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More mosquitoes in a warming climate

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Over millions of years, Earth’s climate has warmed up and cooled down many times. However, today the planet is warming much faster than it ever has over human history.  According to scientists, the warming is primarily the result of increased anthropogenic greenhouse gas emissions.  In fact, human activities are responsible for nearly all of the increase in atmospheric greenhouse gas emissions over the last 150 years. 

According to a new study published in the journal Ecology, the warming climate may soon mean more mosquitoes.  A research team, led by scientists from Virginia Commonwealth University, found that rising temperatures, often linked to climate change, can make predators of mosquito larvae less effective at controlling mosquito populations.  According to researchers, these warmer temperatures accelerate the development time of larvae, which leads to a smaller window of time in which predators like dragonflies could eat them.  As a result, twice as many mosquito larvae could make it to adulthood in the study area. 

Predators help stabilize ecosystems and food webs.  The study looked at predator-prey interactions between dragonfly nymphs and mosquito larvae.  In the study of Belle Isle along the James River in Richmond, Virginia, the research team found that warmer pools had more aquatic rock pool mosquito larvae – even when their predators that naturally control the populations were present.

While this species of mosquito is not an important disease vector, the researchers emphasize that these findings likely apply to other mosquito species that do act as vectors for diseases, such as West Nile or Zika virus.

The changing climate is creating the perfect environment for mosquitoes to thrive. 

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Hotter weather caused by climate change could mean more mosquitos, according to VCU-led study

Photo, posted June 20, 2014, courtesy of John Tann via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Great Salt Lake Is Disappearing | Earth Wise

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Utah’s Great Salt Lake is the largest saltwater lake in the western hemisphere.  According to data from the US Geological Survey, the surface water elevation of the Great Salt Lake has fallen to the lowest level since records began in the mid-1800s.  The average elevation is now 4,190 feet above sea level.   With this drop in water level, the surface area of the lake is little more than half of its historical size.  The lower water level has exposed about 700 square miles of previously submerged lakebed.

The lake now contains about a quarter of the volume of water that it did at its high point in 1987.  The precipitous drop in water is a result of water usage from the lake coupled with climate change-fueled drought.   Increased water demand is due to the rapidly growing population of metropolitan Salt Lake City.  Utah’s population is projected to increase by almost 50% by 2060.

The Great Salt Lake goes though seasonal cycles of water loss and replenishment.  Rain and snow generally refill its level.  However, because of the ongoing megadrought in the West, water evaporation and depletion continue to exceed the amount of water entering the lake.  The water levels are expected to further decrease until fall or early winter, when incoming water is expected to equal or exceed evaporation.

The decline of the Great Salt Lake is a serious threat to the economy, ecology, and people of northern Utah.  The lake generates snowpack, is a refuge for hundreds of migratory birds and other wildlife and generates millions of dollars in the economy through mineral extraction and tourism.

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Utah’s Great Salt Lake is disappearing

Photo, posted October 6, 2020, courtesy of Julie Girard via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Transmission Lines And Wildlife Habitat Connectivity | Earth Wise

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Electrical transmission lines and their support towers tend to be a blight on the landscape but are something modern society cannot avoid.  Power transmission networks – with towers every 200 meters or so of line – are in place throughout the world’s developed nations.  Another common feature of developed nations is the fragmentation of animal species caused by human activity breaking up their natural habitats.

It is important for biodiversity conservation for animals to get their environments connected.   It turns out that transmission line infrastructure can provide an important tool for reconnecting wildlife habitats.

In a study conducted in Spain’s Andalusia region, scientists planted native shrubs and seedlings under six towers along power lines running through cereal cropland.  The area of each tower base was 100 square meters.

Compared to four control sites, the researchers measured increased population density and diversity among arthropods and small mammals observed in the four-year study. 

Enhancing connectivity through networks of habitat corridors or stepping-stone patches has become a key concept in conservation biology and landscape ecology.  Renting or buying large parcels of land to connect protected natural areas to one another would be cost prohibitive but planting suitable native shrubs and other flora under existing transmission line networks can provide many of the same benefits.

In general, power companies pay rent to landowners – often farmers or agribusinesses – for the rights to place towers on their land.  Because it is difficult to work the areas under towers with farm equipment, that space is typically unused, which opens the door to low-cost efforts by environmentalists.

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Electrical transmission lines have power to enhance habitat connectivity for wildlife

Photo, posted April 29, 2018, courtesy of Georgi Todorov/digitalnovas.com via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Oil Platforms And Fish | Earth Wise

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It is well-known that offshore oil platforms become major habitats for fish.  Their support structures rise hundreds of feet through the water column and basically create a prefabricated reef for marine life.   Many of these platforms will soon be decommissioned and government agencies are considering the consequences to undersea life when this happens.

Researchers at the University of California Santa Barbara have looked at how various decommissioning scenarios would affect undersea ecosystems. They found that completely removing a platform could reduce fish biomass by an average of 95%.  In contrast, removing just the top part of the rig could keep losses to around 10%.

California is looking at several possibilities for decommissioning 27 oil platforms off of its coast.  The three options are:  leave the platform in place, remove all of it, or remove just the top part of it.  Each option entails its own economic and ecological consequences.

The research team studied the size and composition of fish communities at 24 platforms and created models for each of the decommissioning scenarios.  The partial removal approach involved stripping away all structures within 26 meters of the surface.  This number would eliminate the need for a lighted buoy where the support structure remained according to U.S. Coast Guard guidelines.

For the 24 structures studied, leaving them entirely in place would support over 29,000 kilograms of fish biomass.  Removing just the top 26 meters would support nearly 28,000 kilograms.  Removing the platforms entirely would support only 500 kilograms of fish biomass.

As California weighs how to decommission its oil platforms, studies like this will be critical to making informed decisions.

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Oil Platforms’ Fishy Future

Photo, posted June 4, 2019, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

PPE Pollution | Earth Wise

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While the COVID-19 pandemic and its shutdown of so many human activities has reduced many kinds of pollution, it has also managed to create a new source of pollution:  face masks and sanitary gloves.

Divers from a French non-profit organization called Operation Clean Sea are already finding gloves, masks, and hand sanitizer bottles beneath the waves of the Mediterranean, along with the usual litter of disposable cups and aluminum cans. In France, authorities have ordered 2 billion disposable masks. Given that, there may soon be the risk of having more masks in the Mediterranean than jellyfish.  In Hong Kong, face masks have been piling up on beaches and nature trails.  Even in Hong Kong’s isolated and uninhabited Soko Islands, dozens of masks are showing up on a small stretch of beach.

Disposable masks may feel like soft cotton, but almost all of them are made from non-biodegradable material such as polypropylene.  When such masks are discarded into storm drains, they end up in rivers and seas.  With a lifespan of hundreds of years, these masks are an ecological timebomb.  Land-based activity accounts for 80% of ocean pollution, and half of that is a direct result of single-use plastics.  Many of the CDC’s recent recommendations for reopening offices and businesses actually recommend the increased use of them, and for sensible reasons.

The best we can all do is to wear reusable masks and to try to wash our hands more often rather than putting on another pair of latex gloves.  Given that there are alternatives, we don’t need to make plastic the solution to protect us from Covid-19.

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COVID-19 Masks Are Polluting Beaches and Oceans

Photo, posted March 28, 2020, courtesy of Michael Swan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Forest Regrowth In The Amazon | Earth Wise

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The Amazon is the largest tropical rainforest in the world.  It covers an area approximately equal in size to the lower 48 states, and is home to an estimated 10% of the world’s biodiversity and 15% of its freshwater.  These so-called “lungs of the planet” provide many important global ecological services, including carbon storage, and regulating air quality and climate.

Deforestation in the Amazon exploded in the 1970s and remains one of its biggest threats today.  Since the 1970s, more than 20% of the Amazon rainforest has been cleared.  Cattle ranching, soy and palm plantations, logging, and climate change are some of the biggest drivers of deforestation.  

Now, according to a new study recently published in the journal Ecology, the regrowth of Amazonian forests following deforestation may happen more slowly than previously thought.  These findings could have significant impacts on climate change predictions as the ability of forest regrowth in the Amazon – so-called secondary forests – may have been overestimated.  The research, which was conducted in Bragança, Brazil and includes two decades of forest monitoring, reveals that climate change and the wider loss of forests could be hampering regrowth.    

After 60 years of regrowth, the research team found that secondary forests only held 40% of the carbon when compared with forests undisturbed by humans.  Secondary forests also take less carbon from the atmosphere during periods of drought, and climate change is increasing the number of drought-years in the Amazon.  (During their 20 years of monitoring, the researchers also found biodiversity levels in secondary forests were only 56% of those seen in undisturbed forests). 

More long-term studies are needed to better understand the impacts of reforestation efforts.  

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Amazon forest regrowth much slower than previously thought

Photo, posted September 6, 2009, courtesy of Nao Lizuka via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Road Salt Pollution

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Mirror Lake is a popular recreational lake located in the Village of Lake Placid.  It is the most developed lake within the Adirondack Park, which is a publicly protected area that is actually larger than Yellowstone, Yosemite, Glacier, and Grand Canyon National Parks combined.

New research has revealed that road salt runoff into Mirror Lake is preventing natural water turnover which poses a risk to the balance of its ecology.  The study, which was published in Lake and Reservoir Management, found that road salt runoff is preventing spring mixing of the water column.    This creates more anoxic water conditions, meaning there is less oxygen in the water, and limits the ability of the habitat to support the native lake trout. 

Mirror Lake is the first lake in the Adirondack Park to show an interruption in lake turnover due to road salt.  Many lakes in northern climes experience so-called “dimictic turnover”, which is a natural process where wind and less stratified water conditions of spring and fall allow mixing of the water column that redistribute oxygen and nutrients throughout the lake.  High levels of surface-water chloride introduced into the lake from road salt runoff inhibit the mixing of the water column.

The lack of mixing and oxygenation is bad news for fish species such as lake trout, which require cold, oxygenated water to survive.  It may also put the lake at a greater risk of algal blooms.

Mirror Lake is small, surrounded by concentrated development, and receives the direct discharge of stormwater.  So, it is particularly vulnerable to road salt contamination.  Other lakes elsewhere in New York may experience similar conditions.  The researchers are confident that natural turnover conditions could be restored to the lake if road salt application in the watershed is reduced.

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Road salt pollutes lake in one of the largest US protected areas, new study shows

Photo, posted January 5, 2018, courtesy of MTA of the State of NY via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Eco-Friendly Agriculture

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Modern agriculture has steadily destroyed native grasslands, among other ecosystems.  In fact, farming is one of the most ecologically destructive things that humans do.  But we do have to eat.  In response, there is a growing movement for agrarian reform, from grain farming on the prairie, to agroforestry, to raising livestock more sustainably.  Efforts are accelerating to develop a kinder, gentler agriculture adapted to a changing world.

One such effort has come from the Land Institute, an organization in Kansas that works on natural systems agriculture, which seeks to retain the ecological stability of the prairie with its perennial seed plants along with a grain and seed yield comparable to that from annual crops.

After four decades of effort, the institute has introduced its first commercial grain, a trademarked variety called Kernza.  Kernza is a domesticated perennial wild grass – a so-called intermediate wheatgrass – that has a long, slender head that resembles wheat seeds.  People describe its taste as sweet and nutty.   Kernza is already being made into a cereal called Honey Toasted Kernza by Cascadian Farms.  Patagonia Provisions – a spin-off from the clothing company – is making beer from the new grain.

Although Kernza is already being grown and sold commercially, it is not yet ready for prime time.  Last year, there were only about 1,000 acres in cultivation and the yield is only a third to a tenth of the yield of wheat. 

Developing a sustainable perennial polyculture of edible plants would have major benefits such as not having to plow every year, plants developing large root systems that can reach water far beneath the surface and, without annual plowing, having soil carbon remain in the ground.

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With New Perennial Grain, a Step Forward for Eco-Friendly Agriculture

Photo courtesy of Cascadian Farms/General Mills.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Global Fisheries

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A Rutgers University-led study published in the journal Science has shown that climate change has taken a toll on many of the world’s fisheries and that over fishing has magnified the problem.

Seafood has become an increasingly important source of nourishment as the global population grows, especially in coastal, developing countries where it provides as much as half of the animal protein eaten.  More than 50 million people worldwide work in the fisheries industry or subsist on fisheries.

Scientists at Rutgers and the National Oceanic and Atmospheric Administration studied the impact of ocean warming on 235 populations of 124 species in 38 ecological regions around the world.  Species included fish, crustaceans such as shrimp, and mollusks such as scallops.  They combined data on fisheries with ocean temperature maps to estimate temperature-driven changes in the sustainable catch over 8 decades.  The data covered about one-third of the global catch.

According to the study, ocean warming has led to an estimated 4.1% drop in sustainable catches, on average around the world, for many species of fish and shellfish from 1930 to 2010.  In five regions that include the East China Sea and the North Sea, the estimated decline was 15 to 35%.

The researchers recommend that fisheries managers eliminate over fishing, rebuild fisheries, and account for climate change in fisheries management decisions.  Over fishing provides a one-two punch to fisheries facing warming waters.   It not only makes fisheries more vulnerable to ocean warming but continued warming will also hinder efforts to rebuild over fished populations.

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Climate Change Shrinks Many Fisheries Globally, Rutgers-Led Study Finds

Photo, posted April 23, 2011, courtesy of Derek Keats via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Infertility

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Many of us are all too familiar with the effects of climate change.  Our changing climate, as a result of our actions, is leading to rising global temperatures, biodiversity loss, ocean acidification, wildfires, more weather extremes like floods and droughts. But a lesser known effect of climate change could lead to frightening consequences: infertility.

According to researchers at the University of Liverpool, rising temperatures could make some species sterile and lead them to succumb to the effects of climate change far earlier than currently thought. Their work was recently published in the journal Trends in Ecology and Evolution, and it was produced in collaboration with scientists from the University of Leeds, University of Melbourne, and Stockholm University.

Biologists and conservationists are trying to predict where species will be lost due to climate change so that suitable reserves can be established in other locations.  But the problem is that most data on when temperature will make an area unlivable for a species is based on its ‘critical thermal limit’ or CTL.  This is the temperature at which a species would collapse, stop moving, or die. 

The authors of the article fear that the impact of climate change on species survival is being underestimated.  Because rather than zeroing in on lethal temperatures, the scientists argue the focus should be on the temperatures at which organisms can no longer breed.  Extensive plant and animal data suggest organisms lose fertility at a lower temperature than their CTL.

The scientists have proposed a new fertility-based metric to gauge how organisms function as temperatures climb: Thermal Fertility Limit or TFL.  Understanding when a species will cease to reproduce will certainly help conservation measures. 

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Climate change and infertility — a ticking time bomb?

Photo, posted August 11, 2013, courtesy of Mike Lewinski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Hippo Waste And Fish

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Agricultural and sewage pollution can cause low-oxygen conditions and fish kills in rivers. A new study published in Nature Communications reports that hippo waste can have a similar effect in Africa’s Mara River, which passes through the world renowned Maasai Mara National Reserve of Kenya and is home to more than 4,000 hippos.

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The Ecology Of Dust

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It isn’t something we think about very often, but dust is a connector of ecosystems around the world.  Dust carries various minerals and nutrients to places where such things are in very scarce supply.  This includes the oceans of the world as well as many forests and other ecosystems.  For example, phosphorus-bearing dust carried from the Gobi Desert is essential to the growth of giant redwoods in California’s Sierra Mountains.

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Disappearing Kelp Forests

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In recent decades, ocean temperatures in many places have warmed by nearly 3 degrees Fahrenheit.  An effect of this warmer water is the decimation of what were once luxuriant giant kelp forests in eastern Australia and Tasmania.  There used to be thick canopies covering much of the region’s coastal sea surface, but they have wilted in the intolerably warm and nutrient-poor water.

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Learning From Fire

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The Tubbs Fire was the huge wildfire that burned parts of Napa, Sonoma and Lake counties in Northern California in October.  Between that fire and several smaller ones going on at the same time, at least 43 people died and over 8,400 homes and buildings were destroyed.  The Tubbs Fire alone burned over 36,000 acres. The even larger December wildfires in Southern California scorched hundreds of thousands of acres in multiple counties.

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Did People Create The Sahara Desert?

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One of the arguments some people make when discussing human causes of climate change is that people can’t cause such massive changes.  However, there is a long historical record of human-driven ecological and climatic change in Europe, North America and New Zealand, among other places.

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The Great Salt Lake Is Shrinking

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Utah’s Great Salt Lake is the largest salt water lake in the Western Hemisphere and is the largest body of water in the United States after the five Great Lakes.  When the pioneers first arrived in the area back in the middle of the 19th century, the lake spread across about 1,600 square miles.   Now, the lake covers an area of only about 1,050 square miles, a reduction of about 35%.

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Lessons From The Forest

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For more than half a century, scientists have converged on Hubbard Brook Experimental Forest in New Hampshire’s White Mountains to explore how forest ecosystems work.  The site was established by the U.S. Forest Service to study the relationship between forests and New England’s water supply. In the 1960s, inquiry was expanded to include ecology, biogeochemistry, and studies of birds and other animals.

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