Clear Lake (Palau)

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Clear Lake
Clearwater Lake
Palau location map.svg
Red pog.svg
Clear Lake
Location Eil Malk, Rock Islands, Palau
Coordinates 7°09′09″N134°21′34″E / 7.15250°N 134.35944°E / 7.15250; 134.35944 Coordinates: 7°09′09″N134°21′34″E / 7.15250°N 134.35944°E / 7.15250; 134.35944
Lake type Meromictic
Basin  countriesPalau
Max. length330 m (1,100 ft)
Surface area 3.9  ha (10 acres)
Max. depth30 m (100 ft)
Frozennever
Islands none
Settlementsnone

Clear Lake (also Clearwater Lake) is a marine lake located on Eil Malk island in Palau. Eil Malk (also Mecherchar) is part of the Rock Islands, a group of small, rocky, mostly uninhabited islands in Palau's Southern Lagoon, between Koror and Peleliu. There are about 70 other marine lakes located throughout the Rock Islands. Clear Lake is notable for endemic subspecies of golden jellyfish and is one of five marine lakes in Palau used for several scientific researches in evolutionary biology, the other lakes being Jellyfish Lake, Goby Lake, Uet era Ngermeuangel, Uet era Ongael.

Contents

Golden jellyfish

Clear Lake is one of the oldest of meromictic marine lakes in Palau and is circa 15,000 - 12,000 years old. It is connected to the ocean through fissures and tunnels in the limestone of ancient Miocene reef. However the lake is sufficiently isolated and the conditions are different enough that the diversity of species in the lake is greatly reduced from the nearby lagoon. The golden jellyfish Mastigias cf. papua salii [1] and possibly other species in the lake have evolved to be substantially different from their close relatives living in the nearby lagoons.

Lake stratification

Clear Lake is stratified into two layers, an oxygenated upper layer (mixolimnion) and a lower anoxic layer (monimolimnion). The oxygen concentration in the lake declines from about 6 mg/L at the surface to zero at 16 meters (at the chemocline). [2] Stratification is persistent and seasonal mixing does not occur. The lake is one of about 200 saline meromictic lakes that have been identified in the world. However most of these lakes are of freshwater origin. Permanently stratified marine lakes are unusual, but on Eil Malk and on other nearby islands there are eleven other permanently stratified marine lakes, [3] the most renowned one is Jellyfish Lake.

Related Research Articles

<span class="mw-page-title-main">Geography of Palau</span>

The Republic of Palau consists of eight principal islands and more than 250 smaller ones lying roughly 500 miles southeast of the Philippines, in Oceania. The islands of Palau constitute the westernmost part of the Caroline Islands chain. The country includes the World War II battleground of Peleliu and world-famous rock islands. The total land area is 459 km2 (177 sq mi). It has the 42nd largest Exclusive Economic Zone of 603,978 km2 (233,197 sq mi).

<span class="mw-page-title-main">Koror</span> State in Palau

Koror is the state comprising the main commercial centre of the Republic of Palau. It consists of several islands, the most prominent being Koror Island. It is Palau’s most populous state.

<span class="mw-page-title-main">Rock Islands</span> Collection of reef islands in Palau

The Rock Islands of Palau, also called Chelbacheb, are a collection of several hundred small limestone or coral uprises in the Southern Lagoon of Palau between Koror and Peleliu, now an incorporated part of Koror State. There are between 250 and 300 islands in the group according to different sources, with an aggregate area of 42 square kilometers (16 sq mi) and a maximum height of 207 meters (679 ft). The islands were declared a UNESCO World Heritage Site in 2012.

The purple sulfur bacteria (PSB) are part of a group of Pseudomonadota capable of photosynthesis, collectively referred to as purple bacteria. They are anaerobic or microaerophilic, and are often found in stratified water environments including hot springs, stagnant water bodies, as well as microbial mats in intertidal zones. Unlike plants, algae, and cyanobacteria, purple sulfur bacteria do not use water as their reducing agent, and therefore do not produce oxygen. Instead, they can use sulfur in the form of sulfide, or thiosulfate (as well, some species can use H2, Fe2+, or NO2) as the electron donor in their photosynthetic pathways. The sulfur is oxidized to produce granules of elemental sulfur. This, in turn, may be oxidized to form sulfuric acid.

<span class="mw-page-title-main">Ramsar site</span> Wetland site as designated by the Ramsar Convention

A Ramsar site is a wetland site designated to be of international importance under the Ramsar Convention, also known as "The Convention on Wetlands", an intergovernmental environmental treaty established on 2nd February 1971 in Ramsar, Iran by UNESCO, which came into force from 21st December,1975. It provides for national action and international cooperation regarding the conservation of wetlands, and wise sustainable use of their resources. Ramsar identifies wetlands of international importance, especially those providing waterfowl habitat.

<span class="mw-page-title-main">Meromictic lake</span> Permanently stratified lake with layers of water that do not intermix

A meromictic lake is a lake which has layers of water that do not intermix. In ordinary, holomictic lakes, at least once each year, there is a physical mixing of the surface and the deep waters.

<span class="mw-page-title-main">Aquarium of the Pacific</span> Public aquarium in California, U.S.

The Aquarium of the Pacific is a public aquarium on a 5-acre (20,000 m2) site on Rainbow Harbor in Long Beach, California, United States. It is situated across the water from the Long Beach Convention Center, Shoreline Village, and the Queen Mary Hotel and Attraction.

<span class="mw-page-title-main">Hatohobei</span> State in Palau

Tobi, or Hatohobei (Tobian), is the southernmost of Palau's sixteen states, consisting of Tobi Island and Helen Reef. The total land area is about 0.88 km². The population was 25 in 2015. Tobian, English, and Sonsorolese are the official languages of Hatohobei State.

<span class="mw-page-title-main">Jellyfish Lake</span> Marine lake in Palau

Jellyfish Lake is a marine lake located on Eil Malk island in Palau. Eil Malk is part of the Rock Islands, a group of small, rocky, mostly uninhabited islands in Palau's Southern Lagoon, between Koror and Peleliu. There are about 70 other marine lakes located throughout the Rock Islands. Millions of golden jellyfish migrate horizontally across the lake daily.

Salvatnet is a lake in the municipalities of Namsos and Nærøysund in Trøndelag county, Norway. With its deepest depth of 464 metres (1,522 ft), it is Norway's and Europe's second-deepest lake, after Hornindalsvatnet. Alternate sources give the depth as either 464 metres (1,522 ft) or 482 metres (1,581 ft) at the deepest point. The lake sits very close to the ocean, about 9 metres (30 ft) above sea level at the surface and reaches to a depth of 455 metres (1,493 ft) below sea level. It is a very large lake with an area of 44.77 square kilometres (17.29 sq mi), a volume of 6.87 cubic kilometres (1.65 cu mi), and a shoreline that is 105.61 kilometres (65.62 mi) around.

Kakaban island is part of the Derawan Islands, East Kalimantan, Indonesia.

<span class="mw-page-title-main">Spotted jelly</span> Species of jellyfish

The spotted jelly, lagoon jelly, golden medusa, or Papuan jellyfish, is a species of jellyfish from the Indo-Pacific oceans. Like corals, sea anemones, and other sea jellies, it belongs to the phylum Cnidaria. Mastigias papua is one of the numerous marine animals living in symbiosis with zooxanthellae, a photosynthetic alga.

<i>Mastigias</i> Genus of jellyfishes

Mastigias is a genus of true jellyfish in the family Mastigiidae. It contains seven described species. Members of this genus are found widely in coastal regions of the Indo-Pacific, including saline lakes of Palau, but there are also records from the West Atlantic at Florida and Puerto Rico. The West Atlantic records are most likely the result of accidental introductions by humans.

<span class="mw-page-title-main">Eil Malk</span>

Eil Malk or Mecherchar is the main island of the Mecherchar Islands, an island group of Palau in the Pacific Ocean. In a more narrow sense, just the southeastern peninsula of Mecherchar is called Eil Malk.

Goby Lake is a marine lake located on Koror island in Palau. There are about 70 other marine lakes located throughout the Rock Islands and Koror. Goby Lake is notable for endemic subspecies of golden jellyfish and is one of five marine lakes in Palau used for several scientific researches in evolutionary biology the other lakes being Jellyfish Lake, Clear Lake (Palau), Uet era Ngermeuangel, Uet era Ongael.

Uet era Ngermeuangel is a marine lake located on Koror island in Palau. There are about 70 other marine lakes located throughout the Rock Islands and Koror. Uet era Ngermeuangel is notable for endemic subspecies of golden jellyfish and is one of five marine lakes in Palau used for several scientific researches in evolutionary biology the other lakes being Jellyfish Lake, Clear Lake (Palau), Goby Lake, Uet era Ongael.

Uet era Ongael is a marine lake located on Ongael Island, Koror, in Palau. There are about 70 other marine lakes located throughout the Rock Islands and Koror. Uet era Ongael is notable for endemic subspecies of golden jellyfish and is one of five marine lakes in Palau used for several scientific researches in evolutionary biology, the other lakes being Jellyfish Lake, Clear Lake, Uet era Ngermeuangel and Goby Lake.

<span class="mw-page-title-main">Ulong Island</span> Major island and channel of western Palau

Ulong is a major island and channel of western Palau. It is sometimes called Aulong and originally written Oroolong in English. Ulong is regarded by many as one of the best drift dives in the world.

Ongael Island is an island in Koror State, Palau. It is the location of the famous Ongael Lake.

<span class="mw-page-title-main">Golden jellyfish</span> Subspecies of jellyfish

The golden jellyfish is a subspecies of spotted jellyfish that inhabits Jellyfish Lake on Eil Malk island in Palau in the western Pacific Ocean. Like the nominate subspecies, it derives part of its nutrition from symbiotic algae (Zooxanthellae) that live in their tissues and part of their nutrition from captured zooplankton.

References

  1. Dawson M, Michael. "Five new subspecies of Mastigias (Scyphozoa: Rhizostomeae: Mastiigidae) from marine lakes, Palau, Micronesia" . Retrieved 2010-02-11.
  2. "Coral Reef Research Foundation, Clear Lake" . Retrieved 2010-02-11.
  3. Stratified marine lakes of Palau (Western Caroline Islands) Physical Geography 19: 175-220, William Hamner, Peggy Hamner