Rapid Coral Death by a Deadly Chain Reaction

May 23, 2012

Most people are fascinated by the colorful and exotic coral reefs, which form habitats with probably the largest biodiversity. But human civilization is the top danger to these fragile ecosystems through climate change, oxygen depletion and ocean acidification. Industrialization, deforestation and intensive farming in coastal areas are changing dramatically the conditions for life in the oceans. Now scientists at the Max Planck Institute for Marine Microbiology from Bremen together with their colleagues from Australia, Sultanate of Oman and Italy have investigated how and why the corals die when exposed to sedimentation. According to their findings, oxygen depletion, together with an acidification of the environment, creates a chain reaction that leads to coral death.

Since the 1980s the process of coral bleaching is under study: elevated temperatures of 1 to 3 degrees induce the algae to produce toxins. The polyps react by expelling the algae and the coral reef loses its color as if it was bleached. Without its symbionts the coral can survive only several weeks.

In coastal areas with excessive soil erosion where rivers flush nutrients, organics and sediments to the sea, corals can die quickly when exposed to sedimentation. Miriam Weber, scientist at the Max Planck Institute for Marine Microbiology in Bremen, explains the scientific approach." Our idea was that a combination of enhanced deposition of sediments with elevated organic matter load and naturally occurring microorganisms can cause the sudden coral death."

The team of researchers found out the crucial steps:

Phase 1: When a two millimeter layer of sediment enriched with organic compounds covers the corals, the algae will stop photosynthesis, as the light is blocked.

Phase 2: If the sediments are organically enriched, then digestion of the organic material by microbial activity reduces oxygen concentrations underneath the sediment film to zero. Other microbes take over digesting larger carbon compounds via fermentation and hydrolysis thereby lowering the pH.

Phase 3: Lack of oxygen and acidic conditions harm small areas of coral tissue irreversibly. The dead material is digested by microbes producing hydrogen sulfide, a compound that is highly toxic for the remaining corals. The process gains momentum and the remainder of the sediment-covered coral surface is killed in less than 24 hours.

Miriam Weber: "First we thought that the toxic hydrogen sulfide is the first killer, but after intensive studies in the lab and mathematical modeling we could demonstrate that the organic enrichment is the proximal cause, as it leads to lack of oxygen and acidification, kicking the corals out of their natural balance. Hydrogen sulfide just speeds up the spreading of the damage. We were amazed that a mere 1% organic matter in the sediments is enough to trigger this process. The extreme effect of the combination of oxygen depletion and acidification are of importance, keeping in mind the increasing acidification of the oceans. If we want to stop this destruction we need some political sanctions to protect coral reefs."

PepsiCo Seeks to Surpass Coke in Water Conservation in UK

October, 2010

            International drink and snack giant PepsiCo has vowed to cut the carbon emissions and water consumption of its UK operations by 50 percent in five years. PepsiCo, which is the parent company of Britain’s biggest-selling brand of potato chips, says it will switch to potatoes that require less water and are grown using more efficient methods of irrigation. Through these improvements, company officials say they will cut the amount of water required to grow one ton of potatoes from 10 tons to five tons by 2015.

            The company also says it will convert to a lower-carbon type of fertilizer for its 350 UK farms. According to a report in the Guardian, the initiative would surpass similar commitments made by rival Coca-Cola. Both companies have received criticism for depleting water supplies, particularly in drought-prone regions. In India, where advocacy groups are urging more corporate accountability for water consumption, the state of Kerala has banned the sale of Coke, Pepsi, and other soft drinks.

Market for Desalination Plants Expected to Grow by $87 Billion by 2016

January 17 ,2011

            More than $88 billion will be invested in desalination technologies worldwide from 2010 to 2016 as regions face dwindling supplies of freshwater and steep population growth, according to a new report. Declining costs associated with several key desalination technologies - including reverse osmosis - will make saltwater-to-freshwater treatment a more affordable option, according to the report by Pike Research.

            “Desalination is becoming more affordable; thus, an increased number of people can benefit from an almost unlimited resource — seawater,” the report says. The global installed capacity is expected to grow by about 55 million cubic meters per day during that period, representing a 9-percent annual growth rate. About 54 percent of that growth will occur in the Middle East and North Africa.

Canada closing its marine pollution program

May 26, 2012

Canada has been sending letters to government scientists notifying them that their jobs will be eliminated or affected by the closure of the country's marine pollution program - but at least one isn't going without making some noise.

"It's perplexing that we face the loss of this program, given the 25,000 chemicals on the market and the ever-increasing threats posed by shipping and oil and gas exploration and development in temperate and Arctic waters," Peter Ross told msnbc.com. Ross is perhaps Canada's best known marine scientist for his work on identifying killer whales as the most contaminated marine mammals on the planet

The program, which employs 75 staff, is set to be shut down by April 1, 2013, the Victoria Times Colonist reported.

"I cannot think of another industrialized nation that has completely excised marine pollution from its radar," Ross said.

The program is under the Department of Fisheries, which is shedding a total of 400 jobs. More than 600 others will be "affected." Of the some 1,000 jobs impacted, three quarters are with the Canadian Coast Guard.

A Department of Fisheries spokesperson told the Colonist that the cuts would produce $79 million in savings and that an advisory group from academia and the private sector would instead provide advice.

Ross also published an opinion piece, titled "Silent Summer," on environmentalhealthnews.org. He concludes:

"It is with apprehension that I ponder a Canada without any research or monitoring capacity for pollution in our three oceans, or any ability to manage its impacts on commercial fish stocks, traditional foods for over 300,000 aboriginal people and marine wildlife.

"Canada's silence on these issues will be deafening this summer and beyond."

High Concentrations of Toxic Mercury in the Arctic from Circumpolar Rivers

May 22, 2012

Environmental scientists have known that high levels of the toxic element, mercury, have been accumulating in the Arctic Ocean for some time. It was believed to be mostly caused by atmospheric sources stemming from the combustion of coal. However, a new study from the Harvard School of Engineering and Applied Sciences and the Harvard School of Public Health has found that the great majority of Arctic mercury arrives via circumpolar rivers. Some of the largest rivers in the world flow north into the Arctic in Eurasia and North America.

The implications of this finding are significant for predicting future levels of the toxic heavy metal. The levels in the Artic will likely be increasing from the thawing of Arctic soils, releasing mercury into the hydrological cycle.

"The Arctic is a unique environment because it's so remote from most anthropogenic (human-caused) sources of mercury, yet we know that the concentrations of mercury in Arctic marine mammals are among the highest in the world," says lead author Jenny A. Fisher, a postdoctoral fellow at Harvard. "This is dangerous to both marine life and humans."

Mercury is a naturally occurring element that has been enriched in the environment by human activities. It is considered a persistent bioaccumulative toxin because it does not break down in the environment. It travels through the food chain from the lowly plankton all the way up to humans. As it travels up, it becomes more concentrated and lethal. The greatest concern is for the indigenous people of the Arctic who consume large amounts of locally-caught fish and marine mammals.

Through combustion, mercury is emitted into the atmosphere. Once chemical processes make it soluble, it falls back to Earth as rain or show. Some fall directly into the Arctic Ocean, but most fall on the large watersheds of the far north.

The Harvard researchers found that rivers contributed more than double the mercury than the atmosphere by noticing a spike in mercury concentrations during the summer. This could only be explained by the increased river flow from circumpolar melting.

"At this point we can only speculate as to how the mercury enters the river systems, but it appears that climate change may play a large role," says co-author, Daniel Jacob. "As global temperatures rise, we begin to see areas of permafrost thawing and releasing mercury that was locked in the soil; we also see the hydrological cycle changing, increasing the amount of runoff from precipitation that enters the rivers. Another contributing factor could be runoff from gold, silver, and mercury mines in Siberia, which may be polluting the water nearby. We know next to nothing about these pollution sources."

Sewage-Derived Nitrogen Increasingly Polluting Caribbean Ecosystems

May 17, 2011

Nitrogen pollution in our coastal ecosystems, the result of widespread use of synthetic agricultural fertilizers and of human sewage, leads to decreased water transparency, the loss of desirable fish species, and the emergence of toxic phytoplankton species -- such as the algae behind the infamous "red tides" that kill fish. The effects are particularly pronounced in the Gulf of Mexico and the Caribbean.

A study published in the journal Global Change Biology finds that while fertilizer has been the dominant source of nitrogen pollution in Caribbean coastal ecosystems for the past 50 years, such pollution is on the decline, thanks in part to the introduction of more advanced, environmentally responsible agricultural practices during the last decade. But now, sewage-derived nitrogen is increasingly becoming the top source of such pollution in those areas.

"We can't simply say our coastal ecosystem is being polluted by nitrogen," said Kiho Kim, one of the study's authors and chair of environmental science at American University. "The consequences may be the same, but differentiating the source of the pollutants is critical to crafting sustainable solutions -- you can't fix a problem if you don't know what's causing it."

Through a chemical analysis of 300 coral samples from the Smithsonian Institution's National Museum of Natural History's Invertebrate Zoology Collection, Kim and some American University graduate students reconstructed a record of nitrogen inputs into the Caribbean over the last 150 years. Agricultural and sewage pollution create different signatures in organisms like coral.

"We determined that poor stormwater management and wastewater treatment were really to blame over the last decade for nitrogen pollution in the Caribbean," said Kim. "Our next step is to document this process in action."

To do this, Kim will focus on coral samples from the coastal areas of Guam, a small Pacific island that during the next four years will experience a population increase of 20 percent as the U.S. military relocates Marines from Okinawa, Japan to Guam. Guam already has poor waste water infrastructure, and the influx of military personnel will further strain the island's resources. For Kim, the transition presents a unique opportunity to observe and document, in real time, the impact of increased sewage-derived nitrogen on the health of the coral reefs. He has already collected some baseline data in Guam, thanks to a small grant from the National Oceanic and Atmospheric Administration.

Groundwater Pumping Threatens U.S. Food Supply

May 28, 2012

Groundwater depletion has for years been a growing problem in the West, Southwest and elsewhere. Now researchers say it may threaten food supplies in the United States.

The problem is well documented. A study earlier this month found that excess pumping of groundwater is causing seas to rise. (And in March, a study found that 4 million Americans are threatened by rising seas.) Between around 1970 and 1990, sea level rise caused by groundwater pumping was cancelled out by the construction of dams, which trap water in reservoirs so the water so less water goes to the sea, some of the recent research shows. A study in 2008 confirmed this effect. Groundwater pumped for irrigation, drinking water and industrial uses does not typically end up back underground. Instead, it flows into streams or rivers or evaporates into the atmosphere, eventually finding its way to the ocean.

The study, detailed today in the journal Proceedings of the National Academy of Sciences, paints the highest resolution picture yet of how groundwater depletion varies across space and time in California's Central Valley and the High Plains of the central U.S. Researchers hope this information will enable more sustainable use of water in these areas, although they think irrigated agriculture may be unsustainable in some parts.

Three results of the new study are particularly striking: First, during the most recent drought in California's Central Valley, from 2006 to 2009, farmers in the south depleted enough groundwater to fill the nation's largest man-made reservoir, Lake Mead near Las Vegas—a level of groundwater depletion that is unsustainable at current recharge rates. Second, a third of the groundwater depletion in the High Plains occurs in just 4% of the land area. And third, the researchers project that if current trends continue some parts of the southern High Plains that currently support irrigated agriculture, mostly in the Texas Panhandle and western Kansas, will be unable to do so within a few decades.

California's Central Valley is sometimes called the nation's "fruit and vegetable basket." The High Plains, which run from northwest Texas to southern Wyoming and South Dakota, are sometimes called the country's "grain basket." Combined, these two regions produced agricultural products worth $56 billion in 2007, accounting for much of the nation's food production. They also account for half of all groundwater depletion in the U.S., mainly as a result of irrigating crops.

In the early 20th century, farmers in California's Central Valley began pumping groundwater to irrigate their crops. Over time, groundwater levels dropped as much as 400 feet in some places. From the 1930s to '70s, state and federal agencies built a system of dams, reservoirs and canals to transfer water from the relatively water-rich north to the very dry south. Since then, groundwater levels in some areas have risen as much as 300 feet. In the High Plains, farmers first began large-scale pumping of groundwater for crop irrigation in the 1930s and '40s; but irrigation greatly expanded in response to the 1950s drought. Since then, groundwater levels there have steadily declined, in some places more than 150 feet.

Scanlon and her colleagues suggested several ways to make irrigated agriculture in the Central Valley more sustainable: Replace flood irrigation systems (used on about half of crops) with more efficient sprinkle and drip systems and expand the practice of groundwater banking - storing excess surface water in times of plenty in the same natural aquifers that supply groundwater for irrigation. Groundwater banks currently store 2 to 3 cubic kilometers of water in California, similar to or greater than storage capacities of many of the large surface water reservoirs in the state. Groundwater banks provide a valuable approach for evening out water supplies during climate extremes ranging from droughts to floods.

For various reasons, Scanlon and other experts don't think these or other engineering approaches will solve the problem in the High Plains. When groundwater levels drop too low to support irrigated farming in some areas, farmers there will be forced to switch from irrigated crops such as corn to non-irrigated crops such as sorghum, or to rangeland. The transition could be economically challenging because non-irrigated crops generate about half the yield of irrigated crops and are far more vulnerable to droughts.

"Basically irrigated agriculture in much of the southern High Plains is unsustainable," Scanlon said.