July 1, 2006 — Manmade and natural sounds, from boat engines to rainfall, sound different below the sea surface. To study their impact of noise on marine life, scientists are submerging devices called Passive Aquatic Listeners, or PALs, at depths of up to hundreds of meters deep in oceans around the globe. PALs could also help track whales and other marine life.
What do boats, whales and rainfall sound like from underneath the surface of the sea? How does it affect everything that lives down there?
Jeffrey Nystuen, a physical and acoustical oceanographer at University of Washington in Seattle developed PALs, or Passive Aquatic Listeners.
"By listening passively to the underwater sound field, we learn a lot about the environment," Nystuen tells DBIS.
Researchers submerge PALs from 10 to hundreds of meters below the sea's surface. They record a few seconds of sound about every 10 minutes. Nystuen says: "You can listen for bubbles. You can listen for whales. You can listen for ships and sonars."
PALs have been submerged at locations around the world and are in place for one year. The recordings can help scientists measure wind speed or rainfall at sea -- and learn more about the wildlife. They can also help biologists identify when and where there are large groups of whales and other marine life.
Other scientists say the impacts of man-made sounds on the marine environment are of a concern and passive acoustic monitoring is a valuable tool.
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BACKGROUND: Physical oceanographer Jeff Nyustuen is giving scientists and managers a way to sift through and identify the sounds present in various marine ecosystems. Passive Aquatic Listeners (PALS) are devices that sink ten to thousands of meters below the water surface and are set to listen for a few seconds every few minutes. PALs can identify sounds coming from such things as ships, whales, volcanic eruptions, rainfall and breaking waves. The result is a record of all the noise and its intensity in the ocean environment, which can help biologists sort out what levels of noise go unnoticed, or can cause harm to marine mammals, for example.
HOW IT WORKS: PALs don't try to record every single sound in the ocean. That would take too much memory. Instead, Nyusten is developing software that allows the PALs to sift through the racket, identify and sort sound sources by frequencies as they are received.
ABOUT SOUND: Sound waves are pressure waves: the result of a vibrating object that creates a disturbance in the surrounding air. For instance, when the telephone rings, the ringer vibrates very quickly, sending energy radiating outward through the air. These vibrations disturb the molecules that make up the air. The air molecules push closer together as the object moves one way ý an effect known as compression -- and then create a space between themselves and the vibrating object as it moves the other way, called rarefaction. The motion disturbs the neighboring molecules in turn, creating an outward ripple effect, much like a stone cast in a quiet pond will cause waves to ripple outward from the spot where the stone hit.
WHAT'S YOUR FREQUENCY? All sound waves have wavelength and frequency. The distance between compressions determines the wavelength. Objects that vibrate very quickly create short wavelengths because there is very little space between the compressions, creating a high-pitched sound. Objects that vibrate very slowly create long wavelengths because the compressions are spaced further apart. This creates a low-pitched sound. Frequency measures how many crests, or compressions, occur within one second; the measurement of this speed of vibration is called a Hertz, and 1 Hertz is equivalent to 1 vibration per second. Pitch simply means those frequencies within the range of human hearing (from about 20 Hertz to 20,000 Hertz). The faster the rate of vibration, the higher the pitch; the slower the rate of vibration, the lower the pitch.
SOUND SENSE: Bats emit a series of ultrasonic pulses that bounce off objects in its environment. How long it takes for the sound to be reflected back to the bat indicates how close (or far) a given object might be, enabling the bat to orient itself as it flies, and to detect food. Modern sonar technology is based on the same principle. The more feedback the bat receives, in terms of incoming reflections, the more accurately it can pinpoint a given object's location That's why the rate of the ultrasonic calls increases as the bat nears its prey, climaxing into a "feeding buzz" as the bat locks in on its target and prepares to strike. In contrast, whales appear to use sounds (or "songs") to communicate, emitting a complex sequence of low moans, high squeals and clicking noises that can last as long as 30 minutes. The songs appear to be related to mating cycles.
STOP THAT RACKET: Noise cancellation tries to block the unwanted sound at its source, rather than merely trying to prevent it from entering our ears. If we add two waves together, and the peaks of one line up with the valleys of the other, they will cancel each other out. Digital signal processors (DSPs) are microelectronic devices that determine which sound wave is required to cancel the unwanted sound wave (noise). It then creates that sound and amplifies it through speakers or headphones. The end result is near silence. Most cell phones, CD players, and hearing aids now contain one or more DSP devices.
The American Astronomical Society and the Acoustical Society of America contributed to the information contained in the video portion of this report.
Friday, November 14, 2008
Underwater Earthquakes Geophysicists Discover Slippery Secret Of Weaker Underwater Earthquakes
October 1, 2007 — Seismologists investigating undersea earthquakes have found that molten rock lubricates faults. This decreases the amount of friction between sides of the fault and decreases the intensity of earthquakes. They also found that the fragmentation of fault lines along the seafloor contributes an earthquake-dampening effect
In December 2004, an underwater earthquake triggered a string of tsunamis along the Indian Ocean with devastating effects. Now, scientists have found ways nature is preventing some deep ocean earthquakes and save lives. Strong underwater earthquakes start off silent -- until their tsunami waves roar on shore, destroying property and lives.
But now, geophysicists and oceanographers have found a break in studying sea floor faults. Faults aren't one continuous line. Instead, they are broken up into sections and the edges of the faults are full of cracks as the earth's crust on both sides of the fault slides past each other.
"Large scale earthquakes don't occur on the sea faults," explains Patricia Gregg, graduate student from M.I.T. and Woods Hole Oceanographic Institution Joint Program in Oceanography in Woods Hole, Mass.
Molten rock -- or magma -- from under-sea volcanoes lubricates the fault, reducing the amount of friction that could cause another earthquake. By analyzing data collected by sea vessels, they discovered volcanic activity may be weakening fault lines. The hot rock could be serving as a geological lubricant, making the fault line more malleable. Less friction means less of a quake. "So, the scale of the earthquake is smaller because the volcanism warms up the fault line and makes it more difficult to break rocks," Gregg says.
"Our ultimate purpose is to forecast earthquakes on land because earthquakes cause so much damage and kill so many people," says Jian Lin, Ph.D., senior scientist in the Department of Geology & Geophysics at Woods Hole Oceanographic Institution.
By understanding what happens below the Earth's surface, geophysicists are hoping to be able to send a warning to those above-ground. The researchers say it is easier to study fault lines below sea level. They are simple in their geology and history. Fault lines on land have layers of history that make it harder to understand the physics of how they began.
The Incorporated Research Institutions for Seismology and the American Geophysical Union contributed to the information contained in the TV portion of this report.
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BACKGROUND: Many earthquakes in the deep ocean are much smaller in magnitude than expected. Geophysicists from the Woods Hole Oceanographic Institute (WHOI) have found new evidence that the fragmented structure of seafloor faults, along with previously unrecognized volcanic activity, may be dampening the effects of these quakes.
ABOUT THE STUDY: The WHOI scientists examined data on ocean transform faults collected by ships and satellites from 19 locations in the Atlantic, Pacific and Indian oceans, augmented with bathymetry maps. Ocean transform faults are fractures in the rock of the ocean floor along which horizontal motion occurs. They cut across the mid-ocean ridge system, a 40,000 mile long mountainous seam in the Earth's crust that marks the edges of the planet's tectonic plates. The mid-ocean ridges are like the seams on a baseball, and the transform faults are like the red stitching, lying perpendicular to the ridge. These faults help accommodate the motion of the tectonic plates, cracking at the edges as the different pieces of rocky crust slip past each other. Along some plates, new crust is formed, while along others, old crust is driven back down into the earth.
WHAT THEY FOUND: The largest quakes at mid-ocean ridges tend to occur at transform faults, yet the WHOI scientists found that earthquakes along the seafloor faults on the East Pacific Rise were not as large in magnitude, or resonating with as much energy as they ought to, considering the length of these faults. Conventional wisdom has held that transform faults should contain rocks that are colder, denser and heavier than the new crust being formed at the mid-ocean ridge. In contrast, the mid-ocean ridge should have a lower density because the crust is lighter than the underlying mantle rocks and thicker along the ridge, and the newer molten rock is less dense. But the WHOI scientists found that, surprisingly, the faults were not more dense -- rather, many fault zones seemed to have lighter rock within and beneath the faults.
WHAT'S GOING ON? The WHOI scientists believe that many of the transform fault lines on the ocean floor are not as continuous as they first appear from looking at low-resolution maps. Instead, they are fragmented into smaller pieces, making the length of any given earthquake rupture on the seafloor shorter -- so the earthquake travels less distance along the surface. It is also possible that magma (molten rock) from inside the earth is rising up beneath the faults. Molten rock is less brittle and more malleable, and could be dampening the strains and jolts as the plate crusts rub together, serving as a geological lubricant. Both phenomena appear to prevent earthquakes from spreading across the seafloor, thus reducing their magnitude and impact.
WHAT CAUSES EARTHQUAKES? An earthquake is the result of a sudden release of stored energy in the Earth's crust triggered by shifting tectonic plates. The Earth's lithosphere is an elaborate network of interconnected plates that move constantly -- far too slow for us to be aware of them, but moving, nonetheless. Occasionally they lock up at the boundaries, and this creates frictional stress. When that gets to be too large a strain, the rocks give way and break and slide along fault lines. This can give rise to a violent displacement of the Earth's crust, which we feel as vibrations or tremors as the pent-up energy is released. However, only 10% or so of the total energy is released in the seismic waves. However, the rest is converted into heat, used to crush and deform rock, or released as friction.
In December 2004, an underwater earthquake triggered a string of tsunamis along the Indian Ocean with devastating effects. Now, scientists have found ways nature is preventing some deep ocean earthquakes and save lives. Strong underwater earthquakes start off silent -- until their tsunami waves roar on shore, destroying property and lives.
But now, geophysicists and oceanographers have found a break in studying sea floor faults. Faults aren't one continuous line. Instead, they are broken up into sections and the edges of the faults are full of cracks as the earth's crust on both sides of the fault slides past each other.
"Large scale earthquakes don't occur on the sea faults," explains Patricia Gregg, graduate student from M.I.T. and Woods Hole Oceanographic Institution Joint Program in Oceanography in Woods Hole, Mass.
Molten rock -- or magma -- from under-sea volcanoes lubricates the fault, reducing the amount of friction that could cause another earthquake. By analyzing data collected by sea vessels, they discovered volcanic activity may be weakening fault lines. The hot rock could be serving as a geological lubricant, making the fault line more malleable. Less friction means less of a quake. "So, the scale of the earthquake is smaller because the volcanism warms up the fault line and makes it more difficult to break rocks," Gregg says.
"Our ultimate purpose is to forecast earthquakes on land because earthquakes cause so much damage and kill so many people," says Jian Lin, Ph.D., senior scientist in the Department of Geology & Geophysics at Woods Hole Oceanographic Institution.
By understanding what happens below the Earth's surface, geophysicists are hoping to be able to send a warning to those above-ground. The researchers say it is easier to study fault lines below sea level. They are simple in their geology and history. Fault lines on land have layers of history that make it harder to understand the physics of how they began.
The Incorporated Research Institutions for Seismology and the American Geophysical Union contributed to the information contained in the TV portion of this report.
show background -->
BACKGROUND: Many earthquakes in the deep ocean are much smaller in magnitude than expected. Geophysicists from the Woods Hole Oceanographic Institute (WHOI) have found new evidence that the fragmented structure of seafloor faults, along with previously unrecognized volcanic activity, may be dampening the effects of these quakes.
ABOUT THE STUDY: The WHOI scientists examined data on ocean transform faults collected by ships and satellites from 19 locations in the Atlantic, Pacific and Indian oceans, augmented with bathymetry maps. Ocean transform faults are fractures in the rock of the ocean floor along which horizontal motion occurs. They cut across the mid-ocean ridge system, a 40,000 mile long mountainous seam in the Earth's crust that marks the edges of the planet's tectonic plates. The mid-ocean ridges are like the seams on a baseball, and the transform faults are like the red stitching, lying perpendicular to the ridge. These faults help accommodate the motion of the tectonic plates, cracking at the edges as the different pieces of rocky crust slip past each other. Along some plates, new crust is formed, while along others, old crust is driven back down into the earth.
WHAT THEY FOUND: The largest quakes at mid-ocean ridges tend to occur at transform faults, yet the WHOI scientists found that earthquakes along the seafloor faults on the East Pacific Rise were not as large in magnitude, or resonating with as much energy as they ought to, considering the length of these faults. Conventional wisdom has held that transform faults should contain rocks that are colder, denser and heavier than the new crust being formed at the mid-ocean ridge. In contrast, the mid-ocean ridge should have a lower density because the crust is lighter than the underlying mantle rocks and thicker along the ridge, and the newer molten rock is less dense. But the WHOI scientists found that, surprisingly, the faults were not more dense -- rather, many fault zones seemed to have lighter rock within and beneath the faults.
WHAT'S GOING ON? The WHOI scientists believe that many of the transform fault lines on the ocean floor are not as continuous as they first appear from looking at low-resolution maps. Instead, they are fragmented into smaller pieces, making the length of any given earthquake rupture on the seafloor shorter -- so the earthquake travels less distance along the surface. It is also possible that magma (molten rock) from inside the earth is rising up beneath the faults. Molten rock is less brittle and more malleable, and could be dampening the strains and jolts as the plate crusts rub together, serving as a geological lubricant. Both phenomena appear to prevent earthquakes from spreading across the seafloor, thus reducing their magnitude and impact.
WHAT CAUSES EARTHQUAKES? An earthquake is the result of a sudden release of stored energy in the Earth's crust triggered by shifting tectonic plates. The Earth's lithosphere is an elaborate network of interconnected plates that move constantly -- far too slow for us to be aware of them, but moving, nonetheless. Occasionally they lock up at the boundaries, and this creates frictional stress. When that gets to be too large a strain, the rocks give way and break and slide along fault lines. This can give rise to a violent displacement of the Earth's crust, which we feel as vibrations or tremors as the pent-up energy is released. However, only 10% or so of the total energy is released in the seismic waves. However, the rest is converted into heat, used to crush and deform rock, or released as friction.
Rip Current Secrets Revealed Oceanographers Uncover The Physics Of Rip Currents
August 1, 2006 — Rip currents flow in very erratic patterns, not in steady courses as previously believed -- which may help explain why they can be so dangerous even for experienced swimmers. Oceanographers have discovered the behavior by tracking the motion of colored dye added to a wave pool generating rip currents.
NEWARK, Del. -- Each year, an estimated 100 people drown in ocean rip currents. A strong current can sweep even the strongest swimmer out to sea. Researchers are now making waves studying rip currents, revealing the life-saving information you need to know about these dangerous ocean currents.
There's something lurking in the ocean -- creating panic in even the best swimmers!
"It came really quick, like we went under a wave, and then the next thing we know it was just, like, pulling us out," says 18-year old Phoebe Brown. Not a shark, it's a rip current. And it can drag unsuspecting swimmers out to sea, up to eight feet per second.
Rip currents form at breaks in sandbars hidden underwater, creating a strong channel of water that pulls anything in its path far away from shore. Traditionally, oceanographers believed rip currents had a steady, uniform course. Now, new research shows the flow of water moves in an erratic pattern.
Oceanographer James Kirby, Jr, says, "Flow patterns get very, very complicated and very, very unpredictable, and we're trying to come to an understanding of what causes all that complication."
In a study at the University of Delaware in Newark, Kirby added colored dye to a wave pool generating rip currents. The dye's course is recorded as it moves through the current. The dye's movement shows an irregular rip current pattern -- making it more difficult to escape.
"It's very difficult for a swimmer once he's actually caught in the flow even to establish a sense of orientation and decide which way to swim," Kirby tells DBIS. He also says some rip currents can last for weeks and even months at a time, in the same location.
To avoid unpredictable rip currents, keep an eye out for signs of one, like broken wave patterns and discolored water. If you end up caught in a rip current...
"Number one is don't panic," says Jesse Steele, a lifeguard at Bethany Beach in Delaware. "Swim parallel to shore."
show background -->
BACKGROUND: A professor at the University of Delaware has created a comprehensive computer model that predicts the physical processes in the area from the high tide mark on shore to a depth of 10 meters, called the nearshore ocean.Wave weight, current movement and naturally occurring sediment transport, are analyzed by computers to from a computer model. The model allows weather forecasters to quickly predict dangerous surf conditions and issue immediate warnings. It can even predict some dangerous events weeks before they occur. Swimmers and life guards have more tools to identify rip currents, for example. The model would also be useful for builders designing shore properties.
WHAT ARE RIP CURRENTS? A rip current is a strong flow of water returning seaward along the shore. When wind and waves push water to the shore, the previous backwash is often pushed sideways by the oncoming waves. The backwash streams along the shoreline until it finds an exit back to the sea. The resulting rip current is usually narrow and located in trenches between sandbars, under piers, or along jetties. The current is strongest at the surface and can dampen incoming waves, which might make the area seem deceptively calm. That's one thing to look for when searching for rip currents: unusually calm waters. The color of the water may be different from the surrounding area, and the waterline will be lower on the shore near a rip current.
IT'S NOT THE UNDERTOW: Many of the deaths resulting from rip currents are wrongly attributed to an undertow. The two are related, but distinct. Rip currents occur if there's a place along the beach where the incoming waves aren't as strong, so that the escaping water goes through that weak spot. If there is no spot with weaker surf, the accumulated water flows down and under the waves and back out to sea, forming an undertow.
TIDES AND THE MOON: Rip currents are sometimes erroneously called "rip tides." They are not tides, although particularly low tides can lead to stronger rip currents. What are tides? The strength of gravity depends on the distance from the source; the closer you are, the stronger the "pull" that you feel. The moon's gravity acts on the earth, but the diameter of the earth is large enough compared to the distance of the moon that one side of our planet -- the one nearer the moon -- feels the moon's gravity much more strongly than the side further away from the moon. In effect, the earth is "stretched" by the difference in the moon's gravity across the earth, and this gives rise to the tides. That's why there are two tidal bulges on the earth, one on the near side, and one on the far side.
SAFETY TIPS: The most common advice for escaping a rip current is not to panic and try to swim against the current directly back to shore. People become exhausted very quickly and can easily drown. Instead, you should swim parallel to the beach and then let the waves bring you into shore.
NEWARK, Del. -- Each year, an estimated 100 people drown in ocean rip currents. A strong current can sweep even the strongest swimmer out to sea. Researchers are now making waves studying rip currents, revealing the life-saving information you need to know about these dangerous ocean currents.
There's something lurking in the ocean -- creating panic in even the best swimmers!
"It came really quick, like we went under a wave, and then the next thing we know it was just, like, pulling us out," says 18-year old Phoebe Brown. Not a shark, it's a rip current. And it can drag unsuspecting swimmers out to sea, up to eight feet per second.
Rip currents form at breaks in sandbars hidden underwater, creating a strong channel of water that pulls anything in its path far away from shore. Traditionally, oceanographers believed rip currents had a steady, uniform course. Now, new research shows the flow of water moves in an erratic pattern.
Oceanographer James Kirby, Jr, says, "Flow patterns get very, very complicated and very, very unpredictable, and we're trying to come to an understanding of what causes all that complication."
In a study at the University of Delaware in Newark, Kirby added colored dye to a wave pool generating rip currents. The dye's course is recorded as it moves through the current. The dye's movement shows an irregular rip current pattern -- making it more difficult to escape.
"It's very difficult for a swimmer once he's actually caught in the flow even to establish a sense of orientation and decide which way to swim," Kirby tells DBIS. He also says some rip currents can last for weeks and even months at a time, in the same location.
To avoid unpredictable rip currents, keep an eye out for signs of one, like broken wave patterns and discolored water. If you end up caught in a rip current...
"Number one is don't panic," says Jesse Steele, a lifeguard at Bethany Beach in Delaware. "Swim parallel to shore."
show background -->
BACKGROUND: A professor at the University of Delaware has created a comprehensive computer model that predicts the physical processes in the area from the high tide mark on shore to a depth of 10 meters, called the nearshore ocean.Wave weight, current movement and naturally occurring sediment transport, are analyzed by computers to from a computer model. The model allows weather forecasters to quickly predict dangerous surf conditions and issue immediate warnings. It can even predict some dangerous events weeks before they occur. Swimmers and life guards have more tools to identify rip currents, for example. The model would also be useful for builders designing shore properties.
WHAT ARE RIP CURRENTS? A rip current is a strong flow of water returning seaward along the shore. When wind and waves push water to the shore, the previous backwash is often pushed sideways by the oncoming waves. The backwash streams along the shoreline until it finds an exit back to the sea. The resulting rip current is usually narrow and located in trenches between sandbars, under piers, or along jetties. The current is strongest at the surface and can dampen incoming waves, which might make the area seem deceptively calm. That's one thing to look for when searching for rip currents: unusually calm waters. The color of the water may be different from the surrounding area, and the waterline will be lower on the shore near a rip current.
IT'S NOT THE UNDERTOW: Many of the deaths resulting from rip currents are wrongly attributed to an undertow. The two are related, but distinct. Rip currents occur if there's a place along the beach where the incoming waves aren't as strong, so that the escaping water goes through that weak spot. If there is no spot with weaker surf, the accumulated water flows down and under the waves and back out to sea, forming an undertow.
TIDES AND THE MOON: Rip currents are sometimes erroneously called "rip tides." They are not tides, although particularly low tides can lead to stronger rip currents. What are tides? The strength of gravity depends on the distance from the source; the closer you are, the stronger the "pull" that you feel. The moon's gravity acts on the earth, but the diameter of the earth is large enough compared to the distance of the moon that one side of our planet -- the one nearer the moon -- feels the moon's gravity much more strongly than the side further away from the moon. In effect, the earth is "stretched" by the difference in the moon's gravity across the earth, and this gives rise to the tides. That's why there are two tidal bulges on the earth, one on the near side, and one on the far side.
SAFETY TIPS: The most common advice for escaping a rip current is not to panic and try to swim against the current directly back to shore. People become exhausted very quickly and can easily drown. Instead, you should swim parallel to the beach and then let the waves bring you into shore.
Octopus Family Tree Traced Using New Molecular Evidence
Megaleledon setebos, the closest living relative of the octopuses' common ancestor. (Credit: Census of Marine Life)
ScienceDaily (Nov. 13, 2008) — Octopuses started migrating to new ocean basins more than 30 million years ago as Antarctica cooled and large ice-sheets grew.
These huge climatic events created a 'thermohaline expressway' - a northbound flow of deep cold water, providing new habitat for the animals previously confined to the sea floor around Antarctica, according to new research led by Dr Louise Allcock at Queen's School of Biological Sciences and colleagues from Cambridge University and British Antarctic Survey.
Isolated in new habitat conditions, many different species evolved. Some octopuses lost their defensive ink sacs because there was no need for the defence mechanisms in the pitch black waters more than two kilometres below the surface.
Dr Allcock, who was assisted on the study by Dr Jan Strugnell and Dr Paulo Prodöhl from Queen's, said: "It is clear from our research that climate change can have profound effects on biodiversity, with impacts even extending into habitats such as the deep oceans which you might expect would be partially protected from it. "If octopuses radiated in this way, it's likely that other fauna did so also, so we have helped explain where some of the deep-sea biodiversity comes from."
This revelation into the global distribution and diversity of deep-sea fauna, to be reported this week in the respected scientific journal Cladistics, was made possible by intensive sampling during International Polar Year expeditions.
The findings form part of the first Census of Marine Life (CoML), set to be completed in late 2010. It aims to assess and explain the diversity, distribution and abundance of marine life in the oceans, past, present and future.
The project, which began in 2000, involves more than 2,000 scientists from 82 nations.
The findings of a study funded by the National Environment Research Council and will be reported at a conference in Spain. The World Conference on Marine Biodiversity is taking place in Valencia between 11 and 15 November.
Isolated in new habitat conditions, many different species evolved. Some octopuses lost their defensive ink sacs because there was no need for the defence mechanisms in the pitch black waters more than two kilometres below the surface.
Dr Allcock, who was assisted on the study by Dr Jan Strugnell and Dr Paulo Prodöhl from Queen's, said: "It is clear from our research that climate change can have profound effects on biodiversity, with impacts even extending into habitats such as the deep oceans which you might expect would be partially protected from it. "If octopuses radiated in this way, it's likely that other fauna did so also, so we have helped explain where some of the deep-sea biodiversity comes from."
This revelation into the global distribution and diversity of deep-sea fauna, to be reported this week in the respected scientific journal Cladistics, was made possible by intensive sampling during International Polar Year expeditions.
The findings form part of the first Census of Marine Life (CoML), set to be completed in late 2010. It aims to assess and explain the diversity, distribution and abundance of marine life in the oceans, past, present and future.
The project, which began in 2000, involves more than 2,000 scientists from 82 nations.
The findings of a study funded by the National Environment Research Council and will be reported at a conference in Spain. The World Conference on Marine Biodiversity is taking place in Valencia between 11 and 15 November.
Zooplankton Populations Plunge 70 Percent in Four Decades; Alarming Marine Biologists
NaturalNews) Numbers of zooplankton, tiny organisms that form the base of the ocean's food chain, have plummeted 70 percent since the 1960s, according to numbers collected by the British Department for Environment Food and Rural Affairs (DEFRA).The data were included without further comment in a graph on page nine of DEFRA's 2008-2009 Marine Program Plan. The nonprofit organization Buglife noticed this graph, however, and began sounding the alarm."The implications for marine productivity and fisheries are mindboggling," Buglife Scottish officer Craig Macadam said. "The biomass of the seas is (or was!) enormous. This statistic must represent a very significant reduction in the number and weight of living organisms in the UK. Yet there has been no coverage as far as I can see in any British media. I think it would be a good idea for people to be more concerned about invertebrate conservation issues."Macadam noted that the entire marine food chain rests on zooplankton. A disruption in their populations is therefore expected to affect all ocean life, from fish to sea birds to whales."Big fish feed on little fish, so when there is a big decline in the bedrock of the marine food chain it spells trouble all down it," he said.According to the DEFRA chart, zooplankton levels declined steadily starting in the 1960s and had dropped a full 50 percent by 1990. Since then, there has been another 50 percent drop, for a total of a 73 percent population decrease.Buglife Director Matt Shardlow has sent a letter to DEFRA Director of Marine and Fisheries Rodney Anderson, applauding the quality of the organization's data but calling on it to take more decisive action."The disappearance of butterflies, moths, bees, riverflies and other small animals is an environmental tragedy," Shardlow wrote. "But, despite this experience, we were profoundly shocked to read that zooplankton abundance has declined by about 73 percent since 1960 and about 50 percent since 1990."This is a biodiversity disaster of enormous proportions."
Sources for this story include: news.bbc.co.uk; news.scotsman.com.
Sources for this story include: news.bbc.co.uk; news.scotsman.com.
Oceans are teeming with undiscovered microbes
NaturalNews) While marine biologists knew that 98 percent of all life in the ocean is made up of single-celled organisms, scientists found that the diversity of the creatures may be more than 100 times greater than previously supposed.
Through the use of a DNA technique called 454 tag sequencing, researchers working on the International Census of Marine Microbes -- part of a 10-year plan which aims to catalogue marine species before the oceans are depleted -- found more than 20,000 kinds of microorganisms in a single liter of seawater. The water was expected to contain between 1,000 and 3,000 organisms.
Previously, molecular studies estimated that more than 500,000 kinds of marine microorganisms existed, but Dr. Mitchel Sogin, director of the Marine Biological Laboratory in Massachusetts, said these new results "blow away all previous estimates of bacterial diversity in the ocean."
While only 5,000 marine microbes have been named and formally described by scientists, Sogin said these new findings mean that there could be between 5 million and 10 million bacterial species in the world's oceans.
Scientists say these organisms are crucial to life on earth. "Microbes constitute the vast majority of marine biomass, and are the primary engines of the Earth's biosphere," Sogin said. "They are the oldest life forms, the primary catalysts of energy transformation, and fundamental to the biogeochemical cycles that shape our planetary atmosphere and environment."
Through the use of a DNA technique called 454 tag sequencing, researchers working on the International Census of Marine Microbes -- part of a 10-year plan which aims to catalogue marine species before the oceans are depleted -- found more than 20,000 kinds of microorganisms in a single liter of seawater. The water was expected to contain between 1,000 and 3,000 organisms.
Previously, molecular studies estimated that more than 500,000 kinds of marine microorganisms existed, but Dr. Mitchel Sogin, director of the Marine Biological Laboratory in Massachusetts, said these new results "blow away all previous estimates of bacterial diversity in the ocean."
While only 5,000 marine microbes have been named and formally described by scientists, Sogin said these new findings mean that there could be between 5 million and 10 million bacterial species in the world's oceans.
Scientists say these organisms are crucial to life on earth. "Microbes constitute the vast majority of marine biomass, and are the primary engines of the Earth's biosphere," Sogin said. "They are the oldest life forms, the primary catalysts of energy transformation, and fundamental to the biogeochemical cycles that shape our planetary atmosphere and environment."
Toxic pesticide TBT poisons worldwide marine wildlife; used widely on hulls of oil tankers
There is something picturesque about a ship bobbing up and down against a blue swell of waves and settling into a harbor to unload its cargo. Equally picturesque are the kinds of wildlife navigating underneath: Fish and shellfish scurrying about the colorful blooms of coral, piles of oysters and larger mammals, like whales and dolphins, swimming to and fro. This picture of the oceanic ecosystem is serene, almost quiet. Unfortunately, the reality of our modern marine ecosystem is far different.
For 40 years, oceanographers and fishermen have warned governments of certain marine technologies destroying the vast biota underwater. In the most recent case of environmental destruction, the culprit comes in the form of strong chemicals painted on the hulls of ships to protect from pests. Tributyltin oxide (TBT), an organotin compound, is the active ingredient in these marine paints. TBT prevents the growth of algae, barnacles and other marine organisms on the ship's hull, but, like most pesticides, these chemicals kill much more than just their targets.
TBT was first used in the 1960s as an antifouling biocide, but signs of its destructive properties didn't emerge until the 1970s. In both Europe and the United States, studies began to show rapid decimation of marine life in harbors and other high-traffic areas. The American mud-snails, dogwhelks, oysters and other mollusk populations were all in decline by the early 1970s. Shellfish were found suffering from impaired immune systems, shell deformities and a condition called imposex, in which male sexual organs appear on female mollusks.
Unfortunately, the link between these conditions and TBT was not immediately apparent. Only in the 1980s, using advanced analytical and technological instrumentation to measure TBT distribution, could scientists link these deformities directly to TBT levels. In 1986, one study of Plymouth Sound proved that increases of imposex strongly coincided with TBT applications. In 1989, studies found that the use of TBT paints on salmon-farming cages resulted in contamination of a Scottish sea loch, as well as higher incidence of imposex.
As the evidence mounted against TBT, governments slowly began to establish regulations. France, suffering huge losses in the oyster industry, was the first country to limit the use of TBT. In 1982, the French government placed controls on the application of TBT paints to vessels under 25 meters in length. (These small vessels usually spend most of their time around harbors where oyster populations could be severely effected). In 1987, the UK went one step further, banning all retail sale of TBT paint for smaller vessels. As usual, the United States was slowest to take action, introducing a similar ban in 1988.
Unfortunately, these restrictions and bans did not take into account sea-going vessels. While many of the shellfish populations partially recovered in harbors and bays, TBT dangers were by no means eliminated. The increase in commercial vessels, especially oil tankers and military vessels (both using unregulated amounts of TBT paint), has had measurable effects on marine ecosystems.
During the mid-1990s, a number of studies introduced new harms caused by TBT. This time, the effects of TBT were not limited to smaller marine life in harbors. Scientists found dangerous accumulations of butyltin in dolphins, tuna and sharks in the Mediterranean seas. A later study linked these levels to immune dysfunction. In 1997, a study linked high levels of TBT in the bottlenose dolphin to their abnormal rates of mortality reported on the U.S. Atlantic and Gulf coasts. Greenpeace also reported that TBT was been found in the tissues of cetaceans, seals, sea otters and water birds in a wide range of locations around the world.
Most startling, however, is evidence that dangerous amounts of TBT and its breakdown products accumulate in the bodies of sperm whales. This indicates that TBT may be widely dispersed in the marine environment, including the deep oceans where sperm whales normally live and feed.
In a recent study at Yale University, researchers found that TBT could cause hearing difficulties in whales and other mammals. Prestin, a protein essential to whale cochlear amplification (the amplification of sounds by tiny hairs) is severely affected by TBT levels. By hindering the mechanical activity of the outer hair cells, which boost incoming sound to the whales, TBT effectively cripples whales' auditory amplification and sensation. Because whales rely on their sensitive hearing apparatus for motor activity, damage to their ears could alter, if not annihilate, populations in some areas.
Current efforts are under way by Greenpeace and other marine environmental groups to push the government to restrict TBT use even further, if not outlaw the pesticide outright. Until then, marine populations will continue to be threatened by these toxic pesticides that remain perfectly legal to use on the hulls of oil tankers and other ships that traverse the oceans of our planet.
For 40 years, oceanographers and fishermen have warned governments of certain marine technologies destroying the vast biota underwater. In the most recent case of environmental destruction, the culprit comes in the form of strong chemicals painted on the hulls of ships to protect from pests. Tributyltin oxide (TBT), an organotin compound, is the active ingredient in these marine paints. TBT prevents the growth of algae, barnacles and other marine organisms on the ship's hull, but, like most pesticides, these chemicals kill much more than just their targets.
TBT was first used in the 1960s as an antifouling biocide, but signs of its destructive properties didn't emerge until the 1970s. In both Europe and the United States, studies began to show rapid decimation of marine life in harbors and other high-traffic areas. The American mud-snails, dogwhelks, oysters and other mollusk populations were all in decline by the early 1970s. Shellfish were found suffering from impaired immune systems, shell deformities and a condition called imposex, in which male sexual organs appear on female mollusks.
Unfortunately, the link between these conditions and TBT was not immediately apparent. Only in the 1980s, using advanced analytical and technological instrumentation to measure TBT distribution, could scientists link these deformities directly to TBT levels. In 1986, one study of Plymouth Sound proved that increases of imposex strongly coincided with TBT applications. In 1989, studies found that the use of TBT paints on salmon-farming cages resulted in contamination of a Scottish sea loch, as well as higher incidence of imposex.
As the evidence mounted against TBT, governments slowly began to establish regulations. France, suffering huge losses in the oyster industry, was the first country to limit the use of TBT. In 1982, the French government placed controls on the application of TBT paints to vessels under 25 meters in length. (These small vessels usually spend most of their time around harbors where oyster populations could be severely effected). In 1987, the UK went one step further, banning all retail sale of TBT paint for smaller vessels. As usual, the United States was slowest to take action, introducing a similar ban in 1988.
Unfortunately, these restrictions and bans did not take into account sea-going vessels. While many of the shellfish populations partially recovered in harbors and bays, TBT dangers were by no means eliminated. The increase in commercial vessels, especially oil tankers and military vessels (both using unregulated amounts of TBT paint), has had measurable effects on marine ecosystems.
During the mid-1990s, a number of studies introduced new harms caused by TBT. This time, the effects of TBT were not limited to smaller marine life in harbors. Scientists found dangerous accumulations of butyltin in dolphins, tuna and sharks in the Mediterranean seas. A later study linked these levels to immune dysfunction. In 1997, a study linked high levels of TBT in the bottlenose dolphin to their abnormal rates of mortality reported on the U.S. Atlantic and Gulf coasts. Greenpeace also reported that TBT was been found in the tissues of cetaceans, seals, sea otters and water birds in a wide range of locations around the world.
Most startling, however, is evidence that dangerous amounts of TBT and its breakdown products accumulate in the bodies of sperm whales. This indicates that TBT may be widely dispersed in the marine environment, including the deep oceans where sperm whales normally live and feed.
In a recent study at Yale University, researchers found that TBT could cause hearing difficulties in whales and other mammals. Prestin, a protein essential to whale cochlear amplification (the amplification of sounds by tiny hairs) is severely affected by TBT levels. By hindering the mechanical activity of the outer hair cells, which boost incoming sound to the whales, TBT effectively cripples whales' auditory amplification and sensation. Because whales rely on their sensitive hearing apparatus for motor activity, damage to their ears could alter, if not annihilate, populations in some areas.
Current efforts are under way by Greenpeace and other marine environmental groups to push the government to restrict TBT use even further, if not outlaw the pesticide outright. Until then, marine populations will continue to be threatened by these toxic pesticides that remain perfectly legal to use on the hulls of oil tankers and other ships that traverse the oceans of our planet.
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