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.
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.”
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.”
“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.”
A tornado tore through a city north of Birmingham, Alabama, Monday night, killing one person and injuring at least 30.
- Tornadoes and Climate Change: What Does the Science Say ... ›
- Tornadoes Hit Unusually Wide Swaths of U.S., Alarming Climate ... ›
- 23 Dead as Tornado Pummels Lee County, AL in Further Sign ... ›
EcoWatch Daily Newsletter
By David Konisky
On his first day in office President Joe Biden started signing executive orders to reverse Trump administration policies. One sweeping directive calls for stronger action to protect public health and the environment and hold polluters accountable, including those who "disproportionately harm communities of color and low-income communities."
Michael S. Regan, President Biden's nominee to lead the U.S. Environmental Protection Agency, grew up near a coal-burning power plant in North Carolina and has pledged to "enact an environmental justice framework that empowers people in all communities." NCDEQ
- Report Urges Biden to Reverse Trump's Environmental Rollbacks ›
- US Environmental Protection Agency (EPA) ›
- Biden's EPA Pick Michael Regan Urged to Address Environmental ... ›
- Biden Faces Pressure to Tackle 'Unfunded' Toxic Waste Sites ... ›
By Katherine Kornei
Clear-cutting a forest is relatively easy—just pick a tree and start chopping. But there are benefits to more sophisticated forest management. One technique—which involves repeatedly harvesting smaller trees every 30 or so years but leaving an upper story of larger trees for longer periods (60, 90, or 120 years)—ensures a steady supply of both firewood and construction timber.
A Pattern in the Rings<p>The <a href="https://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/coppice-standards-0" target="_blank">coppice-with-standards</a> management practice produces a two-story forest, said <a href="https://www.researchgate.net/profile/Bernhard_Muigg" target="_blank">Bernhard Muigg</a>, a dendrochronologist at the University of Freiburg in Germany. "You have an upper story of single trees that are allowed to grow for several understory generations."</p><p>That arrangement imprints a characteristic tree ring pattern in a forest's upper story trees (the "standards"): thick rings indicative of heavy growth, which show up at regular intervals as the surrounding smaller trees are cut down. "The trees are growing faster," said Muigg. "You can really see it with your naked eye."</p><p>Muigg and his collaborators characterized that <a href="https://ltrr.arizona.edu/about/treerings" target="_blank">dendrochronological pattern</a> in 161 oak trees growing in central Germany, one of the few remaining sites in Europe with actively managed coppice-with-standards forests. They found up to nine cycles of heavy growth in the trees, the oldest of which was planted in 1761. The researchers then turned to a historical data set — more than 2,000 oak <a href="https://eos.org/articles/podcast-discovering-europes-history-through-its-timbers" target="_blank" rel="noopener noreferrer">timbers from buildings and archaeological sites</a> in Germany and France dating from between 300 and 2015 — to look for a similar pattern.</p>
A Gap of 500 Years<p>The team found wood with the characteristic coppice-with-standards tree ring pattern dating to as early as the 6th century. That was a surprise, Muigg and his colleagues concluded, because the first mention of this forest management practice in historical documents occurred only roughly 500 years later, in the 13th century.</p><p>It's probable that forest management practices were not well documented prior to the High Middle Ages (1000–1250), the researchers suggested. "Forests are mainly mentioned in the context of royal hunting interests or donations," said Muigg. Dendrochronological studies are particularly important because they can reveal information not captured by a sparse historical record, he added.</p><p>These results were <a href="https://www.nature.com/articles/s41598-020-78933-8" target="_blank">published in December in <em>Scientific Reports</em></a>.</p><p>"It's nice to see the longevity and the history of coppice-with-standards," said <a href="https://www.teagasc.ie/contact/staff-directory/s/ian-short/" target="_blank">Ian Short</a>, a forestry researcher at Teagasc, the Agriculture and Food Development Authority in Ireland, not involved in the research. This technique is valuable because it promotes conservation and habitat biodiversity, Short said. "In the next 10 or 20 years, I think we'll see more coppice-with-standards coming back into production."</p><p>In the future, Muigg and his collaborators hope to analyze a larger sample of historic timbers to trace how the coppice-with-standards practice spread throughout Europe. It will be interesting to understand where this technique originated and how it propagated, said Muigg, and there are plenty of old pieces of wood waiting to be analyzed. "There [are] tons of dendrochronological data."</p><p><em><a href="mailto:email@example.com" target="_blank" rel="noopener noreferrer">Katherine Kornei</a> is a freelance science journalist covering Earth and space science. Her bylines frequently appear in Eos, Science, and The New York Times. Katherine holds a Ph.D. in astronomy from the University of California, Los Angeles.</em></p><p><em>This story originally appeared in <a href="https://eos.org/articles/tree-rings-reveal-how-ancient-forests-were-managed" target="_blank">Eos</a></em> <em>and is republished here as part of Covering Climate Now, a global journalism collaboration strengthening coverage of the climate story.</em></p>
Earth's ice is melting 57 percent faster than in the 1990s and the world has lost more than 28 trillion tons of ice since 1994, research published Monday in The Cryosphere shows.
By Jewel Fraser
Noreen Nunez lives in a middle-class neighborhood that rises up a hillside in Trinidad's Tunapuna-Piarco region.