WITH the first spell of monsoon in mid-June people in Bargarh, Nuapada, Kalahandi and Sambalpur districts in Orissa experienced something they had never seen before: a grayish layer on leaves, vehicles and elsewhere. "I was surprised to see the leaves of trees in my medicinal plant nursery covered with white and grey mud-like substances," said Biswanath Hota, a retired divisional forest officer, who believed it to be acid rain.
Hota quickly sent samples of leaves from his nursery in Bhawanipatna, Kalahadi, to his friend Durga Prasad Nayak, an environmental activist. Nayak took the samples to the Sambalpur University's Department of Environmental Sciences for testing evidence of acid rain. P C Mishra, a professor in the department, did not find any trace of acid rain in them, but he did not rule out the incidence of acid rain.
"What I got was a bunch of leaves that had been collected a few days ago and had changed hands many times. So it was difficult to do a proper scientific analysis," said Mishra. "This being a forested area with no industries, I am surprised that this kind of rain has occurred. One could also say it is fly ash, which has travelled hundreds of kilometres from industrial belts. It's worrying and needs a thorough scientific study."
Mishra warned that increased dust concentration can affect crop productivity. "In my study of the area around MCL coal operations, I found that coal dust had severely affected plant growth and productivity. Dust on the leaf surface retards plant productivity," he said.
Arttabandhu Mishra, a retired professor of the university, suspects the rain was caused by Orissa's thermal power belts of Angul-Talcher and Ib Valley. "Burning coal is the main cause of acid rain and Orissa's two big coal fields emit over 320 tonnes of sulphur dioxide, 919 tonnes of nitrogen oxide and 33,883 tonnes of carbon dioxide. Acid rain can travel up to 400 km, and surely the rain in the region was acid rain," he said.
Sitikanta Sahu, regional manager, Orissa Pollution Control Board, said, "We have asked our Rayagada regional officer to find samples of the first spells of rain for testing the Ph level. Acid rain is a concern but we cannot be sure that it was due to coal fields of Orissa. Industrial units in Maharashtra and Chhattisgarh could also have caused this."
Whatever the cause, farmers are worried about the impact of the unusual substance on crops. Land in western Orissa is already going barren. With a severely depleted forest belt around coal reserves and thermal power plants, the negative impacts of acid rain would be phenomenal, said Arttabandhu Mishra.
Nayak accused the government of failing to respond to weather signals. The Padampur-Nuapada region experienced smog for 25 days in February-March. "Everyone was scared and the media also raised the issue. However, the government and the pollution control board did nothing," said Nayak.

SYDNEY (Reuters) - Rising acidity in the ocean caused by seas absorbing greenhouse carbon dioxide could make low-lying island nations like Kiribati and the Maldives more vulnerable to storms as their coral reefs struggle to survive, say scientists.
Carbon dioxide in the atmosphere is at its highest level in the past 650,000 years, possible 23 million years, and half has now been dissolved into the oceans making them more acidic.
Ocean acidification, which is projected to spread extensively north from the Antarctic by 2100, makes it difficult or impossible for some animals, like coral and starfish, to produce their shells and skeletons.
"If ocean acidification weakens the structure of reef-forming corals and algae, tropical systems (islands) will be more vulnerable to physical impacts from storms and cyclones," said a new report by some of the world's leading marine scientists.
"By 2100, it is expected that some reefs will become marginal and reef calcification will decline," said the report, by the Antarctic Climate & Ecosystems Cooperative Research Centre, released on Monday.
The report cited Kiribati in the South Pacific and the Maldives in the Indian Ocean as being more vulnerable to tropical storms if ocean acidification continues to rise.
"These impacts will also directly affect important commercial, recreational or subsistence reef fisheries where the target species depend on reef habitats," said the report, released at an ocean acidification conference in Hobart.
Ocean acidification is when carbon dioxide dissolves in the sea forming a weak acid, carbonic acid. Human-induced carbon dioxide has largely been produced by burning fossil fuels, agricultural practices and concrete production.
"The ocean is a major sink for CO2 emissions and has absorbed about 48 percent of the CO2 emitted by human activities since preindustrial times," said the report.
FOOD CHAIN THREATENED
Ocean acidification is already affecting the cold water marine life of the Southern Ocean where most carbon dioxide has dissolved and U.S. researchers said it was now appearing on the Pacific North American continental shelf.
"The Southern Ocean is a biogeochemical 'harbinger' for the impacts of acidification that will spread throughout the global ocean," said the report.
By 2060, Antarctic polar waters would experience carbonate ion concentrations so low that one form of calcium carbonate, aragonite, will not be available for organisms to build shells.
Ocean acidification may also interfere with the respiration of fish, the larval development of marine organisms and the ability of oceans to absorb nutrients and toxins.
"Ocean acidification is likely to have an ecological cascade effect right up to parts of the food web that are important to human beings, such as fish and shell fish," said research scientist Will Howard from the Antarctic research centre.
The report said ice cores showed that the current rate of increase of carbon dioxide in the atmosphere is 100 times greater than the most rapid increases experienced in the last 650,000 years. Sedimentary records suggest carbon dioxide levels were higher than at anytime in the last 23 million years.
It said atmospheric carbon dioxide levels are expected to reach about double pre-industrial levels within this century, resulting in an acidification of oceans three times the level experienced during the last major rise in carbon dioxide during the last glacial period 15,000 years ago.
"Many (marine) species have taken millennia to evolve and it is unknown whether they can (or will) be able to adapt to the relatively rapid rate of ocean acidification, in the order of decades not millennia," said the report.

Emissions of carbon dioxide (CO2) through human activities have a well known impact on the Earth's climate. What is not so well known is that the absorption of this CO2 by the oceans is causing inexorable acidification of sea water. But what impact is this phenomenon having on marine organisms and ecosystems? This is a question to which researchers have few answers as yet.
That is why the European Union has recently given its support to EPOCA, the European Project on Ocean Acidification, which will be launched in Nice (France) on 10 June 2008.
EPOCA's goal is to document ocean acidification, investigate its impact on biological processes, predict its consequences over the next 100 years, and advise policy-makers on potential thresholds or tipping points that should not be exceeded. The project is coordinated by Jean-Pierre Gattuso, a CNRS researcher at the Oceanography Laboratory at Villefranche-sur-mer (LOV(1)), and brings together a consortium of 27 partners, including CNRS and the French Atomic Energy Agency (CEA), from 9 countries. Many of the leading oceanographic institutions across Europe and more than 100 permanent scientists are involved. The budget is €16.5 million over 4 years, including €6.5 million from the European Commission.
Over 71% of the Earth's surface is covered by the oceans, which are home to an incredibly diverse flora and fauna. They play a key role in regulating the climate and levels of carbon dioxide (CO2), one of the main greenhouse gases. Over the last 200 years (since the beginning of the industrial revolution), the oceans have absorbed about one third of the carbon dioxide produced by human activities, a total of 120 billion tons. Without this absorption, the amount of CO2present in the atmosphere and its effects on the climate would undoubtedly be far greater.
In fact, over 25 million tons of CO2 dissolve in seawater every day. However, the oceans do not escape unscathed. When CO2 dissolves in sea water, it causes the formation of carbonic acid, which leads to a fall in pH (the pH scale is used to measure acidity(2)). This change is called "ocean acidification"� and is happening at a rate that has not been experienced probably for the last 20 million years.
The effects of this huge input of CO2 into the oceans only began to be studied in the late 1990s(3) and are still poorly understood. One of the most likely consequences will be slower growth of organisms with calcareous skeletons, such as corals, mollusks, algae, etc. Obtaining more information about ocean acidification is a major environmental priority because of the threat it poses to certain species and ecosystems.
EPOCA should help us to understand the effects of the acidification of sea water as well as its impact on marine organisms and ecosystems. More specifically, the project has four goals:
1. Document the changes in ocean chemistry and biogeography across space and time. Paleo-reconstruction methods will be used on several natural/biological archives, including foraminifera and deep-sea corals, to determine past variability in ocean chemistry and to tie these to present-day chemical and biological observations.
2. Determine the sensitivity of marine organisms, communities and ecosystems to ocean acidification. Molecular to biochemical, physiological and ecological approaches will be combined with laboratory and field-based perturbation experiments to quantify biological responses to ocean acidification, assess the potential for adaptation, and determine the consequences for biogeochemical cycling. Laboratory experiments will focus on key organisms selected on the basis of their ecological, biogeochemical or socio-economic importance. Field studies will be carried out in systems (areas/regions) deemed most sensitive to ocean acidification.
3. Integrate results on the impact of ocean acidification on marine ecosystems in biogeochemical, sediment, and coupled ocean-climate models to better understand and predict the responses of the Earth system to ocean acidification. Special attention will be paid to the potential feedbacks of the physiological changes in the carbon, nitrogen, sulfur and iron cycles.
4. Assess uncertainties, risks and thresholds ("tipping points") related to ocean acidification at scales ranging from sub-cellular to ecosystem and local to global. It will also assess the decrease in CO2 emissions required to avoid these thresholds and describe the change and the subsequent risk to the marine environment and Earth system, should these emissions be exceeded.

THERE is growing evidence to believe that the incidence of acid rain is increasing in India. Many experts link the phenomenon with increasing industrialisation in the country.
On August 23, Union minister of state for environment and forest, Namo Narain Meena, informed the Rajya Sabha that the India Meteorological Department (IMD) has found increasing acidity in rain samples from Pune and Nagpur. The samples were acidic with pH values less than 5--pH is a measure of the acidity or alkalinity of a solution.
IMD maintains a network of Global Atmospheric Watch stations that follow World Meteorological Organization norms. It has been analysing rainwater samples from 10 locations for almost three decades. The monitoring areas are Pune, Nagpur, Allahabad, Jodhpur, Kodaikanal, Minicoy, Mohanbari, Port Blair, Srinagar and Vishakhapatnam.
A 2004 paper in the journal Environment Science and Engineering by IMD scientists says pH values in rainwater has been dropping in India. The study finds a link between acid rains and the rising levels of sulphur and nitrogen compounds in the atmosphere. "The data is extensive and irrefutable," says Jayanta Sarkar, lead author and former director of air pollution unit, IMDin Pune. All stations except Kodaikanal have shown a two-fold rise in sulphate concentration in the rain (see graph Bad indicators). The scientists cite the example of northeast India where oil refineries, fertiliser factories, thermal power plant and oil and gas installations release sulphate and nitrate compounds into the atmosphere, raising acid content in the rain.
There are other reasons too. In most parts of India, the alkaline dust in the atmosphere neutralises the acid content in rain. But "rainwater at Mohanbari in Assam, is more acidic in nature because the area lacks neutralising agents", says Vijay Kumar Soni of IMD.

How and why ?
Industrialisation is the prime driver of the acid rain phenomenon. Besides acid rain, experts also link changes in precipitation patterns to rapid industrialisation and urbanisation across the globe. The changes include increased rains and snowfall in northern regions, and drier conditions in tropical areas.
A recent paper in Nature (Vol 448, No 7157) clearly establishes this link. Human-induced climate change in the past century has contributed to the drying observed in Mexico, Central America and northern Africa, says Canadian climate scientist Xuebin Zhang who is one of the authors. The paper says that these shifts may have had significant effects on ecosystems especially in regions that are sensitive to changes in precipitation, such as the Sahel region in northern Africa.
Acid rain has many baneful effects. It upsets chemical balance in water bodies, releasing toxic metals. This causes serious health problems to people. Acid rain also triggers leaching of important nutrients from the soil, affecting plants. When snow with acid deposit melts, higher concentration of acid gets released, affecting fish. Acid rains also cause corrosion in buildings--the Taj Mahal being a case in point.
U Kulshrestha of Indian Institute of Chemical Technology, Hyderabad points to another concern acid rain over oceans. In winter, when the wind blows from land to the oceans in South Asia, it carries effluents from India, China, Japan. The alkaline dust suspension is heavy and not carried that far. So, the rains in the Indian Ocean and the Arabian Sea and the Bay of Bengal have become acidic.
Studies show the importance to regularly monitor more places for acid rains. But the mechanism to study acid rains is at present inadequate in India. IMD stations are not located in the most polluted areas in the country. The department has not yet looked into all the industrial areas. "We do not have data from these areas. The condition there will be much worse," says Sarkar.

Research Suggests Sulfur, Nitrogen Emissions Play a Role in Changing Chemistry Near the CoastResearch suggests sulfur, nitrogen emissions play a role in changing chemistry near the coast.
The release of sulfur and nitrogen into the atmosphere by power plants and agricultural activities plays a minor role in making the ocean more acidic on a global scale, but the impact is greatly amplified in the shallower waters of the coastal ocean, according to new research by atmospheric and marine chemists.
Ocean "acidification" occurs when chemical compounds such as carbon dioxide, sulfur, or nitrogen mix with seawater, a process which lowers the pH and reduces the storage of carbon. Ocean acidification hampers the ability of marine organisms—such as sea urchins, corals, and certain types of plankton—to harness calcium carbonate for making hard outer shells or "exoskeletons." These organisms provide essential food and habitat to other species, so their demise could affect entire ocean ecosystems.
The findings were published this week in the online "early edition" of the Proceedings of the National Academy of Sciences; a printed version will be issued later this month.
"Acid rain isn't just a problem of the land; it's also affecting the ocean," said Scott Doney, lead author of the study and a senior scientist in the Department of Marine Chemistry and Geochemistry at the Woods Hole Oceanographic Institution (WHOI). "That effect is most pronounced near the coasts, which are already some of the most heavily affected and vulnerable parts of the ocean due to pollution, over-fishing, and climate change."
In addition to acidification, excess nitrogen inputs from the atmosphere promote increased growth of phytoplankton and other marine plants which, in turn, may cause more frequent harmful algal blooms and eutrophication (the creation of oxygen-depleted "dead zones") in some parts of the ocean.
Doney collaborated on the project with Natalie Mahowald, Jean-Francois Lamarque, and Phil Rasch of the National Center for Atmospheric Research, Richard Feely of the Pacific Marine Environmental Laboratory, Fred Mackenzie of the University of Hawaii, and Ivan Lima of the WHOI Marine Chemistry and Geochemistry Department.
"Most studies have traditionally focused only on fossil fuel emissions and the role of carbon dioxide in ocean acidification, which is certainly the dominant issue," Doney said. "But no one has really addressed the role of acid rain and nitrogen."
The research team compiled and analyzed many publicly available data sets on fossil fuel emissions, agricultural, and other atmospheric emissions. They built theoretical and computational models of the ocean and atmosphere to simulate where the nitrogen and sulfur em9/7/2007issions were likely to have the most impact. They also compared their model results with field observations made by other scientists in the coastal waters around the United States.
Farming, livestock husbandry, and the combustion of fossil fuels cause excess sulfur dioxide, ammonia, and nitrogen oxides to be released to the atmosphere, where they are transformed into nitric acid and sulfuric acid. Though much of that acid is deposited on land (since it does not remain in the air for long), some of it can be carried in the air all the way to the coastal ocean.
When nitrogen and sulfur compounds from the atmosphere are mixed into coastal waters, the researchers found, the change in water chemistry was as much as 10 to 50 percent of the total changes caused by acidification from carbon dioxide.
This rain of chemicals changes the chemistry of seawater, with the increase in acidic compounds lowering the pH of the water while reducing the capacity of the upper ocean to store carbon. The most heavily affected areas tend to be downwind of power plants (particularly coal-fired plants) and predominantly on the eastern edges of North America, Europe, and south and east of Asia.
Seawater is slightly basic (pH usually between 7.5 and 8.4), but the ocean surface is already 0.1 pH units lower than it was before the Industrial Revolution. Previous research by Doney and others has suggested that the ocean will become another 0.3 to 0.4 pH units lower by the end of the century, which translates to a 100 to 150 percent increase in acidity.