Think of the Sahara and you will conjure images of a vast desert landscape, with nothing but sand as far as the eye can see. But for a period of about 10,000 years, the Sahara was characterized by lush, green vegetation and a network of lakes, rivers and deltas. (more…)
All living organisms rely on iron as an essential nutrient. In the ocean, iron’s abundance or scarcity means all the difference as it fuels the growth of plankton, the base of the ocean’s food web.
A new study by biogeochemists and glaciologists at Woods Hole Oceanographic Institution (WHOI) identifies a unexpectedly large source of iron to the North Atlantic – meltwater from glaciers and ice sheets, which may stimulate plankton growth during spring and summer. This source is likely to increase as melting of the Greenland ice sheet escalates under a warming climate. (more…)
Jaisi laboratory tracks chemicals in water, farmland throughout Mid-Atlantic
University of Delaware researcher Deb Jaisi is using his newly established stable isotope facility in the Environmental Biogeochemistry Laboratory (EBL) to find the fingerprints of isotopes in chemical elements — specifically phosphorus — in order to track sources of nutrients in the environmentally-sensitive Chesapeake Bay, other bodies of water and farmland throughout the Mid-Atlantic.
Jaisi, assistant professor in the Department of Plant and Soil Sciences in the College of Agriculture and Natural Resources, explained that he and his research team are currently working on many projects in the EBL, including two that are funded through seed grants, one focusing on terrestrial phosphorus sources and the other on marine phosphorus sources in the Chesapeake. One of those grants is from the UD Research Foundation (UDRF) and is titled “Role of Non-terrestrial Phosphorus Sources in Eutrophication in the Chesapeake Bay.” (more…)
Antarctica’s topography began changing from flat to fjord-filled starting about 34 million years ago, according to a new report from a University of Arizona-led team of geoscientists.
Knowing when Antarctica’s topography started shifting from a flat landscape to one with glaciers, fjords and mountains is important for modeling how the Antarctic ice sheet affects global climate and sea-level rise. (more…)
Better science communication could lead to a more informed American public.
Public acceptance of climate change’s reality may have been influenced by the rate at which words moved from scientific journals into the mainstream, according to anthropologist Michael O’Brien, dean of the College of Arts and Science at the University of Missouri. A recent study of word usage in popular literature by O’Brien and his colleagues documented how the usage of certain words related to climate change has risen and fallen over the past two centuries. Understanding how word usage affects public acceptance of science could lead to better science communication and a more informed public.
“Scientists can learn from this study that the general public shouldn’t be expected to understand technical terms or be convinced by journal papers written in technical jargon,” O’Brien said. “Journalists must explain scientific terms in ways people can understand and thereby ease the movement of those terms into general speech. That can be a slow process. Several words related to climate change diffused into the popular vocabulary over a 30-50 year timeline.” (more…)
A new study combining the latest archaeological evidence with state-of-the-art geoscience technologies provides evidence that climate change was a key ingredient in the collapse of the great Indus or Harappan Civilization almost 4000 years ago. The study also resolves a long-standing debate over the source and fate of the Sarasvati, the sacred river of Hindu mythology.
Once extending more than 1 million square kilometers across the plains of the Indus River from the Arabian Sea to the Ganges, over what is now Pakistan, northwest India and eastern Afghanistan, the Indus civilization was the largest—but least known—of the first great urban cultures that also included Egypt and Mesopotamia. Like their contemporaries, the Harappans, named for one of their largest cities, lived next to rivers owing their livelihoods to the fertility of annually watered lands. (more…)
A Woods Hole Oceanographic Institution (WHOI) scientist, analyzing ancient plankton DNA signatures in sediments of the Black Sea, has found for the first time that the same genetic populations of a virus and its algal host can persist and coexist for centuries. The findings have implications for the ecological significance of viruses in shaping algae ecosystems in the ocean, and perhaps fresh water as well.
“The finding that the DNA of viruses and algal host cells can be preserved in the geological records is of great interest to microbial ecologists,” said Marco Coolen of WHOI’s Marine Chemistry and Geochemistry department and author of the study, which appears in the July 22 issue of Science. “This offers unprecedented insights into long-term algal, viral, and host population dynamics between globally important algae and their viral pathogens in the ocean.” (more…)
AUSTIN, Texas — An international team of geoscientists has discovered an unusual geological formation that helps explain how an undersea earthquake off the coast of Sumatra in December 2004 spawned the deadliest tsunami in recorded history.
Instead of the usual weak, loose sediments typically found above the type of geologic fault that caused the earthquake, the team found a thick plateau of hard, compacted sediments. Once the fault snapped, the rupture was able to spread from tens of kilometers below the seafloor to just a few kilometers below the seafloor, much farther than weak sediments would have permitted. The extra distance allowed it to move a larger column of seawater above it, unleashing much larger tsunami waves. (more…)
