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.
28 Aug 2012:
Arctic Ice Reaches Record Low
The extent of ice covering the Arctic Ocean has reached a new record low
and will likely continue to retreat until mid-September, when re-freezing begins to occur, according to satellite observations. NASA and the
U.S.-funded National Snow and Ice Data Center (NSIDC) reported that sea ice extent fell in the past few days to 1.58 million square miles (4.1 million square kilometers), breaking by 27,000 square miles the previous record low extent, set in September 2007. Summer sea ice extent has declined by more than 40 percent since satellites began tracking it in 1979, and sea ice now covers less than 30 percent of the Arctic Ocean.
Sea ice experts say that both the extent and thickness of Arctic summer sea ice has declined so precipitously in the face of rapidly rising temperatures that the Arctic basin appears to be heading for largely ice-free summers within a decade or two. “Parts of the Arctic have become like a giant slushy,” said Walt Meier, a research scientist at the NSIDC. The disappearing sea ice is creating ever-larger areas of dark, heat-absorbing waters, which is further increasing temperatures in the Arctic and hastening the melting of Greenland’s massive ice sheets.
24 Aug 2012:
Drought Conditions Trigger
Smallest Gulf ‘Dead Zone’ in Years
U.S. scientists say the nation’s worst drought in five decades has had at least one positive effect: the smallest so-called “dead zone” seen in the Gulf of Mexico in years
. In a 1,200-mile research cruise conducted in the
Algal blooms in the Gulf of Mexico
waters of the gulf this month, scientists from Texas A&M University found only 1,580 square miles of oxygen-depleted, or hypoxic, water in the gulf, compared with 3,400 square miles last August. The hypoxic zone is created when algal blooms, caused by large amounts of fertilizer and nutrients washing into the gulf, remove oxygen from the water and suffocate marine life. According to the researchers, hypoxia was found only in the waters near the Mississippi River delta, which accounts for nearly 90 percent of all freshwater runoff in the gulf; no hypoxia was observed off the Texas coast. “What has happened is that the drought has caused very little fresh-water runoff and nutrient load into the gulf, and that means a smaller region for marine life to be impacted,” said Steve DiMarco, an oceanographer at Texas A&M.
16 Aug 2012:
Ocean Health Index Evaluates
State of Waters Around the Globe
An international team of researchers has released a new tool that evaluates the state of the world’s oceans
, a so-called Ocean Health Index that its creators say provides the first comprehensive assessment of the relationship
between the planet’s marine regions and human communities. While previous assessments of ocean health were based on the level of “pristineness,” this index is framed in terms of the benefits humans derive from the oceans and the extent to which communities maintain a sustainable marine environment. Using a wide range of criteria — including water quality, marine biodiversity, and the condition of coastal areas — the researchers ranked ocean areas worldwide on a scale from 0 to 100. According to their analysis, published in the journal Nature
, the global ocean received an overall score of 60, while scores for individual areas ranged from 36 to 86. The waters around Jarvis Island, near Hawaii, ranked highest
; the waters off the West African nation of Sierra Leone ranked lowest.
01 Aug 2012:
New Whale Recordings Hint
at Bowhead Recovery off Greenland
A wide array of whale songs recorded in the icy waters off Greenland indicates that populations of the endangered bowhead whale, nearly hunted to extinction in the last two centuries, may be experiencing a rebound
A bowhead whale
collecting 2,144 hours of audio recordings in the waters between Greenland and Norway from September 2008 to July 2009, an international team of scientists detected a surprising variety and duration of whale songs. Not only did the recordings yield roughly five months of near-continuous singing, but they revealed more than 60 unique “songs,” most likely belonging to individual whales, according a study published in the journal Endangered Species Research
. Since scientists believe male bowheads sing during mating season — and because most whale species are believed to sing the same song throughout their lives — the findings could suggest that bowhead populations in that area exceed 100 whales, far more than previously believed; only 40 bowhead sightings have been reported in that area since the 1970s, according to the researchers.
Listen to the bowheads’ song
31 Jul 2012:
Low Levels of Caffeine Found
In Waters of U.S. Pacific Northwest
In a new study, scientists document low levels of caffeine pollution in the waters off the Oregon coast, fresh evidence that contaminants from human waste are entering marine ecosystems with unknown risks to wildlife and human health. In a series of tests conducted at 14 coastal locations, researchers found that caffeine levels were higher — about 45 nanograms per liter — in remote waters, while levels were below reporting limits (about 9 nanograms per liter) near “potentially polluted” areas such as sewage treatment plants, the mouths of rivers, and larger communities, National Geographic reports
. According to the findings, published in the journal Marine Pollution Bulletin
, the higher levels are likely occurring near sites with on-site waste disposal systems that are subject to less monitoring than larger wastewater treatment plants. While the environmental effects of such low-level contamination are not known, experts say they are a reminder of the range of pollutants — from pharmaceuticals to artificial sweeteners — entering natural ecosystems through human waste.
Unusual Number of Grizzly and
Hybrid Bears Spotted in High Arctic
Two Canadian biologists have reported sighting a handful of grizzly bears and hybrid grizzly/polar bears at unusually high latitudes in the Arctic, indicating that the interbreeding of the two bear species is becoming more common as the climate warms and grizzlies venture
Photo courtesy of Jodie Pongracz
A hybrid polar/grizzly bear in the Canadian Arctic
farther north. The sightings of three grizzly bears and two hybrid bears, made in late April and May by biologists from the University of Alberta, represent an unprecedented cluster of these animals at such high latitudes. The biologists even took DNA samples from a grizzly bear at 74 degrees North latitude. Scientists suggested that some grizzly bears may be leaving the Canadian Arctic mainland and traveling roughly 400 miles over sea ice as they pursue a caribou herd that annually migrates over ice from the mainland to Victoria Island in the High Arctic. Unable to get back because of rapidly melting ice, some of these grizzly bears have evidently managed to adapt to life in the polar bear’s world, eating seals as they overwinter and mating with polar bears.
25 Jul 2012:
Entire Greenland Ice Sheet
Experiences Significant Surface Melting
New NASA satellite images show that the surface of virtually the entire ice sheet covering Greenland experienced melting in mid-July
, a phenomenon not
seen in three decades of satellite observations. Temperatures rose so high that ice on the Greenland’s highest peak, Summit Station, turned to slush, NASA said. Until the severe melting earlier this month, the greatest extent of surface melting observed by satellites over the past three decades covered about 55 percent of the ice sheet; on July 12, 97 percent of the ice sheet experienced surface melting. Ice cores from Greenland show that such melting events have occurred roughly every 150 years, but Greenland’s ice sheet has been experiencing rapid melting in the past decade and if another major melting event occurred within the next 10 years it could disrupt the stability of the ice sheet
, said Thomas Mote, a climatologist at the University of Georgia. “When we see melt in places that we haven’t seen before, at least in a long period of time, it makes you sit up and ask what’s happening,” NASA scientist Waleed Abdalati told the BBC
Maya Lin: A Memorial to
A Vanishing Natural World
The woman who designed the Vietnam Veterans Memorial is now focused on the mass extinction of species, a threat she is highlighting on a dynamic interactive Web site. In an interview with Yale Environment 360
, Maya Lin talks about the origins of her What is Missing? project, the media techniques she and her collaborators are using to draw attention to the biodiversity crisis, and the actions that give her hope that we can reverse the tide of nature’s destruction. “I am going to try to wake you up to things that are missing that you are not even aware are disappearing,” Lin said.
Read more and listen to an audio podcast
19 Jul 2012:
Shows Ability to Trap CO2 in Ocean
An eight-year German research effort has shown that under the right conditions seeding the ocean with iron can trigger phytoplankton blooms that suck carbon out of the air and trap it deep in the ocean,
a potentially important breakthrough in the nascent field of climate geoengineering. Reporting in the journal Nature
, scientists from the Alfred Wegener Institute for Polar and Marine Research said that adding 14 tons of iron sulfate to the Southern Ocean near Antarctica resulted in a significant phytoplankton bloom extending more than 300 feet deep. That bloom consisted of large masses of algae, mainly composed of diatoms, which absorbed carbon dioxide from the atmosphere. More than 50 percent of the carbon-rich algae then sunk to a depth of more than 3,000 feet, where it is likely to be trapped for centuries. The German research team conducted the iron-seeding experiment in 2004 and then spent eight years analyzing the data. Previous iron-seeding experiments have had difficulty tracking the path of CO2 pulled out of the atmosphere because of swirling currents and other complications. But the Wegener team said its experiment had succeeded because scientists found a 40-mile-wide column of water that was isolated from other ocean currents.
16 Jul 2012:
Warmer Ocean Waters
Lead To a Glut of Lobsters in Maine
Warmer Atlantic Ocean temperatures off the coast of Maine have caused the state’s bountiful supply of lobsters to shed their shells and come onto the market six weeks earlier than normal, creating a glut that has driven prices sharply down.
The state’s 5,000 lobster fishermen are receiving less than $3-per-pound at the dock for their catch, which is below the $4-per-pound break-even point. As a result, many lobsterman have stopped fishing and are waiting for the oversupply of lobster to ease before heading back out on the water. An extremely mild winter and spring in New England has increased ocean temperatures, which in turn has caused Maine’s lobsters to shed their shells far earlier than normal. The abundance of so-called soft-shelled lobsters led to the largest lobster harvest on record in June, state officials said. The warmer temperatures also caused a boom in lobsters in Canada, which has exacerbated the glut. Soft-shelled lobsters are more difficult to ship out of state than hard-shelled ones, meaning Maine’s processing plants are overflowing with the crustacean, causing prices to plummet.
10 Jul 2012:
Corals Facing Open Ocean
More Vulnerable to Warming, Study Finds
U.S. scientists say coral reef systems exposed to the open ocean are most vulnerable to warming ocean temperatures
. In a new study, researchers at the University of North Carolina write that three distinct coral zones located within the Mesoamerican Barrier Reef System in Central America — including the foreef (closest to the ocean), the nearshore (closest to the shore), and the backreef (directly behind the reef crest) — saw an increase in average summer sea surface temperatures from 1982 to 2008. But while they observed a decline in skeletal growth in corals facing the ocean during that period, coral growth rates in the other two zones remained relatively stable. According to their findings, published in the journal Nature Climate Change
, the ocean-facing corals were more vulnerable to warming conditions because historically they had experienced cooler and more stable seawater. “However, because backreef and nearshore coral colonies have historically been exposed to warmer and more variable seawater temperatures, they seem to be less affected,” said Karl Castillo, a postdoctoral researcher at UNC and lead author of the study.
09 Jul 2012:
Aquaculture Output To Rise
33 Percent Over Next Decade, UN Says
The global aquaculture sector could produce 33 percent more fish for human consumption over the next decade
, an increase in production that will help feed a growing world population even as fisheries are overexploited, a new UN report predicts. More than 79 million tons of farmed fish, crustaceans, mollusks and aquatic plants are expected to be produced from 2012 to 2012, a 33 percent growth compared with just a 3 percent growth from capture fisheries, according to the report from the UN’s Food and Agriculture Organization
. By 2018, the amount of fish raised in aquaculture will exceed the amount caught in the wild for the first time and will account for 52 percent of the total by 2021, the report states. This increased reliance on farm-raised fish comes as an increasing number of fisheries worldwide are exploited, with about 30 percent of fish stock now overexploited and another 57 percent fully exploited or very close to maximum sustainable production.
06 Jul 2012:
Coral Reef Systems Collapsed
During Earlier Changes to Climate
An increase in ocean temperatures that occurred 4,000 years ago triggered a collapse of coral reef systems in the eastern Pacific
that lasted for about 2,500 years, according to a new study. In an analysis of 17-foot core samples taken from the frameworks of coral reefs off the Panama coast, scientists from the Florida Institute of
Technology found that the reefs stopped growing during a period that coincided with the start of a period of dramatic swings in the El Nino-Southern Oscillation, including periods when ocean temperatures elevated significantly. They say this gap in growth also occurred in reef systems as far away as Japan and Australia. “For Pacific reefs to have collapsed for such a long time and over such a large geographic scale, they must have experienced a major climatic disturbance,” said Lauren Toth, a co-author of the study published in the journal Science
. While the scientists said the results may foretell similar catastrophic events for reef systems worldwide as ocean temperatures rise as a consequence of climate change, they noted that it also suggests that coral systems may have the resilience to rebound if climate change is mitigated or reversed.
02 Jul 2012:
Leatherback Turtle Declines
Will Escalate As Climate Warms, Study Finds
A warming climate could exacerbate threats facing leatherback turtle populations in the eastern Pacific Ocean, creating conditions that could trigger a 75 percent reduction in turtle numbers by the end of the century
, a new study says. Even under existing
conditions, turtle births ebb and flow each year, researchers say, with eggs and hatchlings more likely to survive in cooler, rainier seasons, and a greater number of male hatchlings occurring in predominantly female leatherback populations in these conditions. After modeling these population dynamics in light of projected changes in temperature and precipitation in the turtles’ critical nesting areas, particularly the beaches of Costa Rica, researchers from Drexel and Princeton universities projected an increase in egg and hatchling mortality. According to their findings, leatherback populations could decline 7 percent per decade through 2100. A key in preserving turtle populations in the future will be manipulating beach conditions to encourage as many good hatchlings as possible, the researchers say.
27 Jun 2012:
BP Oil Spill Accelerated
Erosion of Louisiana Marshlands
The 2010 BP oil spill hastened the loss of Louisiana’s already fragile salt marshlands
, a new study says. In a comparison of erosion rates at three healthy marsh sites and three areas affected by the oil spill, University of Florida scientists found
that oil from the spill coated thick grasses on the outer edge of some wetlands, killing off salt marsh plants 15 to 30 feet from the shoreline. When those grasses died, the deep roots that held the soil sediment died as well, causing the rate of erosion on shore banks to more than double. In Louisiana’s Barataria Bay, for instance, oiled marshes have receded nearly 10 feet per year after the spill — about twice the normal rate of erosion in a region already losing huge areas of marshland as a result of channelization of the Mississippi River and rising sea levels. “We already knew that erosion leads to permanent marsh loss, and now we know that oil can exacerbate it,” said Brian Silliman, a University of Florida biologist and lead author of the study, published in the Proceedings of the National Academy of Sciences
25 Jun 2012:
U.S. Atlantic Coast Already
‘Hotspot’ of Sea Level Rise, Study Says
A 600-mile stretch of the U.S. East Coast is experiencing rates of sea level rise that are three to four times greater than the global average
, according a new study. In a new analysis, scientists at the U.S. Geological Survey (USGS) found that sea levels from Boston, Mass. to Cape Hatteras, N.C. have risen 2 to 3.7 millimeters per year since 1990, compared with a global average of 0.6 to 1 millimeters per year. According to the study, published in the journal Nature Climate Change
, sea levels appear to be rising in this mid-Atlantic region because a major Atlantic current that carries tropical water to the north is slowing down; that warmth expands seawater, which can lead to higher sea levels. “Many people mistakenly think that the rate of sea level rise is the same everywhere as glaciers and ice caps melt… [but] as demonstrated in this study, regional oceanographic contributions must be taken into account
in planning for what happens to coastal property,” said Marcia McNutt, director of the USGS.