Sedimentological and Biological Changes in the Windsor Mudflat, an Area of Induced Siltation Journal Articles uri icon

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abstract

  • The causeway-induced mudflat at Windsor, Nova Scotia, was studied to determine the effect of rapid sedimentation on the sedimentological and biological characteristics of an intertidal mudflat. Compared to typical Minas Basin mudflats, the Windsor flat has high water content, (50% vs. 30% wet wt, approximately) small grain sizes, and elevated organic carbon content (0.82% vs. 0.24% dry wt). The two principal infaunal species of the Windsor flat, the amphipod Corophium volutator and the clam Macoma balthica, are less abundant than in nearby typical flats (~840 vs. ~13 000/m2 and ~640 vs. ~1500/m2, respectively), while the polychaete Heteromastus filiformis is particularly abundant at Windsor. Macoma balthica at Windsor grow faster and have a shorter lifespan (~6 yr vs. ~13 yr) than at other Minas Basin flats. Compared to other Minas Basin Macoma, the weight of Windsor Macoma increases more slowly with increasing shell size, possibly an adaptation to the more fluid Windsor sediments.These sedimentological and biological characteristics exist at Windsor nearly 10 yr after the start of flat development and show little tendency to approach typical mudflat characteristics. Our results indicate, therefore, that secondary productivity of Macoma and Corophium could be reduced by about two-thirds for at least a decade in existing Minas Basin mudflats that are covered by Windsor-type sediments as a result of the construction of a tidal power dam.Key words: Bay of Fundy, tidal power, sedimentation, water content, organic carbon, infauna, Corophium volutator, Macoma balthica, growth, mortality

publication date

  • September 1, 1980