page_title: Mono Lake
section_title: Limnology
hierarchical_section_title: Mono Lake / Limnology
caption_attribution_description: English: Tufa columns, Mono Lake, Eastern Sierra, California
context_page_description: Mono Lake is a saline soda lake in Mono County, California, formed at least 760,000 years ago as a terminal lake in an endorheic basin. The lack of an outlet causes high levels of salts to accumulate in the lake and make its water alkaline.
  The desert lake has an unusually productive ecosystem based on brine shrimp, which thrive in its waters, and provides critical habitat for two million annual migratory birds that feed on the shrimp and alkali flies. Historically, the native Kutzadika'a people ate the alkali flies' pupae, which live in the shallow waters around the edge of the lake.
  When the city of Los Angeles diverted water from the freshwater streams flowing into the lake, it lowered the lake level, which imperiled the migratory birds. The Mono Lake Committee formed in response and won a legal battle that forced Los Angeles to partially replenish the lake level.
context_section_description: The limnology of the lake shows it contains approximately 280 million tons of dissolved salts, with the salinity varying depending upon the amount of water in the lake at any given time. Before 1941, average salinity was approximately 50 grams per liter (g/l) (compared to a value of 31.5 g/l for the world's oceans). In January 1982, when the lake reached its lowest level of 6,372 feet (1,942 m), the salinity had nearly doubled to 99 g/l. In 2002, it was measured at 78 g/l and is expected to stabilize at an average 69 g/l as the lake replenishes over the next 20 years.
  An unintended consequence of ending the water diversions was the onset of a period of "meromixis" in Mono Lake. In the time prior to this, Mono Lake was typically "monomictic"; which means that at least once each year the deeper waters and the shallower waters of the lake mixed thoroughly, thus bringing oxygen and other nutrients to the deep waters. In meromictic lakes, the deeper waters do not undergo this mixing; the deeper layers are more saline than the water near the surface, and are typically nearly devoid of oxygen. As a result, becoming meromictic greatly changes a lake's ecology.
  Mono Lake has experienced meromictic periods in the past; this most recent episode of meromixis, brought on by the end of the water diversions, commenced in 1994 and had ended by 2004.
caption: Mono Lake's "South Tufa" area
exif: {"Image Make": "Canon", "Image Model": "Canon EOS 600D", "Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image DateTime": "2012:08:16 21:29:48", "Image Artist": "", "Image YCbCrPositioning": "Co-sited", "Image Copyright": "", "Image ExifOffset": "348", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "8916", "Thumbnail JPEGInterchangeFormatLength": "13584", "EXIF ExposureTime": "1/250", "EXIF FNumber": "10", "EXIF ExposureProgram": "Program Normal", "EXIF ISOSpeedRatings": "100", "EXIF SensitivityType": "Recommended Exposure Index", "EXIF RecommendedExposureIndex": "100", "EXIF ExifVersion": "0230", "EXIF DateTimeOriginal": "2012:08:16 21:29:48", "EXIF DateTimeDigitized": "2012:08:16 21:29:48", "EXIF ComponentsConfiguration": "YCbCr", "EXIF ShutterSpeedValue": "8", "EXIF ApertureValue": "53/8", "EXIF ExposureBiasValue": "0", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash did not fire", "EXIF FocalLength": "45", "EXIF SubSecTime": "31", "EXIF SubSecTimeOriginal": "31", "EXIF SubSecTimeDigitized": "31", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "5184", "EXIF ExifImageLength": "3456", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "8598", "EXIF FocalPlaneXResolution": "1036800/181", "EXIF FocalPlaneYResolution": "691200/119", "EXIF FocalPlaneResolutionUnit": "2", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF SceneCaptureType": "Standard", "EXIF CameraOwnerName": "", "EXIF BodySerialNumber": "143066110260", "EXIF LensSpecification": "[18, 55, 0/0, 0/0]", "EXIF LensModel": "EF-S18-55mm f/3.5-5.6 IS II", "EXIF LensSerialNumber": "000027f6f2"}