Sediments and Biota of the Marine Coastal Zone of Igloolik Island, Nunavut

Abstract

Few studies in arctic Canada have combined research on both the physical marine environment and benthic invertebrates. This is the first detailed study of the oceanographic conditions and distribution of sediments and biota in the intertidal and subtidal zones of Igloolik Island, Nunavut. Oceanographic measurements (temperature, salinity, dissolved oxygen, turbidity), and sediment and biological sampling were undertaken over two summers (1999, 2002). Intertidal zones are underlain by bedrock with a thin veneer of gravel with a very poorly sorted fine matrix and devoid of benthic invertebrates, due to harsh environmental conditions. Ninety-six benthic invertebrates species were identified in the subtidal zone of Turton Bay, a shallow embayment of Igloolik Island that opens to the south into Hooper Inlet. Oceanographic conditions were similar throughout Turton Bay. The shallow depth of Turton Bay (<25 m) and open fetch to the south means that the bay water is well mixed throughout during the ice-free period. Variations in species, abundances and densities result from local conditions and substrate characteristics. Subtidal areas with unconsolidated substrates have abundant and diversified benthic fauna, whereas those with consolidated substrates have more limited species dominated by epifauna. The greatest abundances and densities occur at the deepest sites with the finest sediments and deposit-feeding species. The shallow subtidal zone (<5 m) is characterized by a thin sandy surface veneer overlying bedrock. It is an extension of the intertidal zone and is much affected by ice action during break-up with reduced numbers of marine fauna. High densities of opportunistic and pollution tolerant species along transects in Turton Bay are explained by the outflow and seepage from the sewage lagoon and dumpsites proximal to these transects.Sédiments et invertébrés de la zone marine côtière de l’île d’Igloolik, Nunavut. Peu d’études menées dans l’arctique canadien combinent les données sur l’environnement physique marin et les invertébrés. Ceci est la première étude détaillée portant sur les conditions océanographiques et la distribution des sédiments et des invertébrés dans les zones intertidales et subtidales de l’île d’Igloolik, Nunavut. Les mesures océanographiques (température, salinité, oxygène dissous, turbidité) et l’échantillonnage des sédiments et des invertébrés ont été menées durant les étés de 1999 et 2002. Les zones intertidales reposent sur de la roche en place avec un mince placage de graviers faiblement triés, exempts d’invertébrés à cause des conditions environnementales rigoureuses. Quatre-vingt-seize espèces d’invertébrés marins ont été identifiées dans la zone sub-tidale de Turton Bay, une baie peu profonde qui se déverse au sud dans Hooper Inlet. La faible profondeur de la baie (<25 m) et son ouverture vers le sud signifie que l’eau est bien mélangée sur toute sa profondeur, pendant la période sans glace. Les variations d’espèces, d’abondance et de densité sont le résultat des conditions locales et de...

Benthic Marine Fauna and Flora of Two Nearshore Coastal Locations in the Western and Central Canadian Arctic

“…Among polychaetes and molluscs, deposit feeders had the greatest species richness for Sachs Harbour and Gjoa Haven, and polychaetes had the greatest species diversity of all higher taxa in both study areas. Similar observations have been made in other Arctic benthic nearshore fauna studies (Lalli et al, 1973;Wacasey et al, 1979;Heath and Thomas, 1984;Thomson et al, 1986;Atkinson and Wacasey, 1989;Leontowich, 2003;Dale and Leontowich, 2006). Despite the high number of samples collected in each location, the total species richness was still not captured, as indicated by the species-accumulation curves, which did not stabilize towards asymptotic values.…”

“…To our knowledge, only two other Arctic benthic studies have reported a nephtyid polychaete as a dominant species. Conlan et al (2008) found Micronephtys minuta to be a characteristic species in the inshore fast ice and flaw lead regions of the Beaufort Shelf, while Dale and Leontowich (2006) found Nephtys neotena to be a prevalent species highly abundant in the subtidal zone of Turton Bay, Igloolik Island, northwest of Foxe Basin. In Sachs Harbour, Thyasira sp.…”

“…Detailed studies of nearshore benthic marine macrofauna and flora for the Canadian Arctic are relatively scarce, except for studies by Ellis (1960), Ellis and Wilce (1961), Lee (1973), Thomson (1982), Reimnitz et al (1992), and Dale and Leontowich (2006) and some technical reports (Wacasey et al, 1979;Heath and Thomas, 1984;Thomson et al, 1986;Atkinson and Wacasey, 1989;Siferd, 2001). Most benthic studies in the Canadian Arctic have concentrated on the benthic macrofauna inhabiting northern fiords (Curtis, 1972;Hunter and Leach, 1983;Dale, 1985;Aitken et al, 1988;Dale et al, 1989;Syvitski et al, 1989;Aitken and Fournier, 1993;Aitken and Gilbert, 1996) and along the Arctic continental shelf (Curtis, 1975;Stewart et al, 1985;Cusson et al, 2007;Conlan et al, 2008).…”