Marine seismic surveys used in petroleum exploration could cause a two to three-fold increase in mortality of adult and larval zooplankton, new research published in leading science journal Nature Ecology and Evolution has found.
Scientists from IMAS and the Centre for Marine Science and Technology (CMST) at Curtin University studied the impact of commercial seismic surveys on zooplankton populations by carrying out tests using seismic air guns in the ocean off Southern Tasmania. The research found that the air gun signals, commonly used in marine petroleum exploration, had significant negative impact on the target species, causing an increase in mortality from 18 per cent to 40-60 per cent. Impacts were observed out to the maximum 1.2 kilometre range tested, 100 times greater than the previously assumed impact range of 10 metres, and all larval krill in the range were killed after the air gun's passage.
Lead author, Curtin University and CMST Associate Professor Robert McCauley, said the results raise questions about the impact of seismic testing on zooplankton and the ocean's ecosystems more widely.
"Zooplankton underpin the health and productivity of global marine ecosystems and what this research has shown is that commercial seismic surveys could cause significant disruption to their population levels," Associate Professor McCauley said.
The study, jointly funded by Curtin University and the University of Tasmania, involved two replicated experiments carried out on consecutive days using a 1.6km survey line in Storm Bay, southern Tasmania.
IMAS Associate Professor and research co-author Jayson Semmens said a series of sonar lines run perpendicular to the air gun line were monitored prior to, and immediately after the air gun run.
"These sonar runs 'imaged' the zooplankton, and showed a lowered zooplankton presence starting 15 minutes after the air gun passed, with a large 'hole' in the zooplankton evident 30 minutes after the air gun pass," Associate Professor Jayson Semmens said.
This 'hole' or region of lowered zooplankton presence was symmetric about the air gun line and increased through time.
The abundance levels of living and deceased zooplankton were also tested in the same area, before and after the seismic survey testing.
"We counted the number of live and dead zooplankton collected in nets using a special staining technique and found that two to three times as many zooplankton were dead following the air gun operations than those collected before," Associate Professor Semmens said.
Associate Professor McCauley said he hoped the research would prove useful in assisting regulatory authorities to monitor and manage marine seismic survey operations, in understanding how these surveys impact marine systems and how we may reduce such impacts.
"Plankton underpin whole ocean productivity," Associate Professor McCauley said. "Their presence impacts right across the health of the ecosystem so it's important we pay attention to their future."
Adaptations for flight may have driven egg-shape variety in birds.
This is page 352b, as numbered of 1028, in Volume 5 of the German illustrated encyclopedia Meyers Konversationslexikon, 4th edition (1885-1890), titled "Eggs of European birds. Plate I" showing 78 bird eggs as numbered 1-78, c. 1888. Published 1885-1890 in Leipzig, Germany.
The evolution of the amniotic egg -- complete with membrane and shell -- was key to vertebrates leaving the oceans and colonizing the land and air. Now, 360 million years later, bird eggs come in all shapes and sizes, from the almost perfectly spherical eggs of brown hawk- owls to the tear-drop shape of sandpipers' eggs. The question is, how and why did this diversity in shape evolve?
The answer to that question may help explain how birds evolved and solve an old mystery in natural history.
An international team of scientists led by researchers at Harvard and Princeton universities, with colleagues in the UK, Israel and Singapore, took a quantitative approach to this question. Using methods and ideas from mathematics, physics and biology, they characterized the shape of eggs from about 1,400 species of birds and developed a model that explains how an egg's membrane determines its shape. Using an evolutionary framework, the researchers found that the shape of an egg correlates with flight ability, suggesting that adaptations for flight may have been critical drivers of egg-shape variation in birds. The research is published in Science.
"Our study took a unified approach to understanding egg shape by asking three questions: how to quantify egg shape and provide a basis for comparison of shapes across species, what are the biophysical mechanisms that determine egg shape, and what are the implications of egg shape in an evolutionary and ecological setting," said senior author, L. Mahadevan, the Lola England de Valpine Professor of Applied Mathematics at the John A. Paulson School of Engineering and Applied Sciences (SEAS); Professor of Organismic and Evolutionary Biology, and of Physics at Harvard; and a Core Faculty Member of the Wyss Institute of Bioinspired Engineering at Harvard University. " We showed that egg shapes vary smoothly across species, that it is determined by the membrane properties rather than the shell, and finally that there is a strong correlation linking birds that have eggs that are elliptical and asymmetric with a strong flight ability, the last a real surprise."
The researchers began by plotting the shape -- as defined by the pole-to-pole asymmetry and the ellipticity -- of some 50,000 eggs, representing 14 percent of species in 35 orders, including two extinct orders. The researchers found that egg shape was a continuum -- with many species overlapping. The shapes ranged from almost perfectly spherical eggs to conical-shaped eggs.
So, how is this diverse spectrum of shapes formed?
Researchers have long known that egg membranes play an important role in egg shape -- after all, if an egg shell is dissolved in a mild acid, like vinegar, the egg actually maintains its shape. But how do the properties of the membrane contribute to shape?
Think of a balloon, said Mahadevan. If a balloon is uniformly thick and made of one material, it will be spherical when inflated. But if it is not uniform, all manner of shapes can be obtained.
"Guided by observations that show that the membrane thickness varies from pole to pole, we constructed a mathematical model that considers the egg to be a pressurized elastic shell that grows and showed that we can capture the entire range of egg shapes observed in nature," said Mahadevan.
The variations of shape come from the variation in the membrane's thickness and material properties and the ratio of the differential pressure to the stretchiness of the membrane.
The next question is, how are these forms related to the function of the bird?
The researchers looked at correlations between egg shape and traits associated with the species of bird, including nest type and location, clutch size (the number of eggs laid at a time), diet and flight ability.
"We discovered that flight may influence egg shape," said lead author Mary Caswell Stoddard, Assistant Professor of Ecology and Evolutionary Biology at Princeton University and former Junior Fellow in the Harvard Society of Fellows. "To maintain sleek and streamlined bodies for flight, birds appear to lay eggs that are more asymmetric or elliptical. With these egg shapes, birds can maximize egg volume without increasing the egg's width -- this is an advantage in narrow oviducts."
So an albatross and a hummingbird, while two very different birds, may have evolved similarly shaped eggs because both are high-powered fliers.
"It's clear from our study that variation in the size and shape of bird eggs is not simply random but is instead related to differences in ecology, including the amount of calcium in the diet, and particularly the extent to which each species is designed for powerful flight" says coauthor Dr. Joseph Tobias from Imperial College, UK.
Next, the researchers hope to observe the egg laying process in real time, to compare it to and refine their model.
Funding sources for this work include Princeton University, the L'Oreal USA For Women in Science Fellowship, the Harvard Society of Fellows, the Milton Fund, Nanyang Technological University, the Oxford Clarendon Fund, the Fulbright Commission, the Natural Environment Research Council, the MacArthur Foundation and the Radcliffe Institution.
A new Swansea University study has suggested that warming temperatures could drive sea turtles to extinction.
This research suggests that that warmer temperatures associated with climate change may lead to higher numbers of female sea turtles and increased nest failure. Photo by Kostas Papafitsoros.
The study by Dr Jacques-Olivier Laloë of the University's College of Science and published in the Global Change Biology journal, argues that warmer temperatures associated with climate change could lead to higher numbers of female sea turtles and increased nest failure, and could impact negatively on the turtle population in some areas of the world.
The effects of rising temperatures
Rising temperatures were first identified as a concern for sea turtle populations in the early 1980s as the temperature at which sea turtle embryos incubate determines the sex of an individual, which is known as Temperature-Dependent Sex Determination (TSD).
The pivotal temperature for TSD is 29°C as both males and females are produced in equal proportions - above 29°C mainly females are produced while below 29°C more males are born. Within the context of climate change and warming temperatures, this means that, all else being equal, sea turtle populations are expected to be more female-biased in the future. While it is known that males can mate with more than one female during the breeding season, if there are too few males in the population this could threaten population viability.
The new study also explored another important effect of rising temperatures: in-nest survival rates. Sea turtle eggs only develop successfully in a relatively narrow thermal range of approximately 25-35°C, so if incubation temperatures are too low the embryo does not develop but if they are too high then development fails. This means that if incubation temperatures increase in the future as part of climate warming, then more sea turtle nests will fail.
The researchers recorded sand temperatures at a globally important loggerhead sea turtle nesting site in Cape Verde over 6 years. They also recorded the survival rates of over 3,000 nests to study the relationship between incubation temperature and hatchling survival. Using local climate projections, the research team then modeled how turtle numbers are likely to change throughout the century at this nesting site.
Research results
Dr Laloë said: "Our results show something very interesting. Up to a certain point, warmer incubation temperatures benefit sea turtles because they increase the natural growth rate of the population: more females are produced because of TSD, which leads to more eggs being laid on the beaches.
"However, beyond a critical temperature, the natural growth rate of the population decreases because of an increase of temperature-linked in-nest mortality. Temperatures are too high and the developing embryos do not survive. This threatens the long-term survival of this sea turtle population."
The researchers expect that the numbers of nests in Cape Verde will increase by approximately 30% by the year 2100 but, if temperatures keep rising, could start decreasing afterwards.
The new study identifies temperature-linked hatchling mortality as an important threat to sea turtles and highlights concerns for species with TSD in a warming world. It suggests that, in order to safeguard sea turtle populations around the world, it is critical to monitor how hatchling survival changes over the next decades.
Dr Laloë said: "In recent years, in places like Florida--another important sea turtle nesting site--more and more turtle nests are reported to have lower survival rates than in the past. This shows that we should really keep a close eye on incubation temperatures and the in-nest survival rates of sea turtles if we want to successfully protect them.
"If need be, conservation measures could be put in place around the world to protect the incubating turtle eggs. Such measures could involve artificially shading turtle nests or moving eggs to a protected and temperature-controlled hatchery."
Climate change and temperature-linked hatchling mortality at a globally important sea turtle nesting site was published this week by Global Change Biology.
Researchers studied the survival and breeding behavior of the Snowy Plover, which are male-biased populations. Credit: Luke Eberhart-Phillips
Extinction risk for some species could be drastically underestimated because most demographic models of animal populations only analyse the number and fertility of females, dismissing male data as 'noise'.
An international team of researchers, including a PhD student and a professor from the Milner Centre for Evolution at the University of Bath, found that population growth in birds was very sensitive to the ratio of males to females in a population, called the adult sex ratio (ASR), which has previously been shown to affect mating behaviour. The researchers have published their findings in the prestigious science journal, Proceedings of the National Academy of Sciences.
Species with a high number of males in a population tend to be polygamous: the females typically breed with several partners in one season, leaving the males to do most of the care for their offspring. However, with a large number of males competing for fewer females, a male biased population can also lead to increased aggression and harassment of females which can reduce survival rates.
Conversely, species with a higher number of females to males have lower parental investment by fathers which can also adversely affect survival of offspring. Where numbers of each sex were evenly balanced, parents cooperated more in care of their young and breeding pairs tended to be monogamous.
The researchers looked at why an unbalanced sex ratio should develop in some birds. They studied the survival and breeding behaviour of 1,259 wild Snowy Plovers in north-western Mexico over a seven year period, a species that is typically male biased. The team found that whilst a similar number of males and females hatched, males had higher survival rates at all stages of life, but particularly at the juvenile stage, when individuals are independent of their parents but not fully grown.
These findings could impact the conservation of endangered species, since ignoring the sex ratio of a population could miscalculate the survival rates and therefore underestimate the vulnerability of species to extinction.
Luke Eberhart-Phillips with a Kittlitz’s plover. Credit: Luke Eberhart-Phillips.
Professor Tamás Székely, from the Milner Centre for Evolution at the University of Bath, said: "Our research has shown that population growth is very sensitive to changes in the survival of the limiting sex. A biased sex ratio either way can compromise population stability - too many males increases violence, whereas too many females leads to less cooperation between parents which reduces the survival of offspring.
"Current extinction models only take numbers of females into account - our research shows this approach could drastically underestimate extinction risk and states that males should also be part of the equation."
Luke Eberhart-Phillips, PhD student at Bielefeld University (Germany) and first author of the paper, said: "Our research shows that in Snowy Plovers the population is male-biased due to sex differences in survival of young individuals, rather than at birth or during adulthood.
"Therefore, the evolution of different mating systems - whether polygamous or monogamous - could be a consequence of innate sex differences in survival. In mammals, population sex ratios are typically female biased, whereas in birds, these sex ratios are usually male biased. "Based on our results, one could speculate that sex differences in survival during early life are driving these large-scale patterns and the evolution of breeding behaviours."
Familiarity with other females, geography may be crucial for reproduction.
Photo of Alaska Steller sea lions by the US Fish and Wildlife Service.
Female Steller sea lions tend to breed at or near the rookery where they were born, according to a study published June 7, 2017 in the open-access journal PLOS ONE by Kelly Hastings from the Alaska Department of Fish and Game, USA, and colleagues.
Understanding the patterns of dispersal for an animal species is critical for measuring changes in the population, which helps with conservation efforts. Previous studies have shown that Steller sea lion (Eumetopias jubatus) males tend to disperse more frequently than the females, however, little is known about the movements of breeding females.
The authors of the present study monitored 369 Steller sea lion females that had been marked as pups in the rookeries where they were born in southeastern Alaska, gathering observation and recapture data between 2001 and 2015 to assess how frequently breeding females switched rookery.
The researchers found that most female sea lions tended to breed at the rookeries where they were born, with fewer than 3 percent switching rookeries between years. When female sea lions did move to another rookery before breeding, they tended to select rookeries that were nearby and had a higher population of other sea lions.
Female sea lions' tendency to breed in the location where they were born could suggest that familiarity with neighboring females and knowledge of the topography of the site (for both giving birth to pups and foraging) could be crucial components of their reproduction and thus, the conservation of their species.
New born calf of a Friesian red and white cow. Back in 1993 there were only 17 real Friesian red and white cows left. Today, thanks to enthusiasts and a breeding program, there are about 300. Credit: Uberprutser (CC 3.0)
Reducing meat consumption and using more efficient farming methods globally are essential to stave off irreversible damage to the environmental, a new study says.
The research, from the University of Minnesota, also found that future increases in agricultural sustainability are likely to be driven by dietary shifts and increases in efficiency, rather than changes between food production systems.
Researchers examined more than 740 production systems for more than 90 different types of food, to understand the links between diets, agricultural production practices and environmental degradation. Their results are published today in the journal Environmental Research Letters.
Lead author Dr Michael Clark said: "If we want to reduce the environmental impact of agriculture, but still provide a secure food supply for a growing global population, it is essential to understand how these things are linked."
Using life cycle assessments - which detail the input, output and environmental impact of a food production system - the researchers analysed the comparative environmental impacts of different food production systems (e.g. conventional versus organic; grain-fed versus grass-fed beef; trawling versus non-trawling fisheries; and greenhouse-grown versus open-field produce), different agricultural input efficiencies (such as feed and fertilizer), and different foods.
The impacts they studied covered levels of land use, greenhouse gas emissions (GHGs), fossil fuel energy use, eutrophication (nutrient runoff) and acidification potential.
Dr Clark said: "Although high agricultural efficiency consistently correlated with lower environmental impacts, the detailed picture we found was extremely mixed. While organic systems used less energy, they had higher land use, did not offer benefits in GHGs, and tended to have higher eutrophication and acidification potential per unit of food produced. Grass-fed beef, meanwhile, tended to require more land and emit more GHGs than grain-fed beef."
However, the authors note that these findings do not imply conventional practices are sustainable. Instead, they suggest that combining the benefits of different production systems, for example organic's reduced reliance on chemicals with the high yields of conventional systems, would result in a more sustainable agricultural system.
Dr Clark said: "Interestingly, we also found that a shift away from ruminant meats like beef - which have impacts three to 10 times greater than other animal-based foods - towards nutritionally similar foods like pork, poultry or fish would have significant benefits, both for the environment and for human health.
"Larger dietary shifts, such as global adoption of low-meat or vegetarian diets, would offer even larger benefits to environmental sustainability and human health."
Co-author Professor David Tilman said: "It's essential we take action through policy and education to increase public adoption of low-impact and healthy foods, as well the adoption of low impact, high efficiency agricultural production systems.
"A lack of action would result in massive increases in agriculture's environmental impacts including the clearing of 200 to 1000 million hectares of land for agricultural use, an approximately three-fold increase in fertilizer and pesticide applications, an 80 per cent increase in agricultural GHG emissions and a rapid rise in the prevalence of diet-related diseases such as obesity and diabetes.
Professor Tilman added: "The steps we have outlined, if adopted individually, offer large environmental benefits. Simultaneous adoption of these and other solutions, however, could prevent any increase in agriculture's environmental impacts. We must make serious choices, before agricultural activities cause substantial, and potentially irreversible, environmental damage."
An ice sheet surface twice the size of California melted in one summer in what could become a regular occurrence.
Cascade of meltwater, partly frozen while flowing, at the shelf ice edge of Larsen A, western Weddell Sea, off the coast of West Antarctica. Credit: Alfred Wegener Institute/Wolf Arntz.
The West Antarctic Ice Sheet, a landbound mass of ice larger than Mexico, experienced substantial surface melt through the austral summer of 2015-2016 during one of the largest El Niño events of the past 50 years, according to scientists who had been conducting the first comprehensive atmospheric measurements in the region since the 1960s.
The science team conducting the ARM West Antarctic Radiation Experiment (AWARE) led by researchers at Scripps Institution of Oceanography at the University of California San Diego reports that the melting caused by warm air bearing moisture and extensive cloud cover was likely delivered by El Niño over the ice sheet. Melted snow was spotted over most of the Ross Ice Shelf, a thick platform of floating ice that channels about a third of the ice flowing from the West Antarctic Ice Sheet into the ocean.
The study, "January 2016 extensive summer melt in West Antarctica favoured by strong El Niño," was led by AWARE scientist Julien Nicolas of Ohio State University and appears in the June 15 issue of the journal Nature Communications.
Though clouds can often cool the surface of the planet by reflecting solar radiation back to space, they also trap heat between the cloud deck and the ground. Meteorological data gathered during AWARE found that in this instance, the latter effect was the more influential.
The finding of this joint U.S. Department of Energy (DOE) and National Science Foundation-funded project is of interest, said the scientists, because El Niño events are expected to become more common if planetary warming trends continue since surface melt enhances ice sheet instability already caused by warm ocean waters melting it from below.
"We were extraordinarily fortunate to be able to deploy state-of-the art equipment to West Antarctica just before this large melt event occurred," said AWARE principal investigator Dan Lubin, a research physicist at Scripps Oceanography. "These atmospheric measurements will help geophysical scientists develop better physical models for projecting how the Antarctic ice sheet might respond to a changing climate and influence sea level rise."
Number of days in January 2016 when surface melt was detected from passive microwave satellite observations. Credit: Image: Julien Nicolas.
Scientists had been able to see melt episodes in Antarctica via satellite during El Niño years of the past. The 2015-2016 event was the first, however, in which sophisticated instruments from the DOE's Atmospheric Radiation Measurement (ARM) Climate Research Facility installed on the ice sheet and at McMurdo Station adjacent to the nearby Ross Ice Shelf were present and able to make detailed measurements of atmospheric conditions at the time of a large-scale melt.
El Niño is characterized by the movement of warm waters to the eastern equatorial Pacific Ocean, which often influences water temperatures off California. The same climate phenomenon also directs warm marine air toward West Antarctica. The AWARE team noted that the melting took place even in the presence of a wind pattern that usually counteracts the flow of warm air. During the positive phase of the Southern Annular Mode (SAM), strong westerly winds blast around Antarctica, creating a fence of sorts that keeps the continent cold. The SAM during the 2015-2016 austral summer was strongly positive but nevertheless warm air penetrated the continent. AWARE researchers suggest that the melt might have been even more pronounced if the SAM were weak.
"In West Antarctica, we have a tug-of-war going on between the influence of El Niños and the westerly winds, and it looks like the El Niños are winning," said study co-author David Bromwich, professor of geography at Ohio State. "It's a pattern that is emerging. And because we expect stronger, more frequent El Niños in the future with a warming climate, we can expect more major surface melt events in West Antarctica."
The West Antarctic Ice Sheet rests on bedrock that is below sea level and is protected by a fringe of floating ice shelves. The melting and disintegration of these ice shelves would accelerate the flow of ice into the ocean. Were the ice sheet to melt completely, as probably occurred during the Earth's last inter-glacial period about 125,000 years ago, it contains enough mass to raise global mean sea level by three meters (11 feet).
Berkeley Lab researchers' surprising discovery is a major advance for low-cost, high-energy batteries.
Lithium-sulfur batteries have great potential as a low-cost, high-energy, energy source for both vehicle and grid applications. However, they suffer from significant capacity fading. Now scientists from the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have made a surprising discovery that could fix this problem.
In research led by Gao Liu, the team unexpectedly found that carrageenan, a seaweed derivative, acts as a stabilizer in lithium-sulfur batteries. Better stability allows for more cycling and an extended lifetime. Their study was published in the journal Nano Energy in a paper titled, "Nucleophilic substitution between polysulfides and binders unexpectedly stabilizing lithium sulfur battery."
"There's a lot of demand for energy storage, but there's very little chemistry that can meet the cost target," said Liu, the corresponding author of the paper. "Sulfur is a very low-cost material--it's practically free. And the energy capacity is much higher than that of lithium-ion. So lithium-sulfur is one chemistry that can potentially meet the target."
Rechargeable lithium-sulfur batteries have some limited commercial applications currently, but the "critical killer" in the chemistry is that the sulfur starts to dissolve, creating what is called the polysulfide shuttling effect. In trying to address this problem, Liu was experimenting with the binder, which is the substance that holds all the active materials in a battery cell together.
"A binder is like glue, and normally battery designers want a glue that is inert," Liu said. "This binder we tried worked really well. We asked why, and we discovered it's reacting¬--it reacted immediately with the polysulfide. It formed a covalent bonding structure."
By chemically reacting with the sulfur, the binder was able to stop it from dissolving. Once the researchers figured that out, they looked around for a naturally occurring material that would do the same thing. They landed upon carrageenan, a substance extracted from red seaweeds and in the same functional group (or group of atoms, with similar chemical reactivity) as the synthetic polymer they used in their initial experiments.
"We looked for something that was economical and readily available," Liu said. "It turns out carrageenan is used as a food thickener. And it actually worked just as well as the synthetic polymer--it worked as a glue and it immobilized the polysulfide, making a really stable electrode."
Carrageenan, an unexpected battery stabilizer, is extracted from red seaweed. Credit: DeborahMaxemow.
Visualizing in situ reactions
Liu worked with Jinghua Guo of Berkeley Lab's Advanced Light Source, one of the world's brightest sources of ultraviolet and soft X-ray beams, to make his discovery.
"The light source provides unique X-ray based tools," Guo said. "We want the tool to monitor the electrochemistry simultaneously while the battery is charging. In this case, we made a dedicated battery cell with the materials, then used X-rays to monitor the process under in situ conditions."
Liu added: "You can't do this kind of experiment anywhere else. In this case we have a unique beamline to detect sulfur. It's always a lot of effort to design the tool for in situ. Ex situ is easy, but in this case, ex situ didn't give you the result. With the in situ cell, we were able to watch where the sulfur goes. Turns out, it doesn't go anywhere. That was really cool."
General Motors, an industry research partner of Berkeley Lab's Energy Storage & Distributed Resources Division, confirmed Liu's research findings. "They independently tested it and saw the same effect we saw--in fact the stability was even better," Liu said.
Berkeley Lab battery scientist Gao Liu.
Radical departure
The results open up an entirely new way of thinking about battery chemistry, Liu noted. "Scientifically, it's a totally different concept, of a binder that is reactive rather than inert," he said. "People don't think that way. They think a binder's function is to physically hold things together. We found, no, we need a way to chemically bind the polysulfide."
Liu and his group have been working on lithium-sulfur batteries for several years. They published a paper in Nano Letters last year on a novel lithium-sulfur electrode structure based on nature's own superefficient ant nest.
With this breakthrough to stabilize lithium-sulfur batteries¬ Liu is now seeking to improve the lifetime of lithium-sulfur batteries even further. "We want to get to thousands of cycles," he said.
Lithium-sulfur batteries have more than twice the energy density of lithium-ion batteries, which now dominate the market. They are also much more lightweight so they have potential application in airplanes and drones. In fact, lithium-sulfur batteries provided nighttime power in the record-setting 14-day solar-powered flight of the Zephyr, an unmanned aircraft, in 2010.
Liu, Guo, and their team will continue to work on understanding the chemical reactions in the cell. "After this polymer binds with sulfur, what happens next? How does it react with sulfur, and is it reversible?" Liu said. "Understanding that will allow us to be able to develop better ways to further improve the life of lithium-sulfur batteries."
Building the hundreds of hydroelectric dams proposed for the Amazon River Basin will cause massive environmental damage all the way from the eastern slopes of the Andes to the Atlantic Ocean, according to new findings by an international team of researchers that includes a University of Arizona hydrologist.
The Amazon River and its watershed--the largest river system on Earth--cover 6.1 million square kilometers (2.4 million square miles) and includes nine countries.
"The Amazon is the most important river basin on the planet. It's a microcosm of our issues of today involving environment, energy and health of the planet," said co-author Victor Baker, University of Arizona Regents' Professor of Hydrology and Atmospheric Sciences.
The 428 current and proposed dams will have environmental impacts throughout the entire system, the team reports in the June 15 issue of the journal Nature. About one-third of the 428 dams are built or are under construction.
While these hydroelectric dams have been justified for providing renewable energy and avoiding carbon emissions, little attention has been paid to the major disturbances dams present to the Amazon floodplains, rainforests, the northeast coast of South America and the regional climate, the researchers write.
Generally, only the local environmental impact of a dam is considered, not the regional or system-wide effect.
"The river and its individual pieces cannot be separated out," Baker said. "That an individual dam assessment can be separated from the rest of the system isn't scientifically valid."
The research team conducted a large-scale assessment of how the current and future dams will affect the entire Amazon Basin. The researchers developed a Dam Environmental Vulnerability Index to quantify their assessment. The DEVI ranges from one to 100, with 100 being the most vulnerable.
The DEVI incorporates overall changes to the river systems from dams, including the potential land use changes, erosion, runoff, changes in sediment deposition, the effects on the region's rich biodiversity and impacts to the regional food supply.
The researchers found the watershed of the Madeira River, the largest Amazon tributary, will sustain the greatest negative impacts from the current and future dams. The team assigned that region a DEVI above 80.
This map of South America shows the watershed of the Amazon River, the largest river system on Earth. The watershed, which stretches from the eastern slopes of the Andes to the Atlantic coast, covers 6.1 million square kilometers (2.4 million square miles) and includes nine countries. Credit: Earth Observatory, NASA.
This map shows the Dam Environmental Vulnerability Index for various areas of the Amazon Basin. The DEVI incorporates multiple measures of the environment to show how vulnerable an area is to damage from dam-building. The most vulnerable area is the Madeira River watershed, shown in red (DEVI of 80-100), following by the areas colored salmon pink (DEVI of 60-80). The darker blue regions are the least vulnerable areas (DEVI of 0-20). The green dots show the location of dams that are existing and under construction. The yellow dots represent dams that are planned. Credit: Edgardo Latrubesse, The University of Texas at Austin.
Lead author Edgardo Latrubesse, a geography and the environment professor at the University of Texas at Austin, said, "The impacts can be not only regional, but also on an interhemispheric scale. If all the planned dams in the basin are constructed, their cumulative effect will trigger a change in sediment flowing into the Atlantic Ocean that may hinder the regional climate."
The paper by Latrubesse, Baker and their 14 colleagues is titled, "Damming the Rivers of the Amazon Basin." A complete list of authors and their affiliations is at the bottom of this news release.
The National Science Foundation, NASA, the National Geographic Society, LLILAS-Mellon, the Brazilian Council for Scientific and Technological Development-CNPq and CAPES Foundation funded the research.
Rivers in the Amazon Basin move like a dance, exchanging sediments across continental distances to deliver nutrients to a mosaic of wetlands, Latrubesse said.
Sediment transported by rivers provides nutrients that sustain wildlife, contribute to the regional food supplies and modulate river dynamics that result in high habitat and biotic diversity for both aquatic and nonaquatic organisms.
Many current and proposed dams are located far upstream in the Andean region. Research indicates the Andes provide more than 90 percent of the sediment to the entire Amazon Basin. Dams trap the nutrient-rich sediment and prevent it from moving downstream.
The Madeira River is home to the most diverse fish population in the Amazon. Since the huge Santo Antônio and Jiaru dams were constructed on the Madeira, the river's average sediment concentration decreased by 20 percent. Researchers expect the 25 dams planned for further upstream will trap additional nutrient-rich sediment behind them.
The largest preserved mangrove region of South America is along the coastline of northeast Brazil and the three Guianas and needs sediment from the Amazon, Latrubesse said.
Baker added that the cumulative impacts from the dams affect rainfall and storm patterns from the Amazon Basin to the Gulf of Mexico. In addition to changes in sediment flow, those impacts include the storage of water behind the dams, the water flows and the timing of flows to the mouth of the river.
The study's authors conclude, "Citizens of the Amazon Basin countries will ultimately have to decide whether hydropower generation is worth the price of causing profound damage to the most diverse and productive river system in the world. If those decisions are made within the context of a comprehensive understanding of the fluvial system as a whole, the many benefits the rivers provide to humans and the environment could be retained."
The first public sharing of government data marks a victory for transparency in an opaque industry where research and sustainable management have suffered from a lack of information on where fishing happens and how fishers interact with ocean resources.
Fishing boat in Sumatra, Indonesia. Credit: James Gagen (CC 2.0).
This week, at the United Nation's Ocean Conference, the Republic of Indonesia becomes the first nation ever to publish Vessel Monitoring System (VMS) data revealing the location and activity of its commercial fishing fleet. The new data being made public on the Global Fishing Watch public mapping platform reveals commercial fishing in Indonesian waters and areas of the Indian Ocean where it had previously been invisible to the public and other nations.
Susi Pudjiastuti, the Minister of Fisheries and Marine Affairs for the Republic of Indonesia, is taking a bold step toward increasing transparency in her country's fishing industry. Today she urges other nations to do the same.
"Illegal fishing is an international problem, and countering it requires cross border cooperation between countries," says Minister Susi. "I urge all nations to join me in sharing their vessel monitoring data with Global Fishing Watch. Together, we can begin a new era in transparency to end illegal and unreported fishing."
Also at the UN Ocean's Conference, Global Fishing Watch has committed to host any country's VMS data, calling on other governments to follow Indonesia's lead. "We believe publicly shared VMS will become a powerful new standard for transparent operation in commercial fishing," says Paul Woods, Global Fishing Watch CEO and Chief Technology Officer for SkyTruth, a founding partner of Global Fishing Watch along with Oceana and Google. "SkyTruth has been collaborating with the Indonesian government for the past two years to really understand their VMS data and find new ways for VMS to enhance their fisheries management."
Working closely with Oceana toward a united goal of transparency at sea, Peru becomes the first nation to follow Indonesia's lead. Vice Minister for Fisheries and Aquaculture, Hector Soldi, announced Peru's intent to publicly share their VMS data in Global Fishing Watch.
"We applaud the commitments made by Peru and Indonesia to publish their previously private vessel tracking data and encourage other countries to follow their lead," said Jacqueline Savitz, Senior Vice President for the United States and Global Fishing Watch at Oceana. "Together, with forward-thinking governments like these, we can bring even greater transparency to the oceans. By publishing fishing data and using Global Fishing Watch, governments and citizens can unite to help combat illegal fishing worldwide. With more eyes on the ocean, there are fewer places for illegal fishers to hide."
Global Fishing Watch uses publicly broadcast Automatic Identification System (AIS) signals from ships at sea to reveal the activity of the majority of all industrial-sized commercial fishing vessels (those exceeding a capacity of 100 Gross Tons which average around 24 meters). The inclusion of government-owned VMS data adds detailed information on smaller commercial fishing vessels that are not required to carry AIS, and are therefore not reliably trackable by any other means. Indonesian regulations require VMS on fishing vessels with a capacity equal to or exceeding 30 Gross Tons (averaging about 16 meters or more). Indonesia is the second-largest producer of wild-caught seafood in the world, and Indonesian VMS alone adds nearly 5,000 fishing vessels to Global Fishing Watch's existing database of 60,000 vessels. "It's remarkable to see how adding in all these medium sized vessels with VMS really fills in the picture for large chunks of the ocean where we knew there was fishing, but just couldn't see it with AIS alone," says Woods. "It is also revealing new areas where we weren't aware fishing occurs."
Google's lead on Global Fishing Watch, Brian Sullivan, says that the platform is built using the latest cloud and machine learning technologies and can easily incorporate additional data sources or methodologies. "The ability to scale rapidly as new countries and providers join means we can move from raw data to quickly producing dynamic visualizations and reporting that promote scientific discovery and support policies for better fishery management," he said. "With Indonesia and Peru, two of the world's top five fishing nations, committed to a new age of transparency in the fishing industry, Google is committed to fostering international cooperation."
Because fishing occurs over the horizon and out of sight, the industry remains one of the most opaque in the world. The lack of knowledge about how much fish is being taken from the ocean, and who is fishing where severely hinders effective management. It also facilitates rampant Illegal, Unreported and Unregulated (IUU) fishing that threatens fish stocks, food security and the economies of coastal nations that depend on seafood for food, jobs and foreign export dollars.
Gains in transparency through the sharing of government VMS data will not only curb IUU, but will benefit the fishing industry as public demand for information about the source of their seafood increases and open data sharing through Global Fishing Watch provides validation of product source. These partnerships with Indonesia and Peru set a new bar for transparency at sea. Making this data publicly available will support regional cooperation in monitoring, surveillance and enforcement, reduce opportunities for corruption, and enable more informed management decisions.
In addition to committing to support any nation willing to share its VMS data publicly, Global Fishing Watch joined 50 members of the tuna industry and 17 other civil society organization to endorse the World Economic Forum Tuna Traceability 2020 Declaration made at the UN Oceans Conference.
*SkyTruth's work with the Indonesian Ministry of Fisheries and Marine Affairs has been made possible through support from the Packard Foundation and the Walton Family Fund. Global Fishing Watch is an independent 501c3 that was founded and supported by Oceana, SkyTruth and Google.
Oceana:
Oceana is the largest international advocacy organization dedicated solely to ocean conservation. Oceana is rebuilding abundant and biodiverse oceans by winning science-based policies in countries that control one third of the world's wild fish catch. With over 100 victories that stop overfishing, habitat destruction, pollution and killing of threatened species like turtles and sharks, Oceana's campaigns are delivering results. A restored ocean means that one billion people can enjoy a healthy seafood meal, every day, forever. Together, we can save the oceans and help feed the world.
SkyTruth:
SkyTruth is a nonprofit organization using remote sensing and digital mapping to create stunning images that expose the environmental impact of natural resource extraction and other human activities. We use satellite imagery and geospatial data to create compelling and scientifically credible visuals and resources to inform environmental advocates, policy-makers, the media, and the public.
Google:
Google Earth Outreach is a team dedicated to leveraging and developing Google's infrastructure to address environmental and humanitarian issues through partnerships with non-profits, educational institutions, and research groups.
