Quantcast

New Study Reveals Whales as Marine Ecosystem Engineers

Baleen and sperm whales, known collectively as the great whales, include the largest animals in the history of life on Earth. Though large in size, whales have long been considered too rare to make much of a difference in the ocean, and the focus of much marine ecological research has been on smaller organisms, such as algae and planktonic animals. While these small organisms are essential to life in the sea, they are not the whole story. As great whales recover from centuries of overhunting, scientists are beginning to appreciate their roles as ecosystem engineers of the ocean.

Whales transfer nutrients from deep to surface water via plumes of fecal matter. Image credit: Roman et al.

A recent synthesis, published in Frontiers in Ecology and the Environment, evaluates decades of research on the ecological role of great whales. The authors, led by Joe Roman at the University of Vermont, suggest that the influence of these animals has been substantially undervalued because, until now, scientists have underestimated the degree to which the decline in whale population has altered marine ecosystems.

Commercial whaling dramatically reduced the abundance of great whales—by at least 66 percent and perhaps as high as 90 percent, according to some estimates—but recovery is possible, and potentially critical for ocean resiliency.

Among their many ecological functions, whales recycle nutrients and enhance primary productivity, locally and on a regional scale. Whales mix the water column, and after feeding at depth, release surface plumes of fecal material. This “whale pump” supplies iron and nitrogen—essentially fertilizers—to primary producers in the surface ocean. Further, the migrations of baleen whales between highly productive, high-latitude feeding and low-latitude calving grounds are among the longest annual movements of mammals. By fasting in these winter calving grounds near the equator, humpback whales, for example, release nitrogen in the form of urea into comparatively nutrient-poor areas—transporting nutrients nearly 10,000 kilometers on the “great whale conveyor belt.”

After feeding at depth, sperm whales off the coast of Sri Lanka return to the surface—and poop. This “whale pump” provides many nutrients, in the form of feces, to support plankton growth. It’s one of many examples of how whales maintain the health of oceans. Photo credit: Tony Wu

Sometimes, commercial fishermen have seen whales as competition. But this new paper summarizes a strong body of evidence that indicates the opposite can be true: whale recovery “could lead to higher rates of productivity in locations where whales aggregate to feed and give birth,” supporting more robust fisheries.

Whales, as one of the longer-lived species in marine systems, can ease the impact of perturbations in climate, predation and productivity. The continued recovery of great whales may help buffer marine ecosystems from destabilizing stresses and could lead to higher rates of productivity in locations where whales aggregate to feed and give birth.

And when they die, many whale carcasses sink to dark depths of the ocean—delivering massive pulses of organic material to a realm that is typically nutrient and energy impoverished. A 40-ton gray whale, for example, provides more than 2,000 times the background carbon flux that would typically rain down on the area underlying the carcass in an entire year.

“Whales appear to harbor a specialized suite of animals in the deep sea, with many species requiring whale falls to complete their life cycles and persist in the ocean,” said Craig Smith, co-author and Oceanography Professor at the University of Hawai‘i at Mānoa. “When whales were removed from the ocean by whalers, these whale-fall specialists lost their essential habitat.”

Fallen whale carcasses are home to species that rely on the unique habitat. Photo credit: C.Smith

“Our models show that the earliest human-caused extinctions in the sea may have been whale fall invertebrates, species that evolved adaptations to live on whale falls,” according to Smith. “As a result of 1,000 years of whaling by humans, many of these whale-fall species may have disappeared before we had a chance to discover them.”

Reflecting on the recent synthesis of data, Roman stated, “This warrants a shift in view from whales being positively valued as exploitable goods—or negatively valued because they compete with people for marine fish—to one what recognizes that these animals play key roles in healthy marine ecosystems, providing services to human societies.”

Show Comments ()

EcoWatch Daily Newsletter

Mizina / iStock / Getty Images

By Ryan Raman, MS, RD

Oats are widely regarded as one of the healthiest grains you can eat, as they're packed with many important vitamins, minerals, and fiber.

Read More Show Less
JPMorgan Chase building in New York City. Ben Sutherland / CC BY 2.0

By Sharon Kelly

A report published Wednesday names the banks that have played the biggest recent role in funding fossil fuel projects, finding that since 2016, immediately following the Paris agreement's adoption, 33 global banks have poured $1.9 trillion into financing climate-changing projects worldwide.

Read More Show Less
Sponsored
Sriram Madhusoodanan of Corporate Accountability speaking on conflict of interest demand of the People's Demands at a defining action launching the Demands at COP24. Corporate Accountability

By Patti Lynn

2018 was a groundbreaking year in the public conversation about climate change. Last February, The New York Times reported that a record percentage of Americans now believe that climate change is caused by humans, and there was a 20 percentage point rise in "the number of Americans who say they worry 'a great deal' about climate change."

Read More Show Less
The head of England's Environment Agency has urged people to stop watering their lawns as a climate-induced water shortage looms. Pexels

England faces an "existential threat" if it does not change how it manages its water, the head of the country's Environment Agency warned Tuesday.

Read More Show Less
Pexels

By Jessica Corbett

A new analysis revealed Tuesday that over the past two decades heat records across the U.S. have been broken twice as often as cold ones—underscoring experts' warnings about the increasingly dangerous consequences of failing to dramatically curb planet-warming emissions.

Read More Show Less
Sponsored
A flock of parrots in Telegraph Hill, San Francisco. ~dgies / Flickr

By Madison Dapcevich

Ask any resident of San Francisco about the waterfront parrots, and they will surely tell you a story of red-faced conures squawking or dive-bombing between building peaks. Ask a team of researchers from the University of Georgia, however, and they will tell you of a mysterious string of neurological poisonings impacting the naturalized flock for decades.

Read More Show Less
Fire burns in the North Santiam State Recreational Area on March 19. Oregon Department of Forestry

An early-season wildfire near Lyons, Oregon burned 60 acres and forced dozens of homes to evacuate Tuesday evening, the Oregon Department of Forestry (ODF) said, as KTVZ reported.

The initial cause of the fire was not yet known, but it has been driven by the strong wind and jumped the North Santiam River, The Salem Statesman Journal reported. As of Tuesday night, it threatened around 35 homes and 30 buildings, and was 20 percent contained.

Read More Show Less
Edwin Hardeman is the plaintiff in the first U.S. federal trial claiming that Roundup causes cancer. NOAH BERGER / AFP / Getty Images

A second U.S. jury has ruled that Roundup causes cancer.

The unanimous verdict was announced Tuesday in San Francisco in the first federal case to be brought against Monsanto, now owned by Bayer, alleging that repeated use of the company's glyphosate-containing weedkiller caused the plaintiff's cancer. Seventy-year-old Edwin Hardeman of Santa Rosa, California said he used Roundup for almost 30 years on his properties before developing non-Hodgkin's lymphoma.

The decision comes less than a year after a jury awarded $289 million to Bay-area groundskeeper Dewayne Johnson over similar claims. The amount was later reduced to $78 million.

"Today's verdict reinforces what another jury found last year, and what scientists with the state of California and the World Health Organization have concluded: Glyphosate causes cancer in people," Environmental Working Group President Ken Cook said in a statement. "As similar lawsuits mount, the evidence will grow that Roundup is not safe, and that the company has tried to cover it up."

Judge Vince Chhabria has split Hardeman's trial into two phases. The first, decided Tuesday, focused exclusively on whether or not Roundup use caused the plaintiff's cancer. The second, to begin Wednesday, will assess if Bayer is liable for damages.

"We are disappointed with the jury's initial decision, but we continue to believe firmly that the science confirms glyphosate-based herbicides do not cause cancer," Bayer spokesman Dan Childs said in a statement reported by The Guardian. "We are confident the evidence in phase two will show that Monsanto's conduct has been appropriate and the company should not be liable for Mr. Hardeman's cancer."

Some legal experts said that Chhabria's decision to split the trial was beneficial to Bayer, Reuters reported. The company had complained that the jury in Johnson's case had been distracted by the lawyers' claims that Monsanto had sought to mislead scientists and the public about Roundup's safety.

However, a remark made by Chhabria during the trial and reported by The Guardian was blatantly critical of the company.

"Although the evidence that Roundup causes cancer is quite equivocal, there is strong evidence from which a jury could conclude that Monsanto does not particularly care whether its product is in fact giving people cancer, focusing instead on manipulating public opinion and undermining anyone who raises genuine and legitimate concerns about the issue," he said.

Many regulatory bodies, including the U.S. Environmental Protection Agency, have ruled that glyphosate is safe for humans, but the World Health Organization's International Agency for Research on Cancer found it was "probably carcinogenic to humans" in 2015. A university study earlier this year found that glyphosate use increased cancer risk by as much as 41 percent.

Hardeman's lawyers Jennifer Moore and Aimee Wagstaff said they would now reveal Monsanto's efforts to mislead the public about the safety of its product.

"Now we can focus on the evidence that Monsanto has not taken a responsible, objective approach to the safety of Roundup," they wrote in a statement reported by The Guardian.

Hardeman's case is considered a "bellwether" trial for the more than 760 glyphosate cases Chhabria is hearing. In total, there are around 11,200 such lawsuits pending in the U.S., according to Reuters.

University of Richmond law professor Carl Tobias told Reuters that Tuesday's decision showed that the verdict in Johnson's case was not "an aberration," and could possibly predict how future juries in the thousands of pending cases would respond.