Deep-sea mining could destroy unique habitats hidden inside metal-rich nodules

2:19

supplementary video · The Guardian on YouTube ↗

nature & planetPhys.org

Deep-sea mining could destroy unique habitats hidden inside metal-rich nodules

from Phys.org

In the extreme depths of the Pacific Ocean, there are small, metal-bearing formations that are far more than just valuable sources of raw materials. A new study published in the journal Scientific Reports shows that polymetallic nodules serve as specialized habitats for tiny organisms.

explained

Deep sea mining is the extraction of minerals from the seabed of the deep sea, mainly polymetallic nodules found at depths of 4–6 km on the abyssal plain. These nodules contain metals such as copper, nickel, cobalt and manganese, which make up roughly 30% of their weight, and the Clarion–Clipperton zone alone holds over 21 billion metric tons of them. It matters because studies suggest mining plumes can harm marine life well beyond the mining area, and so far only exploratory licenses have been issued.

Background adapted from Wikipedia: Deep sea mining ↗ · text CC BY-SA 4.0

how it works

Metals dissolved in seawater and seeping from sediments slowly precipitate around a small core such as a shark tooth or shell fragment, adding a thin layer over very long timescales, on the order of millimetres per million years. Because the seabed around them is soft mud, the nodules are the only hard ground for sponges, corals and microbes to settle on.

so what

Companies want the nodules as a source of battery metals, while scientists warn that the habitat they provide can't regrow on human timescales. The finding adds to the debate over whether deep-sea mining can be done without permanent loss of life on the abyssal plains.

Trump and Netanyahu reportedly clash over whether to resume military action against Iran

the gist

Israeli reports also say the cabinet directed the military to prepare for a possible new attack on Iran.

so what

The United States and Israel have been closely aligned on Iran's nuclear programme and regional threats, so open disagreement between their leaders over military strategy is unusual and closely watched. Whether to resume strikes is a decision with consequences for shipping, oil markets and the wider Middle East.

fun fact

Benjamin Netanyahu has served as Prime Minister of Israel for more years in total than any other person.

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Data: GDELT Project

Illustrative photo · Israel Belkind and Fanny Abramovitch (original) “The Provis…, Public domain, via Wikimedia Commons

10:49

supplementary video · Epimetheus on YouTube ↗

world cultures & travelWikivoyageclassic9th–15th century · Siem Reap, Cambodia

Angkor was the largest pre-industrial city on Earth, covering about 3,000 square kilometres

the gist

Angkor, near Siem Reap in northern Cambodia, was the capital of the Khmer Empire, which ruled much of mainland Southeast Asia between roughly the 9th and 15th centuries. At its height the city spread across about 3,000 square kilometres, making it the largest pre-industrial city on Earth by area. Its growth depended on water: huge reservoirs called barays, along with canals and embankments, stored monsoon rain and carried it to rice fields. That system let farmers harvest more than once a year and fed a very large population through the dry season. The temple complex of Angkor Wat, built in the early 12th century, is the best-known monument and still stands at the heart of the park.

how it works

The Khmer kings built enormous rectangular reservoirs that caught monsoon rain during the wet season. Earthen dykes and canals moved that water into rice paddies, so farmers could grow crops across much of the year. The surplus food supported craftsmen, builders and the workforce that raised the temples.

so what

Angkor shows how a society without industrial machinery could build a city on a scale that rivals modern metropolises, using engineering and water management instead. Some historians link its decline to drought, flooding and shifts in its water systems, which makes it a long-running case study in how cities depend on managing water. The site is a UNESCO World Heritage Site and one of the most important archaeological landscapes in Southeast Asia.

fun fact

The outline of Angkor Wat appears on the national flag of Cambodia.