Mass transport from pollution sources to remote coral reefs in Eilat (Gulfof Aqaba, Red Sea)

Over the last decades, damage to coral reefs from pollution and over-exploi tation has accelerated alarmingly. The coral reefs of Eilat are currently u ndergoing such severe deterioration, and it has been suggested that polluti on may be responsible. The Eilat pollution sources are located 5-8 km north of the coral reefs, and it is hypothesised that the pollutants reach the r eef sites by current-derived mass transport. This study aimed to test this hypothesis by determining possible occurrence of mass transport from the po llution sites to the reefs, and to determine the pathways and modes of tran sported pollutants. We also wished to test the applicability of the 'fluore scently-labelled tracer' method, as a reliable tool for assessing mass tran sport in coastal marine environments. The results reveal that particulate m atter from pollution sites reaches the remote coral reefs of Eilat, both as bedload and suspension-load particles. Estimates suggest that the minimum velocity of fine particles (5-10 mu m), as suspension load, is 0.4km per da y; while the coarse particle velocity (100-200 mu m), as bedload, is an ord er of magnitude lower, i,e, 0.04 km per day. The results show that fluoresc ently-labelled tracers are a reliable and highly sensitive tool for assessi ng mass transport in marine environments. (C) 1999 Elsevier Science Ltd. Al l rights reserved.