Subscribe free to our newsletters via your
. Earth Science News .




WHALES AHOY
A whale of a tale
by Staff Writers
Boston MA (SPX) Sep 23, 2015


"From one point of view, whales look like carnivores," Girguis said. "They have the same kind of microbes that we find in lions and tigers that have very meat-rich diets. But they also have abundant communities of anaerobic bacteria, similar to those that ruminants use to break down cellulose."

To some, it may not come as a surprise to learn that the great whales are carnivores, feeding on tiny shrimp-like animals such as krill. Moreover, it might not be surprising to find that the microbes that live in whale guts -the so-called microbiome- resemble those of other meat eaters.

But scientists now have evidence that the whales' microbiome shares traits with creatures not known to eat meat - cows.

Led by Peter Girguis, Professor of Organismic and Evolutionary Biology, scientists have found that the gut microbiome of right whales and other baleen species shares characteristics with both cows and meat-eating predators. The dual microbial communities allow whales to extract the most nutrition possible from their diet, digesting not only the copepods they eat, but their chitin-rich shells as well. The study is described in a September 22 paper in Nature Communications.

Among the co-authors of the paper are: James McCarthy, Professor of Biological Oceanography and Alexander Agassiz Professor of Biological Oceanography in the Museum of Comparative Zoology, Annabel Biechman, '14, now a graduate student at UCLA, Joe Roman from the University of Vermont, Jarrod Scott and David Emerson, both from the Bigelow Laboratory for Ocean Sciences in Maine and Jon Sanders, a former graduate student in Girguis' lab.

"From one point of view, whales look like carnivores," Girguis said. "They have the same kind of microbes that we find in lions and tigers that have very meat-rich diets. But they also have abundant communities of anaerobic bacteria, similar to those that ruminants use to break down cellulose.

"However, there's not a lot of cellulose in the ocean, but there is a lot of chitin, which is in the exoskeletons of copepods that baleen whales eat," Girguis continued. "What our paper suggests is the whale foregut is much like a cow's gut, and we posit that chitin-degrading anaerobic microbial community thrives in there, breaking down that material and making it available to the whale."

Those exoskeletons, Girguis said, represent as much as ten percent of whale's total food intake, and would otherwise simply be defecated. By allowing whales to access the nutrition in the chitin-rich material, whales are able to extract the most possible benefit from their diet.

"It's almost like a pre-adaptation," he said "that may give them a differential advantage in harnessing energy from their food. The morphology of their gut comes from their ancestors, the very same ancestors to cows, camels and other ruminants. It serves them well even as carnivores because it allows them to maximally extract nutrition from their food."

Ultimately, Girguis said, the study addresses questions that reach far beyond the guts of whales.

"This is really a question of what we can call phylogenetic inertia," he said. "Because what we're really thinking about is: When you look at the microbiome of an organism, you can -to some degree- look back in time and see its ancestors, because organisms that are related to one another seem to have similar microbiomes.

"But not all organisms that are related live in the same kind of environment," he continued. "So the question is how different does your environment need to be before it changes your microbiome? This is a fundamental question about the relationship between your ancestry versus your current environment."

Many of those questions, however, might not have been asked, Girguis said, were it not for then-undergraduate student Annabel Beichman.

Now a graduate student at UCLA and the second author of the study, Beichman kick-started the study when she and University of Vermont conservation biologist Joe Roman took on the unenviable task of following pods of right whales at sea and collecting samples of their feces to determine which microbes were present.

"There's no other way to get the fecal samples but to collect them from the ocean," Roman said.

"It was a thrill to set out each morning into uncertain weather to search for elusive right whales, then to extract and sequence DNA from our smelly trophies," Beichman said. "It had always been my passion to use the latest advances in genetic sequencing technology to answer questions about species of conservation concern, and so I wanted to add a genetic component to the study.

"Working with my advisors to conceive the research questions based on the scientific literature, collect fecal samples in the field, and carry out DNA sequencing and analysis gave me invaluable experience at every stage of the study," she added. "We all had different theories as to what the whale gut community might look like. What none of us expected was to see so much divergence from terrestrial mammals, or these shared characteristics with both terrestrial carnivores' and herbivores' microbiomes."

"Given what we know about whales' ancestry - that they're related to ruminants, and that they still have a multi-chambered foregut - there were several things we might find," Girguis said. "One hypothesis was that their microbiome would look like those of other meat-eaters like lions and tigers, and the foregut was just vestigial. The other hypothesis was that it allowed a different group of microbes to do something we hadn't thought about. What we found was that whales have a microbiome that looks halfway like a ruminant and halfway like a carnivore."

"We've come to better understand the evolution of whales over the past few decades, and see where they fit on the evolutionary tree. But we have not understood the microbial changes that have allowed them to become one of the most successful groups of animals in the ocean," said Roman. "This study helps explain that."

Going forward, Girguis and colleagues hope to sample the microbial community in whales' stomach chambers, and to extend the study to toothed whales, which don't have such chitin-rich diets.

The team has also received interest from aquariums, which may be able to use information about the gut microbes in whales in order to better care for animals kept in captivity.

"A lot of aquariums...they know when their whales are healthy or not, but they don't always have a causal factor, and these gut microbes may be a big clue," Girguis said. "As long as people keep whales in captivity, there is value in this type of research, because it can keep them as healthy as possible."

While it may not provide a definitive answer to questions of phylogenetic inertia, the study does suggest that some morphological features, if they can provide an advantage, are retained, despite dramatic changes in a creature's environment.

"We now have this snapshot that addresses this question of how a creature's evolutionary past interacts with its microbiome, and how their diet today influences their microbiome," he said. "The answer is...if that morphological feature, if it has value to a species, then it may well be something that's capitalized on over evolutionary time."


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


.


Related Links
Harvard University
Follow the Whaling Debate






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





WHALES AHOY
Season's first dolphins killed in annual Japan hunt
Tokyo (AFP) Sept 11, 2015
Japanese fishermen on Friday killed the first dolphins of the season in a controversial annual hunt that attracted global attention after it was featured in the Oscar-winning 2009 documentary "The Cove". An official with the local fishing union in the small town of Taiji said boats left early Friday morning and trapped a dozen dolphins. "They have already been killed," he added. Duri ... read more


WHALES AHOY
Nepal quake survivors turn porters to deliver aid

Hungarian army given sweeping powers against migrants

Over 190 hurt when fire drill goes wrong in China

Iraqis buy life jackets for trip to Europe's distant shores

WHALES AHOY
'Lab-on-a-Chip' to cut costs of sophisticated tests for diseases and disorders

Physicists defy conventional wisdom to identify ferroelectric material

Engineers unlock remarkable 3-D vision from ordinary digital camera technology

Making 3-D objects disappear

WHALES AHOY
Taiwan boat caught with huge illegal shark fin haul

Omega-3's are vital for a healthy ocean

Acidic ocean will bend the mermaid's wineglass

The saying 'It never rains but it pours' is truer than ever in Scotland

WHALES AHOY
Melting Arctic sea ice accelerates methane emissions

Adaptation to high-fat diet, cold had profound effect on Inuit, including shorter height

Arctic sea ice summertime minimum is fourth lowest on record

Solving the problem of sea ice thickness distribution using molecular concepts

WHALES AHOY
Fearless fowl grow and lay better

Activist against palm oil shot dead in Guatemala

Land degradation costs trillions of dollars

Hunter-gatherers were enjoying oatmeal 30,000 years ago

WHALES AHOY
At least 10 killed in Iran flash flooding: state TV

Several dead as severe floods hit Sierra Leone capital

Lessons from 2010 quake saved lives in Chile: experts

Tropical storm Ida gains strength in the Atlantic: forecasters

WHALES AHOY
Burkina Faso army chiefs, France order coup leaders to disarm

Dealing with climate change and local beliefs in Africa

Burkina on the brink amid coup led by ex-dictator's ally

Shots fired as Burkina Faso guards seize president, PM

WHALES AHOY
Scientists report earlier date of shift in human ancestors' diet

Fossil trove adds a new limb to human family tree

Bonobos use finger-pointing, hand gestures to communicate

Ancient human shoulders reveal links to ape ancestors




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.