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The Gulf Of Mexico Dead Zone | Earth Wise

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Every summer, a so-called dead zone forms in the Gulf of Mexico.  It is primarily caused by excess nutrient pollution from human activities in urban and agricultural areas throughout the Mississippi River watershed. 

When these excess nutrients reach the Gulf, they stimulate excess growth of algae, which eventually die and decompose, depleting oxygen as they sink to the bottom.  These low oxygen levels near the Gulf bottom cannot support most marine life.  Animals that are sufficiently mobile – such as fish, shrimp, and crabs – generally swim out of the area.  Those that can’t move away are stressed or killed by the low oxygen.

A team of scientists funded by the National Oceanic and Atmospheric Administration issues an annual forecast for the dead zone based upon a suite of models that incorporate river flow and nutrient data. 

The 2021 forecasted area is somewhat smaller than, but close to, the five-year measured average for the dead zone, which is 5,400 square miles, roughly the size of the state of Connecticut.   Each year, these forecasts are reported as comparisons to long-term averages, but the problem is that the long-term average is unacceptable.

The Interagency Mississippi River and Gulf of Mexico Hypoxia Task Force has set a goal of reducing the size of the dead zone to a five-year average of 1,900 square miles – about a third of the current average.

Large reductions in nutrient loads have been called for in federal and state action plans for nearly 20 years, but clearly these reductions have not yet been sufficient. The Interagency Task Force continues to provide information for managing nutrient loads in the Mississippi River Basin. 

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Average-sized ‘dead zone’ forecast for Gulf of Mexico

Photo, posted October 6, 2020, courtesy of Christine Warner via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wind Farms Slowing Each Other Down | Earth Wise

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Offshore wind is booming in Europe.  The expansion of wind energy in the German Bight and Baltic Sea has been especially dramatic.  At this point, there are about 8 gigawatts of wind turbines in German waters, the equivalent of about 8 nuclear power plants.  But space in this region is limited so that wind farms are sometimes built very close to one another.

A team of researchers from the Helmholtz Center Hereon, a major German research institute, has found that wind speeds downstream from large windfarms are significantly slowed down.  In a study published in the journal Nature Scientific Reports, they found that this braking effect can result in astonishingly large-scale lowering of wind speeds.

On average, the regions of lowered wind can extend 20-30 miles and, under certain weather conditions, can even extend up to 60 miles.  As a result, the output of a neighboring wind farm located within this distance can be reduced by 20 to 25 percent.

These wake effects are weather dependent.  During stable weather conditions, which are typically the case in the spring in German waters, the effects can be especially large.  During stormy times, such as in November and December, the atmosphere is so mixed that the wind farm wake effects are relatively small.

Based on their modeling, it is clear that if wind farms are planned to be located close together, these wake effects need to be taken into account.  The researchers next want to investigate the effects that reduced wind speeds have on life in the sea.  Ocean winds affect salt and oxygen content, temperatures, and nutrients in the water.  It is important to find out how reduced winds might affect marine ecosystems.

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Are wind farms slowing each other down?

Photo, posted November 23, 2011, courtesy of David J Laporte via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sunscreen And Coral Reefs | Earth Wise

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The dangers of overexposure to UV solar radiation have led to the extensive production and use of sunscreen products.  It is generally understood that many of the chemical compounds used in sunscreen products have toxic effects on marine organisms, but research in this area is relatively limited.

There are estimates that as many as 82,000 kinds of chemicals from personal care products have made their way into the world’s oceans.  In 2015, it was estimated that around 14,000 tons of sunscreen are ending up in the world’s coral reefs per year and causing irreparable damage.

Eighty-five percent of the Caribbean’s coral reefs died before the turn of the century, not as a result of global warming, but because of pollution.  Oxybenzone and octinoxate are two of the common sunscreen ingredients that are most toxic to corals.  Preservatives like parabens are also toxic.

There are much safer sunscreens such as those based on zinc oxide or titanium oxide.  In some places, such eco-friendly sunscreens are mandatory.  Sunscreens with SPF values above 30 contain a higher percentage of chemicals and have been shown to not really provide any more protection than SPF 30 products.

Apart from the choice of sunscreen product, if one really wants to reduce the negative impact sunscreen has on reefs and marine life, wearing sun-protective clothing such as rash-guards will allow the use of much less sunscreen and therefore result in less of it entering the ocean.

Products that can help protect against the harmful effects of UV radiation on human health are extremely important, but it is also important to identify and quantify the risks associated with these products to reef ecosystems.

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How to Know If Your Sunscreen Is Killing Coral Reefs — and the Brands to Try Instead

Impacts of sunscreen on coral reefs needs urgent attention, say scientists

Photo, posted January 11, 2015, courtesy of Elch Korallen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Marine Life Moving The Wrong Way | Earth Wise

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As the oceans have warmed in recent decades, various marine species ranging from whales to corals have begun to shift poleward in search of cooler waters.  But a new study, reported in the journal Nature Climate Change, found that many sedentary marine species – including snails, worms, and mussels – are actually being transported in the wrong direction.

What is happening is that bottom-dwelling species – also known as benthic species – in the northwest Atlantic Ocean are spawning earlier in the year because of the warmer water temperatures.  But earlier in the year is when ocean currents travel southward.  As a result, the larvae of these animals are being carried into warmer waters rather than cooler ones, threatening their survival and shrinking their ranges.  These larvae grow into adults in these warmer regions and are basically trapped there.  This creates a feedback loop where the situation for the species gets worse and worse.  Species like common sand dollars and the economically important blue mussel have had a 30 to 50% contraction of their ranges.

The result is that a number of bottom-dwelling species that previously were quite abundant have entirely disappeared from the outer shelf.

The researchers at Rutgers University likened this “wrong-way migration” of bottom-dwelling marine life to so-called elevator-to-extinction events that have been taking place in mountainous regions.  This is where species such as birds and butterflies move to higher and higher elevations to escape rising temperatures until there is nowhere else for them to go.

The essential fact that this research reveals is that species don’t necessarily move to places where the climate is congenial for them.  They may unfortunately end up migrating to even worse conditions.

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As Oceans Warm, Some Species Are Moving in the Wrong Direction

Photo, posted June 10, 2016, courtesy of James_Seattle via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Mangrove Trees And Climate Change | Earth Wise

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Mangrove trees are small trees that grow in coastal saline or brackish water at tropical and subtropical latitudes.  Many mangrove trees can be identified by their dense tangle of prop roots.  These roots make the trees appear as if they are standing on stilts above the water.  The tangle of roots allows mangrove trees to handle the daily rise and fall of tides and to slow the movement of tidal waters.  

Mangrove forests provide many ecosystem services, including stabilizing the coastline by reducing erosion from storm surges, waves, and tides.  The intricate root system of mangrove trees are attractive to fish and other species seeking food and shelter from predators.  Mangrove forests also store large amounts of carbon.     

But according to a new study recently published in the journal Science, mangrove trees won’t survive sea level rise by 2050 if greenhouse gas emissions aren’t reduced.  

Using sediment data from 78 locations over the last 10,000 years, an international team of scientists led by Macquarie University in Australia estimated the chances of mangrove trees survival based on the projected rates of future sea-level rise.

When sea level rise rates exceeded 6 millimeters per year, which is similar to estimates under high-emissions scenarios for 2050, researchers found that mangrove trees were unlikely to keep pace with the rising water levels.  But when the annual increase was 5 millimeters or less – which is the projected low-emissions scenario this century – mangrove trees are much more likely to survive. 

These findings underscore the importance of reducing greenhouse gas emissions to mitigate rapid sea level rise.  The future of mangrove trees may depend on it.  

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Mangrove trees won’t survive sea-level rise by 2050 if emissions aren’t cut

Photo, posted December 17, 2012, courtesy of Edward Stojakovic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Dead Zone In The Gulf Of Mexico | Earth Wise

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The Gulf of Mexico has an area of low to no oxygen in the water that can kill fish and other marine life.  It is an annual event that is primarily caused by excess nutrient pollution from human activities in urban and agricultural areas throughout the Mississippi River watershed.   When these excess nutrients reach the Gulf, they stimulate the overgrowth of algae, which eventually die and decompose, depleting the oxygen in the water as the algae sink to the bottom.

These low oxygen levels near the bottom of the Gulf cannot support most marine life.  Some species – among them many fish, shrimp, and crabs – swim out of the area, but animals that can’t swim or move away are stressed or killed by the low oxygen.  The dead zone in the Gulf occurs every summer.

A recent forecast for this summer’s dead zone predicts that the area of low or no oxygen will be approximate 6,700 square miles, which is roughly the size of Connecticut and Delaware combined.  This is about 1,100 square miles smaller than last year’s dead zone and much less than the record of 8,776 square miles set in 2017.  But it is still larger than the long-term average size of 5,387 square miles.

Making comparisons to the long-term average ignores the fact that the long-term average itself is unacceptable.  The dead zone not only hurts marine life, but it also harms commercial and recreational fisheries and the communities they support.  The actions that have been taken so far to reduce pollution in the Mississippi watershed are clearly not sufficient to drastically reduce the dead zone in the Gulf.

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Large ‘dead zone’ expected for Gulf of Mexico

Photo, posted October 17, 2017, courtesy of NOAA’s National Ocean Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Giant U.S. Offshore Wind Project Begins | Earth Wise

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In recent years, the Bureau of Offshore Energy Management – the agency that oversees energy projects in federal waters – has been granting leases for offshore wind projects in the waters of multiple states on the East Coast.  Up until now, none of these leases have actually resulted in the deployment of any wind turbines because the process of gaining approvals, project plans, surveys, funding and other requirements is a long and tortuous one.

In late May, the first offshore wind turbine in U.S. federal waters was installed 27 miles offshore from Virginia.  The 6-MW Siemens turbine is one of two turbines making up the Coastal Virginia Offshore Wind pilot project.  The pilot project is expected to be operational later this year.  This project is the first to receive go-ahead approval by the BOEM.

The CVOW project is a development by Dominion Energy, a Virginia-based utility that operates in 20 states.  Dominion’s project will eventually be a 2.64 GW mega-farm that could be the largest offshore wind farm in the world.  Construction of the main project is expected to begin in 2024.  It will be sited in the seabed of a 112,800-acre lease area.  The site is currently being surveyed to determine potential impacts to ocean and sea life.

Dominion Energy has made multiple commitments to emissions reduction and the massive offshore wind farm is an important part of its efforts to meet those commitments.  The CVOW pilot project is only the second offshore wind installation in the U.S.  The first, the Block Island Wind Farm in Rhode Island, is in state waters and did not require BOEM approval.

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A ‘monumental day’ for US offshore wind as first turbine is installed in federal waters

Photo, posted May 13, 2011, courtesy of the Department of Energy and Climate Change via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Recovering Marine Life By 2050 | Earth Wise

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Marine life has faced challenges for a long time.   There have been centuries of overfishing in many places and pollution of various types has been especially harmful in recent decades.   But despite all of this, a new scientific review published in the journal Nature contends that marine life in the world’s oceans could be fully restored in as little as 30 years provided that aggressive conservation policies are adopted.

The research spotlights the strong resiliency of ocean animals and cites the successful recovery of a number of marine species, including humpback whales.

The study indicates that nations around the world must agree to designate 20 to 30 percent of the oceans as marine protected areas, institute sustainable fishing guidelines, and regulate pollution.  These measures would not come cheaply.  The estimated cost would be around $20 billion a year. 

However, the report also estimates that the economic return on this investment would be tenfold and would create millions of new jobs.  Rebuilding fish stocks and maintaining sustainable fishing policies could increase global profits of the seafood industry by over $50 billion a year.  Conserving coastal wetlands could save the insurance industry more than $50 billion a year as well by reducing storm damage.

A major sticking point, however, is climate change.  Climate change is increasing ocean temperatures and driving acidification.  Unless these changes are brought under control, the restoration of marine life is not going to be successful.  We have reached the point where it is within our power to choose between a future with a resilient and vibrant ocean or an irreversibly disrupted ocean.  Whether we embrace that challenge remains to be seen.

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Marine Life Could Recover By 2050 With the Right Policies, Study Finds

Photo, posted April 20, 2012, courtesy of Matthias Hiltner via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Dolphins

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We don’t think of heatwaves as something that affects the ocean, but increasingly, as the planet warms, there have been instances where ocean water temperatures become much higher than normal for extended periods of time.  There has been much discussion of this phenomenon with regard to coral reefs where the catastrophic rise in coral bleaching events has been the result.

Recently, a study at the University of Zurich looked at the effects of ocean heatwaves on marine life higher in the food chain.  They studied the well-known dolphin population in Shark Bay, Western Australia.

In early 2011, a heatwave caused water temperatures in Shark Bay to rise more than 4 degrees above the annual average for an extended period.  This led to a substantial loss of seagrass, which is a driving factor in the Shark Bay ecosystem.

The researchers investigated how this environmental damage affected survival and reproduction of dolphins, using long-term data on hundreds of animals collected over a ten-year period from 2007 to 2017.

Their analysis showed that dolphins’ survival rate dropped by 12% and female dolphins were giving birth to fewer calves.  That phenomenon that began in 2011 lasted at least until 2017.

The researchers were surprised by the extent and the duration of the influence of the heatwave, especially the fact that the reproductive rate of dolphins had not returned to normal even after 6 years.

This study shows for the first time that marine heatwaves not only affect organisms at the lower levels of the food chain, but also might have considerable long-term consequences for the animals at the top, such as dolphins.

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Climate change is a threat to dolphins’ survival

Photo, posted December 14, 2014, courtesy of Ed Dunens via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sustainable Plastics

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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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Sustainable ‘plastics’ are on the horizon

Photo, posted March 14, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Australian Plastic Bag Ban

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Last summer, the two largest supermarket chains in Australia – Coles and Woolworth’s – decided to stop offering single-use disposable plastic bags to customers.  The initial public reaction was decidedly negative.   However, within just three months after the radical change, the country’s National Retail Association reported an 80% drop in the consumption of plastic bags nationwide.

In that three-month period, it is estimated that 1.5 billion bags have been prevented from use.   Some retailers are reporting reduction rates as high as 90% in the use of the bags.  The move by the big supermarkets has paved the way for smaller businesses to follow suit. The smaller businesses typically can’t afford to risk the wrath of their customers with a major change like this. Customers have to learn to bring their own bags or buy reusable bags at the store.

In much of Australia, the phase-out of plastic bags has been legislated, but the state of New South Wales, home to Sydney, the country’s largest city, has not enacted such legislation. So, supermarkets themselves are doing the work of getting rid of the bags.

The change has not been without hiccups.  For the first couple of months after the plastic bag ban was put in place, Woolworth’s saw poor sales in its stores.  However, customers eventually got used to the new way of doing things and sales levels returned.

Disposable plastic bags often find their way into the oceans where they break down into microparticles. Studies have shown that these plastic bits are ingested by a wide variety of marine life.  For example, a UK study found that 100% of sea turtles in the Pacific and Atlantic oceans as well as the Mediterranean Sea had plastic in their digestive systems.

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Australia-wide ban leads to ’80 per cent drop’ in plastic bag consumption

Photo, posted September 18, 2018, courtesy of Matthew Paul Argall via Flickr.  

Earth Wise is a production of WAMC Northeast Public Radio.

Cleaning Up the Garbage Patch

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We have been talking about the Great Pacific Garbage Patch for several years.  Two years ago, we reported on the activities of a company called Ocean Cleanup, founded five years ago by an 18-year-old Dutch entrepreneur named Boyan Slat.  Two years ago, the company was conducting comprehensive surveys of the patch, which covers an area twice the size of Texas and contains some 80,000 tons of plastic debris.

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Where Does The Plastic Go?

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The glut of plastic in the oceans is a global problem.  About 9 million tons of plastic enter the oceans each year.  Much of it is discarded fishing gear, plastic bags, and other macroscopic objects.  But a great deal of it is in the form of microplastics or small particles.  Some microplastics come from cosmetics and other products containing them but a lot of them are the result of larger plastic objects breaking down into small particles.

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New Zealand Bans Plastic Bags

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In an effort to tackle plastic pollution, New Zealand is joining a growing list of countries banning single-use plastic bags for good.  Prime Minister Jacinda Ardern says in a press statement that the ban was necessary to safeguard New Zealand’s clean and green reputation.

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An Accidental Plastic Eater

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A couple of years ago, scientists in Japan discovered bacteria at a recycling plant that were breaking down a type of plastic called polyethylene terephthalate, or PET.  With the world facing a growing plastic pollution problem, British and American researchers began to study the enzyme that the bacteria were using to try to understand how it works.

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Carbon And The Dark Ocean

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Sunlight entering the water can travel as much as 3,000 feet into the ocean depths under the right conditions, but ordinarily there is no significant light that penetrates beyond about 650 feet down.  That upper 650 feet is called the euphotic or “sunlight” zone and is home to most familiar marine life.  The “dark ocean”, everything below that depth, makes up 90% of the ocean and remarkably little is known about it.

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Corals Like Plastic

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Microplastics, which are tiny pieces of weathered plastic less than 5 millimeters in diameter, have been accumulating in the oceans for the past 40 years and are now ubiquitous in the marine environment.  They are a major threat to many kinds of marine life, including numerous species of birds, turtles, fish, marine mammals and invertebrates who ingest the stuff causing a variety of problems.

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Looking For “Super Coral”

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Coral reefs are essential for much of marine life and are the basis of many commercial fisheries.  In places from Florida to Australia, they are major tourist attractions.  Estimates are that the economic impact of coral reefs is more than $375 billion a year.  And apart from all of that, they are some of the most beautiful places on the planet.

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New Rules For Ocean Conservation

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In a recent report to a United Nations ocean conference, scientists are warning that new rules are desperately needed to protect marine life in the open seas.  That’s because more than 60% of the ocean has no conservation rules since it’s located outside national jurisdictions.  The open ocean is at risk from climate change, over-fishing, deep sea mining, farm pollution, and plastics pollution. 

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