14 Apr 2016:
Drought, Climate Change
Cause Rapid Plant Evolution in California
As climate change alters ecosystems and weather patterns, species across the globe are undergoing change as well. Some are dwindling in numbers and others are going extinct, but many are adapting.
The Brassica rapa plant.
A team of U.S. researchers, led by biologist Steven Franks of Fordham University, found the drought that impacted California between 1997 and 2004 changed the Brassica rapa plant
, a type of field mustard, down to the genetic level. After seven years of water scarcity, the plants had shifted their flowering times forward by weeks to take advantage of early season rain. “This research shows us that contrary to the previous belief… evolutionary changes can happen extremely rapidly,” Franks wrote in the Huffington Post
. “However, this does not mean that we don’t need to worry about climate change because species will just evolve. A recent analysis concluded that 1 in 6 species could face extinction if climate change continues unabated.”
12 Apr 2016:
Scientists Reimagine The
Tree of Life With New Microbe Knowledge
Following years of intense exploration and research into the microbial world, scientists have reimagined the tree of life
—the iconic visual representation of the living world first proposed by Charles Darwin in 1859.
The new tree of life.
The project was led by researchers at the University of California, Berkeley, who over the last decade have been gathering DNA from across the globe—from everywhere from meadow soils and river mud to deep sea vents—to reconstruct genomes and describe thousands of new microbial species. Curious how their findings fit into the tree of life, the scientists used a supercomputer
to visualize how more than 3,000 new and known species related to one another. They discovered that eukaryotes, the group that includes humans, exist on a thin twig compared to the microbial branch of the tree. “The tree of life as we know it has dramatically expanded due to new genomic sampling of previously enigmatic or unknown microbial lineages,” the authors wrote
11 Apr 2016:
More Than 50 Percent of
Great Barrier Reef Affected By Bleaching
Record high ocean temperatures in the western Pacific have caused more than half of the Great Barrier Reef to undergo a mass coral bleaching event this year, according to a team of Australian scientists
conducting aerial surveys.
ARC Coral Reef Studies
An aerial shot of the Great Barrier Reef in early April.
Corals thrive in a narrow temperature range, and when waters warm above normal—as they have this year from climate change and a strong El Nino—the organisms expel their symbiotic algae, leaving them without a source of food and susceptible to disease. Scientists’ next step is studying the corals up close to determine how deep the bleaching is, said
Terry Hughes, a marine biologist at James Cook University and head of the Australian coral bleaching task force. “If the corals are severely bleached, then a lot will die,” Hughes said. “If they are lightly bleached, which is the case with a lot of reefs south of Townsville, then they’ll regain their color over the next couple of months and there won’t be much mortality.”
07 Apr 2016:
How Ancient Algae Could
Help Cure Brain and Breast Cancer
One of the oldest life forms on earth may hold the key to battling hard-to-treat cancers, according to new research
by scientists at Oregon State University. The compound, coibamide A, is found in blue-green algae, organisms that have existed for at least two billion years. It was found during a diving trip in Panama’s Coiba National Park eight years ago and run through the National Cancer Institute’s database of potential anti-cancer compounds. Coibamide A was tested on mice and found to be more effective at killing brain and triple negative breast cancer cells—two of the most aggressive and hard-to-treat types of the disease—than anything ever tested before. "The chemical diversity found in nature has always been a significant source of inspiration for drug design and development, but… marine environments remain relatively unexplored," said Jane Ishmael, a cellular biologist at Oregon State University and lead author of the new study.
06 Apr 2016:
Half of World Heritage Sites Are
Threatened By Industrial Development
Since 1972, the United Nations has worked to protect 229 locations in 96 countries known for their “exceptional natural beauty” and “cultural significance.” These spots, known as World Heritage Sites,
The Great Barrier Reef
range from Mount Kilimanjaro in Tanzania to the Great Barrier Reef in Australia, China’s panda sanctuaries, and the Grand Canyon in the United States. A new survey by the World Wildlife Fund, however, has found half of these sites are under threat
from oil and gas development, mining, illegal logging, overfishing, or other industrial activities. Eleven million people live in or near these sites, the report says, and depend on them for their housing, food, water, jobs, or ecosystem services like flood protection and CO2 sequestration. “We are not going to develop a just and prosperous future, nor defeat poverty and improve health, in a weakened or destroyed natural environment,” the authors wrote.
05 Apr 2016:
El Nino Prevents Phytoplankton
Growth, Endangering Marine Food Web
El Nino—the cyclical warming of the Pacific Ocean—has wreaked havoc on the world’s weather
for the past two years, from a record-breaking number of cyclones in the North Pacific to flooding in South America.
Satellite images of phytoplankton growth.
But scientists at NASA recently discovered
that the climate phenomenon also has a big impact on phytoplankton, the tiny oceanic organisms that serve as the base of the marine food chain. Normally, ocean currents drive cold, deep water to the surface near the equator, bringing with it a flood of nutrients that feed phytoplankton. El Nino’s mass of warm water stops this upwelling. The result is a marked drop in phytoplankton levels. “This decline echoes through many species,” said Stephanie Uz, an ocean scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland who led the study. “Small fish that feed on phytoplankton starve. This affects everything from penguin and iguana populations in the Galapagos to governments managing fisheries.”
04 Apr 2016:
As Habitat Loss Slows Down,
Tigers Could Double In Number By 2022
With populations hovering at less than 3,500 worldwide, tigers have long been considered on the brink of extinction. But scientists finally have good news:
Habitat loss has slowed down more than expected in recent years due to conservation efforts, and there is now enough forest for tigers to double in number by 2022. According to a new study in the journal Science Advances
, less than 8 percent of global tiger habitat disappeared between 2001 and 2014, 98 percent of which happened in Indonesia and Malaysia due to the booming palm oil industry. “It is not a sign that we are in the clear yet, but it does show us that tigers can potentially recover from the edge of extinction if we make the right forest management choices,” said Anup Joshi, a conservation biologist at the University of Minnesota and lead author. Tiger populations in Nepal and India, for example, have increased 61 and 31 percent, respectively.
01 Apr 2016:
Scientists Study the Skies
To Create a Map of the World’s Biomes
Curious where certain species live? Don’t look down. Rather, study the skies, according to new research published in the journal PLoS Biology
. Scientists from the University of Buffalo and Yale University
used images from NASA satellites to build a database of cloud cover for every square kilometer of the planet from 2000 to 2014. They then used the information to map the world’s biomes. They found that cloud patterns are a much more accurate way of predicting species distribution than using extrapolated on-the-ground observations, the method most conservationists use today. “Sunlight drives almost every aspect of ecology,” Adam Wilson, an ecologist at the University of Buffalo who led the study, told New Scientist
. “So when you put something in between the sun and plants, that is going to have implications on the amount of energy they are receiving, soil moisture, leaf wetness, and humidity—almost everything that is important.”
31 Mar 2016:
A New, Multi-Colored Way To
Study Cell Regeneration in Zebrafish
Zebrafish have amazing healing capabilities—they can grow back missing limbs and patch an injured heart or spine—but scientists have long been in the dark as to how exactly this process works.
Chen-Hui Chen, Duke University
An engineered zebrafish with multi-colored skin.
Now, a team of scientists at Duke University engineered neurons to create a zebrafish with skin that fluoresces in thousands of colors
in order to visually illustrate how cells regenerate after injury. They found there are three steps to the process: skin cells from neighboring body parts migrate in to cover the new tissue, surviving cells grow in size, and new cells are created. “It is like you have given each cell an individual barcode,” said
Chen-Hui Chen, a postdoctoral fellow at Duke and lead author on the study. “You can precisely see how individual cells collectively behave during regeneration.”
Interview: How Ocean Noise
Wreaks Havoc on Marine Life
Bowing to public pressure, the Obama administration recently reversed an earlier decision to allow oil drilling off the U.S. East Coast. But the five-year moratorium on drilling does not prohibit exploratory seismic air gun surveys
used to locate oil and gas reserves under the seabed, and those surveys are expected to be authorized this spring. Cornell University marine bioacoustics expert Christopher Clark says the testing, which can go on for weeks at a time, will only add to the rising din in the oceans. “Imagine that every 10 seconds there is an explosion that is rattling grandma’s china out of the cupboard,” he says, “and it is falling on the floor.” In an interview with Yale Environment 360
, Clark explains how noise, most of it from ship traffic, severely disrupts marine life, especially among whales. But the good news, he says, is that technologies are being developed to drastically reduce the noise from ships and geological surveying.
Read the interview.
24 Mar 2016:
A Fish With a Pelvis: Another
Clue Into Our Sea-to-Land Evolution
Biologists have long wondered exactly how fish emerged from the sea and transitioned into vertebrates that could walk on land. To date, most of the information on that shift has come from fossils,
A waterfall-climbing fish.
but scientists reported Thursday they have found that a species of fish located only deep in the caves of Thailand walks the same way land vertebrates do
. The blind waterfall-climbing fish, Cryptotora thamicola
, first discovered in 1985, has skeletal features similar to a salamander—including a fully formed pelvis—that enable them to climb up rock walls and feed on microbes and organic matter as water comes crashing down on them, the researchers wrote in Nature Scientific Reports
. “Functionally, it makes perfect sense, but to see it in a fish is incredibly wild,” said
Brooke Flammang, an expert on biomechanics at the New Jersey Institute of Technology and lead author of the study. The discovery could help more fully explain how life evolved from the sea to land.
23 Mar 2016:
Microbes Are Likely Speeding
Up the Melting of the Glaciers
As if soaring global temperatures weren’t bad enough, scientists reported this week that microbes are also speeding up the melting of Arctic ice.
National Parks Service
A pool of meltwater on the Root Glacier in Alaska.
The problem lies in cryoconite, the soil-like composite of dust, industrial soot and photosynthetic bacteria that darkens the surface of ice and causes it to melt, scientists from Aberystwyth University in Wales said. As it melts, ice leaves behind small water-filled holes full of bacteria. The sun-loving microbes then shape the pockmarks’ depth and size to get more light exposure, in turn melting the ice even more—a process previously unaccounted for in global climate change models. "It's only recently that we've begun to understand that these cryoconite holes are dynamic, changing in size and shape,” said
biologist Arwyn Edwards, who led the study. "In the long term, this contributes to the loss of glacier habitats, and the unique microbial biodiversity living on them."
22 Mar 2016:
Old Photos Used to Study
The Fate of a Swedish Seabird Colony
Nearly 100 years of old tourist photos got a second life recently when researchers used them to reconstruct the rise and fall
of a colony of seabirds on the Swedish island of Stora Karlsö. The island, designated a nature preserve in 1880 and a popular tourist destination since the 1920s, hosts a large population of common guillemots, one of the biggest species of auks. Ecologists Jonas Hentati-Sundberg and Olof Olsson of Stockholm University spent five years collecting images of the island from archives, museums, and island visitors in order to count guillemot numbers decade-to-decade. They found that the colony declined in the 1960s and 70s, when contaminants like DDT and PCB were prevalent, but has since rebounded to historically high numbers today, possibly because of an increase in the numbers of forage fish consumed by guillemots. “The population is currently increasing at an unprecedented rate
of about 5 percent annually," said Hentati-Sundberg. "This is interesting in that many common guillemot populations are decreasing worldwide."
21 Mar 2016:
Newly Discovered Butterfly
Could Be Climate Bellwether in the Arctic
Scientists have discovered the first new butterfly species in Alaska in nearly 28 years, according to new research
published in the Journal of Research on the Lepidoptera
The dorsal side of new species Oeneis tanana.
Named the Tanana Arctic, or Oeneis tanana
, the species is thought to be a hybrid and the only butterfly endemic to the state. Because butterflies are so sensitive to environmental change, the Tanana Arctic could serve as an early warning signal to the impacts of climate change in the region, the scientists said. “This butterfly has apparently lived in the Tanana River valley for so long that if it ever moves out, we’ll be able to say ‘Wow, there are some changes happening,’” said
Andrew Warren, the senior collections manager at the McGuire Center for Lepidoptera and Biodiversity at the Florida Museum of Natural History who discovered the species. “This is a region where the permafrost is already melting and the climate is changing.”
16 Mar 2016:
Storks Stop Migrating South
In Favor of Food Waste From Landfills
White storks are no longer migrating to Africa every winter, choosing instead to stay near landfills and other garage heaps in southern Europe that provide scavenged food year round, according to new research published Wednesday in the journal Movement Ecology
University of East Anglia
Storks feeding in a landfill.
Sticking close to uncovered trash piles in Europe means the birds no longer have to expend energy flying all the way south to Africa, and can arrive at the best northern nesting sites and breed earlier in the year. As a result, storks have been having bigger broods and higher fledging survival rates. “Portugal’s stork population has grown 10-fold over the last 20 years,” Aldina Franco, a conservation ecologist at the University of East Anglia in Britain who led the study, said
in a statement. “The country is now home to around 14,000 wintering birds, and numbers continue to grow.” Franco and her colleagues’ findings build on the growing scientific understanding
of how our waste is altering the world’s wildlife.
25 Feb 2016:
Scientists find new large lizard species on remote Papua New Guinea island
Scientists have discovered the first new large lizard species in Papua New Guinea in over 20 years. The lizard was found on Mussau Island, one of the northernmost islands in country, by a team of Finnish and Australian researchers.
The new Varanus semotus.
The scientists have dubbed the new species, Varanus semotus
, a “biogeographical oddity” because it is separated by several hundred miles from its next of kin. Islands in the Pacific Ocean lack predatory mammals, so large lizards, commonly known as monitor lizards, the most famous of which is the Komodo dragon, fill that role. The new lizard measures 3 feet 3 inches, has a black body covered with yellow and orange markings, and a pale yellow tongue. "Isolation is the keyword here," said
Valter Weijola, a graduate student from the University of Turku in Finland who led the trip. "It is what has driven speciation and made the South-Pacific region one of the world's biodiversity hotspots."
24 Feb 2016:
Extended Bleaching Events
Are Killing Corals As Oceans Warm
Rising ocean temperatures are intensifying the die-off of corals around the planet, according to U.S. government scientists. “We are currently experiencing
Bleached coral at the Great Barrier Reef
the longest global coral-bleaching event ever observed,” said Mark Eakin
, head of Coral Reef Watch at the National Oceanic and Atmospheric Administration. Bleaching occurs when corals respond to environmental hazards, such as high ocean temperatures, by expelling the symbiotic algae they need to provide them with sustenance. Eakin predicted that the latest extended bleaching event, which started in 2014, will likely last well into next year, at which time about 60 percent of corals worldwide may be affected. Eakin compares the continuous pressure that reefs have been under in recent years to a boxing bout. “What used to be a one-round fight is turning into a two- and three-round fight,” he says.
18 Feb 2016:
Scientists Map Which Ecosystems
are the Most Vulnerable to Climate Change
Forests, tundras, and alpine areas are some of the world’s most at-risk ecosystems to climate change, according to a new map
published in the journal Nature.
Map of at-risk ecosystems
The study, led by scientists at the University of Bergen in Norway, used satellite data collected from 2000 to 2013 to examine how sensitive plants were to changes in air temperature, water availability, and cloud cover, down to a two-square-mile scale. The scientists used the results to create the Vegetation Sensitivity Index—a visual guide to plants’ climate responses. The Arctic tundra, parts of Europe and Canada’s boreal forest, tropical rainforests in South America, and eastern Australia all registered as some of the most ecologically sensitive regions in the world to climatic changes.
17 Feb 2016:
Reintroduction of Beavers Can Be
Beneficial to the Environment, Study Finds
The reintroduction of beavers to Scotland has proven beneficial to the environment, according to a new study
by researchers at the
Beavers have been reintroduced to Scotland
University of Stirling. Beaver dams increased the retention of organic matter by as much as seven times, and the level of aquatic plant life by 20-fold, researchers said. They also found that the levels of pollutants from agricultural runoff were reduced, with concentrations of phosphorus halved, and nitrate levels lowered by more than 40 percent. “Their dam building skills help restore degraded streams and increase the complexity of the surrounding habitat, increasing the number of species by 28 percent,” lead researcher Nigel Willby said. “The beavers’ engineering is transforming low-quality habitats in regions where the animals have long been absent
Misuse of Mosquito Nets Stressing
Lake Malawi’s Fish Populations
Mosquito nets handed out by international aid organizations to fight malaria are being used by some who live along the banks of Lake Malawi to indiscriminately harvest fish, aggravating the lake’s
Women fishing with mosquito net.
already rapidly diminishing fish stock. Over the last 15 years, UNICEF and the government of Malawi have rolled out nine million free mosquito nets to guard the health of pregnant mothers, their offspring, and refugees against the ravages of malaria. This has been a public health triumph. But the mosquito nets are also being used by villagers for netting fish in Lake Malawi, contributing to the rapid decline of the lake’s fish stocks, which dropped 93 percent between 1990 and 2010, according to the UN’s Food and Agriculture Organization. Overpopulation and deforestation also contribute to the problem, but misuse of mosquito netting is playing a significant role.
04 Feb 2016:
Only Known Wild Jaguar in
the U.S. Filmed in Arizona in Rare Video
of the only known wild jaguar still roaming the United States has been captured using remote sensor
"El Jefe" filmed roaming south of Tucson at night
cameras in Arizona. The big cat, known by the nickname El Jefe
(“The Boss”), is one of only four or five jaguars spotted in the wild in the U.S. in the past two decades. El Jefe
is believed to live in the Santa Rita Mountains, about 25 miles south of Tucson. The footage was captured by Conversation CATalyst
, which has about a dozen cameras in the area where the jaguar lives. Notoriously elusive, the video footage is the product of three years of tracking. Healthy numbers of jaguars, the third largest cats after lions and tigers, once roamed the Southwest, but they all but disappeared about 150 years ago due to habitat loss and hunting, shot to protect livestock. Jaguars are now protected by the Endangered Species Act, although El Jefe
may be the last one in the U.S.
01 Feb 2016:
Lab-raised Caribbean Coral
Grown in the Wild for the First Time
Caribbean coral colonies bred in a lab, using in-vitro fertilization, have for the first time been raised to sexual maturity in their
natural marine habitat, according to findings published in the Bulletin of Marine Science
. Offspring of endangered elkhorn coral were reared from gametes collected in the field and successfully reattached to a reef a year later, where they have grown in size considerably
according to researchers from SECORE International
. Over the past four decades, an estimated 80 percent of all Caribbean corals have disappeared. The elkhorn coral’s decline is so severe that it was the first coral species to be listed as threatened under the U.S. Endangered Species Act in 2006. Due to its large size, branching shape, and preference for shallow waters, the coral is particularly effective at protecting shorelines from incoming storms, as well as providing a critical habitat for many reef organisms. Scientists hope this success will be an important step in helping restore endangered reefs
21 Jan 2016:
Tree Frog Long Believed
Extinct Is Rediscovered, Scientists Say
A specimen of tree frog to be extinct for nearly 150 years, has been found in again in the wild in the jungles of northeast
A new genus of tree frog has been rediscovered.
India, according to an article
published in the journal PLOS ONE
. A group of scientists, led by Indian biologist Sathyabhama Das Biju, identified the frogs as part of a new genus, Frankixalus
, and said the frogs could be living across a wide swath of Asia. But that doesn't mean the frogs are safe, Biju said. They were found at high altitudes in a diversity hotspot under threat from agricultural development. The frog has some very unusual characteristics, such as breeding inside tree hollows 20 feet above ground, where it feeds its tadpoles unfertilized eggs in small pools of water.
11 Jan 2016:
Scientists Warn of Biodiversity
Impacts of Major Hydropower Projects
Hydropower is considered by many to be a key ingredient to reducing carbon emissions and meeting global climate goals,
The Belo Monte dam under construction in the Amazon
but it comes at a great cost to biodiversity, particularly in tropical rainforests, according to a new report
published in the journal Science
. “Far too often in developing tropical countries, major hydropower projects have been approved and their construction begun before any serious assessments of environmental and socioeconomic impacts had been conducted,” says the report's lead author Kirk Winemiller, an aquatic ecologist at Texas A&M University. The dam-building rush, with more than 450 dams planned for the Amazon, Congo, and Mekong river basins alone, impedes tropical fish migration and vastly expands deforestation due to road construction, according to the authors. Other concerns include development of previously inaccessible terrain, as well as methane emissions from newly built reservoirs.
Iberian Lynx Is Back from Brink,
But Still Faces Major Challenges
Efforts to help restore the endangered population of the Iberian lynx are showing signs of success. Chief among them are the captive breeding program, which has
An Iberian lynx in the wild
helped increase the animal’s numbers from a critical low of less than 100 individuals to 160 today. The elegant 25-pound predator, a close relative of the American bobcat, still faces a number of challenges including habitat loss of 95 percent, a high vehicular mortality rate, and a genetic exchange stymied by a lack of wildlife corridors. It remains uncertain, as well, if the lynx can acclimate quickly enough to life at higher, cooler climes, where its main prey, the European rabbit, is already beginning to relocate due to climate change. Read more.
19 Nov 2015:
Genetically Engineered Salmon
Approved for Sale in U.S. Supermarkets
The U.S. Food and Drug Administration today approved
genetically engineered salmon for human consumption, marking the first
AquAdvantage salmon (top) compared to conventional salmon
time an animal with genetic alterations has been cleared for sale in supermarkets across the nation. A long and bitter battle
has surrounded the issue, and this approval comes five years after government reviewers deemed AquAdvantage Atlantic salmon, as the fish is known, safe for consumers and the environment. Opponents have argued that the genetic integrity of wild salmon could be threatened if the GM fish were to escape from contained farms into rivers and oceans. The company says, however, that the fish will be raised on land, thus making escape into the wild impossible, and that the GM salmon can be farmed more efficiently because they have a faster growth rate than conventionally farmed salmon.
13 Nov 2015:
Sharks Will Likely Be Less
Effective Hunters With Climate Change
Sharks will likely become much smaller and less aggressive hunters under the rising CO2 levels and warming oceans associated
Port Jackson sharks are bottom-dwellers.
with climate change, according to a study published in Scientific Reports
by University of Adelaide researchers. In large-tank laboratory experiments with Port Jackson sharks — a bottom-feeding variety that primarily relies on smell to find food — the researchers found that the combination of warmer water and high CO2 increased the sharks' energy requirements and reduced their metabolic efficiency. Elevated CO2 levels also dulled the sharks' sense of smell to the point that they were unable to locate prey — a finding confirmed in previous CO2/olfaction studies. Together, these effects led to dramatic reductions in the sharks' growth rates. "With a reduced ability to hunt, sharks will no longer be able to exert the same top-down control over the marine food webs, which is essential for maintaining healthy ocean ecosystems," said lead researcher Ivan Nagelkerken.
02 Nov 2015:
Urban Fruit Less Polluted and
Often More Nutritious Than Retail Versions
Fruits grown in urban areas, often in abandoned orchards from previous centuries, are proving not only largely free of pollutants,
Measuring nutrients and pollutants in urban fruits.
but more nutritious than their commercial counterparts, according to research from Wellesley College
. Joining forces with the League of Urban Canners, a citizens' group based in Boston, the researchers analyzed nearly 200 samples of apples, peaches, cherries, and other urban fruits and herbs, along with commercial varieties of the same foods. Their findings suggest that eating urban fruit is not a significant source of lead exposure, as compared to the EPA's regulated benchmark for lead in drinking water. The concentrations of the nutrients calcium and iron found were higher in urban fruits for every fruit type tested, while manganese, zinc, magnesium, and potassium concentrations were higher in certain urban fruit types. That is most likely because soils in commercial orchards and fields can become nutrient-depleted, researchers say.
26 Oct 2015:
Major Clue Emerges in Mystery
Of Right Whale Deaths, Researchers Say
Endangered right whales
, especially young calves of the southern population, have been having a hard time
in recent years, and
Southern right whale and calf near Peninsula Valdes
scientists haven't been able to determine why. For example, the average number of right whale deaths per year at Peninsula Valdes, a breeding ground off central Argentina's Atlantic coast, jumped more than 10-fold from 2005 to 2014 — from fewer than six per year to 65 per year, researchers say. Roughly 90 percent of the deaths were calves fewer than three months old. Now researchers have closed in on a suspect: blooms of a type of algae known as Pseudonitschia
, which produce harmful neurotoxins, the researchers write in the journal Marine Mammal Science
. Scientists from the United States and Argentina found that the number of whale deaths at the peninsula closely tracked the concentrations of the toxic algae, offering strong circumstantial evidence that the algal blooms are likely behind the whale deaths.
22 Oct 2015:
The Hard-Working Beaver
Is A Fighter Against Nitrogen Pollution
As beaver populations rebound across North America, the ponds they create are proving to be an important factor in removing rapidly
growing levels of nitrogen
A beaver dam in Alaska.
from waterways and estuaries, according to a new study. By creating ponds that slow down the movement of water, the beavers enable nitrogen — which comes from agricultural runoff, septic systems, and other human sources — to seep into soil, where much of it is broken down by bacteria. Reporting in the Journal of Environmental Quality
, researchers at the University of Rhode Island said that beaver ponds can remove up to 45 percent of nitrogen in the water. One scientist said that when they began to consider the widespread presence of beaver ponds, “we realized that the ponds can make a notable difference in the amount of nitrate that flows from our streams to our estuaries.”