Academy Of Diving UK

18/08/2023

ACADEMY OF DIVING UK: WEATHER PATTERNS: La Niña is finishing an extremely unusual three-year cycle – here’s how it affected weather around the world

26th August 2023. El Niño and La Niña events and how this impacts weather around the world.
It was anchovy fishermen in Peru who first noticed and named El Niño events in the tropical Pacific hundreds of years ago. Their catches would fluctuate and the largest declines were seen near Christmas when the ocean was at its warmest – they called it El Niño de Navidad, the boy of Christmas.
With a larger network of observations and some inspired statistical analysis, it became apparent that this decline in fish stocks was part of a Pacific-wide phenomenon including changes in the ocean and atmosphere. This was ENSO, the El Niño-Southern Oscillation.
As part of this analysis it became clear that during El Niño events the Pacific was typically warmer than usual in the east, colder in the west, and the trade winds blowing from east to west were weaker. What also became clear was that there were other times when the winds were stronger and the east was colder and the west was warmer. These periods were named La Niña – the girl – in a nod to their opposite characteristics to El Niño.
El Niño or La Niña conditions typically last for around nine months, beginning in June, peaking in December, before dissipating by April. Historically, La Niña events have been smaller and less noted – the change in the anchovy catches is not as notable as the collapse seen in El Niños so was never remarkable to the Peruvian fishermen. However, for a number of reasons, La Niña is becoming a more noted phenomenon.
During La Niña events, global temperatures tend to be colder and this can explain some of the downward bumps on the otherwise inexorable rise of global temperatures. Last year, 2022, was the third consecutive La Niña year, which is highly unusual and has only occurred three times since reliable records began in the 1950s. Outside of the tropical Pacific, the effects of La Niña can be just as marked and just as devastating as those of El Niño, which is likely to return in late 2023.

In general, the warmest year of any decade will be an El Niño year, the coldest a La Niña one. NOAA / climate.gov
How changes in the tropical Pacific affect the rest of the world

Climate scientists have been aware of how changes in the atmosphere in one location can be linked to another for many years. These links are termed “teleconnections”. Perhaps the first example of a teleconnection was described in the 1920s by the physicist Gilbert Walker who noticed that changes in atmospheric pressure in Darwin, on the north coast of Australia, and Tahiti, 8,000kms away in the middle of the Pacific, were linked through, what he termed, the Southern Oscillation. This observation ultimately led to the description of the El Niño/La Niña phenomenon.
Teleconnection patterns have now been noticed in all regions of the globe. In northern Europe the most well known is the North Atlantic Oscillation, which describes a link between air pressure in a particular area over Iceland and one over the central North Atlantic near to the Azores. Changes can then be linked to changes in the weather over northern Europe and the UK.
These teleconnection patterns exist because the global atmosphere behaves like a drum. If you hit a drum in one location the whole surface vibrates and the note that the drum sounds depends upon how tight the drum skin is.
In this analogy, heating in the tropical atmosphere plays the role of the drum stick and the waves that spread out across the surface are termed Rossby waves. The “note” that these waves play is determined by the structure of the atmosphere, but rather than skin tension it is the winds and rotation of the earth that determine the pitch of the atmosphere.
The strongest teleconnection from the tropical Pacific and La Niña is within the Pacific Basin. For example La Niña events tend to mean wetter winters in the Pacific Northwest of the US.
However, Rossby waves can reach all the way across North America and into the North Atlantic, where they can start to affect the weather by tweaking the high-altitude jet stream which can in turn affect the storms that are responsible for much of the UK’s winter rain.
Because the behaviour of Rossby waves depends upon the winds in the atmosphere, La Niña’s influence on the North Atlantic is not the same in all seasons. In late winter the Rossby waves from La Niña tend to intensify and shift the Atlantic jet stream towards the North Pole, causing more storms to hit the UK and with them increase the rainfall.
It’s harder to directly link the two in early winter, since in this season the Rossby waves interact with winds that are more affected by the climate state of the tropical Atlantic.

The UK is stormier and rainier in late winter during La Niña years
An uncertain future

It’s hard to know exactly what climate change will mean for El Niños and La Niñas. Average sea surface temperature across the Pacific will increase, but that is less important to the generation of these weather patterns than the difference in surface temperature between west and east Pacific about which there is a lot less certainty (in part because the surface temperature in the eastern Pacific is always heavily influenced by the upwelling of deeper colder waters).
Computer programs that model the climate suggest the Pacific’s east-west temperature difference will diminish in future, favouring EL Niños which tends to mean more droughts in Australia and other severe weather across the Pacific and beyond. However, the past two decades of enhanced temperature differences and prolonged La Niña events suggest otherwise. The recent three-year La Niña is therefore very interesting, though it’s too soon to draw any firm conclusions.
Changes in the teleconnections are equally uncertain. Therefore, uncertain changes in the teleconnections on top of uncertain changes in La Niña and El Niño add up to an uncertain outlook for the future. Why governments globally are pushing the narrative of global warming and climate change as a man made phenomenon is fairly obvious . The world economic forum has latched onto what can only be described as a gravy train. Huge investments in wind farms, both onshore and offshore. Solar energy companies creating vast fields of solar panels . Companies such as Tesla and the “innovation” of electric vehicles? Something that was introduced as early as 1897 when the first electric powered vehicle was created but now being lauded as the future. Mankind is creating its own nemesis by the production of billions of tons hazardous waste of which the only way to dispose of is by landfill . All these so called modern green projects of electric vehicles , wind turbines, solar panels and heat pumps, all have a shelf life of around five to seven years. The production process of these “ green “ projects create their own pollution, both in the manufacturing and disposal. The public are being misled on a grand scale by the theory that the reduction of fossil fuels usage can save the planet, totally disregarding the fact that the production of these so called green products creates more pollution than conventional fossil burning equivalents. So without diversifying any further , I go back to my original topic of La Nina’s and El Ninos and just go on to conclude that we cannot change the powers of nature. Our planet has been warming and cooling for billions of years. The UK once attached to mainland Europe. Greenland once adjoined to Canada, Australia to New Zealand. The powers of nature are infinite. We as humans have no influence over our planet our world . We are mere atoms in an ever expanding universe. If only our world leaders were not filled with delusions of grandeur and would not think they can change billions of years of nature, we would all have a better understanding of our planet and it’s evolution. Allan Woods

Science & information for a climate-smart nation

11/02/2023

Academy Of Diving UK Coral Reefs.
What is a reef.
The word “reef” holds different meanings for everyone. To a mariner, the term reef applies to shallowly submerged navigational hazards. To a surfer, a reef is an undersea obstruction that can make waves (and surfboards) break. Scientists generally restrict the definition of a reef to rigid biological constructions.
The Earth's first reef-building organisms were photosynthesizing cyanobacteria living about 3.5 billion years ago. From fossil remains, it is known that a variety of organisms have constructed reefs, including bivalves (clams and oysters), bryozoans (coral-like animals), and sponges. Corals have been found in fossil reefs as old as 500 million years, but corals similar to the modern colonial varieties have constructed reefs only during the last 60 million years.
What is a coral reef?
The hard skeleton of coral is formed by the secretion of calcium carbonate by the polyp. The cup-like skeleton deposited by an individual polyp is called a corallite. Polyps gather food particles with the nematocysts (stinging, venomous cells) in their tentacles, and feed from sugars produced by photosynthesizing zooxanthellae, a type of algae. The coral tissue protects these algae from herbivorous grazers, and the algae in turn use many of the polyps' waste products such as carbon dioxide, nitrogen, and phosphorus.
Corals are animals related to jellyfish and anemones. Solitary and colonial corals catch plankton and suspended food particles with arm-like tentacles, which feed a centrally located mouth. Coral reefs are formed by huge colonies of corals that secrete hard calcareous (aragonite) exoskeletons that give them structural rigidity. These colonial hard corals may form elaborate finger-shaped, branching, or mound-shaped structures, and can create masses of limestone that stretch for tens or even hundreds of miles.
Most hard corals also host symbiotic algae, a long-standing and successful partnership. These algae provide them with an additional food source through photosynthesis.
When corals are stressed, they expel these algal symbionts through a process known as coral bleaching. Corals also face serious risk of diseases; black band, white band, and yellow band diseases have been reported from many localities. Hawaiian corals, however, have been relatively free from disease, but the first case of black band disease was reported in 1994.
How do coral reefs form?
Coral atolls develop from reefs fringing volcanic islands. Reefs fringing volcanic islands build vertically to sea level, forming steep-walled barrier reefs. As a volcanic island subsides, or sinks, with time, the growing reef keeps pace with the rising water level. When the island eventually submerges, the ring-shaped reef forms an atoll with a central lagoon.
Corals have a wide distribution in the world's oceans, but the varieties that form reefs typically are restricted to relatively shallow, warm tropical waters between 30° north and south latitudes. Clean, clear water with the right amount of nutrients is essential to their health. After initial colonization of a hard substrate and given suitable conditions for coral growth, an individual larval “spatfall” gives rise to a colony.
Given enough time, coral colonies become thickets. As coral thickets build upward on the skeletal remains of older colonies, a reef is established. Today, richly diverse coral reefs are found along tropical coastlines, on the margins of volcanic islands, and as isolated coral atolls.
Coral reefs are dynamic, evolving through time into different forms. During his voyages on the HMS Beagle, Charles Darwin first recognized the progressive development of coral reefs on volcanic islands. Volcanic islands subside; that is, they have a tendency to cool, condense, and sink through time. As they subside, tropical coral reefs grow upward along their margins.
The Hawaiian Islands-Emperor Seamounts chain is a classic example of this process. Active volcanic islands are found at the southeast end of the chain. Beyond Kauaʻi, however, islands are subsiding slowly and coral reefs have developed around the volcanic cores of islands. French Frigate Shoals, Midway, and Necker Islands are dominantly coral limestone accumulations, but deep sediment cores have revealed the volcanic origins of these islands.
Why are coral reefs in peril?
The Great Barrier Reef arches over 2000 kilometers along the northeast coast of Australia. The white calcium carbonate that coats the coral reflects light, making the water above the reef appear bright blue from space. This phenomenon allows the reef to be visible in satellite images.
Coral reefs are sensitive indicators of the health of marine environments. Yet coral reefs are in decline in many parts of he world. It is estimated that 30% will be destroyed or seriously degraded in the next ten years.
The causes of reef degradation are many. They are being stressed and killed by a variety of local human activities such as grounding of ships, improperly placed anchorages, destructive fishing practices, such as dynamiting or cyanide poisoning, and simply overfishing, which disrupts the balance of these fragile ecosystems.
Pollution and sediment runoff from land are major causes of stress, and even human activities conducted at great distance through warming and pollution can affect coral sustainability.
As coral reefs become stressed, they also are more susceptible to viral and bacterial infections, such as black, white, and yellow band diseases. It is critically important to better understand the role of natural processes and the impact that human activities may have on coral reef. It is also extremely important that consideration is given to our marine environment when swimming in the tropical seas . Sun creams in particular pose a hazard to corals . If you have ever looked round the edges of a swimming pool where swimmers are using sun lotions , you cannot help but notice the oily residue and sediment that covers the tiles . That same residue gathers on corals and suffocates the organisms within , devastating reefs . Do you really need sun cream while in the water? Likewise if you sail boats, be aware of where you drop anchor. An anchor landing on coral and dragging even one metre can kill twelve metres of coral. It takes thousands of years for coral reefs to form . Years of hard work to lay the foundations of coral farms . All can be wiped out in an instant . Respect our reefs so that our children and children’s children can enjoy. REEF AWARE.

12/05/2022

SCUBA DIVING . THE COMPLETE STORY…The name Jacques-Yves Cousteau is synonymous with the history of scuba diving, and you are forgiven if you’re under the impression that the story started with him.
In 1942, Jacques, along with Emile Gagnan, redesigned a car regulator to function as a demand valve, and a device that provided divers with a supply of compressed air delivered with each inhalation. The two met during World War II where Cousteau was a spy for the French Navy.
That compressed air was stored in a tank, and the diver was, for the first time, untethered for longer than just a few minutes. A design recognizable in today’s kit as the “Aqua-Lung,” and one that made scuba diving far more accessible and fun. BUT THAT IS NOT WHERE IT BEGAN…The history of scuba diving begins with something called a “diving bell,” with references going as far back as 332BC, when Aristotle told of Alexander the Great being lowered into the Mediterranean in one.
Unsurprisingly Leonardo Da Vinci also designed a similar self contained underwater breathing apparatus, comprising of a face mask and reinforced tubes (to withstand water pressure) which led to a bell-shaped float on the surface, allowing the diver access to air.
Fast forward to the century between the years 1550 and 1650, and there are far more reliable reports of the successful use of diving bells. Necessity is the mother of invention, and sunken vessels laden with riches provided more than enough incentive for underwater exploration. And, where once the obstacle of potential drowning would have thwarted such ambition, the diving bell was the solution.
Here’s how it worked: the bell would capture the air on the surface, and, when pushed straight down, would force that air to the top and trap it, allowing a diver to breathe a limited store. (The idea is the same as the simple experiment of turning a drinking glass upside down and submerging it directly down into a body of water.)
They were designed purely as a diver refuge that allowed them to stick their heads in and refill their lungs, before heading back out to locate and retrieve whatever sunken b***y they could get their hands on.
The Santa Margarita, a Spanish ship that sank during a hurricane in 1622, and the Mary Rose , a warship of Henry VIII’s English Tudor navy, sunk in battle in 1545, were dived in this way, and some of their treasures recovered. But it wouldn’t be until the creation of 1980s technology that their recoveries would be completed. MAJOR ADVANCEMENTS In the year 1650, a German man named Otto von Guericke invented the first air pump, a creation that would pave the way for Irish born Robert Boyle and his experiments which formed the basis of decompression theory.
In case you need a refresher, this is the bit of scientific theory that states that the “pressure and volume or density of a gas are inversely proportional.” Meaning a balloon full of gas at the surface will reduce in volume, and the gas inside will become denser, the deeper the balloon is taken. For further information read my article on diving decompression. (For divers, this is why air in your buoyancy control device expands as you ascend, but it is also why your tissues absorb more nitrogen the deeper that you go.)
In 1691, scientist Edmund Halley patented a diving bell. His initial design, when descended by cables into the water, acted as an air bubble for the person inside the chamber. Using a levy system, smaller chambers with fresh air were brought down and the air was piped into the bigger bell. With time, he advanced to air pipes leading to the surface to replenish fresh air.
Though models were improved, it wasn’t until nearly 200 years later that Henry Fluess created the first self-contained breathing unit. The unit was composed of a rubber mask connected to a breathing bag and carbon dioxide was exhaled into one of two tanks on the divers back and absorbed by caustic potash, or potassium hydroxide. Though the device enabled considerable bottom time, depth was limited and the unit posed a high risk of oxygen toxicity to the diver.
A closed circuit, recycled oxygen device was developed in 1876 by Henry Fleuss. The English inventor originally intended the device to be used in the repair of a flooded ships chamber. Henry Fleuss was killed when he decided to use the device for a 30 foot deep underwater dive. What was the cause of death? The pure oxygen contained within his device. Oxygen becomes a toxic element to humans when under pressure.
Soon before the closed circuit oxygen rebreather was invented, the rigid diving suit was developed by Benoît Rouquayrol and Auguste Denayrouze. The suit weighed about 200 pounds and offered a safer air supply. Closed circuit equipment was more easily adapted to scuba in the absence of reliable, portable, and economical high pressure gas storage vessels. Robert Boyle first observed a bubble in the eye of a distressed viper used in compression experiments, but it wasn’t until 1878 that a man named Paul Bert linked the formation of nitrogen bubbles to decompression sickness, suggesting that slower ascents out of the water would help the body eliminate nitrogen safely.
Paul Bert also demonstrated that the pain from decompression sickness can be relieved by recompression, which provided a huge step forward in understanding the still perplexing diving illness.
Even though diving science had only just started to grapple with decompression theory in 1878, some 55 years earlier, brothers Charles and John Dean created the first scuba diving helmet by modifying their previously invented self contained underwater breathing apparatus used for fighting fires, called a smoke helmet. The design was supplied with air by a pump at the surface, and would be the start of what we recognize as a “hard hat diver kit” today.
Although it had its limitations (like water entering the suit unless the diver constantly stayed in a vertical position), the helmet was used successfully in salvage during 1834 and 1835. And in 1837, a German-born inventor called Augustus Siebe took the Dean brothers’ helmet a step further, connecting it to a watertight suit that contained air pumped from the surface — establishing even further the basis for suits still in use in the 21st century. This is known as Surface supplied diving. This is diving using equipment supplied with breathing gas using a diver’s umbilical from the surface, either from the shore or from a diving support vessel, sometimes indirectly via a diving bell.
In 1839, the UK’s Royal Engineers adopted this suit and helmet configuration, and, with air supply from the surface, salvaged the HMS Royal George, an English navy vessel that sank in 1782.
The gunship was buried under 20 meters (65ft) of water, and the divers were noted to complain of rheumatism and cold-like symptoms after resurfacing , something which would be recognized today as symptoms of decompression sickness. Thinking back, it’s amazing to consider that for over 50 years , divers were working underwater with no real understanding of how and why they seemed to suffer from this mystery illness, known to them as “the bends,” so named because it made sufferers bend over in pain.
A few years later, in 1843, the Royal Navy established the first scuba diving school.
Later still, in 1864, Benoît Rouquayrol and Auguste Denayrouze designed a demand valve that delivered air upon inhalation; an early version of the “Aqua-Lung” previously mentioned and later invented, and that was originally conceived as a device to be used by miners.
The air came from a tank on the wearer’s back, and was filled from the surface. The diver could untether for only a short time, but it was a significant step towards a self-contained unit.
Meanwhile, Henry Fleuss developed what was arguably the world’s first “rebreather”; something that uses oxygen instead of compressed air, absorbing the carbon dioxide of the user’s breath and allowing the unused oxygen content still within to be recycled and included a rope soaked in potash to act as the carbon dioxide absorbent. With it, dive times of up to 3 hours were possible. Adapted versions of this rebreather were extensively used by the British, Italian and German militaries during the 1930s and through World War II.
It’s easy to see that the pace and evolution of scuba diving was increasing radical, diving equipment was improving, along with the understanding of the dangers, and the beneficial roles that divers could play were broadening. And yet, they were being hampered by the mystifying sickness that plagued divers without explanation. So, in 1908, at the request of the British Government, a Scottish physiologist by the name of John Scott Haldane started research. And, as a result, a stunning 80 years after the first diving helmet was used, the first “diving tables” were produced; a chart to assist in determining a decompression schedule, by the Royal and US Navies, their development undoubtedly sparing countless divers from decompression sickness.
After that, the pace only continued. US Navy divers set a 91 meter (300ft) scuba diving record in 1915; the first self-contained diving system was developed and marketed in 1917; helium and oxygen mixtures were researched in 1920; wooden fins were patented in 1933; and shortly afterward, Rouquayrol and Denayrouzes’ design was reconfigured by French inventor, Yves Le Prieur.
Still in 1917, the Mark V diving helmet was introduced and used for salvage work during World War II. It became standard US Navy diving equipment. When escape artist Harry Houdini invented a diver’s suit in 1921 that allowed divers to easily and safely get out of suits underwater it was called the Houdini suit.
Le Prieur’s improvements featured a high-pressure tank that freed the diver from all hoses, the downside being that, to breathe, the diver opened a tap which significantly reduced possible dive times. It was at this point that the first recreational scuba diving clubs were formed, and diving itself took a step away from its military routes and into leisure. INTO THE LIMELIGHT AND PUBLIC DOMAIN The depths continued to increase, and in 1937, Max Nohl reached a depth of 128 meters (420ft); the same year that the O-ring, a type of seal that would become very important in scuba diving, was invented.
Divers and filmmakers, Hans Hass and Jacques-Yves Cousteau both produced the first documentaries filmed underwater which enticed and lured would-be adventurers into the depths. Their inadvertent marketing of a new sport coupled with Jacques’ invention of the Aqua-Lung in 1942 paved the way for the leisurely pastime enjoyable today.
By 1948, Frédéric Dumas had taken the Aqua-Lung to 94 meters (308ft) and Wilfred Bollard had dived to 165 meters (540ft).
The next few years saw a further series of developments that all contributed to more people diving: The company, Mares, was founded, creating scuba diving equipment. The Aqua-Lung went into production and was made available in the USA. Underwater camera housings and strobes were developed for both still and moving pictures. Skin Diver Magazine made its debut.
The documentary by Jacques-Yves Cousteau, The Silent World, was released. Sea Hunt aired on TV. Another scuba diving company, Cressi, imported dive gear to the US. The first neoprene suit, also known as a wet suit, was designed. The first diving instruction courses were taught. The film Frogmen was released.
And on it went, many more books and films being released to feed the suddenly ravenous imagination of audiences.
20,000 Leagues Under The Sea was one such story; adapted from Jules Vern’s novel first published in 1870, today, the 1954 film is over 60 years old and its influence still strong. Where else could that young, animated, wandering clownfish of today’s silver screen have gotten his name if not from the Nautilus’ commander, Captain Nemo? Although courses had previously been available, it wasn’t until 1953 that the first scuba diving training agency, BSAC , The British Sub-Aqua Club, was created. Along with it, the YMCA, the National Association of Underwater Instructors (NAUI), and the Professional Association of Diving Instructors (PADI), all formed between 1959 and 1967.
This was largely due to the fact that rates of scuba accidents had risen sharply, and a need for proper training became evident. By the 1970s, certification cards for scuba divers were required for air fills. The Professional Association of Diving Instructors (PADI) is a recreational diving membership and diver training organization founded in 1966 by John Cronin and Ralph Erickson. Cronin was originally a NAUI instructor who decided to form his own organization with Erickson, and to break diver training down into several modular courses instead of the single universal course then prevalent
The first stabilization jackets were introduced by Scubapro, known as “stab jackets,” and they were the forerunners of the BCD (buoyancy control device). Diving, at this point, still followed navy diving tables , which were created with decompression diving in mind, and were overly penalizing for the type of repetitive leisure dives most hobbyists were now undertaking.
In 1988, Diving Science and Technology (DSAT) , an affiliate of PADI , created the recreational scuba diving planner, or RDP, specifically for leisure divers. By the 90s, technical diving had entered the scuba diving psyche, half a million new scuba divers were certified annually, and dive computers were on practically every diver’s wrist. The term technical diving has been credited to Michael Menduno, who was editor of the (now defunct) diving magazine aquaCorps Journal.
In the early 1990s, propelled by the publication of aquaCorps, technical scuba diving emerged as a distinct new division of sport diving. With its roots in cave diving, technical diving appealed to the breed of diver that recreational scuba diving had left behind, the adventurer willing to accept more risk.
Technical diving will change more than recreational diving in the immediate future. This is because it’s a younger sport and still maturing, and because technical divers are more technology oriented and less price sensitive than the average mainstream diver. ONWARDS AND UPWARDS. Today, enriched compressed air or nitrox is in common usage to reduce the proportion of nitrogen in breathing gas mixtures, most modern scuba divers have a camera, rebreathers are the staple of technical divers, and Ahmed Gabr holds the first open circuit scuba diving record at 332.35 meters (1090.4ft).
In the 21st century, modern scuba diving is a huge industry. Numerous different scuba training courses are available, and PADI alone certifies around 900,000 divers annually.
Destinations, resorts, and liveaboards can be a little overwhelming, but it’s not at all surprising to see parents scuba diving with their children. And the future may hold exciting advances , a satellite imagery driven sub aquatic navigation gadget? Communication devices becoming as ubiquitous as dive computers? (It would be a shame to lose the silent comedy value of today’s underwater signals, but advancement is advancement.)
On top of that, the furthering of reduced underwater restrictions, depths, and amount of time will only continue to increase.
It’s also possible that there will be a fundamental change in the gear that is used. It’s still true that the standard tank, BCD, and regulator set up is bulky, awkward, and heavy, it hasn’t changed much over the years. One possible example and future solution is a design that exists for a recreational rebreather to be built into scuba diving helmets. Divers are constantly dreaming up ideas of how to improve equipment which is constantly evolving even if the basic principle is still the same.
In a very James Bond fashion, crystals that absorb oxygen from water have been synthesized for patients with lung problems, the application of which is obvious for modern scuba diving.
Whatever may await the evolution of underwater exploration, it’s a sure thing that people will never lose their fascination for deep-sea adventure and the excitement and pleasure that goes with it . The undersea world awaits you . Allan Woods PADI MASTER INSTRUCTOR