Tag Archives: human activities

NASA iPad App Shows Earth Changing Before Your Eyes

Human activities, a changing climate and natural disasters are rapidly altering the face of our planet. Now, with NASA’s Images of Change iPad application, users can get an interactive before-and-after view of these changes.

The app presents pairs or sets of images of places around the world that have changed dramatically. Some of these locations have suffered a disaster, such as a fire or tsunami, or illustrate the effects of human activities, such as dam building or urban growth. Others document impacts of climate change such as persistent drought and rapidly receding glaciers. (more…)

Read More

Tropical forest carbon absorption may hinge on an odd couple

A unique housing arrangement between a specific group of tree species and a carbo-loading bacteria may determine how well tropical forests can absorb carbon dioxide from the atmosphere, according to a Princeton University-based study. The findings suggest that the role of tropical forests in offsetting the atmospheric buildup of carbon from fossil fuels depends on tree diversity, particularly in forests recovering from exploitation.

Tropical forests thrive on natural nitrogen fertilizer pumped into the soil by trees in the legume family, a diverse group that includes beans and peas, the researchers report in the journal Nature. The researchers studied second-growth forests in Panama that had been used for agriculture five to 300 years ago. The presence of legume trees ensured rapid forest growth in the first 12 years of recovery and thus a substantial carbon “sink,” or carbon-storage capacity. Tracts of land that were pasture only 12 years before had already accumulated as much as 40 percent of the carbon found in fully mature forests. Legumes contributed more than half of the nitrogen needed to make that happen, the researchers reported. (more…)

Read More

Study investigates extraordinary trout with tolerance to heavily polluted water

New research from the University of Exeter and King’s College London has shown how a population of brown trout can survive in the contaminated waters of the River Hayle in Cornwall where metal concentrations are so high they would be lethal to fish from unpolluted sites.

The team believe this is due to changes in the expression of their genes. The research was funded by NERC and the Salmon and Trout Association.

The researchers compared the trout living in the River Hayle with a population living in a relatively clean site in the River Teign. The results showed that the accumulation of metals in the kidney and liver – where metals are stored and detoxified – were 19 and 34 times higher in the  Hayle trout, respectively. In the gill, concentrations averaging 63 times higher were present in the Hayle fish, but there were no differences in metal content in the gut. This accumulation of metals in the Hayle fish highlights their extraordinary tolerance of the extreme metal concentrations in their environment. (more…)

Read More

Boat noise stops fish finding home

Boat noise disrupts orientation behaviour in larval coral reef fish, according to new research from the Universities of Exeter, Bristol and Liège.

Reef fish are normally attracted by reef sound but the study, conducted in French Polynesia, found that fish are more likely to swim away from recordings of reefs when boat noise is added.

Co-author, Dr Steve Simpson, a marine biologist at the University of Exeter, said: “Boat noise may scare fish, affecting their ecology.  Since one in five people in the world rely on fish as their major source of protein, regulating traffic noise in important fisheries areas could help marine communities and the people that depend on them.” (more…)

Read More

Century-Old Science Helps Confirm Global Warming

A new NASA and university analysis of ocean data collected more than 135 years ago by the crew of the HMS Challenger oceanographic expedition provides further confirmation that human activities have warmed our planet over the past century.

Researchers from the University of Tasmania, Sandy Bay, Australia; and NASA’s Jet Propulsion Laboratory, Pasadena, Calif., combined the ship’s measurements of ocean temperatures with modern observations from the international Argo array of ocean profiling floats. They used both as inputs to state-of-the-art climate models, to get a picture of how the world’s oceans have changed since the Challenger’s voyage. (more…)

Read More

New Research Will Help Shed Light on Role of Amazon Forests in Global Carbon Cycle

Berkeley Lab scientists devise new tools for detecting previously unknown tree mortality.

The Earth’s forests perform a well-known service to the planet, absorbing a great deal of the carbon dioxide pollution emitted into the atmosphere from human activities. But when trees are killed by natural disturbances, such as fire, drought or wind, their decay also releases carbon back into the atmosphere, making it critical to quantify tree mortality in order to understand the role of forests in the global climate system. Tropical old-growth forests may play a large role in this absorption service, yet tree mortality patterns for these forests are not well understood.

Now scientist Jeffrey Chambers and colleagues at the U.S. Department of Energy’s (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab) have devised an analytical method that combines satellite images, simulation modeling and painstaking fieldwork to help researchers detect forest mortality patterns and trends. This new tool will enhance understanding of the role of forests in carbon sequestration and the impact of climate change on such disturbances. (more…)

Read More

Nitrogen From Humans Pollutes Remote Lakes For More Than A Century

Nitrogen derived from human activities has polluted lakes throughout the Northern Hemisphere for more than a century and the fingerprint of these changes is evident even in remote lakes located thousands of miles from the nearest city, industrial area or farm.

The findings, published in the journal Science Dec. 16, are based on historical changes in the chemical composition of bottom deposits in 36 lakes using an approach similar to aquatic archeology. More than three quarters of the lakes, ranging from the U.S. Rocky Mountains to northern Europe, showed a distinctive signal of nitrogen released from human activities before the start of the 20th century, said Gordon Holtgrieve, a postdoctoral researcher at University of Washington School of Aquatic and Fishery Sciences and lead author of the report. The UW and a dozen other research institutions contributed to the research. (more…)

Read More

West Nile Virus Transmission Linked with Land-Use Patterns and “Super-spreaders”

*Spread highest in urbanized and agricultural habitats*

After its initial appearance in New York in 1999, West Nile virus spread across the United States in just a few years and is now well established throughout North and South America.

Both the mosquitoes that transmit it and the birds that are important hosts for the virus are abundant in areas that have been modified by human activities.

As a result, transmission of West Nile virus is highest in urbanized and agricultural habitats. (more…)

Read More