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96-614: The town extends approximately 11 kilometers north to south and 9 kilometers east to west, and is located on the coast of the Seto Inland Sea in southeastern Yamaguchi Prefecture. Parts of the town are within the borders of the Setonaikai National Park . Yamaguchi Prefecture Hirao has a humid subtropical climate ( Köppen climate classification Cfa ) with very warm summers and cool winters. The average annual temperature in Hirao

192-562: A HAB alert for Newman Lake following tests showing potentially harmful toxicity levels for cyanobacteria, while in the same month record-high levels of microcystins were reported leading to an extended 'Do Not Drink' advisory for 280 households at Clear Lake , California's second-largest freshwater lake. Water conditions in Florida, meanwhile, continue to deteriorate under increasing nutrient inflows, causing severe HAB events in both freshwater and marine areas. HABs also cause harm by blocking

288-521: A HAB event may cause asthma attacks or lead to other respiratory ailments. In 2018 agricultural officials in Utah worried that even crops could become contaminated if irrigated with toxic water, although they admit that they can't measure contamination accurately because of so many variables in farming. They issued warnings to residents, however, out of caution. Persons are generally warned not to enter or drink water from algal blooms, or let their pets swim in

384-432: A bloom nearby is not recommended. Potent toxins are accumulated in shellfish that feed on the algae. If the shellfish are consumed, various types of poisoning may result. These include amnesic shellfish poisoning (ASP), diarrhetic shellfish poisoning , neurotoxic shellfish poisoning , and paralytic shellfish poisoning . A 2002 study has shown that algal toxins may be the cause for as many as 60,000 intoxication cases in

480-402: A bloom reduces oxygen saturation during the night by respiration. And when the algae eventually die off, the microbes which decompose the dead algae use up even more oxygen, which in turn causes more fish to die or leave the area. When oxygen continues to be depleted by blooms it can lead to hypoxic dead zones , where neither fish nor plants are able to survive. These dead zones in the case of

576-424: A concentration of 1,000 algae cells/ml, while in dense blooms they can measure over 200,000/ml. Diatoms produce domoic acid , another neurotoxin, which can cause seizures in higher vertebrates and birds as it concentrates up the food chain. Domoic acid readily accumulates in the bodies of shellfish , sardines , and anchovies , which if then eaten by sea lions , otters , cetaceans , birds or people, can affect

672-713: A cruise on the Setuchi. The eastern end of the Sea is now famous for the Setouchi Triennale set up in 2010 with the next event happening in 2022. Some of this takes place on the island of Naoshima , known colloquially as the art island, and the home of several permanent museums. At the far eastern extremity, as the Sea meets the Pacific Ocean, are the Naruto whirlpools that can be reached by sight-seeing boats. The Shiwaku Islands are

768-459: A cyanobacteria-dominated system characterized by seasonal HABs. As more wastewater treatment infrastructure is built, more treated wastewater is returned to the natural water system, leading to a significant increase in these residual nutrients. Residual nutrients combine with nutrients from other sources to increase the sediment nutrient stockpile that is the driving force behind phase shifts to entrenched eutrophic conditions. This contributes to

864-471: A defined group numbering 28 that can be reached by ferry boat from Marugame . Here Richard Henry Brunton built one of his lighthouses that can still be seen, and the grave of Frank Toovey Lake , a young midshipman in his survey party has become famous. In the central area of Seto Inland Sea is Mount Ishizuchi on Shikoku . It is the highest mountain in western Japan and the highest mountain in Shikoku . In

960-455: A different location. Australia in 2016 also had to cut off water to farmers. Alan Steinman of Grand Valley State University has explained that among the major causes for the algal blooms in general, and Lake Erie specifically, is because blue-green algae thrive with high nutrients, along with warm and calm water. Lake Erie is more prone to blooms because it has a high nutrient level and is shallow, which causes it to warm up more quickly during

1056-687: A directly elected mayor and a unicameral town council of 12 members. Hirao, together with the towns of Kaminoseki and Tabuse contributes one member to the Yamaguchi Prefectural Assembly. In terms of national politics, the town is part of the Yamaguchi 2nd district of the lower house of the Diet of Japan . Hirao has a rural economy based on agriculture and commercial fishing. There is one small industrial park . Hirao has two public elementary schools and one public junior high school operated by

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1152-543: A factor, since phytoplankton can grow at different rates depending on the relative abundance of these substances (e.g. ammonia , urea , nitrate ion). A variety of other nutrient sources can also play an important role in affecting algal bloom formation, including iron, silica or carbon. Coastal water pollution produced by humans (including iron fertilization) and systematic increase in sea water temperature have also been suggested as possible contributing factors in HABs. Among

1248-527: A few days to many months. After the bloom dies, the microbes that decompose the dead algae use up more of the oxygen, generating a " dead zone " which can cause fish die-offs . When these zones cover a large area for an extended period of time, neither fish nor plants are able to survive. Harmful algal blooms in marine environments are often called "red tides". It is sometimes unclear what causes specific HABs as their occurrence in some locations appears to be entirely natural, while in others they appear to be

1344-509: A few decades. After a 2014 HAB incident in Monterey Bay , California, health officials warned people not to eat certain parts of anchovy, sardines, or crab caught in the bay. In 2015 most shellfish fisheries in Washington, Oregon and California were shut down because of high concentrations of toxic domoic acid in shellfish. People have been warned that inhaling vapors from waves or wind during

1440-409: A foam, scum, or mat on or just below the surface of water and can take on various colors depending on their pigments. Cyanobacteria blooms in freshwater lakes or rivers may appear bright green, often with surface streaks that look like floating paint. Cyanobacterial blooms are a global problem. Most blooms occur in warm waters with excessive nutrients. The harmful effects from such blooms are due to

1536-603: A local seaport on the Seto Inland Sea, and some of them were actually built. The Ministry of Railroads, later the Japanese National Railways and then Shikoku Railway Company , ran some train ferry lines between Honshū and Shikoku including the line between Uno Station (Tamano) and Takamatsu Station (Takamatsu). When the Great Seto Bridge was finished and began to serve the two coastal areas, that ferry line

1632-512: A main transport line between its coastal areas, including what is today the Kansai region and Kyushu . It was also a main transport line between Japan and other countries, including Korea and China. Even after the creation of major highways such as the Nankaidō and San'yōdō , the Seto Inland Sea remained a major transport route. There are records that some foreign emissaries from China and Korea sailed on

1728-428: A natural result of the movement of certain ocean currents) while in others they appear to be a result of increased nutrient pollution from human activities. The growth of marine phytoplankton is generally limited by the availability of nitrates and phosphates , which can be abundant in agricultural run-off as well as coastal upwelling zones. Other factors such as iron-rich dust influx from large desert areas such as

1824-563: A number of smaller ones that pass between islands or connect the Seto Inland Sea to other seas or the Pacific . Almost 3,000 islands are located in the Seto Inland Sea. The largest island is Awaji-shima , and the second largest is Shōdo-shima . Many of the smaller islands are uninhabited. Over 500 marine species are known to live in the Seto Inland Sea. Examples are the ayu , an amphidromous fish, horseshoe crab , finless porpoise , and great white shark , which has occasionally attacked people in

1920-498: A part of Hiroshima Prefecture ) clans were two of the more famous suigun lords. In the 12th century, Taira no Kiyomori planned to move the capital from Kyoto to the coastal village of Fukuhara (today Kobe ) to promote trade between Japan and the Song dynasty of China. This transfer was unsuccessful, and soon after Kyoto became the capital again. Later, the Battle of Yashima took place off

2016-615: A part of Kobe ) and Akashi for two years. In medieval literature, because of the Genpei War , the Seto Inland Sea is one of the important backgrounds of The Tale of the Heike , particularly in its latter part. In the Western world, Donald Richie wrote a literary nonfiction travelogue called The Inland Sea relating a journey along the sea, beginning from the East at Himeji and ending at Miyajima in

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2112-453: A part of Wakayama Prefecture , was appointed the Setonaikai National Park ( 瀬戸内海国立公園 , Setonaikai Kokuritsu kōen ) on March 16, 1934, as one of three oldest national parks in Japan. Itsukushima Shrine , on the island of Itsukushima in the city of Hatsukaichi , is a UNESCO World Heritage Site and one of the most famous Japanese sites outside Tokyo and Kyoto . Shōdoshima , nicknamed

2208-415: A predictable seasonal occurrence resulting from coastal upwelling, a natural result of the movement of certain ocean currents. The growth of marine phytoplankton (both non-toxic and toxic) is generally limited by the availability of nitrates and phosphates, which can be abundant in coastal upwelling zones as well as in agricultural run-off. The type of nitrates and phosphates available in the system are also

2304-655: A result of human activities. In certain locations there are links to particular drivers like nutrients, but HABs have also been occurring since before humans started to affect the environment. HABs are induced by eutrophication , which is an overabundance of nutrients in the water. The two most common nutrients are fixed nitrogen ( nitrates , ammonia , and urea ) and phosphate . The excess nutrients are emitted by agriculture , industrial pollution, excessive fertilizer use in urban/suburban areas, and associated urban runoff . Higher water temperature and low circulation also contribute. HABs can cause significant harm to animals,

2400-399: A status report. While no particular cause of HABs has been found, many different factors can contribute to their presence. These factors can include water pollution , which originates from sources such as human sewage and agricultural runoff . The occurrence of HABs in some locations appears to be entirely natural (algal blooms are a seasonal occurrence resulting from coastal upwelling,

2496-604: Is 105 m (344 ft). Hydrologically, Seto Inland Sea is not a true inland sea , being neither an epeiric body of water like Hudson Bay nor an isolated endorheic basin like the Caspian Sea . Rather, it is actually a marginal sea : a division of a wider ocean (in this case the Pacific) which is partially enclosed by islands, archipelagos, or peninsulas (here, the Japanese Home Islands), adjacent to or widely open to

2592-549: Is 16.0 °C. The average annual rainfall is 1678 mm with September as the wettest month. The temperatures are highest on average in July, at around 26.2 °C, and lowest in January, at around 6.6 °C. Per Japanese census data, the population of Hirao has been steady for the past 50 years. The area of Hirao was part of an ancient Suō Province . During the Edo Period , the area

2688-546: Is a natural phenomenon, but the exact cause or combination of factors that result in a HAB event are not necessarily known. However, three key natural factors are thought to play an important role in a bloom - salinity, temperature, and wind. HABs cause economic harm, so outbreaks are carefully monitored. For example, the Florida Fish and Wildlife Conservation Commission provides an up-to-date status report on HABs in Florida. The Texas Parks and Wildlife Department also provides

2784-445: Is an algal bloom that causes negative impacts to other organisms by production of natural algae-produced toxins , water deoxygenation , mechanical damage to other organisms, or by other means. HABs are sometimes defined as only those algal blooms that produce toxins, and sometimes as any algal bloom that can result in severely lower oxygen levels in natural waters, killing organisms in marine or fresh waters . Blooms can last from

2880-809: Is causing algal blooms to form in places previously considered "impossible" or rare for them to exist, such as under the ice sheets in the Arctic , in Antarctica , the Himalayan Mountains , the Rocky Mountains , and in the Sierra Nevada Mountains . In the U.S., every coastal state has had harmful algal blooms over the last decade and new species have emerged in new locations that were not previously known to have caused problems. Inland, major rivers have seen an increase in their size and frequency. In 2015

2976-399: Is derived from blooms of any of several species of dinoflagellate , such as Karenia brevis . However, the term is misleading since algal blooms can widely vary in color, and growth of algae is unrelated to the tides . Not all red tides are produced by dinoflagellates. The mixotrophic ciliate Mesodinium rubrum produces non-toxic blooms coloured deep red by chloroplasts it obtains from

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3072-498: Is known for its moderate climate, with a stable year-round temperature and relatively low rainfall levels. The sea is famous for its periodic red tides ( 赤潮 , akashio ) caused by dense groupings of certain phytoplankton that result in the death of large numbers of fish. Since the 1980s, the sea's northern and southern shores have been connected by the three routes of the Honshū–Shikoku Bridge Project , including

3168-474: Is not sufficient to tell the difference between toxic and non-toxic populations. In these cases, tools can be employed to measure the toxin level or to determine if the toxin-production genes are present. In a narrow definition, harmful algal blooms are only those blooms that release toxins that affect other species. On the other hand, any algal bloom can cause dead zones due to low oxygen levels , and could therefore be called "harmful" in that sense. The usage of

3264-481: Is sometimes unclear what causes specific HABs as their occurrence in some locations appears to be entirely natural, while in others they appear to be a result of human activities. Furthermore, there are many different species of algae that can form HABs, each with different environmental requirements for optimal growth. The frequency and severity of HABs in some parts of the world have been linked to increased nutrient loading from human activities. In other areas, HABs are

3360-563: The Akashi Kaikyo Bridge (the second-longest suspension bridge in the world) to Awaji Island , from there via the Ōnaruto Bridge to Ōge-jima ( Naruto , Tokushima Prefecture ) beyond the 1.3-kilometer wide Naruto Strait and finally across the Muya Bridge to Shikoku . The Great Seto Bridge connects Okayama Prefecture with Kagawa Prefecture since 1988. It consists of a total of six two-storey bridges, whose lower floors are used by

3456-646: The Great Seto Bridge , which serves both railroad and automobile traffic. The International Hydrographic Organization 's definition of the limits of the Seto Inland Sea (published in 1953) is as follows: On the West. The southeastern limit of the Japan Sea [In Shimonoseki-kaikyo . A line running from Nagoya Saki (130°49'E) in Kyûsû through the islands of Uma Sima and Muture Simia (33°58',5N) to Murasaki Hana (34°01'N) in Honsyû ]. On

3552-646: The Inland Sea , is the body of water separating Honshu , Shikoku , and Kyushu , three of the four main islands of Japan . It serves as a waterway connecting the Pacific Ocean to the Sea of Japan . It connects to Osaka Bay and provides a sea transport link to industrial centers in the Kansai region , including Osaka and Kobe . Before the construction of the San'yō Main Line , it was

3648-517: The Ohio River had a bloom which stretched an "unprecedented" 650 miles (1,050 km) into adjoining states and tested positive for toxins, which created drinking water and recreation problems. A portion of Utah's Jordan River was closed due to toxic algal bloom in 2016. Off the west coast of South Africa , HABs caused by Alexandrium catanella occur every spring. These blooms of organisms cause severe disruptions in fisheries of these waters as

3744-495: The US Environmental Protection Agency in 2008 who stated that HABs include "potentially toxic (auxotrophic, heterotrophic) species and high-biomass producers that can cause hypoxia and anoxia and indiscriminate mortalities of marine life after reaching dense concentrations, whether or not toxins are produced". Harmful algal bloom in coastal areas are also often referred to as "red tides". The term "red tide"

3840-565: The "island of olives", and the Naruto whirlpools are two other well-known tourist sites. Neighboring locations like Kotohira and Okayama are often combined with the tour of the Setouchi region. Some historic sites, including Yashima in Takamatsu and Kurashiki , also attract many visitors. Hiroshima is the neighbor city to Itsukushima Shrine and another UNESCO World Heritage Site because of atomic bomb damage in 1945. Idol Unit STU48 operate on

3936-441: The 1980s. The is the result of human induced factors such as increased nutrient inputs ( nutrient pollution ) and climate change (in particular the warming of water temperatures). The parameters that affect the formation of HABs are ocean warming , marine heatwaves, oxygen loss , eutrophication and water pollution . HABs contain dense concentrations of organisms and appear as discolored water, often reddish-brown in color. It

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4032-528: The Chesapeake Bay, where they are a normal occurrence, are also suspected of being a major source of methane . Scientists have found that HABs were a prominent feature of previous mass extinction events , including the End-Permian Extinction . Tests have shown some toxins near blooms can be in the air and thereby be inhaled, which could affect health. Eating fish or shellfish from lakes with

4128-738: The East ( Kii Suidô ). A line running from Takura Saki (34°16'N) in Honsyû to Oishi Hana in the island of Awazi , through this island to Sio Saki (34°11'N) and on to Oiso Saki in Sikoku . On the South ( Bungo Suidô ). A line joining Sada Misaki (33°20'N) in Sikoku and Seki Saki in Kyûsyû. The range of the Seto Inland Sea by the Territorial Sea Law ( 領海及び接続水域に関する法律 ) is 19,700 km (7,600 sq mi). The range of

4224-463: The Gulf of Mexico were witnessed in the early 1500s by explorer Cabeza de Vaca , it is unclear what initiates these blooms and how large a role n anthropogenic and natural factors play in their development. The number of reported harmful algal blooms (cyanobacterial) has been increasing throughout the world. It is unclear whether the apparent increase in frequency and severity of HABs in various parts of

4320-519: The Pacific. Development of land transportation shifted the travel between east and west — that is, between Honshū and Kyūshū — to railroad and road transport. Two coastal railways, San'yō Main Line in Honshū and Yosan Main Line, were built. Those railway lines stimulated the local economy and once invoked a rail mania. Many short railroads were planned to connect a certain station of those two lines and

4416-717: The Sahara Desert are thought to play a major role in causing HAB events. Some algal blooms on the Pacific Coast have also been linked to occurrences of large-scale climatic oscillations such as El Niño events. Other factors such as iron-rich dust influx from large desert areas such as the Sahara are thought to play a role in causing HABs. Some algal blooms on the Pacific coast have also been linked to natural occurrences of large-scale climatic oscillations such as El Niño events. HABs are also linked to heavy rainfall. Although HABs in

4512-528: The Seto Inland Sea according to the Setouchi Law and the Setouchi Law Enforcement Order is 21,827 km (8,427 sq mi). The Seto Inland Sea is 450 km (280 mi) long from east to west. The width from south to north varies from 15 to 55 km (10 to 34 mi). In most places, the water is relatively shallow. The average depth is 38 m (125 ft); the greatest depth

4608-445: The Seto Inland Sea as transport line served four coastal areas: Kansai, Chūgoku, Shikoku, and eastern Kyūshū. The Seto Inland Sea provided each of these regions with local transportation and connected each region to the others and far areas, including the coastal area of the Sea of Japan, Korea, and China. After Kobe port was founded in 1868 to serve foreign ships, the Seto Inland Sea became a major international waterway with connection to

4704-415: The Seto Inland Sea is one of the most famous tourist destinations in Japan. Even before Japan opened to foreigners in the middle of the 19th century, the sea's beauty was praised and introduced to the Western world by those who visited Japan, including Philipp Franz von Siebold , and after the country's opening, Ferdinand von Richthofen and Thomas Cook . Its coastal area, except for Osaka Prefecture and

4800-632: The Seto Inland Sea. The importance of water traffic gave rise to private navies in the region. In many documents, these navies were called suigun ( 水軍 , "water army") , or simply pirates. Sometimes they were considered to be public enemies, but in most cases they were granted the right to self-governance as a result of their strength. During the feudal period, suigun seized power in most coastal areas. The Kono in Iyo Province (today Ehime Prefecture ) and Kobayakawa (later Mōri ) in Aki Province (today

4896-466: The Seto Inland Sea. In the past, whales entered the sea to feed or breed, however because of whaling and pollution, they are rarely seen. During the last ice age , the sea level was lower than today. After the ice age, sea water poured into a basin between the Chūgoku mountains and Shikoku mountains and formed the Seto Inland Sea as it is known today. From ancient times, the Seto Inland Sea served as

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4992-484: The West, close to Hiroshima, going from island to island, exploring the landscape, meeting and discussing with local people, as well as musing on Japanese culture, the nature of travel and of identity, and his own personal sense of identity. In 1991, filmmakers Lucille Carra and Brian Cotnoir produced a film version of Richie's book, which further explored the region through interviews and images photographed by Hiro Narita. Produced by Travelfilm Company and adapted by Carra,

5088-529: The algae bloom (such as rapid termination of the HAB as cells convert from the pelagic state to the benthic state). Many of the algal species that undergo this dual-stage life cycle are capable of rapid vertical migration. This migration is required for the movement from the benthic area of bodies of water to the pelagic zone. These species require immense amounts of energy as they pass through the various thermoclines , haloclines , and pycnoclines that are associated with

5184-523: The algae it eats.  As a technical term, it is being replaced in favor of more precise terminology, including the generic term "harmful algal bloom" for harmful species, and " algal bloom " for benign species. There are three main types of phytoplankton which can form into harmful algal blooms: cyanobacteria , dinoflagellates , and diatoms . All three are made up of microscopic floating organisms which, like plants, can create their own food from sunlight by means of photosynthesis . That ability makes

5280-403: The base of the food web upon which nearly all other marine organisms depend. Of the 5000+ species of marine phytoplankton that exist worldwide, about 2% are known to be harmful or toxic. Blooms of harmful algae can have large and varied impacts on marine ecosystems, depending on the species involved, the environment where they are found, and the mechanism by which they exert negative effects. It

5376-649: The bodies of water in which these cells exist. The other types of algae are diatoms and dinoflagellates , found primarily in marine environments, such as ocean coastlines or bays, where they can also form algal blooms. Coastal HABs are a natural phenomenon, although in many instances, particularly when they form close to coastlines or in estuaries, it has been shown that they are exacerbated by human-induced eutrophication and / or climate change. They can occur when warmer water, salinity, and nutrients reach certain levels, which then stimulates their growth. Most HAB algae are dinoflagellates. They are visible in water at

5472-585: The bottom of this sea known as the Seto Inland Sea Mir. Author and literary critic Amy Chavez's The Widow, the Priest and the Octopus Hunter: Discovering a Lost Way of Life on a Secluded Japanese Island is an account of the author's firsthand experience living among and interacting with the residents of Shiraishi. Red tide A harmful algal bloom ( HAB ), or excessive algae growth ,

5568-504: The causes of algal blooms are: Nutrients enter freshwater or marine environments as surface runoff from agricultural pollution and urban runoff from fertilized lawns, golf courses and other landscaped properties; and from sewage treatment plants that lack nutrient control systems. Additional nutrients are introduced from atmospheric pollution. Coastal areas worldwide, especially wetlands and estuaries, coral reefs and swamps, are prone to being overloaded with those nutrients. Most of

5664-415: The city of Toledo, Ohio advised its 500,000 residents to not drink tap water as the high toxin level from an algal bloom in western Lake Erie had affected their water treatment plant's ability to treat the water to a safe level. The emergency required using bottled water for all normal uses except showering, which seriously affected public services and commercial businesses. The bloom returned in 2015 and

5760-521: The coast of present-day Takamatsu. In the Edo period , the Seto Inland Sea was one of the busiest transport lines in Japan. It was a part of a navigational route around Japan's islands via the Sea of Japan. Many ships navigated from its coastal areas to the area along the Sea of Japan. Major ports in the Edo period were Osaka, Sakai, Shimotsui, Ushimado , and Tomonoura. The Seto Inland Sea also served many daimyōs in

5856-682: The coast of the Seto Inland Sea include Osaka, Kobe, and Hiroshima. Smaller scale manufacturing and industry can also be found in Kurashiki , Kure , Fukuyama , and Ube in Honshū, and Sakaide , Imabari , and Niihama in Shikoku. Major industries include steel production, vehicle manufacture, ship building, textiles, and since the 1960s, oil refining and chemical products. Imabari Shipbuilding , Japan's largest ship building company, has its headquarters and some of its yards in Imabari, Ehime Prefecture. Thanks to

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5952-575: The environment and economies. They have been increasing in size and frequency worldwide, a fact that many experts attribute to global climate change . The U.S. National Oceanic and Atmospheric Administration (NOAA) predicts more harmful blooms in the Pacific Ocean . Potential remedies include chemical treatment, additional reservoirs, sensors and monitoring devices, reducing nutrient runoff, research and management as well as monitoring and reporting. Terrestrial runoff, containing fertilizer, sewage and livestock wastes, transports abundant nutrients to

6048-704: The film won numerous awards, including Best Documentary at the Hawaii International Film Festival (1991) and the Earthwatch Film Award. It screened at the Sundance Film Festival in 1992. Koushun Takami 's novel Battle Royale took place on a fictional island in the Seto Inland Sea. A critical plot element of the Japanese series Fafner in the Azure is an alien life form discovered at

6144-450: The great lakes, but are also prone to bodies of salt water as well. Many of the species that form harmful algae blooms will undergo a dual-stage life system. These species will alternate between a benthic resting stage and a pelagic vegetative state. The benthic resting stage corresponds to when these species are resting near the ocean floor. In this stage, the species cells are waiting for optimal conditions so that they can move towards

6240-665: The importance of the Seto Inland Sea as a transport line. Remarkable land transportation innovations include the San'yō Main Railroad Line in Honshū and the Yosan Main Railroad Line in Shikoku (both completed before World War II ) and three series of bridges connecting Honshū and Shikoku (completed in the late 20th century). The Seto Inland Sea is still used, however, by an international cargo transport line and several local transport lines connecting Honshū with Shikoku and Kyūshū. Major cities with heavy industrial activity on

6336-622: The income of the daimyo , which was in the form of koku , giant bales of rice. The Seto Inland Sea was also part of the official Chosendentsushi route, bringing Korean emissaries to the shogunate. After the Meiji Restoration , the coastal cities along the Seto Inland Sea were rapidly industrialized. One of the headquarters of the Japanese Navy was built in the town of Kure . Since the Meiji period, development of land transport has been reducing

6432-519: The large cities along the Mediterranean Sea , for example, discharge all of their sewage into the sea untreated. The same is true for most coastal developing countries, while in parts of the developing world, as much as 70% of wastewater from large cities may re-enter water systems without being treated. Residual nutrients in treated wastewater can also accumulate in downstream source water areas and fuel eutrophication, which leads progressively to

6528-555: The last decade, and new species have emerged in some locations that were not previously known to cause problems. HAB frequency is also thought to be increasing in freshwater systems. Researchers have reported the growth of HABs in Europe, Africa and Australia. Those have included blooms on some of the African Great Lakes , such as Lake Victoria , the second largest freshwater lake in the world. India has been reporting an increase in

6624-408: The main transportation link between Kansai and Kyūshū. Yamaguchi , Hiroshima , Okayama , Hyōgo , Osaka , Wakayama , Kagawa , Ehime , Tokushima , Fukuoka , and Ōita prefectures have coastlines on the Seto Inland Sea; the cities of Hiroshima , Iwakuni , Takamatsu , and Matsuyama are also located on it. The Setouchi region encompasses the sea and surrounding coastal areas. The region

6720-402: The majority of them an essential part of the food web for small fish and other organisms. Harmful algal blooms in freshwater lakes and rivers, or at estuaries , where rivers flow into the ocean, are caused by cyanobacteria, which are commonly referred to as "blue-green algae", but are in fact prokaryotic bacteria, as opposed to algae which are eukaryotes . Some cyanobacteria, including

6816-433: The moderate climate and beautiful landscape, fishing, agriculture, and tourism bring a lot of income to the area as well. Today the Seto Inland Sea serves its coastal areas mainly for two purposes: first, international or domestic cargo transportation, and second, local transportation between coastal areas and islands on the sea. Major ports are Kobe, Okayama, Takamatsu , Tokushima, Matsuyama, and Hiroshima. Historically,

6912-507: The nervous system causing serious injury or death. In the summer of 2015, the state governments closed important shellfish fisheries in Washington , Oregon , and California because of high concentrations of domoic acid in shellfish. In the marine environment, single-celled, microscopic, plant-like organisms naturally occur in the well-lit surface layer of any body of water. These organisms, referred to as phytoplankton or microalgae , form

7008-400: The number of blooms each year. In 1977 Hong Kong reported its first coastal HAB. By 1987 they were getting an average of 35 per year. Additionally, there have been reports of harmful algal blooms throughout popular Canadian lakes such as Beaver Lake and Quamichan Lake. These blooms were responsible for the deaths of a few animals and led to swimming advisories. Global warming and pollution

7104-537: The ongoing degradation of dams, lakes, rivers, and reservoirs - source water areas that are starting to become known as ecological infrastructure, placing increasing pressure on wastewater treatment works and water purification plants. Such pressures, in turn, intensify seasonal HABs. Climate change contributes to warmer waters which makes conditions more favorable for algae growth in more regions and farther north. In general, still, warm, shallow water, combined with high-nutrient conditions in lakes or rivers, increases

7200-582: The open ocean at the surface. The Naruto Strait connects the eastern part of the Seto Inland Sea to the Kii Channel , which in turn connects to the Pacific. The western part of the Seto Inland Sea connects to the Sea of Japan through the Kanmon Straits and to the Pacific through the Bungo Channel . Each part of the Seto Inland Sea has a separate name in Japanese. For example, Iyo-nada ( 伊予灘 ) refers to

7296-796: The railway ( Japan Railways Group ). The high speed Shinkansen does not go to or on Shikoku. This is the first of three intersections of the Seto Inland Sea. Construction started in 1975, but was fully completed in 1999. It connects the Nishiseto- Onomichi Highway in Hiroshima Prefecture with a total of ten bridges and several smaller islands with Imabari in Ehime Prefecture . Approximately 100,000 people live on those islands. The bridges are: Shin Onomichi Bridge, Innoshima Bridge , Ikuchi Bridge, Tatara Bridge , Ōmishima Bridge,

7392-404: The risk of harmful algal blooms. Warming of summer surface temperatures of lakes, which rose by 0.34 °C decade per decade between 1985 and 2009 due to global warming, also will likely increase algal blooming by 20% over the next century. Although the drivers of harmful algal blooms are poorly understood, they do appear to have increased in range expansion and frequency in coastal areas since

7488-484: The seawater and stimulates bloom events. Natural causes, such as river floods or upwelling of nutrients from the sea floor , often following massive storms, provide nutrients and trigger bloom events as well. Increasing coastal developments and aquaculture also contribute to the occurrence of coastal HABs. Effects of HABs can worsen locally due to wind driven Langmuir circulation and their biological effects . HABs from cyanobacteria (blue-green algae) can appear as

7584-476: The strait between Ehime, Yamaguchi, and Ōita prefectures in the western portion of the sea; Aki-nada ( 安芸灘 ) is the open expanse west of the Geiyo Islands , near Hiroshima prefecture; and Suō-nada ( 周防灘 ) refers to the expanse between Yamaguchi prefecture and Suō-Ōshima . These areas are sometimes styled Iyonada, Akinada, and Suonada. There are also many straits located between the major islands, as well as

7680-540: The sunlight used by plants and algae to photosynthesise, or by depleting the dissolved oxygen needed by fish and other aquatic animals, which can lead to fish die-offs. When such oxygen-depleted water covers a large area for an extended period of time, it can become hypoxic or even anoxic; these areas are commonly called dead zones . These dead zones can be the result of numerous different factors ranging from natural phenomenon to deliberate human intervention, and are not just limited to large bodies of fresh water as found in

7776-489: The surface. These species will then transition from the benthic resting stage into the pelagic vegetative state - where they are more active and found near the water body surface. In the pelagic vegetative state, these cells are able to grow and multiply. It is within the pelagic vegetative state that a bloom is able to occur - as the cells rapidly reproduce and take over the upper regions of the body of water. The transition between these two life stages can have multiple effects on

7872-403: The term "harmful algal blooms" in the media and scientific literature is varied. In a broader definition, all "organisms and events are considered to be HABs if they negatively impact human health or socioeconomic interests or are detrimental to aquatic systems". A harmful algal bloom is "a societal concept rather than a scientific definition". A similarly broad definition of HABs was adopted by

7968-669: The town government, and one public high school operated by the Yamaguchi Prefectural Board of Education. Hirao has no passenger railway service. The nearest station is the JR West Sanyo Main Line Yanai Station or Tabuse Station . This article about a location in Yamaguchi Prefecture is a stub . You can help Misplaced Pages by expanding it . Seto Inland Sea The Seto Inland Sea ( 瀬戸内海 , Seto Naikai ) , sometimes shortened to

8064-400: The toxins in the phytoplankton cause filter-feeding shellfish in affected waters to become poisonous for human consumption. As algal blooms grow, they deplete the oxygen in the water and block sunlight from reaching fish and plants. Such blooms can last from a few days to many months. With less light, plants beneath the bloom can die and fish can starve. Furthermore, the dense population of

8160-407: The toxins they produce or from using up oxygen in the water which can lead to fish die-offs. Not all algal blooms produce toxins, however, with some only discoloring water, producing a smelly odor, or adding a bad taste to the water. Unfortunately, it is not possible to tell if a bloom is harmful from just appearances, since sampling and microscopic examination is required. In many cases microscopy

8256-549: The two Ōshima bridges and the three Kurushima Kaikyo bridges. The Kurushima Kaikyō Bridge connects the island of Ōshima to the main island of Shikoku . The Akinada Tobishima Kaido route connects seven of the western Geiyo Islands to mainland Honshu near Kure, Hiroshima . Seto Naikai Pilots Area provides compulsory maritime piloting for vessels over 10,000 tones, it was divided into sections of Bisanseto and sections of Kurushima , connecting Kanmon Channel Piloting Area and Osaka Bay Piloting Area. The coastal area of

8352-403: The water since many pets have died from algal blooms. In at least one case, people began getting sick before warnings were issued. There is no treatment available for animals, including livestock cattle, if they drink from algal blooms where such toxins are present. Pets are advised to be kept away from algal blooms to avoid contact. In some locations visitors have been warned not to even touch

8448-468: The water. Boaters have been told that toxins in the water can be inhaled from the spray from wind or waves. Ocean beaches, lakes and rivers have been closed due to algal blooms. After a dog died in 2015 from swimming in a bloom in California's Russian River , officials likewise posted warnings for parts of the river. Boiling the water at home before drinking does not remove the toxins. In August 2014

8544-456: The western area of Japan as their route to and from Edo , to fulfill their obligations under sankin-kōtai . Many used ships from Osaka. Thanks to transport through the Seto Inland Sea, Osaka became the economic center of Japan. Each han had an office called Ozakayashiki in Osaka. These Ozakayashiki were among Japan's earliest forms of banks, facilitating domestic trade and helping to organize

8640-766: The western end of the Sea is Mimosusogawa Park ( ja:みもすそ川公園 ) in Shimonoseki . It commemorates the final stage of the Genpei war between the feudal Taira clan and Minamoto clan (1180–1185). Some sites along the Seto Inland Sea were featured in eighth-century Japanese literature, both in prose and in verse, including Kojiki , Nihon Shoki , and Man'yōshū . Since some sites were used as places of exile, their feeling and landscape were evoked in waka . In fiction, in The Tale of Genji , Genji fled from Kyoto and resided in Suma (now

8736-800: The widespread genus Microsystis , can produce hazardous cyanotoxins such as microcystins , which are hepatotoxins that harm the liver of mammals. Other types of cyanobacteria can also produce hepatotoxins, as well as neurotoxins, cytotoxins, and endotoxins. Water purification plants may be unable to remove these toxins, leading to increasingly common localised advisories against drinking tap water, as happened in Toledo, Ohio in August ;2014. In August 2021, there were 47 lakes confirmed to have algal blooms in New York State alone. In September 2021, Spokane County's Environmental Programs issued

8832-474: The world each year. In 1987 a new illness emerged: amnesic shellfish poisoning (ASP). People who had eaten mussels from Prince Edward Island were found to have ASP. The illness was caused by domoic acid , produced by a diatom found in the area where the mussels were cultivated. A 2013 study found that toxic paralytic shellfish poisoning in the Philippines during HABs has caused at least 120 deaths over

8928-481: The world is in fact a real increase or is due to increased observation effort and advances in species identification technology. In 2008, the U.S. government prepared a report on the problem, "Harmful Algal Bloom Management and Response: Assessment and Plan". The report recognized the seriousness of the problem: It is widely believed that the frequency and geographic distribution of HABs have been increasing worldwide. All U.S. coastal states have experienced HABs over

9024-467: Was abolished. The main islands Honshū and Shikoku are connected by three series of bridges since the late 1980s. This improves land transportation between the connected islands. These series of bridges, collectively known as the Honshū–Shikoku Bridge Project , are, from east to west, Akashi Kaikyo Bridge , Great Seto Bridge , and Nishiseto Expressway . The easternmost highway was built between 1976 and 1998. It leads from Akashi ( Hyōgo Prefecture ) on

9120-578: Was forecast again for the summer of 2016. In 2004, a bloom in Kisumu Bay, which is the drinking water source for 500,000 people in Kisumu , Kenya , suffered from similar water contamination. In China, water was cut off to residents in 2007 due to an algal bloom in its third largest lake, which forced 2 million people to use bottled water. A smaller water shut-down in China affected 15,000 residents two years later at

9216-504: Was part of the holdings of Chōshū Domain . Following the Meiji restoration , the village of Hirao within Kumage District, Yamaguchi was established with the creation of the modern municipalities system on April 1, 1889. Hirao was elevated to town status on April 1, 1903. On January 1, 1955 Tabuse annexed the villages of Ono, Saga and Sone. Hirao has a mayor-council form of government with

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