Recent mollusc distribution patterns and palaeobathymetry, southeastern Beaufort Sea

Abstract

Molluscs were obtained from 515 of the 657 grab samples collected 1970-1972 inclusive from southeastern Beaufort Sea, from 29 of the 46 cores taken in the area, and from raised marine deposits at Kay Point and on Herschel Island, Yukon Territory. One hundred and one species have been identified. Water depth was apparently the major factor controlling species distribution. Holocene sea levels, determined by comparing core faunas with the established depth ranges for living specimens, are considered to be reasonably accurate for near-shore sites, but yield excessively shallow water depth figures for deep stations (outer shelf and slope). The anomalous results are probably related to offshore transport of shallow water species.On a recolte des mollusques dans 515 des 657 echantillons preleves au fond de la partie sud-est de la mer de Beaufort de 1970 a 1972, dans 29 des 46 carottes prises dans cette region et dans les dep8ts marins emerges a Kay Point et sur I'ile de Herschel au Yukon. On a identifie cent une especes. La profondeur de I'eau a apparemment ete le facteur principal qui a contr8le la distribution des especes. Les niveaux marins durant I'Holocene, determines par comparaison de la faune dans les carottes avec I'habitat connu des especes vivantes, semblent i'tre raisonnablement precis pour les sites a proximite du rivage mais indiquent des valeurs de profondeur d'eau trop faibles pour les sites plus profonds (rebord de la plateforme et pente continentale). Les anomalies dans les resultats sont probablement attribuables au transport vers le large d'especes evoluant en eau peu profonde.

Distributional ecology of shallow south-western Beaufort Sea (Arctic Ocean) bivalve Mollusca

“…Boreacola vadosa, the most abundant species, was collected only inshore at depths of 5, 10, and 15 m; 98 % of the individuals were recorded from 1 station (PPB05). Cyrtodaria kurrfana was found exclusively at 5 m. This limited distribution of C. kurriana concurs Classified from field notes with previous reports by Wagner (1977) and Bernard (1979). Sixty-four % of the stations contained fewer than 200 bivalve individuals mY2.…”

“…Wacasey (1977) sampled 12 species in the 5 to 25 m zone in the eastern Beaufort Sea, while a study similar to ours in the nearshore western Beaufort (4 to 23 m) yielded 9 living bivalve species (Hiilsemann, 1962). Higher estimates of the species richness were reported by Wagner (1977) who found 27 living bivalve species from 6 to 35 m in the eastern Beaufort. The most comprehensive report of Beaufort bivalves (Bernard, 1979) reported 20 species at depths of 25 m or less.…”

“…In a study that involved 76 species of living bivalves and gastropods from a broad depth range (3 to 539 m) in the southeastern Beaufort Sea, Wagner (1977) concluded that water depth was the major controlling factor. Specific environmental features that were correlated with depth could not be identified with the techniques used in that study.…”

“…George MacGinitie (1955) and Nettie MacGinitie (1959) published on the molluscs in the Chukchi Sea-Beaufort Sea boundary region in the vicinity of Point Barrow, Alaska. Several reports were later published in connection with assessment of the offshore environment prior to oil development (Hiilsemann, 1962;Wacasey, 1975;Carey and Ruff, 1977;Wagner, 1977). The most complete description of the bivalve fauna of the southwest Beaufort Sea was published by Bernard (1979).…”

Forty Years of Northern Natural Science

“…However, the best studied groups are the Crustacea (Dunbar, 1954;Fontaine, 1955;Squires, 1957Squires, , 1962Squires, , 1967Squires, , 1968Johnson, 1963;Vidal, 1971;Corey, 1981) and the Mollusca (Wagner, 1977;Bernard, 1979;Lubinsky, 1980). Only in these latter two taxa do we have sufficient information on distribution to analyze the faunal composition and zoogeography.…”