cryptodepression

plural cryptodepressions

1. biologyThe portion of a lake which lies below sea level.

   The lake's elevation above sea level is 74.01 meters (242.8 feet) which makes its depth of cryptodepression to be 170 meters (558 feet).

   1975 March, Robert V. Thomann, Dominick M. DeToro, Richard P. Winfield, Donald J. O’Connor, “Section IV: Lake Ontario – Background”, in Mathematical Modeling of Phytoplankton in Lake Ontario: 1. Model Development and Verification (Ecological Research Series; EPA-660/3-75-005), Corvallis, Or.: National Environmental Research Center, Office of Research and Development, U.S. Environmental Protection Agency, →OCLC, page 8

   4 more examples

   When the bottom of the lake lies below mean sea level, it is said to occupy a cryptodepression, the depth of which is the depth below sea level of the deepest point of the basin.

   1957, G[eorge] Evelyn Hutchinson, A Treatise on Limnology, volumes I (Geography, Physics, and Chemistry), New York, N.Y.: John Wiley & Sons, →OCLC, page 165

   The greater volume of the lake [Lake Susupe] occupies a cryptodepression (that portion which lies below sea level). Based upon a surface elevation of +2.5 ft determined on 20 December 1978 by Juan C. Tenorio and Associates' surveyors, the depth of the cryptodepression is -1.4m (4.7 ft) below sea level.

   1979 June, “Appendix A: Problem Identification”, in A Study to Determine the Feasibility of Providing Flood Control Improvements to the Susupe Chalan Kanoa Area, Island of Saipan, Commonwealth of the Northern Mariana Islands: Draft Detailed Report and Environmental Statement, Fort Shafter [Honolulu], Hi.: U.S. Army Engineer District, Honolulu, →OCLC, page A-10

   At present there are three major closed systems (Awash R. – Afar drainage, northern rift lakes, southern rift lakes), numerous crater lakes with seepage-in and -out, and two cryptodepressions with marine inputs.

   1988, R. B. Wood, J. F. Talling, “Chemical and Algal Relationships in a Salinity Series of Ethiopian Inland Waters”, in Hydrobiologia: The International Journal of Aquatic Sciences, volume 158, Dordrecht: Kluwer Academic Publishers, →ISSN, →OCLC, page 29; reprinted in J. M. Melack, editor, Saline Lakes: Proceedings of the Third International Symposium on Inland Saline Lakes, Held at Nairobi, Kenya, August 1985 (Developments in Hydrobiology; 44), Dordrecht: Dr. W. Junk Publishers, 1988, →DOI, →ISBN, abstract, page 29

   The maximum depth of some lakes is below current sea level. Such lakes are called cryptodepressions. Well-known cases of tectonic lakes include Lake Baikal and the Caspian Sea. Some glacial lakes in Norway, Scotland and England are also cryptodepressions.

   [2012, José Galizia Tundisi, Takako Matsumura-Tundisi, “The Origin of Lakes”, in Limnology, Boca Raton, Fla.: CRC Press, →ISBN, section 3.3.10 (Average Slope (α)), page 49