Posts Tagged ocean

Jun 17 2015

New study shows Arctic Ocean rapidly becoming more corrosive to marine species

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Chukchi and Beaufort Seas could become less hospitable to shelled animals by 2030

New research by NOAA, University of Alaska, and Woods Hole Oceanographic Institution in the journal Oceanography shows that surface waters of the Chukchi and Beaufort seas could reach levels of acidity that threaten the ability of animals to build and maintain their shells by 2030, with the Bering Sea reaching this level of acidity by 2044.

“Our research shows that within 15 years, the chemistry of these waters may no longer be saturated with enough calcium carbonate for a number of animals from tiny sea snails to Alaska King crabs to construct and maintain their shells at certain times of the year,” said Jeremy Mathis, an oceanographer at NOAA’s Pacific Marine Environmental Laboratory and lead author. “This change due to ocean acidification would not only affect shell-building animals but could ripple through the marine ecosystem.”

A team of scientists led by Mathis and Jessica Cross from the University of Alaska Fairbanks collected observations on water temperature, salinity and dissolved carbon during two month-long expeditions to the Bering, Chukchi and Beaufort Seas onboard United States Coast Guard cutter Healy in 2011 and 2012.

These data were used to validate a predictive model for the region that calculates the change over time in the amount of calcium and carbonate ions dissolved in seawater, an important indicator of ocean acidification. The model suggests these levels will drop below the current range in 2025 for the Beaufort Sea, 2027 for the Chukchi Sea and 2044 for the Bering Sea. “A key advance of this study was combining the power of field observations with numerical models to better predict the future,” said Scott Doney, a coauthor of the study and a senior scientist at the Woods Hole Oceanographic Institution.

A form of calcium carbonate in the ocean, called aragonite, is used by animals to construct and maintain shells.  When calcium and carbonate ion concentrations slip below tolerable levels, aragonite shells can begin to dissolve, particularly at early life stages.  As the water chemistry slips below the present-day range, which varies by season, shell-building organisms and the fish that depend on these species for food can be affected.

This region is home to some of our nation’s most valuable commercial and subsistence fisheries. NOAA’s latest Fisheries of the United States report estimates that nearly 60 percent of U.S. commercial fisheries landings by weight are harvested in Alaska. These 5.8 billion pounds brought in $1.9 billion in wholesale values or one third of all landings by value in the U.S. in 2013.

The continental shelves of the Bering, Chukchi and Beaufort Seas are especially vulnerable to the effects of ocean acidification because the absorption of human-caused carbon dioxide emissions is not the only process contributing to acidity.  Melting glaciers, upwelling of carbon-dioxide rich deep waters, freshwater input from rivers and the fact that cold water absorbs more carbon dioxide than warmer waters exacerbates ocean acidification in this region.

“The Pacific-Arctic region, because of its vulnerability to ocean acidification, gives us an early glimpse of how the global ocean will respond to increased human-caused carbon dioxide emissions, which are being absorbed by our ocean,” said Mathis. “Increasing our observations in this area will help us develop the environmental information needed by policy makers and industry to address the growing challenges of ocean acidification.”

University of Alaska researcher Jessica Cross tests water samples during Arctic research cruise on USCG cutter Healy. (Mathis/NOAA)
 

The crew lowers sensors that measure water temperature, salinity and dissolved carbon in the Arctic Ocean. (Mathis/NOAA)


Read the original post: http://research.noaa.gov

Apr 8 2015

Oceans might take 1,000 years to recover from climate change, study suggests

la-sci-sn-oceans-climate-change-20150331-001Sea urchins disappeared for thousands of years during ancient warming periods that could be a model of future climate change, a new study shows. Here, the shells of modern sea urchins lie in a tide pool in Corona del Mar. (Glenn Koenig / Los Angeles Times)

 

Naturally occurring climate change lowered oxygen levels in the deep ocean, decimating a broad spectrum of seafloor life that took some 1,000 years to recover, according to a study that offers a potential window into the effects of modern warming.

Earth’s recovery from the last glacial period, in fact, was slower and more brutal than previously thought, according to the study, published online Monday in the journal Proceedings of the National Academy of Sciences.

Researchers deciphered that plotline from a 30-foot core of sea sediments drilled from the Santa Barbara Basin containing more than 5,000 fossils spanning nearly 13,000 years.

“The recovery does not happen on a century scale; it’s a commitment to a millennial-scale recovery,” said Sarah Moffitt, a marine ecologist at UC Davis’ Bodega Marine Laboratory and lead author of the study. “If we see dramatic oxygen loss in the deep sea in my lifetime, we will not see a recovery of that for many hundreds of years, if not thousands or more.”

Studies already have chronicled declines in dissolved oxygen in some areas of Earth’s oceans. Such hypoxic conditions can expand when ocean temperatures rise and cycles that carry oxygen to deeper areas are interrupted.

As North American glaciers retreated during a warming period 14,700 years ago, an oxygen-sensitive community of  seafloor invertebrates that included sea stars, urchins, clams and snails nearly vanished from the fossil record within about 130 years, the researchers found.

“We found incredible sensitivity across all of these taxonomic groups, across organisms that you would recognize, that you could hold in your hand, organisms that build and create ecosystems that are really fundamental to the way ecosystems function,” Moffitt said. “They were just dramatically wiped out by the abrupt loss of oxygen.”

That highly diverse community soon was replaced with a relatively narrow suite of bizarre and extreme organisms similar to those found near deep-ocean vents and methane seeps in modern oceans, Moffitt said.

Evidence of that transition was confined to such a narrow band of sediments that the turnover could have been “nearly instantaneous,” the study concluded.

Then, beginning around 13,500 years ago, the seafloor community began a slow recovery with the rise of grazers that fed on bacterial mats. Recovery eventually was driven by a fluctuation back toward glaciation during the Younger Dryas period, a cooling sometimes called the Big Freeze.

“The biological community takes 1,000 years to truly recover to the same ecological level of functioning,” Moffitt said. “And the community progresses through really interesting and bizarre states before it recovers the kind of biodiversity that was seen prior to the warming.”

That relatively brief freeze also ended abruptly around 11,700 years ago, virtually wiping out all the seafloor metazoans, the study found. They were gone within 170 years and did not appear again for more than 4,000 years, according to the study.

The climate changes chronicled in the study arose from natural cycles involving Earth’s orbit of the sun, and the oxygen declines that ensued were more extreme than those that have occurred in modern times, the study noted.

Still, the abrupt fluctuations offer a glimpse at the duration of the effects of climate change driven by human activity pumping more planet-warming gases into Earth’s atmosphere, Moffitt said.

“What this shows us is that there are major biomes on this planet that are on the table, that are on the chopping block for a future of abrupt climate warming and unchecked greenhouse gas emissions,” Moffitt said. “We as a society and civilization have to come to terms with the things that we are going to sacrifice if we do not reduce our greenhouse gas footprint.”


Read original post: http://www.latimes.com

Sep 7 2014

El Niño forecast is up in the air for Southern California

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With the summer winding down, weather officials say the winter forecast is wide open.

While a mild-to-moderate El Niño weather pattern is widely expected to develop in the fall, forecast models have “projected many different outcomes,” said Eric Boldt, a meteorologist with the National Weather Service.

“The odds of drier than normal winter are just as high as a wetter than normal winter,” he said in a video released Tuesday.

Last month, climatologists downgraded the chance of El Niño forming this fall from 80% to 65%. But the latest three-month outlook for January to March shows a potential for above-normal precipitation in Southwest California, Boldt said.

Forecasters are in El Niño watch mode, noting that sea temperatures along the equatorial Pacific have warmed, a possible signal that the storm-producing weather system is strengthening, Boldt said.

In the last four weeks, sea surface temperatures were also above average along the eastern equatorial Pacific Ocean.

El Niño winters in Southwest California have been historically wet, which would be a welcome reprieve for a region parched by a prolonged drought.

Nearly 60% of the state is experiencing “exceptional” drought conditions, the harshest on a five-level scale as measured by U.S. Drought Monitor.

For breaking news in Los Angeles and throughout California, follow @VeronicaRochaLA. She can be reached at veronica.rocha@latimes.com.

Copyright © 2014, Los Angeles Times


View the original post here.

Jul 27 2014

What seafood guzzles the most gas?

CWPA note: California’s wetfish fisheries are the most efficient in the world (2,000 pounds of protein for 6 gallons of diesel).

Please download ‘Fishing Green‘ from our website californiawetfish.org — (under the Fast Facts link).

 

Fill 'er up. Trawling for tiger prawns can burn an enormous amount of fuel, but better management of the stock has increased efficiency.

© Australian Fisheries Management Authority

Fill ‘er up. Trawling for tiger prawns can burn an enormous amount of fuel, but better management of the stock has increased efficiency.

Most of us don’t think about fuel when we eat seafood. But diesel is the single largest expense for the fishing industry and its biggest source of greenhouse gases. Not all fish have the same carbon finprint, however, and a new study reveals which ones take the most fuel to catch.

Robert Parker, a Ph.D. student at the University of Tasmania, Hobart, in Australia, and Peter Tyedmers, an ecological economist at Dalhousie University in Halifax, Canada, analyzed more than 1600 records of fuel use by fishing fleets worldwide. They added up the fuel required to catch and bring various types of fish and seafood to port, which they reported online this month in Fish and Fisheries.

Parker and Tyedmers didn’t consider the energy required to process the catch and transport it to consumers, but other studies indicate this is usually a smaller fraction. Nor did they look at environmental impacts that depend on the type of fishing gear, such as habitat destruction and the accidental killing of turtles, birds, and dolphins.

Here’s the upshot, ranked by average amount of fuel required to land a metric ton:

7. Sardines: 71 liters

Abundant forage fish like these tend to school close to shore, and it’s fairly quick work to surround them with an enormous net. Icelandic herring and Peruvian anchovies are the least fuel-intensive industrial fisheries known, caught with just 8 liters of fuel per ton of fish.

6. Skipjack tuna: 434 liters

Like forage fish, these tuna and other kinds of open-water finfish are caught en masse in a net called a purse seine. But the vessels must travel farther to find the fish, hence the bigger gas bill.

5. Scallops: 525 liters

Bottom-dwelling mollusks are scooped up with heavy steel dredges.

4. North American salmon: 886 liters

Salmon are typically caught in rivers and bays with gill nets or purse seines. Catching them by hook and line takes more fuel.

3. Pacific albacore: 1612 liters

Trolling takes more fuel than using nets does. After dropping long lines with baited hooks, vessels race to keep up with the speedy predators.

2. Sole: 2827 liters

To catch flatfish, a boat drags a heavy metal beam across the sea floor with a net attached. This is hard work for the engines.

1. Shrimp and lobster: 2923 liters

Although it takes just 783 liters of fuel to fetch a ton of Maine lobsters from traps, Asian tiger prawns (a type of shrimp) from Australia required 7000 liters of fuel per ton in 2010, and Norway lobster from the North Sea has taken as much as 17,000. These two species are small and relatively scarce, so boats must pull a fine net for long distances.

How does wild seafood compare with other kinds of animal protein? The median fuel use in the fisheries is 639 liters per ton. In terms of climate impact, that’s equivalent to a bit more than 2 kilograms of carbon dioxide emitted for each kilogram of seafood landed. Chicken and farmed salmon and trout are roughly the same, but beef is significantly higher at 10 kg of carbon dioxide per kg of live animal. “If you’re looking at having a green diet, you want to transition away from beef,” Parker says.

One implication of the study is that a lot of fuel has been wasted due to mismanagement of fisheries. In past decades, government subsidies led to bigger and more powerful boats that could catch even more fish. But as stocks became depleted, crews had to fish longer and farther away from shore. Fuel use appears to have declined over the past decade. The most important factors in this decrease, Tyedmers and Parker say, are the recovery of fish stocks and the reduction in the size of fleets; the remaining vessels don’t have to travel as far.

Tyedmers and Parker are working with the Monterey Bay Aquarium in California to determine if fuel use can be incorporated into the Seafood Watch program, which evaluates the sustainability of fisheries. But people probably shouldn’t get too hung up on the fuel numbers, says Christopher Costello, an environmental economist at the University of California, Santa Barbara, who wasn’t connected to the study. Fish consumption is a tiny part of the carbon footprint of most Americans—probably less than a half a percent of the carbon output of driving, he estimates. Still, Parker says that changing your diet, unlike changing your means of transportation, can be a relatively easy thing to do.


 

Read the original post here.

Jul 15 2014

More Big Whales in Ocean Could Mean More Fish, Scientists Find

New study reveals how scientists and fisheries managers underestimated the massive mammals.

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The return of large whales—such as sperm (pictured), blue, right, and gray—could help ocean fish populations recover.

Photograph by Stephen Frink, Corbis

Brian Clark Howard
National Geographic
Published July 10, 2014

Scientists and fisheries managers have long underestimated the valuable role large whales play in healthy ocean ecosystems, a new study suggests. And, scientists add, those commercial fishermen who complain that whales steal fish from their nets have it wrong.

An increase in the number of large whales—like blue, sperm, right, and gray—around the world could lead to a healthier ocean and more fish, a team of scientists report in a review study published this month in the journal Frontiers in Ecology and the Environment.

The underestimation occurred because “when oceanographic studies were started, large whales were largely absent from the ecosystem—because we had killed most of them,” says the study’s lead author, Joe Roman, a biologist at the University of Vermont in Burlington.

Large whales were heavily hunted until the 1970s. At that point an estimated 66 to 90 percent of the animals had been removed from ocean waters.

But since then, great whales have been slowly recovering. There are now more than a million sperm whales, and tens of thousands of gray whales.

Yet blue whales—the largest animal ever known to have lived on the planet—have been slower to rebound. In fact, they remain at about one percent of their historic range in the Southern Hemisphere. Roman says scientists think their absence may have altered the ecosystem in a way that made it harder for all life to survive there.

In recent years, as whale numbers have increased and technology has advanced—especially the ability to tag and track seafaring animals—we’ve begun to gain a better understanding of how important cetaceans are, says Roman.

“Whale Pumps and Conveyor Belts”

The scientists report that when whales feed, often at great depths, and then return to the surface to breathe, they mix up the water column. That spreads nutrients and microorganisms through different marine zones, which can lead to feeding bonanzas for other creatures. And the materials in whale urine and excrement, especially iron and nitrogen, serve as effective fertilizers for plankton.

Many great whales migrate long distances to mate, during which time they bring those nutrients with them. When they breed in far latitudes, they make important nutrient contributions to waters that are often poor in resources. Even their placentas can be rich sources of feedstocks for other organisms, says Roman, who calls whale migration a “conveyor belt” of nutrients around the ocean.

Whale deaths can be helpful too. When one of the massive mammals dies, its body sinks to the sea bottom, where it nourishes unique ecosystems of scavengers, from hagfishes to crabs to worms. Dozens of those scavenger species are found nowhere else, says Roman.

“Because [humans] took out so many whales, there were probably extinctions in the deep sea before we knew those [scavenger] species existed,” says Roman, who adds that he’s working on a new study to estimate how many of those scavenger species were lost.

Maddalena Bearzi, a marine biologist and president of the California-based Ocean Conservation Society who was not affiliated with the study, calls the paper “a great and interesting piece” that could help us better understand the role marine mammals play in the ocean ecosystem.

Fishers vs. Whales

For decades some commercial fishermen have complained that whales eat the fish that they’re trying to catch. Japan’s government has been particularly vocal, going as far as to say that whaling is necessary because “whales are threatening our fisheries.” (See “Japan’s Commercial Whaling Efforts Should Resume, Says Prime Minister.”)

Masayuki Komatsu, one of Japan’s international whaling negotiators, famously told the Australian Broadcasting Corporation in 2001 that “there are too many” minke whales, calling them “the cockroach of the ocean.”

Roman disagrees.

“It’s far more complicated than that,” he says, referring to the whale pump and the conveyor belt. “Our new review points to several studies that show you have more fish in an ecosystem by having these large predators there.”

The next step, he says, is to conduct more field studies on those processes. That could help scientists better understand exactly how plankton and other organisms respond to the presence of whales.


 

Read original post and view the videos at: news.nationalgeographic.com

May 17 2014

Intense El Nino seen likely to be developing this fall

Seafood News

SEAFOODNEWS.COM [SCOM] – May 15, 2014 –

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New NASA satellite images seem to show that El Niño conditions seem to be developing in the equatorial Pacific Ocean, data from satellites and ocean sensors indicate.  The ocean temperature profile in May 2014 appears very similar to that of 1997, when an intense El Nino cycle formed.

A natural climate cycle that brings abnormally toasty temperatures to the Pacific Ocean, El Niño occurs when winds pile up warm water in the eastern part of the equatorial Pacific, triggering changes in atmospheric circulation that affects rainfall and storm patterns around the world.

Sea-surface height can reveal if such heat is being stored in particular regions of the ocean, since water expands as it warms. Above-normal sea-surface height in the equatorial Pacific Ocean, in turn, can suggest an El Niño is developing, according to NASA’s Earth Observatory.

That’s what is showing up right now, as satellite images taken from the Ocean Surface Topography Mission/Jason 2 satellite reveal sea-surface height, averaged over a 10-day period centered on May 3, is above normal. A similar anomaly showed up during May 1997 — which coincided with one of the strongest El Niños ever experienced. That year North America saw one of its warmest and wettest winters on record; Central and South America saw immense rainstorms and flooding; and Indonesia along with parts of Asia endured severe droughts, the Earth Observatory noted.

“What we are now seeing in the tropical Pacific Ocean looks similar to conditions in early 1997,” said Eric Lindstrom, oceanography program manager at NASA headquarters, in an Earth Observatory statement. “If this continues, we could be looking at a major El Niño this fall. But there are no guarantees.”

A network of sensors in the Pacific Ocean reveals a deep pool of warm water shifting eastward, supporting the satellite data, according to the Earth Observatory.
Model predictions issued on May 8 by the National Weather Service Climate Prediction Center forecast that the chances of an El Niño developing during the summer are more than 65 percent. “These atmospheric and oceanic conditions collectively indicate a continued evolution toward El Niño,” the alert read.

This event may be just the beginning of more intense El Niños to come, according to research detailed Jan. 19 in the journal Nature Climate Change. That study suggested the most powerful El Niño events may occur every 10 years rather than every 20 years, due to rising sea-surface temperatures overall in the eastern Pacific Ocean.


Republished with permission of SeafoodNews.com

View the original article here.

May 3 2014

Vital part of food web dissolving

seachange

Scientists have documented that souring seas caused by CO2 emissions are dissolving pteropods, a key marine food source. The research raises questions about what other sea life might be affected.

It didn’t take long for researchers examining the tiny sea snails to see something amiss.

The surface of some of their thin outer shells looked as if they had been etched by a solvent. Others were deeply pitted and pocked.

View the article here. — SeattleTimes.com
Story by
CRAIG WELCH

Apr 5 2014

Giant squid escapes icy tomb

27 March, 2014 3:06PM AEST By Lucinda Kent

 

One of the ocean’s monsters is being revealed to the public for the first time in the Queensland Museum’s latest exhibition.

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The giant squid has been thawed and preserved for public display at the Queensland Museum for the first time. (ABC Multiplatform:Lucinda Kent)

 
A giant squid that was found frozen in a block of ice has been thawed and meticulously preserved by scientists for display in the Deep Oceans exhibition.

See more photos at the 612 ABC Brisbane Facebook page.

Mollusc expert Darryl Potter says the squid on display may seem large at around seven metres long, but the species can grow all the way up to 13 metres in length including their ‘club tentacles’ used for killing prey.

Giant squid live in some of the deepest parts of the ocean and were thought to be mythological creatures until around 100 years ago, but the first sighting of a live giant squid in the ocean was in September 2004.

“They were spotted by mariners in early days and that lead to the tales of monsters from the deep,” Mr Potter said.

“That of course led to all your science fiction movies with grossly distorted facts about the size of these things and what they ate.”

Mr Potter says the giant squid on display in the Deep Oceans exhibition, is known as Cal, short for calamari, is one of the best preserved specimens in the world.

Breaking the ice

Cal the squid had previously been on display at Underwater World on the Sunshine Coast, where it was kept frozen in the block of ice it was found in, which kept the creature intact before museum scientists used professional preservation techniques.

“We brought it back to the museum here and it took about three days of chipping through the ice very carefully because you didn’t want to damage any of the appendages,” he said.

“Not only just chipping through it but there’s a lot of ice that was inside it that had to thaw, it sat around for about a week completely thawing.”

Museum workers had to don protective ‘spacesuits’ while they applied chemicals that keep the animal’s skin, tentacles, and head permanently fixed.

The squid has been kept in the museum laboratories for the past 5 years and can be seen for the first time out of the ice at the Deep Oceans exhibit at the Queensland Museum from 28 March to 6 October 2014.

Mar 7 2014

Assessing the Vulnerability of Fish Stocks in a Changing Climate

NOAA
What is the Fish Stock Climate Vulnerability Assessment?
NOAA Fisheries, in collaboration with the NOAA Office of Oceanic and Atmospheric Research – “Earth System Research Laboratory, is finalizing a methodology to rapidly assess the vulnerability of U.S. marine stocks to climate change. The methodology uses existing information on climate and ocean conditions, species distributions, and species life history characteristics to estimate the relative vulnerability of fish stocks to potential changes in climate.

Climate change is already impacting fishery resources and the communities that depend on them.  Scientists are linking changes in ocean temperatures to shifting fish stock distributions and abundances in many marine ecosystems, and these impacts are expected to increase in the future.

To prepare for and respond to current and future changes in climate and oceans, fisheries managers and scientists need tools to identify what fishery resources may be most vulnerable in a changing climate and why certain fish stocks are vulnerable.  By providing this information, the methodology will be able to help fisheries managers and scientists identify ways to reduce risks and impacts to fisheries resources and the people that depend on them.  These kinds of climate change vulnerability assessments are increasingly being used to help assess risks to terrestrial and freshwater natural resources and man-made structures such as buildings and bridges.

Read the full article here.

Feb 18 2014

Global Fish biomass may be 10 times higher than thought says acoustic survey

Seafood News

According to a paper produced by Carlos Duarte for the Spanish National Research Council, fish biomass in the ocean is 10 times higher than estimated.  The 6 million euro project consisted of a series of acoustic transects that detected mesopelagic species like lantern fish.  These fish are generally found in the open ocean between 200 and 1000 meters, and the rise to the shallower depth at night, and retreat deeper during the day.  They also detect nets and can flee from trawls.

Mesopelagic fishes, are fish such as lantern fishes (Myctophidae) and cyclothonids (Gonostomatidae), who live in the twilight zone of the ocean, between 200 and 1,000 meters deep. They are the most numerous vertebrates of the biosphere, but also the great unknowns of the open ocean, since there are gaps in the knowledge of their biology, ecology, adaptation and global biomass.

With a stock estimated at 1,000 million tons so far, mesopelagic fish dominate the total biomass of fish in the ocean.

However, a team of researchers with the participation of the Spanish National Research Council (CSIC) has found that their abundance could be at least 10 times higher. The results, published in Nature Communications journal, are based on the acoustic observations conducted during the circumnavigation of the Malaspina Expedition.

During the 32,000 nautical miles traveled during the circumnavigation, the researchers of the Malaspina Expedition (a project led by CSIC researcher Carlos Duarte) took measurements between 40°N and 40°S, from 200 to 1,000 meters deep, during the day.

Duarte states: “Malaspina has provided us the unique opportunity to assess the stock of mesopelagic fish in the ocean. Until now we only had the data provided by trawling. It has recently been discovered that these fishes are able to detect the nets and run, which turns trawling into a biased tool when it comes to count its biomass”.

Read the full article here.

Fish Biomass