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New study measures how much of corals’ nutrition comes from hunting

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When it comes to feeding, corals have a few tricks up their sleeve. Most of their nutrients come from microscopic algae living inside of them, but if those algae aren’t creating enough sustenance, corals can use their tentacles to grab and eat tiny prey swimming nearby.

A new study from researchers at the Woods Hole Oceanographic Institution (WHOI), the University of New Mexico, and Scripps Institution of Oceanography is revealing that more of corals’ nutrients come from this sort of hunting than previously expected, information that may help predict the fate of coral reefs as global ocean temperatures rise. The study published Sept. 17, 2019, in the journal Functional Ecology.

When you have a heat wave, corals start bleaching. Symbiotic algae, which live inside corals and provide them with most of their nutrients, are expelled from their body. If corals stay bleached for too long they basically starve to death,” says Michael Fox, a postdoctoral scholar at WHOI and lead author on the paper. “But if a coral has the opportunity to eat a lot before it bleaches or while it is bleached, it can survive off its fat stores long enough to regain those symbionts when water temperatures cool off. If we can better understand when, where, or why corals are eating, we may be able to understand why they survive better in some places than others during future bleaching events.”

Corals

Michael Fox, WHOI postdoctoral scholar and lead author of the study, sampling coral on Pulo Anna Island, Palau. Photo courtesy of Brian Zgliczynski

Fox and his colleagues conducted their study from samples they collected at Palmyra Atoll, a remote US national wildlife refuge in the central Pacific Ocean. After bringing them back into the lab, the researchers removed the coral polyps from their skeletons, and then separated the coral animals and their symbiotic algae in a centrifuge. The team then extracted essential amino acids from the corals, their symbionts, and the tiny zooplankton that corals often eat.

Essential amino acids are required for an animal to survive, but most corals can’t make them. They have to get them from either their symbionts or something they just ate,” says Fox. “But each of those sources make amino acids in different ways, which gives the molecules distinct chemical signatures.”

Those signatures can be used to “fingerprint” the source of the amino acid, he adds. By measuring chemical differences in six individual amino acids, the researchers were able to determine how much of a coral’s nutrition was coming from symbionts, or from captured prey. This new method for measuring coral nutrition allows scientists to estimate the contributions of different food sources to coral diets, providing a more accurate view of their nutrition than previous methods. The technique was co-developed by animal ecologist Seth Newsome of the University of New Mexico, who is also a co-author on the study.

To my knowledge, this has never been done with corals before. It really changed our perspective,” says Fox. “Our findings suggest that some corals are eating a lot more than we previously thought, which has big implications for reef survival during climate change.  We’ve also learned that individual corals of the same species can have very different diets—this may be an important source of variation that we’ll have to take into account to understand how corals will respond to future changes.

For more information about the work of the WHOI please visit their website by clicking here.

Marine Life & Conservation

BLUE EARTH – Future Frogmen Podcast Series – Deep-Sea Stories From a Shadow Diver: a conversation with Richie Kohler

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A series of conservation educational podcasts from Future Frogmen, introduced by Jeff Goodman.


Deep Sea Stories From a Shadow Diver: a conversation with Richie Kohler. 

This episode of the Blue Earth Podcast is a conversation with Richie Kohler. He’s an explorer, technical wreck diver, shipwreck historian, filmmaker, and author.

Richie was featured in Robert Kurson’s incredible book “Shadow Divers ”. It’s a thrilling true story about Richie and John Chatterton’s quest to identify the wreck of an unknown WWII German U-boat (submarine), 65 miles off the coast of New Jersey. They dedicated six years of their lives attempting to identify the wreck.

Richie has travelled the world and explored many deep wrecks, including the Andrea Doria, Titanic, and Britannic. He’s the author of “Mystery of The Last Olympian” about the Britannic.


Richard E Hyman Bio

Richard is the Chairman and President of Future Frogmen.

Born from mentoring and love of the ocean, Richard is developing an impactful non-profit organization. His memoir, FROGMEN, details expeditions aboard Jacques-Yves Cousteau’s famed ship Calypso.

Future Frogmen, Inc. is a nonprofit organization and public charity that works to improve ocean health by deepening the connection between people and nature. They foster ocean ambassadors and future leaders to protect the ocean by accomplishing five objectives.


You can find more episodes and information at www.futurefrogmen.org and on most social platforms @futurefrogmen.

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Marine Life & Conservation

New Fisheries Act misses the mark on sustainability, but what now?

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A better future for our seas is still beyond the horizon, says Marine Conservation Society

The UK’s landmark post-Brexit fisheries legislation has now become law. The Fisheries Act, the first legislation of its kind in nearly 40 years, will shape how the UK’s seas are fished for years to come.

The Marine Conservation Society, which campaigned for amendments to the legislation throughout its development, is disappointed by the removal of key sustainability amendments and by the removal of a commitment to rolling out Remote Electronic Monitoring.

The charity has committed to pushing the UK Government to go further than the framework which the Fisheries Act sets out, with greater ambition for the state of UK seas.

Sandy Luk, Chief Executive of the Marine Conservation Society said: “UK Government and devolved administrations must act urgently to deliver climate and nature smart fisheries under the new Fisheries Act. This is a key condition if our seas are to recover to good health. The UK Government removed key amendments from the legislation while making promises on sustainability and the introduction of remote electronic monitoring. We will continue to hold the government to account over these promises.”

“I’m pleased to see the recognition of the important role fisheries play in our fight against the climate emergency.  However, even with a climate change objective in the Act, actions speak louder than words. We must get to work delivering sustainable fisheries management, which will have a huge benefit to our seas, wildlife and the communities which depend upon them.”

The Fisheries Act has become law against a backdrop of the ocean’s declining health. UK waters are currently failing to meet 11 out of 15 indicators of good ocean health and over a third of fish in UK waters are being caught at levels which cannot continue into the future. Whilst the legislation failed to address some of the more pressing issues facing UK seas, including overfishing, there is still an opportunity to affect change in the years which follow.

Sam Stone, Head of Fisheries at the Marine Conservation Society said: “The Fisheries Act marks the start of a new era of fisheries management in the UK, but the next two years will be critical in defining what this looks like. The new Act has some good objectives, but we now need to come together to make sure it really delivers the on-water change that is desperately needed for ocean recovery.

“There is genuine opportunity to create fisheries that deliver for coastal communities and for the environment, but it means moving away from ‘business-as-usual’. The UK and devolved governments now have the powers to move forward with progressive new management in their waters. That means proper incentives for low impact fishing, proper monitoring of catches and proper commitments to sustainable fishing.

“In the short term, the four nations must work together to make impactful changes, starting by addressing the UK’s most at risk fish stocks. Recovery plans are needed for our depleted stocks, including new catch limits, selectivity and avoidance measures, protection of vital habitats and fully documented catches. Rolling out Remote Electronic Monitoring with cameras on larger vessels throughout the UK should be top of the agenda if future policy is to be as well informed as possible.”

For more information about the Fisheries Bill and the Marine Conservation Society’s work, visit the charity’s website.

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