CGRG Bibliography of Canadian Geomorphology
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Author : Aitken, A.E.; Risk, M.J.; and Howard, J.D.
Date : 1985
Title : Animal-sediment relationships on an arctic tidal flat : Pangnirtung, Baffin Island, NWT
Publication : 14th Arctic Workshop : Arctic land-sea interaction, 6-8 November, 1985, Bedford Institute of Oceanography, Dartmouth, Nova Scotia
Issue :
Page(s) : 177.
Abstract
The intertidal flats at Pangnirtung are among the best-developed such flats in the Arctic. An inner gravel and boulder beach grades out into sand flats, then muddy sands and sandy muds, then finally an outer boulder barricade. Benthic organisms are abundant throughout the flats. The inner, sandy areas are dominated by the large infaunal lugworm, Arenicola, and the muddier areas by the bivalve Macoma balthica (which may reach population densities of several thousand/m). Another bivalve, Hiatella arctica, is abundant in the outer, rocky areas, and the softshell clam (Mya truncata) may be found, although densities are very low due to human consumption. Benthic polychaetes are common to abundant. The major species are abundant throughout the temperate and boreal waters of the northern hemisphere. Several of the benthic organisms, especially Arenicola, Mya, and Macoma, make characteristic traces in the sediment. A Pleistocene outcrop of sandy sedimentscontained enough characteristic traces to allow us to determine that the sediments had been laid down in an intertidal environment. Experiments on the modern flat using tracers layers and box cores showed that, in summer, the biogenic rate of sediment overturning was very high, faster than some temperate areas. Such Arctic sediments, in outcrop, may differ only subtly from their equivalents in other latitudes. We suggest that these sediments, relative to temperate tidal flat sediments, exhibit more evidence of ice effects and fewer channels. Biologically, Macoma crawling traces are much more common, and evidence of predation less pronounced.
Bibliography of Canadian Geomorphology