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Pollen Beneficial For Northern Lakes
Mark Graham, a PhD student from the Department of Biological Sciences at the U of A, has shown for the first time the benefits of pollen on boreal lakes. Rich in nutrients, pollen is an essential component of plant fertilization but few think of its importance to fertilize lakes. Wind-dispersed pollen in early summer is not only visually striking, but it can represent a substantial pulse of nutrients to northern lakes. Graham's research team found that plankton responded strongly to additions of pollen in experimental enclosures, located along the shorelines of three boreal lakes in northwestern Ontario's Experimental Lakes Area. "Specifically, pollen subsidized the lake water nutrient levels and in turn, promoted the abundance of plankton," said Graham, who is working with Dr. Rolf Vinebrooke in the U of A's Freshwater Biodiversity Laboratory. "Our findings strongly suggest that pollen is an important linkable between terrestrial and aquatic ecosystems in northern environments". By increasing the availability of plankton, an important food resource for forage fish, the production of harvestable sport fish may also rise, all thanks to pollen......... Posted by: Tyler Permalink Source Best Done Close to the Evolutionary Home
Berkeley Lab researchers Shyam Prabhakar (left) and Len Pennacchio have shown that location is the key to comparing evolutionarily conserved DNA sequences that regulate the expression of genes. Species that are close on the evolutionary tree are best.
"While one can compare distant vertebrates to humans and identify sequences that are highly evolutionarily conserved, such elements are few and far between," said Len Pennacchio, a geneticist with Berkeley Lab's Genomics Division and the head of JGI's genome analysis program. "In contrast, by comparing species that are more closely related, such as other mammals, we can find much more DNA sequence alignment." . Pennacchio and Shyam Prabhakar are the principal authors of a paper that appears in the recent issue of the publication Genome Research, which presents the results of a comparative genomics study that quantified the advantages of staying close to the evolutionary home. Other co-authors of the paper were Francis Poulin, Malak Shoukry, Veena Afzal, Edward Rubin and Olivier Couronne. When Mother Nature develops something that works, she tends to stick with it. Hence sequences of DNA that serve as protein-coding genes or enhancers that regulate the expression of those genes have been conserved through thousands of years of evolution. Gene hunters have capitalized on this tendency by comparing the DNA of different species to identify genes and determine their functions. For example, the genome of the Fugu fish contains essentially the same genes as the human genome but carries them in approximately 400 million bases as compared to the three billion bases that make up human DNA......... Posted by: William Permalink Source Most-detailed Data Yet About Atmospheric Particles
CALIPSO, the fourth satellite in the so-called "A-Train" constellation, follows just a few seconds behind Cloudsat, the satellite it was launched with on April 28. The group of six climate research satellites crosses the equator from north to south at 1:30 p.m. local time on each orbit.
For University of Washington atmospheric researchers Robert Charlson and Theodore Anderson, co-researchers on the CALIPSO satellite's science team, there are two key parts to the research: determining the effects of aerosols on climate in cloudy skies and in clear skies. "Much of the Earth is covered by broken clouds. If you look down at any big patch of clouds, often you will see that it is really made up of broken clouds," said Charlson, a UW atmospheric sciences professor. "That suggests that there could be an intermediate state between clear and cloudy conditions that has a considerable effect on climate, and it appears to be very sensitive to changes in aerosol levels." Aerosols are tiny particles suspended in the air, such as bits of dusty ash from volcanoes, smoke and haze from combustion, soil dust from desert storms and salt from evaporating sea spray. They float in the atmosphere, absorbing some sunlight and reflecting some back into space, but no one knows just how much effect they have globally. Charlson and Anderson say that remains one of the biggest unanswered questions about human-induced climate change......... Posted by: Brooke Permalink Source Surviving Snow
Terrestrial options for early climate
New research shows organisms called eukaryotes - organisms of one or more complex cells that engage in sexual reproduction and are ancestors of the animal and plant species present today - existed 50 million to 100 million years before that ice age and somehow did survive. The work also shows that the cyanobacteria, or blue-green bacteria, that put the oxygen in the atmosphere in the first place, apparently were pumping out oxygen for millions of years before that, and also survived Earth's glaciation. The findings call into question the direst models of just how deep the deep freeze was, said University of Washington astrobiologist Roger Buick, a professor of Earth and space sciences. While the ice likely was widespread, it probably was not consistently as thick as a half-mile, he said. "That kind of ice coverage chokes off photosynthesis, so there's no food for anything, especially eukaryotes. They just couldn't survive," he said. "But this research shows they did survive."........ Posted by: Ashley Permalink Source The Oldest Portrait On Record
The 27,000-year-old work was found by a local pensioner, Gerard Jourdy, in the Vilhonneur grotto near Angoulême. Drawn with calcium carbonate, and using the bumps in the wall to give form to the face, it features two horizontal lines for the eyes, another for the mouth and a vertical line for the nose. "The portrait of this face is unique," said Jean Airvaux, a researcher at the French Directorate of Cultural Affairs. "We have other drawings, but they are more recent. Here, it could be the oldest representation of a human face."........ Posted by: William Permalink Source Top 100 Ecological Questions
Image courtesy of http://telematics.ex.ac.uk/
As per the lead author, Professor Bill Sutherland of the University of East Anglia: "There is currently too little information flow between researchers and policy makers. Narrowing this gap would be very beneficial in generating policies that are based on sound science. On the other hand, it is desirable that research should be more clearly directed at issues that influence policy." The list of 100 questions is the outcome of two days of discussion between 654 environmental policy makers and academics. The academics acted as facilitators, helping the policy makers arrive at a short-list of 100 key questions from an initial long-list of more than 1,000. Policy makers came from 30 leading environmental organisations and regulators, including the Environment Agency, SEPA, English Nature, the National Trust, Butterfly Conservation, the Wildlife Trusts, the Woodland Trust and the British Trust for Ornithology, and the short-list was agreed by consensus and compromise......... Posted by: Tyler Permalink Source Human Activities And Ecological Patterns
The role of human activities in shaping ecological patterns at continental and global spatial scales has been understudied. This is due in part to the assumption that these large-scale patterns are generated primarily through non-human processes. A study in a forthcoming issue of the Journal of Biogeography, using data on breeding bird assemblages in North America from 1968 to 2003, finds evidence suggesting that human activities have played a role in shaping large-scale ecological patterns. Dr. Frank La Sorte from New Mexico State University used several novel analytical approaches to examine bird assemblages and their geographic ranges in North America to test for patterns of change over time. His findings suggest that a majority of bird species within these assemblages experienced geographic range expansion and a majority of bird assemblages experienced an increased abundance of common species over the 36 year time period. Overall, the results indicate that common species have become more prevalent across bird assemblages in North America within recent human history and human activities, therefore, cannot be ignored as a possible causal factor when assessing these patterns......... Posted by: William Permalink Source Surviving The Snowball Earth
New research shows organisms called eukaryotes -- organisms of one or more complex cells that engage in sexual reproduction and are ancestors of the animal and plant species present today -- existed 50 million to 100 million years before that ice age and somehow did survive. The work also shows that the cyanobacteria, or blue-green bacteria, that put the oxygen in the atmosphere in the first place, apparently were pumping out oxygen for millions of years before that, and also survived Earth's glaciation. The findings call into question the direst models of just how deep the deep freeze was, said University of Washington astrobiologist Roger Buick, a professor of Earth and space sciences. While the ice likely was widespread, it probably was not consistently as thick as a half-mile, he said. "That kind of ice coverage chokes off photosynthesis, so there's no food for anything, especially eukaryotes. They just couldn't survive," he said. "But this research shows they did survive."........ Posted by: William Permalink Source New Orleans Sinking Faster
Satellite images reveal that some areas of the city have been sinking at the rate of 1 inch (2.5 centimeters) a year. The findings, reported in the current issue of the journal Nature, may shed new light on the failure of the city's levee system and the flooding that followed Hurricane Katrina last August. A scientific team used one of Canada's RADARSAT satellites to map New Orleans and found that most of the city sank about a quarter inch (0.06 centimeter) annually in the three years leading up to Katrina's landfall. But a number of areas, including some of the levees designed to hold back the waters of the Gulf of Mexico, sank at four or five times that rate. "What we found is that some of the levee failures in New Orleans were [in] places where subsidence was highest," University of Miami geophysicist Tim Dixon told the Reuters news service. The data suggest that some levees could be 3 feet (0.9 meter) lower than when they were built some 40 years ago. The Mississippi River Gulf Outlet-the levee-protected canal notorious for its role in the flooding that followed Hurricane Katrina-has sunk more than three feet, the team's study reveals......... Posted by: Tyler Permalink Source Climate Is Made In A Greenhouse World
The scientists focus their interest on the causal relationships and feedbacks between the tropics and higher latitudes. Using marine geological records and data from global paleoclimate simulations they identify a previously unrecognized link between higher latitude climate dynamics and tropical African climate, the latter leading to exceptionally high burial of organic carbon in the deep tropical Atlantic. Marine geological record show that enhanced burial of organic carbon in the deep sea was confined to short time envelops of about 5 thousand years that reoccurred over millions of years at a regular pattern (see Beckmann and co-workers, published 8 September 2005 in Nature 437). Climate modelling is one key technique to identify and understand the larger-scale mechanisms that result in geological evidence. By varying one of Earth's orbital parameters, the precession of the equinoxes, the modelling setup used in this study provides new insights to the dynamics of global climate during past greenhouse conditions. Accordingly, changes in the amount of energy approaching the top of the atmosphere, called "insolation", finally triggered cyclic variations of the tropical water cycle in tropical Africa. Periods of enhanced precipitation and freshwater runoff then resulted in massive burial of organic carbon at the sea floor suggesting that processes in the atmosphere drive changes in the ocean. The remaining, fundamental question on the source area(s) where cyclic fluctuations in tropical water cycling and marine carbon burial were triggered was addressed using global climate simulation. Applying four different orbital configurations of one complete precession cycle the model identifies cross-latitudinal variations of atmospheric pressure systems, fluctuations in the magnitude and direction of surface winds, and associated precipitation and runoff patterns. Previously unrecognized, the model identifies the strongest variations in atmospheric pressure above the South Atlantic at mid-southern latitudes between 25-55 degree S. Establishment of an atmospheric telecorrelation between this area and tropical Africa, however, is limited to one specific orbital configuration, which lasted for about 5 thousand years and caused strongest climate contrasts in a seasonal cycle......... Posted by: Tyler Permalink Source |
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