Instruct: Given a question, retrieve passages that can help answer the question.
Query: What is the deepest diving expedition recorded?
On 23 January 1960, she reached the ocean floor in the Challenger Deep (the deepest southern part of the Mariana Trench), carrying Jacques Piccard and Don Walsh. This was the first time a vessel, manned or unmanned, had reached the deepest known point of the Earth's oceans. The onboard systems indicated a depth of , although this was revised later to ; fairly recently, more accurate measurements have found Challenger Deep to be between and deep.
Sea urchins are established in most seabed habitats from the intertidal downwards, at an extremely wide range of depths. Some species, such as "Cidaris abyssicola", can live at depths of several thousands metres. Many genera are only found in the abyssal zone, including many cidaroids, most of the genera in the Echinothuriidae family, and the "cactus urchins" "Dermechinus". One of the deepest-living families is the "Pourtalesiidae", strange bottle-shaped irregular sea urchins that live only in the hadal zone and have been collected as deep as 6850 metres beneath the surface in the Sunda Trench. Nevertheless, this makes sea urchin the class of echinoderms living the least deep, compared to brittle stars, starfish and crinoids that remain abundant below and sea cucumbers which have been recorded from .
The Abismo Guy Collet (SP-090) is the deepest cave in South America, and the deepest in the world that is formed in quartzite. Located in a tepui in northern Brazil near the border with Venezuela, this cave was first explored by cavers in 2006 to a depth of 671 meters.
Swells dropped to 1–1.5 m on 28 June 2011, allowing more netting of sardines. Sardines were netted at Amanzimtoti; on the main beach and at Chain Rocks. A 22-year-old American marine biology student (research diver) named Paulo Edward Stanchi was attacked by a large dusky shark while diving at Aliwal Shoal Marine Protected Area. The group of divers had encountered a pocket of sardines when a 3 m long dusky shark bit Mr Stanchi on his left leg and hands. Mr Stanchi managed to free himself from the shark, and was treated on the diving boat before being transported to Rocky Bay, where medics stabilised him. He was then airlifted to Nkosi Albert Luthuli Hospital, where he underwent surgery. Dusky sharks generally live offshore, but come closer to the shore during the sardine run. The annual sardine run allowed more dusky sharks in the Aliwal Shoal MPA than usual, but there was no reason for them to show any more interest in divers than usual. Mr Stanchi had been wearing split fins with black and grey stripes, and this may have looked like a small shoal of fish to the shark. Meanwhile, a woman in her 40s broke her leg in the frenzy at Amanzimtoti when the sardines were netted. The woman is believed to have been trying to get some of the sardines when she "stepped wrong" and fractured her leg. Paramedics stabilized her before transporting her to hospital.
Albert R. Behnke "et al." in 1935 were the first to observe visual field contraction (tunnel vision) on dives between and . During World War II, Donald and Yarbrough "et al." performed over 2,000 experiments on oxygen toxicity to support the initial use of closed circuit oxygen rebreathers. Naval divers in the early years of oxygen rebreather diving developed a mythology about a monster called "Oxygen Pete", who lurked in the bottom of the Admiralty Experimental Diving Unit "wet pot" (a water-filled hyperbaric chamber) to catch unwary divers. They called having an oxygen toxicity attack "getting a Pete".
Chevé Cave ( ; ) is a deep cave located in the Sierra Juárez mountain range in the southern Mexico state of Oaxaca. As of 2003, its deepest point has been measured at deep, making it the second deepest known cavern in the Western Hemisphere and the world’s 12th deepest cave. The cave's deepest known point is nearly one vertical mile and seven horizontal miles from the entrance, ending in a terminal sump. The present limit of exploration in Chevé, at 9.3 kilometers from the nearest entrance, represents one of the most remote locations ever attained inside any cave on Earth. The logistics of reaching this point are enormous: more than two kilometers of rope need to be rigged and three underground camps established. Chevé is the deepest proven freshwater hydrological system in the world. Temperatures in Chevé are moderate, ranging from . It has been most thoroughly explored under the leadership of caver Bill Stone.
The Blue Hole is a diving location on the southeast Sinai, a few kilometres north of Dahab, Egypt on the coast of the Red Sea.
The "Lukina jama" cave is 1431 m deep (2013), the deepest cave in Croatia, 14th deepest cave in the world and the deepest cave in southeast Europe. At its foot, there are ponds and streams including one of the largest known colonies of subterranean leeches ("Erpobdella mestrovi"), which has been ascertained to represent a new species, genus and also family. Other species discovered in the system, include the air-breathing land snails "Zospeum tholussum". Like Lukina jama, Slovacka jama, Velebita and Meduza are also located at the "Hajdučki i Rožanski kukovi" special reserve, a dedicated part of the Sjeverni Velebit national park.
Johnson was part of the first South African team to successfully attach a satellite transmitters to a great white shark on 24 July 2001.Johnson has tagged Great White Sharks for research purposes. His major scientific discoveries have been the satellite tracking of Nicole (a 3.6m great white shark) on a return migration from South Africa to Australia and back, and documenting the Great White Shark hunting Cape fur seal at night time, a previously unknown behavior. Between 2001 and 2005 Johnson conducted research on the controversial practice of chumming great white shark for tourism, often called cage diving, where he discovered evidence of conditioning, however he did not link this to increased numbers of attacks on human beings. In January 2008 he led a pilot study to Ponto Do Ora (Mozambique) on the Zambezi shark, also known as the Bull shark.
The lake is deep at its deepest point, which makes it the deepest lake in the United States, the second-deepest in North America and the ninth-deepest in the world. Crater Lake is often referred to as the seventh-deepest lake in the world, but this former listing excludes the approximately depth of subglacial Lake Vostok in Antarctica, which resides under nearly of ice, and the recent report of a maximum depth for Lake O'Higgins/San Martin, located on the border of Chile and Argentina. However, when comparing its average depth of to the average depth of other deep lakes, Crater Lake becomes the deepest in the Western Hemisphere and the third-deepest in the world. The impressive average depth of this volcanic lake is due to the nearly symmetrical caldera formed 7,700 years ago during the violent climactic eruptions and subsequent collapse of Mount Mazama and the relatively moist climate that is typical of the crest of the Cascade Range.
The largest recorded specimen was captured in 2007 by a New Zealand fishing boat off Antarctica. It was initially estimated to measure in length and weigh . The squid was taken back to New Zealand for scientific study. A study on the specimen later showed its actual weight was , but it only measured in total length as a result of the tentacles' shrinking "post mortem".
The cave consists of Chert (known as the Lost River Chert), which is overlaid by the Ste. Genevieve Limestone and St. Louis Limestone, both of which were laid down in the middle to late Mississippian Period. The river appears above ground in three short sections before flowing into the mouth of the cave. The most interesting section is the blue hole, which is the cause of the Lost River being listed by Ripley's Believe it or Not as the "Shortest, deepest river in the world." Plumb bobs indicated that the blue hole was 437 feet deep, while the river itself is only 400 feet long. In fact, the blue hole is only 16 feet deep, but is linked to a further underground river. This caused plumb bobs to be swept underground, returning erroneous measurements.
When "Titanic" sank in 1912 and "Britannic" sank in 1916, their sinkings did not receive the same attention, due to the death toll (1,517 on "Titanic" and 30 on "Britannic"). Because the exact position of the sinking of the "Britannic" is known and the location is shallow, the wreck was discovered relatively easily in 1975. "Titanic", however, drew everyone's attention in 1912. After several attempts, the wreck was finally located by Jean-Louis Michel of Ifremer and Robert Ballard following a top secret mission for the US Navy to investigate the wreckage of two nuclear submarines, USS Thresher (SSN-593) and the USS Scorpion (SSN-589), that sank in the North Atlantic in the 1960s. The discovery of the wreck occurred on 1 September 1985, at 25 kilometres from the position given of the sinking. The wreck lies about 4,000 metres deep, broken in two. The bow is relatively well preserved, but the stern partially imploded, and to a large extent disintegrated during the descent and impact on the seabed.
"Seeteufel (Sea Devil)" was a hand-powered submarine designed by Wilhelm Bauer in 1856. It was made of iron, and was long, wide and deep. It could hold 15 people. After his last submarine, "Brandtaucher" had sunk, Bauer included a diver's chamber in the design. Through this chamber, which worked like an airlock, divers could leave and enter the submerged vessel. He had tried to obtain support for his invention in several countries, like the Austria-Hungary, the British Empire or France. Finally, in 1855, Bauer made a contract with Russia. He built his submarine at the Leutemberg Works, and it was completed on 1 November. In May 1856 it was taken to Kronstadt and testing began. The submarine made 133 successful diving runs, including a dive on 6 September 1856, when musicians played the national anthem of Russia during the coronation of Alexander II. But during the 134th dive, the submarine got stuck in the sand of the seafloor and was later retrieved by a salvage crew.
Jujar is deepest cave of Asia. in 7 September 2015 Jujar cave in eastern front of the Paraw recognized as deepest cave of Iran. an Iranian caving team consist of 24 athlete has discovered 806 meter and 8 centimeter of this cave. before this event Paraw cave (also located in this mount ) was deepest cave of Iran. in August 2016 an international expedition started to discover whole of the cave. eventually they announced that they successfully achieved to more than 1000 meter depth of the cave. thus Jujar became deepest cave of Asia and Iran.
In May 2007, the Caudwell Xtreme Everest undertook a medical study of oxygen levels in human blood at extreme altitude. Over 200 volunteers climbed to Everest Base Camp where various medical tests were performed to examine blood oxygen levels. A small team also performed tests on the way to the summit. Even at base camp, the low partial pressure of oxygen had direct effect on blood oxygen saturation levels. At sea level, blood oxygen saturation is generally 98–99%. At base camp, blood saturation fell to between 85 and 87%. Blood samples taken at the summit indicated very low oxygen levels in the blood. A side effect of low blood oxygen is a greatly increased breathing rate, often 80–90 breaths per minute as opposed to a more typical 20–30. Exhaustion can occur merely attempting to breathe.
The Colca Canyon, twice as deep as the Grand Canyon in the United States, is situated in the province of Caylloma. The Cotahuasi Canyon is in the La Union Province. Colca Valley provides incredible close-up views of majestic Andean condors soaring in their natural habitat. Cotahuasi, at , is thought to be the deepest canyon in the world. Both canyons offer spectacular scenery and villages as yet unaffected by the modern world.
An autonomous starfish-killing robot called COTSBot has been developed and as of September 2015 was close to being ready for trials on the Great Barrier Reef. The COTSbot, which has a neural net-aided vision system, is designed to seek out crown-of-thorns starfish and give them a lethal injection of bile salts. After it eradicates the bulk of the starfish in a given area, human divers can move in and remove the survivors. Field trials of the robot have begun in Moreton Bay in Brisbane to refine its navigation system, according to Queensland University of Technology researcher Matthew Dunbabin. There are no crown-of-thorns starfish in Moreton Bay, but when the navigation has been refined, the robot will be used on the reef.
The lowest audible SPL for a human diver with normal hearing is about 67 dB re 1 μPa, with greatest sensitivity occurring at frequencies around 1 kHz. This corresponds to a sound intensity 5.4 dB, or 3.5 times, higher than the threshold in air (see Measurements above).
The heaviest known cephalopod, and the largest living invertebrate, is the colossal squid. The largest recorded specimen of this species, caught in the Ross Sea in 2007, weighed . However, its beak is not the largest known from this species; even bigger colossal squid beaks have been recovered from the stomachs of sperm whales, indicating that this species can grow larger still.
In 1993, a photographer attempting to take pictures of a lava ocean entry died, and several tourists were injured, when a lava bench collapsed. In 2000, two people were found dead near a lava ocean entry from Kīlauea, likely killed by laze. Sulfur Dioxide emissions can also be fatal, especially to people suffering from respiratory ailments. In 2018 lava spatter from Kīlauea broke a man's leg, and another 23 people on a tour boat were injured by a steam explosion at a lava ocean entry from the same eruption.
In the following years, Denlay and Tysall mounted several larger expeditions to survey "Atlanta", exploring and videoing the wreck in detail to a depth of at the bow. The civil unrest in Solomon Islands from late 1998 prevented further diving around Guadalcanal for several years. However, on the final expedition that year, the then deepest wreck dive by a woman was made by Kevin's wife, Mirja, on "Atlanta". Denlay's last visit to the wreck was in 2002 using a closed circuit rebreather or CCR, the first CCR dive on "Atlanta". Since then, very few dives have been conducted on "Atlanta", although in May 2011 a very experienced deep diving team from "Global Underwater Explorers" successfully videoed the wreck for documentary purposes, the first survey of the wreck since Denlay's expeditions up to 1998.
During the course of his expeditions Beebe gradually developed an interest in marine biology, ultimately leading to his 1930s dives in the Bathysphere, along with its inventor, Otis Barton, off the coast of Bermuda. This was the first time a biologist observed deep-sea animals in their native environment, and set several successive records for the deepest dive ever performed by a human, the deepest of which stood until it was broken by Barton 15 years later. Following his Bathysphere dives, Beebe returned to the tropics and began to focus his study on the behavior of insects. In 1949, he founded a tropical research station in Trinidad which he named Simla, and which remains in operation as part of the Asa Wright Nature Centre. Beebe's research at Simla continued until his death from pneumonia in 1962 at the age of 84.
On 24 November 2004, Verna van Schaik set the Guinness Woman's World Record for the deepest dive with a dive to .In Mo Hayder's novel "Ritual" (2008), the death of the parents of one of the protagonists while diving in Bushman's Hole is an important plot device.
The Bathysphere (Greek: "βαθύς", "bathus", "deep" and "σφαῖρα", "sphaira", "sphere") was a unique spherical deep-sea submersible which was unpowered and lowered into the ocean on a cable, and was used to conduct a series of dives off the coast of Bermuda from 1930 to 1934. The Bathysphere was designed in 1928 and 1929 by the American engineer Otis Barton, to be used by the naturalist William Beebe for studying undersea wildlife. Beebe and Barton conducted dives in the Bathysphere together, marking the first time that a marine biologist observed deep-sea animals in their native environment. Their dives set several consecutive world records for the deepest dive ever performed by a human. The record set by the deepest of these, to a depth of meters on August 15, 1934, lasted until it was broken by Barton in 1949.