[Today's Newspaper] from [Los Angeles Times]
[U.S. & World > Environment]
Associated Press
January 10, 2010
Northwest orcas rebound, but still endangered
Six births bump up the population of killer whales off Washington and southwest British Columbia. Keeping the number up will be hard, experts say.
Seattle - A little over a year after researchers feared a drop in the Northwest's endangered killer-whale population meant disaster, the number of orcas has bounced back with six new babies and no whales lost.
Though scientific evidence is skimpy, some whale experts say the good news might be the result of enough salmon for the black-and-white mammals to eat. Others say so little is known about orcas that the baby boom could be a result of any number of factors -- or simply a statistical fluke.
Whatever the reason, they're overjoyed about the new arrivals.
"We're all very happy to see so many births," said Susan Berta of the Whidbey Island-based Orca Network.
"We're all hoping that they find lots of fish to keep them healthy and keep the mothers in good condition so they can feed the calves," she said.
The Center for Whale Research says that in 2008, eight orcas in the three pods, J, K and L, that make up the southern resident population in Washington and southwest British Columbia went missing and were presumed dead, including two females of reproductive age and the 98-year-old matriarch of K Pod. With just one surviving birth that year, the total in the three pods as of December 2008 dropped to 82.
That alarmed researchers. "This is a disaster," Ken Balcomb, a senior scientist at the San Juan Island-based center, said in October of that year.
But in 2009, no deaths were reported and five new calves were spotted, giving a December total of 87. A sixth infant was born Jan. 3 while its family, J Pod, was near Seattle on a winter visit, making it 88.
Balcomb and Howard Garrett, director of the Orca Network, think food might have something to do with it.
The whales feed on salmon -- particularly chinook salmon, the largest and arguably tastiest of the Pacific species. Chinooks are listed as threatened or endangered in several Northwest waterways, including Puget Sound and the Columbia River.
"Unfortunately, [the whales are] very picky," Garrett said, with chinooks sometimes making up 80% of their diet. It sounds simplistic, Garrett said, but "the way that we can tag the population fluctuations is directly from the chinook runs."
Taken as a whole, the runs in the region have held steady over at least the last two years, he said.
It's not that simple, said Brad Hanson, a wildlife biologist with the federal Northwest Fisheries Science Center in Seattle. He said that for much of the year, little is known about what salmon stocks the whales eat and where.
The southern orcas can travel widely, from the north end of Canada's Vancouver Island to Northern California for the K and L pods.
Depending on the river, he said, some salmon stocks are up, some down, some about average. And orcas face the same problem that bedevils all fishermen: hitting the right run at the right time under the right conditions.
"There's just so many different variables involved," Hanson said.
The three pods in the southern resident community -- J Pod based in the San Juan Islands, K Pod in the Strait of Juan de Fuca, and L Pod off the coast -- are genetically and behaviorally distinct from other killer whales. Besides sticking to this region, their sounds are considered a unique dialect, they tend to mate only within their community, and they usually gather each year to socialize in a "super pod" near the San Juans.
Orcas have a 17-month gestation period, so at least six of the whales were pregnant a year ago. From a distance it's hard to tell whether an orca is pregnant, so no one on land knew they were expecting when worries over the lost whales emerged.
Over the years, the Center for Whale Research has tracked the southern population, and the numbers have varied from a low of 71 in 1977 to a high of 97 in 1996. The current total of 88, which matches the total in 2007, is far below the 140 or so that lived here before dozens were captured for aquariums and parks in the 1960s and early '70s.
After a 20% drop in their numbers in the late 1990s, blamed by many on pollution and dwindling salmon stocks, the southern resident orcas were listed as an endangered species in 2005. Experts estimate a long-term steady population of about 200 would be needed to take them off the list.
Experts caution that one good year isn't a recovery. Young orcas have a rough life -- commonly, about 50% die in their first year, they say. Crucial to their long-term survival, the experts say, will be cleaning up the marine environment and eliminating the toxic chemicals that collect in the whales' bodies and restoring the region's once-massive salmon runs.
Still, Balcomb said: "I'm just optimistic that this year's bumper crop of babies will prove to be their investment in the future."
[Nation > Science]
By Amina Khan
January 9, 2010
Sierra's current height goes back 50 million years, study finds
The finding adds to a growing body of evidence that the mountain range is much older than previously believed, and has implications for evolutionary studies.
The Sierra Nevada reached their present height 50 million years ago -- 30 million years earlier than geologists once believed, according to a new study.
The research, part of a growing body of evidence that the Sierra Nevada are far older than once thought, has implications for understanding the evolution of the plants and animals in the West, as well as the likely climate of ancient North America.
The study, by scientists at Yale University and the Berkeley Museum of Paleontology, used 50 million-year-old chemical traces left on ancient leaves by microbes and raindrops to calculate the new height estimate for the Sierras at that time.
The western United States would have looked very different then, filled with lush forests of vines and magnolias. The Pacific Ocean would have lapped the foot of the Sierra.
"This is a time period where there would have been crocodiles in Wyoming," said lead author Michael Hren, a University of Michigan postdoctoral fellow who did the research while at Yale.
Sampling ancient flood-plain sites, the researchers found leaves preserved in the oxygen-poor sediments. They analyzed the waxes on the surface of those ancient leaves, measuring levels of normal hydrogen and its slightly heavier isotope, deuterium. This gave them an estimate of the elevation at which the leaves grew.
As clouds rise up the side of mountains, water droplets containing the heavier deuterium fall first, and droplets containing the lighter hydrogen later. The lower the proportion of deuterium on a leaf, the higher up the mountain that leaf must have been, the scientists surmised.
Hren also looked at soil carried down from the mountains to the ancient flood plains, checking for chemicals left by microbes that lived in the sediments. Cell membranes in these microorganisms changed composition depending on whether it was cool or hot -- providing a kind of ancient biological thermometer.
Using those data, the scientists estimated that the temperature had been 6 to 8 degrees Celsius warmer than today.
The idea that the Sierra Nevada were sitting at their current height 30 million years earlier than anticipated has implications for studies on the evolution of plants and animals, scientists said.
For example, with the mountains already in place so long ago, "how could animals migrate from California into the Great Basin?" asked Paul Koch, chairman of the Earth and Planetary Sciences Department at UC Santa Cruz, who was not involved in the research.
For understanding evolution of U.S. flora and fauna, "it matters a lot," he said.
The finding also has implications for historical climate estimates across North America. "Climate models require that you understand elevation," Koch said. "In Kansas it matters for you to get the topography of the Sierra Nevada right. In Florida it matters."
The study, published in the journal Geology, also provides a more accurate tool for exploring the elevation of ancient landscapes, said Diane M. Erwin, a study coauthor from the UC Berkeley Museum of Paleontology. In the past, such estimates have been made by studying leaf shapes. Such estimates can be less accurate than the deuterium method.
Putting together different pieces of data to create a coherent picture of the past is what drew him to the work, Hren said.
"It's amazing to break open a rock and look at these amazingly preserved leaves that can tell you a story from 50 million years ago."
[U.S. & World > Environment]
Associated Press
January 10, 2010
Northwest orcas rebound, but still endangered
Six births bump up the population of killer whales off Washington and southwest British Columbia. Keeping the number up will be hard, experts say.
Seattle - A little over a year after researchers feared a drop in the Northwest's endangered killer-whale population meant disaster, the number of orcas has bounced back with six new babies and no whales lost.
Though scientific evidence is skimpy, some whale experts say the good news might be the result of enough salmon for the black-and-white mammals to eat. Others say so little is known about orcas that the baby boom could be a result of any number of factors -- or simply a statistical fluke.
Whatever the reason, they're overjoyed about the new arrivals.
"We're all very happy to see so many births," said Susan Berta of the Whidbey Island-based Orca Network.
"We're all hoping that they find lots of fish to keep them healthy and keep the mothers in good condition so they can feed the calves," she said.
The Center for Whale Research says that in 2008, eight orcas in the three pods, J, K and L, that make up the southern resident population in Washington and southwest British Columbia went missing and were presumed dead, including two females of reproductive age and the 98-year-old matriarch of K Pod. With just one surviving birth that year, the total in the three pods as of December 2008 dropped to 82.
That alarmed researchers. "This is a disaster," Ken Balcomb, a senior scientist at the San Juan Island-based center, said in October of that year.
But in 2009, no deaths were reported and five new calves were spotted, giving a December total of 87. A sixth infant was born Jan. 3 while its family, J Pod, was near Seattle on a winter visit, making it 88.
Balcomb and Howard Garrett, director of the Orca Network, think food might have something to do with it.
The whales feed on salmon -- particularly chinook salmon, the largest and arguably tastiest of the Pacific species. Chinooks are listed as threatened or endangered in several Northwest waterways, including Puget Sound and the Columbia River.
"Unfortunately, [the whales are] very picky," Garrett said, with chinooks sometimes making up 80% of their diet. It sounds simplistic, Garrett said, but "the way that we can tag the population fluctuations is directly from the chinook runs."
Taken as a whole, the runs in the region have held steady over at least the last two years, he said.
It's not that simple, said Brad Hanson, a wildlife biologist with the federal Northwest Fisheries Science Center in Seattle. He said that for much of the year, little is known about what salmon stocks the whales eat and where.
The southern orcas can travel widely, from the north end of Canada's Vancouver Island to Northern California for the K and L pods.
Depending on the river, he said, some salmon stocks are up, some down, some about average. And orcas face the same problem that bedevils all fishermen: hitting the right run at the right time under the right conditions.
"There's just so many different variables involved," Hanson said.
The three pods in the southern resident community -- J Pod based in the San Juan Islands, K Pod in the Strait of Juan de Fuca, and L Pod off the coast -- are genetically and behaviorally distinct from other killer whales. Besides sticking to this region, their sounds are considered a unique dialect, they tend to mate only within their community, and they usually gather each year to socialize in a "super pod" near the San Juans.
Orcas have a 17-month gestation period, so at least six of the whales were pregnant a year ago. From a distance it's hard to tell whether an orca is pregnant, so no one on land knew they were expecting when worries over the lost whales emerged.
Over the years, the Center for Whale Research has tracked the southern population, and the numbers have varied from a low of 71 in 1977 to a high of 97 in 1996. The current total of 88, which matches the total in 2007, is far below the 140 or so that lived here before dozens were captured for aquariums and parks in the 1960s and early '70s.
After a 20% drop in their numbers in the late 1990s, blamed by many on pollution and dwindling salmon stocks, the southern resident orcas were listed as an endangered species in 2005. Experts estimate a long-term steady population of about 200 would be needed to take them off the list.
Experts caution that one good year isn't a recovery. Young orcas have a rough life -- commonly, about 50% die in their first year, they say. Crucial to their long-term survival, the experts say, will be cleaning up the marine environment and eliminating the toxic chemicals that collect in the whales' bodies and restoring the region's once-massive salmon runs.
Still, Balcomb said: "I'm just optimistic that this year's bumper crop of babies will prove to be their investment in the future."
[Nation > Science]
By Amina Khan
January 9, 2010
Sierra's current height goes back 50 million years, study finds
The finding adds to a growing body of evidence that the mountain range is much older than previously believed, and has implications for evolutionary studies.
The Sierra Nevada reached their present height 50 million years ago -- 30 million years earlier than geologists once believed, according to a new study.
The research, part of a growing body of evidence that the Sierra Nevada are far older than once thought, has implications for understanding the evolution of the plants and animals in the West, as well as the likely climate of ancient North America.
The study, by scientists at Yale University and the Berkeley Museum of Paleontology, used 50 million-year-old chemical traces left on ancient leaves by microbes and raindrops to calculate the new height estimate for the Sierras at that time.
The western United States would have looked very different then, filled with lush forests of vines and magnolias. The Pacific Ocean would have lapped the foot of the Sierra.
"This is a time period where there would have been crocodiles in Wyoming," said lead author Michael Hren, a University of Michigan postdoctoral fellow who did the research while at Yale.
Sampling ancient flood-plain sites, the researchers found leaves preserved in the oxygen-poor sediments. They analyzed the waxes on the surface of those ancient leaves, measuring levels of normal hydrogen and its slightly heavier isotope, deuterium. This gave them an estimate of the elevation at which the leaves grew.
As clouds rise up the side of mountains, water droplets containing the heavier deuterium fall first, and droplets containing the lighter hydrogen later. The lower the proportion of deuterium on a leaf, the higher up the mountain that leaf must have been, the scientists surmised.
Hren also looked at soil carried down from the mountains to the ancient flood plains, checking for chemicals left by microbes that lived in the sediments. Cell membranes in these microorganisms changed composition depending on whether it was cool or hot -- providing a kind of ancient biological thermometer.
Using those data, the scientists estimated that the temperature had been 6 to 8 degrees Celsius warmer than today.
The idea that the Sierra Nevada were sitting at their current height 30 million years earlier than anticipated has implications for studies on the evolution of plants and animals, scientists said.
For example, with the mountains already in place so long ago, "how could animals migrate from California into the Great Basin?" asked Paul Koch, chairman of the Earth and Planetary Sciences Department at UC Santa Cruz, who was not involved in the research.
For understanding evolution of U.S. flora and fauna, "it matters a lot," he said.
The finding also has implications for historical climate estimates across North America. "Climate models require that you understand elevation," Koch said. "In Kansas it matters for you to get the topography of the Sierra Nevada right. In Florida it matters."
The study, published in the journal Geology, also provides a more accurate tool for exploring the elevation of ancient landscapes, said Diane M. Erwin, a study coauthor from the UC Berkeley Museum of Paleontology. In the past, such estimates have been made by studying leaf shapes. Such estimates can be less accurate than the deuterium method.
Putting together different pieces of data to create a coherent picture of the past is what drew him to the work, Hren said.
"It's amazing to break open a rock and look at these amazingly preserved leaves that can tell you a story from 50 million years ago."
※コメント投稿者のブログIDはブログ作成者のみに通知されます