Experimental evidence of reduced particle resuspension within a seagrass (Posidonia oceanica L.) meadow

Dried leaf fragments of the Mediterranean seagrass Posidonia oceanica were used as tracer particles to test if seagrass leaf canopies reduce particle resuspension. Half Petri dishes containing a known mass of tracer particles were deployed for 24 h, five times during the summer period inside a 15-m deep P. oceanica meadow and on an adjacent sandy bottom devoid of vegetation. The loss of tracer particles was consistently high (>62.9% of initial particle mass) at sand stations, while both high ( > 79.2% of initial particle mass) and low ( < 47.7% of initial particle mass) losses were recorded at P. oceanica stations. The loss of tracer particles was lower (P < 0.01) within the P, oceanica meadow than over barren sand, which supports the hypothesis that seagrass leaf canopies are able to reduce particle resuspension. (C) 2000 Elsevier Science B.V. All rights reserved.