys ecosystem is severely limited by liquid water and nutrients, resulting in limited organic matter. One such limited nutrient is phosphorus, an element that is essential to all living organisms. Understanding the spatial distribution of phosphorus in the soil is crucial to identifying where life could become more abundant in the future. 

Logging that happens today and potential future rainfall reductions in the Amazon could push the region into a vicious dieback circle. If dry seasons intensify with human-caused climate change, the risk for self-amplified forest loss would increase even more, an international team of scientists finds. If however there is a great variety of tree species in a forest patch, according to the study this can significantly strengthen the chance of survival. To detect such non-linear behavior, the researchers apply a novel complex network analysis of water fluxes.

“The Amazon rainforest is one of the tipping elements in the Earth system,” says lead-author Delphine Clara Zemp who conducted the study at the Potsdam Institute for Climate Impact Research, Germany. “We already know that on the one hand, reduced rainfall increases the risk of forest dieback, and on the other hand, forest loss can intensify regional droughts. So more droughts can lead to less forest leading to more droughts and so on. Yet the consequences of this feedback between the plants on the ground and the atmosphere above them so far was not clear. Our study provides new insight into this issue, highlighting the risk of self-amplifying forest loss which comes on top of the forest loss directly caused by the rainfall reduction.” This study results from the  German-Brazilian Research Training Group on Dynamical Phenomena in Complex Networks at (IRTG1740) hosted by Humboldt Universität zu Berlin. 

Conservationists working to safeguard tropical forests often assume that old growth forests containing great stores of carbon also hold high biodiversity, but a new study finds that the relationship may not be as strong as once thought, according to a group of researchers with contributions from WCS (Wildlife Conservation Society) and other organizations.

 Tropical forests are exceptionally rich in both carbon and biodiversity, but the study recently published in the journal Scientific Reports indicates that, within the tropics, tree diversity and forest carbon do not necessarily correlate, and that there is no detectable relationship between the two factors across a region, a scale relevant for conservation planning and the establishment of protected areas. For instance, in Central Africa, some areas that are dominated by one or a few tree species are high in carbon density, whereas some forests with many more tree species have a lower carbon density. 

Ocean acidification is spreading rapidly in the western Arctic Ocean in both area and depth, potentially affecting shellfish, other marine species in the food web, and communities that depend on these resources, according to new research published in Nature Climate Change by NOAA, Chinese marine scientists and other partners.

Scientists have long suspected that ice caps formed repeatedly in the tropical Andes during the late Pliocene, but only evidence of a single glaciation was known until now.

Stanford marine biologists have discovered that corals activate a specific group of ancient, defensive genes when exposed to stressful environmental conditions. These stress-induced genes could serve as a kind of warning sign for coral bleaching events.

In the study, researchers monitored three coral colonies in a lagoon on Ofu Island, American Samoa, for their response to stressors like high temperatures, oxygen, and ocean acidity. On the hottest days, the researchers saw a significant change in which genes the corals were activating within their cells. See video here.