Thousands of abandoned coal mines in Pennsylvania have left a legacy: Mine drainage with sky-high metal concentrations is polluting Pennsylvania’s streams and groundwater.

Edward Drinker Cope and his archrival, Othniel Charles Marsh, waged one of the most famous feuds in paleontology in the late 19th century, risking scientific integrity and financial well-being in a race to discover the most new fossils.

A cluster of 1.5-million-year-old footprints found in the Great Rift Valley show that these early hominins walked with a modern gait: big toe angled forward rather than splayed to the side, and a high, not flat, arch.

With global energy demand rising and fossil fuel supplies increasingly politicized and insecure, the biofuels genie is out of the bottle and here to stay. Now it is just a question of how fast — and in what ways — the industry will grow.

Agricultural development has had a profound impact on the water quality of the Everglades. The problems extend beyond phosphorus in fertilizers, however: sulfate, mercury and other contaminants are also threatening the health of the wetlands. To restore them to their former glory, scientists and policymakers need to come up with a comprehensive new plan.

Long after life first emerged from sea onto land, the early ancestors of whales began to reconsider the ocean. How these amphibious whales evolved to return to their aquatic habitat has long been a mystery — but some fascinating new fossils may help explain this transition. 

As Central America’s most popular tourist destination, Costa Rica draws millions of visitors each year. And beneath the rich veneer of life inhabiting one of Costa Rica’s more remote and undeveloped areas, the Osa Peninsula, the local geology is also quite stunning.

Unassuming algae could be the ultimate in “green” fuel, powering everything from cars to jets. But if it's going to compete with oil and gas, algae can't stay in the backyard — commercialization will require investment in molecular genetics research, algal physiology and engineering.

Two hundred years after Charles Darwin was born, studies are showing that there is much more to evolution than just random variation followed by selection of the fittest. DNA isn't the only inheritable molecular info: Genomic settings that can turn a gene on or off — sometimes triggered by stress or diet — may also be passed down from generation to generation.

Earthworms play a major role in soil ecology — and, as Darwin discovered, many of them also leave crystals of calcite behind as they churn through the soil. But why they do it is still a mystery.

Last year, Congress asked the Department of Energy to store spent nuclear fuel from decommissioned reactors at a temporary facility. But in December, DOE said it lacks the authority to do that.

Many things have been stolen from London's Natural History Museum over the past five years — but none, perhaps, odder than this.

The size of raindrops or hailstones inside a powerful supercell thunderstorm is a factor in whether a tornado will form.

The National Academy of Sciences launched an initiative late last year to promote collaboration between the scientific community and Hollywood. The collaboration may change the way Hollywood portrays science and scientists — and maybe change how the public views science.