Publication Date:
2019-04-16
Description:
Water samples and suspended matter taken in the Atlantis-II Deep area (Red Sea) during the expedition SO-2 (with RV “Sonne”) in November 1977 were investigated for chemical composition. Only slight changes have been found for most components since 1966. A strong decrease of the Cu content (from 100–500 μg kg−1 according to Brooks et al., 1969, to values below 1 μg kg−1) has, however, become evident.
Comparison between theoretical concentrations in the intermediate brine layers (resulting when using the lower or the upper homothermal layers, respectively, as end members of mixing processes with Red Sea deep water) and the concentrations measured prove that precipitation and resolution processes have considerable influence on the concentrations found in solution. Components strongly involved in such processes are: iron, manganese, copper, oxygen, sulfate, and silica, as could be shown from comparison of theoretical and measured concentration profiles along the water column.
Investigations of the metals suspended in the brine confirm these processes. Compared to 1971/1972, the Cu and Zn values in suspension (preferring the southwestern basin at that time) are clearly reduced — thus being in agreement with the recently lowered hydrothermal activity. Remarks on the hypothetical composition of the unknown hydrothermal brine discharging into the deepest basin are also included.
Type:
Article
,
PeerReviewed
Format:
text
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