On trail of house sparrows

Unlike humans, birds can’t tolerate pollution. A few of them may adapt to certain degrees, but not to extremes.

Thanks to pollution, the house sparrow, which was once abundant in Chennai, has now become rare.

Except for the ubiquitous crow, majority of the indigenous birds have become rare or endangered in Chennai owing to unchecked urbanisation and depleting green cover, admit environmentalists and bird watchers in the city who will be observing the World Sparrow Day on March 20.

“Chennai was once home to sparrows, but today their population has reduced drastically and the same s the case with several other species.

We often blame cell phone towers and radiations as the reason for the disappearance of sparrows, but the problem is that we do not have a concrete study or conclusive report to prove that radiation affects bird life”, said Mr Sudhakar, president, Madras Naturalists Society.

MNS has been observing resident and migratory birds and plans to release a map indicating the sparrow habitats in Chennai, he added.

Professor D. Narasimhan, department of Botany, Madras Christian College, said, “The house sparrow is strongly associated with human habitations, and can live in urban or rural settings, but the city’s housing pattern has become unfriendly for nesting sparrows”.

Also, sparrows are low flying birds and cannot build nests in high-rises and flats, explained the botanist. Once sparrows used to nest above switch boards or in electrical fittings, but today even wirings are sealed leaving the tiny birds without space for nesting, he added.

The house sparrow feeds mostly on seeds of grains and weeds, and insects; it can perform complex and unusual tasks to obtain food. Details into its food availability can also help trace the reason behind their disappearance, said Mr Sudhakar.

http://www.deccanchronicle.com/channels/cities/chennai/trail-house-sparrows-871 

Nitrogen from Humans Pollutes Remote Lakes for More Than a Century

ScienceDaily (Dec. 15, 2011) — 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.


"When it comes to nitrogen associated with humans, most studies have focused on local and regional effects of pollution and have missed the planetary scale changes," Holtgrieve said. "Our study is the first large-scale synthesis to demonstrate that biologically-active nitrogen associated with human society is being transported in the atmosphere to the most remote ecosystems on the planet."

Burning fossil fuel and using agricultural fertilizers are two key ways humans increase the amount of nitrogen entering the atmosphere. Once in the atmosphere, this nitrogen is distributed by atmospheric currents before being deposited back on Earth in rain and snow, often thousands of miles from the source.

"Turns out the world, for nitrogen, is a much smaller place than we'd assumed," said co-author Daniel Schindler, UW professor of aquatic and fishery sciences and the Harriet Bullitt Chair in conservation.


Although nitrogen is a vital nutrient for life -- so much so that farmers apply fertilizers containing it to bolster food crops -- too much nitrogen can be harmful. It has been reported that humans already have doubled the rate of nitrogen released to the biosphere since 1950. Humans now contribute more nitrogen to the biosphere than all natural processes combined. When produced in developed areas, this excess nitrogen can lead to smog, acid rain and water pollution.

The effects on remote forests, lands and lakes are largely unknown, Schindler said. An increasing body of evidence, however, shows that the biological composition of microscopic communities in Arctic lakes changed with the arrival of human-derived nitrogen. This global nitrogen pollution may interact with climate change to produce a "double whammy" that could alter remote lakes in ways not seen in the past 10,000 years, Schindler said

Using statistical models to analyze nitrogen characteristics of lake sediments, the authors show that the chemical fingerprint of nitrogen pollution started about 115 years ago, shortly after the Industrial Revolution, and that the rate of chemical changes increased during the last 60 years with industrial production of nitrogen for fertilizers.

"This study also provides an explicit chronology for entry of the Earth into the 'Anthropocene' -- a new geological era in which global biogeochemical cycles have been fundamentally altered by human activity," said co-author Peter Leavitt, professor of biology at the University of Regina and the Canada Research Chair in environmental change. "The signal will only get stronger in the future as we double fertilizer use in the next 40 years to feed 3 billion more people."

The authors conclude that climate, natural sources of nitrogen, and normal chemical processes on land and in water cannot account for the chemical signals they observe.

"Given the broad geographic distribution of our sites -- and the range of temperate, alpine and arctic ecosystems -- we believe the best explanation is that human-derived nitrogen was deposited from the atmosphere," Holtgrieve said.

"The global change debate is dominated by discussions of carbon emissions, whether among scientists, politicians or the lay public," said co-author Alexander Wolfe, professor of earth and atmospheric sciences at the University of Alberta. "However, in a relative sense, the global nitrogen cycle has been far more perturbed by humanity than that of carbon."

Other co-authors are William Hobbs with Science Museum of Minnesota, Eric Ward with National Marine Fisheries Service, Lynda Bunting with University of Regina, Guangjie Chen with McGill University and Yunnan Normal University, Bruce Finney and Mark Shapley with Idaho State University, Irene Gregory-Eaves with McGill University, Sofia Holmgren with Lund University, Mark Lisac and Patrick Walsh with U.S. Fish and Wildlife Service, Peter Lisi and Lauren Rogers with the University of Washington, Koren Nydick with Mountain Studies Institute, Colorado, Jasmine Saros with University of Maine, and Daniel Selbie with Fisheries and Oceans Canada.

Funding came from the Gordon and Betty Moore Foundation, U.S. Fish and Wildlife Service, Alberta Water Research Institute, Natural Sciences and Engineering Research Council of Canada, the National Science Foundation and Canada Foundation for Innovation.

http://www.sciencedaily.com/releases/2011/12/111215141607.htm

Pollution: Sea Turtle Dies After Swallowing 317 Pieces Of Plastic

Pollution: Sea Turtle Dies After Swallowing 317 Pieces Of Plastic
Leanne Hall, Global Animal

(SEA TURTLES) AUSTRALIA - Plastic bags, small lids and even lollipop sticks were among the 317 pieces of plastic found in the digestive system of a green sea turtle who washed ashore on a New South Whales beach earlier this month. The young turtle was the worst case Rochelle Ferris and her team of volunteers at Australian Seabird Rescue had seen during their 15 years of work in the area.

The team responds to "about 40 sea turtle strandings a year that are directly related to plastic ingestion," according to Ferris. Unfortunately, the turtles mistake the plastic pieces for food.

A shocking 36 percent of sea turtles are affected by marine debris, such as plastic, according to recent research at the University of Queensland. Although the Australian Federal Government has addressed the issue, it is obvious that more needs to be done to reduce the amount of waste entering the ocean and inevitably destroying its inhabitants.

This tragic death demonstrates the negative impact we have on our oceanic friends. Lessen your impact by remembering the three Rs: Reduce, Reuse, Recycle.

For more information and to watch a video in which Ferris discusses the incident as well as the larger issues, goto http://www.abc.net.au/local/videos/2011/06/30/3257970.htm?site=northcoast

Researchers find plastic in more than 9% of fish in northern Pacific Ocean

The first scientific results from an ambitious voyage led by a group of graduate students from Scripps Institution of Oceanography at UC San Diego offer a stark view of human pollution and its infiltration of an area of the ocean that has been labeled as the “Great Pacific Garbage Patch.”

These are two lanternfish and several bits of plastic collected during the SEAPLEX voyage [Credit: J. Leicther]

Two graduate students with the Scripps Environmental Accumulation of Plastic Expedition, or SEAPLEX, found evidence of plastic waste in more than nine percent of the stomachs of fish collected during their voyage to the North Pacific Subtropical Gyre. Based on their evidence, authors Peter Davison and Rebecca Asch estimate that fish in the intermediate ocean depths of the North Pacific ingest plastic at a rate of roughly 12,000- to 24,000 tons per year.


Their results were published June 27 in the journal Marine Ecology Progress Series.

During the SEAPLEX voyage in August 2009, a team of Scripps graduate students traveled more than 1,000 miles west of California to the eastern sector of the North Pacific Subtropical Gyre aboard the Scripps research vessel New Horizon. Over 20 days the students, New Horizon crew and expedition volunteers conducted comprehensive and rigorous scientific sampling at numerous locations. They collected fish specimens, water samples and marine debris at depths ranging from the sea surface to thousands of feet depth

Of the 141 fishes spanning 27 species dissected in the study, Davison and Asch found that 9.2 percent of the stomach contents of mid-water fishes contained plastic debris, primarily broken-down bits smaller than a human fingernail. The researchers say the majority of the stomach plastic pieces were so small their origin could not be determined.

“About nine percent of examined fishes contained plastic in their stomach. That is an underestimate of the true ingestion rate because a fish may regurgitate or pass a plastic item, or even die from eating it. We didn’t measure those rates, so our nine percent figure is too low by an unknown amount,” said Davison.

The authors say previous studies on fish and plastic ingestion may have included so-called “net-feeding” biases. Net feeding can lead to artificially high cases of plastic ingestion by fishes while they are confined in a net with a high concentration of plastic debris. The Scripps study’s results were designed to avoid such bias. The highest concentrations of plastic were retrieved by a surface collecting device called a “manta net,” which sampled for only 15 minutes at a time. The short sampling time minimizes the risk of net feeding by preventing large concentrations of plastic from building up, and also by reducing the amount of time that a captured fish spends in the net. In addition to the manta net, the fishes were also collected with other nets that sample deeper in the water column where there is less plastic to be ingested through net feeding.

The new study focused on the prevalence of plastic ingestion, but effects such as toxicological impacts on fish and composition of the plastic were outside of the study’s goals.

The majority of fish examined in the study were myctophids, commonly called lanternfish because of their luminescent tissue. Lanternfishes are hypothesized to use luminescence for several purposes, including counter-illumination (thwarts predators attempting to silhouette the lanternfish against sunlight), mate attraction and identification and illumination of prey. Such fish generally inhabit the 200- to 1,000-meter (650- to 3,280-foot) depth during the day and swim to the surface at night.

“These fish have an important role in the food chain because they connect plankton at the base of the food chain with higher levels. We have estimated the incidence at which plastic is entering the food chain and I think there are potential impacts, but what those impacts are will take more research,” said Asch.

Rather than a visible “patch” or “island” of trash, marine debris is highly dispersed across thousands of miles of the North Pacific Subtropical Gyre. The debris area cannot be mapped from air or space, so SEAPLEX researchers collected samples in 132 net tows (130 of which contained plastic) across a distance of more than 2,375 kilometers (1,700 miles) in an attempt to find the boundaries of the patch. The region, a “convergence zone” where floating debris in water congregates, is generally avoided by mariners due to its calm winds and mild currents. The North Pacific Subtropical Gyre has been understudied by scientists, leaving many open questions about marine debris in the area and its long-term effects on the marine environment.

“This study clearly emphasizes the importance of directly sampling in the environment where the impacts may be occurring,” said James Leichter, a Scripps associate professor of biological oceanography who participated in the SEAPLEX expedition but was not an author of the new paper. “We are seeing that most of our prior predictions and expectations about potential impacts have been based on speculation rather than evidence and in many cases we have in fact underestimated the magnitude of effects. SEAPLEX also clearly illustrates how relatively small amounts of funding directed for novel field sampling and work in remote places can vastly increase our knowledge and understanding of environmental problems.”

Author: Mario Aguilera
Source: University of California - San Diego
http://archaeologynewsnetwork.blogspot.com/2011/07/researchers-find-plastic-in-more-than-9.html