Rolex Sydney Hobart yacht race 2024 preview

 

From SailWeb

 

105 Yachts are set to compete in the 79th Rolex Sydney Hobart Yacht Race starting Boxing Day 26 December on Sydney Harbour.

 

 Relentless waves and squalls at the Organ Pipes

2023 Rolex Sydney Hobart Yacht Rac

photo © Rolex / Kurt Arrigo

This year’s race will feature 23 Double Handed entries, showcasing the growing popularity of this demanding discipline, alongside four 100-foot maxis who will be fighting for the Line Honours victory.
 

Local spectators can look forward to a thrilling display of competitive sailing as the fleet navigates to the Heads and sets a course for Tasmania, tackling one of the world’s most challenging offshore races.
 

Launched in 1945, the Rolex Sydney Hobart Yacht Race has built an towering global reputation to become one of the most famous fixtures on the international sporting calendar.

The 2024 marks the 79th edition of the 628-nautical mile (1,163 kilometre) offshore race from Sydney Harbour to Hobart, the state capital of Tasmania.

 

Starting on its traditional slot on 26 December, an impressive fleet of over 100 yachts are expected to participate.

 

 Kurt Arrigo Photography

 

Rolex has partnered the event and its organizer, the Cruising Yacht Club of Australia (CYCA), since 2002, the race forming an integral part of the Swiss watchmaker’s long-standing support for yachting.
Stay tuned for more exciting updates for this great race!

Links :

• Rolex Sydney Hobart Yachts
• Sail World : Sydney Hobart – Tasman Island in 20 hours

Plastic in the ocean and on our plates: What are the risks to human health?

Plastic that enters the marine food chain can end up on our plates.

TravisYewell/Unsplash

From The Conversation by Amélie Châtel

It’s no secret: when we savour a delicious piece of fish or a platter of seafood, we’re not just consuming valuable omega-3s and vitamin D. Alongside these benefits come less appetising elements — countless micro- and nano-plastics.

 

A sampling of the freshwater invertebrates C. fluminea in the Loire river. 

Amélie Châtel

These plastic particles, measuring less than 5 millimetres, enter our oceans through human waste and penetrate the food chain. 

According to an Ifremer study, around 24,400 billion microplastics are floating on the ocean’s surface. These particles are found in all marine organisms — from microalgae to fish, which occupy higher levels of the food chain. 

This phenomenon not only threatens marine ecosystems but also raises concerns about potential risks to human health.

What exactly do we know about the accumulation of these pollutants in marine life and the dangers they pose to human health?

 

 

Marine organisms bioaccumulate micro- and nano-plastics that humans discharge into the sea.  

Naja Bertolt Jensen/Unsplash, CC BY-NC-SA

 
Micro- and nano-plastics: an invisible threat

Since the 1950s, plastic production has grown exponentially, reaching 58 million tonnes in Europe in 2022 alone. 

This has led to massive amounts of waste.

Over time, wind, waves, sunlight and microorganisms break down larger plastic waste into microplastics (1–5 mm) and nanoplastics (smaller than 100 nanometers), which now contaminate all parts of the environment, including the air, soil and water.

The process by which these plastics accumulate in organisms across different levels of the food chain is known as “bioaccumulation”.

 

A design experiment from May 2022 » : laboratory exposures of C. fluminea bivalves to microplastics. Alice Vidal

Research from our laboratory reveals that in aquatic environments, micro- and nano-plastics are ingested by a wide range of species — from microalgae at the base of the food chain to top predators like eels.

The impact on marine life

These ingestions have serious consequences. Studies show that microplastics can cause toxic effects in marine animals.

For instance, in mussels, microplastics can block digestive systems, activate immune responses, cause DNA damage and interfere with the expression of genes essential to various cellular functions.

The severity of these effects depends on the plastics’ size, composition, degree of degradation and any harmful chemical additives they may contain.

Plastics often contain high levels of phthalates, which are endocrine disruptors.

These chemicals can interfere with hormonal systems, posing risks not just to marine life but potentially to humans as well.

Risks to human health

Plastics ingested by marine animals inevitably make their way into our food supply.

 

Plastic macro-waste collected at Montjean sur Loire. Amélie Châtel, Fourni par l'auteur

Frequent seafood consumers are estimated to ingest thousands of microplastic particles annually. Although research on the precise health effects on humans is ongoing, some troubling hypotheses have emerged.

Once inside the human body, these particles may cause damage similar to that observed in fish.

Studies on human cells indicate that micro- and nano-plastics can disrupt cellular functions in ways akin to the effects seen in marine organisms.

Scientists are particularly concerned about the toxic impacts of plastic additives.

Additionally, micro- and nano-plastics can act as carriers for pathogens or bacteria, potentially increasing the risk of infectious diseases.

The urgency to tackle plastic bioaccumulation in the food chain cannot be overstated.

By taking swift action to limit plastic usage and improve recycling technologies, we can slow the progression of this environmental and health crisis.

 

Links :

• GeoogleMapsMania : Drowning in plastic

Airlines, shipping companies and sleigh drivers rush to update crucial navigation systems ahead of Christmas rush

Magnetic declination (the angle between magnetic and geographic north) in 2025 according to WMM2025.

Red is magnetic north to east of geographic north; blue is to west. 

BGS © UKRI and © Wessel, P., and W. H. F. Smith (1996), A global, self-consistent, hierarchical, high-resolution shoreline database, J. Geophys. Res., 101(B4), 8741–8743, doi:10.1029/96JB00104 (v2.3.6)

 

From BGS 

 

Release of major upgrade to a new model tracking magnetic north prompts global reset of satellite tracking systems across trade and passenger transport routes.

 

Hundreds of thousands of mariners, airline operators and North Pole-based gift distribution specialists will be rushing to update their navigation systems after the launch of a new model tracking magnetic north, which is crucial to the accuracy of global positioning systems (GPS) that are relied upon across the world.

In partnership with the UK Defence Geographic Centre and the US National Geospatial-Intelligence Agency (NGA), BGS and the US National Oceanic and Atmospheric Administration (NOAA) have teamed up to update the World Magnetic Model (WMM).

 

 

 

The WMM is the standard model used by the United Kingdom and the United States governments, including the U.S. Federal Aviation Administration and the U.S. Department of Defense, as well as organizations with an international remit such as the North Atlantic Treaty Organization (NATO), the International Hydrographic Organization and the UK Hydrographic Office.

The model comprises a series of magnetic field maps that track changes in the magnetic field, such as the spot at which compass needles point in the northern hemisphere.

To ensure pinpoint accuracy, it is crucial that the shifts in magnetic north, which are caused by flow of the liquid iron in the outer core of the Earth, are taken into account in the electronic equipment that is trusted to guide global trade and enable the safe transit of travellers across the planet.

 

From GPS-enabled mobile phones to nuclear submarines, this improved resolution update will allow navigation with more accuracy than ever before to take place in the run up to Christmas — vital for all those who do not have a red nose to follow.

The WMM is officially released today, ensuring users can have the most up-to-date information so they can continue to navigate accurately for the next five years.
The current behaviour of magnetic north is something that we have never observed before. Magnetic north has been moving slowly around Canada since the 1500s but, in the past 20 years, it accelerated towards Siberia, increasing in speed every year until about five years ago, when it suddenly decelerated from 50 to 35 km per year, which is the biggest deceleration in speed we’ve ever seen.
Dr William Brown, global geomagnetic field modeller at BGS.

While each model predicts how magnetic north will shift over the five-year period to limit any error, the change will have an impact on travellers.

 

Magnetic north pole locations from 1590 to 2030. BGS © UKRI and © Wessel, P., and W. H. F. Smith (1996), A global, self-consistent, hierarchical, high-resolution shoreline database, J. Geophys. Res., 101(B4), 8741–8743, doi:10.1029/96JB00104. (v2.3.6).

Imagine someone was planning to travel by sleigh from a chimney top in South Africa to a snow covered-roof in the UK, a journey of around 8500 km. Using the previous WMM and setting off just one degree off-course, he would end up approximately 150 km away from where he should[1].

With a margin of error of only a few inches between chimney flues, this could cause significant issues.
Values from the updated model can now be calculated, and the WMMHR2025 and the WMM2025 are available for download.

 

Links :

• BGS : WMM 2025
• NOAA : WMM 2025
  
• GeoGarage blog : Earth’s magnetic North Pole moving closer to Russia: implications and insights
•  / World Magnetic Model updated / World Magnetic Model 2020

Chido tropical cyclone over Mayotte

🔴⚠️🌀🇲🇿This impressive view of #Landsat 9 on Dec.14, showing the 20km-large eye of Cat.4 #Chido over #Mayotte, explains the total devastation caused by the strongest #TropicalCyclone to hit the islands in the last 90 years,,fearing several hundreds deaths. #Climatemergency pic.twitter.com/my9lqCYXQK

— SatWorld (@or_bit_eye) December 16, 2024

Links :

• WMO : Tropical cyclone Chido devastates Mayotte in Indian Ocean

Sea lions with video cameras help scientists map ocean floor

Australian sea lion by John Turnbull via Flickr (CC BY-NC-SA 2.0).

 

From Mongabay by Shreya Dasgupta 

 

For the first time ever, scientists have had help from sea lions in mapping the ocean floor.
And the marine mammals have done their job well, capturing six different marine habitats, including algal meadows and reefs, that make up South Australia’s seabed, researchers report in a recently published study. 

 

For much of the planet’s ocean, what the seafloor looks like is still a mystery.

Conventional surveys using specialized underwater equipment and vessels require large crews as well as good weather, which makes mapping wide areas challenging and expensive, Nathan Angelakis, lead author of the study and a doctoral student at the University of Adelaide, Australia, told Mongabay in an email.

As an alternative, the researchers fit small, lightweight video cameras and movement trackers on eight adult female Australian sea lions (Neophoca cinerea).

The team had two goals: to understand the habitats and food that are critical for the endangered species, and to map the little-known seafloor off southern Australia’s coast. 

 Sea lion swimming through invertebrate reef, sponge garden, macroalgae reef, bare sand, and invertebrate boulder habitats.
Video: Angelakis et al. 2024. 

 The sea lion videographers ended up capturing more than 89 hours of data and footage, recording around 560 kilometers (350 miles) of the continental shelf, at depths of 5-110 meters (16-360 feet).

 

On reviewing this data, the scientists saw that the sea lions eat a wide variety of fish, small sharks, stingrays and octopuses, either by flipping rocks over, digging up sand, or ambushing schools of fish.
“We were also lucky enough to capture footage of a mother taking her pup on a trip to sea, providing the first direct evidence we have that Australian sea lion mothers pass on their foraging skills to pups,” Angelakis said.

 

The team also identified six kinds of seabed habitats from the videos.
They combined this habitat data at different locations, with long-term oceanographic and environmental data for those locations, to then predict habitats for areas that the sea lions didn’t visit.
“This allowed us to map and predict habitats on the seabed for more than 5,000 square km [1,930 square miles] of previously unexplored seabed across the continental shelf in southern Australia,” Angelakis said.

 

Katie Dunkley, a marine researcher at the University of Cambridge, U.K., who wasn’t involved in the study, told The Washington Post that while the number of sea lions used in the study was small, the study was a “proof of concept” showing that sea lions can help us map the ocean floor. 

Angelakis added that such baseline knowledge of seabed habitats and the conditions that influence their distribution is crucial “for understanding how they may be impacted by human activity.” 

Furthermore, the study improves our understanding of the marine habitats that are crucial for the rapidly declining Australian sea lions, he said. 

“This information is fundamental for better conserving and managing their populations in the future,” Angelakis added.