Five Questions for Elizabeth Kolbert
On Facing Up to the Sixth Extinction
Elizabeth Kolbert's new book, The Sixth Extinction
, focuses on one of the most troubling realities of our age:
We are living in a period when, for only the sixth time in earth’s history, the diversity of species is contracting suddenly and rapidly — but now, we humans are the cause. For her reporting, Kolbert, an e360 contributor
and New Yorker
staff writer, traveled from the Peruvian Andes to Australia's Great Barrier Reef, probing the fate of a dozen species. Yale Environment 360
asked Kolbert five questions about the book and what she discovered in researching it.
10 Feb 2014:
New Plant Found in Andes
Supports up to 50 Species, Researchers Say
Researchers working in the Ecuadorian Andes have discovered a new species of black pepper plant
that is a nexus of biodiversity. The plant, named Piper kelleyi
, supports roughly 40 to 50 insect species, the scientists estimate, many of which are entirely dependent on the
Specialist herbivore Eios feeds on P. kelleyi
plant for survival. P. kelleyi
produces chemical compounds that are known to deter most herbivores, but a single type of caterpillar has adapted to overcome the toxicity of the plant's defenses. That caterpillar, in turn, is preyed upon by species of wasps and flies dependent on that specific caterpillar species — and ultimately the plant — for survival. Altogether, an assemblage of up to 50 species of herbivorous and predatory insects are dependent on P. kelleyi
, the researchers report in the journal PhytoKeys
07 Feb 2014:
Documented in Remote Forest in Congo
Researchers have documented a huge population of chimpanzees in the Democratic Republic of Congo — a community of perhaps tens of thousands of individuals with its own unique customs and behaviors, the Guardian reports
. The so-called "mega-culture," which spans 50,000 square kilometers of virtually untouched
Chimps are thriving in a remote Congo forest.
forest, is thought to be the largest population of chimps in Africa and one of the last remaining continuous populations of chimpanzees in the wild, the scientists report
in the journal Biological Conservation
. The researchers first reported on this community in 2007, but their new survey includes detailed videos of the thriving population and its unique behaviors, which include feasting on leopards, using tools to harvest giant African snails and swarming insects, and building ground nests far more frequently than other chimps. While the find is heartening in terms of chimpanzee conservation, the researchers and wildlife advocates fear the population could be decimated by habitat loss and poachers, who stand to make huge profits in the bushmeat trade.
06 Feb 2014:
Maps Show Tropical Corridors
Important to Wildlife As Climate Changes
A new set of maps
highlights the importance of habitat corridors in helping wildlife deal with the effects of climate change and deforestation. The series of maps shows more than 16,000 habitat corridors
— swaths of
land that connect forests or protected areas and allow animals to move between them — in tropical regions of Africa, Southeast Asia, and South America. High-resolution data on biodiversity, endemism, and vegetation density allowed the researchers, led by Patrick Jantz of the Woods Hole Research Center, to determine which corridors are most important for maintaining biodiversity under changing climate conditions. The maps also highlight which corridors are most important for sequestering carbon and averting carbon emissions associated with deforestation. Researchers hope the findings will help guide wildlife protection plans and serve as a framework prioritizing the conservation of habitat corridors.
28 Jan 2014:
Peru Park Holds Record
Reptile and Amphibian Diversity, Study Finds
A new study crowns Peru's Manu National Park
as the place with the world's most diverse collection of reptiles and amphibians — 287 species in all. The park's 155 amphibian and 132 reptile species outnumber those in Ecuador's Yasuní National Park
, which, with 271 reptile
A glass frog from Manu's cloud forests
and amphibian species, was previously believed to contain the world's most diverse collection of reptiles and amphibians. Although Manu National Park represents only 0.01 percent of the world's land area, it houses 2.2 percent of all amphibian species and 1.5 percent of all reptile species, the researchers note. They attribute the rich diversity to the park's elevation gradient, which spans the Western Amazon's tropical rainforest up through high Andean cloud forests, providing a wide range of habitats. Manu also has record bird diversity — with 1,000 species, or 10 percent of the world's total species — and tremendous butterfly diversity, with 1,200 species. Scientists say the inventory of the national park's richness is far from complete. DNA analyses, frog call studies, and other techniques will likely reveal even more diversity, the authors note in the journal Biota Neotropica
Interview: How Citizen Science Is
Aiding and Democratizing Research
When biologist Caren Cooper
carries out her avian studies, she’s aided by thousands of assistants, none of whom are paid for their work. That’s because Cooper, a research associate at the Cornell Lab of Ornithology
, relies on the help of so-called citizen scientists, volunteers from across the country who contribute data
to her research projects. These lay people provide information that enables her and other scientists to study bird life in ways that would otherwise be impossible. But, as Cooper notes in an interview with Yale Environment 360
, the uses of citizen science go well beyond bird research. Bushmen in the Kalahari are using apps to document wildlife and natural resources that need to be protected. Environmental activists also are employing open-source technology to measure and monitor pollution, including the deployment of kites and balloons to document such events as the Deepwater Horizon oil spill. “A lot of the ways for us to move forward in certain fields require massive collaboration,” says Cooper. “And so we’re building all the infrastructure for these collaborations, all of the web tools — whatever we need to make that happen.”
Read the interview.
22 Jan 2014:
New Virus Associated With
Massive Bee Die-Offs, Researchers Report
A rapidly mutating virus may be partially responsible for the massive bee die-offs known as colony collapse disorder (CCD), which has wiped out a third of commercial bee colonies annually for the past seven years, a group of U.S. and Chinese researchers reports
. Most scientists, including the study's authors, believe CCD is triggered when colonies are weakened by a combination of factors
, such as viruses, parasites, and perhaps pesticides. The study, published
in the journal mBio
, found in bees a variant of the tobacco ringspot virus, an RNA virus that likely jumped from tobacco plants, to soy plants, to bees. Weak bee colonies began succumbing to massive die-offs in autumn, and the researchers found those bees were heavily infected with tobacco ringspot — which is believed to affect honeybees' nervous systems — and other viruses. Strong colonies that made it through the winter showed no evidence of infection by tobacco ringspot. The researchers believe the virus jumped from plants to bees through "bee bread," a concoction of pollen, nectar, and saliva they feed their larvae. Bee infection by tobacco ringspot is the first known instance of a virus from pollen jumping to bees.
20 Jan 2014:
Soil Microbes Can Alter DNA
In Response to Climate Change, Study Says
A 10-year study of soil ecosystems
has determined that microbes alter their genetic code in response to a warming climate so they can process excess carbon being absorbed by plants from the atmosphere, a team of U.S. researchers reports in the journal Applied and Environmental Microbiology
. A 2-degree Celsius temperature increase spurred microbes in soil ecosystems to, over many generations, tweak their DNA, amping up their respiratory systems and converting extra organic carbon in the soil to CO2. The soil contained extra carbon because the 2-degree temperature increase made plants grow faster and higher; when those plants began to die, the carbon in their leaves, stems, and roots was added to the soil and taken up by the microbial community. Understanding the "black box" of carbon's fate in soil ecosystems holds important clues for better forecasting an ecosystem's response to climate change, says Georgia Institute of Technology researcher Kostas Konstantinidis, an author of the study. "One reason that models of climate change have such big room for variation is because we don’t understand the microbial activities that control carbon in the soil," he said.
17 Jan 2014:
More Than 1,000 Rhinos
Poached in 2013, South African Officials Say
More than 1,000 rhinos were illegally killed in South Africa last year, a record total and an increase of more than 50 percent from 2012, South African officials say
. South Africa is home to nearly all of the
world's 20,000 rhinos, which are targeted by poachers
because their horns are highly valued and believed to contain medicinal properties. Although those claims are scientifically unfounded, demand from increasingly wealthy consumers in China and Vietnam has driven the price of rhino horns to over $65,000 per kilogram — more valuable than gold, platinum, or cocaine. South Africa has tried to stem the crisis by training park rangers to use arms, drones, and helicopters
, but those anti-poaching efforts have shown limited success. Rhino poachings in 2012 also increased by 50 percent over 2011 totals, and 37 have been poached so far in 2014, officials report. Most of the killings are taking place in South Africa's Kruger National Park, where 606 rhinos were killed last year and 425 in 2012.
16 Jan 2014:
Pebble Mine Would Endanger
Alaska's Bristol Bay, Major EPA Study Finds
A three-year study by the U.S. Environmental Protection Agency (EPA) has determined that mining in Alaska's Bristol Bay area would pose significant dangers to the environment
, a potentially fatal setback for plans
Mulchatna River, part of Bristol Bay watershed
to develop Pebble Mine, a major open-pit mining project that aimed to exploit one of the largest and richest mineral deposits in the world. The EPA study cited concerns for the region's thriving sockeye salmon population
and its native people, saying the mine would destroy 24 to 94 miles of salmon streams and 1,300 to 5,350 acres of wetlands, ponds, and lakes. Pebble Mine proponents, including Alaska Governor Sean Parnell, criticize the study as flawed and rushed, since the development company wasn't allowed to submit its mining plan before the EPA study. Native groups, fishermen, and environmental organizations are applauding the study. The proposed mine — which seeks to exploit gold, copper, and other metals — was already in trouble, with one of two major partners withdrawing from the project last year.
15 Jan 2014:
West African Lions Are
Critically Close to Extinction, Study Says
West African lions are close to extinction, and vulnerable populations could be wiped out in the next five to 10 years, according to new research
led by the wild cat conservation group Panthera. West African lions, which are genetically distinct from other African lions, once numbered in the tens of thousands. Now the
Male West African lion
population has been reduced to around 400 individuals spread across 17 countries, largely due to habitat loss, a shortage of prey, and poaching, according to the study published in PLOS ONE
. Of the remaining lions, only about 250 are mature enough to reproduce, but in many cases those individuals are spread too far apart to breed. West African lions are now present in only 1.1 percent of their original habitat and should be considered "critically endangered," according to the study. Running low on habitat and prey, the lions sometimes kill livestock. Villagers then kill the lions in revenge. "It's become very complicated for this carnivore at the top of the food chain to find enough space and food to survive," one scientist told Reuters.
09 Jan 2014:
Faced With Sea Ice Loss,
Emperor Penguins Alter Breeding Tactics
Confronted with the loss of sea ice in some parts of Antarctica, four colonies of emperor penguins have come up with an innovative breeding strategy
to adapt to their changing environment. Using satellite images,
an international team of scientists tracked the four colonies from 2008 to 2012. In the first three years, the emperor penguins hatched and incubated eggs in their customary fashion — atop the sea ice that freezes during the Antarctic winter and spring. But in 2011 and 2012, sea ice did not form until a month after the breeding season began. As a result, the emperor penguins, which are the largest penguin species on earth, did something never before witnessed by scientists: They climbed the nearly sheer walls of large, floating ice shelves — huge structures, often hundreds of square miles in extent, that flow from land-based glaciers into the sea. In the region of the four colonies, the ice shelf walls reach as high as 100 feet. The scientists say the altered breeding behavior could demonstrate how ice-dependent emperor penguins may adapt to a warming world.
06 Jan 2014:
China Crushes Six Tons
Of Ivory to Stem Elephant Poaching
In an effort to stem elephant poaching, Chinese authorities have crushed six tons of confiscated ivory
, the first such effort in the country's history. Coordinated by the State Forestry Administration and the General Administration of Customs, the event was widely publicized and aimed at spreading awareness in China of the scale of the global poaching crisis. Conservation
groups consistently name China as a major driver of elephant poaching, as the country's growing middle class has increasingly sought to buy ivory ornaments and ivory-based medicinal therapies, which have no scientific or medical basis. The six tons of ornaments and tusks that were crushed represent only a fraction of China's ivory stockpile, which is probably more than 45 tons, the Wildlife Conservation Society (WCS) estimates. Still, many conservation groups are applauding China's efforts. "This destruction of ivory by China is a symbol of the government's growing responsiveness to the ivory crisis," the WCS said.
31 Dec 2013:
Atlantic Ocean Zooplankton
Are Now Reproducing in Arctic Waters
For the first time, scientists have discovered species of Atlantic Ocean zooplankton reproducing in Arctic waters
. German researchers say the discovery indicates a possible shift in the Arctic zooplankton community as
The amphipod Themisto compressa
the region warms, one that could be detrimental to Arctic birds, fish, and marine mammals. Studying traps that have been suspended for 13 years in the Fram Strait, scientists from the Alfred Wegener Institute found that small species of crustaceans common to the Atlantic are increasingly moving into Arctic waters. The researchers found fertile females as well as individuals at all stages of development, showing that the Atlantic species is reproducing in the frigid waters. The one-centimeter amphipods are smaller than respective Arctic species, meaning that the spread of the Atlantic crustaceans northward could reduce the volume of food available to Arctic predators. The research was published in the journal Marine Ecology Progress Series
Photo Essay: Documenting the Swift
Change Wrought by Global Warming
For 25 years, photographer Peter Essick has traveled the world for National Geographic
magazine, with many of his recent assignments focusing on the causes and consequences of climate change. In a Yale Environment 360
photo essay, we present a gallery of images he took while on assignment in Antarctica, Greenland, and other far-flung locales affected by climate change. View the photo gallery.
09 Dec 2013:
Intensifying Storms Are
Contributing To Ongoing U.S. Wetlands Loss
The U.S. is losing wetlands at a rate of 80,000 acres per year, in part because of intensifying coastal storms and sea level rise, according to a new government study
. From 2004 to 2009, the country lost more than 360,000 acres of freshwater and saltwater wetlands, a decline driven both by traditional factors, such as coastal development, as well as worsening storms and slowly rising seas, the study says. The rate of loss is a signal that government efforts to protect and restore wetlands are failing to keep pace with major environmental changes, experts told The Washington Post
. The most pronounced wetlands losses were along the Gulf of Mexico, where major hurricanes have wreaked havoc on coastal lands. Along the Atlantic coast, a rapid increase in coastal development is funneling stormwater runoff into wetlands that cannot handle it, the study said. The loss rate of 80,000 acres annually represents a 25 percent increase over the rate of wetlands loss during 1998-2004, the last time government agencies examined the problem.
03 Dec 2013:
Microplastic Pollution Harms
Worms at Bottom of Food Chain, Study Finds
As plastic trash accumulates in ocean ecosystems, it may be damaging worms and other sensitive marine life at the bottom of the food chain, scientists report. Two British studies found
that microplastics — tiny remnants, less than 5 mm in diameter, from the breakdown of plastic trash — made seafloor worms eat
Beach sediments churned by a lugworm
less and transferred pollutants from the plastics to the worms. Because they ate less, the worms had less energy to invest in important functions
such as growth, reproduction, and churning sediments, one of their most important roles in the ocean ecosystem. The worms also absorbed harmful chemicals from the debris
, including hydrocarbons, antimicrobials, and flame retardants, researchers said. Lugworms, often called the "earthworms of the sea," are considered an indicator species because they feed on ocean floor sediments. Microplastics have been accumulating in those sediments since the 1960s, and, although each particle is nearly invisible, taken together microplastics are the most abundant form of solid-waste pollution on the planet.
02 Dec 2013:
Poachers Killed 22,000
Elephants in Africa Last Year, Group Says
Poachers slaughtered 22,000 elephants in 27 African countries last year, according to a new report
. Officials with The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and two conservation groups said that 15,000 elephant
Rhett A. Butler/Mongabay
A herd in Namibia
deaths from poaching were officially reported in Africa and that another 7,000 deaths went unreported. Although that number is a slight decrease from the 2011 estimate of 25,000 poaching deaths, CITES officials warn that poaching rates are far too high and could soon lead to local extinctions. Africa, which is currently home to roughly 500,000 elephants, could lose a fifth of its elephant population over the next 10 years, CITES says. "The estimated poaching rate of 7.4 percent in 2012 remains at an unsustainably high level, as it exceeds natural population growth rates (usually no more than 5 percent)," the report says.
29 Nov 2013:
Wide Mangrove Destruction
Is Documented Along Coast of Myanmar
Rapid agricultural expansion destroyed nearly two-thirds of the mangrove forests
in Myanmar’s Ayeyarwady Delta between 1978 and 2011, increasing the region’s vulnerability to cyclones and typhoons, according to a new study. Using remote sensing imagery
and field data, researchers from Myanmar and Singapore said that the dense mangrove cover in the Ayeyarwady Delta declined from 2,623 square kilometers to 1,000 square kilometers in that 33-year period. The main cause was agriculture expansion and the researchers said that if rates of destruction continue at their current pace the delta’s mangroves could be completely deforested by 2026. Reporting in the journal Global Environmental Change
, the scientists said the loss of mangroves in the Ayeyarwady Delta could put the region at greater risk of major storms such as Cyclone Nargis, which killed 138,000 people in Myanmar in 2008. But the researchers said the destruction could be slowed if Myanmar creates coastal protected areas.
26 Nov 2013:
Updated Conservation List
Finds Forest Giraffes on Brink of Extinction
In an updated list released today, the International Union for the Conservation of Nature (IUCN) noted some significant successes and failures in global wildlife
Okapi, or forest giraffe
conservation efforts. A major success story is the leatherback sea turtle
, whose Atlantic population has recovered enough for the species to be considered only vulnerable, rather than critically endangered. The IUCN attributed the leatherback rebound to better protection of nesting beaches and reduced fisheries bycatch. The updated Red List contains more somber news, though, for the blue-tongued forest giraffe
, the national symbol of the Democratic Republic of the Congo. The striped-legged forest giraffe, a species of okapi, is on the brink of extinction due mainly to the long, ongoing civil war in that country, which has led to increased poaching and loss of habitat. The Red List's ranks of threatened species have grown by 352 species since this summer
, Mongabay reports, with roughly 21,000 species now listed as threatened.
Fish 2.0: A Contest Seeks to Foster
A More Sustainable Seafood Industry
Twenty pioneers in the sustainable seafood business climbed a stage at Stanford University in November in an effort to woo the judges at the Fish 2.0 contest
Click to Enlarge
HM Terry Co.
The winning project connects fishermen directly to customers.
with proposals on how to change the way the U.S. catches, distributes, and markets fish. A business competition at heart, Fish 2.0 brought together entrepreneurs and investors to spur innovation in the tradition-bound seafood industry. Competitors's proposals ranged from converting waste at fish processing plants to expanding a Hawaiian network of aquaponic growers, who raise fish and vegetables together in tanks, into the developing world. One proposal aimed to create a data system to track catches in real time, enabling fisheries managers to hold the line on harvests. Contestants headed home with more than $75,000 in prize money. Read more.
19 Nov 2013:
Pollution From Plastic Trash
May Make Tiny Island a Superfund Site
The U.S. Environmental Protection Agency plans to study whether plastic pollution on a small island in the Pacific Ocean is severe enough to warrant listing it as a Superfund clean-up site
. Tern Island, a 25-acre strip of land about 500 miles northwest of the Hawaiian island
Oahu, is home to millions of seabirds, sea turtles, and the endangered Hawaiian monk seal. The U.S.-based Center for Biological Diversity asked the EPA to add the entire Northwestern Hawaiian Islands and parts of the so-called Great Pacific Garbage Patch
to the list of federal Superfund sites due to extreme marine debris pollution, but the agency has only agreed to undertake an environmental study on Tern Island. The island is awash with debris ranging from plastic water bottles and bits of plastic to discarded fishing gear and home appliances. Studies have shown the trash can take a heavy toll on wildlife — seabirds, for example, often ingest bits of plastic after mistaking them for food and eventually die of starvation. The EPA study is the first step of a potentially years-long process to determine if the island qualifies for listing under the 1980 Superfund law.
14 Nov 2013:
U.S. Crushes Six Tons
Of Illegally Trafficked Elephant Ivory
The U.S. Fish and Wildlife Service
(FWS) destroyed six tons of elephant ivory
today that field agents seized over the past 25 years. The U.S. Ivory Crush event, which took place in Denver, Colorado, marked the first time
the FWS has destroyed large quantities of ivory. The move was an attempt to send a clear message that the U.S. will not tolerate illegal ivory trafficking and the toll it's taking on elephant populations in Africa and Asia, the FWS said. Seized ivory is usually kept as evidence for prosecuting traffickers, then later used for education and training, but the FWS had accumulated far more ivory than it needs. The ivory that was crushed included full tusks, carved tusks, jewelry, carvings, and other objects, and came from at least 2,000 poached elephants, the FWS estimates.
13 Nov 2013:
Plastic Debris in Ocean
Has Spawned a 'Plastisphere' of Organisms
The plastic debris that litters the world's oceans has developed its own unique and diverse microbial ecosystem, researchers report. The microscopic community, which scientists dubbed the "plastisphere,"
includes more than 1,000 species of algae, bacteria, microscopic plants, symbiotic microbes, and possibly even pathogens, the researchers say in Environmental Science & Technology
. Some of the plastisphere microbes, many of which had never before been documented, contain genes that could help break down hydrocarbons, indicating the microbes may play a role in degrading the debris, the research shows. Plastic trash is the most abundant type of debris in the ocean, inflicting harm on fish, birds, and marine mammals that are entangled by it or ingest it. Until now, researchers hadn't looked at microbes living on the debris, which make up a sort of artificial "microbial reef," one of the scientists said
Interview: Using Robots to Unlock
Mysteries of CO2 and the Oceans
As climate change accelerates, scientists are focusing on the key role the world’s oceans play in absorbing half the planet’s carbon dioxide. But the precise mechanisms
Robotic Wave Glider
by which the oceans remove carbon from the atmosphere and the consequences for marine life remain poorly understood. That has led Tracy Villareal, a professor of marine science at the University of Texas at Austin, to devote his research to diatom phytoplankton. To better understand how these tiny organisms mitigate climate change, Villareal has become a pioneer in the use of a wave- and solar-powered ocean-going robot, known as the Wave Glider. In an interview with Yale Environment 360
, Villareal discusses why unlocking the secrets of diatoms is critical to understanding climate change and how deploying robots will revolutionize marine science. “There are all sorts of wild robotic systems under development,” he says. Read the interview.
06 Nov 2013:
Disturbed Tropical Forests
Are Slow to Regain Plant Biodiversity
In tropical forests that are regrowing after major disturbances, the ability to store carbon recovers more quickly than plant biodiversity, researchers from the U.K. have found
. However, even after 80 years, recovering forests store less carbon than old-growth
A regrowing tropical forest in Brazil
forests, according to a study published in the Proceedings of the Royal Society B.
This is likely because regenerating forests are often dominated by small, fast-growing trees and it may take centuries for larger trees, which hold more carbon, to become established, according to scientists from the Center for Ecology & Hydrology and Bournemouth University, who studied more than 600 recovering tropical forests. Tree species that are hallmarks of old-growth forests were rare or missing in the regrowing forests, the study showed. Since regenerating forests are often located far from old-growth forests and surrounded by farmland, it may be difficult for animals to move seeds between the forests, which may account for the lower plant biodiversity, researchers said.
23 Oct 2013:
Endangered Asiatic Cheetahs
Are Spotted by Iranian Conservationists
Iranian conservationists have spotted a rare Asiatic cheetah with four cubs, offering hope that the large cats can be pulled back from the brink of extinction. Only 40 to 70 Asiatic cheetahs exist today, all in Iran. Over the
weekend, conservationists with the Persian Wildlife Heritage Foundation (PWHF) spotted the five cheetahs in Khar Turan national park in northern Iran. "In the past year or so that we closely monitored Turan, we never spotted a family, especially female cheetahs with cubs," Delaram Ashayeri, project manager at PWHF, told the Guardian
. "It shows Asiatic cheetahs are surviving, breeding cubs are managing to continue life. It's good news against a barrage of bad news about these animals." Iranian conservationists have been involved in a decade-long campaign to protect the cheetahs and educate indigenous people living near them. But sanctions imposed by Western nations over Iran's nuclear program have hampered these efforts, making it difficult to secure international funding and equipment, such as camera traps.
17 Oct 2013:
Animals May Play Significant
Role in Carbon Cycling, Researchers Say
Wildlife may play a more important role in the global carbon cycle than researchers have previously given it credit for, according to a study
from an international group of scientists. Although models generally include
Muskoxen in Alaska
carbon cycling by plants and microbes, they often ignore the ways animals contribute to the process. That's a mistake, says Oswald Schmitz, an ecologist at Yale who led the study, because the actions of wildlife can affect carbon cycling through "indirect multiplier effects." For example, the massive loss of trees in North America triggered by the pine beetle outbreak has caused a net carbon change on scale with British Columbia's current fossil fuel emissions, the researchers reported in Ecosystems
. And in the Arctic, where about 500 gigatons of carbon is stored in permafrost, large grazing mammals like caribou and muskoxen can help maintain the grasslands that have a high albedo and thus reflect more solar energy. "We're not saying that managing animals will offset these carbon emissions," Schmitz said. "What we're trying to say is the numbers are of a scale where it is worthwhile to start thinking about how animals could be managed to accomplish that."
11 Oct 2013:
Agricultural Ammonia Emissions
Threatening U.S. National Parks, Study Finds
Ammonia emissions from agricultural fertilizers are threatening sensitive ecosystems in U.S. national parks, a study led by Harvard researchers
has found. Thirty-eight national parks are seeing nitrogen deposition levels at or above the threshold for ecological damage,
Great Smoky Mountains N.P.
the study says. In natural ecosystems, excess nitrogen can disrupt nutrient cycling in soil
, cause algal overgrowth, and make aquatic environments acidic. While some of that nitrogen comes in the form of nitrogen oxides (NOx) from power plants and vehicle exhaust, existing air quality regulations and new clean energy technologies are helping reduce NOx emissions. Ammonia emissions from agricultural operations, however, are expected to climb as demand for food and biofuels surges. Daniel Jacob, who led the study, said that because ammonia is volatile, only 10 percent of the nitrogen makes it into the food, with much of it escaping through the atmosphere and being deposited across the landscape. According to the report, published in Atmospheric Chemistry and Physics
, hardwood trees, such as those shown above, are most sensitive to excess nitrogen in eastern temperate forests, while in western national parks lichens appear to suffer first.
07 Oct 2013:
Nutrient Recycling by Sponges
Is Vital in Sustaining Reefs, Study Says
Sponges are the unsung heroes of coral reefs, helping the vibrant ecosystems thrive in the marine equivalent of a desert, a Dutch team working in the Caribbean has found
. Scientists had long questioned how reefs, some
of the most productive communities on earth, were able to survive in low-nutrient tropical seas. Bacteria help recycle some nutrients, but the so-called "microbial loop" can't account for the high rates of carbon, nitrogen, and phosphorous recycling needed to maintain a coral reef, researchers say. Sponges fill that void by drawing in plankton and organic matter expelled by the corals and shedding cells that other reef organisms ingest as food, the researchers report in Science
. The "sponge loop," as the Dutch team calls the process, recycles 10 times more organic material than bacteria do and produces as many nutrients as all other primary producers in a coral reef combined, they say.