The northeastern Chukchi Sea: benthos-environmental interactions

Abstract

Benthic faunal abundance, diversity, and biomass were examined in the northeastern Chukchi Sea to determine factors influencing faunal distribution. Four taxon-abundance-based benthic station groups were identified by cluster analysis and ordination techniques. These groups are explained, using stepwise multiple discriminant analysis, by the gravel-sand-mud and water content of bottom sediments, and the organic carbon/nitrogen (OC/N) ratio. In contrast to previous benthic investigations in the northeastern Bering and southeastern Chukchi Seas, faunal diversity between inshore and offshore regions in our study area were not related to differences in sediment sorting. Instead, regional diversity differences in the northeastern Chukchi Sea were related to greater environmental stresses (e.g. ice gouging, wave-current action, marine-mammal feeding activities) inshore than offshore. The presence of a high benthic biomass north of Icy Cape in the vicinity of Point Franklin and seaward of a hydrographic front is presumably related to an enhanced local depositional flux of particulate organic carbon (POC) in the area. We postulate that POC-rich waters derived from the northern Bering and northwestern Chukchi Seas extend to our study area and the flux of the entrained POC provides a persistent source of carbon to sustain the high benthic biomass. Annual POC enrichment of the coastal region north of Icy Cape is reflected by the great abundance of amphipods and other invertebrates present there and the concentration in summer of walrus Odobenus rosmarus djvergens and gray whales Eschrichtius robustus that feed on these invertebrates. This study demonstrates that there can be high standing stocks of benthos in arctic regions with relatively low annual primary production if local carbon is augmented by POC advected from highly productive areas.

Mega-epibenthic diversity: a polar comparison

“…We believe that high dominance and thereby low α-diversity and high β-diversity are related to environmental stress, and partly, therefore, by the way in which this affects environmental heterogeneity. Feder et al (1994) came to similar conclusions. They also related offshore/inshore dissimilarities in diversity in the northeastern Chukchi Sea to regional differences in environmental stress.…”

Macrozoobenthos of the Pechora Sea (SE Barents Sea): community structure and spatial distribution in relation to environmental conditions

“…Chukchi Sea : Feder et al 1994; Canadian shelf areas: Thomson 1982, Stewart et al 1985. Although the total number of taxa (712) reported here at 87 stations include 505 species, they represent only ~35% of that observed in the whole Barents Sea area (Zenkevich 1963, Sirenko 1998, the Pechora Sea can be regarded as considerably species-rich.…”

“…Kusnetsov 1970, Thomson 1982, Long & Lewis 1987, Grebmeier et al 1989, Feder et al 1994, Dahle et al 1998, Sejr et al 2000. In the Pechora Sea open-sea areas the environmental conditions are typically more stable than in the highly varying coastal areas, which are affected by seasonal variations in ice scouring, freshwater discharge and temperature.…”

The Barents and Chukchi Seas: Comparison of two Arctic shelf ecosystems

“…Some authors (e.g., Feder et al, 1994Feder et al, , 2007Renaud et al, 2007) have suggested that depth may be more important than specific water mass characteristics in generating broad-scale biomass patterns in both seas, perhaps due, in part, to influences on high-biomass epifaunal assemblages. Depth serves as a proxy for multiple covariates including increased decomposition of production with greater water depth, water mass and current changes, stratification, water temperature and salinity, and interactions with topography and water mass movements.…”

“…5, see also Feder et al, 1994;Grebmeier et al, 2006a). In the Chukchi, benthic macrofaunal survey data are predominately from the eastern areas, thus potentially creating a bias in our sampling of the benthos (Feder et al, 1994;Grebmeier, 2012;Grebmeier et al, 2006a).…”