seawater

The Caspian Sea And Climate Change | Earth Wise

January 22, 2021 By EarthWise Leave a Comment

According to the National Oceanic and Atmospheric Administration, global sea levels have been rising over the past century, and the rate has increased in recent decades. Sea levels are currently rising about one-eighth of an inch every year.

Sea level rise is caused primarily by two factors related to climate change: the added water from melting glaciers and ice sheets, and the expansion of seawater as it warms. While climate change is causing global sea levels to rise, higher temperatures in other regions are having exactly the opposite effect. The water levels are falling.

According to researchers from the University of Bremen in Germany, the Caspian Sea is a perfect example of how a body of water will change. While it is named a sea due to its size and high salinity, the Caspian Sea is actually a lake. In fact, it’s the largest lake in the world. Its largest inflow is the Volga River and it has no natural connection to the ocean. Its water level is determined by the proportional influences of inflow, precipitation, and evaporation. Climate change is causing increased evaporation, which leads to a declining water level.

According to the research team, the water level of the Caspian Sea could fall by 29 to 59 feet during this century.

The Caspian Sea is surrounded by Kazakhstan, Turkmenistan, Iran, Azerbaijan and Russia. It’s an important regional water reservoir, and a biological and commercial center.

The researchers hope the Caspian Sea will be used as an example in scientific research to assess the vulnerability of other regions to falling water levels.

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Climate crisis is causing lakes to shrink

Photo, posted October 31, 2016, courtesy of Amanderson2 via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Using CO2 To Convert Seawater Into Drinking Water | Earth Wise

October 27, 2020 By EarthWise Leave a Comment

A chemist at the University of Copenhagen has invented a technology that uses carbon dioxide to convert seawater into drinking water within minutes. This desalination technology has the potential to replace electricity with CO2 and be used in survival gear and in large-scale industrial plants in places where people don’t have clean drinking water.

Over 800 million people worldwide lack access to clean drinking water and that number is growing rapidly. Seawater is a vital source of drinking water in many parts of the world, but desalination faces the major challenge of being highly energy intensive. Desalination plants use huge amounts of fossil fuel-generated electricity and therefore contribute to climate change.

The Copenhagen technology is reminiscent of a SodaStream machine. Carbon dioxide is added to water, initiating a chemical reaction. But instead of using it for bubbly carbonation, it is used to separate salt from water. It works by adding a chemical called CO2-responsive diamine to saltwater. The diamine compound binds with the added CO2 and acts as a sponge to absorb the salt, which can then be separated. The entire process takes one to ten minutes. Once the CO2 is removed, the salt is released again, allowing the diamine to be reused for several more rounds of desalination.

In the laboratory, the method removed 99.6% of the salt in seawater. The technology is still being developed to lower its price and optimize the recycling process. It is also being tested on a small scale in the form of water bottles fitted with special filters that can be used in lifeboats or in other outdoor settings. Ultimately, it could be used to greatly reduce the energy consumption of desalination plants.

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Chemist uses CO2 to convert seawater into drinking water

Photo, posted January 10, 2015, courtesy of Daniel Orth via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Plant-Based Bottles | Earth Wise

June 30, 2020 By EarthWise Leave a Comment

Single-use plastic soda and water bottles are a real problem. Every year, billions of them are produced – comprising nearly 300 million tons of plastic that mostly ends up in landfills or in the ocean. This discarded plastic ends up on remote islands, in the snow atop mountains, and in trenches in the deepest parts of ocean.

There has been increasing pressure on beverage companies to put an end to this environmental disaster, but the convenience and economy of disposable bottles is just too attractive.

These bottles are made of plastic derived from oil and once they are produced, they take decades or even centuries to decompose. Recycling them is a not-starter because it is cheaper to just make new ones.

A possible solution has emerged. A Dutch company called Avantium has found a way to take plant sugars and transform them into a plastic capable of standing up to carbonated beverages like soda and beer but that will also break down in as little as a year in a composter or 3 years if left exposed to the elements.

Coca Cola and Carlsberg are working with Avantium to develop new drink packaging based on their material that could be in stores as soon as 2023. The new packaging would be quite different from what we use today. Instead of a clear or tinted bottle, beverages would come inside a cardboard container with a liner made of plant-based plastic.

It may take a while for people to get used to the change, but we have already managed to get used to milk, juice and other liquids coming in cardboard containers instead of glass or plastic bottles. The benefits to the planet would make the effort well worthwhile.

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Plant-Based Bottles Could Degrade In One Year

Photo courtesy of Avantium.

Earth Wise is a production of WAMC Northeast Public Radio.

Harvesting Blue Energy | Earth Wise

February 7, 2020 By EarthWise Leave a Comment

There are various ways to generate renewable energy from the world’s oceans, most obviously from the power of tides and waves. But there is also an oceanic energy source called osmotic or “blue” energy. Osmotic energy uses the differences in pressure and salinity between freshwater and saltwater to generate electricity.

When freshwater and saltwater are mixed together, large amounts of energy are released. If the freshwater and seawater are then separated via a semi-permeable membrane, the freshwater will pass through the membrane and dilute the saltwater due to the chemical potential difference. This process is called osmosis. If the salt ions are captured completely by the membrane, the passing of water through the membrane will create a pressure known as osmotic pressure. This pressure can be used to generate electricity by using it to drive a turbine. This has been demonstrated to work as far back as the 1970s, but the materials we have to use are not adequate to withstand ocean conditions over the long term and tend to break down quickly in the water.

New research, published in the journal Joule, looked to living organisms for inspiration to develop an improved osmotic energy system. Scientists from the U.S. and Australia combined multiple materials to mimic the kind of high-performance membranes that are found in living organisms. They created a hybrid membrane made from aramid microfibers (like those used in Kevlar) and boron nitride. The new material provides both the flexibility of cartilage and the strength and stability of bone.

The researchers believe that the low cost and high stability of the new hybrid membrane will allow it to succeed in volatile marine environments. They also expect the technology will be both efficient and scalable.

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Inspired by the Tissues of Living Organisms, Researchers Take One Step Closer to Harvesting “Blue Energy”

Photo, posted February 14, 2017, courtesy of Marian May via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Much More Microplastics In The Ocean | Earth Wise

January 28, 2020 By EarthWise Leave a Comment

We’ve been hearing more and more about plastic contamination (microplastics) in the ocean. It is pulled from the nostrils of sea turtles, found in Antarctic waters, and tracked in increasing quantities in sedimentary layers dating back to the 1940s. A new study by researchers from the Scripps Institution of Oceanography suggests that there could be a million times more pieces of plastic in the ocean than previously estimated.

Oceanographers found that some of the tiniest countable microplastic particles in seawater occur at much higher concentrations than previously measured. Apparently, the traditional way of counting marine microplastics most likely misses the smallest particles, and therefore underestimates the number of particles by a factor of anywhere from 10,000 to a million.

The new measurements estimate that the oceans may be contaminated by 8 million pieces of so-called mini-microplastics per cubic meter of water. Earlier studies that only looked at larger pieces of plastic found only 10 pieces per cubic meter.

Microplastic studies typically trawl or pull a fine net behind a ship to collect samples. But the meshes previously used could only capture plastics as small as 333 microns. The new study found plastic particles as small as 10 microns, which is less than the width of a human hair.

Plastics keep breaking down into smaller and smaller particles, but they are so chemically strong that their chemical bonds don’t break down. They remain bits of plastic. Scientists are concerned that these particles can get small enough to enter the human bloodstream. The potential effects on human health are not well known and not extensively studied.

The problem of plastics just keeps getting bigger.

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Microplastics a million times more abundant in the ocean than previously thought

Photo courtesy of UC San Diego.

Earth Wise is a production of WAMC Northeast Public Radio.

Ocean Acidification And Mass Extinction

November 26, 2019 By EarthWise Leave a Comment

Since the industrial revolution, the concentration of carbon dioxide in the atmosphere has increased due to the burning of fossil fuels and land use changes. The ocean absorbs about 30% of the CO2 that is released in the atmosphere. As the levels of atmospheric CO2 increase, so do the levels in the ocean.

When CO2 is absorbed by the ocean, a series of chemical reactions occur, resulting in seawater becoming more acidic. Ocean acidification threatens calcifying organisms, such as clams and corals, as well as other marine animals, like fish. When these organisms are at risk, the entire marine ecosystem may also be at risk.

In fact, according to research recently published in the journal Proceedings of the National Academy of Sciences, fossil evidence from 66 million years ago has revealed that ocean acidification can cause the mass extinction of marine life. Researchers analyzed seashells in sediment laid down shortly after a giant meteorite hit earth. This strike wiped out the dinosaurs and 75% of marine species. Chemical analysis of the shells revealed a sharp drop in the PH of the ocean over hundreds of years after the meteorite strike. The meteorite impact vaporized rocks, causing carbonic acid and sulphuric acid to rain down, acidifying the ocean. The strike also resulted in mass die-off of plants on land, increasing atmospheric CO2.

Researchers found that the pH dropped by 0.25 pH units in the 100 to 1,000 years after the meteorite strike. Alarmingly, scientists expect the pH of the ocean to drop by 0.4 pH units by 2100 if our carbon emissions continue as projected.

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Ocean acidification can cause mass extinctions, fossils reveal

Photo, posted March 16, 2017, courtesy of Zachary Martin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Floating Solar Fuel Farms

September 20, 2019 By EarthWise Leave a Comment

Limiting global warming will require a massive reduction in CO2 emissions from fossil fuel burning. Renewable energy sources are playing a growing role in the power grid and electric cars are becoming increasingly popular. Despite all this, carbon-based liquid fuels will continue to dominate our energy use for the foreseeable future.

Researchers in Norway and Switzerland have described a potential scheme that would help remove CO2 from the atmosphere and produce a valuable liquid fuel.

The idea is to create floating islands containing large numbers of solar panels that convert carbon dioxide in seawater into methanol, which can fuel airplanes and trucks.

A combination of largely existing technologies would be the basis of these floating islands, which would be similar to present-day floating fish farms. The researchers envision clusters each composed of 70 circular solar panels that in total cover an area of roughly half a square mile. The solar panels would produce electricity, which would split water molecules and isolate hydrogen. The hydrogen would then react with carbon dioxide pulled from seawater to produce usable methanol.

The technology already exists to build the floating methanol islands on a large scale in areas of the ocean free from large waves and extreme weather. Suitable locations are off the coasts of South America, North Australia, the Arabian Gulf, and Southeast Asia.

A single floating solar farm could produce more than 15,000 tons of methanol a year – enough to fuel a Boeing 737 airliner for more than 300 round-trip flights across the country. Floating energy islands would not be a magic bullet for limiting the effects of climate change, but they could well be an important part of an overall strategy.

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Giant Floating Solar Farms Could Make Fuel and Help Solve the Climate Crisis, Says Study

Photo courtesy of PNAS.

Earth Wise is a production of WAMC Northeast Public Radio.

Fresh Water Under The Sea

July 18, 2019 By EarthWise Leave a Comment

A new survey of the sub-seafloor off the U.S. Northeast coast has revealed the existence of a gigantic aquifer of relatively fresh water trapped in porous sediments lying beneath the salty ocean. This appears to be the largest such formation ever found.

The newly-discovered aquifer stretches from the shore at least from Massachusetts to New Jersey and extends more-or-less continuously out about 50 miles to the edge of the continental shelf. The deposits begin at around 600 feet below the ocean floor and bottom out at about 1,200 feet. If all that water was found on the surface, it could create a lake some 15,000 miles in area. The researchers estimate that the region holds at least 670 cubic miles of fresh water.

Researchers made use of innovative measurements of electromagnetic waves to map the water, which had not been detected by other technologies. It was already known that fresh water existed in places under the sea bottom as a result of oil drilling as far back as the 1970s. But there was previously no hint of the extent of the undersea aquifer.

The water probably was trapped by sediments deposited during the last ice age when sea levels were much lower. But modern subterranean runoff from land sources might also be a contributor.

If water from the aquifer was to be withdrawn, it would still have to be desalinated for most uses, but the cost would be much less than processing ordinary seawater. There is probably no need to do this in the Northeastern US, but the discovery suggests that such aquifers probably lie off many other coasts worldwide and could provide desperately needed water in places like southern California, Australia, the Mideast or Saharan Africa.

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Scientists Map Huge Undersea Fresh-Water Aquifer Off U.S. Northeast

Photo, courtesy of August 1, 2015, courtesy of Michael Vadon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A New Way to Make Hydrogen

January 31, 2019 By EarthWise Leave a Comment

Many people consider hydrogen to be the fuel of the future, both for powering vehicles and for storing energy generated by renewable sources. Hydrogen itself is a clean and green fuel. Generating energy from it using fuel cells results in only water as a byproduct.

The biggest problem with hydrogen is that the most economical way to produce it and therefore the way most hydrogen is produced today, is by reforming natural gas, which is a process that generates carbon emissions.

The desirable way to make hydrogen is to produce it by breaking apart water into its hydrogen and oxygen components, a process known as electrolysis. There are many ways to do it, but none of them to date measures up in terms of efficiency, cost, and longevity.

Researchers at the University of Toronto have recently developed a new catalyst that uses abundant, low-cost elements to split water molecules into hydrogen and oxygen. The catalyst is made from copper, nickel, and chromium, all of which are more abundant and less costly than platinum, which is the usual electrolysis catalyst.

The new catalyst performs well under pH-neutral conditions, which means it could even work on seawater without incurring the expense of desalination. The Toronto researchers also believe their catalyst could be used as part of a process to make hydrocarbon fuels from hydrogen and CO2₂. Their group is among the five finalists in the Carbon XPrize competition, which has a grand prize of $7.5 million for finding a way to convert waste CO2 into fuel.

Finding a low-cost, energy-efficient, and reliable way to make hydrogen out of water will be a big deal if it can be done on an industrial scale.

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U of T researchers discover low-cost way to produce hydrogen from water

Photo, posted July 23, 2015, courtesy of Magnus Johansson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sustainable Plastics

January 28, 2019 By EarthWise Leave a Comment

According to the United Nations, plastic accounts for up to 90% of all the pollutants in the ocean. Conventional plastics take hundreds of years to decay, so all the plastic that gets into the oceans piles up and endangers marine life and pollutes the environment. Unfortunately, there are few comparable, environmentally friendly alternatives.

An often-proposed solution is bioplastics, which are not made from petroleum and degrade quickly. The downside of bioplastics is that growing the plants or bacteria used to make the plastic requires fertile soil and fresh water, which are scarce commodities in many places.

One such place is Israel. So, researchers there at Tel Aviv University have developed a process to make a bioplastic polymer that doesn’t require land or fresh water. The new polymer is derived from microorganisms that feed on seaweed. It is biodegradable, produces zero toxic waste and recycles into organic waste.

The polymer is called polyhydroxyalkanoate, or PHA for short. The raw material is multicellular seaweed, cultivated in the ocean. These algae are eaten by single-celled microorganisms, which also grow in salty seawater and produce a polymer that can be used to make bioplastic. PHA is already produced in commercial quantities, but it is currently made from plants that require agricultural land and fresh water. The new process would enable countries with limited fresh water, such as Israel, China and India, to switch from petroleum-based plastics to biodegradable plastics.

Plastics from fossil sources are one of the world’s biggest pollution problems. The new study shows that it is possible to produce bioplastic completely based on marine resources in an environmentally-friendly process.

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