Occasional Whiteness of the Dead Sea

Bloch, R. Howard; Littman, H. Z.; Elazari-Volcani, B.

doi:10.1038/154402a0

Cited by 30 publications

(8 citation statements)

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“…Aragonite crystallized from the upper water body and settled to the bottom, forming the white laminae of the Dead Sea sediments, whereas gypsum crystallized on exposed and submerged surfaces along the shores. The "whitening" of the Dead Sea surface , which has been described by several observers before the overturn (Bloch et al, 1943;Neev and Emery, 1967), is attributed to spontaneous crystallization of aragonite, possibly with some gypsum, from the surface water. The Dead Sea sediments are thus characterized by alternating laminae of detrital material which precipitated following the winter flooding to the lake and laminae consisting mainly of aragonite with some gypsum which precipitated usually during summer.…”

Section: The Chemistry Of the Dead Sea Brinementioning

confidence: 94%

The Dead Sea as a Dying Lake

Gavrieli

Oren

2004

NATO Science Series: IV: Earth and Environmental Sciences

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Section: The Chemistry Of the Dead Sea Brinementioning

confidence: 94%

The Dead Sea as a Dying Lake

Gavrieli

Oren

2004

NATO Science Series: IV: Earth and Environmental Sciences

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“…At the time of Volcani's early studies precipitation of CaCO 3 were occasionally observed, causing whitening of the water [3,38]. No such events have been documented in recent years; however, due to the negative water balance, massive amounts of NaCl now precipitate from the water column to the lake bottom as halite crystals.…”

Section: Physical and Chemical Properties Of The Dead Sea And Their Lmentioning

confidence: 99%

Benjamin Elazari Volcani, 1915–1999

Oren

Ventosa²

1999

Extremophiles

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“…Whiting is a short-lived phenomenon of milky parcels of water or bright in-water features, which has been reported globally in lacustrine, marine and freshwater environments and in semi-enclosed areas [1][2][3][4][5][6][7]. The ephemeral patches in whiting are turbid water with high levels of suspended fine-grained calcium carbonate mineral particles [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Spatiotemporal Mapping and Monitoring of Whiting in the Semi-Enclosed Gulf Using Moderate Resolution Imaging Spectroradiometer (MODIS) Time Series Images and a Generic Ensemble Tree-Based Model

et al. 2019

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Whiting events in seas and lakes are a natural phenomenon caused by suspended calcium carbonate (CaCO3) particles. The Arabian Gulf, which is a semi-enclosed sea, is prone to extensive whiting that covers tens of thousands of square kilometres. Despite the extent and frequency of whiting events in the Gulf, studies documenting the whiting phenomenon are lacking. Therefore, the primary objective of this study was to detect, map and document the spatial and temporal distributions of whiting events in the Gulf using daily images acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra and Aqua satellites from 2002 to 2018. A method integrating a geographic object-based image analysis, the correlation-based feature selection technique (CFS), the adaptive boosting decision tree (AdaBoost DT) and the rule-based classification were used in the study to detect, quantify and assess whiting events in the Gulf from the MODIS data. Firstly, a multiresolution segmentation was optimised using unsupervised quality measures. Secondly, a set of spectral bands and indices were investigated using the CFS to select the most relevant feature(s). Thirdly, a generic AdaBoost DT model and a rule-based classification were adopted to classify the MODIS time series data. Finally, the developed classification model was compared with various tree-based classifiers such as random forest, a single DT and gradient boosted DT. Results showed that both the combination of the mean of the green spectral band and the normalised difference index between the green and blue bands (NDGB), or the combination of the NDGB and the colour index for estimating the concentrations of calcium carbonates (CI) of the image objects, were the most significant features for detecting whiting. Moreover, the generic AdaBoost DT classification model outperformed the other tested tree-based classifiers with an overall accuracy of 97.86% and a kappa coefficient of 0.97. The whiting events during the study period (2002–2018) occurred exclusively during the winter season (November to March) and mostly in February. Geographically, the whiting events covered areas ranging from 12,000 km2 to 60,000 km2 and were mainly located along the southwest coast of the Gulf. The duration of most whiting events was 2 to 6 days, with some events extending as long as 8 to 11 days. The study documented the spatiotemporal distribution of whiting events in the Gulf from 2002 to 2018 and presented an effective tool for detecting and motoring whiting events.

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Occasional Whiteness of the Dead Sea

Cited by 30 publications

References 1 publication

The Dead Sea as a Dying Lake

The Dead Sea as a Dying Lake

Benjamin Elazari Volcani, 1915–1999

Spatiotemporal Mapping and Monitoring of Whiting in the Semi-Enclosed Gulf Using Moderate Resolution Imaging Spectroradiometer (MODIS) Time Series Images and a Generic Ensemble Tree-Based Model

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