At just over 14 million square kilometres, the Arctic Ocean is the smallest and shallowest of the world’s oceans. It is also the coldest. An expansive raft of sea ice floats near its centre, expanding in the long, cold, dark winter, and contracting in the summer, as the Sun climbs higher in the sky. Every […]
Authors: Ceridwen Fraser, Associate professor, University of Otago; Christina Hulbe, Professor and Dean of the School of Surveying (glaciology specialisation), University of Otago; Craig Stevens, Associate Professor in Ocean Physics, National Institute of Water and Atmospheric Research, and Huw Griffiths, Marine Biogeographer, British Antarctic Survey In 2018, a map named after an oceanographer went viral […]
Isabel Hofmeyr, University of the Witwatersrand and Charne Lavery, University of Pretoria On many beaches around the Indian Ocean, keen observers may spot bits of broken pottery. Washed smooth by the ocean, these shards are in all likelihood hundreds of years old, from centres of ceramic production like the Middle Eastern Abbasid caliphate and the […]
The Pacific Ocean is the deepest, largest ocean on Earth, covering about a third of the globe’s surface. An ocean that vast may seem invincible. Yet across its reach – from Antarctica in the south to the Arctic in the north, and from Asia to Australia to the Americas – the Pacific Ocean’s delicate ecology […]
“Did the Atlantic close and then reopen?” That was the question posed in a 1966 paper by the Canadian geophysicist J. Tuzo Wilson. The answer? Yes, over millions of years. And it was the breakup of the supercontinent Pangea, starting some 180 million years ago, that began creating the Atlantic Ocean basin as we know […]
The history of Earth climate is characterized by a succession of glacial and interglacial periods. However, although climate change is inherent to Earth, the observed trend of temperature increase over the past century cannot be explained by climate models which include solar irradiance and are only explicable by the rise in greenhouse gases. Mauna Loa […]
Imagine a bucket filled with hard spheres. As these spheres are free to pack together as closely as geometry allows they tend to adopt a close-packed structure, a structure in which there is least unfilled space. X-ray diffraction studies reveal that many metallic elements have close-packed structures. This simple fact explains a couple of very […]
Something weird is happening in Mexico these days. Two powerful earthquakes have hit the country in two weeks. The second one occurred exactly on the same date of the thirty-second anniversary of the most damaging quake known in the country and the early warning system did not work properly. Even more: two hurricanes are causing […]
We’ve known for decades there was a time when mammoths, saber-tooth cats, and other big mammals walked the Earth like it was no big deal. We also know that at some point of the Ice Age, a mass extinction made them disappear, leaving their fossils and their descendants as the only proof of their existence […]
Over geologic time scales, seawater transforms the basalt of the ocean floor by chemical attack. At the end of this alteration process, the basalt turns partly into clays and partly into dissolved salts in sea water. Lithium, a chemical element initially contained in basalt, will then be distributed between clay and seawater. This separation has […]