CGRG Bibliography of Canadian Geomorphology
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Author : Dale, J. E.
Date : 1992
Title : The relationship between the physical environment and benthic faunal communities in Pangnirtung Fiord, Baffin Island, N.W.T.
Publication : Ph.D. thesis, Department of Geography, Queen's University. Kingston Ontario.
Issue :
Page(s) : 425 pp
Abstract
The subtidal environment of Pangnirtung Fiord reveals a complex relationship between cold water marine processes, glaciofluvially-dominated sedimentary environments and arctic benthic communities. Grain size increases downfiord as sediment input from the Weasal River decreases and the influence from ice rafting deposition increases. Faunal communities reflect the substrate conditions. Pangnirtung Fiord is divided into a number of zones, including, soupground, softground, firmground and hardground substrates with associated communities. The diversity of species increases downfiord. Large numbers of motile infaunal opportunists such as Nephtys neotena, Capitella capitata, Axinopsida orbiculata and Portlandia arctica, inhabit the turbid, unstable delta and soupground substrates at the head of the fiord in Overlord basin. The number of sedentary species, epifauna and delicate filter-feeders increase as softgrounds develop by compaction and dewatering in Kunguk and Aulatsivik basins. The greatest diversities and densities of epifauna occur on firmground substrates at the sill at the mouth of the fiord. Hardground communities develop on exposed bedrock surfaces along fiord sidewalls and sill sites and are characterized by epifaunal taxa including Hemithiris psittacea, Tonicella marmorea and Lophyrochiton albus. Faunal islands are special cases of hardground communities which occur in microcosm on isolated ice-rafted cobbles throughout the fiord bottom. Cluster analyses and abundance data reveal greater similarities among sites on the same transect than among sites at similar depths on other transects. The spatial continuity of the faunal communities reveals more stable environments at deep sites below 60 m than shallower sites. Changes in the composition of the benthic communities in the deep-water sites reflect changes in the substrate texture downfiord. Distinct communities inhabit delta sites and shallow sites above 20 m water depth. Mid-depth sites between 20 and 60 m have highly variable communities, but exhibit some similarity with the deeper sites. The 270 invertebrates and 18 macrophytes identified in the fiord reflect both High Arctic and Atlantic/boreal influences. The study includes a number of range extensions, several new records, and a collection of previously undescribed species for arctic Canada.
Bibliography of Canadian Geomorphology