Vadas, R.L., Beal, B.F.

1987. Green algal ropes, a novel estuarine phenomenon in the Gulf of Maine. Estuaries 10(2), 171-176.

During late summer and early autumn of both 1984 and 1985 the authors observed and photographed the development of a green algal bloom on intertidal mudflats in eastern Maine, USA. The bloom culminated in the formation of thick (8-10 cm) mats and long (> 50 m) serpentine rope-like structures. The algal mat was polytypic but composed primarily of Enteromorpha intestinalis L. The authors describe the probable sequence of events which led to the formation of algal ropes. The processes involved appear to parallel the development of ball-like masses in other algae. Algal ropes developed after mat formation, as prevailing winds and tidal currents rolled individual and entwined strands across the mudflat. The great mass of algae eventually became embedded into the sediment surface producing anoxic conditions in the substrate up to several cm deep. The ecological significance and possible negative effects of this altered environment on a commercially important bivalve species are discussed.


A clam flat in upper Whiting Bay (eastern Maine) in May 1985.  Wooden stakes mark 1/4-m2 plots.

The same intertidal flat in July 1985.


The same intertidal flat near the wooden stakes on 6 September 1985.

Wild juveniles of the soft-shell clam, Mya arenaria, entrapped in the green algae in Sept. 1985.

Green algal ropes form in late August and early September 1985.

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