The role of burrows of the SW Atlantic intertidal crab Chasmagnathus granulata in trapping debris

The burrowing crab Chasmagnathus granulata is the most abundant macroinvert ebrate on intertidal mudflats and salt marshes of the South Western Atlanti c. This species excavates and maintains large semi permanent open burrows w ith a mouth opening that may reach 20 cm in diameter and a volume of up to 21. Areas populated by crabs retain a significantly larger amount of debris (mainly plastics) on the surface and have larger amounts of buried debris in the sediment than areas without crabs. Field experiments showed that due to their hydrodynamic characteristics, burrows in the mudflats work as pas sive traps for debris enhancing their retention. Given the extensive intert idal area inhabited by this species in SW Atlantic estuaries, crab bed area s should be considered as large areas that retain debris burying it in the soft bottom environment. (C) 2000 Elsevier Science Ltd. All rights reserved .