The Global Fool

our planet is our village

Global Threats: Water Scarcity and Uncertainty in the Estimates of Groundwater Availability
Jun28

Global Threats: Water Scarcity and Uncertainty in the Estimates of Groundwater Availability

By Roberta Attanasio Groundwater is any water that lies in aquifers beneath the land surface. While some of the water that falls as precipitation is channeled into streams or lakes, and some is used by plants or evaporates back into the atmosphere, most of it seeps underground in the cracks and spaces present in soil, sand and rock. Underground layers of rock that are saturated with groundwater are called aquifers. The groundwater contained in aquifers is one of the most important sources of water on our planet, and can be brought to the surface through natural springs or by pumping. Groundwater is constantly replenished (recharged), as part of the natural water cycle, by rain and melting snow, and to a smaller extent by surface water (rivers and lakes). Groundwater recharge is an important process for sustainable groundwater management — the volume of water extracted from an aquifer should be less than or equal to the volume of water that is recharged. Artificial recharge — the practice of increasing by artificial means the amount of water that enters an aquifer — is now gaining increasing acceptance for the support of sustainable groundwater management. Groundwater is among the most important natural resources in the United States. It provides half our drinking water and is essential to the vitality of agriculture and industry, as well as to the health of rivers, wetlands, and estuaries throughout the country. However, the future availability of groundwater to meet domestic, agricultural, industrial, and environmental needs is uncertain. Large-scale development of groundwater resources is leading to declines in groundwater levels not only in the United States, but also at a global level. In many arid and semi-arid regions in which water scarcity is almost endemic, groundwater plays a major role in meeting domestic and irrigation demands. Unfortunately, it is massively used for irrigation without adequate planning, raising serious concerns on the sustainability of such an intensive use of groundwater resources. Now, results from two new studies published in the journal Water Resources Research show that, while civilization is rapidly draining some of its largest groundwater basins, there is little to no accurate data about how much water remains in them. The researchers conclude that significant segments of Earth’s population are consuming groundwater quickly without knowing when it might run out. The studies characterized groundwater losses via data from space, using readings generated by NASA’s twin GRACE satellites through measurements of dips and bumps in Earth’s gravity, which is affected by the weight of water. In one of the studies (Quantifying renewable groundwater stress with GRACE), researchers examined — between 2003 and 2013 — the planet’s 37 largest aquifers. The eight...

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Quality Water, Quality Life: Aquatic Health and Contaminants in the Midcoast Oregon Salmon Watersheds
Jun08

Quality Water, Quality Life: Aquatic Health and Contaminants in the Midcoast Oregon Salmon Watersheds

A guest post by Ray Kinney From ridge tops to reefs, environmental degradation has caused many salmon populations to decline to one to ten percent of former numbers. Young salmon survival in freshwater is only 2 to 5% from egg to smolt phase just before entering the ocean phase of their life cycle. Many causative effects for this decline are known, but many remain to be clarified. Politics often prevents adequate investigation of contaminant effects for water quality. Chronic low dose accumulative effects of toxic contaminants take a toll that is generally unrecognized by fisheries managers. Our benevolent rainfall flows down out of the Coast Range to become, once again, part of the sea and the productivity of the salmon cycle of the near-shore ocean. Nutrients from the ocean, in the form of salmon and lamprey spawner carcasses, had fertilized our forests, streams, and rivers like an incoming tide for thousands of years. Our forest garden grew rich because of this tide of nutrients. Reduced numbers means reduced nutrients, which reduces development, growth, and survival abilities of the fish. The land also nourishes the sea. Freshwater flows down out of the mountains, past our farms and towns, through the jetties, and out over the continental shelf. These nutrient tides over land and sea have been shaping salmon for thousands of years, providing diversity, fitness, and resilience to the young fish and other stream organisms that support the salmon cycle complexity. For many hundreds of years humans have increasingly affected the quality of this complexity in ways that have stressed the fish. In the last two hundred years we have greatly increased pollution. Fish harvest levels increased unsustainably, while beaver and timber harvests altered the landscape stressing the salmon cycle. Increasing pollutants have contaminated the flow to the sea. Copious leaching rainfall and snowmelt dissolve and transport nutrients and contaminants down the river out of the Coast Range. Calcium and iron ride the waters downstream and out over the shelf during the winter, enriching the sea floor mud. As upwelling conditions increase in the summer, much of this iron distributes northward with the currents and combines with nitrates to fertilize plankton blooms that feed the food chain for the salmon. Iron and nitrate are in shorter supply over much of the ocean and limit productivity in many parts of the ocean. Here, off of the Oregon coast, the iron leached from our soils provides an important key to salmon ocean productivity. Large quantities of nitrate ride downstream through the freshwater, from red alder tree vegetation cover concentrations in our timberland. The red alder ‘fix’ nitrogen out of the air providing fertilizer...

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Neonicotinoid Pesticides: Bad for Bees, Bad for Many Other Species
May06

Neonicotinoid Pesticides: Bad for Bees, Bad for Many Other Species

By Roberta Attanasio Do neonicotinoid pesticides harm bees? According to scientific evidence, the answer is “yes”. Indeed, scientific evidence for the toxic effects of neonicotinoid pesticides on bees is accumulating at an increasing pace. And, on the basis of scientific evidence, the European Commission banned in 2013 the use of three neonicotinoids — clothianidin, imidacloprid and thiamethoxam — on flowering plants. The ban was motivated by findings from the European Food Safety Authority (EFSA); these findings were based on the evaluation of the scientific studies available at the time. Now, a report from the European Academies Science Advisory Council (EASAC) emphasizes that bees are not the only species affected by the use of these pesticides. The report is based on the findings of an international group of independent scientists with expertise ranging from pollination biology through systems ecology to toxicology. According to the report, there is more and more scientific evidence that widespread use of neonicotinoids has severe effects on species that are important for pollination, natural pest control, and soil productivity. For example, predatory insects such as parasitic wasps and ladybugs that aid in pest control, and earthworms that improve soil productivity, are all harmed. In addition, neonicotinoid use has a negative impact on biodiversity. Neonicotinoids are neurotoxic (poisonous to nerves or nervous tissue of insects and other organisms), and act systemically in the plants — their solubility in water allows them to be absorbed and spread via the plant’s vascular system to all of its tissues. They reach leaves, flowers, roots and stems, even pollen and nectar, and become toxic not only to sap-sucking pests such as aphids or mealybugs, but also to any other species that harvest the different parts of the plant. In addition, exposure is possible across trophic levels, as for example in the case of bees foraging on honey dew, predators exposed through ingesting prey, or soil organisms decomposing contaminated organic matter. There is also evidence for sub-lethal effects of very low levels of neonicotinoids, over extended periods of time, on non-target beneficial organisms. Repeated sub-lethal doses may eventually become deadly once a certain threshold is passed. The EASAC report acknowledges that use of all pesticides is based on the balance between the desired effect on food production and the inevitable risk of collateral damage to non-target species and the environment. However, for neonicotinoids, scientific evidence accumulated over the last two years suggests that, rather than balance, there in imbalance —  the risk of collateral damage is too high when compared to the benefits. Peter Neumann, EASAC’s Chair of the Working Group, wrote in an article published in the journal Nature that the...

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Global Threats: Contamination of Surface Waters by Agricultural Insecticides
Apr26

Global Threats: Contamination of Surface Waters by Agricultural Insecticides

By Roberta Attanasio The use of agricultural insecticides — toxic substances developed to target and kill insects that damage crops — has sparked controversy since the dawn of the “chemical age”, which started in the 1950s. The benefits of agricultural insecticides — for example, increased food production — are undeniable. Unfortunately, along with benefits, there are considerable unwanted effects. Ideally, insecticides must be lethal to the target insects, but not to non-target species. However, these toxic substances do not target only insects — they target many more organisms, including man. Thus, the toxic brew of agricultural insecticides threatens the ecological integrity of aquatic and terrestrial ecosystems. Indeed, agricultural systems play a significant role in global environmental degradation — among other harmful effects, they drive the loss of aquatic biodiversity. In 2013, a team of researchers from German and Australian institutions showed that the loss of aquatic biodiversity in regions of Germany, France, and Australia, is primarily due to the disappearance of several groups of species — stoneflies, mayflies, caddisflies, and dragonflies — which are especially susceptible to insecticides. These insects are important members of the food chain right up to fish and birds. Despite these worrisome results, the degree of insecticide contamination worldwide was unknown until two weeks ago, when results from a new study (Agricultural insecticides threaten surface waters at the global scale) showed that surface water pollution resulting from the current use of agricultural insecticides constitutes an excessive threat to aquatic biodiversity. For the new study, researchers at the Institute for Environmental Science of the University of Koblenz-Landau evaluated, for the first time, comprehensive global insecticide contamination data for agricultural surface waters. They examined 838 studies conducted between 1962 and 2012 and covering 2,500 aquatic sites in 73 countries, using the legally-accepted regulatory threshold levels (RTLs) as defined during the official pesticide authorization procedures. The researchers found that insecticide contamination occurs rarely in the aquatic environment — only an estimated 2.6% of the samples contained measurable levels of insecticides. However, for the sites containing insecticides, the results were alarming — more than 40% of the water-phase samples, and more than 80% of sediment samples in which insecticides were detected, yielded concentrations that exceeded the respective RTLs. They concluded that insecticides pose substantial threats to the biodiversity of global agricultural surface waters and that the current regulatory risk assessment schemes and pesticide authorization procedures fail to protect the aquatic environment. Ralf Schulz, one of the researchers, said in a press release: “Potential reasons for these findings are failures of current risk assessment procedures, or the non-adherence of farmers to pesticide application prescriptions.” It is likely that the global picture emerging from the...

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Small Predator Diversity Plays a Significant Role in the Spread of Infectious Diseases
Mar23

Small Predator Diversity Plays a Significant Role in the Spread of Infectious Diseases

By Roberta Attanasio Biodiversity is a term coined to describe the diversity of all living things, from human beings to microorganisms. A New York Times editorial published almost two decades ago aptly describes the importance of the biodiversity concept: “Biodiversity is a hugely important concept that stresses the coherence and interdependence of all forms of life on earth and a new willingness to appraise the meaning of that interdependence, not just for humans but for every one of life’s component parts.” The editorial goes on to illustrate the alarming effects of biodiversity loss: “Biodiversity is a way of talking about what scientists have long understood and a way of reminding the rest of us of a cardinal fact: that we are standing in the midst of the earth’s sixth great extinction of diverse species, that this extinction is driven by us and that we are not now and will never be immune to its effects.” One of these effects is the worldwide spike in infectious diseases, as suggested by a study recently published in the journal Proceedings of the National Academy of Sciences. The study (Predator diversity, intraguild predation, and indirect effects drive parasite transmission) explores how the diversity of small predators shapes the transmission of parasites in wetlands. Lead author Jason Rohr said in a press release by Penn State: “In the last century, there has been an unprecedented global increase in infectious diseases and a concomitant decline in and homogenization of biodiversity. The controversial ‘dilution effect hypothesis’ suggests that the two phenomena might be linked, or that biodiversity often decreases disease risk.” The study, which included a series of laboratory experiments, field surveys and mathematical modeling, shows that — in presence of various species of dragonfly larvae — there is a reduction of frog infections caused by trematodes, which are parasitic flatworms also known as flukes. The dragonfly larvae are small predators that eat trematodes. Val Beasley, senior author of the study, said in the press release that various species of trematodes penetrate tadpoles. The trematodes sometimes kill the tadpoles. In other instances, the trematodes weaken them by causing tissue damage, kidney failure, or severe limb deformities while the tadpoles develop into frogs. He added that other vertebrate species commonly catch trematode infections from bodies of water. These vertebrate species include wildlife, domestic animals and humans — mostly children — who are commonly affected by schistosomiasis in tropical parts of the world. Schistosomiasis is a parasitic disease carried by freshwater snails infected with one of the five varieties of the parasite Schistosoma, a type of trematode. Although the worms that cause schistosomiasis are not found in the...

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