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Sunday, September 30, 2018
Napier mother's plea for investigation into Ahuriri Estuary gains support
Saturday, September 29, 2018
Decapitated, limbless body found in Chiba estuary
Shearstown Estuary committee faces membership challenge
Arctic Beluga whale spotted in unlikely sighting, swimming in River Thames estuary
Genetic basis for how harmful algae blooms become toxic
Scientists have uncovered the genetic basis for the production of domoic acid, a potent neurotoxin produced by certain harmful algae blooms.
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Steelhead life cycle linked to environment, pink salmon abundance
A new study has found that steelhead trout have a remarkable life-cycle variation that responds to changes in temperature and numbers of other species of salmon.
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Middle school students learn kayaking along the Oakland Estuary
Report on estuary 'eutrofication'
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Fears for beluga whale as it swims towards London on third day in Thames
Friday, September 28, 2018
Researchers challenge our assumptions on the effects of planetary rotation
The Coriolis effect impacts global patterns and currents, and its magnitude, relative to the magnitude of inertial forces, is expressed by the Rossby number. For over 100 years, scientists have believed that the higher this number, the less likely Coriolis effect influences oceanic or atmospheric events. Recently, however, researchers found that smaller ocean disturbances with high Rossby numbers are influenced by the Coriolis effect. Their discovery challenges assumptions of theoretical oceanography and geophysical fluid dynamics.
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Beach sand ripples can be fingerprints for ancient weather conditions
When a coastal tide rolls out, it can reveal beautiful ripples in the temporarily exposed sand. These same undulating patterns can also be seen in ancient, petrified seabeds that have been exposed in various parts of the world and preserved for millions or even billions of years.
Geologists look to ancient sand ripples for clues to the environmental conditions in which they formed. For instance, the spacing between ripples is proportional to the depth of the water and the size of the waves that molded the underlying ripples.
But sand ripples aren’t always perfectly parallel, carbon-copies of each other, and can display various kinks and sworls. Can these more subtle, seemingly random deviations or defects tell us something about the conditions in which a sandy seabed formed?
The answer, according to researchers from MIT and elsewhere, is yes. In a paper published online and appearing in the Oct. 1 issue of Geology, the team reports that some common defects found in both ancient and modern seabeds are associated with certain wave conditions. In particular, their findings suggest that ripple defects resembling hourglasses, zigzags, and tuning forks were likely shaped in periods of environmental flux — for instance, during strong storms, or significant changes in tidal flows.
“The type of defect you see in ripples could tell you about how dramatic the shifts in weather conditions were at the time,” says Taylor Perron, associate professor of geology and associate head of MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “We can use these defects as fingerprints to tell not just what the average conditions were in the past, but how things were changing.”
Ripple defects in ancient sandbeds may also influence how fluids flow through sedimentary rocks, including underground reservoirs that hold water, oil and gas, or even stored carbon dioxide, according to Perron.
In addition, he says, ripple patterns in modern sand act to roughen the seabed, slowing down ocean currents near the shore. Knowing how ripples change in response to shifting waves and tides may therefore help predict coastal erosion and flooding.
Perron’s co-authors are on the paper are former MIT graduate student Kimberly Huppert ’11, PhD ’17, former undergraduate and current postdoc Abigail Koss ’12, Paul Myrow of Colorado College, and former undergraduate Andrew Wickert ’08 of the University of Minnesota.
Wrinkles preserved
The team began looking into the significance of ripple defects several years ago, when Myrow, who at the time was spending his sabbatical at MIT, showed Perron some photos that he had taken of sedimentary rocks etched with ripples and grooves. The rocks were, in fact, ancient sandbeds that were hundreds of millions of years old.
Wave-sculpted ripples form as waves travel across the surface of a body of liquid. These waves cause water beneath the surface to circle around and around, generating oscillating flows that pick up sand grains and set them down in a process that eventually carves out troughs and grooves throughout the sandbed.
But how could such delicate patterns be preserved for millions of years? Perron says that various processes could essentially set ripples in place. For instance, if the water level suddenly dropped, it could leave a sand bed’s ripples exposed to the air, drying them out and hardening them to some extent, so that they retained their patterns even as more sediment slowly layered itself on top of them over billions of years.
Similarly, if a finer sediment like mud or silt covers a sand bed, such as after a large storm, these sediments could blanket the existing ripples. As Perron explains, this would essentially “armor them, keeping the waves from eroding the ripples before more sediment buries them.” Over time, the sediments turn into rock as they are buried deep below Earth’s surface. Later, the rock overlaying the ripples can naturally erode away, exposing the preserved ripples at the surface again.
In looking through photos of sand ripples, Perron and Myrow noticed small defects resembling tuning forks, zigzags, and hourglasses, across both ancient and modern sandbeds.
“People have noticed these defects before, but we wondered, are they just random, or do they actually contain some information?” Perron says.
Paddling through waves
The researchers set out to study the various wave conditions that generate certain ripple patterns and defects. To do this, they built an acrylic wave tank measuring 60 centimers wide, 50 centimers deep, and 7 meters long. At one end of the tank, they attached a motor-driven paddle, which swished back and forth to generate waves that traveled across the tank.
At the other end of the tank, they erected an artificial sloping “beach” covered in a polymer mesh. This setup served to minimize any wave reflections: As a wave crashed onto the artificial beach, the energy dissipated within the mesh instead of splashing back and influencing oncoming waves.
The team filled the tank with a 5-centimeter-thick bed of fine sand and enough water to reach 40 centimeters in depth. For each experiment, they set the paddle to swish back and forth at a constant distance, and recorded the sand bed as ripples formed. At a certain point, they observed that the ripples — and in particular, the spacing between the ripples — reaches a stable, consistent pattern. They recorded this spacing, along with the speed and amplitude of the paddle, and then, over 32 experimental runs, either increased or decreased the paddle’s motion, causing the ripples to morph again to either a wider or narrower spacing.
Interestingly, they found that, in the process of adjusting to a new spacing, ripples formed intermediary defects resembling zigzags, hourglasses, and tuning forks, depending on the wave conditions set by the tank’s paddle.
As the researchers shortened the paddle’s back-and-forth motion, this created shorter waves, narrower ripples, and patterns that resembled hourglasses. If the paddle’s motion was shortened even further — creating faster, shorter waves — a pattern of “secondary crests,” in which existing ripples appeared to form temporary “shadow” ripples on either side, took over. When the researchers widened the paddle’s motion, generating longer waves, the ripples formed zigzag patterns as they shifted to a wider spacing.
“If you see these types of defects in nature, we argue that the seabed was undergoing some kind of change in weather conditions, tides, or something else that affected water depth or waves, probably over the course of hours or days,” Perron says. “For instance, if you’re seeing lots of secondary crests, you can tell there was a pretty big change in the waves as opposed to a smaller change, which might give you hourglasses instead.”
The researchers observed that in all scenarios, patterns resembling tuning forks cropped up, even after ripples had reached a new, stable spacing.
“These tuning forks tend to stick around for a long time,” Perron says. “If you see these in modern or ancient rock, they suggest a seabed experienced a change, but then the conditions remained steady, and the bed had a long time to adjust.”
Going forward, Perron says geologists can use the team’s results as a blueprint to connect certain ripple defects with the water conditions that may have created them, in both the modern environment and in the ancient past.
“We think these small defects can tell you a lot more about an ancient environment than just what the average size of the waves and water depth was,” Perron says. “They could tell you if it was an environment that had tides that were large enough to change ripples by this much, or if a place was experiencing periodic storms, even billions of years ago. And if we find ancient wave ripples on Mars, we’ll know how to read them.”
This research was supported, in part, by the National Science Foundation.
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Shearstown Estuary committee faces membership challenge
Arctic beluga whale 'swimming strongly' in Thames estuary
Amazon mangroves store twice as much carbon per acre as region's famous rainforest
2018 Arctic summertime sea ice minimum extent tied for sixth lowest on record
Arctic sea ice likely reached its 2018 lowest extent on Sept. 19 and again on Sept. 23, 2018. Analysis of satellite data showed that, at 1.77 million square miles (4.59 million square kilometers), 2018 effectively tied with 2008 and 2010 for the sixth lowest summertime minimum extent in the satellite record.
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Observing the development of a deep-sea greenhouse gas filter
In a long-term study, marine scientists for the first time observed the colonization of a deep-sea mud volcano after its eruption. Only slowly, rich life develops around the crater. The first settlers are tiny organisms that eat methane escaping from the volcano. Thereby, they keep this greenhouse gas from reaching the atmosphere. The present study describes how the colonization of the mud volcano proceeds and when the tiny methane-munchers get going.
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Thursday, September 27, 2018
Hawai'i land impacted by sea level rise may be double previous estimates
By including models of dynamical physical processes such as erosion and wave run-up, a team of researchers has determined that land area in Hawai'i vulnerable to future sea level rise may be double previous estimates.
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Napier mother's plea for investigation into Ahuriri Estuary gains support
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Amazon mangrove forest stores twice as much carbon per acre as region's famous rainforest
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TTFF awards for Unfinished Sentences, Hero and Mangroves
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State Panel says no mangroves, judge for yourself
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How reliable are turtles for measuring ocean trash and marine health?
A meta-analysis of fifty years worth of sea turtle research reveals some important information about ocean trash, but important data is largely missing.
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Urbanization is cutting off life support to New York City's wetlands
Using sediment cores to trace the evolution of Jamaica Bay's wetlands, a team led by researchers finds that urbanization is weakening the shoreline and starving the marshes of vital mineral sediment, causing their gradual but dramatic erosion.
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Wednesday, September 26, 2018
Work on wall along mangroves to begin in November
Hope alive for dying Uran mangroves
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Science: Concerns grow for Arctic beluga whale in Thames estuary [Report]
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Land trust opens a new loop trail in Georgetown for public use during Great Maine Outdoor Week
Concerns grow for Arctic beluga whale in Thames estuary
Microplastics found deep in sand where turtles nest
Microplastics have been found deep in the sand on beaches where sea turtles lay their eggs.
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BMC's mangrove math helps Mumbai beat Modi govt's green diktat
Technology, mangroves saving Pampanga's coastal villages
Severn Estuary Forum Set to Take Place in October
'Lost' beluga whale seen in Thames estuary – video
Tuesday, September 25, 2018
Mudlarks celebrate nine years and 25 hectares of cleared mangroves
Amazon mangrove forest stores twice as much carbon per acre as region's famous rainforest
Taking a walk around Panjim's newest attraction, the Mangrove Boardwalk
Beluga whale sighted in Thames estuary off Gravesend
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3 To Do: Estuaries Day; Stone crab blessing
Dee estuary ship being turned into zombie attraction
Retracing Antarctica's glacial past
More than 26,000 years ago, sea level was much lower than it is today partly because the ice sheets that jut out from the continent of Antarctica were enormous and covered by grounded ice -- ice that was fully attached to the seafloor. As the planet warmed, the ice sheets melted and contracted, and sea level began to rise. Researchers have discovered new information that illuminates how and when this global phenomenon occurred.
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Monday, September 24, 2018
OSU study: Amazon mangrove forests key in carbon storage
Dee estuary ship being turned into zombie attraction
Boaters Express Concerns with Nauset Estuary
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Local councillor claims every village in Shannon Estuary 'has the scourge of cocaine'
Lamu locals optimistic on end to mangrove logging ban
Sunday, September 23, 2018
Study for solution to Ennore estuary sedimentation begins
Towns and villages along Shannon Estuary awash with cocaine: Lawyer
Saturday, September 22, 2018
Activists seek mangrove control room
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Ocean acidification may reduce sea scallop fisheries
Each year, fishermen harvest more than $500 million worth of Atlantic sea scallops from the waters off the east coast of the United States. A new model, however, predicts that those fisheries may potentially be in danger.
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Friday, September 21, 2018
Bainbridge Island Land Trust acquiring waterfront property to open as nature preserve
Saturday event celebrates estuary's as lagoon languishes
Cidco killing mangroves in Navi Mumbai: Activists
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Flathead numbers terrific in the Hastings River estuary from Wauchope to the breakwalls
Thirsty Caloosahatchee Estuary Will Get More Fresh Water in the Dry Season
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Thursday, September 20, 2018
EPA Awards $2 Million to Pensacola and Perdido Bays Estuary Program
Mangrove destruction 3 days after HC order on protection
Skeletal remains found on Durban beach
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Glacial engineering could limit sea-level rise, if we get our emissions under control
Targeted engineering projects to hold off glacier melting could slow down ice-sheet collapse and limit sea-level rise, according to a new study. While an intervention similar in size to existing large civil engineering projects could only have a 30 percent chance of success, a larger project would have better odds of holding off ice-sheet collapse. But the researchers caution that reducing emissions still remains key to stopping climate change and its dramatic effects.
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Sea Shepherd Initiates Early Patrols to Safeguard Survival of Critically Endangered Vaquita Porpoise
Sea Shepherd returns to the Sea of Cortez to resume patrols protecting the critically endangered vaquita porpoise for the fifth season.
San Felipe, Mexico – August 22nd, 2018 – Sea Shepherd vessel the M/V Farley Mowat has arrived in the Upper Gulf of California in order to start Operation Milagro early this year. In previous years, the campaign has started as the totoaba fish returns from its migration to the vaquita habitat, around early November. Due to the critical state in which the vaquita porpoise species finds itself – currently the most endangered marine mammal in the world – Sea Shepherd is back earlier this season, with renewed strength to apply its proven techniques to protect the smallest porpoise in the world.
“There is work to do to ensure the vaquita survives. Sea Shepherd will start removing inactive totoaba fishing gear, also known as ghost nets and we will come across occasional active nets this early in the season,” said Sea Shepherd Director of Marine Operations and Campaigns Captain Locky Maclean. “We are also ensuring no fishing is taking place inside the protected area and preventing poaching activities by patrolling the area with our partner agencies from the Mexican Government on-board.”
The last study released showed that less than 30 vaquita were alive. Scientists have not published a new estimate in two years.
Sea Shepherd is launching Operation Milagro V, the fifth season the marine conservation group will use direct-action tactics to protect the vaquita. Milagro is the Spanish word for miracle- an appropriate name given that when the campaign began, there had been no registered vaquita sightings in two years. Many people were saying the marine mammal was already extinct. The Sea Shepherd team sighted and recorded a vaquita in early 2015. This happened as the Mexican government renewed its commitment to protect this endemic species and a partnership was born.
Since then, Sea Shepherd has developed the only proven method to date to conserve the small porpoise alive: the removal of illegal fishing gear from its habitat.
The reason for the rapid decline of the vaquita is the poaching of the totoaba fish. After the totoaba was harvested to near extinction in the mid-seventies, its fishing was banned.
Recently, however, it was discovered that the totoaba closely resembled a Chinese endemic croaker, which was critically endangered due to the demand for its swim bladder. This resulted in the start of huge amounts of illegal fishing for the totoaba in search of the swim bladder, believed to have medicinal properties. This doomed not only the fish, but even more tragically, the vaquita. The two species are of a similar size and during the totoaba spawning season, they inhabit the same exact location. This results in the death of the vaquita from the fishing nets, known as gillnets, laid to catch the totoaba.
While vaquitas used to fall prey as bycatch from fishing for shrimp and fin fish, they are now victims of the gillnets made precisely to catch a fish the same size as the vaquita.
These nets, in combination with the insatiable demand for the swim bladders in China, and the obscene value poachers can sell these bladders for – allegedly a poacher can make $2,500 per totoaba bladder, which will sell for $20,000 in Asian black markets- create a challenge the vaquita and the totoaba have never seen before.
It is therefore critical that Sea Shepherd is there to remove illegal nets and free marine wildlife.
The Mexican government has made an unprecedented effort to save their native species, dedicating a large part of the navy, the army and several other governmental institutions to solve the issue. It is no small task and Sea Shepherd has witnessed the efforts of hundreds of people working together to protect the vaquita. Sea Shepherd works in partnership with Mexico to remove the illegal fishing gear from the vaquita habitat and provide information and expertise advice to the authorities. The conservationists also provide important data to scientists and work with the community to move away from unsustainable industries and promote conservation.
Sea Shepherd has removed 808 illegal pieces of fishing gear since we began our operations. This has cost the poachers an estimated $857,779 USD just in lost fishing gear.. Sea Shepherd has saved 3069 animals, including one humpback whale, 88 critically endangered totoaba fish, one critically endangered pacific leatherback turtle and 21 sharks. Those numbers do not include the hundreds of animals saved by the removal of the nets and other fishing gear before the animals become entangled.
However, protecting the vaquita from illegal activity is no easy feat. Sea Shepherd has had a drone shot down as well as shots fired at one of the ships.
“If Sea Shepherd had not been present in the Sea of Cortez, the vaquita could be extinct by now,” said Captain Paul Watson, founder and CEO of the conservation organization. “Each year we become more efficient at the task of protecting the vaquita porpoise.”
“Last year alone, we removed more fishing gear than we had in all previous years combined. For Milagro V, we have a new vessel with better capabilities to remove nets being fitted for campaign right now.” Continued Captain Watson, “For all the people saying there is no hope for the vaquita, we disagree. We will keep fighting for her, and we will fight harder than ever. I encourage all of you to join us.”
The campaign has no end date, as the need to keep a tight watch on the vaquita porpoise becomes even more urgent. Sea Shepherd undertook what it takes to pull the species back from the brink of extinction: a presence in the Upper Gulf of California, patrolling the vaquita habitat and removing the threats that kill the porpoise.
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