Niemann, Helge, Richter, Claudio, Jonkers, Henk M. and Badran, Mohammad I. (2004) Red Sea gravity currents cascade near-reef phytoplankton to the twilight zone. Marine Ecology Progress Series, 269 . pp. 91-99. DOI https://doi.org/10.3354/meps269091.

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Abstract

Cross-reef variations of sea water density, currents and phytoplankton pigments were investigated in the northern Gulf of Aqaba, Red Sea. Differential cooling of near- and offshore surface water during cold winter nights results in cross-shore gradients of density (sigma-t) triggering gravity currents which cascade downslope along sandy valleys. Two 4-wk deployments of 3-D acoustic current meters showed that cross-shore currents near the sea bed (35 and 90 m) were 2- to 5-fold higher than long-shore currents, inversely related to surface flow and highly correlated with seasonally detrended diel variations in seawater temperature. Cross-shore flow varied during the course of the night, with offshore pulses of up to 15 cm s(-1) associated with sudden temperature drops of similar to0.15degreesC. Spatial distribution of chl a pigments shows that phytoplankton enriched nearshore waters are entrained in the gravity currents to depths > 300 m. Gravity currents may therefore provide an important and previously overlooked pathway of reef-borne material to the food-impoverished deeper strata of the Red Sea.

Document Type:	Article
Programme Area:	PA Not Applicable
Research affiliation:	ZMT All
Refereed:	Yes
Document Access:	Open access
DOI:	https://doi.org/10.3354/meps269091
ISSN:	0171-8630
Date Deposited:	20 Mar 2020 10:35
Last Modified:	08 Oct 2026 12:47
URI:	https://cris.leibniz-zmt.de/id/eprint/3672

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