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115-755: In January 1973, lava flow from nearby Eldfell destroyed half the town and threatened to close its harbour, its main income source. An operation to cool the advancing lava with sea water saved the harbour. In tradition, Herjólfur Bárðarson was said to be the first person to settle in Heimaey. According to the Landnáma , he built his farm in Herjólfsdalur (literally: Herjólf's valley) about 900. The archaeological excavation in 1971 of ancient ruins in Herjólfsdalur revealed that there had been settlement nearly 100 years earlier. In 1627, three Arab pirate ships from

230-418: A "massive, blocky ʻaʻā lava flow which moved slowly but relentlessly toward the north, northeast, and east." Volcanic gases were collected from several locations. Gases collected at sea along the submerged part of active eruptive fissure were dominantly carbon dioxide and gases from cooling submerged lava flows were about 70 percent hydrogen. (Richard & James, 1983) Poisonous gas was found at low areas on

345-487: A 2:3 ratio during the 1947 expedition. A few years later, another adventurer, William Willis , claimed to have drunk two cups of seawater and one cup of fresh per day for 70 days without ill effect when he lost part of his water supply. During the 18th century, Richard Russell advocated the medical use of this practice in the UK, and René Quinton expanded the advocation of this practice to other countries, notably France, in

460-467: A balance of minerals within their diet, but it also impacts the amount of iron that is regenerated back into the ocean. The whale's excretions also contain the absorbed iron which would allow iron to be reinserted into the ocean’s ecosystem. Overall, one mineral deficiency such as iron in the Southern Ocean can spark a significant chain of disturbances within the marine ecosystems which demonstrates

575-589: A capacity of up to 1000 litres per second (265 US gallons per second), were brought in from the United States . After these pumps began to cool the flow advancing towards the town, its movement slowed dramatically and soon stopped. Failure of pump shafts became a problem after a few weeks, probably because they were designed for pumping oil rather than water, and new and improved shafts had to be manufactured in Reykjavík and brought in. One notable feature of

690-478: A chemical/ tectonic system which removes as much salt as is deposited; for instance, sodium and chloride sinks include evaporite deposits, pore-water burial, and reactions with seafloor basalts . Climate change , rising levels of carbon dioxide in Earth's atmosphere , excess nutrients, and pollution in many forms are altering global oceanic geochemistry . Rates of change for some aspects greatly exceed those in

805-580: A day, mixed with fresh water in a 2:3 ratio, produces no ill effect. The French physician Alain Bombard survived an ocean crossing in a small Zodiak rubber boat using mainly raw fish meat, which contains about 40% water (like most living tissues), as well as small amounts of seawater and other provisions harvested from the ocean. His findings were challenged, but an alternative explanation could not be given. In his 1948 book The Kon-Tiki Expedition , Thor Heyerdahl reported drinking seawater mixed with fresh in

920-414: A diminutive island that was soon overtaken by the advancing delta. The first lavas erupted by Eldfell had a mugearitic chemical composition but within a few weeks the volcano was erupting less fractionated lavas which had a hawaiitic composition. By early May, the lava flow was between 9.1 and 21.0 m (10 and 23 yd) in height. It averaged more than 37 m (40 yd) and in some places

1035-458: A few people who were unable to travel by boat were evacuated by air—primarily the elderly and patients from the hospital. Planes were sent from Reykjavík and Keflavik to help speed the process. Within six hours of the onset of the eruption, almost all of the 5,300 people of the island were safely on the mainland. A few people remained to carry out essential functions and to salvage belongings from threatened houses. Cattle, horses and sheep on

1150-523: A few puffins to share at the festival, or to eat at home. Eldfell Eldfell is a volcanic cone just over 200 metres (660 ft) high on the Icelandic island of Heimaey . It formed in a volcanic eruption which began without warning on the eastern side of Heimaey , in the Westman Islands , on 23 January 1973. The name means Hill of Fire in Icelandic . The eruption caused

1265-474: A hunt for undiscovered chemicals in organisms that have evolved in deep sea trenches, hoping to find "the next generation" of antibiotics, anticipating an "antibiotic apocalypse" with a dearth of new infection-fighting drugs. The EU-funded research will start in the Atacama Trench and then move on to search trenches off New Zealand and Antarctica. The ocean has a long history of human waste disposal on

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1380-594: A litre of seawater may hold more than 20,000 species. Mitchell Sogin from the Marine Biological Laboratory feels that "the number of different kinds of bacteria in the oceans could eclipse five to 10 million." Bacteria are found at all depths in the water column , as well as in the sediments, some being aerobic, others anaerobic. Most are free-swimming, but some exist as symbionts within other organisms – examples of these being bioluminescent bacteria. Cyanobacteria played an important role in

1495-411: A major crisis for the island and led to its temporary evacuation . Volcanic ash fell over most of the island, destroying around 400 homes, and a lava flow threatened to close off the harbour, the island's main income source via its fishing fleet. An operation was mounted to cool the advancing lava flow by pumping sea water onto it, which was successful in preventing the loss of the harbour. After

1610-436: A man who had broken into a chemist's store to acquire drugs was suffocated by toxic fumes. Carbon dioxide, with small amounts of poisonous gases, became concentrated in many buildings partially buried by tephra, and several other people were affected when entering these buildings. Efforts to mitigate the hazards presented by the accumulation of poisonous gas included the building of a large tephra wall to divert gases away from

1725-443: A marked effect on microbial life in the vicinity, as well as harbouring pathogens and toxins affecting all forms of marine life . The protist dinoflagellates may at certain times undergo population explosions called blooms or red tides , often after human-caused pollution. The process may produce metabolites known as biotoxins, which move along the ocean food chain, tainting higher-order animal consumers. Pandoravirus salinus ,

1840-413: A more sustainable water supply from seawater. Although desalination also comes with environmental concerns, such as costs and resources, researchers are working closely to determine more sustainable practices, such as creating more productive water plants that can deal with larger water supplies in areas where these plans weren't always available. Although seawater extractions can benefit society greatly, it

1955-511: A salinity of 35 g/kg. The thermal conductivity decreases with increasing salinity and increases with increasing temperature. The water in the sea was thought to come from the Earth's volcanoes , starting 4 billion years ago, released by degassing from molten rock. More recent work suggests much of the Earth's water may come from comets . Scientific theories behind the origins of sea salt started with Sir Edmond Halley in 1715, who proposed that salt and other minerals were carried into

2070-538: A series of small tremors began to occur around Heimaey. They were too weak to be felt by the residents of the island, but a seismic station 60 kilometres (37 mi) away, near the mainland, recorded over 100 large tremors between 01:00 and 03:00 on 22 January that appeared to be emanating from south of Heimaey. The tremors continued at a reduced rate until 11:00 that day, after which they stopped until 23:00 that evening. From 23:00 until 01:34 on 23 January, seven tremors were detected that grew shallower and more intense, while

2185-489: A species of very large virus, with a genome much larger than that of any other virus species, was discovered in 2013. Like the other very large viruses Mimivirus and Megavirus , Pandoravirus infects amoebas, but its genome, containing 1.9 to 2.5 megabases of DNA, is twice as large as that of Megavirus , and it differs greatly from the other large viruses in appearance and in genome structure. In 2013 researchers from Aberdeen University announced that they were starting

2300-633: A total of US$ 1,447,742 at the time. The eruption made headlines around the world when it began, and was covered constantly by Icelandic news crews throughout. In Europe, the eruption was one of the biggest news items while it continued, competing for front-page space with breakthroughs then being made in the Vietnam War peace talks in Paris . The efforts of the islanders to halt the lava flows received particular attention, with coverage in publications such as National Geographic . The attention focused on

2415-557: Is about 1000 mOsm/L. Small amounts of other substances are found, including amino acids at concentrations of up to 2 micrograms of nitrogen atoms per liter, which are thought to have played a key role in the origin of life . Research in 1957 by the Scripps Institution of Oceanography sampled water in both pelagic and neritic locations in the Pacific Ocean. Direct microscopic counts and cultures were used,

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2530-507: Is above the kidney's maximum concentrating ability. Eventually the blood's sodium concentration rises to toxic levels, removing water from cells and interfering with nerve conduction, ultimately producing fatal seizure and cardiac arrhythmia . Survival manuals consistently advise against drinking seawater. A summary of 163 life raft voyages estimated the risk of death at 39% for those who drank seawater, compared to 3% for those who did not. The effect of seawater intake on rats confirmed

2645-448: Is an indicator that krill is in whale diets. Antarctic krill had an average iron level of 174.3mg/kg dry weight, but the iron in the krill varied from 12 to 174 mg/kg dry weight. The average iron concentration of the muscular tissue of blue whales and fin whales was 173 mg/kg dry weight, which demonstrates that the large marine mammals are important to marine ecosystems such as they are to the Southern Ocean. In fact, to have more whales in

2760-509: Is complicated by the chemical properties of seawater, and several distinct pH scales exist in chemical oceanography . There is no universally accepted reference pH-scale for seawater and the difference between measurements based on different reference scales may be up to 0.14 units. Seawater contains more dissolved ions than all types of freshwater. However, the ratios of solutes differ dramatically. For instance, although seawater contains about 2.8 times more bicarbonate than river water,

2875-476: Is considered a superior taste. A restaurant run by Joaquín Baeza sources as much as 60,000 litres a month from supplier Mediterranea Animals such as fish, whales, sea turtles , and seabirds , such as penguins and albatrosses , have adapted to living in a high-saline habitat. For example, sea turtles and saltwater crocodiles remove excess salt from their bodies through their tear ducts . Minerals have been extracted from seawater since ancient times. Currently

2990-557: Is crucial to consider the environmental impact and to ensure that all extractions are conducted in a way that acknowledges and considers the associated risks to the sustainability of seawater ecosystems. ASTM International has an international standard for artificial seawater : ASTM D1141-98 (Original Standard ASTM D1141-52). It is used in many research testing labs as a reproducible solution for seawater such as tests on corrosion, oil contamination, and detergency evaluation. The minerals found in seawater can also play an important role in

3105-421: Is not easily accessible. Although it is not typical to use salt water as a means to grow plants as the salt gathers and ruins the surrounding soil, it has been proven to be successful in sand and gravel soils. Large-scale desalination of seawater is another factor that would contribute to the success of agriculture farming in dry, desert environments. One of the most successful plants in salt water agriculture

3220-523: Is the Red Sea , where high rates of evaporation , low precipitation and low river run-off, and confined circulation result in unusually salty water. The salinity in isolated bodies of water can be considerably greater still – about ten times higher in the case of the Dead Sea . Historically, several salinity scales were used to approximate the absolute salinity of seawater. A popular scale

3335-399: Is the halophyte . The halophyte is a salt tolerant plant whose cells are resistant to the typically detrimental effects of salt in soil. The endodermis forces a higher level of salt filtration throughout the plant as it allows for the circulation of more water through the cells. The cultivation of halophytes irrigated with salt water were used to grow animal feed for livestock ; however,

3450-593: Is typically limited to a range between 7.5 and 8.4. However, there is no universally accepted reference pH-scale for seawater and the difference between measurements based on different reference scales may be up to 0.14 units. Although the vast majority of seawater has a salinity of between 31 and 38 g/kg, that is 3.1–3.8%, seawater is not uniformly saline throughout the world. Where mixing occurs with freshwater runoff from river mouths, near melting glaciers or vast amounts of precipitation (e.g. monsoon ), seawater can be substantially less saline. The most saline open sea

3565-453: The Age of Sail . Larger sailing warships with large crews, such as Nelson 's HMS  Victory , were fitted with distilling apparatus in their galleys . The natural sea salt obtained by evaporating seawater can also be collected and sold as table salt , typically sold separately owing to its unique mineral make-up compared to rock salt or other sources. A number of regional cuisines across

Heimaey - Misplaced Pages Continue

3680-550: The Benguela Current upwelling zone, eventually falling to the seafloor. Bacteria-like Archaea surprised marine microbiologists by their survival and thriving in extreme environments, such as the hydrothermal vents on the ocean floor. Alkalotolerant marine bacteria such as Pseudomonas and Vibrio spp. survive in a pH range of 7.3 to 10.6, while some species will grow only at pH 10 to 10.6. Archaea also exist in pelagic waters and may constitute as much as half

3795-563: The Holocene epoch. Heimaey , the largest island in the group and the only inhabited one, also contains some material from the Pleistocene era. The most prominent feature on Heimaey before 1973 was Helgafell , a 200 meters (650 ft) high volcanic cone formed in an eruption about 5,000 years ago. The Vestmannaeyjar archipelago was settled in about 874 AD, originally by escaped Insular slaves belonging to Norse settlers on

3910-558: The North American and Eurasian Plates are moving apart, and also over the Iceland hotspot , which greatly enhances the volcanic activity. It is estimated that a third of all the basaltic lava erupted in the world in recorded history has been produced by Icelandic eruptions. The Vestmannaeyjar (Westman Islands) archipelago lies off the south coast of Iceland, and consists of several small islands, all formed by eruptions in

4025-530: The Ottoman -controlled Barbary Coast raided several towns on the south coast of Iceland and outlying islands. They attacked Grindavík and Heimaey. In Grindavík, townspeople could flee into the lava field of Reykjanes and hide indefinitely. Heimaey was so isolated that it was vulnerable and people suffered. Many heroic stories were told of the people who survived the invasion, most notably Guðríður Símonardóttir . Better known as Tyrkja-Gudda (Turkish-Gudda), she

4140-454: The oil and gas released from the operation of merchant ships decreases the air quality and causes more pollution both in the seawater and surrounding areas. Another human use of seawater that has been considered is the use of seawater for agricultural purposes. In areas with higher regions of sand dunes , such as Israel , the use of seawater for irrigation of plants would eliminate substantial costs associated with fresh water when it

4255-552: The percentage of bicarbonate in seawater as a ratio of all dissolved ions is far lower than in river water. Bicarbonate ions constitute 48% of river water solutes but only 0.14% for seawater. Differences like these are due to the varying residence times of seawater solutes; sodium and chloride have very long residence times, while calcium (vital for carbonate formation) tends to precipitate much more quickly. The most abundant dissolved ions in seawater are sodium, chloride, magnesium , sulfate and calcium. Its osmolarity

4370-484: The 1960s, but only a few grams of uranium were extracted in Japan in the late 1990s. The main issue is not one of technological feasibility but that current prices on the uranium market for uranium from other sources are about three to five times lower than the lowest price achieved by seawater extraction. Similar issues hamper the use of reprocessed uranium and are often brought forth against nuclear reprocessing and

4485-687: The 20th century. Currently, it is widely practiced in Nicaragua and other countries, supposedly taking advantage of the latest medical discoveries. Like any other type of raw or contaminated water , seawater can be evaporated or filtered to eliminate salt, germs, and other contaminants that would otherwise prevent it from being considered potable . Most oceangoing vessels desalinate potable water from seawater using processes such as vacuum distillation or multi-stage flash distillation in an evaporator , or, more recently, reverse osmosis . These energy-intensive processes were not usually available during

4600-512: The Westman Islands were back to normal production levels. Counter-intuitively, the new lava field actually improved the harbour in Westman Islands. Also counter-intuitive, the forced displacement had a large positive causal effect on both the earnings and education for those who were younger than 25 years old at the time of the eruption. The insides of lava flows can remain at temperatures of several hundred degrees for many years due to

4715-465: The advancing flow, and a network of pipes was laid on top of the lava to distribute the seawater over as wide an area as possible. Wooden supports for the pipes caught fire where the lava was hottest, and even aluminium supports melted, but the pipes themselves were prevented from melting by the cold seawater flowing through them. Up to 12,000 square metres (3 acres ) of lava flow could be cooled at one time, with internal barriers then being created within

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4830-408: The air from the fissures. Volcanic ash was blown to sea. Later, the situation deteriorated. When the fissures closed, the eruption converted to a concentrated lava flow that headed toward the harbour. The winds changed, and half a million cubic metres of ash blew on the town. During the night, the 5,000 inhabitants of the island were evacuated, mostly by fishing boats, as almost the entire fishing fleet

4945-432: The amount of iron that can be recycled and stored in seawater. A positive feedback loop is created, increasing the overall productivity of marine life in the Southern Ocean. Organisms of all sizes play a significant role in the balance of marine ecosystems with both the largest and smallest inhabitants contributing equally to recycling nutrients in seawater. Prioritizing the recovery of whale populations because they boost

5060-415: The animals that were fed these plants consumed more water than those that did not. Although agriculture from use of saltwater is still not recognized and used on a large scale, initial research has shown that there could be an opportunity to provide more crops in regions where agricultural farming is not usually feasible. Accidentally consuming small quantities of clean seawater is not harmful, especially if

5175-537: The assumption that its vast size makes it capable of absorbing and diluting all noxious material. While this may be true on a small scale, the large amounts of sewage routinely dumped has damaged many coastal ecosystems, and rendered them life-threatening. Pathogenic viruses and bacteria occur in such waters, such as Escherichia coli , Vibrio cholerae the cause of cholera , hepatitis A , hepatitis E and polio , along with protozoans causing giardiasis and cryptosporidiosis . These pathogens are routinely present in

5290-404: The ballast water of large vessels, and are widely spread when the ballast is discharged. The speed of sound in seawater is about 1,500 m/s (whereas the speed of sound is usually around 330 m/s in air at roughly 101.3 kPa pressure, 1 atmosphere), and varies with water temperature, salinity, and pressure. The thermal conductivity of seawater is 0.6 W/mK at 25 °C and

5405-477: The centre of the town of Heimaey, approximately 200 metres (650 ft) east of Kirkjubær ( Church farm ), where the island's church had once been located. The fissure rapidly extended from 300 metres to a length of 2 kilometres (1.2 mi), crossing the island from one shore to the other. Submarine activity also occurred just offshore at the northern and southern ends of the fissure. Spectacular lava fountaining 50 to 150 metres high occurred along

5520-424: The condition of the sea post-extraction, and constant monitoring. The use of technology, such as underwater drones , can facilitate sustainable extractions. The use of low-carbon infrastructure would also allow for more sustainable extraction processes while reducing the carbon footprint from mineral extractions. Another practice that is being considered closely is the process of desalination in order to achieve

5635-404: The contrary) is that the gut cannot absorb water at such concentrations, so that there is no benefit in drinking such water. The salinity of Baltic surface water, however, is never 2%. It is 0.9% or less, and thus never higher than that of bodily fluids. Drinking seawater temporarily increases blood's NaCl concentration. This signals the kidney to excrete sodium, but seawater's sodium concentration

5750-422: The cooling, the lava tongue [into the harbor] could be expected to…extend further along its direction of movement…for a whole month longer than it actually did. It failed by only about 100 meters to block the entrance to the harbor". The cooling operation ended on 10 July 1973, and approximately 7.3 million cubic metres of seawater were pumped. This eruption was a special case where the method used to control

5865-433: The density of seawater is 1023.6 kg/m . Deep in the ocean, under high pressure, seawater can reach a density of 1050 kg/m or higher. The density of seawater also changes with salinity. Brines generated by seawater desalination plants can have salinities up to 120 g/kg. The density of typical seawater brine of 120 g/kg salinity at 25 °C and atmospheric pressure is 1088 kg/m . The pH value at

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5980-495: The direct counts in some cases showing up to 10 000 times that obtained from cultures. These differences were attributed to the occurrence of bacteria in aggregates, selective effects of the culture media, and the presence of inactive cells. A marked reduction in bacterial culture numbers was noted below the thermocline , but not by direct microscopic observation. Large numbers of spirilli -like forms were seen by microscope but not under cultivation. The disparity in numbers obtained by

6095-419: The dissolved salts increase the mass by a larger proportion than the volume. The freezing point of seawater decreases as salt concentration increases. At typical salinity, it freezes at about −2 °C (28 °F). The coldest seawater still in the liquid state ever recorded was found in 2010, in a stream under an Antarctic glacier : the measured temperature was −2.6 °C (27.3 °F). Seawater pH

6210-569: The eastern part of Vestmannaeyjar. A wall was constructed between the vent and town to divert the gas, and a long trench was excavated for the steam to escape. However, none of these measures were completely effective. (Richard & James, 1983) In the early hours of the eruption, the Icelandic State Civil Defence Organisation evacuated the entire population of Heimaey, having previously developed evacuation plans for an emergency such as this. The evacuation

6325-468: The epicenter moved closer to the town of Vestmannaeyjar. The largest tremor measured 2.7 on the Richter scale . Small tremors are very common at plate boundaries, and nothing here indicated that they heralded a major eruption. The onset of the eruption was therefore almost entirely unexpected. At about 01:55 on 23 January, a fissure opened up on the eastern side of the island, barely a kilometre away from

6440-491: The eruption, the islanders used heat from the cooling lava flows to provide hot water and to generate electricity . They also used some of the extensive tephra , fall-out of airborne volcanic material, to extend the runway at the island's small airport and as landfill on which 200 new houses were built. Iceland is a region of frequent volcanic activity, due to its location astride the Mid-Atlantic Ridge , where

6555-439: The eruption. The eruption is described by John McPhee in his book The Control of Nature . Heimaey is home to around 4,500 people, and eight million puffins every summer. Many millions of other birds migrate there for breeding and feeding. The island is connected to the rest of Iceland by a ferry and Vestmannaeyjar Airport . Most people on the island live off fishing. During an annual festival, people are allowed to catch

6670-505: The evolution of ocean processes, enabling the development of stromatolites and oxygen in the atmosphere. Some bacteria interact with diatoms , and form a critical link in the cycling of silicon in the ocean. One anaerobic species, Thiomargarita namibiensis , plays an important part in the breakdown of hydrogen sulfide eruptions from diatomaceous sediments off the Namibian coast, and generated by high rates of phytoplankton growth in

6785-425: The flow of the lava was blocky, covered with volcanic bombs and was a reddish oxidised colour. After cooling, the surface became more jagged and was much more difficult to walk on, and the flow surface turned from black to grey. (Richard & James, 1983) Water cooling of the lava was slow but efficient, with almost all the water converted to steam . Once the viability of lava cooling had been proven, efforts to halt

6900-402: The flow, which thickened and piled up upon itself. The work involved in laying pipes over an active lava flow was highly dangerous, with low visibility due to the extensive emission of steam. Rough tracks were made onto the flow by bulldozing tephra, but these tracks quickly became very uneven and moved several metres a day. The pipelayers used bulldozers and walkie-talkies to advance through

7015-494: The flows were increased. The pumping capacity was increased in early March, when a large chunk of the crater wall broke away from the summit of Eldfell and began to be carried along the top of the lava flow towards the harbour. The chunk, dubbed Flakkarinn ( The Wanderer ), would have seriously threatened the viability of the harbour if it had reached it, and the dredging boat Sandey was brought in on 1 March to prevent its advance. Professor Þorbjörn Sigurgeirsson provided advice to

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7130-501: The flows. Each plant extracted energy from a square 100 metres (330 ft) on each side, by percolating water down into the hot parts and collecting the resulting steam. Up to 40 megawatts (MW) of power could be generated by the plants, which also then supplied hot water to nearly every house on the island. The tephra produced by the eruption was used to extend the runways at the island's small airport, and also as landfill on which 200 new homes were built. By mid-1974, about half

7245-530: The four most concentrated metals – Na , Mg , Ca and K – are commercially extracted from seawater. During 2015 in the US 63% of magnesium production came from seawater and brines. Bromine is also produced from seawater in China and Japan. Lithium extraction from seawater was tried in the 1970s, but the tests were soon abandoned. The idea of extracting uranium from seawater has been considered at least from

7360-413: The ground to average depths of about 40 metre (130 ft), reaching 100 metre (330 ft) thick in places. Later on in the eruption, a surge of lava destroyed one fish processing plant and damaged two others, and also demolished the town's power generating plant. Despite the eruption's close proximity to the town and the extensive property damage, only one fatality could be attributed to the eruption -

7475-455: The harbour improved by the new lava breakwater, the fishing industry regained its former vigour and the island today remains the most important fishing centre in the nation, as over a third of Iceland's total fish catch is from this harbour. By the end of the eruption, Eldfell stood about 220 metres (720 ft) above sea level. Since then, its height has dropped by 18 to 20 metres (60 to 65 feet), due to slumping and compacting of

7590-455: The harbour. Flakkarinn rafted several hundred metres towards the harbour along the top of the lava flow, but came to a halt well away from the water's edge. By the end of 1975, the population of the Westman Islands had returned to roughly 85% of its pre-eruption level. 42% among those with destroyed houses did not return before the end of 1975, while the rate was only 27% among those whose houses were not destroyed. By 1974, fishing companies in

7705-640: The heavy tephra fall had abated, but lava flows began to cause serious damage. Submarine activity just north of the fissure severed an electric power cable and a water pipeline which supplied electrical power and water from the Icelandic mainland, and lava began to flow towards the harbour , a situation which caused serious concerns - if the harbour was blocked, the island's fishing industry would be devastated. By early May, about 300 buildings had been engulfed by lava flows or gutted by fire and 60-70 homes had been buried by tephra.(Richard & James, 1983) As Heimaey

7820-528: The historical and recent geological record. Major trends include an increasing acidity , reduced subsurface oxygen in both near-shore and pelagic waters, rising coastal nitrogen levels, and widespread increases in mercury and persistent organic pollutants. Most of these perturbations are tied either directly or indirectly to human fossil fuel combustion, fertilizer, and industrial activity. Concentrations are projected to grow in coming decades, with negative impacts on ocean biota and other marine resources. One of

7935-458: The important role that seawater plays in the food chain . Upon further analysis of the dynamic relationship between diatoms, krill, and baleen whales, fecal samples of baleen whales were examined in Antarctic seawater. The findings included that iron concentrations were 10 million times higher than those found in Antarctic seawater, and krill was found consistently throughout their feces which

8050-413: The island as a result of the eruption led to a later upsurge in tourism once the eruption was over. The volume of lava being emitted during the eruption fell steadily after the first few days. From its initial rate of 100 cubic metres per second (3,500 cu ft/s), the emission rate fell to about 60 m /s (2,100 cu ft/s) by 8 February, and just 10 m /s (350 cu ft/s) by

8165-407: The island were slaughtered. On the mainland, friends, relatives and strangers offered shelter and housing. By the end of the day, all 5,300 people were spread around cities and towns on the mainland. Houses close to the rift were soon destroyed by lava flows and tephra fall. A few days after the eruption began, the prevailing wind direction moved to the west, resulting in extensive tephra falls over

8280-453: The lava cooling operation was the deposit of large amounts of salt where seawater was sprayed onto the lava. Large expanses of flow became encrusted with extensive white deposits, and it was estimated that up to 220,000 tonnes (240,000 short tons ) of salt was deposited in total. Sigurgeirsson called these protective measures "undoubtedly the most extensive that have ever been used in a volcanic eruption" and said that "had it not been for

8395-413: The lava could be impeded by prematurely solidifying the advancing lava-flow front. The first attempt to slow the lava flow by spraying the leading edge with sea water began on 6 February, and although the volume of water being pumped on was rather small at 100 litres per second (26 US (liquid) gallons per second), the flow was noticeably affected. The lava changed as water poured on it. Before cooling,

8510-442: The lava was suited to local conditions. Firstly, the initial eruption was only 1,000 m (1,100 yd) from the centre of town and harbour. Next, the flow of lava was slow and allowing time to plan and carry out control. Thirdly, sea water was available in its nearby harbour and lastly, it was easy to move pipes and pump equipment as the transport system by sea and road was good. (Richard & James, 1983) The entire operation cost

8625-453: The levels of sodium and chloride in the blood within a very narrow range around 9 g/L (0.9% by mass). In most open waters concentrations vary somewhat around typical values of about 3.5%, far higher than the body can tolerate and most beyond what the kidney can process. A point frequently overlooked in claims that the kidney can excrete NaCl in Baltic concentrations of 2% (in arguments to

8740-539: The main types of phytoplankton are diatoms which is the primary food source of Antarctic krill . As the cycle continues, various larger sea animals feed off of Antarctic krill, but since there is a shortage of iron from the initial phytoplankton/diatoms, then these larger species also lack iron. The larger sea animals include Baleen Whales such as the Blue Whale and Fin Whale . These whales not only rely on iron for

8855-432: The mainland. These settlers gave the islands their name, Britain and Ireland being west of mainland Scandinavia . Although plagued by poor water supplies and piracy during much of its history, Heimaey became the most important center of the Icelandic fishing industry, having one of the few good harbors on the southern side of the country, and being situated in very rich fishing grounds. At about 20:00 on 21 January 1973,

8970-431: The manufacturing of MOX fuel as economically unviable. In order for seawater mineral and element extractions to take place while taking close consideration of sustainable practices, it is necessary for monitored management systems to be put in place. This requires management of ocean areas and their conditions, environmental planning , structured guidelines to ensure that extractions are controlled, regular assessments of

9085-440: The middle of March. The decline was slower after that, but by the middle of April the flow rate had fallen to about 5 m /s (180 cu ft/s). Short-lived submarine activity was discovered by a fishing vessel on 26 May, about four kilometres (two nautical miles) northeast of Heimaey and 1 km ( 1 ⁄ 2  nmi) off the coast of the mainland. The eruption finally came to an end in early July, when flowing lava

9200-401: The most striking features of this is ocean acidification , resulting from increased CO 2 uptake of the oceans related to higher atmospheric concentration of CO 2 and higher temperatures, because it severely affects coral reefs , mollusks , echinoderms and crustaceans (see coral bleaching ). Seawater is a means of transportation throughout the world. Every day plenty of ships cross

9315-639: The negative effects of drinking seawater when dehydrated. The temptation to drink seawater was greatest for sailors who had expended their supply of fresh water and were unable to capture enough rainwater for drinking. This frustration was described famously by a line from Samuel Taylor Coleridge 's The Rime of the Ancient Mariner : Water, water, everywhere, And all the boards did shrink; Water, water, everywhere, Nor any drop to drink. Although humans cannot survive on seawater in place of normal drinking water, some people claim that up to two cups

9430-429: The northern half of the island and adding to the cone until it was 200 metres (660 ft) high. The eruption column that caused the air fall "occasionally rose to 9,000 metres (30,000 ft), or nearly to the tropopause ". Lava flows from the cone traveled north and east to produce a "continuously expanding lava delta " along the east coast of the island and into the harbor, where small explosions built up

9545-462: The ocean and its ecosystem's food cycle. For example, the Southern Ocean contributes greatly to the environmental carbon cycle . Given that this body of water does not contain high levels of iron , the deficiency impacts the marine life living in its waters. As a result, this ocean is not able to produce as much phytoplankton which hinders the first source of the marine food chain. One of

9660-496: The ocean could heighten the amount of iron in seawater through their excretions which would promote a better ecosystem. Krill and baleen whales act as large iron reservoirs in seawater in the Southern Ocean. Krill can retain up to 24% of iron found on surface waters within its range. The process of krill feeding on diatoms releases iron into seawater, highlighting them as an important part of the ocean's iron cycle . The advantageous relationship between krill and baleen whales increases

9775-415: The ocean floor when the ocean formed. The presence of salt's other dominant ion, chloride, results from outgassing of chloride (as hydrochloric acid ) with other gases from Earth's interior via volcanos and hydrothermal vents . The sodium and chloride ions subsequently became the most abundant constituents of sea salt. Ocean salinity has been stable for billions of years, most likely as a consequence of

9890-459: The ocean to deliver goods to various locations around the world. Seawater is a tool for countries to efficiently participate in international commercial trade and transportation, but each ship exhausts emissions that can harm marine life, air quality of coastal areas. Seawater transportation is one of the fastest growing human generated greenhouse gas emissions. The emissions released from ships pose significant risks to human health in nearing areas as

10005-416: The ocean's biomass , clearly playing an important part in oceanic processes. In 2000 sediments from the ocean floor revealed a species of Archaea that breaks down methane , an important greenhouse gas and a major contributor to atmospheric warming. Some bacteria break down the rocks of the sea floor, influencing seawater chemistry. Oil spills, and runoff containing human sewage and chemical pollutants have

10120-876: The overall productivity in marine ecosystems as well as increasing iron levels in seawater would allow for a balanced and productive system for the ocean. However, a more in depth study is required to understand the benefits of whale feces as a fertilizer and to provide further insight in iron recycling in the Southern Ocean. Projects on the management of ecosystems and conservation are vital for advancing knowledge of marine ecology. Like any mineral extraction practices, there are environmental advantages and disadvantages. Cobalt and Lithium are two key metals that can be used for aiding with more environmentally friendly technologies above ground, such as powering batteries that energize electric vehicles or creating wind power . An environmentally friendly approach to mining that allows for more sustainability would be to extract these metals from

10235-467: The pre-eruption population had returned to the island, and by March 1975, about 80% had returned. The recovery and reconstruction of Heimaey was paid for by all Icelanders via a hypothecated sales tax , as well as through international aid totalling US$ 2.1 million primarily from Denmark but with substantial contributions from the United States and several international organisations. With

10350-460: The pumping crews on where to direct their efforts to most efficiently slow the flows. Eventually the Wanderer broke up into two pieces which both stopped approximately 100 metres (330 ft) from the harbour mouth. The ensuing lava-cooling operations were the most ambitious that had ever been undertaken. Sandey was able to spray up to 400 litres per second (105 US gallons per second) onto

10465-471: The rest of the island, causing extensive property damage. Many houses were destroyed by the weight of the ash fall, but crews of volunteers working to clear the ash from roofs and board up windows saved many more. By the end of January, tephra covered most of the island, reaching 5 metres (16 ft) deep in places. Apart from falling ash, some houses were also burned down by fires caused by lava bombs , or overridden by advancing lava flows. By early February,

10580-508: The sea by rivers after rainfall washed it out of the ground. Upon reaching the ocean, these salts concentrated as more salt arrived over time (see Hydrologic cycle ). Halley noted that most lakes that do not have ocean outlets (such as the Dead Sea and the Caspian Sea , see endorheic basin ), have high salt content. Halley termed this process "continental weathering". Halley's theory was partly correct. In addition, sodium leached out of

10695-421: The seafloor. Lithium mining from the seafloor at mass quantities could provide a substantial amount of renewable metals to promote more environmentally friendly practices in society to reduce humans' carbon footprint . Lithium mining from the seafloor could be successful, but its success would be dependent on more productive recycling practices above ground. There are also risks that come with extracting from

10810-409: The seafloor. Many biodiverse species have long lifespans on the seafloor, which means that their reproduction takes more time. Similarly to fish harvesting from the seafloor, the extraction of minerals in large amounts, too quickly, without proper protocols, can result in a disruption of the underwater ecosystems. Contrarily, this would have the opposite effect and prevent mineral extractions from being

10925-411: The seawater is taken along with a larger quantity of fresh water. However, drinking seawater to maintain hydration is counterproductive; more water must be excreted to eliminate the salt (via urine ) than the amount of water obtained from the seawater itself. In normal circumstances, it would be considered ill-advised to consume large amounts of unfiltered seawater. The renal system actively regulates

11040-428: The situation by fire engines sounding their sirens, and gathered by the harbour with just the small amount of possessions they were able to carry. The first boats left for Þorlákshöfn at about 02:30, just half an hour after the start of the eruption. Most of the population left the island by boat. Fortunately, the lava flows and tephra fall did not at first affect the island's airstrip ( Vestmannaeyjar Airport ), and

11155-424: The steam to lay more pipes. The workers dubbed themselves 'The Suicide Squad', and managed to lay pipes up to 130 metres (430 ft) inward from the flow front, directly over the advance. Although several men sustained minor burns, no serious injuries were received. By the end of March, a fifth of the town had been covered by lava flows, and increased pumping capacity was required. Thirty-two pumps, each with

11270-562: The surface of oceans in pre-industrial time (before 1850) was around 8.2. Since then, it has been decreasing due to a human-caused process called ocean acidification that is related to carbon dioxide emissions : Between 1950 and 2020, the average pH of the ocean surface fell from approximately 8.15 to 8.05. The pH value of seawater is naturally as low as 7.8 in deep ocean waters as a result of degradation of organic matter in these waters. It can be as high as 8.4 in surface waters in areas of high biological productivity . Measurement of pH

11385-497: The town, and the digging of a trench to channel away the CO 2 (carbon dioxide) . These defences were only partially effective, as they relied on the assumption that the gases were produced at the vent, and flowed into the town from there. It is believed that as least some of the CO 2 originated deep within the volcanic conduit and percolated through older volcanic rocks, rising directly into

11500-700: The town. The possibility of lava flows cutting off the harbour was the most significant threat facing the town. One contingency plan devised, should the harbour be closed off, was to cut through a low sand spit on the north side of the island to provide a new channel into the harbour, but it was hoped that if the lava flow could be slowed, this would not be necessary. Lava flows had been sprayed with water in attempts to slow them in Hawaii and on Mount Etna , but these had been rather small-scale operations with limited success. However, Professor Þorbjörn Sigurgeirsson carried out an experiment that proved that further advances of

11615-455: The two methods is well known in this and other fields. In the 1990s, improved techniques of detection and identification of microbes by probing just small snippets of DNA , enabled researchers taking part in the Census of Marine Life to identify thousands of previously unknown microbes usually present only in small numbers. This revealed a far greater diversity than previously suspected, so that

11730-419: The unconsolidated gravelly tephra as well as wind erosion . The islanders have planted grass around the lower slopes of the otherwise bare hill, to stabilise it against further erosion, and eventually it is expected that most of the volcano will be covered by grass, as neighbouring Helgafell is. Sea water Seawater , or sea water , is water from a sea or ocean . On average, seawater in

11845-418: The very low thermal conductivity of rock. Following the end of the eruption, scientists began to assess the feasibility of extracting geothermal heat from the gradually cooling flows. Experimental heating systems were soon devised, and by 1974 the first house was connected. The scheme was extended to several more houses and the hospital, and in 1979 construction began of four larger plants to extract heat from

11960-419: The volume of lava and tephra emitted during the five-month eruption was estimated to be about 0.25 km (330,000,000 cu yd). About 2.5 km (1 sq mi) of new land was added to the island, increasing its pre-eruption area by some 20%. In the end, the harbour entrance was narrowed considerably but not closed off, and the new lava flow acted as a breakwater, improving the shelter afforded by

12075-407: The whole fissure, which reached a maximum length of about 3 kilometres (1.9 mi) during the first few hours of the eruption, but activity soon became concentrated on one vent, about 0.8-kilometre (0.50 mi) north of the old volcanic cone of Helgafell and just outside the eastern edge of the town. During the early days of the eruption, the rate of lava and tephra emission from the fissure

12190-470: The world traditionally incorporate seawater directly as an ingredient, cooking other ingredients in a diluted solution of filtered seawater as a substitute for conventional dry seasonings . Proponents include world-renowned chefs Ferran Adrià and Quique Dacosta , whose home country of Spain has six different companies sourcing filtered seawater for culinary use. The water is marketed as la sal perfecta , "the perfect salt", containing less sodium with what

12305-466: The world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximately 35 grams (1.2 oz) of dissolved salts (predominantly sodium ( Na ) and chloride ( Cl ) ions ). The average density at the surface is 1.025 kg/L. Seawater is denser than both fresh water and pure water (density 1.0 kg/L at 4 °C (39 °F)) because

12420-437: Was as much as 100 m (110 yd) thick. The flow carried off large blocks from the main cone that had broken off, as well as volcanic bombs. "The viscosity of the lava fragments ejected by the blasts was, for basalt, relatively high. Very little spatter was produced and scoria bombs sometimes broke up explosively in flight (presumably due to rapid vesiculation ), and by rapid impact on landing." The high viscosity led to

12535-548: Was estimated to be 100 cubic metres per second (3,500 cubic feet per second), and within two days, the lava fountains had built a cinder cone over 100 metres (330 ft) high. The name initially given to the new volcano was Kirkjufell ( Church Mountain ), owing to its proximity to Kirkjubær. This name was not adopted by the official Icelandic place-naming committee, who chose Eldfell ( Fire Mountain ) instead, despite local opposition. The fountains' Strombolian eruptions continued until 19 February, depositing thick tephra over

12650-483: Was in dock. The encroaching lava flow threatened to destroy the harbour. The eruption lasted until 3 July. Icelanders sprayed the lava with six million tons of cold seawater, causing some to solidify and much to be diverted, thus saving the harbour. During the eruption, half of the town was crushed and the island expanded in length. The eruption increased the area of Heimaey from 11.2 km (4.3 sq mi) to 13.44 km (5.19 sq mi). Only one man died in

12765-405: Was necessary because lava flows were already moving slowly into the eastern side of town, and the whole of the small island was threatened by the likelihood of heavy ash fall. Because of severe storms in the days before the eruption, almost the entire fishing fleet was in the harbour, a stroke of luck which greatly assisted the organisation of the rapid evacuation. The population was alerted to

12880-399: Was no longer visible, although subsurface flows may have continued for a few days longer. Shortly before the end of the eruption, a tiltmeter 1,150 m (3,770 ft) from the crater which had been measuring ground deformation throughout the eruption detected subsidence towards the crater, implying that the shallow magma chamber which had fed the eruption was emptying out. In total,

12995-518: Was responsible for some 3% of Iceland's GNP, the effect on the whole country's economy would be significant. Efforts to prevent the loss of the harbour are described further below. Lava flows also moved into the sea east of the island, creating new land that would eventually add over two square kilometres ( 3 ⁄ 4  sq mi) to the island, and into the eastern parts of town, destroying several hundred houses. The flows were thick and blocky ʻaʻā lava (Icelandic: apalhraun ) flows, and covered

13110-700: Was taken by the pirates from her home at Stakkagerði on Heimaey to the slave market in Algeria . She was eventually ransomed back to Denmark by King Christian IV of Denmark and was re-educated by and later married the poet Hallgrímur Pétursson . The Hallgrímskirkja Lutheran church in Reykjavík is named in his honour. At 01:00 on 23 January 1973, a volcanic eruption of the mountain Eldfell began on Heimaey. The ground on Heimaey started to quake and fissures formed. The fissures grew to 1,600 metres (5,200 ft) in length, and lava began to erupt. Lava sprayed into

13225-425: Was the "Practical Salinity Scale" where salinity was measured in "practical salinity units (PSU)". The current standard for salinity is the "Reference Salinity" scale with the salinity expressed in units of "g/kg". The density of surface seawater ranges from about 1020 to 1029 kg/m , depending on the temperature and salinity. At a temperature of 25 °C, the salinity of 35 g/kg and 1 atm pressure,

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