The Dead Sea: Deepening of the Mixolimnion Signifies the Overture to Overturn of the Water Column

Abstract-A massive bloom of halobacteria that had developed in the upper water layers of the Dead Sea in summer 1980 together with a bloom of the unicellular green algae Dunaliellu was present for more than 2 years. Simulation experiments performed in ponds in the Dead Sea area showed that the availability of phosphate, the extent of dilution with less saline water, and the availability of a suitable carbon source determine the extent of the development of halobacteria in Dead Sea water.The number of particles resembling bacteria per milliliter of surface water decreased more than fivefold between November and December 1982, while the particulate protein decreased to below detection limits. This sudden decrease was correlated with a change in the physical structure of the water column from stratification to overturn.

supporting

confidence: 72%

The rise and decline of a bloom of halobacteria in the Dead Sea1

Oren¹

1985

“…Extremely halophilic photosynthetic sulfur bacteria have been described (Imhoff and Triiper 1977), but they have never been found in the Dead Sea; the relatively high oxygen concentrations in the upper layers of the Dead Sea and the absence of sulfide from the entire water column during the last few years (Steinhorn et al 1979) would not favor their development.…”

Section: Discussionmentioning

confidence: 99%

Bacteriorhodopsin‐mediated CO₂ photoassimilation in the Dead Sea1

Oren

1983

“…Griesel ( 19 3 5) examined evidence of mixed-layer deepening over a 20-yr period in the Hemmelsdorf See, but ended his observations before overturn. Steinhorn (1985) and others (Steinhorn et al 19 79) documented the successive deepening of the mixed layer of the Dead Sea during the late 1970s and overturn in 1979. Stiller and Chung ( 1!>84) used the Ra activity in Dead Sea surface water and deep water before turnover to estimate the time since the previous holomixis.…”

Section: Acknowledgmentsmentioning

confidence: 91%

Meromixis in hypersaline Mono Lake, California. 3. Biogeochemical response to stratification and overturn

Miller

Jellison

Oremland

et al. 1993

Mono Lake is a terminal, saline lake that became ectogenically meromictic in 1982-l 983 and remained stratified until November 1988. During this period, the monimolimnion remained anoxic and nearly isothermal, while the upper mixolimnion was well oxygenated and exhibited a seasonal thermal regime. Dissolved sulfide and methane increased in the monimolimnion as a result of diffusive flux from the sediments. Winter mixing down to the chemocline distributed sulfide and methane throughout the mixolimnion. Lakewide inventories of dissolved sulfide and methane rcflccted the balance between increased concentrations and decreased monimolimnion volume over time. At overturn, the entire water column was isothermal and anoxic. Dissolved sulfide (380 x 10" mol) was oxidized in 1 week by molecular oxygen. Methane ( 12 x 1 O6 mol) was removed more slow1 y by microbial oxidation and ventilation across the air-water interface.