It's not easy being a fish these days, but it could be even harder being a crab. Research into marine "dead zones" around the world suggests that crustaceans are the first to gasp for air when oxygen levels get low.
The findings, based on a review of 872 published studies of 206 ocean-floor dwelling species, also suggest that a much greater area than we thought is dangerously low on oxygen.
In marine dead zones - also known as hypoxic zones - the amount of dissolved oxygen in the water becomes too low for organisms to survive.
They are usually caused by synthetic fertilisers, which are carried from fields, down rivers, and out to sea, where algal blooms gorge on the extra nutrients. When these phytoplankton die, they fall to the bottom where they are eaten by bacteria that consume all the local oxygen in the process.
Marine biologists generally hold that any area that has less than 2 milligrams of dissolved oxygen per litre of seawater is hypoxic - "dead". The threshold was set by a study in 1983 in the Gulf of Mexico, when marine biologists found that fish and shrimp had deserted bottom waters that had 2 mg/l of oxygen or less.
Animals
Cancun, Mexico - Dainty blue fish dart around coral shaped like moose antlers near the Mexican resort of Cancun, but sickly brown spots are appearing where pollution threatens one of the world's largest reefs.
Parts of the reef, nestled in turquoise waters, have died and algae -- which feed on sewage residues flowing out of the fast-growing resort city -- has taken over.
Coral reefs like Chitales, near the northern tip of a Caribbean reef chain stretching from Mexico to Honduras, are dying around the world as people and cities put more stress on the environment.
Climate change alone could trigger a global coral die-off by 2100 because carbon emissions warm oceans and make them more acidic, according to a study published in December.
But local environmental problems like sewage, farm runoff and overfishing could kill off much of the world's reefs decades before global warming does, said Roberto Iglesias, a biologist from UNAM university's marine sciences station near Cancun.
"The net effect of pollution is as bad or maybe worse than the effects of global warming," said Iglesias, a co-author of the study in the journal Science on how climate change affects reefs.
Human waste like that from Cancun's hotels and night spots aggravates threats to coral worldwide like overzealous fishing which hurts stocks of fish that eat reef-damaging algae.
Parts of the reef, nestled in turquoise waters, have died and algae -- which feed on sewage residues flowing out of the fast-growing resort city -- has taken over.
Coral reefs like Chitales, near the northern tip of a Caribbean reef chain stretching from Mexico to Honduras, are dying around the world as people and cities put more stress on the environment.
Climate change alone could trigger a global coral die-off by 2100 because carbon emissions warm oceans and make them more acidic, according to a study published in December.
But local environmental problems like sewage, farm runoff and overfishing could kill off much of the world's reefs decades before global warming does, said Roberto Iglesias, a biologist from UNAM university's marine sciences station near Cancun.
"The net effect of pollution is as bad or maybe worse than the effects of global warming," said Iglesias, a co-author of the study in the journal Science on how climate change affects reefs.
Human waste like that from Cancun's hotels and night spots aggravates threats to coral worldwide like overzealous fishing which hurts stocks of fish that eat reef-damaging algae.
Mountain pine beetles appear to be doing more than killing large swaths of forests in the Rocky Mountains. Scientists suspect they are also altering local weather patterns and air quality.
A new international field project, led by scientists at the National Center for Atmospheric Research (NCAR), is exploring how trees and other vegetation influence rainfall, temperatures, smog, and other aspects of the atmosphere. Plants take in and emit chemicals that affect the air, and they also absorb varying amounts of incoming heat from the Sun. When portions of a forest die, the local atmosphere can change in subtle ways.
"Forests help control the atmosphere, and there's a big difference between the impacts of a living forest and a dead forest," says NCAR scientist Alex Guenther, a principal investigator on the project. "With a dead forest, we may get different rainfall patterns, for example."
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| ©Carlye Calvin, UCAR |
| Mountain pine beetles have killed large numbers of trees in the Rockies. |
A new international field project, led by scientists at the National Center for Atmospheric Research (NCAR), is exploring how trees and other vegetation influence rainfall, temperatures, smog, and other aspects of the atmosphere. Plants take in and emit chemicals that affect the air, and they also absorb varying amounts of incoming heat from the Sun. When portions of a forest die, the local atmosphere can change in subtle ways.
"Forests help control the atmosphere, and there's a big difference between the impacts of a living forest and a dead forest," says NCAR scientist Alex Guenther, a principal investigator on the project. "With a dead forest, we may get different rainfall patterns, for example."
Billings, MT - Federal wildlife officials have asked a judge to put gray wolves in the Northern Rockies back on the endangered species list - a sharp reversal from the government's prior contention that the animals were thriving.
Attorneys for the Fish and Wildlife Service asked U.S. District Judge Donald Molloy in Missoula to vacate the agency's February finding that more than 1,400 wolves in the region no longer needed federal protection.
The government's request Monday follows a July injunction in which Molloy had blocked plans for public wolf hunts this fall in Montana, Wyoming and Idaho pending resolution of a lawsuit by environmentalists.
"What we want to do is look at this more thoroughly," Fish and Wildlife spokeswoman Sharon Rose said. "We definitely have a lot of wolves out there, but we need to address some of (Molloy's) concerns in a way that people feel comfortable with."
At issue is whether a decade-long wolf restoration program has reversed the near-extermination of wolves, or if - as environmentalists claim - their long-term survival remains in doubt due to proposed hunting.
Attorneys for the Fish and Wildlife Service asked U.S. District Judge Donald Molloy in Missoula to vacate the agency's February finding that more than 1,400 wolves in the region no longer needed federal protection.
The government's request Monday follows a July injunction in which Molloy had blocked plans for public wolf hunts this fall in Montana, Wyoming and Idaho pending resolution of a lawsuit by environmentalists.
"What we want to do is look at this more thoroughly," Fish and Wildlife spokeswoman Sharon Rose said. "We definitely have a lot of wolves out there, but we need to address some of (Molloy's) concerns in a way that people feel comfortable with."
At issue is whether a decade-long wolf restoration program has reversed the near-extermination of wolves, or if - as environmentalists claim - their long-term survival remains in doubt due to proposed hunting.
The populations of the world's common birds are declining as a result of continued habitat loss, a global assessment has warned.
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| ©Gareth Peacock |
| Once a familiar sight and sound, the nightingale is becoming less common |
A new iguana has been discovered in the central regions of Fiji. The colorful new species, named Brachylophus bulabula, joins only two other living Pacific iguana species, one of which is critically endangered. The scientific name bulabula is a doubling of bula, the Fijian word for 'hello,' offering an even more enthusiastic greeting.
Pacific iguanas have almost disappeared as the result of human presence. Two species were eaten to extinction after people arrived nearly 3,000 years ago. The three living Brachylophus iguana species face threats from loss and alteration of their habitat, as well as from feral cats, mongooses and goats that eat iguanas or their food source.
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| ©Paddy Ryan, Ryan Photographic |
| Brachylophus bulabula. |
Pacific iguanas have almost disappeared as the result of human presence. Two species were eaten to extinction after people arrived nearly 3,000 years ago. The three living Brachylophus iguana species face threats from loss and alteration of their habitat, as well as from feral cats, mongooses and goats that eat iguanas or their food source.
Uttar Pradesh forest authorities are at a loss to explain the mysterious deaths of 14 black bucks in Agra and Kanpur districts of the state.
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| ©Avinash K J |
Hundreds of new kinds of animal species surprised international researchers systematically exploring waters off two islands on the Great Barrier Reef and a reef off northwestern Australia -- waters long familiar to divers.
The expeditions, affiliated with the global Census of Marine Life, help mark the International Year of the Reef and included the first systematic scientific inventory of spectacular soft corals, named octocorals for the eight tentacles that fringe each polyp.
The explorers have released some initial results and stunning images from their landmark four-year effort to record the diversity of life in and around Australia's renowned reefs.
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| ©Gary Cranitch, Queensland Museum, 2008 |
| Ctenophore, or comb jelly, collected off Wassteri Reef, Heron Island. |
The expeditions, affiliated with the global Census of Marine Life, help mark the International Year of the Reef and included the first systematic scientific inventory of spectacular soft corals, named octocorals for the eight tentacles that fringe each polyp.
The explorers have released some initial results and stunning images from their landmark four-year effort to record the diversity of life in and around Australia's renowned reefs.
A new species of blind, subterranean, predatory ant discovered in the Amazon rainforest by University of Texas at Austin evolutionary biologist Christian Rabeling is likely a descendant of the very first ants to evolve.
The new ant is named Martialis heureka, which translates roughly to "ant from Mars," because the ant has a combination of characteristics never before recorded. It is adapted for dwelling in the soil, is two to three millimeters long, pale, and has no eyes and large mandibles, which Rabeling and colleagues suspect it uses to capture prey.
The ant also belongs to its own new subfamily, one of 21 subfamilies in ants. This is the first time that a new subfamily of ants with living species has been discovered since 1923 (other new subfamilies have been discovered from fossil ants).
Rabeling says his discovery will help biologists better understand the biodiversity and evolution of ants, which are abundant and ecologically important insects.
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| ©Christian Rabeling, the University of Texas at Austin |
| This new species of blind, subterranean, predatory ant, Martialis heureka, was discovered in the Amazon by Christian Rabeling at the University of Texas at Austin. It belongs to the first new subfamily of living ants discovered since 1923, and is a descendant of one of the first ant lineages to evolve over 120 million years ago. |
The new ant is named Martialis heureka, which translates roughly to "ant from Mars," because the ant has a combination of characteristics never before recorded. It is adapted for dwelling in the soil, is two to three millimeters long, pale, and has no eyes and large mandibles, which Rabeling and colleagues suspect it uses to capture prey.
The ant also belongs to its own new subfamily, one of 21 subfamilies in ants. This is the first time that a new subfamily of ants with living species has been discovered since 1923 (other new subfamilies have been discovered from fossil ants).
Rabeling says his discovery will help biologists better understand the biodiversity and evolution of ants, which are abundant and ecologically important insects.
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| ©Unknown |
Scientists at the Norwegian Polar Institute reported Thursday that the tiny Arctic ivory gull has the highest known concentrations of PCBs, chemicals long used in the pesticide DDT along with plastics, paints and other products.
The gull has set a new record as the bird most contaminated by the two prohibited toxins, the scientists said.
There are currently about 14,000 ivory gulls, which inhabit areas from Canada to Siberia. The current research was conducted following reports that the number of ivory gulls had plummeted 80 percent in Canada.
