Taxonomy term

lucas joel

What drives hot spots of sea-level rise?

As sea levels creep up around the world, scientists have observed hot spots where regional rates of sea-level rise greatly outpace the global average. But what drives the formation of these hot spots, and how long they last, have been mysteries. In a new study, scientists tracking sea levels along the Florida coast suggest that the combined effects of two naturally occurring climate processes, the El Niño-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO), control sea-level hot spot formation along the U.S. East Coast.

01 Dec 2017

Chemical clues illuminate fossil plant relationships

To reconstruct relationships among extinct plants and animals, paleontologists often compare genetic sequences from distinct organisms or analyze differences in fossil shapes. But both techniques have limitations: DNA does not last more than about a million years in the rock record, so genetic comparisons are typically limited to relatively recent species; and finding fossils intact enough to use for shape comparisons can be difficult. In a recent study, scientists describe a new technique that could help get around these issues — for some plants at least — using molecular remnants that are more robust than DNA and are preserved in fossil leaves.

17 Oct 2017

Volcanism triggered end-Triassic extinction

The end-Triassic mass extinction exterminated up to three-quarters of all species on land and in the oceans 201 million years ago. This die-off opened up ecological niches and allowed for, among other changes, dinosaurs to diversify and spread across terrestrial ecosystems during the rest of the Mesozoic. Volcanism has long been implicated in the extinction, but whether it had a major impact on the planet at the time has remained unclear. In new research, scientists observed elevated mercury concentrations in extinction-aged rocks from around the world. Because volcanism is the main nonanthropogenic source of mercury in the environment, the findings suggest that volcanic activity was likely the main extinction trigger at the end of the Triassic.

21 Sep 2017

Dust influences pollution levels in eastern China

Air pollution often enshrouds cities in eastern China in a thick haze that impairs visibility and causes respiratory health problems. Emissions from human activity are mainly to blame, but climate researchers now report that natural forces — namely, dust kicked into the air by wind — can also exert a strong control over how much pollution persists in the air.

22 Aug 2017

New global volcanic emissions map debuts

Volcanoes may not always be erupting ash or lava, but that doesn’t mean they’re not venting other materials. Many, in fact, continuously spew gases like carbon dioxide and sulfur dioxide into the air. In a new study, volcanologists compiled data tracking such releases, collected by NASA’s Aura satellite, into the first global map of volcanic sulfur dioxide emissions.

13 Jul 2017

Precambrian rumblings of the Cambrian Explosion

The Cambrian Explosion, when the ancestors of most of today’s animal groups began appearing in the fossil record about 542 million years ago, was — as the name suggests — a geologically abrupt event. Paleontologists have long thought of the event as marking a boundary between distinct Precambrian and Cambrian faunas. In new research published in Geology, however, scientists report that small, shelly fossils once thought to occur only in Cambrian rocks have been found in rocks dating to the late Ediacaran, just before the Cambrian, implying an earlier start to the explosion than previously thought.

11 Jul 2017

New cloud types recognized

Familiar clouds like cumulonimbus, cirrocumulus and nimbostratus have some new company. The World Meteorological Organization (WMO) has published a new edition of its International Cloud Atlas, the first revision since 1987. The updated version — released in digital format for the first time — compiles recent observations and introduces about a dozen new terms, such as “asperitas,” which refers to a cloud whose sweeping undulations resemble the surface of a stormy sea, as well as names for clouds induced by wildfires and by human activity. There is even a new cloud species, “volutus,” which describes long, tube-shaped rolling clouds.

27 Jun 2017

Two ichthyosaurs become one

While dinosaurs ruled on land in the Mesozoic, dolphin-like marine reptiles called ichthyosaurs roamed the oceans. Paleontologists first described the genus in 1821 based on remains discovered in England, naming the first species Ichthyosaurus communis. The description of a second species, I. intermedius, followed in 1822. Although these two species were the earliest-known ichthyosaurs, they are also some of the most poorly understood, as their initial descriptions were based on limited remains.

22 Jun 2017

Whirling "gravel devils" show wind can carry more than just sand

Sand grains, by definition, are between 0.06 and 2 millimeters in diameter, and they are often thought of by scientists as the largest sediments that wind can transport, with larger sediments simply being too hefty for winds to keep aloft. But strong winds, particularly in tropical storms and tornadoes, are known to move objects far larger than sand over short distances. Now, in the high Andes of Chile on the Salar Gorbea salt flat, evidence has been found of tornadic “gravel devils” whipping across the landscape and transporting gypsum crystals as long as 27 centimeters.

16 Jun 2017

Lucy liked hanging out in trees

Lucy, the 3.2-million-year-old human ancestor discovered in Ethiopia in 1974, is one of the most complete early hominin skeletons ever found. Still, despite the skeleton’s completeness, debate continues about how Lucy got around: Did she spend most of her time walking on the ground or climbing in trees? In a new study, scientists studying Lucy’s upper limb bones have found that she likely spent more time in trees — and was a more capable climber — than later hominin species like Homo erectus and Homo sapiens.

13 Apr 2017