Archive for the Research Category

Nov 8 2018

Quantifying sensitivity and adaptive capacity of shellfish in the Northern California Current Ecosystem to increasing prevalence of ocean acidification and hypoxia

The severity of carbonate chemistry changes from ocean acidification is predicted to increase greatly in the coming decades, with serious consequences for marine species-­ especially those reliant on calcium carbonate for structure and function (Fabry et al. 2008). The Northern California Current Ecosystem off the coast of US West Coast experiences seasonal variations in upwelling and downwelling patterns creating natural episodes of hypoxia and calcite/aragonite undersaturation, exacerbating global trends of increasing ocean acidification and hypoxia (OAH) (Chan et al. 2008) (Gruber et al. 2012). The goal of these experiments was to identify thresholds of tolerance and attempt to quantify a point at which variance in responses to stress collapses. This study focuses on two species: Cancer magister (Dungeness crab) and Haliotis rufescens (red abalone). These species were selected for this study based on their economic and ecological value, as well as their taxonomic differences. Respirometry was used as a proxy for metabolic activity at four different scenarios mimicking preindustrial, upwelling, contemporary upwelling, and distant future conditions by manipulating dissolved oxygen and inorganic carbon (DIC) concentrations. Both species showed a decrease in mean respiration rate as OAH stressors increase, including an effect in contemporary upwelling conditions. These results suggest that current exposure to ocean acidification (OA) and hypoxia do not confer resilience to these stressors for either taxa. In teasing apart the effects of OAH as multiple stressors, it was found that Dungeness crab response was more strongly driven by concentration of dissolved oxygen, while red abalone data suggested a strong interactive effect between OA and hypoxia. Not only did these two different taxa exhibit different responses to a multiple stressors, but the fact that the Dungeness crab were secondarily impacted by acidification could suggest that current management concerns may need to be focus more strongly on deoxygenation.

Gossner H. M., 2018. Quantifying sensitivity and adaptive capacity of shellfish in the northern California current ecosystem to increasing prevalence of ocean acidification and hypoxia. MSc thesis, Oregon State University, 104 p. Thesis.


Original post: https://news-oceanacidification-icc.org/

Nov 8 2018

Alterations to seabed raise fears for future

The ocean floor as we know it is dissolving rapidly as a result of human activity.

Normally the deep sea bottom is a chalky white. It’s composed, to a large extent, of the mineral calcite (CaCO3) formed from the skeletons and shells of many planktonic organisms and corals. The seafloor plays a crucial role in controlling the degree of ocean acidification. The dissolution of calcite neutralizes the acidity of the CO2, and in the process prevents seawater from becoming too acidic. But these days, at least in certain hotspots such as the Northern Atlantic and the southern Oceans, the ocean’s chalky bed is becoming more of a murky brown. As a result of human activities the level of CO2 in the water is so high, and the water is so acidic, that the calcite is simply being dissolved.

The McGill-led research team who published their results this week in a study in PNAS believe that what they are seeing today is only a foretaste of the way that the ocean floor will most likely be affected in future.

Long-lasting repercussions

“Because it takes decades or even centuries for CO2 to drop down to the bottom of the ocean, almost all the CO2 created through human activity is still at the surface. But in the future, it will invade the deep-ocean, spread above the ocean floor and cause even more calcite particles at the seafloor to dissolve,” says lead author Olivier Sulpis who is working on his PhD in McGill’s Dept. of Earth and Planetary Sciences. “The rate at which CO2 is currently being emitted into the atmosphere is exceptionally high in Earth’s history, faster than at any period since at least the extinction of the dinosaurs. And at a much faster rate than the natural mechanisms in the ocean can deal with, so it raises worries about the levels of ocean acidification in future.”

In future work, the researchers plan to look at how this deep ocean bed dissolution is likely to evolve over the coming centuries, under various potential future CO2 emission scenarios. They believe that it is critical for scientists and policy makers to develop accurate estimates of how marine ecosystems will be affected, over the long-term, by acidification caused by humans.

How the work was done

Because it is difficult and expensive to obtain measurements in the deep-sea, the researchers created a set of seafloor-like microenvironments in the laboratory, reproducing abyssal bottom currents, seawater temperature and chemistry as well as sediment compositions. These experiments helped them to understand what controls the dissolution of calcite in marine sediments and allowed them to quantify precisely its dissolution rate as a function of various environmental variables. By comparing pre-industrial and modern seafloor dissolution rates, they were able to extract the anthropogenic fraction of the total dissolution rates.

The speed estimates for ocean-bottom currents came from a high-resolution ocean model developed by University of Michigan physical oceanographer Brian Arbic and a former postdoctoral fellow in his laboratory, David Trossman, who is now a research associate at the University of Texas-Austin.

“When David and I developed these simulations, applications to the dissolution of geological material at the bottom of the oceans were far from our minds. It just goes to show you that scientific research can sometimes take unexpected detours and pay unexpected dividends,” said Arbic, an associate professor in the University of Michigan Department of Earth and Environmental Sciences.

Trossman adds: “Just as climate change isn’t just about polar bears, ocean acidification isn’t just about coral reefs. Our study shows that the effects of human activities have become evident all the way down to the seafloor in many regions, and the resulting increased acidification in these regions may impact our ability to understand Earth’s climate history.”

“This study shows that human activities are dissolving the geological record at the bottom of the ocean,” says Arbic. “This is important because the geological record provides evidence for natural and anthropogenic changes.”

McGill University (via SienceDaily), 29 October 2018. Article.


Originally posted: https://news-oceanacidification-icc.org/

Nov 2 2018

Startling new research finds large buildup of heat in the oceans, suggesting a faster rate of global warming

The findings mean the world might have less time to curb carbon emissions.

 

A post-sunset swimmer at Moonlight Beach in Encinitas, Calif., this month. (Mike Blake/Reuters) (MIKE BLAKE/Reuters)

The world’s oceans have been soaking up far more excess heat in recent decades than scientists realized, suggesting that Earth could be set to warm even faster than predicted in the years ahead, according to new research published Wednesday.

Over the past quarter-century, Earth’s oceans have retained 60 percent more heat each year than scientists previously had thought, said Laure Resplandy, a geoscientist at Princeton University who led the startling study published Wednesday in the journal Nature. The difference represents an enormous amount of additional energy, originating from the sun and trapped by Earth’s atmosphere — the yearly amount representing more than eight times the world’s annual energy consumption.

In the scientific realm, the new findings help resolve long-running doubts about the rate of the warming of the oceans before 2007, when reliable measurements from devices called “Argo floats” were put to use worldwide. Before that, differing types of temperature records — and an overall lack of them — contributed to murkiness about how quickly the oceans were heating up.

The higher-than-expected amount of heat in the oceans means more heat is being retained within Earth’s climate system each year, rather than escaping into space. In essence, more heat in the oceans signals that global warming is more advanced than scientists thought.

“We thought that we got away with not a lot of warming in both the ocean and the atmosphere for the amount of CO2 that we emitted,” said Resplandy, who published the work with experts from the Scripps Institution of Oceanography and several other institutions in the United States, China, France and Germany. “But we were wrong. The planet warmed more than we thought. It was hidden from us just because we didn’t sample it right. But it was there. It was in the ocean already.”

The United Nations panel on climate issued a report warning of unprecedented temperature rise between 2030 and 2052 if global warming continues.

Wednesday’s study also could have important policy implications. If ocean temperatures are rising more rapidly than previously calculated, that could leave nations even less time to dramatically cut the world’s emissions of carbon dioxide, in the hope of limiting global warming to the ambitious goal of 1.5 degrees Celsius (2.7 degrees Fahrenheit) above preindustrial levels by the end of this century.

The world already has warmed one degree Celsius (1.8 degrees Fahrenheit) since the late 19th century. Scientists backed by the United Nations reported this month that with warming projected to steadily increase, the world faces a daunting challenge in trying to limit that warming to only another half-degree Celsius. The group found that it would take “unprecedented” action by leaders across the globe over the coming decade to even have a shot at that goal.

Meanwhile, the Trump administration has continued to roll back regulations aimed at reducing carbon emissions from vehicles, coal plants and other sources and has said it intends to withdraw from the Paris climate accord. In one instance, the administration relied on an assumption that the planet will warm a disastrous seven degrees Fahrenheit, or about four degrees Celsius, by the end of the century in arguing that a proposal to ease vehicle fuel-efficiency standards would have only minor climate impacts.

The new research underscores the potential consequences of global inaction. Rapidly warming oceans mean that seas will rise faster and that more heat will be delivered to critical locations that already are facing the effects of a warming climate, such as coral reefs in the tropics and the ice sheets of Greenland and Antarctica.

“In case the larger estimate of ocean heat uptake turns out to be true, adaptation to — and mitigation of — our changing climate would become more urgent,” said Pieter Tans, who is the leader of the Carbon Cycle Greenhouse Gases Group at the National Oceanic and Atmospheric Administration and was not involved in the study.

The oceans absorb more than 90 percent of the excess energy trapped within the world’s atmosphere.

The new research does not measure the ocean’s temperature directly. Rather, it measures the volume of gases, specifically oxygen and carbon dioxide, that have escaped the ocean in recent decades and headed into the atmosphere as it heats up. The method offered scientists a reliable indicator of ocean temperature change because it reflects a fundamental behavior of a liquid when heated.

“When the ocean warms, it loses some gas to the atmosphere,” Resplandy said. “That’s an analogy that I make all the time: If you leave your Coke in the sun, it will lose the gas.”

This approach allowed researchers to recheck the contested history of ocean temperatures in a different and novel way. In doing so, they came up with a higher number for how much warming the oceans have experienced over time.

“I feel like this is a triumph of Earth-system science. That we could get confirmation from atmospheric gases of ocean heat content is extraordinary,” said Joellen Russell, a professor and oceanographer at the University of Arizona. “You’ve got the A team here on this paper.”

But Russell said the findings are hardly as uplifting.

The report “does have implications for climate sensitivity, meaning, how warm does a certain amount of CO2 make us?” Russell said, adding that the world could have a smaller “carbon budget” than once thought. That budget refers to the amount of carbon dioxide humans can emit while still being able to keep warming below dangerous levels.

The scientists calculated that because of the increased heat already stored in the ocean, the maximum emissions that the world can produce while still avoiding a warming of two degrees Celsius (3.6 Fahrenheit) would have to be reduced by 25 percent. That represents a very significant shrinkage of an already very narrow carbon “budget.”

The U.N. panel of climate scientists said recently that global carbon emissions must be cut in half by 2030 if the world hopes to remain beneath 1.5 Celsius of warming. But Resplandy said that the evidence of faster-warming oceans “shifts the probability, making it harder to stay below the 1.5-degree temperature target.”

Understanding what is happening with Earth’s oceans is critical, because they, far more than the atmosphere, are the mirror of ongoing climate change.

According to a major climate report released last year by the U.S. government, the world’s oceans have absorbed about 93 percent of the excess heat caused by greenhouse gases since the mid-20th century. Scientists have found that ocean heat has increased at all depths since the 1960s, while surface waters also have warmed. The federal climate report projected a global increase in average sea surface temperatures of as much as nearly five degrees Fahrenheit by 2100 if emissions continue unabated, with even higher levels of warming in some U.S. coastal regions.

The world’s oceans also absorb more than a quarter of the carbon dioxide emitted annually from human activities — an effect making them more acidic and threatening fragile ecosystems, federal researchers say. “The rate of acidification is unparalleled in at least the past 66 million years,” the government climate report stated.

Paul Durack, a research scientist at the Lawrence Livermore National Laboratory in California, said Wednesday’s study offers “a really interesting new insight” and is “quite alarming.”

The warming found in the study is “more than twice the rates of long-term warming estimates from the 1960s and ’70s to the present,” Durack said, adding that if these rates are validated by further studies, “it means the rate of warming and the sensitivity of the Earth’s system to greenhouse gases is at the upper end.” He said that if scientists have underestimated the amount of heat taken up by the oceans, “it will mean we need to go back to the drawing board” on the aggressiveness of mitigation actions the world needs to take promptly to limit future warming.

Beyond the long-term implications of warmer oceans, Russell added that in the short term, even small changes in ocean temperatures can affect weather in specific places. For instance, scientists have said warmer oceans off the coast of New England have contributed to more-intense winter storms.

“We’re only just now discovering how important ocean warming is to our daily lives, to our daily weather,” she said.


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

Aug 24 2018

Southern California Coast Emerges as a Toxic Algae Hot Spot

— Posted with permission of SEAFOODNEWS.COM. Please do not republish without their permission. —

Copyright © 2018 Seafoodnews.com

Seafood News


 

SEAFOODNEWS.COM [University of Southern California] August 23, 2018

A new, comprehensive survey led by USC scientists shows the Southern California coast harbors some of the world’s highest concentrations of an algal toxin dangerous to wildlife and people who eat local seafood.

Episodic outbreaks of algae-produced toxins make headlines every few years when stricken marine animals wash ashore between Santa Barbara and San Diego. The USC research is the most thoroughgoing assessment yet and reveals the growing scale of the problem over the last 15 years. The researchers say their findings can help protect human health and environment by improving methods to monitor and manage harmful algal blooms.

The findings are a “smoking gun” linking domoic acid produced by some types of algae to deaths of marine birds and mammals, according to David Caron, a biologist at the USC Dornsife College of Letters, Arts and Sciences, and postdoctoral researcher Jayme Smith, the study’s main authors.

“We are seeing an increase in harmful algal blooms and an increase in severity,” Caron said. “The Southern California coast really is a hot spot and our study also shows that the concentrations of particulate domoic acid measured in the region are some of the highest – if not the highest – ever reported.”

The findings appear in Harmful Algae.

Domoic acid is produced by microscopic Pseudo-nitzschia, needle-like diatoms in the water; half of the species in its genus can produce the neurotoxin. It can stain the ocean, a condition generically called “red tide,” although this particular toxin is brown. The substance accumulates in shellfish and moves up the food chain, where it attacks the nervous system of fish, birds, seals and sea lions. It can cause amnesic shellfish poisoning (ASP) in people. ASP symptoms include rapid onset of headaches, abdominal pain, cramping, nausea or vomiting; severe symptoms include permanent short-term memory loss, seizures, coma or shock in 48 hours. Although human fatalities are rare, the California Department of Public Health monitors coastal waters and shellfish for the toxin.

The research encompasses the years 2003 to 2017 between Santa Barbara and the Mexico border, and includes new samples and tests collected over the past three years to supplement historical data. The study suggests that while natural processes lead to the formation of blooms, they could be exacerbated by nutrients discharged from man-made sources, including runoff and sewage outfalls.

Among the key findings:

Pseudo-nitzschia is the culprit behind domoic acid. It’s been present along the Southern California coast for decades, but its role in wildlife mortality is recent and increasing.
The world’s highest domoic acid measurement in water occurred near San Pedro in March 2011. It was 52.3 micrograms per liter – about five times higher than a level of concern.
Through the years, researchers found a strong correlation between domoic acid in the water and impaired marine wildlife on shore.
Domoic acid is ever-present offshore, either in shellfish or the water. Some years it’s abundant, while other years it’s scarce.
Conditions are worse in the spring, due to seasonal upwelling of nutrients that spur plankton growth. The toxin is less abundant in the summer and winter.
Domoic acid in shellfish can occur at high concentrations off the coast of San Diego, Orange and Los Angeles counties, but it tends to be more prevalent in Ventura and Santa Barbara counties due to local environmental conditions.
Man-made sources of nutrients contribute to algal blooms, but that doesn’t explain disparities in time and location of some of the domoic acid outbreaks. Other environmental factors are likely in play.
The algae and its toxin diminish on the West Coast when water temperatures exceed 68 degrees Fahrenheit, apparently due to temperature sensitivity of the microorganisms.
Also, a warming Pacific Ocean appears to be helping spread Pseudo-nitzschia species farther north. For example, harmful algal blooms have been widespread along the west coast of North America from Central California to Alaska in the past two years, according to the study. Separately, harmful algae blooms have been reported along the Gulf Coast this summer and the governor of Florida declared a state of emergency for affected counties last week.

The USC study brings together diverse data and observations that shed light on the environmental conditions that promote harmful algal blooms. Of note, an extreme drought across the U.S. Southwest between 2014 and 2016 resulted in very low concentrations of domoic acid off the Southern California coast. The findings imply a link between surface waters flowing to the ocean, or other drought-related conditions, and coastal algal blooms.

Those nuances and uncertainties need further exploration to explain the regional and year-to-year variations favoring toxic algae – key steps before more reliable health forecasts can occur, the USC scientists say.

“Our findings summarize our present level of understanding with respect to this important animal and human health risk in Southern California waters and identify several avenues of research that might improve understanding, prediction and eventually prevention of these harmful events,” Smith said.

Study authors include Smith as lead and corresponding author, Caron as senior author, as well as Paige Connell, Erica L. Seubert, Avery O. Tatters and Alyssa G. Gellene of USC; Richard H. Evans of the Pacific Marine Mammal Center; Meredith D.A. Howard of the Southern California Coastal Water Research Project; Burton H. Jones of the Red Sea Research Center, King Abdullah University of Science and Technology, in Saudi Arabia; Susan Kaveggia of the International Bird Rescue in Los Angeles; Lauren Palmer of the Marine Mammal Care Center in Los Angeles; Astrid Schnetzer of North Carolina State University; and Bridget N. Seegers of the NASA Goddard Space Flight Center and the GESTAR/Universities Space Research Association.

Photo credit: Restless Mind Media/Fotolia


Linda Lindner
Urner Barry 1-732-240-5330 ext 223
Editorial Email: Editor@seafood.com
Reporter’s Email: llindner@urnerbarry.com

Copyright © 2018 Seafoodnews.com

Jul 10 2018

NOAA launches drones to sail the West Coast, survey anchovies, sardines and other fish

(Photo: Courtesy of John Gussman)

A bright orange and yellow drone boat will set sail in August, skimming down the West Coast as it collects data on fish and possibly changes the way experts study the ocean.

It’s one of five on a summer-long expedition to test the drones’ accuracy in assessing West Coast fish stocks. Those surveys help set limits on just how much fish can be caught each year.

“You want to use the best available science to come up with the best estimate of what the stock is, so that you can give a fair shake to the fishermen,” said Toby Garfield, director of environmental research division at Southwest Fisheries Science Center.

Typically, the surveys are done by ship. But the National Oceanic and Atmospheric Administration teamed up with Oceans Canada and Saildrone Inc. to test out the drones.

This is one alternative to collecting the data – one that may be able to go places ships can’t or to better estimate how many fish are out there, Garfield said.

Satellite imagery changed the way researchers looked at the ocean, he said, and “tools like Saildrone will give us another way to actually sample” it.

Two drones were launched last week from Neah Bay, Washington, and a second pair will be launched shortly. All four of those will follow the route of the NOAA ship Reuben Lasker.

Operators control the unmanned watercraft remotely from Saildrone’s headquarters in Alameda, California. Plans call for the drones to collect acoustic data on hake and pelagic fish, like sardines and anchovy, for up to 100 days.

 

Five Saildrones will be launched on the West Coast this summer. (Photo: Courtesy of John Gussman)

 

“Our ship is out there now. It’s out doing an 80-day survey from Vancouver Island down to the Mexican border,” Garfield said. “The two pairs are going to replicate that tract.”

Researchers will then compare the ship’s information to what’s collected by the drones to see if the new technology could be used to replicate some of the ship’s surveys.

They already know there will be differences, including that the drones will move slowly, about 1 or 2 knots.

There’s also a chance the drones could come closer to shore than the ships, which could help expand the surveys. Whether that’s possible depends on a lot of variables from the abundance of kelp to the number of recreational boats on the water.

That’s where the fifth drone comes in.

“That’s the one we’re going to try to use to explore whether we can come farther into shore,” Garfield said.

They’ll also want to use that drone to test whether it could sail in front of the ship to pinpoint the best spots to sample and, if instead of chasing the fish, they could use the drone in one area to track them as they swim by.

The fifth drone is scheduled to launch off Alameda on Aug. 13 and will be sailing for about six months. But it may not reach Ventura County.

“Originally, we were going to have the Saildrone operate all the way down to San Diego,” Garfield said Tuesday.

But the company had concerns about the traffic in the Santa Barbara Channel, as well as light winds in the summertime.

They’re going to make a decision closer to the date of the launch, he said. “It’s really going to depend on conditions.”

To follow the drones’ progress, go to NOAA’s blog at https://www.nwfsc.noaa.gov/news/blogs.


Original post and video: https://www.vcstar.com/

Jun 28 2018

Saildrone launch begins test to improve West Coast fisheries surveys

June 2018

Contributed by Michael Milstein

Two autonomous Saildrones launched from Neah Bay, Wash., Tuesday on a summer-long partnership between Saildrone Inc., NOAA Fisheries and Fisheries and Oceans Canada (DFO) to find out whether the wind and solar-powered vehicles can improve the efficiency and accuracy of fisheries surveys off the West Coast.

The two Saildrones will first head to the northern end of Vancouver Island and will then turn south, following a series of transects along the Coast south to San Francisco. Two other Saildrones will join the project fleet next week from Alameda, Calif., following transects from San Francisco south to the Southern California Bight. (See map.)

They will gather acoustic data on Pacific hake (whiting) and pelagic species such as sardines, anchovy and mackerel that make up many of the West Coast’s most important commercial fisheries. Fishermen unloaded 558 million pounds of hake worth about $47 million in ports such as Astoria, Ore., and Westport, Wash., in 2016.

The NOAA ship Reuben Lasker will also follow the transects and gather similar acoustic data for comparison. The Lasker is specially equipped with advanced echosounders for accurately surveying fish populations.

Technicians prepare the first two Saildrones for launch from Neah Bay, Wash. NOAA Fisheries/NWFSC

A fifth Saildrone launching from Alameda in August will test its value for conducting focused fisheries surveys, such gathering data in near-shore areas that large NOAA research ships cannot safely reach. The fifth vehicle will focus particularly on historically important areas for fisheries, such as Monterey Bay and off the San Francisco Bay Area.

“This partnership is putting some of the most important new marine technology to work for the West Coast,” said Toby Garfield, Acting Deputy Director of NOAA Fisheries’ Southwest Fisheries Science Center in La Jolla, Calif., and part of the team directing the fifth Saildrone. “The more complete and accurate data we have, the better decisions our fisheries managers can make in real terms of catch levels and seasons.”

The first two Saildrones left Neah Bay about 1 p.m. Tuesday. The vehicles were operating normally, scientists said, but must travel to Canadian waters before they begin collecting data on their transects heading south. The Saildrone team extended its thanks to the Makah Tribe, which authorized the launch from its marina in Neah Bay.

The northernmost surveys are particularly important for hake, a deep-water fish that supports an international fishery that the United States and Canada manage jointly under the Pacific Whiting Treaty. DFO scientists are assisting in management of the mission.

Please follow the progress of the West Coast Saildrone fisheries mission on the blog “Unmanned! Saildrone Expedition 2018.”

NOAA Fisheries’ Alaska Fisheries Science Center has been testing Saildrone technology, along with NOAA Research’s Pacific Marine Environmental Laboratory in Alaska for the past three years to gather oceanographic data, acoustic data on endangered North Pacific right whales, information on walleye pollock, and for prey surveys within the foraging range of a declining population of northern fur seals. This year, the focus in Alaska will be on studying abundance and distribution of Arctic cod in the Chukchi Sea.

The launch of Saildrones along the West Coast demonstrates NOAA Fisheries’ continued commitment to embrace new technologies to maximize efficiencies and advance its mission.

Teams ready a Saildrone for launch from Neah Bay, Wash. NOAA Fisheries/NWFSC


Originally posted: https://www.nwfsc.noaa.gov/

Jun 6 2018

Fish will migrate as temperatures warm, putting fisheries at risk

A new paper projects how warming ocean temperatures will affect the geographic distribution of 686 commercially important species around North America. Species migration and shifting home ranges have serious implications for natural resource management, particularly fisheries.

Read about it here:
http://sustainablefisheries-uw.org/fish-will-migrate-as-temperatures-warm/

Research Article:

Projecting shifts in thermal habitat for 686 species on the North American continental shelf

Jun 3 2018

Marine heatwaves are getting hotter, lasting longer and doing more damage

Marine heatwaves occur everywhere in the ocean. Credit: Eric Oliver/Dalhousie University

On land, heatwaves can be deadly for humans and wildlife and can devastate crops and forests.

Unusually warm periods can also occur in the ocean. These can last for weeks or months, killing off kelp forests and corals, and producing other significant impacts on marine ecosystems, fishing and aquaculture industries.

Yet until recently, the formation, distribution and frequency of marine heatwaves had received little research attention.

Long-term change

Climate change is warming ocean waters and causing shifts in the distribution and abundance of seaweeds, corals, fish and other marine species. For example, tropical fish species are now commonly found in Sydney Harbour.

But these changes in ocean temperatures are not steady or even, and scientists have lacked the tools to define, synthesize and understand the global patterns of marine heatwaves and their biological impacts.

At a meeting in early 2015, we convened a group of scientists with expertise in atmospheric climatology, oceanography and ecology to form a marine heatwaves working group to develop a definition for the phenomenon: A prolonged period of unusually warm water at a particular location for that time of the year. Importantly, marine heatwaves can occur at any time of the year, summer or winter.

With the definition in hand, we were finally able to analyze historical data to determine patterns in their occurrence.

Analysis of marine heatwave trends

Over the past century, marine heatwaves have become longer and more frequent around the world. The number of marine heatwave days increased by 54 per cent from 1925 to 2016, with an accelerating trend since 1982.

We collated more than 100 years of sea surface temperature data around the world from ship-based measurements, shore station records and satellite observations, and looked for changes in how often marine heatwaves occurred and how long they lasted.

We found that from 1925 to 1954 and 1987 to 2016, the frequency of heatwaves increased 34 per cent and their duration grew by 17 per cent.

These long-term trends can be explained by ongoing increases in ocean temperatures. Given the likelihood of continued ocean surface warming throughout the 21st century, we can expect to see more marine heatwaves globally in the future, with implications for marine biodiversity.

‘The Blob’ effect

Numbers and statistics are informative, but here’s what that means underwater.

 

Yearly count of marine heatwave days from 1900 to 2016, as a global average. Credit: Eric Oliver/Dalhousie University

A marine ecosystem that had 30 days of extreme heat in the early 20th century might now experience 45 days of extreme heat. That extra exposure can have detrimental effects on the health of the ecosystem and the economic benefits, such as fisheries and aquaculture, derived from it.

A number of recent marine heatwaves have done just that.

In 2011, a marine heatwave off western Australia killed off a kelp forest and replaced it with turf seaweed. The ecosystem shift remained even after water temperatures returned to normal, signalling a long-lasting or maybe even permanent change.

That same event led to widespread loss of seagrass meadows from the iconic Shark Bay area, with consequences for biodiversity including increased bacterial blooms, declines in blue crabs, scallops and the health of green turtles, and reductions in the long-term carbon storage of these important habitats.

Similarly, a marine heatwave in the Gulf of Maine disrupted the lucrative lobster fishery in 2012. The warm water in late spring allowed lobsters to move inshore earlier in the year than usual, which led to early landings, and an unexpected and significant price drop.

More recently, a persistent area of warm water in the North Pacific, nicknamed “The Blob”, stayed put for years (2014-2016), and caused fishery closures, mass strandings of marine mammals and harmful algal bloom outbreaks along the coast. It even changed large-scale weather patterns in the Pacific Northwest.

As global ocean temperatures continue to rise and marine heatwaves become more widespread, the marine ecosystems many rely upon for food, livelihoods and recreation will become increasingly less stable and predictable.

The climate change link

Anthropogenic, that is human-caused, climate change is linked to some of these recent marine heatwaves.

For example, human emissions of greenhouse gases made the 2016 marine heatwave in tropical Australia, which led to massive bleaching of the Great Barrier Reef, 53 times more likely to occur.

Even more dramatically, the 2015-16 marine heatwave in the Tasman Sea that persisted for more than eight months and disrupted Tasmanian fisheries and aquaculture industries was over 300 times more likely, thanks to anthropogenic climate change.

For scientists, the next step is to quantify future changes under different warming scenarios. How much more often will they occur? How much warmer will they be? And how much longer will they last?

Ultimately, scientists should develop forecasts for policy makers, managers and industry that could predict the future impacts of marine heatwaves for weeks or months ahead. Having that information would help fishery managers know when to open or close a fishery, aquaculture businesses to plan harvest dates and conservation managers to implement additional monitoring efforts.

Forecasts can help manage the risks, but in the end, we still need urgent action to curb greenhouse gas emissions and limit global warming. If not, marine ecosystems are set for an ever-increasing hammering from extreme ocean heat.

More information on this and related studies can be found on www.marineheatwaves.org.

May 31 2018

New Tool Helps Fisheries Avoid Protected Species In Near Real Time

EcoCast is a dynamic ocean management tool that aims to minimize fisheries bycatch and maximize fisheries target catch in near real time. Map shows daily relative bycatch target catch probabilities. Species weightings reflect management priorities and recent catch events. Environmental data are used to predict where species are likely to be each day.

 

New computer-generated daily maps will help fishermen locate the most productive fishing spots in near real time while warning them where they face the greatest risk of entangling sea turtles, marine mammals, and other protected species. Scientists developed the maps, the products of a system called EcoCast, to help reduce accidental catches of protected species in fishing nets.

Funded primarily by NASA with support from NOAA, California Sea Grant, and Stanford University, Ecocast was developed by NOAA Fisheries scientists and academic partners with input from fishermen and managers.

Using the swordfish fishery as an example, EcoCast incorporates data from tracking of tagged animals, remote sensing satellites and fisheries observers to help predict concentrations of the target species (broadbill swordfish) and three protected species (leatherback turtle, blue shark and California sea lion).

EcoCast will help fishermen, managers, scientists, and others understand in near real time where fishing vessels have the highest probability of catching targeted species and where there is risk of catching protected species. In doing so, EcoCast aims to improve the economic and environmental sustainability of fisheries that sometimes inadvertently catch and kill sensitive species. The first peer-reviewed description of the science behind the system appears this week in Science Advances.

“We’re harnessing the field of big data so that information on ocean conditions can be of most use – so fishermen can go where they’re likely to find the swordfish they want to catch but avoid the species that they do not want to catch,” said Elliott Hazen, a research ecologist at NOAA Fisheries’ Southwest Fisheries Science Center and lead author of the new paper.

Currently NOAA Fisheries closes a large area off the West Coast to the swordfish fishery seasonally to protect leatherback turtles, which travel widely, and can be caught incidentally in the nets. Fisheries managers could use EcoCast to outline small, “dynamic closures,” that shift according to the likely locations of the species they are trying to protect. Since they concentrate protection where it’s needed most, dynamic closures for leatherback sea turtles could be two to 10 times smaller than the current static closures while still safeguarding the species that need it, the scientists found.

“EcoCast pioneers a way of evaluating both conservation objectives and economic profitability for sustainable U.S. fisheries,” said Rebecca Lewison, a senior scientist on the project from San Diego State University and a co-author of the new paper. “By meeting both conservation and economic objectives, EcoCast is an important step forward in supporting species, their ecosystems and our local and state economies.” Dynamic closures could also support more “climate-ready” fisheries management approaches that adjust to changing ocean conditions as the climate shifts and changes over time. For instance, unusually warm conditions off the West Coast in 2014 and 2015 have driven shifts in fish and marine mammal species, forcing fishermen to adjust their efforts.

“EcoCast directly addresses both scientific priorities and fisheries management needs,” said Heidi Taylor of NOAA Fisheries’ West Coast Region. “The use of real-time environmental data to support dynamic ocean management provides an innovative approach to balance viable fisheries and protecting the ecosystem.”

She noted that fishermen participated throughout the development of EcoCast, which should help boost its usefulness to the fishing fleet. .

The EcoCast system is up and running now, producing color-coded maps posted online each day hosted via NOAA’s CoastWatch West Coast Regional Node. Managers can adjust the system to support additional fisheries, but this paper focused on reducing bycatch of leatherback turtles, blue sharks, and California sea lions in the West Coast drift gillnet fishery that targets swordfish.

EcoCast maps fishing areas in a blue-to-red scale that predicts the best waters to catch swordfish with little to no bycatch in darker shades of blue, with the greatest risk of encountering sea turtles, sea lions, and sharks shown in red. As the ocean conditions change, the dynamic map also changes. Managers can adjust the weighting of each species as risks change and the fishing season progresses.

“The fishermen will be willing to try this because they’re always looking for ways to do things differently, and better,” said Gary Burke, a drift gillnet fisherman in Southern California. “It’s not going to be perfect, because it’s a prediction, but it may give us access to information we haven’t had before.”

He said that fishermen have long watched ocean conditions such as sea surface temperatures as indicators of where the best fishing might be. The added information that EcoCast provides, such as the predicted concentrations of sea turtles, sea lions, and sharks, makes it a more powerful tool to help fishermen decide where – and where not – to fish.

“EcoCast simply would not have been possible a decade ago,” Hazen said. The increasing availability of satellite ocean data, the miniaturization of satellite tags for turtles and fish combined with faster and more powerful computers helped make it happen. Researchers are working to add data on additional species such as marine mammals to best reflect bycatch concerns.

“Now we can integrate all this information through complex statistical models that turn tens of thousands of data points into something more useful,” he said. “We’re putting the information directly in the hands of the fishers and managers.”

EcoCast is supported by a partnership that includes NOAA Fisheries, The University of California Santa Cruz, San Diego State University, Stanford University, Old Dominion University, The University of Maryland, drift gillnet fishermen, fisheries managers and other stakeholders.

“EcoCast is leading the way toward more dynamic management of marine resources,” said Woody Turner, program manager for ecological forecasting in NASA’s Applied Sciences Program.

Swordfish, Shutterstock/Joe Fish Flynn; Leatherback turtle with satellite tag, NOAA Fisheries/H. Harris (NMFS permit #1596-03); California sea lion with satellite tag, Dan Costa; Blue shark, NOAA Fisheries/Mark Conlin; Fishing vessel off the coast of southern California, NOAA Fisheries.

For more information:

Southwest Fisheries Science Center’s Environmental Research Division (ERD)

Related websites:

TurtleWatch – A product produced by NOAA’s Pacific Islands Fisheries Science Center to provides up-to-date information about the thermal habitat of loggerhead sea turtles in the Pacific Ocean north of the Hawaiian Islands.

WhaleWatch – A project coordinated by NOAA Fisheries’ West Coast Region to help reduce human impacts on whales.


Original post: https://swfsc.noaa.gov/

May 30 2018

Consequences of spatially variable ocean acidification in the California Current: Lower pH drives strongest declines in benthic species in southern regions while greatest economic impacts occur in northern regions

 

Emma E. Hodgsona, Isaac C. Kaplanb, Kristin N. Marshallc, Jerry Leonardc, Timothy E. Essingtona, D. Shallin Buschd, Elizabeth A. Fultone, f, Chris J. Harveyb, Albert Hermanng, h, Paul McElhanyb

  • a School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195-5020, USA
  • b Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, 2725 Montlake Blvd E, Seattle WA 98112, USA
  • c Fishery Resource Analysis and Monitoring Division, Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, 2725 Montlake Blvd E, Seattle WA 98112, USA
  • d Ocean Acidification Program, Office of Oceanic and Atmospheric Research and Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, 2725 Montlake Blvd E, Seattle WA 98112, USA
  • e CSIRO Oceans and Atmosphere, GPO Box 1538, Hobart, Tasmania 7001, Australia
  • f Centre for Marine Socioecology, University of Tasmania, 20 Castray Esplanade, Hobart, Tasmania 7004, Australia
  • g NOAA Pacific Marine Environmental Laboratory, 7600 Sand Point Way NE, Seattle WA 98115, USA
  • h Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, 3737 Brooklyn Ave NE, Seattle, WA 98105, USA

Abstract

Marine ecosystems are experiencing rapid changes driven by anthropogenic stressors which, in turn, are affecting human communities. One such stressor is ocean acidification, a result of increasing carbon emissions. Most research on biological impacts of ocean acidification has focused on the responses of an individual species or life stage. Yet, understanding how changes scale from species to ecosystems, and the services they provide, is critical to managing fisheries and setting research priorities. Here we use an ecosystem model, which is forced by oceanographic projections and also coupled to an economic input-output model, to quantify biological responses to ocean acidification in six coastal regions from Vancouver Island, Canada to Baja California, Mexico and economic responses at 17 ports on the US west coast. This model is intended to explore one possible future of how ocean acidification may influence this coastline. Outputs show that declines in species biomass tend to be larger in the southern region of the model, but the largest economic impacts on revenue, income and employment occur from northern California to northern Washington State. The economic consequences are primarily driven by declines in Dungeness crab from loss of prey. Given the substantive revenue generated by the fishing industry on the west coast, the model suggests that long-term planning for communities, researchers and managers in the northern region of the California Current would benefit from tracking Dungeness crab productivity and potential declines related to pH.

 

Access to full article can be found here: https://www.sciencedirect.com/science/article/pii/S0304380018301856