Science Briefs: Logging threatens breeding turtles

Logging threatens breeding turtles

Turtle breeding sites are already suffering from the impact of tourism and fishing, but scientists have just discovered that rare leatherback turtles nesting on the shores of Colombia in South America are also being threatened by logging in tropical forests.

Logging debris is hindering the movements of both the hatchlings and their mothers at one of the world's most important nesting sites, said researchers at the University of Exeter in Britain and the Donana Biological Station in Spain, who published their findings in the journal Marine Ecology Progress Series.

To nest and breed successfully, females must be able to cross the sandy beaches to dig their nest to successfully incubate their eggs.

In turn, hatchlings must be able to cross the sand unaccompanied to reach the water.

The team monitored 216 turtles, studying how their activity varied with the amount of debris. They found that females which nested in areas with higher amounts of debris spent more time building their nest and tended to do so closer to the shoreline. This meant they were more vulnerable to flooding, which puts their eggs at risk. Some females were even wounded while negotiating the debris.

The debris also meant it took longer for hatchlings to reach the sea, increasing their chance of being eaten by predators.

Professor Brendan Godley, the co-author and director of the Centre for Ecology and Conservation at the University of Exeter, said in a statement that leatherback turtles are already under immense pressure, not only from being caught in fishing nets but also from ingesting marine plastic litter. "It is now paramount that beach clean-up operations are built into logging activities to prevent further damage to this species," he said.

Dr Adolfo Marco Llorente, from the Donana Biological Station, added: "This is on a scale that could lead over time to reduction of the overall population. Simple measures could make a real difference, such as repositioning organic waste areas, or salvaging the wood debris as an energy source."

He also called for improvement in logging practices to reduce its impact on the marine environment.

Grey hair linked to heart disease

Scientists in Egypt have linked grey hair to an increased risk of heart disease in men.

At a conference organised by the European Society of Cardiology last week, Dr Irini Samuel of Cairo University reported that whiter hair was associated with increased risk of coronary artery disease, regardless of a person's actual age.

Conversely, patients with coronary artery disease had whiter hair than those without coronary artery disease.

The study looked at 545 adult men who underwent multi-slice computed tomography coronary angiography for suspected coronary artery disease.

The greyness of their hair was recorded using a hair whitening score, which has five levels ranging from pure black to half-half to pure white. Each patient's score was determined by two independent observers.

Dr Samuel explained that this could be because atherosclerosis and hair greying share similar causes, such as impaired DNA repair, oxidative stress, inflammation and hormonal changes.

"Atherosclerosis and hair greying occur through similar biological pathways and the incidence of both increases with age," she said. "Our findings suggest that, irrespective of chronological age, hair greying indicates biological age and could be a warning sign of increased cardiovascular risk."

Dr Samuel said high-risk patients should have regular check-ups and get preventive treatment. Meanwhile, more research is needed to learn more about the genetic and environmental factors in hair whitening, and to extend the study to women.

She added that if the findings are confirmed, the extent of hair greying could be used as an indicator for risk of coronary artery disease.

Leaf holds key to better battery life

The natural structure found within leaves could improve the performance of everything from rechargeable batteries to high-performance gas sensors.

Researchers from China, Britain, the United States and Belgium have designed a material with a network of pores resembling the highly branched veins of a leaf, which could make energy transfers more efficient. The breathing system of insects branches in a similar way to maximise the delivery of oxygen.

The material could improve the performance of rechargeable batteries by optimising the charge and discharge process and relieving stresses within the battery electrodes that limit their life span.

The scientists used zinc oxide nanoparticles and a process of solvent evaporation to create the material with the pores.

Co-author Tawfique Hasan, from the University of Cambridge, said: "The process is incredibly simple and is entirely driven by the nanoparticle self-assembly. Large-scale manufacturability of this porous material is possible, making it an exciting, enabling technology, with potential impact across many applications."

The researchers also showed that the material improved the long-term stability and charge-and-discharge speed of lithium-ion storage, with up to 25 times greater capacity compared to the graphite material currently used in lithium-ion battery electrodes.

Compiled by Lin Yangchen

A version of this article appeared in the print edition of The Straits Times on April 14, 2017, with the headline 'Science Briefs'. Print Edition | Subscribe