Oxygen isotopic composition of bottom seawater and tunicate cellulose used as indicators of water masses in the northern Bering and Chukchi Seas

Abstract

Oxygen isotopic composition of bottom seawater and tunicate cellulose were used as short‐term and long‐term indicators, respectively, of water‐mass characteristics in the northern Bering and Chukchi Seas. Oxygen isotopic composition of northeastern Bering Sea waters is influenced by Yukon River inflows of 18O‐depleted continental water mixing with relatively 18O‐enriched waters contributed by the Anadyr Current. Tunicate cellulose sampled under Alaska coastal water is more depleted in 18O than that collected under Bering shelf and Anadyr waters, which reflects the oxygen isotopic composition of these waters. Tunicate cellulose collected under the mixed Bering shelf water displays intermediate δ18O values. Oxygen isotopic analyses of bottom seawater were used to determine the spatial location and influence of continental and coastal‐derived precipitation and of sea‐ice formation on water‐mass structure on the continental shelf of the northern Bering and Chukchi Seas. Results indicate that the oxygen isotopic composition of tunicate cellulose, averaged over multiple seasons, may serve as a long‐term biochemical indicator of water‐mass patterns in ice‐covered polar regions where continuous sampling is impractical.

Oxygen isotope ratio, barium and salinity in waters around the North American coast from the Pacific to the Atlantic: Implications for freshwater sources to the Arctic throughflow

“…The absence of an apparent influence of sea ice meltwater (Fig. 5a) differs from past observations in the same region that revealed both downward and upward deviations from the linear regression of S-␦ 18 O (Grebmeier et al, 1990;Cooper et al, 1997;Clement et al, 2004;Schmidt et al, 1999)(upward and downward deviations indicate mixing with sea ice meltwater (ϳ Ϫ2‰) and brine injection, respectively (Strain and Tan, 1993;Melling and Moore, 1995;Yamamoto et al, 2001;).…”

Late winter water column and sea ice conditions in the northern Bering Sea

“…Salinities at or approaching 33 psu are likely to be influenced by brine injection [ Schumacher et al , 1983]. This distinction is also based on previous results that show that typical salinities (during summer without the influence of sea ice processes) are approximately 32.5 psu or less [ Grebmeier et al , 1990; Grebmeier , 1993; Grebmeier and Cooper , 1995]. Generally, bottom water salinities were higher in March 2001 (mean = 32.59 ± 0.21 SD) than in April 1999 (mean = 32.32 ± 0.38 SD).…”

The nutrient, salinity, and stable oxygen isotope composition of Bering and Chukchi Seas waters in and near the Bering Strait

“…Bering Sea/Strait Nutrient Analyses onboard autoanalyzer onboard autoanalyzer onboard autoanalyzer shipboard and lab analyses from frozen samples lab autoanalyzed from frozen samples lab autoanalyzed from frozen samples waters in the Bering Sea and limited sampling in the Chukchi Sea [Grebmeier et al, 1990;Grebmeier and Cooper, 1995]. The present data are derived from samples collected on several cruises and provide a description of the 5180 values of waters of the Bering and Chukchi Seas.…”