floor

Deep sea mining

August 19, 2024 By EarthWise Leave a Comment

Deep sea mining is the extraction of minerals from the ocean floor at depths greater than 660 feet and as much as 21,000 feet below the surface. Active or extinct hydrothermal vents on the ocean floor create sulfide deposits which collect metals such as silver, gold, copper, manganese, cobalt, and zinc. This forms polymetallic nodules – potato-sized rocklike deposits containing these valuable minerals. There are literally trillions of these things scattered over wide areas of ocean floor. The largest of these deposits are in the Pacific Ocean between Hawaii and Mexico in the Clarion Clipperton Fracture Zone.

Mining companies argue that land-based sources for valuable metals are running out and are critically needed for green technologies like batteries for electric vehicles and manufacturing solar panels and wind turbines. They also claim that mining in the deep sea will be less environmentally damaging than land-based mining.

The deep sea is viewed by many as kind of a watery desert but there are actually diverse and rich ecosystems down there. Most of the animals living in the depths are tiny, but that doesn’t make them any less important. Many can live for a very long time. Some invertebrates live for thousands of years.

There are currently no commercial deep sea mining operations underway. Many countries have outlawed them.

The deep seas are the last mostly unexplored part of the Earth. Deep sea mining will unquestionably be highly destructive to these environments. We don’t really know what the impact of widespread deep sea mining might be, but the world continues to edge ever closer to allowing it to happen.

**********

Web Links

Can We Mine the World’s Deep Ocean Without Destroying It?

Photo, posted March 30, 2018, courtesy of the NOAA Office of Ocean Exploration and Research via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

California Offshore Wind | Earth Wise

June 28, 2021 By EarthWise Leave a Comment

Offshore wind has been pretty much a non-starter in the U.S. until recently. Now there is considerable activity in the Northeast Atlantic with major projects getting started off the coasts of Massachusetts, New York, and other eastern states. The prospects for wind farms in the Pacific, on the other hand, have been pretty dismal. There are significant logistical problems posed by a deep ocean floor and also opposition from the Navy that does not want obstacles for its ships.

A combination of progress in floating wind turbine technology and the arrival of an administration highly supportive of renewable energy technology has changed the situation. In late May, the Navy abandoned its opposition to Pacific offshore wind and joined the Interior Department in giving support to allowing two areas off the California coast to be developed for wind turbines.

The plan allows commercial offshore wind farms in a 400-square-mile area in Morro Bay in central California, and in another area off the Humboldt Coast in Northern California.

The two California sites could support enough wind turbines to generate electricity to power 1.6 million homes. That would make the California coast one of the largest generators of wind power in the world. The forthcoming Vineyard Wind farm in Massachusetts is expected to have 84 giant turbines. The two California sites could hold more than 300 turbines.

The offshore wind industry is booming around the world, especially near the coasts of Norway and the UK, where the water is shallow, and turbines can be anchored to the ocean floor. By contrast, the Pacific Ocean floor drops steeply from the coastline, making it too deep to anchor wind towers. The newly emerging technology of floating turbines is the key to establishing offshore wind in the Pacific.

**********

Web Links

Biden Opens California’s Coast to Wind Farms

Photo, posted August 7, 2013, courtesy of Ray Bouknight via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Vanishing Kelp Forests | Earth Wise

June 25, 2021 By EarthWise Leave a Comment

Bull kelp is the dominant species in offshore kelp forests north of Santa Cruz, California along the west coast of North America. Bull kelp has similar physical structures to terrestrial plants; it anchors to the ocean floor with root-like structures called holdfasts, and has stem-like structures called stipes from which leaf-like blades stretch out through the water, absorbing nutrients and sunshine.

These giant seaweeds form lush underwater forests in northern California’s coastal waters and have long provided critical habitat for many species like salmon, crabs, and jellyfish. But now, for much of the California coast, only a few patches of bull kelp remain.

A team from University of California Santa Cruz has studied satellite images of about 200 miles of coastline. They found that starting in 2014, the area covered by kelp has dropped by more than 95%.

The die-off was driven in part by an underwater heat wave that depleted nutrients in the water and made it harder for the kelp to grow. Making matters much worse, populations of purple sea urchins, which eat kelp, have exploded in the region because of overfishing and other reductions in urchin predators such as sea otters. The sea urchins eat kelp holdfasts, creating so-called urchin barrens where their destructive grazing has decimated kelp forests.

Bull kelp is a species at high risk of becoming endangered. In coming decades, more marine heatwaves are expected. These events as well as stronger El Niños will become more common and frequent with climate change. Between these thermal events and the sea urchins, it will be difficult for kelp forests to survive.

**********

Web Links

Ninety-five percent of bull kelp forests have vanished from 200-mile stretch of California coast

Photo, posted October 28, 2015, courtesy of Florian Graner/Green Fire Productions via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Turning CO2 Into Rock

January 6, 2020 By EarthWise Leave a Comment

As the world continues to struggle to find ways to reduce carbon emissions, there is increasing attention being paid to so-called negative emission technologies (NET), which remove and permanently sequester carbon dioxide from the atmosphere.

The University of Victoria in British Columbia has brought together an international team of experts to explore the possibilities of permanently and safely sequestering CO2 as rock beneath the ocean floor. The Solid Carbon Project seeks to extract carbon dioxide directly from the air and then, using deep-ocean technology powered by offshore solar and wind energy, inject it into sub-seafloor basalt, where it would mineralize into solid carbonate rock.

When CO2 is injected into porous basalt, a type of volcanic rock, it reacts relatively quickly with minerals to form solid carbonate, thereby permanently removing it from the atmosphere. Because 90% of the planet’s basalt is located beneath the ocean floor, the deep ocean is the place to do this kind of carbon sequestration.

The team includes experts in ocean science, carbon mineralization, renewable energy, engineering design, and oil-and-gas drilling/injection operations. Other experts are focusing on the social and legal implications of the NET technology.

Over the next four years, the Solid Carbon Project will assess the integration of multiple existing technologies that will be needed to successfully develop this kind of carbon storage. One of these is the direct air capture technology itself, which will need to be adapted to a renewable energy-powered offshore platform. The best outcome technologies explored by the project will be selected for a real-world demonstration at Ocean Networks Canada’s observatory site, 9,000 feet underwater in the Cascadia Basin, off the coast of British Columbia.

**********

Web Links

A rock-solid solution for CO2

Photo courtesy of the University of Victoria.

Earth Wise is a production of WAMC Northeast Public Radio.

Community Action And Coral Reefs

January 1, 2020 By EarthWise Leave a Comment

Coral reef habitats are some of the densest and most varied ecosystems on earth. While coral reefs cover just 0.2% of the ocean floor, scientists estimate that nearly one million different species of fish, invertebrates, and algae can be found in or around coral reefs.

However, climate change is wreaking havoc on the health of coral reefs. Warming and acidifying oceans are resulting in enormous coral losses. Overfishing, development, and pollution are also threatening coral reef health.

According to new research, positive community action can help boost fish populations in coral reefs and safeguard future fish numbers. The paper, which was recently published in the journal Proceedings of the National Academy of Sciences, details the social and ecological outcomes of work being done in Papua New Guinea since 2001.

These communities have established a traditional system of rotational fishing closures in order to manage their fisheries resources. They ban fishing on part of their reefs for a few years, and then open these closures when village elders believe fish behavior has changed and fish populations have recovered. They then close a different part of their reefs, and repeat the process.

The researchers found that these rotational practices resulted in more than twice as many fish on the closed reefs as compared to open ones, and the closures made fish less scared of people and easier to catch. But the researchers did caution that this short term boost in fish numbers may not be enough to stop the overall impact of fishing.

Globally, more than 500 million people depend on coral reefs for food, income, and coastal protection. Balancing community needs with environmental needs can be tricky business.

**********

Web Links

Positive community action can help coral reef health

Photo, posted October 11, 2011, courtesy of Paul Toogood via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.