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The human impact on oceans

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Vast and powerful, the oceans have sustained human life around the world for millennia. They provide food, natural resources, and livelihoods, supporting countless communities and economies. But despite their size and resilience, the oceans are under increasing pressure from climate change and human activity, pushing them toward a dangerous threshold.

According to a new study led by researchers from UC Santa Barbara, the cumulative human impact on the oceans is forecasted to double by 2050, which is just 25 years from now.  These impacts include ocean warming, fisheries losses, sea level rise, acidification, and pollution.

The research team, which includes collaborators from Nelson Mandela University in South Africa, found that the tropics and poles will experience the fastest rate of change.  And coastal regions, where most human activity takes place, will bear the heaviest consequences of those changes. 

The research team calls the findings sobering – not only because the impacts are increasing, but because they’re increasing so quickly. 

The study, which was recently published in the journal Science, shows that ocean warming from climate change and reductions in marine biomass from overfishing are expected to be the two largest contributors to future ocean impacts.  If ecosystems cannot cope with these pressures, human societies will also feel the consequences.

But the research team stresses that it’s not too late. Stronger climate policies, better fisheries management, and protections for vulnerable habitats like salt marshes and mangroves could help slow or even reduce human impacts.

The research serves as both a warning, and a chance to act before it’s too late.

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Human impact on the ocean will double by 2050, UCSB scientists warn

Photo, posted July 11, 2018, courtesy of Ed Dunens via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

More trouble from sea urchins

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Sea Urchins are real troublemakers.  On the West Coast, the sea urchin population exploded when the sunflower sea stars that eat them were decimated by a wasting disease.  Urchins devour kelp and they ate up 96% of the region’s kelp forests.  Kelp forests serve as shelter and food for a vast array of marine life and kelp sequesters as much as 20 times more carbon than terrestrial forests.

A new study by researchers at North Carolina State University looked at the health of the coral reef in Honaunau Bay on Hawaii’s Big Island and found that ballooning sea urchin populations are endangering the survival of the reef.

Fishing in these areas has greatly reduced the numbers of fish that feed on sea urchins and urchin populations have grown significantly.   There are areas of the reef where there are 51 sea urchins in every square meter.

The reef is already not growing at a healthy rate as a result of water pollution and overheating created by climate change.  These result in a poor environment for coral to reproduce and grow, which leaves the reef unable to keep up with the pace of erosion caused by urchins.

Reef growth is measured in terms of net carbonate production – namely the amount of calcium carbonate produced over time.  In the 1980s, healthy reefs in Hawaii produced about 15 kilograms of carbonate a year per square meter.  The Honaunau Reef today shows an average net carbonate production of only 0.5 kilograms per square meter.  The reef is growing very slowly and can’t keep up with urchin erosion.

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Huge sea-urchin populations are overwhelming Hawaii’s coral reefs

Photo, posted October 29, 2017, courtesy of Rickard Zerpe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Sharks and rays in a warming world

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Sharks and rays belong to a group of cartilaginous fish called elasmobranchs, which have been swimming in the world’s oceans for 450 million years. The resilient species have survived five mass extinction events, and are older than dinosaurs, trees, and Mount Everest. 

But despite their resilience, many species of sharks and rays today are threatened by human activities, including overfishing, habitat loss, and climate change.  In fact, according to a new study led by researchers from the University of Vienna in Austria, more than one third of the shark and ray species known today are severely under threat. 

The study, which was recently published in the journal Biology, found that higher carbon dioxide levels were having a negative effect on sharks and rays, ranging from impacts on the animals’ senses to changes in the skeleton during embryonic development.  An examination of fossil records found that higher CO2 levels had contributed to the extinction of individual shark and ray species in the past. 

But the study also found that global warming could be creating opportunities for sharks and rays.  Rising sea levels and higher temperatures have historically expanded shallow coastal habitats and warm waters, supporting species biodiversity.

But according to the research team, the rapid environmental changes, combined with the impacts from human activities, outpace the ability of sharks and rays to adapt, making it unlikely that they will benefit from global warming.

Protecting sharks and rays is crucial not only for their survival but also for maintaining entire ocean ecosystems. Without top predators, these ecosystems could collapse, impacting both marine life and the people and industries that depend on it.

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Sharks and rays benefit from global warming – but not from CO2 in the Oceans

Myths About Sharks and Rays

Photo, posted November 27, 2007, courtesy of Laszlo Ilyes via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Value Of Seagrass | Earth Wise

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Seagrasses are found in shallow salty and brackish waters in many places around the world, from the tropics to the Arctic Circle.  They get their name from their long green, grass-like leaves.  They are not seaweeds at all but are more closely related to flowering plants on land. 

We hear a lot about threatened ocean ecosystems and most of the attention is on coral reefs and coastal mangrove forests.  Seagrass meadows get much less press, but they in fact provide wide-ranging services to society and store a great deal of carbon.

A new study by the University of Michigan demonstrates that seagrass ecosystems should be high up on the global conservation agenda.  The study puts a dollar value on the many services – which include storm protection, fish habitat, and carbon storage – provided by seagrasses in the Caribbean.  The numbers are enormous.

The researchers estimate that the Caribbean holds up to half of the world’s seagrass meadows by surface area, and it contains about a third of the global carbon storage by seagrasses.  They calculated that the Caribbean seagrasses provide about $255 billion in services to society each year, which includes $88 billion in carbon storage.

In the Bahamas alone, ecosystems services provided by seagrasses are valued at more than 15 times the country’s 2020 gross domestic product.

Blue carbon is the name used to describe carbon stored in coastal and open-ocean ecosystems.  The idea of selling blue carbon offset credits, which monetize the carbon stored in this way, is gaining traction.  For many Caribbean nations, this is likely to provide impetus for protecting seagrass ecosystems from human impacts, including nutrient pollution and overfishing.

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Caribbean seagrasses provide services worth $255B annually, including vast carbon storage, study shows

Photo, posted June 27, 2023, courtesy of Daniel Eidsmoe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Coral Reefs And Ecosystem Services

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A new study led by the University of British Columbia provides the first comprehensive look at what climate change, overfishing, and habitat destruction of coral reefs mean for their ecosystem services.  For humans, this means how the global decline in coral reefs has affected their ability to provide essential benefits including food, livelihoods, and protection from storms.

The study found that global coverage of living corals has declined by about half since the 1950s and the diversity of reef species has declined by more than 60%.  So, it is no surprise that there has been a significant loss in the ability of reefs to provide ecosystem services.

The study analyzed data from coral reef surveys around the world, fisheries catches, indigenous consumption, and more.  Apart from the declines in reef coverage and biodiversity, the study found that fish catches on coral reefs peaked in 2002 and has steadily declined since then, despite increased fishing efforts.

The findings of the study led the researchers to conclude that continued degradation of coral reefs in the years to come threaten the well-being and sustainable development of millions of people in communities on the coast that depend on coral reefs.  Fish and fisheries provide essential nutrients in places with few alternative sources of nutrition.  Coral reef biodiversity and fisheries have added importance for indigenous communities, where important cultural relationships exist with reefs.

The study’s authors say that the results are a call to action.  The level of destruction happening all over the world’s coral reefs is threatening people’s culture, their daily food, and their history.  It is not just an environmental issue; it is a human rights issue.

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Photo, posted September 22, 2010, courtesy of David Burdick / NOAA Photo Library via Flickr.

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Protecting The Ocean Has Multiple Benefits | Earth Wise

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An international team of authors from 18 institutions has recently published a paper in the journal Nature that offers a solution that addresses several of humanity’s most pressing problems at the same time.  The paper provides a comprehensive assessment of where strict ocean protection can contribute to a more abundant supply of healthy seafood, help address climate change, and protect embattled species and habitats.

The study identified specific areas of the ocean that could provide all of these benefits if they were protected.  Currently, only about 7% of the ocean is under any kind of protection.  According to the study, if the appropriate 30% of the ocean was protected by the actions of the relevant countries by 2030, the cited benefits would be realized.

Safeguarding these regions would protect nearly 80% of marine species while increasing fishing catches by almost 9 million tons a year. It would also prevent the release of more than 1 billion tons of carbon dioxide by protecting the seafloor from bottom trawling, which is a widespread and destructive fishing practice.

Ocean life has been declining worldwide because of overfishing, habitat destruction, and climate change.  The study pioneers a new way to identify the places that – if protected – will boost food production and safeguard marine life, while at the same time reducing carbon emissions.  The study finds that countries with large national waters and large industrial trawl fisheries have the highest potential to contribute to climate change mitigation by protecting the carbon stored on the ocean floor.  The ocean covers 70% of the Earth and its importance in solving the challenges of our time must not be underestimated.

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Three Times the Gains

Photo, posted January 10, 2016, courtesy of Hafsteinn Robertsson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Saving The Queen Conch | Earth Wise

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Queen conchs are large sea snails belonging to the same taxonomic group as clams, oysters, and squid.  They live on coral reefs or seagrass meadows in warm, shallow waters.  Queen conchs are found throughout the Caribbean Sea and Gulf of Mexico, ranging as far north as Bermuda and as far south as Brazil.

Reaching up to 12” long and living up to 40 years, the queen conch is prized as a delicacy and revered for its shell.  It’s the second most important sea-bottom fishery in the Caribbean region, trailing only the spiny lobster. 

But queen conchs face a challenge.  Their populations are in a steady rate of decline as a result of overfishing, habitat degradation, and hurricane damage.  In some places, the numbers are so low that remaining conchs cannot find breeding partners.  The situation is urgent from both an ecological and economical perspective. 

As a result, Megan Davis, a scientist from Florida Atlantic University who spent more than four decades researching queen conch, has released an 80-page, step-by-step user manual about how to care for the species. Her work was recently published in the National Shellfisheries Association’s Journal of Shellfish Research.

According to Davis, aquaculture, along with conservation of breeding populations and fishery management, are ways to help ensure longevity of the queen conch.  With requests for mariculture guidance pouring in from communities throughout the Caribbean, Davis and her collaborators are expanding their queen conch conservation, education, and restorative mariculture program.

Their desired outcomes include creating protected breeding areas, establishing sustainable hatcheries, and repopulating protected habitats.

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‘Hail to the queen’: Saving the Caribbean queen conch

Photo, posted June 3, 2012, courtesy of Christopher Gonzalez via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sharks On The Decline | Earth Wise

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During the past 70 years, global shark populations have been on the decline.   Many species have become threatened or endangered.  Conservation efforts have been underway in many places, but shark populations continue to be at risk because of over-fishing and habitat loss.

A comprehensive study by marine biologists at Texas A&M University deployed more than 15,000 baited remote underwater video stations on 371 coral reefs in 58 countries.   The study included 59 different shark species in the Atlantic, Pacific and Indian Oceans.  The researchers were surprised to find that no sharks at all were detected in almost 20% of the locations surveyed and were almost completely absent from coral reefs in several nations. 

Scientists believe that demand for shark products, such as fins and meat, and bycatch (that is, sharks captured in nets by fisherman trapping other kinds of fish) are strong contributors to the widespread declines in shark numbers around the world.

The study shows that if corrective steps are not taken in regions where marine management is still ineffective, continued depletion of shark populations is highly likely. 

Sharks have important roles in marine ecosystems.  When their habitats deteriorate and their populations decrease, ecosystem stability and health is degraded because sharks help regulate prey populations.

Some countries, notably the Bahamas, are combating the problem by providing sanctuaries for sharks where fishing and harvesting is prohibited.  Such places support some of the healthiest shark populations in the world.  However, the decline of coral reefs is just another challenge facing shark populations around the world.

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Study Shows Alarming Decline In Shark Numbers Around The World

Photo, posted January 9, 2017, courtesy of Kris-Mikael Krister 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.

Community Action And Coral Reefs

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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.  

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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.

One Million Extinctions

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A group of 145 expert authors from 50 countries has produced a report based upon a review of 15,000 scientific and government sources that is the first comprehensive look at the state of the planet’s biodiversity in 15 years.  The conclusions are alarming.

Thanks to human pressures, one million species may be pushed to extinction in the next few years, something with serious consequences for human beings as well as the rest of life on earth.

Based upon scientific studies as well as indigenous and local knowledge, the evidence is overwhelming that human activities are the primary cause of nature’s decline.  The report ranked the major drivers of species decline as land conversion, including deforestation; overfishing; bush meat hunting and poaching; climate change; pollution; and invasive alien species.

The tremendous variety of living species on our plant which number at least 8.7 million and perhaps many more – biodiversity – constitutes a life-supporting safety net that provides our food, clean water, air, energy, and more.

In parts of the ocean, little life remains but green slime.  Some remote tropical forests are nearly silent because insects have vanished.  Many grasslands are becoming deserts.  Human activity has severely altered more than 75% of Earth’s land areas and has impacted 66% of the oceans.  The world’s oceans increasingly are characterized by plastics, dead zones, overfishing, and acidification.

The main message of the 1,500-page report is that transformative change is urgently needed.  In order to safeguard a healthy planet, society needs to shift from a sole focus on chasing economic growth.  This won’t be easy, but we must come to the understanding that nature is the foundation for development before it is too late.

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One million species at risk of extinction, UN report warns

Photo, posted January 1, 2014, courtesy of Eric Kilby via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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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Breeding Dory

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The regal blue tang is one of the most common and most popular marine aquarium fish in the world.  In the U.S., they have been ranked as high as the 10th most imported fish species out of over 2,000 that enter the country.  Apart from aquarium hobbyists, millions of people now associate blue tangs with the character Dory in a couple of popular animated films.

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Cod And Global Warming

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Atlantic cod has been the basis of a major fishing industry in the Gulf of Maine for centuries and is a key species in the local ecosystem.  Overfishing decimated the population of cod and in 2010, fisheries managers imposed a series of restrictions on harvesting the fish in order to try to help the species to rebound.

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