Clipperton Island ( ; ), also known as Clipperton Atoll and previously as Clipperton's Rock, is an uninhabited coral atoll in the eastern Pacific Ocean. The only French territory in the North Pacific, Clipperton is from Paris, France; from Papeete, French Polynesia; and from Acapulco, Guerrero.
Clipperton was documented by French merchant-explorers in 1711 and formally claimed as part of the French protectorate of Tahiti in 1858. Despite this, American guano miners began working the island in the early 1890s. As interest in the island grew, Mexico asserted a claim to the island based upon Spanish records from the 1520s that may have identified the island. Mexico established a small military colony on the island in 1905. During the Mexican Revolution, contact with the mainland became infrequent, most of the colonists died, and lighthouse keeper Victoriano Álvarez instituted a short, brutal reign as "king" of the island. Eleven survivors were rescued in 1917 and Clipperton was abandoned.
The dispute between Mexico and France over Clipperton was taken to binding international arbitration in 1909. Victor Emmanuel III, King of Italy, was chosen as arbitrator and decided in 1931 that the island was French territory. Despite the ruling, Clipperton remained largely uninhabited until 1944 when the U.S. Navy established a weather station on the island to support its war efforts in the Pacific. France protested and, as concerns about Japanese activity in the eastern Pacific waned, the U.S. abandoned the site in late 1945.
Since the end of World War II, Clipperton has primarily been the site for scientific expeditions to study the island's wildlife and marine life, including its significant masked and brown booby colonies. It has also hosted climate scientists and amateur radio DX-peditions. Plans to develop the island for trade and tourism have been considered, but none have been enacted and the island remains mostly uninhabited, with periodic visits from the French Navy.
Geography
The coral island is located at in the East Pacific, southwest of Mexico, west of Nicaragua, west of Costa Rica, and northwest of the Galápagos Islands in Ecuador. The nearest land is Socorro Island, about to the northwest in the Revillagigedo Archipelago. The nearest French-owned island is Hiva Oa in the Marquesas Islands of French Polynesia, which is about 3,300 km (1,781 nmi) southwest of Clipperton.
Despite its proximity to North America, Clipperton is often considered one of the eastern-most points of Oceania because it is part of the French Indo-Pacific, and its marine fauna are similar to those of Hawaii and Kiribati's Line Islands—Clipperton lies on Eastern Tropical Pacific migration paths. The island is the only emerged part of the East Pacific Rise, as well as the only feature in the Clipperton fracture zone that breaks the ocean's surface, and it is one of the few islands in the Pacific that lacks an underwater archipelagic apron.
The atoll is low-lying and largely barren, with some scattered grasses, and a few clumps of coconut palms (Cocos nucifera). The land ring surrounding the lagoon measures in area with an average elevation of , although a small volcanic outcropping, referred to as Clipperton Rock (), rises to on its southeast side. The surrounding reef hosts an abundance of corals and is partly exposed at low tide. In 2001 a geodetic marker was placed to evaluate if the land is rising or sinking.
Clipperton Rock is the remains of the island's now extinct volcano's rim; because it includes this rocky outcropping, Clipperton is not a true atoll and is sometimes referred to as a 'near-atoll'. The surrounding reef in combination with the weather makes landing on the island difficult and anchoring offshore hazardous for larger ships; in the 1940s American ships reported active problems in this regard.
Environment The environment of Clipperton Island has been studied extensively with the first recordings and sample collection being done in the 1800s. Modern research on Clipperton is focused primarily on climate science and migratory wildlife.
The SURPACLIP oceanographic expedition, a joint undertaking by the National Autonomous University of Mexico and the University of New Caledonia Nouméa, made extensive studies of the island in 1997. In 2001, French National Centre for Scientific Research geographer Christian Jost extended the 1997 studies through the French Passion 2001 expedition, which focused on the evolution of Clipperton's ecosystem. In 2003, cinematographer Lance Milbrand stayed on the island for 41 days, recording the adventure for the National Geographic Explorer and plotting a GPS map of Clipperton for the National Geographic Society.
In 2005, a four-month scientific mission organised by Jean-Louis Étienne made a complete inventory of Clipperton's mineral, plant, and animal species; studied algae as deep as below sea level; and examined the effects of pollution. A 2008 expedition from the University of Washington's School of Oceanography collected sediment cores from the lagoon to study climate change over the past millennium.
Lagoon Clipperton is a ring-shaped atoll that completely encloses a stagnant fresh water lagoon and measures in circumference and in area. The island is the only coral island in the eastern Pacific. The lagoon is devoid of fish, and is shallow over large parts except for some deep basins with depths of , including a spot known as ('the bottomless hole') with acidic water at its base. The water is described as being almost fresh at the surface and highly eutrophic. Seaweed beds cover approximately 45% of the lagoon's surface. The rim averages in width, reaching in the west, and narrowing to in the north-east, where sea waves occasionally spill over into the lagoon. Ten islets are present in the lagoon, six of which are covered with vegetation, including the Egg Islands ().
The closure of the lagoon approximately 170 years ago and prevention of seawater from entering the lagoon has formed a meromictic lake. The bottom of the shallow parts of the lake contain eroded coral heads from when the lagoon was last connected with the ocean. During visits in 1897 and 1898 the depth at the middle of the lagoon was recorded as being between two inches and two feet due to the dead coral. The surface of the lagoon has a high concentration of phytoplankton that vary slightly with the seasons. As a result of this the water columns are stratified and do not mix leaving the lagoon with an oxic and brackish upper water layer and a deep sulphuric anoxic saline layer. At a depth of approximately the water shifts with salinity rising and both pH and oxygen quickly decreasing. The deepest levels of the lagoon record waters enriched with hydrogen sulfide which prevent the growth of coral. Before the lagoon was closed off to seawater, coral and clams were able to survive in the area as evident by fossilised specimens.
Studies of the water have found that microbial communities on the water's surface are similar to other water samples from around the world with deeper water samples showing a great diversity of both bacteria and archaea. In 2005, a group of French scientists discovered three dinoflagellate microalgae species in the lagoon: Peridiniopsis cristata, which was abundant; Durinskia baltica, which was known to exist previously in other locations, but was new to Clipperton; and Peridiniopsis cristata var. tubulifera, which is unique to the island. The lagoon also harbours millions of isopods, which are reported to deliver a painful bite.
While some sources have rated the lagoon water as non-potable, testimony from the crew of the tuna clipper M/V Monarch, stranded for 23 days in 1962 after their boat sank, indicates otherwise. Their report reveals that the lagoon water, while "muddy and dirty", was drinkable, despite not tasting very good. Several of the castaways drank it, with no apparent ill effects. Survivors of a Mexican military colony in 1917 (see below) indicated that they were dependent upon rain for their water supply, catching it in old boats. American servicemen on the island during World War II had to use evaporators to desalinate the lagoon's water. Aside from the lagoon and water caught from rain, no freshwater sources are known to exist.
Climate The island has a tropical oceanic climate, with average temperatures of and highs up to . Annual rainfall is , and the humidity level is generally between 85 per cent and 95 per cent with December to March being the drier months. The prevailing winds are the southeast trade winds. The rainy season occurs from May to October, and the region is subject to tropical cyclones from April to September, but such storms often pass to the northeast of Clipperton. In 1997 Clipperton was in the path of the start of Hurricane Felicia, as well as Hurricane Sandra in 2015. In addition, Clipperton has been subjected to multiple tropical storms and depressions, including Tropical Storm Andres in 2003. Surrounding ocean waters are warm, pushed by equatorial and counter-equatorial currents and have seen temperature increases due to global warming.
Flora and fauna
When Snodgrass and Heller visited in 1898, they reported that "no land plant is native to the island". Historical accounts from 1711, 1825, and 1839 show a low grassy or suffrutescent (partially woody) flora. During Marie-Hélène Sachet visit in 1958, the vegetation was found to consist of a sparse cover of spiny grass and low thickets, a creeping plant (Ipomoea spp.), and stands of coconut palm. This low-lying herbaceous flora seems to be a pioneer in nature, and most of it is believed to be composed of recently introduced species. Sachet suspected that Heliotropium curassavicum, and possibly Portulaca oleracea, were native. Coconut palms and pigs introduced in the 1890s by guano miners were still present in the 1940s. The largest coconut grove is Bougainville Wood () on the southwestern end of the island. On the northwest side of the atoll, the most abundant plant species are Cenchrus echinatus, Sida rhombifolia, and Corchorus aestuans. These plants compose a shrub cover up to in height, and are intermixed with Eclipta, Phyllanthus, and Solanum, as well as the taller Brassica juncea. The islets in the lagoon are primarily vegetated with Cyperaceae, Scrophulariaceae, and Ipomoea pes-caprae. A unique feature of Clipperton is that the vegetation is arranged in parallel rows of species, with dense rows of taller species alternating with lower, more open vegetation. This was assumed to be a result of the trench-digging method of phosphate mining used by guano hunters.
The only land animals known to exist are two species of reptiles (the Pacific stump-toed gecko and the copper-tailed skink), bright-orange land crabs known as Clipperton crabs (Johngarthia oceanica, prior to 2019 classified as Johngartia planata), birds, and ship rats. The rats probably arrived when large fishing boats wrecked on the island in 1999 and 2000.