mussels

Wind farms and sea farms

August 5, 2024 By EarthWise Leave a Comment

There has been increasing use of agriculture coexisting with solar farms. This dual use of land is a win-win situation. Recently, Danish researchers have been investigating the potential for farming marine products at offshore wind farms.

Scandinavia’s largest wind farm, Kriegers Flak, is the site of a four-year-old project in which long lines are stretched between the wind farm’s pylons and are used to grow mussels and seaweed. With the first harvest that has taken place after 18 months, it is showing signs of early success.

Seaweed and mussels are low trophic aquaculture crops. That means that that they don’t need to be fed or fertilized. They take up nutrients from the sea and produce healthy foods.

The 328-foot lines spread between the turbines can be used to grow substantial quantities of the underwater seafood. According to modeling by Aarhus University – the institution conducting the study – using just a tenth of Denmark’s wind park area could produce tons of seafood annually while using only the naturally-available resources. This form of aquaculture captures emissions instead of producing them.

Researchers say that it is time to develop guidelines to encourage companies to plan for multiple uses of the ocean because countries are ramping up production of clean energy from offshore wind farms. Denmark was the first country in the world to install a commercial offshore wind park in 1991. Over 30 years later, nearly half of the country’s electricity comes from wind turbines.

The benefits of such sea farms combined with offshore wind farms go beyond food production and clean energy production. They also help improve water quality and capture carbon. It is another win-win situation.

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Beneath offshore wind turbines, researchers grow seafood and seaweed

Photo, posted August 5, 2007, courtesy of Andreas Klinke Johannsen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Floating cities

June 6, 2024 By EarthWise Leave a Comment

About 40% of the world‘s population lives in coastal regions. People really like ocean-front property. But worldwide, rising sea levels mean that more and more people want to live on land that may someday be swallowed up by the sea.

One possible solution to the problem is to build cities on top of the water. It sounds pretty futuristic and impractical, but it is starting to happen. There have long been floating communities in places like the Netherlands, but these are for the most part clusters of houseboats moored close together.

But there are far more ambitious projects underway. The Maldives Floating City, already under construction, will eventually have 5,000 houses located in a lagoon that is a 15-minute boat ride from the capital city of Male. The housing units will be tethered to the lagoon floor and linked together.

A new project, located off Busan, South Korea, will combine high and low technology to create a large-scale, on-water town, that can house more than 10,000 people.

The town will be built on enormous concrete platforms suspended on the water. The platforms float because they are rounded hexagonal boxes that are buoyed up by Archimedes’’ principle. They can’t sink. Such structures will attract marine life, providing places for oysters and mussels, for example, to grow.

The initial development will cover 15 acres and the infrastructure will handle power, water, waste, and even some food. The goal is even to produce enough energy to provide some to the nearby community. A bridge will link the community to the land.

The project is scheduled to be completed in 2028. Future expansion could end up housing 150,000 people.

Floating cities could soon no longer be exotic or futuristic.

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Are Floating Cities the Solution to Rising Seas?

Photo, posted June 5, 2012, courtesy of Raymond Bucko via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Below-Average Dead Zone In The Gulf of Mexico | Earth Wise

July 20, 2023 By EarthWise Leave a Comment

The Gulf of Mexico dead zone, or hypoxic area, is an area of low oxygen content that can kill fish and other marine life. It occurs every summer and is mostly a result of excess nutrient pollution from human activities in cities and farms throughout the Mississippi River watershed. The nutrients carried by the river into the gulf stimulate an overgrowth of algae, which eventually die and decompose, which depletes oxygen in the water as the algae sink to the bottom.

The resultant low oxygen levels near the bottom of the gulf cannot support most marine life. Fish and shrimp often leave the area seeking better places to be. Animals that can’t swim away – like mussels and crabs – can be stressed by the low oxygen level or even killed.

The National Oceanic and Atmospheric Administration produces a dead zone forecast each year based on a suite of models developed by NOAA and partners at multiple universities.

The latest forecast, completed in May, found that the discharge of nutrients in the rivers was about one-third below the long-term average between 1980 and 2022. Nitrate loads were down 42% and phosphorous levels down 5%.

Based on these measurements, the scientists forecast a summer dead zone that will cover an estimated 4,155 square miles, which is 22% lower than the 36-year average of 5,364 square miles. Ongoing efforts by the Interagency Mississippi River and Gulf of Mexico Hypoxia Task Force to reduce nutrient levels seem to be paying off.

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NOAA forecasts below-average summer ‘dead zone’ in Gulf of Mexico

Photo, posted September 6, 2013, courtesy of NOAA Photo Library via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Polar Bears and Tires | Earth Wise

January 12, 2023 By EarthWise Leave a Comment

There is lots of interest in traction. People want to find better ways to move across wet and frozen surfaces safely. This applies to both the shoes on our feet and the tires on our cars.

Researchers at the University of Akron along with colleagues at Syracuse University and at Bridgestone, the tire company, have been studying how many arctic animals can walk and run across the ice without slipping and falling. Their research focused on the paws of polar bears.

Previous studies discovered that polar bears have papillae – little bumps on the pads of their feet – that provide improved traction on snow. The new research also looked at the paws of other species of bear – brown bears and black bears – and found that these others also have papillae on their paw pads, but that those of polar bears are as much as 50% taller. These taller bumps give the pads a 30-50% increase in frictional shear stress.

The research may lead to various applications. For example, snow tires typically have deeper treads, but the polar bear study may lead to some new designs that would improve traction. People who do high-altitude climbing are interested in the research as are companies that deliver goods in bad weather. Anyone who has to be out and about in bad weather would like to get a better grip.

There are various other animals with traction-improving adaptations that are probably worth studying. These include dogs, wolves, foxes, and mountain goats. The same researchers at Akron have also studied other animals with unique abilities to deal with challenging surfaces including geckos, spiders, and mussels. The natural world is filled with examples of creatures who can easily function in environments that we humans find very challenging.

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UA researchers’ focus on tire traction leads to investigation of polar bear paws

Photo, posted March 2, 2008, courtesy of Sam Weng via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Cleaning Up Urban Rivers With Nature’s Tools | Earth Wise

October 7, 2022 By EarthWise Leave a Comment

Fifty years after the passage of the Clean Water Act, urban waterways across the United States are continuing their comeback and are showing increasing signs of life. A strategy that is being adopted in many places is to use natural restoration techniques focused on bolstering plants and wildlife to improve water quality.

A nonprofit called the Upstream Alliance has focused on public access, clean water, and coastal resilience in the Delaware, Hudson, and Chesapeake watersheds. Working with the Center for Aquatic Sciences and with support from the EPA and the National Fish and Wildlife Foundation, the alliance has been repopulating areas of an estuary of the Delaware River near Camden, New Jersey with wild celery grass, which is a plant vital to freshwater ecosystems.

In many places, scientists, nonprofits, academic institutions, and state agencies are focusing on organisms like bivalves (typically oysters and mussels) along with aquatic plants to help nature restore fragile ecosystems, improve water quality, and increase resilience.

Bivalves and aquatic vegetation improve water clarity by grounding suspended particles, which allows more light to penetrate. These organisms also cycle nutrients both by absorbing them as food and by making them more available to other organisms.

Underwater restoration projects have been underway in New York Harbor for more than a decade, where the Billion Oyster Project has engaged 10,000 volunteers and 6,000 students.

The hope is that bringing back bivalves and aquatic plants can create a lasting foundation for entire ecosystems. It is restoring nature’s ability to keep itself clean.

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How Using Nature’s Tools Is Helping to Clean Up Urban Rivers

Photo, posted December 19, 2019, courtesy of Scott via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Invasive Species On Ships In Antarctica | Earth Wise

February 23, 2022 By EarthWise Leave a Comment

The Southern Ocean around Antarctica is the most isolated marine environment on Earth. Antarctica’s native species have been isolated for the last 15-30 million years. As a result, wildlife there has not evolved the ability to tolerate the presence of many groups of species.

New research by the University of Cambridge and the British Antarctic Survey has traced the global movements of all the ships entering Antarctic water and has found that Antarctica is connected to all regions of the globe via ship activity to an extent much greater than previously thought. Fishing, tourism, research, and supply ships are exposing Antarctica to invasive, non-native species that threaten the existing ecosystems.

In all, the research identified over 1,500 ports with links to Antarctica. From all these places, non-native species including mussels, barnacles, crabs, and algae attach themselves to ships’ hulls. The process is known as biofouling.

The greatest concern is the movement of species from pole to pole. These species are already cold-adapted. They may come on tourist or research vessels that spend the northern hemisphere summer in the Arctic before traveling south for the Antarctic summer season.

Mussels have no competitors in Antarctica should they be accidentally introduced. Shallow water crabs would introduce a new form of predation that Antarctic animals have never encountered before.

Current biosecurity measures to protect Antarctica, such as cleaning ships’ hulls, focus on a small group of so-called gateway ports. The new findings indicate that these measures need to be expanded to protect Antarctic waters from non-native species.

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Invasive species ‘hitchhiking’ on ships threaten Antarctica’s unique ecosystems

Photo, posted April 12, 2016, courtesy of NOAA’s National Ocean Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Mollusks And Microplastics | Earth Wise

January 26, 2021 By EarthWise Leave a Comment

Plastic debris comes in all different shapes and sizes, but pieces that are less than five millimeters in length are called microplastics. Microplastics are everywhere, including in the food we eat, the water we drink, and the air we breathe.

Much of the oceanic microplastic pollution comes from the breakdown of plastic litter. Another source of microplastic pollution is microbeads. Microbeads, which are sometimes added to cleansing and exfoliating personal care products, pollute the environment when they get flushed down the drain.

According to a new study by researchers at Hull York Medical School and the University of Hull in the U.K., mussels, oysters and scallops have the highest levels of microplastic contamination among seafood. The research team examined 50 studies between 2014 and 2020 to determine the levels of microplastic contamination globally in fish and shellfish. The team found that microplastic content was 0-10.5 microplastics per gram in mollusks, 0.1-8.6 microplastics per gram in crustaceans, and 0-2.9 microplastics per gram in fish.

The researchers found that mollusks collected off the coasts of Asia were the most heavily contaminated with microplastics. China, Australia, Canada, Japan and the United States are among the largest consumers of mollusks, followed by Europe and the U.K.

While the human health implications of consuming microplastics are not well understood, early evidence from other studies suggest they do cause harm.

According to the research team, more data is needed from different parts of the world in order to better understand how microplastics vary between different oceans, seas, and waterways.

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