Interview: What’s Damaging U.S.
Salt Marshes and Why It Matters
For centuries, salt marshes along the U.S. coast have been disappearing, with some experts estimating that 70 percent have been lost to development, rising seas,
and other threats. One factor scientists always thought marshes could withstand was nutrient enrichment, such as the flow of nitrogen and phosphorus from fertilizers and septic systems. But a nine-year study led by Marine Biological Laboratory scientist Linda Deegan shows that an over abundance of nutrients may be contributing to the demise of these salt marshes. In a Yale Environment 360
interview, Deegan describes the study's implications and the vital services that would be lost if marshes disappear, from nourishing marine species to providing a barrier for coastal communities during storms such as Hurricane Sandy. Read the interview
21 Dec 2012:
Changing Oceans May Be Adding
To U.S. Fisheries Decline, Scientists Say
As U.S. fishing regulators weigh stricter catch quotas to allow time for critical species to recover in the waters of New England, scientists say that changing ocean conditions may be a factor in historic fish declines, not just decades of overfishing. Warmer ocean temperatures and changing ecosystems are contributing to declining populations of cod and flounder
in the northeastern U.S., government officials say. In the Gulf of Maine this year, water temperatures were the highest ever recorded, according to the Northeastern Regional Association of Coastal and Ocean Observing Systems. National Oceanic and Atmospheric Administration (NOAA) scientists say that about half of 36 fish stocks — including cod and flounder — have been shifting northward into deeper, cooler waters for four decades. And while some regulators say the only chance of restoring populations is for tougher quotas on bottom-dwelling “groundfish” species, the New England Fishery Management Council this week delayed a vote on such cuts
after fishermen said the reductions would devastate their industry.
06 Dec 2012:
Google Images Document
Devastation of 2011 Tsunami in Japan
As part of an ongoing project to digitally archive the aftermath of the 2011 tsunami in northeastern Japan, Google has published several new panoramic images
that provide a sobering glimpse of the widespread
devastation in communities across the region. The images, taken with the company’s Street View technology in four cities in the Tōhoku region, allows users to take a virtual tour of seriously damaged buildings before they are demolished. One panoramic view of a public housing project illustrates the height of the tsunami wave, which ruined everything up to the fourth floor of the building. Another image, of the condemned Ukedo Elementary School, shows the collapsed auditorium floor beneath the banner of a graduation ceremony that was never held. The images were added to Google’s “Memories for the Future
” website, which is chronicling the affected areas from before and after the tsunami.
30 Nov 2012:
Accelerated Ice Sheet Melt
At Both Poles Documented in Study
The ice sheets of Greenland and Antarctica are losing three to five times as much ice annually
as they did two decades ago, a rate of ice loss equivalent to sea level rise of 0.04 inches per year, according to a new study supported by NASA and the European Space Agency
. In an analysis of data from 10 different satellite missions, the international team of 47 experts calculated that the rate of melt in Greenland is five times greater than during the mid-1990s. While the new findings on total ice loss fall within the range produced by the Intergovernmental Panel on Climate Change in 2007, the new study provides a more definitive assessment that Antarctica’s ice sheets, like Greenland’s, are shrinking. Combined, these ice sheets have added .44 inches (11.1 millimeters) to sea levels worldwide since 1992, accounting for about 20 percent of total sea-level rise during that period. “This will give the wider climate science community greater confidence in ice losses and lead to improved predictions of future sea-level rise,” said Andrew Shepherd, a scientist at the University of Leeds and co-leader of the study, which is published in the journal Science
26 Nov 2012:
Snails in Southern Ocean
Showing Effects of Ocean Acidification
The shells of some sea snails in the Southern Ocean are already dissolving as a result of ocean acidification
, according to a new study. In an analysis of free-swimming pteperods collected from Antarctic waters in 2008, scientists found that the outer layers of the animals’ shells showed signs of unusual corrosion, potential evidence that ocean acidification caused by excess carbon dioxide in the atmosphere may already be disturbing vulnerable marine species. Laboratory tests have shown that acidic water threatens many invertebrate marine species, such as clams and corals, since it hinders their ability to grow shells and exoskeletons. The most vulnerable species are those, like pteropods, that build their shells from aragonite, a form of calcium carbonate that is sensitive to increased acidity, according to the study, published in Nature Geoscience
16 Nov 2012:
Majority of Marine Species
Still Remain Unknown to Scientists
While more new marine species were identified over the last 10 years than during any previous decade, as many as two-thirds of the plant and animal species living in the oceans may still be unknown to scientists, a new study says. Writing in the journal Current Biology
, a team of international scientists estimates that there are
The marbled swimming crab
likely 700,000 to 1 million species in the oceans, of which only 226,000 species have so far been identified
. Another 65,000 are sitting in scientific collections awaiting identification, according to the study. The study, which was produced by 270 experts from 32 countries, represents the most comprehensive inventory of marine life, and notes that the majority of unknown species are composed of crustaceans, mollusks, worms, and sponges. “For the first time, we can provide a very detailed overview of species richness, partitioned among all the marine groups,” said Ward Appeltans, a biologist at UNESCO's International Oceanographic Commission and one of the study’s authors. The complete inventory can be viewed online at www.marinespecies.org
13 Nov 2012:
Gains in Antarctic Sea Ice Cover
Triggered by Wind Shifts, Study Says
Scientists say they have the first direct evidence that changes in Antarctic sea ice drift caused by changing winds have produced an increase in Antarctic sea ice
cover over the last two decades even as historic declines have been observed in the Arctic. Using more than 5 million measurements of daily sea ice movement collected over 19 years, researchers from NASA and the British Antarctic Survey detected long-term changes in sea ice drift
, a phenomenon that has caused overall increases in sea ice cover. While sea ice around Antarctica is constantly being blown away from the continent by northerly winds, the rate of ice movement in some areas has doubled since 1992, causing total sea ice, which reflects heat from the sun, to expand out from Antarctica, according to their findings, which were published in Nature Geoscience
. “The Antarctic sea ice cover interacts with the global climate system very differently than that of the Arctic, and these results highlight the sensitivity of the Antarctic ice coverage to changes in the strength of the winds around the continent,” said Ron Kwok of NASA’s Jet Propulsion Laboratory.
06 Nov 2012:
World’s Rarest Whale Species
Identified After New Zealand Beaching
Scientists have confirmed that two whales that washed onto the New Zealand coast two years ago were spade-toothed beaked whales, an enigmatic species so rare that no human is known to have ever seen one alive
. Writing in the journal Current Biology
, New Zealand and U.S. researchers provide the first full description of the species, which previously was known only from three skull fragments recovered over a 140-year span, the most recent of which was found 26 years ago. When conservation workers initially found the adult whale and her 11-foot male calf on a New Zealand beach in December 2010, they thought they were Gray’s beaked whales, a far more common species. But DNA tests of tissue samples collected from the animals revealed that they were actually spade-toothed beaked whales
), a species whose males have blade-like tusk teeth, and researchers later exhumed the whales to conduct additional tests.
05 Nov 2012:
China and Russia Block
Proposal to Protect Antarctic Waters
International talks to protect large areas of the Southern Ocean surrounding Antarctica collapsed last week
after several nations, including China, blocked the proposal over concerns about fishing access, according to reports. Representatives from 25 member states — including China, Russia, the U.S., the European Union — gathered in Australia to negotiate plans that would have protected approximately 4 million square kilometers in the Southern Ocean, including provisions that would have banned industrial fishing operations. Some regions would have also been set aside for scientific research into the effects of climate change on polar ecosystems. According to The Australian newspaper
, China and Russia were among the nations that rejected the plans. Alex Rogers, a conservation biologist at the University of Oxford, told Nature
that the stalled talks reflect a wider “global dichotomy” about how to manage marine resources, with some states looking to impose greater conservation and management policies and others targeting increased exploitation. “Time really is running out on these issues,” he said. “If we don’t get protection in place now, exploitation of these systems will increase.”
02 Nov 2012:
Sea-Level Rise Projections
Ignored Critical Feedbacks, Researcher Says
A U.S. researcher says projected sea-level rise over the next century has been underestimated because current models fail to consider several critical feedbacks
that might accelerate rising seas in the coming decades. While the 2007 report of the Intergovernmental Panel on Climate Change predicted that global sea levels could rise 0.2 to 0.5 meters by 2100, current projections suggest that seas could rise a meter or more. One of the factors ignored by earlier models, says University of Colorado geologist Bill Hay, is the influx of warm, briny ocean water into the Arctic that occurs when melting fresh water is released, a phenomenon he says acts as a sort of “heat pump” in the Arctic, adding more ice-free waters, which then absorb more solar energy. According to Hay, who will present his findings at the annual meeting of The Geological Society of America, another factor that was ignored is the potential melting of large ice sheets in Greenland and western Antarctica. A third feedback, he said, is the vast amounts of groundwater being removed to address humankind’s surging water needs, much of which ultimately ends up in the oceans.
01 Nov 2012:
Timelapse of Hurricane Sandy
Shows Birth and Death of Historic Storm
As the storm that was Hurricane Sandy weakened over Pennsylvania, NASA released a timelapse animation of the lifespan of the massive storm
, tracking its path from
the Caribbean, where it developed, to its violent landfall on the mid-Atlantic coast of the U.S. The collection of images, taken by the NASA GOES-13 satellite from Oct. 23 to Oct. 31, illustrates the storm gaining intensity as it traveled north, at times reaching nearly 1,000 miles in width. When the storm reached the mid-Atlantic on Oct. 29, it became wedged between a cold front over the Appalachian Mountains and a high-pressure air mass over maritime Canada, preventing it from moving north or east and instead driving it ashore. At that point Sandy became a Nor’easter, triggering historic storm surges in coastal areas of New York and New Jersey and blizzard conditions in the mountain regions. Meteorologists say the swath of high winds produced by Sandy while it was a hurricane covered nearly 2 million square miles
In New York, The Rising Threat Of
Flooding Was Predicted for Years
While climate experts hesitate to say Hurricane Sandy was caused by climate change, scientists for years have predicted that such devastating events would become increasingly common as sea levels rise and ocean
Rising Currents: A 2010 exhibit showed visions of New York adapting to climate change.
temperatures become warmer. For more than a decade, reports have warned that climate change will likely trigger more intense hurricanes and more frequent and severe flooding in low-lying areas
, such as occurred in New York and New Jersey. And with sea levels projected to rise by as much as six inches per decade by mid-century and as much as several feet by 2100,
experts say New York City’s flood zone will continue to expand
. In Sandy's wake, New York officials are starting to discuss projects that might withstand such surges
, including building a levee system or barriers.
25 Oct 2012:
Rapid Thinning of Glaciers
Seen After Collapse of Antarctic Ice Shelf
NASA has released satellite photos that vividly depict the precipitous thinning and retreat of two Antarctic glaciers
following the disintegration of the Larsen B Ice Shelf. That ice shelf — which floated on top of the
Weddell Sea and once was the size of Connecticut — collapsed in 2002 after several years of warm summer temperatures. The Larsen B had acted as a buttress slowing the flow of numerous glaciers into the sea. The NASA satellite images, taken in 2002 and in 2012, demonsrate how swiftly the Green and Hektoria glaciers behind the ice shelf surged into the ocean. The 2002 photo shows the glaciers covering much of nearby mountain ridges and the termini, or end points, of the glaciers are not visible. The 2012 photo shows that the thinning glaciers now cover considerably less of surrounding mountain ridges and the termini of both glaciers are visible. The 2012 image also shows the numerous crevasses that have formed as the glaciers have thinned.
24 Oct 2012:
Plastic Waste Increasing
On Remote Arctic Seabed, Cameras Reveal
Deep-sea cameras deployed to monitor biodiversity on the Arctic seabed have documented a significant rise in the amount of plastic waste and other litter
on the remote sea floors of the Far North, according to a new study. While looking at many thousands of seabed photos taken in 2011 between Greenland and the Norwegian island of Spitzbergen, deep-sea expert Melanie Bergmann of the Alfred Wegener Institute for Polar and Marine Research was struck by the number showing plastic waste. In a detailed analysis of the photographs — which are taken every 30 seconds by a deep-sea observatory reaching depths of 2,500 meters — Bergmann and her colleagues found that while plastic waste was seen in only one percent of photographs taken in 2002, that number had jumped to 2 percent in 2011. Two percent may not seem like a high occurrence, Bergmann said, but the quantities observed in this remote Arctic region were greater than recorded in a deep-sea canyon near Lisbon, Portugal. According to the study, published in the journal Marine Pollution Bulletin
, about 70 percent of the plastic litter had come in contact with deep-sea organisms.
22 Oct 2012:
Shifting Arctic Wind Patterns
May Cause Increased Melt, Study Says
U.S. scientists say unusual air pressure patterns over the Arctic during the month of June in recent years have altered wind patterns in the region, funneling warmer air into the Arctic and contributing to record low Arctic
Air pressure over the Arctic, 2007-2012.
summer sea ice extent from 2007 to 2012. Writing in the journal Geophysical Research Letters
, a team of researchers illustrated how the formation of two unusual high pressure areas over the North American Arctic and Greenland disrupted the normal westerly flow of winds, creating “blocking highs” that led to an unusually strong flow of warm southerly air. That sent more warm air into the central Arctic and Greenland
, which may have been a factor in unusually dramatic summer thaws beginning in 2007. While it is unclear why these unusual patterns of high pressure have occurred in each of the last six Junes, NOAA researcher James Overland believes it may be related to declining snow cover in the Canadian Arctic in recent years. “We don’t know that part of the story yet,” he said.
Solar Geoengineering Projects
Could Be More Effective on Regional Scale
A new modeling study by several geoengineering experts suggests that injecting aerosols into the atmosphere to block more of the sun’s energy and reduce temperatures could be most effective when done on a region-by-region basis
. The study, published in the journal Nature Climate Change
, said that injecting aerosols over the Arctic Ocean in summer, for example, might be an effective way to not only slow the rapid loss of Arctic sea ice but possibly even restore it to pre-industrial levels. The researchers — led by David Keith of Harvard University, Ken Caldeira of the Carnegie Institution for Science, and Douglas McMartin of the California Institute of Technology — cautioned that their models were rough and that bringing about changes in regional climate patterns can have global effects
. But they said the study shows the need for more detailed research into how solar geoengineering techniques could be used to slow or reverse the effects of climate change on rapidly warming areas. “Our research goes a step beyond the one-size-fits-all approach to explore how careful tailoring of solar geoengineering can reduce possible inequalities and risks,” said Keith.
19 Oct 2012:
Increased Ocean Acidification
May Alter The Acoustics of Seawater
Increased ocean acidification over the next century could alter the acoustic properties of seawater
, giving the planet’s oceans the same hi-fi sound they had during the age of the dinosaurs. In an analysis of ocean acidity over 300 million years, U.S. researchers David G. Browning and Peter M. Scheifele calculated that increased ocean acidity as a result of global warming will have a negative effect on the absorption of low-frequency sounds. By 2100, they predict, sounds near the oceans surface, such as whale songs or sounds created by ships, will travel perhaps twice as far as they do today. The scientists based their calculations on historic levels of boron in seafloor sediments and an analysis of its sound-absorption traits and impacts on low-frequency transmission. “[This knowledge] impacts the design and performance prediction of sonar systems,” said Browning, who will present the findings at the annual meeting of the Acoustical Society of America
. “It affects estimation of low frequency ambient noise levels in the ocean. And it's something we have to consider to improve our understanding of the sound environment of marine mammals and the effects of human activity on that environment."
18 Oct 2012:
Increased Nutrient Levels
May Drive Collapse of Salt Marsh, Study Says
Increasing levels of nutrients seeping from septic systems and lawn fertilizers may be driving the steady decline of salt marshes
that has occurred along the U.S. East coast in recent decades, a new study has found.
David S. Johnson/MBL
While scientists had long believed that salt marshes have an unlimited capacity for removing nutrients such as nitrogen and phosphorus, a long-term experiment by researchers at the Marine Biological Laboratory (MBL) at Woods Hole, Mass. found that nutrient enrichment can drive salt-marsh loss. Over nine years, the researchers added amounts of nitrogen and phosphorus to tidal waters flushing through salt marsh in an undeveloped coastal area consistent with the nutrient levels present in developed areas such as Cape Cod, Mass. and Long Island, N.Y. Within a few years, they observed wide cracks in the grassy banks of tidal creeks; eventually, the researchers say, the banks would collapse altogether into the creek. “The long-term effect is conversion of a vegetated marsh into a mudflat, which is a much less productive ecosystem,” said Linda Deegan, an MBL scientist and an author of the study published in Nature
16 Oct 2012:
Online Atlas Illustrates
Critical Areas for World’s Seabirds
A new online atlas provides the first global inventory of ocean sites critical to the world’s seabirds, a free digital resource that its creators hope will help guide protective policies and the creation of conservation areas globally. The site (www.birdlife.org/datazone/marine
was created by the group BirdLife International, identifies 3,000 important sites that are critical to seabirds, from penguins to sandpipers, including breeding grounds, foraging areas, and migration routes. These so-called “important bird areas” (IBAs) comprise about 6.2 percent of the world’s oceans, according to BirdLife International. While seabirds are particularly vulnerable to threats
because of the great distances they travel across international waters, many conservation groups have cited a lack of data as a reason for inaction in protecting these areas, Ben Lascelles of BirdLife International told Reuters
15 Oct 2012:
‘Rogue’ Geoengineering Scheme
In Pacific Violated UN Rules, Groups Say
A project sponsored by a controversial U.S. businessman dumped about 100 tons of iron sulphate into the Pacific Ocean this summer, an experiment in geoengineering that environmental groups say violated international agreements, The Guardian has reported
. According to the report, satellite images appear to confirm that the iron dumped from a fishing boat sponsored by Russ George, the former CEO of Plankton Inc., triggered a nearly 10,000-squre-kilometer plankton bloom off Canada’s west coast. Some researchers believe this technique could emerge as a critical strategy in reducing the effects of climate change since such blooms are capable of sucking carbon out of the atmosphere and ultimately trapping it deep in the ocean. The experiment took place west of the islands of Haida Gwaii, where George convinced the council of an indigenous village to approve the project. Critics say it should not have taken place without proper scientific assessment and violated existing UN resolutions. Scientists say it is unclear whether such iron fertilization damages ocean ecosystems, triggers toxic tides, or worsens the effects of ocean acidification.
04 Oct 2012:
New Cleanup Method Offers
Major Solution to Oil Spills, Study Claims
Scientists have developed a superabsorbent material they say offers a cost-effective way to remove, recover and clean up large oil spills
. Writing in the journal Energy & Fuels
, Pennsylvania State University
researchers Xuepei Yuan and T. C. Mike Chung describe a polymer material that they say can absorb 40 times its own weight in oil, transforming spilled material into a solid, oil-containing gel that is strong enough to be collected and transported to oil refineries for reprocessing. While many of the methods typically used to clean up oil spills — including booms, skimmers, burning, and the use of dispersants — waste most of the spilled oil and leave behind significant levels of environmental pollution, the scientists say their so-called polyolefin oil-SAP technology offers a potentially “complete solution” to dealing with oil spills. They say the material does not absorb water, is buoyant, and is relatively inexpensive.
02 Oct 2012:
Great Barrier Reef Lost
Half of Coral Cover Since 1985, Study Says
The Great Barrier Reef has lost half of its coral cover in just 27 years, with most of that decline coming as a result of heavy storms, predation by crown-of-thorn starfish, and coral bleaching caused by warming ocean temperatures. In a comprehensive survey of 214 reefs, researchers at the Australian Institute of Marine Science (AIMS) found that coral cover declined from 28 percent in 1985 to 13.8 percent this year
. Intense tropical storms, particularly in the central and southern parts of the reef, have caused about 48 percent of the coral loss, researchers say. An explosion in populations of starfish along the reef caused about 42 percent of the decline; about 10 percent was caused by major bleaching events. Reefs are typically able to regain their coral cover after such disturbances, said Hugh Sweatman, a lead author of the study, published in the Proceedings of the National Academy of Sciences
. But recovery takes 10-20 years, he noted. The study found efforts to reduce starfish populations could help increase coral cover at a rate of 0.89 percent per year.
28 Sep 2012:
Decline in Fisheries
Can Still be Reversed, Study Says
Although the majority of global fisheries remain in decline, they can still rebound if managed sustainably
, according to a new study. In a comprehensive statistical analysis of the world’s 10,000 fish stocks, nearly 80 percent of which are not regulated, a team of U.S. scientists found that the world’s smaller, managed fisheries are in far worse shape than larger, regulated ones. But while those smaller fisheries, such as those for snapper, are in steep decline, “they’re not yet collapsed,” said Christopher Costello, an economist at the University of California at Santa Barbara and lead author of the study, published in the journal Science
. According to the analysis, effective management of unregulated fisheries could boost global fish abundance by 56 percent. “If we turn things around now, we can recover them in a matter of years, not decades, and that has big implications for conservation and food security,” Costello said. According to the study, major gains have been made in large fisheries, such as skipjack and albacore tuna, where strong science-based management policies have been enacted
, including the closing of some areas to let stocks recover.
27 Sep 2012:
Unusual Series of Quakes
Indicate Tectonic Breakup in Indian Ocean
Two massive earthquakes in April in the Indian Ocean and an unusual series of aftershocks may signal the formation of a new tectonic plate boundary within Earth’s surface
. Reporting in the journal Nature
Click to enlarge
Keith Koper/University of Utah
Fault activity in the Indian Ocean.
scientists say that an analysis of the two April 11 earthquakes — one of magnitude 8.6 and the other of magnitude 8.2 — shows that they were not typical quakes that occur when one plate slides under another or two plates slip horizontally along a fault line. Instead, the earthquakes, caused by breaks along four faults in the Indian Ocean and accompanied by an unusually large number of aftershocks, indicate that the Indo-Australian tectonic plate may be breaking up. “It’s the clearest example of newly formed plate boundaries,” said Matthias Delescluse, a geophysicist at the Ecole Normale Superieure in Paris. The researchers said that the massive and deadly 2004 Indian Ocean earthquake and tsunami, as well as another earthquake in 2005, may also have been related to the April quakes and the breakup of the Indo-Australian plate.
25 Sep 2012:
Coral Biodiversity Hotspot
Is Found in Western Indian Ocean
The western Indian Ocean, especially the waters between Madagascar and Africa, contain one of the highest levels of coral diversity worldwide
, with 369 coral species identified in a recent study and more still to be identified. Scientists say the western Indian Ocean may contain as much coral biodiversity as Australia’s Great Barrier Reef, though not as much as the world’s richest region for corals, the so-called coral triangle in Southeast Asia. Reporting in the journal PLoS ONE
, David Obura, a scientist with the Group Coastal Oceans Research and Development in the Indian Ocean, said that 10 percent of the species are found only in the western Indian Ocean. He said the northern end of the Mozambique Channel, between Madagascar and mainland Africa, contains roughly 250 to 300 coral species. Meanwhile, Australian scientists report that water temperatures around the Great Barrier Reef have increased steadily in the last 25 years
, in some places rising as much as .5 degrees C. Such increases can contribute to coral bleaching, which can lead to mass coral die-offs.
21 Sep 2012:
U.S. Fishing Catch Reached
17-Year High in 2011, NOAA Says
U.S. commercial fishermen landed more than 10.1 billion pounds of fish and shellfish in 2011, a 17-year high attributed in part to policies aimed at rebuilding fisheries nationwide, according to a report from the National Oceanic and Atmospheric Administration (NOAA)
. The annual catch was 22.6 percent greater than 2010 and, with a value of $5.3 billion, a 17-percent increase in value compared with a year earlier. Officials say catch increases are evidence that fish populations are increasing due to better fisheries management. While all nine of NOAA’s fishing regions saw an increase in catch volume and value, much of the overall increase was a result of increased catches of Gulf of Mexico menhaden, Alaskan pollock, and Pacific hake. NOAA said key fisheries remain at risk
, with disasters declared for the cod fishery in New England, oyster and blue crab fisheries in Mississippi, and Chinook salmon in Alaska’s Yukon and Kukokwin rivers.
20 Sep 2012:
Arctic Sea Ice Extent
Reaches a Dramatic New Low
As the summer melt season ends, Arctic sea ice extent has now fallen to an exceptionally low level
, covering an area only half the size of the 1979 to 2000 average. The
Colorado-based National Snow and Ice Data Center (NSIDC) reported that as of September 16, Arctic sea ice extent was only 1.32 million square miles, which is 18 percent below the previous record low of 1.61 million square miles, set in September 2007. “We are now in uncharted territory,” said NSIDC director Mark Serreze. “While we’ve long known that as the planet warms up, changes would be seen first and be most pronounced in the Arctic, few of us were prepared for how rapidly the changes would actually occur.” A key reason for the precipitous decline of sea ice extent is that Arctic Ocean ice has become so thin after years of rapidly rising temperatures in the region, with thick, multi-year ice being replaced by thin, year-old ice that swiftly melts in summer.
17 Sep 2012:
Most Coral Reefs At Risk
Even if Warming Limited to 2 Degrees C
Most of the world’s coral reefs will likely be subject to long-term degradation even if global warming is limited to 2 degrees Celsius
, and as much as one-third of coral reef systems will likely be vulnerable to threats even under the most optimistic climate projections, a new study says. In an analysis of the potential effects of heat stress on coral reef systems under different climate change scenarios, a team of researchers found that most potential outcomes will likely trigger more frequent and intense mass-bleaching events. If global mean temperature increases exceed 2 degrees C, coral reefs “might no longer be prominent coastal ecosystems,” said Katja Frieler, a researcher at the Potsdam Institute for Climate Impact Research and lead author of the study, published in Nature Climate Change
. Under the most optimistic scenarios — including aggressive climate mitigation and assumptions that coral systems can adapt to warming conditions — one third of the world’s coral systems would still be subject to severe degradation, the study said.
11 Sep 2012:
Small Forage Fish Species
Worth 20 Percent of Global Fisheries
The world’s forage fish species — small, schooling fish such as herring and sardines that play a key role in the food web in marine ecosystems — represent about 20 percent of the global values of all marine fisheries
, according to a new study. In a comprehensive analysis of dozens of food web models from around the planet, scientists from the State University of New York at Stony Brook calculated that these small fish contribute $16.9 billion to global fisheries each year, either as direct catch or as food for larger fish. According to their findings, the direct catch value for forage fish worldwide is $5.6 billion — with the largest market being the Peruvian anchoveta fishery — while the value of fisheries depending on these small fish is about $11.3 billion. “In addition to their value to commercial fishing and other industries that depend on them for their products, forage fish play valuable roles in global ecosystems while they are still in the water,” said Ellen K. Pikitch, co-lead author of the study, published in the journal Fish and Fisheries
31 Aug 2012:
Method Uses DNA Technology
To Track Marine Life From Water Samples
Danish scientists say they have developed a process to detect the presence of fish and whales in local waters through the DNA analysis of water samples
, an innovation that will help researchers more safely monitor biodiversity in the world’s oceans. Using sophisticated DNA sequencing technology, researchers from the University of Copenhagen say they were able to detect DNA from 15 different fish species from a half-liter sample of seawater. According to Philip Francis Thomsen, one of the authors of the study published in the journal PLoS ONE
, tests of the water revealed the presence of small and large fish — including common species and species rarely or never recorded by conventional monitoring — in the waters off Denmark. “Cod, herring, eel, plaice, pilchard and many more have all left a DNA trace in the seawater,” he said. The researchers say the use of DNA technology may offer a less invasive way of monitoring marine populations than traditional methods, such as the use of trawls and pots. In addition, such DNA tests could be conducted almost anywhere and on any species, unlike typical monitoring methods that focus mostly on commercial fish species.