This document is subject to copyright. These currents are large and cyclical, taking the form of loops. By consuming sea urchins who are not similarly hidden, sea otters change sea urchin behavior. Find out more about how we calculated this figure here. Sea otters can greatly affect the environment they live in. 1982, Estes and Duggins 1995, Watson and Estes 2011, Burt et al. After the event, there were >1,000 views of the YouTube video within 12 hours. Although trophic cascades - the effect of apex predators on progressively lower trophic level species through top-down forcing - have been demonstrated in diverse ecosystems, the broader potential influences of trophic cascades on other species and ecosystem processes are not well studied. Vol 373, July 9, 2021, p. 223. doi: 10.1126/science.abf4557. The story was also updated July 23, 2021, to correct the description of otters' proton leaks. Sea otters can greatly affect the environment they live in. In fact, every species that feeds on these relatively chemically undefended macroalgae of the North Pacific may owe a debt to sea otters. 2009 May;152(1-4):357-67. doi: 10.1007/s10661-008-0321-7. That perspective is echoed in a soon to be published paper by University of Colorado Boulder ecologist Laura Dee, who points to the many indirect effects warmer temperatures can have on a species. CO2 concentration in the atmosphere has increased 40 percent since the beginning of the industrial revolution, causing global temperatures to rise, the authors write. It could be that warmer conditions slow the larvaes metabolism, prompting the predators to eat less, Rudolf says. These include increasing or decreasing prey, changing competitive abilities, shifting feeding rates and altering trophic cascades. By Lilian Carswell, Southern Sea Otter Recovery and Marine Conservation Coordinator,Ventura Fish and Wildlife Office, People traveling on Californias newly built Highway 1 in 1937 saw something astonishing. For general feedback, use the public comments section below (please adhere to guidelines). Finding the cellular source of sea otters souped-up metabolism could help scientists better understand how other marine mammals cope with frigid water. They enter a dormant state, biding their time under new kelp sprouts, and then revving back into action to eat the young seaweed. Our field studies were conducted in the early 1990s, "When I think about marine plants that can sequester carbon really well, it's typically the rooted ones," says Hughes. Continue reading with a Scientific American subscription. The return of these playful creatures doesn't just transform their ecosystems, it can turn them into a powerful carbon sink. She delights in all things creeping, crawling and curious, and studies human-dog coevolution as an anthropology Ph.D. student at Washington State University. doi: 10.1126/sciadv.aav1139. Another challenge faced by sea otters is the need to obtain enough calories to fuel their extremely high metabolic rates, which requires that sea otters consume the equivalent of 20-25% of their . Subscribers, enter your e-mail address for full access to the Science News archives and digital editions. Most of the participants go so far as to consider climate impacts when they make decisions in their personal lives. But researchers didnt understand the cellular origins of that revved-up metabolism for heat generation, Wright says. That's because it can grow really fast up to 60cm (24 inches) a day. sharing sensitive information, make sure youre on a federal Secure .gov websites use HTTPS Temperature-dependent viscosity had a significant effect on the carrying capacity and growth rates of consumers, as well as the average density of the top predator. If sea otters return, however, their feasting can put the herbivores in check and allow the kelp to flourish once again. Unauthorized use of these marks is strictly prohibited. When the sea otter returned and began to compete for these same shellfish, some saw the sea otter as an interloper, a destroyer of the oceans bounty. This puts them at a high potential for heat loss, especially because, unlike most marine mammals, sea otters do not have blubber to insulate them. Because sea otters (Enhydra lutris) exert a wide array of direct and indirect effects on coastal marine ecosystems throughout their geographic range, we investigated the potential influence of sea otters on the ecology of Bald Eagles (Haliaeetus leucocephalus) in the Aleutian Islands, Alaska, USA. Breen et al. Our results provide further evidence of the wide-ranging indirect effects of sea otter predation on nearshore marine communities and another apex predator, the Bald Eagle. "When we help restore missing keystone predators, we make things right in a lot of ways before we even recognise what some of those ways are," Lilian Carswell, the southern sea otter recovery coordinator for the US Fish and Wildlife Service, wrote in an email to the BBC. When enough sea otters are present, they have been found to keep the numbers of sea urchins down, preventing severe overgrazing (Estes and Palmisano, 1974). However, large numbers of sea otters can deplete shellfish populations, competing with fisheries for crabs, clams, and abalones. By this time, several generations of Californians had lived and died in a world essentially devoid of sea otters. The Lightning Talks: Sea Otters event occurred on Earth Day, 4/22/2021 from 6-7pm PT on YouTube Live. Because sea otters (Enhydra lutris) exert a wide array of direct and indirect effects on coastal marine ecosystems throughout their geographic range, we investigated the potential influence of sea otters on the ecology of Bald Eagles (Haliaeetus leucocephalus) in the Aleutian Islands, Alaska, USA. 2018). Some authorities also consider the marine otter (Lontra felina), a species that lives along the rocky Pacific coast of South America, to be a type of sea otter, because it hunts in shoreline and nearshore ocean areas, preying on crabs and other marine invertebrates. www.esajournals.org/doi/abs/10.1890/110176, Journal information: www.esajournals.org/doi/abs/10.1890/110176. Beyond species-specific considerations, any reintroduction effort must consider ecosystem-level implications. Share sensitive information only on official, secure websites. The ocean is a vast, continuous fluid. We studied the diets, productivity, and density of breeding Bald Eagles on four islands during 1993-1994 and 2000-2002, when sea otters were abundant and scarce, respectively. Consuming herbivorous urchins (genus Strongylocentrotus) enables kelp forests and the fish associated with them to flourish. Sea otters are creatures steeped in superlatives. Reisewitz, J. The Service aims to be inclusive, thoughtful, and scientifically rigorous as we consider actions to support sea otter recovery and ecosystem restoration now and in the future. The final registration number was 1,005 people. Since then, researchers have learned more about the complementary roles that other sea urchin predators, like sea stars, play in controlling overgrazing by sea urchins, but the conclusion that sea otters defend kelp patches and help to promote eventual regrowth has not changed. A new study shows how the high metabolism of adult and baby sea otters begins at the cellular level. We used hook-and-line surveys and underwater visual transects at shallow depths (2-25 m) across 20 rocky reef sites and a space-for-time substitution representing variation in sea otter occupation time. Updates? The talks are catered to a wide range of ages and no science background is required. For general inquiries, please use our contact form. Everything we know about ecology is that as things get more complex, they change, Rudolf says. Sea otters (Enhydra lutris) are a small mammal in the weasel family. Let us know if you have suggestions to improve this article (requires login). Digging would have stimulated sexual reproduction and increased seed set, an interaction that unraveled with otter extirpation. Over an ecosystem area of approximately 5.1 10 10 m 2, the effect of sea otter predation on living kelp biomass alone represents a 4.4-to 8.7-teragram increase in C storage. They found that otters "undoubtedly have a strong influence" on the cycle of CO2 storage. By the submission of this blog, there were 1,336 views. Official websites use .gov But since the return of the otters, the eelgrass has expanded by more than sixfold. Skeletal muscle thermogenesis enables aquatic life in the smallest marine mammal. Because sea otters (Enhydra lutris) exert a wide array of direct and indirect effects on coastal marine ecosystems throughout their geographic range, we investigated the potential influence of sea otters on the ecology of Bald Eagles (Haliaeetus leucocephalus) in the Aleutian Islands, Alaska, USA. Whereas urchin-dominated communities supported more diverse fish assemblages than kelp-dominated communities, this was not a simple effect of the otter-induced trophic cascade because all islands supported more diverse fish assemblages in 2000 than in the mid-1980s. Jaime Chambers was a 2021 AAAS Mass Media Fellow with Science News. On June 20, 1938, Life magazine published a photo of what it called one of the rarest sights on eartha large raft of sea otters near Bixby Bridge, south of Monterey. Omissions? However, it eventually began to grow more rapidly, numbering about 100 at the time of the most recent range-wide count in 2019. A lock () or https:// means youve safely connected to the .gov website. Some of these effects are perceived as beneficial to people, and others are perceived as negative. Blue rockfish in a giant kelp forest off North Monastery Beach, Carmel, California, 2022. A. Estes, C.A. The https:// ensures that you are connecting to the Scientists still need to understand the reasons behind the otters disappearances, but Rasher Is hopeful. As sea otters declined (for reasons scientists are still trying to understand), their favorite preysea urchinsexploded in number. That mission has never been more important than it is today. The digital emissions from this story are an estimated 1.2g to 3.6g CO2 per page view. However, copper rockfish fishable biomass was negatively correlated with canopy kelp stipe density, likely due to the successional transition as sea otters return to an area from the disturbance-tolerant annual kelp Nereocystis to the perennial kelp Macrocystis. Effects of predator depletion or recovery are frequently accompanied by time lags, which are often context-dependent. Contrary to our hypothesis, we found no appreciable enrichment of the 13C signature across the gradient of sea otter occupation time associated with an increase in the amount of kelp-derived carbon within fish. Thanks for reading Scientific American. "They miraculously don't eat the seagrass," says Hughes. I believe my capstone project was successful in accomplishing all of the learning objectives. When sea otters are absent, urchins decimate kelp, resulting in low net primary productivity. The sea otters keystone role in nearshore marine ecosystems was first recognized in 1974, initiating an extensive body of work on sea otters indirect effects, including increases in the abundance of kelp-associated finfish. Otters indirect effects on coastal ecosystems can also follow pathways other than the otter-urchin-kelp trophic cascade. government site. 2015 Mar;177(3):645-655. doi: 10.1007/s00442-014-3149-6. Breeding success and productivity of Bald Eagles also increased during this time period, which may be due to the higher nutritional quality of avian prey consumed in later years. Although abalone are a favorite prey item, they make up only a small proportion of the diet of the sea otter population overall, the remainder consisting of several dozen species of marine invertebrates, including many kinds of crabs, clams, sea urchins, mussels, chitons, octopuses, sea stars, and marine worms. 12201 Sunrise Valley Drive Reston, VA 20192, Indirect food web interactions: Sea otters and kelp forest fishes in the Aleutian archipelago, S.E. Because these proton leaks increase the amount of energy lost as heat, otters need to eat more food to make up for that lost energy, revving up their metabolism. "If ecologists can get a better handle on what these impacts are, there might be opportunities for win-win conservation scenarios, whereby animal species are protected or enhanced, and carbon gets sequestered," he said. Its in their muscles. Explore our digital archive back to 1845, including articles by more than 150 Nobel Prize winners. The site is secure. The survey itself showed that people learned something new that they had not known before. While every effort has been made to follow citation style rules, there may be some discrepancies. The other is a metabolism more than double that of any land mammal of the same size. Some of these effects are perceived as beneficial to people, and others are perceived as negative. If you liked this story,sign up for the weeklybbc.comfeatures newsletter, called "The Essential List". Using data on the rate of kelp growth and its density at sites with and without otters, they found that the presence of sea otters across rocky reef habitat in the study area, covering 51,551 . Thank you for taking time to provide your feedback to the editors. Corrections? Registration occurred through the Seattle Aquarium website, and was advertised in multiple ways (facebook ads, Seattle Aquarium members, staff and volunteers, UW SMEA department listserv, UW PCC listserv, etc). Testing the nutritional-limitation, predator-avoidance, and storm-avoidance hypotheses for restricted sea otter habitat use in the Aleutian Islands, Alaska. Apart from any fair dealing for the purpose of private study or research, no Then, using a device called a respirometer, researchers measured otter muscle cells respiratory capacity in different states of oxygen flow compared with other animals including humans, Iditarod sled dogs and elephant seals. Thanks for reading Scientific American. T. Wright (Image obtained under USFWS Marine MammalPermitNo. From the moment Berings men returned home to Russia with sea otter pelts, the species was in mortal danger. And so it essentially protects the seagrass.". Restoring otter populations could rein in the urchins and help protect the larger ecosystem, and ecologists are increasingly interested in applying this idea more broadly. Overall, indirect effects of temperature via changes in viscosity were subtle in comparison to the indirect effect of temperature via trophic interactions. 4. And a 2020 study found that the monetary benefit of sea otters due their restoration of kelp habitat and associated increase in fish stocks, carbon sequestration, and ecotourism value outweighs the losses to shellfish fisheries. Int J Parasitol. Their massive appetites can diminish fishing opportunities for commercial operations and subsistence-based Indigenous communities. The loss or recovery of apex predators can have profound positive or negative ecological and socio-economic impacts. MeSH Several otters are available for an experiment. Registration occurred through the Seattle Aquarium website, and was advertised in multiple ways (facebook ads, Seattle Aquarium members, staff and volunteers, UW SMEA department listserv, UW PCC listserv, etc). Comparing kelp density with otters and kelp density without otters, they found that "sea otters have a positive indirect effect on kelp biomass by preying on sea urchins, a kelp grazer." 1982, Estes and Duggins 1995, Watson and Estes 2011, Burt et al. "A kelp frond that drifts to the seafloor and decomposes, that carbon might be trapped in the sediments for millennia, even millions of years," says Pearson. Because of the high rate of uptake of atmospheric CO2, it has been hypothesized that sea otters might increase the rate While some Native peoples within the sea otters range had traditionally conducted local hunting of sea otters, the scale of slaughter in the maritime fur trade was unprecedented, nearly eliminating sea otters from their global range. Baby otters dont yet have the muscle mass to stay warm through these leaks, but their muscle cells generate heat at adult rates, the researchers found, showing that proton leak begins early. That means it's pulling carbon from the atmosphere faster than a slower growing plant (though kelp is technically an alga). R Soc Open Sci. Read about my event of short engaging lightning talks in fulfillment of the UW PCC Graduate Certificate in Climate Science. University of California - Santa Cruz. We used the overexploitation, recovery and subsequent collapse of sea otter (Enhydra lutris) populations in the Aleutian archipelago to explore if and how the abundance and diet of kelp forest fishes are influenced by a trophic cascade linking sea otters with sea urchins and fleshy macroalgae. The appetite of the sea otter is a threat to individual abalone who have not hidden themselves in deep rocky crevices, but where sufficient crevice habitat is available, this same appetite brings benefits to abalone populations. Fish and Wildlife Service. Sea otters can greatly affect the environment they live in. Bethesda, MD 20894, Web Policies Enhydra lutris is the furriest animal on Earth, with up to 140,000 hairs on every square centimeter of its body meaning its hairs are 700 times as dense as those on a human head. Create your free account or Sign in to continue. They will remain accessible to anyone who wants to watch them in the future. HHS Vulnerability Disclosure, Help Sea otters are also the smallest marine mammal in the northern hemisphere. Researchers have proposed that sea otters and their evolutionary progenitors could be indirectly responsible for evolution of the unusually large body sizes of the abalone species in the North Pacific Ocean. Overall, we found higher fishable biomass of copper rockfish at sites where sea otter occupation was greatest, and evidence that copper rockfish catch rates were higher in relatively larger kelp beds. Springer-Verlag 2005. These slugs and snails often don't eat the seagrass; instead they scrape away the algae that grows on the grass, which allows the seagrass to absorb more sunlight and grow more efficiently. And the insulating properties of sea otters fur the densest on the planet cant fully protect them from losing too much heat. It was 1742. Get weekly and/or daily updates delivered to your inbox. ", More information: Ecosphere 7(12) Article e01604. Knowledge awaits. Our mission is to provide accurate, engaging news of science to the public. Is that sea otter stealing your lunch -- or making it? While much focus has been placed on the effects of heat stress on scleractinian corals-including bleaching, mortality, and loss of reef structural complexity-and many studies have documented changes to reef fish communities arising indirectly from shifts in benthic composition, the direct impacts . Direct effects can be thought of as any change to prey availability via sea otter predation directly, while indirect effects can be thought of an any alteration to the broader ecosystem (i.e. Among their favorite foods are sea urchins, which are easy to catch and dense in calories. Ecosystem Effects of Sea Otters . Temperature-dependent viscosity had a significant effect on the carrying capacity and growth rates of consumers, as well as the average density of the top predator. Many climate impact studies on species have not adequately acknowledged this kind of ecosystem complexity as a factor, according to Rasher and other scientists. Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. National Library of Medicine When the mustelids bring down the numbers of crabs, grazing organisms that the crabs eat rebound. In general, currents carry warm water from . You can unsubscribe at any time and we'll never share your details to third parties. Instead of roving about and attacking the holdfasts that anchor living kelp to the rocky ocean floor, creating urchin barrens, fearful sea urchins adopt a sit-and-wait strategy, hiding in deep crevices and eating only those pieces of kelp that break off and drift down. The sea otter is the largest otter, reaching 100160 cm (4065 inches) long and weighing 1640 kg (3590 pounds) when fully grown. 4. https://www.youtube.com/watch?v=gZmiqJ12Mms. The author granted permission for the file to be printed and for the text to be copied and pasted. 2016. One of the easiest ways that anyone can support bird habitat conservation is by buying duck stamps. Similarly, Pace (1981) experimentally removed sea urchins in Barkley Sound (otter-absent region, this study) and found higher kelp population densities and lower depth . Direct and indirect effects of temperature and prey abundance on bald eagle reproductive dynamics. Our editors will review what youve submitted and determine whether to revise the article. Accessibility The idea of restoring predators to blunt the impacts of warming has been simmering in ecology for decades. This story was updated August 24, 2021, to correct the description of surface area's effect on heat loss. Careers. Simenstad et al. Based on the December 2012 price on the European Carbon Exchange ($47 [36] per tonne of carbon), Estes' paper that year estimated that sea otter presence in their North Pacific study area was worth up to $408m (296m). A new study by two UC Santa Cruz researchers suggest that a thriving sea otter population that keeps sea urchins in check will in turn allow kelp forests to prosper. Sea otter populations along British Columbia's (BC) Central Coast are growing and expanding their range at a rapid rate. Increases in kelp and seagrass due to sea otters can translate into increased carbon sequestration. Epub 2014 Nov 22. Get great science journalism, from the most trusted source, delivered to your doorstep. The final registration number was 1,005 people. This site uses cookies to assist with navigation, analyse your use of our services, collect data for ads personalisation and provide content from third parties. The frequency of sea otter pups, rock greenling (Hexagammus lagocephalus), and smooth lumpsuckers (Aptocyclus ventricosus) in the eagle's diet declined with corresponding increases in Rock Ptarmigan (Lagopus mutus), Glaucous-winged Gulls (Larus glaucescens), Atka mackerel (Pleurogrammus monopterygius), and various species of seabirds during the period of the recent otter population decline. . You might have reduced survival because of the direct effect of heat, he says, but [changes caused by] predation and competition can compensate for those direct losses. Our fish studies focused on rock greenling (Hexagrammos lagocephalus), the numerically dominant species in this region. So what you would expect to happen with the loss of a species in the absence of climate change is not whats going to happen with the loss of that species in the presence of climate change . And this paper is the holy grail of showing that interaction.. Bringing sea otters back to the Pacific coast pays off, but not for everyone, How kelp forests off California are responding to an urchin takeover, 50 years ago, atomic testing created otter refugees, Heres what we know about upcoming vaccines and antibodies against RSV, Pets and people bonded during the pandemic. At the beginning and end of the event, I conducted a survey using PollEverywhere to learn more about the audience and to gauge the effectiveness of our climate communication. We found no evidence that sea otter occupation time or any other factor tested affected rockfish or greenling density observed on underwater visual surveys. ?? "But animals the world over, working in different ways to influence the carbon cycle, might actually have a large impact. As the marine mammal species that it protects return to ecologically effective population sizes, we learn what their roles once were, and more importantly, how they might contribute to ecosystem resilience in the future. After wolves were reintroduced in 1995, though, they became the main cause of elk mortality and created a steadier carrion supply that helped sustain other animals throughout the cold months. (1977a) identified several interaction web pathways by which sea otters might influence the behavior and population biology of kelp forest fishes, including direct Credit: Nick Higgins. Since then, conservation efforts have allowed the otters to rebound somewhat, but some 2,500 miles (4,000km) of coastline in their historic range is still devoid of the furry mammals. Sea otters feed mainly on sea urchins and on crabs and other shellfish. Epub 2005 Sep 27. amount of work on sea otter-sea urchin-macroalgal relationships, our study focuses on the indirect effects of this trophic cascade on kelp forest fishes. The captured prey is eaten at sea while the otter swims on its back. 2023 Scientific American, a Division of Springer Nature America, Inc. With no otters around, sea urchins graze voraciously on living kelp. and transmitted securely. Join one million Future fans by liking us onFacebook, or follow us onTwitterorInstagram. The Seattle Aquarium lightning talks are recorded and available to watch for free on YouTube. Producing heat this way helps the animals stay comfortable in 0 C Pacific waters. An official website of the United States government. I think were all coming to realize that theres going to be a lot of synergies between species loss and climate change, says Hillary Young, an ecologist at the University of California, Santa Barbara, who was not involved in the new study. I believe the speakers did an amazing job at articulating climate change through an animal lens, and they highlighted multiple ways that climate change will impact the marine environment and how sea otters can help mitigate those changes. They are a keystone species, which means they have a big impact on keeping their ecosystem balanced. Because sea otters (Enhydra lutris) exert a wide array of direct and indirect effects on coastal marine ecosystems throughout their geographic range, we investigated the potential influence of sea otters on the ecology of Bald Eagles (Haliaeetus leucocephalus) in the Aleutian Islands, Alaska, USA. Sea otters have voracious appetites, eating about a quarter of their body weight every day (Credit: Getty Images). We measured the abundance of sea urchins (biomass density), kelp (numerical density) and fish (Catch per unit effort) at four islands in the mid-1980s (when otters were abundant at two of the islands and rare at the two others) and in 2000 (after otters had become rare at all four islands). Although the indirect effects of sea otters are widely known, this example is unique because the food-web pathway transcended five species and several trophic levels in . Learn more about structure and function of the surrounding ecosystem. This explanatory language, which accompanied the 2021 Appropriations Act, also instructed the Service to study the feasibility and cost of reestablishing sea otters on the Pacific Coast of the contiguous United States. The emissions from travel it took to report this story were 0kg CO2. The biologist attributed this improvement from their near-extermination just a few years earlier to the states total protection. Bald Eagles depend on nearshore marine communities for most of their prey in this ecosystem, so we predicted that the recent decline in otter populations would have an indirect negative effect on diets and demography of Bald Eagles. What was Rosalind Franklins true role in the discovery of DNAs double helix. 2005 Oct;35(11-12):1155-68. doi: 10.1016/j.ijpara.2005.07.002. Medical research advances and health news, The latest engineering, electronics and technology advances, The most comprehensive sci-tech news coverage on the web. 2013). In the 1960s, they reached the waters of Gorda and San Simeon, north of Morro Bay, prime fishing grounds for a lucrative commercial abalone fishery that had begun in earnest after World War II. This can be done in a creative and captivating way, leaving audiences with one or two main take away points. Wilmers and Estes acknowledge that a spreading otter population won't solve the problem of higher CO2 in the atmosphere but argue that the restoration and protection of otters is an example how managing animal populations can affect ecosystems abilities to sequester carbon. . It inhabits coastal waters from the Kuril Islands to the Aleutian Islands southward to the coast of California. When kelp dies and washes ashore, carbon returns to the atmosphere during decomposition. In the case of the Aleutian Islands reefs, for example, if the scientists had simply exposed living reef samples to warmer and more acidic water in the lab, they might have incorrectly concluded the reefs were in no great danger because those impacts alone only slightly softened their skeleton. During the event, we received 395 chat messages in the YouTube live chat and had 364 concurrent viewers at the peak. Federal government websites often end in .gov or .mil. They note that markets have been established in Europe and the United States to trade carbon credits and thus inject an economic incentive into either reducing CO2 output or increasing CO2 sequestration. Effects of the Exxon Valdez Oil Spill Transmission of Toxoplasma: clues from the study of sea otters as sentinels of Toxoplasma gondii flow into the marine environment. The population off Big Sur was the most isolated of all of these, separated from any other surviving sea otters by about 2,000 miles. Please enable it to take advantage of the complete set of features! Today, our mission remains the same: to empower people to evaluate the news and the world around them.