Ōike
Karst pond in Minamidaito, Okinawa, Japan
title: "Ōike" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["landforms-of-okinawa-prefecture", "karst", "ponds-of-japan", "wetlands-of-japan"] description: "Karst pond in Minamidaito, Okinawa, Japan" topic_path: "geography/japan" source: "https://en.wikipedia.org/wiki/Ōike" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Karst pond in Minamidaito, Okinawa, Japan ::
::data[format=table title="Infobox body of water"]
| Field | Value |
|---|---|
| name | Ōike |
| native_name | ja |
| image | Minamidaito-148.jpg |
| location | Minamidaitōjima, Okinawa Prefecture, Japan |
| coordinates | |
| catchment | |
| date-built | |
| date-flooded | |
| length | |
| width | |
| area | 0.31 km2 |
| depth | |
| max-depth | 1.3 m |
| volume | |
| shore | 5.50 km |
| elevation | |
| temperature_high | |
| temperature_low | |
| pushpin_map | Japan Ryukyu Islands |
| :: |
| name = Ōike | native_name =ja | other_name = | image = Minamidaito-148.jpg | alt = | caption = | image_bathymetry = | alt_bathymetry = | caption_bathymetry = | location = Minamidaitōjima, Okinawa Prefecture, Japan | group = | coordinates = | type = | etymology = | part_of = | inflow = | rivers = | outflow = | oceans = | catchment = | basin_countries = | agency = | designation = | date-built = | engineer = | date-flooded = | length = | width = | area = 0.31 km2 | depth = | max-depth = 1.3 m | volume = | residence_time = | salinity = | shore = 5.50 km | elevation = | temperature_high = | temperature_low = | frozen = | islands = | islands_category = | sections = | trenches = | benches = | cities = | pushpin_map = Japan Ryukyu Islands | pushpin_label_position = | pushpin_map_alt = | pushpin_map_caption = | website = | reference =
Ōike is a karst pond on Minamidaitōjima, Okinawa Prefecture, Japan. Ōike is the largest pond containing both freshwater and seawater. It covers 0.31 km2, the circumference is 5.50 km, and it is 1.3 m at its deepest point. Fresh water is mixed with seawater beneath. ::figure[src="https://upload.wikimedia.org/wikipedia/commons/b/b6/Minamidaito_island_Oike-pond_aerial_photograph.JPG" caption="Aerial photograph of Ōike taken in 1978, smaller ponds are visible around the Ōike Pond"] ::
Geology
The island is composed of elevated limestone from its atoll. Rainwater has dissolved the limestone leading to a depression in the ground (sinkhole). This has filled with water to become a pond.
Natural history
On the north of the pond extends an area of wetland with large communities of Bruguera gymnorrhiza, a mangrove plant, which was designated as a Natural monument since it is unique in freshwater on March 18, 1975. Other plants include Scirpus tabemaemontani C. C. Gemlin, Panicum repens L. Najas marina and Vallisneria natans.
Common carp and Carassius auratus langsdorfii were introduced in 1910 and tilapia in 1955. Birds include mallard, Pacific reef heron, common moorhen and cattle egret.
Footnotes
References
- Ministry of the Environment, Environment of lakes and ponds in Japan part 2 1995, Nature and Environment Research Center,
- Masaaki Tanaka, Lakes and ponds in Japan 2 2004, University of Nagoya Press,
References
- Environmental Agency''The 4th Reports on Japanese Lakes and Ponds- Chugoku, Shikoku, Kyushu and Okinawa'' 1993
::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::