Year‐to‐year variations in Bering Sea ice cover and some consequences for fish distributions

Wyllie‐Echeverria, Tina; Wooster, Warren S.

doi:10.1046/j.1365-2419.1998.00058.x

Cited by 201 publications

(106 citation statements)

References 19 publications

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“…The entire shelf can be divided into northern and southern regions at approximately 60 • N based on the relative influence of sea ice on bottom water temperatures (e.g. Ohtani and Azumaya, 1995;Wyllie-Escheveria, 1995;Wyllie-Escheveria and Wooster, 1998;Coachman, 1986). Three along-shelf domains also exist, differentiated by frontal features imparted by strong horizontal property gradients during summer (e.g., Coachman, 1986;Kinder and Coachman, 1978;Kachel et al, 2002).…”

Section: Geographic Domains and Frontal Systemsmentioning

confidence: 99%

“…Increases in freshwater content caused by melting modify the water column density gradients, contributing to the maintenance of the summer stratification necessary for production (see Optimum Stability estimates by Coyle et al, 2008). Because sea-ice retreat begins in the south (Pease, 1980;Neibauer et al, 1990), ice persists longer over the northern shelf and northern bottom water temperatures in summer and fall are lower, leading to the division of the cross-shelf domains at ∼60 • N. Sea-ice persistence also plays a role in the formation of a cold water mass (<2 • C; Maeda, 1977;Khen, 1998) isolated by thermal stratification in the Middle Domain Wyllie-Escheveria, 1995;Wyllie-Escheveria and Wooster, 1998).…”

Section: Hydrographic Structurementioning

confidence: 99%

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Seasonal distribution of dissolved inorganic carbon and net community production on the Bering Sea shelf

et al. 2010

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Abstract. In order to assess the current state of net community production (NCP) in the southeastern Bering Sea, we measured the spatio-temporal distribution and controls on dissolved inorganic carbon (DIC) concentrations in spring and summer of 2008 across six shelf domains defined by differing biogeochemical characteristics. DIC concentrations were tightly coupled to salinity in spring and ranged from ∼1900 µmoles kg −1 over the inner shelf to ∼2400 µmoles kg −1 in the deeper waters of the Bering Sea. In summer, DIC concentrations were lower due to dilution from sea ice melt, terrestrial inputs, and primary production. Concentrations were found to be as low ∼1800 µmoles kg −1 over the inner shelf. We found that DIC concentrations were drawn down 30-150 µmoles kg −1 in the upper 30 m of the water column due to primary production and calcium carbonate formation between the spring and summer occupations. Using the seasonal drawdown of DIC, estimated rates of NCP on the inner, middle, and outer shelf averaged 28 ± 9 mmoles C m −2 d −1 . However, higher rates of NCP (40-47 mmoles C m −2 d −1 ) were observed in the "Green Belt" where the greatest confluence of nutrient-rich basin water and iron-rich shelf water occurs. We estimated that in 2008, total NCP across the shelf was on the order of ∼96 Tg C yr −1 . Due to the paucity of consistent, comparable productivity data, it is impossible at this time to quantify whether the system is becoming more or less productive. However, as changing climate continues to modify the character of the Bering Sea, we have shown that NCP can be an important indicator of how the ecosystem is functioning.

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Section: Geographic Domains and Frontal Systemsmentioning

confidence: 99%

Section: Hydrographic Structurementioning

confidence: 99%

Seasonal distribution of dissolved inorganic carbon and net community production on the Bering Sea shelf

et al. 2010

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“…Climate shifts may also have affected other clam predators in the Bering Sea, including walruses, seals, fish, crabs, and snails (Wyllie-Echeverria & Wooster 1998, Zheng & Kruse 2000, Conners et al 2002. For these other benthic feeders, an approach such as ours might be useful in evaluating effects of long-term changes in numbers, species, and size structure of prey (Edwards & Huebner 1977, Franz 1977, Hanson et al 1989, Eggleston et al 1992, Nakaoka 1996.…”

Section: Impacts Of the Clam Species Shift On Eider Foragingmentioning

confidence: 99%

Effects of clam species dominance on nutrient and energy acquisition by spectacled eiders in the Bering Sea

Richman¹,

Lovvorn²

2003

Mar. Ecol. Prog. Ser.

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The spectacled eider Somateria fischeri, a 'threatened' species, winters in pack ice of the Bering Sea. In dives of 40 to 70 m for benthic invertebrates, the high energy costs of foraging are offset by high benthic biomass. However, there is evidence that the dominant clam prey has changed from Macoma calcarea to Nuculana radiata, perhaps adversely affecting the foraging energetics of the eiders. We studied effects of differences in nutrient and energy content, crushing resistance of shells, digestibility, gut retention time, areal density, shell length, and depth in the sediments on the relative foraging value of M. calcarea versus N. radiata. To avoid using a 'threatened' species for experiments, we used common eiders Somateria mollissima for digestion studies and white-winged scoters Melanitta fusca (the same size as spectacled eiders) for foraging studies. For the prey size range comprising 93% of the eiders' diet (18 to 30 mm), M. calcarea including shells was lower in ash, and higher in nitrogen, lipid, and energy, than N. radiata. Digestibility was 76% for M. calcarea versus 67% for N. radiata, but gut retention time did not differ. In a tensometer, crushing resistance was much higher for N. radiata than M. calcarea for shells 18 to 24 mm long, but did not differ for 24 to 30 mm because shells of N. radiata were often severely abraded. For scoters foraging on freshly thawed Macoma balthica buried in sand in an aquarium 1.8 m deep, intake (no. s ) decreased by 31% when burial depth in the sediments was increased from 4 to 7 cm; most N. radiata are < 4 cm deep, and most M. balthica eaten by eiders are probably 7 to 10 cm deep. Considering energy content, digestibility, and intake rates at these burial depths for 1200 clams m -2 , energy assimilated was 14 to 19% higher for N. radiata than M. calcarea of the same length classes. However, larger M. calcarea yielded 58% higher intake of assimilable energy than smaller N. radiata. These patterns emphasize that relative foraging value depends strongly on size (age) structures of different prey populations, which vary with recruitment, growth, and mortality in different seasons and years. Our results show that impacts of long-term benthic change on eiders depend not only on shifts in total clam abundance, but also on species differences in digestibility, size structure, and size-dependent nutrient content and burial depth.

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“…Variability in strength and the position of the low is important to the Bering Sea through its impact on circulation, surface heat fluxes, mixed layer depths, and the extent of ice cover, all of which influence the rich biological resources of the sea (Wooster and Hollowed 1995;Wyllie-Echeverria and Wooster 1998;Hollowed et al 2001;Benson and Trites 2002). Because the oceanic circulation over the shelf region of the eastern Bering Sea is so sluggish, the winter atmospheric circulation is considered to be the primary driving force behind the interannual variability of the oceanic environment of the region (Niebauer et al 1999;Stabeno et al 2001).…”

Section: Introductionmentioning

confidence: 99%

The Aleutian Low and Winter Climatic Conditions in the Bering Sea. Part I: Classification*

2005

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The Aleutian low is examined as a primary determinant of surface air temperature (SAT) variability in the Bering Sea during the winter [December-January-February-March (DJFM)] months. The Classification and Regression Tree (CART) method is used to classify five types of atmospheric circulation for anomalously warm months (W1-W5) and cold months (C1-C5). For the Bering Sea, changes in the position of the Aleutian low are shown to be more important than changes in its central pressure. The first two types, W1 and C1, account for 51% of the "warm" and 37% of the "cold" months. The W1-type pattern is characterized by the anomalously deep Aleutian low shifted west and north of its mean position. In this situation, an increased cyclonic activity occurs in the western Bering Sea. The C1-type pattern represents a split Aleutian low with one center in the northwestern Pacific and the other in the Gulf of Alaska. The relative frequency of the W1 to C1 types of atmospheric circulation varies on decadal time scales, which helps to explain the predominance of fluctuations on these time scales in the weather of the Bering Sea. Previous work has noted the prominence of multidecadal variability in the North Pacific. The present study finds multidecadal variations in frequencies of the W3 and C3 patterns, both of which are characterized by increased cyclonic activity south of 51°N. In general, the CART method is found to be a suitable means for characterizing the wintertime atmospheric circulation of the North Pacific in terms of its impact on the Bering Sea. The results show that similar pressure anomaly patterns for the North Pacific as a whole can actually result in different conditions for the Bering Sea, and that similar weather conditions in the Bering Sea can arise from decidedly different large-scale pressure patterns.

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Year‐to‐year variations in Bering Sea ice cover and some consequences for fish distributions

Cited by 201 publications

References 19 publications

Seasonal distribution of dissolved inorganic carbon and net community production on the Bering Sea shelf

Seasonal distribution of dissolved inorganic carbon and net community production on the Bering Sea shelf

Effects of clam species dominance on nutrient and energy acquisition by spectacled eiders in the Bering Sea

The Aleutian Low and Winter Climatic Conditions in the Bering Sea. Part I: Classification*

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