Archive for the View from the Ocean Category

May 31 2019

Keep eating fish; it’s the best way to feed the world

The famous ocean explorer, Sylvia Earle, has long advocated that people stop eating fish. Recently, George Monbiot made a similar plea in The Guardian – there’s only one way to save the life in our oceans, stop eating fish – which, incidentally, would condemn several million people to starvation.

In both cases, it’s facile reasoning. The oceans may suffer from many things, but fishing isn’t the biggest. Earle and Monbiot’s sweeping pronouncements lack any thought for the consequences of rejecting fish and substituting fish protein for what? Steak? That delicious sizzler on your plate carries the most appallingly large environmental costs regarding fresh water, grain production, land use, erosion, loss of topsoil, transportation, you name it.

Luckily for our planet, not everyone eats steak. You’re vegan, you say, and your conscience is clean. An admirable choice – so long as there aren’t too many of you. For the sake of argument and numbers, let us assume that we can substitute plant protein in the form of tofu, made from soybeans, for fish protein. Soybeans need decent land; in fact it would take 2.58 times the land area of England to produce enough tofu to substitute for no longer available fish. That extra amount of decent arable land just isn’t available – unless we can persuade Brazil, Ecuador and Columbia to cut down more of the Amazon rainforest. We would also add 1.71 times the amount of greenhouse gases that it takes to catch the fish.

And, again for the sake of argument, were we to substitute beef for fish, we would need 192.43 Englands to raise all that cattle and greenhouse gases would rocket to 42.4 times what they are from fishing.

But aren’t there alternatives that we can eat with a clean conscience? It depends. First, we must accept the inescapable truth that everyone has to eat. You and I and another few billion humans right down to the single cell organisms. The second inescapable truth arises from the first but is often ignored, is that there is no free lunch. The big variable in this business of eating is deciding the appropriate price to the environment.

There are costs to each mouthful. By the time you swallow it, that mouthful has racked up a huge amount of unseen costs: production of greenhouse gases, pollution of air and waterways, soil erosion, use of freshwater, use of antibiotics, and impacts on terrestrial and aquatic biodiversity.

After extensive studies, it turns out that some fish have the lowest green house gas footprint per unit of protein.

However, it doesn’t have to be that costly. Ocean fisheries don’t cause soil erosion, don’t blow away the topsoil, don’t use any significant freshwater, don’t use antibiotics and don’t have anything to do with nutrient releases, that devastating form of pollution that causes algal blooms in freshwater and dead zones in the ocean. After extensive studies, it turns out that some fish have the lowest green house gas footprint per unit of protein. Better even than plants. Sardines, herring, mackerel, anchovies and farmed shellfish all have a lower GHG footprint than plants, and many other fisheries come close.

A ringing endorsement of fish over meat came in 2013, when Andy Sharpless, the CEO of the conservation group Oceana, pointed out that you can sustainably produce food from the sea at low environmental cost. In his book, The Perfect Protein: The Fish Lover’s Guide to Saving the Oceans, Sharpless says, “What if there was a healthy, animal sourced protein, that both the fats and the thins could enjoy without draining the life from the soil, without drying up our rivers, without polluting the air and the water, without causing our planet to warm even more, without plaguing our communities with diabetes, heart disease and cancer?” His answer was to eat fish.

There has been plenty of criticism of commercial fisheries, mostly focused on the impacts on marine ecosystems – fishing certainly reduces the abundance of fish in the ocean, and also non-target species like marine birds, mammals and turtles. But consider the alternative.

Suspend, for a minute, your image of food from the land as it appears to most of us in grocery stores or farmers’ markets – beautifully arranged vegetables, tasty bread, pretty cuts of meat as well as pre-cooked, pre-packaged, eternally preserved fast food. Then cast your minds to how and from where it comes, the raw material from a field. The land as it once was has been totally transformed by farming, replacing original habitat by clearcutting every type of existing flora and replacing it with exotic species, that would be grains, vegetables and fruit trees. Farming, be it agrobusiness or subsistence, essentially eliminates the habitat for indigenous species, and thousands of them have gone extinct because of food production, whereas no marine fish is known to have gone extinct from fishing. The ocean will remain the ocean, though of course we have to manage fish stocks well. We should press our governments to manage fisheries sustainably and minimize the environmental impacts of fishing.

Let’s give a final thought to the reality of boycotting fish and commercial fishing. The need for protein in this world is huge, and we certainly must not waste it. Fishing fleets are guided by quotas set by management and what Earle and Monbiot might boycott, will be shipped and gratefully eaten elsewhere.

Featured image: “Pile of Fish” by Oziel Gómez. Free for use via Pexels.

Ray Hilborn is a professor in the School of Aquatic and Fishery Sciences, University of Washington, specializing in natural resource management and conservation. He has co-authored several books and has published over 300 peer reviewed articles. His latest book, co-authored with Ulrike Hilborn, is Ocean Recovery: A sustainable future for global fisheries?


Original post: https://blog.oup.com/2019/05/keep-eating-fish-best-way-feed-world/

May 22 2019

Squid Research Update 2018-19

Methodological Overview


The California Wetfish Producer’s Association (CPWA) in collaboration with NOAA’s Southwest Fisheries Science Center (SWFSC) and the California Department of Fish and Wildlife has been conducting a long-term data collection program targeting California Market Squid paralarvae in Southern California since 2011, and in Monterey since 2014. Sampling sites occur at fixed and known squid spawning and aggregation sites and were selected through a collaborative process involving the squid fishing community, government managers, and independent scientists. These sites are in shallow waters, generally between 40-100 meters, over sandy substrate and often within one km from shore. Sampling effort targets the winter hatching season in southern California, sampling occurs in December, January, and February. Summer surveys are also conducted in SC and Monterey. Depending on funding availability, additional surveys are conducted in spring and autumn. To date, over 1,000 net tows have been collected during 42 survey efforts spanning nine years. Sampling is done on chartered fishing vessels and paralarvae are captured via bongo nets with a 505-micron mesh. Zooplankton volume and preservation, paralarval sorting and identification and other lab work are conducted at the SWFSC. Paralarval ageing is conducted with SWFSC personnel in an on-going project. Paralarval condition is measured by obtaining an average weight for paralarvae at a given station location, as well as measuring lengths of all individuals at a station location, or from 10 randomized individuals if >10 individuals occur at a station.

Overview – Early Winter 2018


Market squid paralarval abundance in Southern California (SC) during the winter of 2018 remained very low compared to the long-term mean, and especially compared to paralarval densities found during previous La Niña time periods (prior to 2015), indicating lingering effects from the historic 2015-16 El Niño. The 3-month mean SC paralarval density index (PDI) for the December 2018, and January and February, 2019 winter paralarval hatching season was 3.17 paralarvae per 1,000 m3 of filtered sea-water (± 19 SD). This is down from 7.43 (± 46.9) the previous hatching season (2017-18). The long-term SC winter mean PDI is 51.3 (± 342). Measurements of productivity, both zooplankton displacement volume (ZPDV) and surface chlorophyll (SCHL) declined from the previous year. ZPDV has steadily declined since the onset of the strong El Niño in 2014. Surface chlorophyll concentrations have recovered slightly from the El Niño, but are lower than last year, and still much lower than the previous period of high productivity (Fig. 1). Local sea surface temperature (SST) and the Ocean Niño Index (ONI) both saw cooling periods in 2017, but have warmed slightly during 2018 and 2019.

 

Late Winter Hatching Season, 2019


Paralarval abundance, temperature, and ocean productivity began the 2018-19 winter hatching season similarly to previous years, marked by very low abundance, warmer ocean temperatures, and reduced productivity. However, February, 2019, marked a dramatic change. A series of strong winter storms drove coastal upwelling, which cooled surface waters, increased ocean mixing, nutrient availability, zooplankton abundance, and yielded a significant increase in paralarval abundance (Table 1, Fig. 2). Zooplankton biomass and availability seems to be particularly important for market squid, likely due to the high energetic demands required by squids (O’Dor 1982). General Additive Models were used (also see Van Noord & Dorval 2017) to evaluate the importance of oceanographic variables on determining variability in paralarval density for the 2018-19 season. Sea surface temperature, ZPDV, SCHL, and four geographic variables (separating the coast from the Channel Islands and north from south at Santa Monica Bay) explained 48% of the variability in paralarval abundance. Sea surface temperature and ZPDV were particularly important in the model (Fig. 3). Greater paralarval density was associated with lower SST and moderate to high ZPDV.

 

Monterey Bay Area and Summer Sampling

The Monterey Bay Area was sampled in June, 2018 (n=15) and the paralarvae density index was 10.5 (± 7.18). This was the highest paralarvae abundance measured during the 2018-19 season. Southern California was sampled in June, 2018 and the PDI measured 0.45 (± 0.04). This was the second consecutive year that Monterey PDI values were the highest recorded in a given fishing year, indicating the population’s center of distribution may still be north following the anomalous warm water event during 2015-16, indicating that squid are seeking cooler ocean waters and greater food availability.


May 15 2019

The Keeling Curve Hits 415 PPM

Watch the new video released by Scripps Oceanography

Scripps scientists measured a record level of carbon dioxide in the atmosphere: 415 parts per million, on Sunday, May 12, 2019. This daily record, the Keeling Curve, is considered the foundation of modern climate change research. Geochemist Charles David Keeling joined Scripps in 1956 and built a manometer and other equipment to isolate the carbon dioxide in air samples. In 1958, the average carbon dioxide concentration of the first measurement was 316.16 parts per million. In 2013, the CO2 concentration surpassed 400 ppm for the first time in human history.

May 3 2019

What is the Real Cost of Protein?

With headlines published in the media like “Two-Thirds of the World’s Seafood is Over-fished” and “Science Study Predicts the Collapse of All Seafood Fisheries by 2050,” what is really the state of the ecosystems in the Earth’s oceans?

Will we deplete the ocean’s resources in the near future? or do we have time to make adaptions to ensure the vitality of fisheries?

At the Foodable.io event in Seattle, Foodable Host Yareli Quintana sat down with Dr. Ray Hilborn, professor of Fishery Sciences at the University of Washington who has been researching the topic of conservation and quantitative population dynamics of seafood for the last eight years.

Hilborn starts out by pointing out that there a two environmental challenges when it comes to seafood supply.

First, it’s the substantial fuel used to catch the fish, which generates carbon foot and then, the impact on biodiversity. As specific fish populations continue to be caught, this is changing the ecosystem of the ocean.

The seafood conservation expert also clears up a common misconception that our ocean is being depleted.

“Within the last 20 years the abundance of stock has really turned around in many places, there are certainly exceptions where that’s not true though,” says Hilborn.

But that doesn’t mean that chefs shouldn’t be concerned about what fish product that they are serving.

Each type of seafood makes a different impact on the environment. For example, Maine lobster generates a lot of energy to catch, while sardines, oysters, and mussels, on the other hand, make a really low impact.

Oyster and mussels feed themselves and most of the environmental cost comes from feed production.

Then there’s the problem of food waste, which is a challenge for restaurants, but more so, for consumers eating at home.

“One of the big issues of fish and food, in general, is waste. Globally, about 30 percent of food is wasted. In rich countries like the U.S., that’s mostly at home…So it’s important to be more careful about making sure you buy what you need and use it,” says Hilborn.

Watch the Seafood Talk Session above to learn more about the sustainability, research and management practices that are being worked on and adjusted every day in order to do right by nature and to feed the masses.


Original post: https://www.foodabletv.com/blog/what-is-the-real-cost-of-protein

Apr 9 2019

San Pedro Fishermen Help Add to Sardine Stock As­sess­ments

Video: https://spectrumnews1.com/ca/la-west/news/2019/04/08/

SAN PEDRO, CA –

Based out of San Pedro harbor, Nick Juril got his first fishing boat in 1982 and has been making a living ever since with a variety of catches including squid, mackerel, and sardines.

“I grew up with the fishery,” said Juril on the deck of his current boat, Eileen. “[It] goes back to my dad’s childhood. There’s still a handful of us left and we’re still, you know, hanging on. It would be a shame to see it go away.”

Sardine stock assessments are based primarily on acoustic trawl surveys conducted by the National Oceanic and Atmospheric Administration. According to the administration, the sardine biomass has fallen short of the 150,000 metric ton threshold needed for commercial fishing to commence. Therefore, the Fisheries Management Council has prohibited a directed sardine fishery since 2015 to allow for stocks to bounce back.

“In 2014/2015 we weren’t seeing a lot. But since the water kind of changed, the water warmed up a little bit, there’s a lot of sardines around right now,” explained Juril. “So, we’re hanging on, but not having the sardines has been really, really tough.”

Joe Ferrigno, one of Juril’s neighboring fishermen, says the loss of the sardine catch has taken as much as half of his business away.

“There was some years we fish sardines all year long,” said Ferrigno. “Now, we go farther, and we work a lot harder to try to catch a little bit of squid to make up for it.”

Besides human consumption, sardines also feed the pet food market and act as live bait in the multi-billion-dollar recreational fishing industry. They are also a food source for larger marine life, like sea lions which can be seen coming into harbor looking for fish.

Juril says the acoustic trawl surveys are flawed because they do not take near shore measurements, which is where he says fishermen are seeing stocks of sardines.

“These fisheries are managed on best available science,” said Juril, “and when the science is bad, it’s not doing anybody any good.”

Juril has been working in conjunction with the Department of Fish and Wildlife to do near shore aerial surveys. A spotter plane will take images once a school is spotted and radio back to the boat with location. The school is then scooped up with the boat’s purse nets and the yield will be measured and correlated to the images so that future estimates can be made more accurately.

“Most, or almost all almost all, of [the sardines] are always fished from 25 meters into surf line,” explained Juril.

Another neighbor, Jamie Ashley, is a bait hauler, also participating in the aerial surveys. The Pacific Fishery Management Council does allow for a few thousand tons of sardines to be harvested as live bait, but Ashley is worried that too could be shut down.

“If we can’t get sardines, we’re out of business,” Ashley said. “There’s nothing else to catch. There’s nothing else to use for bait so we’re done.”

“The corns ripe, ready to pick,” said Juril. “There’s corn all over the place and some scientists are saying, ‘No corn this year. Can’t pick it. Sorry.’ So we’re trying to do what we can do to add to the science so that they do have better information and we can get a better assessment of abundance.”

Juril will haul other catches like squid and continue the near shore surveys hoping to add to stock assessment data and end the moratorium on sardines, but scientists aren’t optimistic and worry sardine stocks will take years to recover.


Original post/video: https://spectrumnews1.com/

Apr 3 2019

Pacific sardines likely to face another shuttered season


For the past four years, fishermen who are on the ocean on a near daily basis have been reporting an increasing biomass of sardines – in a range of sizes — in nearshore waters of California. In October 2018, our collaborative CDFW/CWPA aerial survey documented more than 13,000 tons of sardine in nearshore waters along a 70-mile stretch of coast near Big Sur.

Yet the 2018 AT survey ran the length of the West Coast from Canada to Mexico and estimated only 27,547 mt in July 2019; 94 percent of the estimate was located in the Pacific Northwest, and very few sardines in California.


In light of multiple lines of evidence of recruitment and abundance excluded from this update stock assessment, we ask the Council to employ some “best available common sense,” suspend this assessment until the problems can be resolved in a new STAR panel review, and simply extend last year’s fishery management measures in the interim.




Pacific Sardines. NOAA photo.

 

Sardine fishermen on the West Coast are preparing for another year of severe restrictions after a new draft assessment from NMFS shows the the population is continuing its collapse.The new report, released on March 26, indicates a sardine population of 27,547 metric tons. Any tonnage below 50,000 metric tons is considered “overfished” by NMFS.

These numbers indicate a 98.5 percent collapse since 2006, when the population reached an estimated 1.77 million metric tons, according to NMFS data.

The assessment still must undergo review and adoption by the Pacific Fishery Management Council’s Scientific and Statistical Committee before any rules are passed to restrict this year’s season, which begins on July 1.

Last year the council voted to allow up to 7,000 metric tons of sardines to be caught by West Coast fishermen as incidental take, or bycatch.

The cause of the sardine population collapse is still being debated.

The California Wetfish Producers Association has repeatedly taken issue with NMFS’ assessment strategy. Executive Director Diane Pleschner-Steele has called Oceana-driven claims of overfishing to be “fake news.”

The organization claims that NMFS is not collecting data close enough to shore where fishermen are reporting seeing more sardines, not fewer. NMFS has acknowledged that its research vessels are unable to take stock data close to shore but have said the number of missed fish is unlikely to have a significant effect on their general findings.


 

Feb 26 2019

Environmental Impact Displacement in Fisheries & Food

A recent policy perspective paper in Conservation Letters, Lewison et al. 2019 (open access), summarized several examples of environmental impact ‘displacement,’ an important policy concept with implications for fisheries and food.

Examples of environmental impact displacement

Environmental impact displacement is when a conservation policy designed to reduce impact in one area, displaces it to another area, sometimes making the overall problem worse. Researchers cite sea turtle bycatch in swordfish fisheries as an example of displacement in fisheries: U.S. Pacific swordfish fishing was curtailed to protect sea turtles caught as bycatch. However, lower U.S. catch increased foreign swordfish demand which ended up killing more sea turtles as foreign swordfish fisheries had higher rates of bycatch.

ProPublica and the New York Times recently published a long exposé about how a U.S. policy meant to reduce carbon emissions (by increasing biofuel use) raised demand for palm oil in Southeast Asia, which actually increased emissions and jumpstarted the palm oil/biodiversity crisis (this example is also cited in Lewison et al.).

The viral Ocean Cleanup Project is another example of environmental displacement; the crowdfunded campaign was trying to remove marine debris from the great Pacific garbage patch by sweeping a giant net-like object across the ocean. However, if it had worked as intended (it broke), it would have killed many more organisms than the trash it was trying to remove from the ocean.

Environmental displacement in fisheries & food

The concept of environmental impact displacement is important to consider in fisheries management and marine conservation. The swordfish case above is a good example of displacement in individual fisheries, but there are other areas of fishery management that should consider environmental impact displacement. For example, no-take marine protected areas often increase fishing pressure outside the area being protected, nullifying the protection. In some cases, displacing fishing pressure benefits the ecosystem, but often it does not.

Zooming out in scale raises larger systemic questions about food: Consider fisheries and marine conservation as part of a broader, global system of food and ecological preservation. A legitimate argument can be made that fulfilling fishery potential and consuming more seafood is good for the planet—it provides low-carbon, low-impact protein.

As the developing world continues to acquire wealth, global demand for animal-protein will continue to rise. The more seafood that is eaten in place of cow, the better, since bovine farming is the largest driver of rainforest and biodiversity loss on the planet. Not only is seafood the lowest-impact animal protein, several kinds of seafood (e.g. farmed bivalves and wild-caught pelagics) are among the lowest impact foods of any kind.

Solutions to environmental displacement

Lewison et al. 2019 outline ways to reduce environmental impact displacement that can be applied to fisheries management and global food systems. The first step, researchers state, is explicitly considering displacement in policy design, scoping, and evaluation. Fishery managers should evaluate and understand the biological, economic, and social outcomes of proposed policies to avoid issues like accidentally increasing turtle bycatch across the world or raising fishing pressure in an area surrounding an MPA.

Other ways to avoid displacement include:

  • Think large-scale to consider all economic/biological/social relationships
  • Enact both demand-side and supply-side policies
  • International trade agreements and cooperation as a holistic approach to global conservation

Conservation groups should consider the global food system and environmental impact displacement in their advocacy; policy makers and natural resource managers should consider environmental impact displacement in their decision-making processes. Conservation will be more effective with a larger, broad approach—particularly with fisheries and food. Lewison et al. 2019 is open access and available here.


Original post: https://sustainablefisheries-uw.org/environmental-impact-displacement/

Feb 25 2019

Methane bubbling up from ocean floor provides a surprising food source for crabs, Oregon State University research shows

Oregon State University researchers have documented tanner crabs feeding at a methane seep site off British Columbia. Tanner crabs are also known as ‘snow crabs’ and sold as food. It is the first time a commercially harvested species has been known to feed at methane sites.The methane shouldn’t cause any health concerns and, in fact, it may provide an alternative energy source for seafloor-dwelling marine species. [Oregon State University]

 

Climate change will result in less ocean-borne food falling into the deep sea, scientists say. But that likely won’t be a problem for tanner crabs, according to a recent discovery by Oregon State University researchers.

The long-legged orange crabs — one of three species that crabbers harvest and sell as snow crabs — vigorously feed at methane seeps, where the gas bubbles up from the ocean floor.

“The thinking used to be that the marine food web relied almost solely on phytoplankton dropping down through the water column and fertilizing the depths,” OSU Marine Ecologist Andrew Thurber said in a statement. “Now we know that this viewpoint isn’t complete and there may be many more facets to it.”

Thurber co-authored a study that the journal Frontiers in Marine Science just published. The study details how scientists found tanner crabs in eating frenzies around a methane seep in the floor of the Pacific Ocean off British Columbia. It is one the first times that a commercially harvested seafood has been found to rely on methane seeps.

Methane seeps appear to be serving up food to seafloor-dwelling species, such as tanner crabs. This would be a hedge against climate change because nearly all models predict less food will drop into the deep sea in coming years.

“Tanner crabs likely are not the only species to get energy from methane seeps, which really haven’t been studied all that much,” Thurber said. “We used to think there were, maybe, five of them off the Pacific Northwest coast and now research is showing that there are at least 1,500 seep sites — and probably a lot more. … They are all over the world, so the idea that they may provide an energy source is quite intriguing.”

Researchers first noticed tanner crabs bunching up around methane seeps in 2012 off the British Columbia coast. The crabs sifted through sediment at the bubbling seeps. Mats of bacteria form around the seeps and the crabs munch on those.

Underwater video shows methane building up below tanner crabs hanging out at seeps and eventually flipping them. The entertaining video drew researchers to wonder why the crabs were gathered around the seeps in the first place.

OSU teamed up with scientists from the University of Victoria in Canada. The National Science Foundation in the U.S. provided support for the study.

Off the Oregon Coast, Pacific sole and black cod have been seen near methane seeps. Like the crabs, the fish are harvested.

But seafood lovers need not worry about what their food is eating. Researchers say methane seeps create nontoxic environments.

Sarah Seabook, the lead author of the study and a Ph.D. candidate at OSU, said scientists examined the guts and tissues of tanner crabs to confirm they were feeding around methane seeps.

″… We can apply these new techniques to other species and find out if the use of methane seeps as a food source is more widespread than just tanner crabs,” she said in a statement.


Original post: https://www.registerguard.com/news/20190225/methane-bubbling-up-from-ocean-floor-provides-surprising-food-source-for-crabs-oregon-state-university-research-shows

Jan 15 2019

Understanding Ocean Acidification Impacts to California’s Living Marine Resources – Ocean Science Trust

Helping the State visualize what’s at stake as oceans acidify



Now Available: http://www.oceansciencetrust.org/wp-content/uploads/2019/01/OST-OA-Impacts-Infographic-Final.pdf

A summary of the latest research on ocean acidification (OA) impacts to important species and ecosystems in California, from crab to squid, rockfish to urchins. This tool provides a tangible illustration of our current knowledge to support decision-makers in prioritizing efforts and resources to address OA impacts.

Ocean Science Trust, working closely with scientists at UC Davis Bodega Marine Lab, the Ocean Protection Council (OPC) and other partners, undertook this synthesis to help identify data gaps and prioritize where to allocate resources to further increase understanding of OA impacts to California fishery resources.

OVERVIEW: UNDERSTANDING OA RISKS TO CALIFORNIA’S LIVING MARINE RESOURCES

Ocean acidification is a complex issue that has the potential to alter marine food webs and ecosystems in California, with direct and indirect impacts to valuable marine fisheries and the aquaculture industry. Currently, state agencies working to understand the risks OA poses to coastal species, ecosystems, and human communities – an essential step to helping those at risk prepare for what’s at stake as coastal oceans continue to acidify.

VISUALIZING IMPACTS OF OA TO LIVING MARINE RESOURCES IN CALIFORNIA

As a first step towards illuminating potential natural resource management solutions, Ocean Science Trust worked closely with scientists at UC Davis Bodega Marine Lab, the Ocean Protection Council and other partners to demonstrate the potential impacts of OA on important species and ecosystems in California. We undertook a synthesis of current scientific understanding and developed communications material for use by resources managers. The species included in the synthesis represent a diverse subset of species considered as ocean climate indicators, commercially, recreationally, and/or ecologically important. This list was selected by the project team and vetted and augmented by OPC, CDFW, and aquaculture representatives.

WORKSHOP: DEFINING OCEAN ACIDIFICATION HOTSPOTS IN CALIFORNIA

Building on this assessment, Ocean Science Trust hosted a workshop in November 2018, to help managers and decision-makers incorporate OA impacts information into relevant management decisions, prioritize efforts to address these impacts, and determine where to allocate resources to further increase understanding. This workshop brought together managers, policy makers, and scientists to better understand the concept of OA hotspots, ensure it is usable by state decision-makers, and identify key gaps in data and information that inhibit action.

 

Findings from this work may also:

  • Help identify research and data gaps to understanding OA impacts to California’s fishery resources
  • Inform species selection for a modeling exercise to identify species vulnerability thresholds
  • Provide the groundwork for a quantitative OA or climate vulnerability assessment for California or the West Coast

Originally posted: http://www.oceansciencetrust.org/

Dec 28 2018

Global warming today mirrors conditions leading to Earth’s largest extinction event, UW study says

A melting iceberg floats along a fjord leading away from the edge of the Greenland ice sheet near Nuuk, Greenland, in 2011. By this century’s end, if emissions continue at their current pace, humans will have warmed the ocean about 20 percent as much as during the Permian extinction event, newly published research says. (Brennan Linsley / The Associated Press)

 

If humans continue to pump greenhouse gases at our current rate, “we have no reason to think it wouldn’t cause a similar type of extinction,” said Curtis Deutsch, a UW professor and author of the research.

More than two-thirds of life on earth died off some 252 million years ago, in the largest mass extinction event in Earth’s history.

Researchers have long suspected that volcanic eruptions triggered “the Great Dying,” as the end of the Permian geologic period is sometimes called, but exactly how so many creatures died has been something of a mystery.

Now scientists at the University of Washington and Stanford believe their models reveal how so many animals were killed, and they see frightening parallels in the path our planet is on today.

Models of the effects of volcanic greenhouse-gas releases showed the earth warming dramatically and oxygen disappearing from its oceans, leaving many marine animals unable to breathe, according to a study published Thursday in the peer-reviewed journal Science. By the time temperatures peaked, about 80 percent of the oceans’ oxygen, on average, had been depleted. Most marine animals went extinct.

The researchers tested the model’s results against fossil-record patterns from the time of the extinction and found they correlated closely. Although other factors, like ocean acidification, might have contributed some to the Permian extinction, warming and oxygen loss account for the pattern of the dying, according to the research.

By this century’s end, if emissions continue at their current pace, humans will have warmed the ocean about 20 percent as much as during the extinction event, the researchers say. By 2300, that figure could be as high as 50 percent.

“The ultimate, driving change that led to the mass extinction is the same driving change that humans are doing today, which is injecting greenhouse gases into the atmosphere,” said Justin Penn, a UW doctoral student in oceanography and the study’s lead author.

Curtis Deutsch, a UW associate professor of oceanography and an author of the research, said if society continues to pump greenhouse gases at our current rate, “we have no reason to think it wouldn’t cause a similar type of extinction.”

Massive eruptions

The earth 252 million years ago was a much different place. The continents as we know them today were still mostly one landmass, named Pangea, which looks like a chunky letter “C” on a map.

The climate, however, resembled Earth’s now, and researchers believe animals would have adapted many traits, like metabolism, that were similar to creatures today. Nearly every part of the Permian Ocean, before the extinction, was filled with sea life.

“Less than 1 percent of the Permian Ocean was a dead zone — quite similar to today’s ocean,” Deutsch said.

The series of volcanic events in Siberia that many scientists believe set off the mass extinction “makes super volcanoes look like the head of a pin,” said Seth Burgess, a geologist and volcanologist with the United States Geological Survey.

“We’re talking about enough lava erupted onto the surface and intruded into the crust to cover the area of the United States that if you looked at the U.S. from above was maybe a kilometer deep in lava,” he said.

Burgess, who has researched the Siberian Traps volcanic events but did not work on the new Science paper, said scientists believe magma rising from the earth released some extinction-causing greenhouse gases.

In addition, sills of magma still inside the earth heated massive deposits of coal, peat and carbonate minerals, among others, which vented even more carbon and methane into the atmosphere.

“That’s how you drive the Permian mass extinction, by intruding massive volumes of magma into a basin rich in carbon-bearing sediments,” he said.

The UW and Stanford research “takes the next step in figuring out why things died at the end of the Permian,” Burgess said. “It couples what we think was happening in the climate with the fossil record, and it does it elegantly.”

Animals couldn’t breathe

It took a supercomputer more than six months to simulate all the changes the volcanic eruptions are suspected of causing during the Permian period. The computer models go into remarkable detail — simulating things like clouds, ocean currents and marine plant life — in describing what temperatures and conditions were like on Earth.

The researchers knew that surface temperatures rose about 10 degrees Celsius in the tropics because of previous scientific analysis of the fossilized teeth of eel-like creatures called conodonts.

To run their model, researchers pumped volcanic greenhouse gases into their simulation to match temperature conditions at the end of the Permian period.

As temperatures climbed toward the 10-degree mark, the model’s oceans became depleted of oxygen, a trend scientists are evaluating in today’s oceans, too.

To measure how rising temperatures and less oxygen would affect animal species of the Permian period, the researchers used 61 modern creatures — crustaceans, fish, shellfish, corals and sharks. The researchers believe these animals would have similar temperature and oxygen sensitivities to Permian species because the animals adapted to live in similar climates.

Warming’s effects were twofold on the creatures, the researchers found. In warmer waters, animals need more oxygen to perform bodily functions. But warm waters can’t contain as much dissolved oxygen, which means less was available to them.

In other words, as animals’ bodies demanded more oxygen, the ocean’s supply dropped.

In their model, the researchers were able to quantify the loss of habitat as species faced increasingly challenging ocean conditions. Surface-temperature rise and oxygen loss were more substantial in areas farther from the equator. Extinction rates also increased at higher latitudes.

Animals in the tropics were already accustomed to warmer temperatures and lower oxygen levels before the volcanic eruptions shifted the climate, according to the research. As the world warmed, they could move along with their habitat.

Marine creatures that favored cold waters and high oxygen levels fared worse: They had nowhere to go.

“The high latitudes where it’s cold and oxygen is high — if you’re an organism that needs those kind of conditions to survive, those conditions completely disappear from Earth,” Deutsch said.

In modern oceans, warming and oxygen loss have also been more pronounced near the poles, researchers said, drawing another analogue between the shift in climate some 252 million years ago and what’s happening today.

“The study tells us what’s at the end of the road if we let climate [change] keep going. The further we go, the more species we’re likely to lose,” Deutsch said. “That’s frightening. The loss of species is irreversible.”


Original post: https://www.seattletimes.com/

Evan Bush: 206-464-2253 or ebush@seattletimes.com; on Twitter: @EvanBush.