Weekly round-up: December 6

Loggerhead sea turtle eggs incubated in warmer temperatures have a lower chance of hatching, while hatchlings are also less likely to survive their journey from nest to sea.

Researchers investigating the effects of sand temperature on loggerhead nests in Cabo Verde, the only rookery of the species in the eastern Atlantic, found nests buried in dark sand, which absorbs more heat, had a higher incidence of female hatchlings than those in light sand – but that the warm treatment resulted in 33 per cent more failed embryos.

A loggerhead turtle hatchling (Dionysisa303)

In addition, hatchlings emerging from the warmer nests were smaller and weaker, thus more likely to be caught by ghost crabs on their way to the sea. The higher mortality cancelled out the benefits of a higher proportion of females.

The findings raise considerations for conservationists and their efforts to help sea turtles adapt to climate change.
Publication Climatic Change

A new species of comb jelly has been identified in the deep sea off the coast of Puerto Rico – using only high-definition footage from a remotely-operated vehicle.

The new species, Duobrachium sparksae, has the shape – and movement – similar to that of a hot air ballon, but with tentacles emerging from two ‘arms’. Like most comb jellies – which are not related to jellyfish – it has eight rows of cilia that refract light into bright colours as they pulse. Duobrachium sparksae is a carnivore, eating small arthropods and larvae.

Duobrachium sparksae

A National Oceanic and Atmospheric Administration (NOAA) Fisheries team discovered three individuals during a 2015 dive in the Guajataca Canyon, deploying the remotely operated vehicle Deep Discoverer.

Researcher Allen Collins said: “It’s unique because we were able to describe a new species based entirely on high-definition video. The cameras on the Deep Discoverer robot are able to get high-resolution images and measure structures less than a millimeter. We don’t have the same microscopes as we would in a lab, but the video can give us enough information to understand the morphology in detail, such as the location of their reproductive parts and other aspects.” 

Watch a video of the new comb jelly here.
Publication Plankton and Benthos Research

Eurasian beavers (Ray Scott)

Nine months after their release, Eurasian beavers have built what is thought to be the first dam on Exmoor in four centuries.

The beavers, a male and female pair, were released on the Holnicote estate in January as part of efforts to manage flooding and improve biodiversity. Their first dam was completed in October, and has created an ‘instant wetland’ according to the National Trust.

Ben Eardley, project manager at the National Trust, said: “It might look modest, but this beaver dam is incredibly special – it’s the first to appear on Exmoor for almost half a millennium and marks a step change in how we manage the landscape. 

The beavers’ new dam on Holnicote estate

“What’s amazing is that it’s only been here a few weeks but has created an instant wetland. We’ve already spotted kingfishers at the site, and over time, as the beavers extend their network of dams and pools, we should see increased opportunities for other wildlife, including amphibians, insects, bats and birds.”

Beavers are often referred to as ecosystem engineers – while the dams they build provide deep pools which the animals themselves use for shelter and food, they enhance habitats for myriad other wildlife, and also help to prevent flooding by slowing, storing and filtering water.
Source National Trust

UN secretary general Antonio Guterres has said humanity is “waging a war on nature” in a speech titled “The State of the Planet”, describing the fight against climate change as the top priority of this century.

“Biodiversity is collapsing. One million species are at risk of extinction. Ecosystems are disappearing before our eyes. Deserts are spreading. Wetlands are being lost. Every year, we lose ten million hectares of forests. Oceans are overfished – and choking with plastic waste. The carbon dioxide they absorb is acidifying the seas. Coral reefs are bleached and dying.”

Speaking at the Columbia University in New York, Guterres added that “nature always strikes back – and it is already doing so with growing force and fury”.

“Apocalyptic fires and floods, cyclones and hurricanes are increasingly the new normal,” he said. “The North Atlantic hurricane season has seen 30 storms, more than double the long-term average and breaking the record for a full season.”

However, he said now was time to “flick the green switch” in order to protect both the planet and its most vulnerable communities.

“We have a chance to not simply reset the world economy, but to transform it.

“A sustainable economy driven by renewable energies will create new jobs, cleaner infrastructure and a resilient future. An inclusive world will help ensure that people can enjoy better health and the full respect of their human rights, and live with dignity on a healthy planet.”
Source UN News

The Great Barrier Reef (Ayanadak123)

The conservation status of the Great Barrier Reef and the Islands and Protected Areas of the Gulf of California has been reclassified as critical by the International Union for the Conservation of Nature. Critical sites are “severely threatened and require urgent, additional and large-scale conservation measures”. 

Reporting in IUCN World Heritage Outlook 3, the organisation assesses the status of all 252 natural and mixed (cultural and natural) World Heritage sites. Since the last report in 2017, only eight sites have improved while 16 have deteriorated.

The Great Barrier Reef and the Islands and Protected Areas of the Gulf of California bring the critical list to 18 – one site, Mexico’s Monarch Butterfly Biosphere Reserve, was upgraded from critical to significant concern.

Climate change and its effects – including coral bleaching, severe weather events and droughts – were ranked as the most common threat across World Heritage sites, followed by invasive alien species.
Source IUCN

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