The Guardian looks at efforts to map Doggerland, a prehistoric area of land in the North Sea between Britain and continental Europe that was submerged by rising sea levels at the end of the last ice age. “Using seabed mapping data the team plans to produce a 3D chart revealing the rivers, lakes, hills and coastlines of the country. Specialist survey ships will take core sediment samples from selected areas to extract millions of fragments of DNA from the buried plants and animals.”
The bare bones of Tharp’s story are therefore fairly well known: while mapping the floor of the Atlantic Ocean, she discovered the presence of the Mid-Atlantic Ridge—and, more specifically, its rift valley, providing tangible evidence of continental drift. Because continental drift was at that point considered to be a crackpot theory, it took some doing for Tharp’s discovery to be accepted; and when it was her contributions were to some extent minimized.
While Felt’s book is positioned as a biography, its strength is in the details of that pivotal discovery: how and where it was made, and by whom, and in what context. Tharp’s work was not done in a vacuum, and how and why she was where she was is important. Felt sets the stage for us: not only does she take us through Tharp’s early childhood and rather variegated education and her arrival in 1948 at the Lamont Observatory, she gives us a short history of that Observatory, of the theory of continental drift, of her colleagues—notably her lifelong collaborator (and possibly life partner) Bruce Heezen and Observatory director (and sometime antagonist) Maurice Ewing. More than anything else, Soundings provides context for Tharp’s discovery: by the time we’re done, we know how important it was, and why. We’ve been well briefed.
Felt is less successful in building a portrait of Tharp herself. Some areas of her non-work life—her childhood, family and college education, for example—are extremely well covered, but other areas have considerable gaps, particularly those involving her personal life. The nature of Tharp’s relationship with Heezen is only hinted at, as is an early, unsuccessful marriage to someone else. Her later life, supported by a motley gang of eccentrics called Tharpophiles, is also incompletely covered. The elisions, however unintended, are frustrating. I suspect the author was a prisoner of her source material, which in places she follows very closely; I would have liked it if more had been done to fill in the gaps.
Soundings was published in hardcover by Henry Holt in 2012. It’s available in paperback and ebook from Picador.
This image went a bit viral earlier this week. Some context. It’s from an August 2015 blog post at Le Cartographe, in which Alexandre Nicolas discussed (and rendered, above) a projection produced in 1942 by South African oceanographer Athelstan Spilhaus. In Spilhaus’s oceanic projection, centred on Antarctica, the world’s oceans form a single, uninterrupted body of water. Which, you know, it is. The continents form the edges of the map; there is … some … spatial distortion. As Alexandre wrote in 2015, “This projection is rarely used and it’s a real shame!”
On the WMS Facebook group, Bert Johnson had this to say about this latest profile: “Hers is a standout story, but I wish some of these journalists who keep running these would spend some time and effort discussing some of the other women—known and unknown—who made contributions and helped open the doors of cartography to women.”
Global sea level rise has been accelerating in recent decades, according to a new study based on 25 years of NASA and European satellite data. This acceleration has been driven mainly by increased ice melting in Greenland and Antarctica, and it has the potential to double the total sea level rise projected by 2100[. …]
The rate of sea level rise has risen from about 2.5 millimeters (0.1 inch) per year in the 1990s to about 3.4 millimeters (0.13 inches) per year today. These increases have been measured by satellite altimeters since 1992, including the TOPEX/Poseidon, Jason-1, Jason-2, and Jason-3 missions, which have been jointly managed by NASA, France’s Centre national d’etudes spatiales (CNES), the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), and the U.S. National Oceanic and Atmospheric Administration (NOAA). The maps on this page depict the changes in sea level observed by those satellites between 1992 and 2014.
The Australian government has released high-resolution sea floor map data of the Great Barrier Reef; the data improves the view of the relief by a factor of eight, from 250-metre resolution to 30-metre resolution. The result of a collaboration between James Cook University, Geoscience Australia and the Australian Hydrographic Service, the data “can be used for policy, planning and scientific work. For example, this data is an important input for oceanographic modelling, which we can use to enhance our knowledge of climate change impacts, marine biodiversity, and species distribution.” Press release, data files.
In the 1770s British surveyor George Gauld mapped the Florida Keys, taking careful note of the location and depth of Florida reefs. A study published last month in Science Advances compares Gauld’s maps with modern-day satellite imagery and concludes that half of the area occupied by coral in the eighteenth century has disappeared. As the Washington Post reports, the cause of the coral’s disappearance is unclear, though several potential human and natural factors are put forward. [WMS]
This short profile of Marie Tharp — the third I’ve seen this year — is notable in that it’s at JSTOR Daily, and links to two of the research papers she co-authored with Bruce Heezen (both of which appear free to access, but require a JSTOR account). Direct links here and here. [WMS]
To date, more than 85 percent of the seafloor has not been mapped using modern methods. Since 70 percent of the Earth is covered in oceans, this means that we quite literally don’t know our own planet. “We know the surface of Mars better than we do the seafloor,” says Martin Jakobsson, a researcher at Stockholm University.