Hydrographic conditions during the 2002 SBI process experiments

Codispoti, Louis A; Flagg, Charles N.; Kelly, Vincent; Swift, James H.

doi:10.1016/j.dsr2.2005.10.007

Cited by 197 publications

(181 citation statements)

References 53 publications

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“…The UHL extends to around 150 m in the Canada Basin with salinity between 31 and 33. The salinity of the LHL ranges between 34.2 and 34.6 in Beaufort Sea [Codispoti et al, 2005]. The PML and the UHL are mixtures of Pacific water, freshwater from rivers, precipitation, sea ice meltwater, and brine water from sea ice formation; the LHL arises through mixing between the Atlantic layer and the UHL as these waters circulate around the Arctic Ocean.…”

Section: Methodsmentioning

confidence: 99%

“…The temperature of these layers is close to the freezing point; the vertical density gradient is maintained by salinity differences. The halocline layer is further subdivided into the upper halocline layer (UHL) or the Pacific halocline layer and the lower halocline layer (LHL) or Atlantic halocline layer [Codispoti et al, 2005;Steele et al, 2004]. The UHL extends to around 150 m in the Canada Basin with salinity between 31 and 33.…”

Section: Methodsmentioning

confidence: 99%

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Calcium carbonate saturation states in the waters of the Canadian Arctic Archipelago and the Labrador Sea

Azetsu-Scott¹,

Clarke²,

Falkner³

et al. 2010

J. Geophys. Res.

110

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Ocean acidification is predicted to occur first in polar oceans. We investigated the saturation state of waters with respect to calcite (Ωcal) and aragonite (Ωarg) in six sections along an Arctic outflow pathway through the Canadian Arctic Archipelago (CAA) and into the northwestern Atlantic using dissolved inorganic carbon and total alkalinity measurements from 2003 to 2005. The study area, a key region connecting the Arctic and the North Atlantic, includes Smith Sound, Barrow Strait, Baffin Bay, Davis Strait, Hudson Strait, and the Labrador Sea. The average Ωarg in the Arctic outflow was 1.18 ± 0.17 in Barrow Strait and 1.31 ± 0.14 in Smith Sound, with areas where Ωarg < 1. The Arctic outflow through the CAA has a high content of Pacific waters, which have a low saturation state. These waters can be traced along the western Baffin Bay to Davis Strait. South of Davis Strait, this outflow is modified by mixing with slope and offshore waters of Atlantic origin and with the outflow from Hudson Strait. Despite the mixing, low saturation state water can still be identified on the southern Labrador Shelf. The aragonite saturation horizon is found at ∼150 m in Barrow Strait; at 200 m in Baffin Bay, Davis Strait, and Hudson Strait; and at 2300 m in the Labrador Sea. This study provides baseline data of the saturation states for the waters of the CAA and the northwest Atlantic. It also illustrates the downstream evolution of low saturation state Arctic outflow in the northwest Atlantic.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Calcium carbonate saturation states in the waters of the Canadian Arctic Archipelago and the Labrador Sea

Azetsu-Scott¹,

Clarke²,

Falkner³

et al. 2010

J. Geophys. Res.

110

View full text Add to dashboard Cite

show abstract

“…The water masses comprise the polar mixed layer (PML, salinity < 31, 0-50 m depth), which is influenced by fresh waters from the rivers and melting sea ice, the upper Pacific halocline (salinity: 31-33, 50-200 m depth) associated with a prominent nutrient maximum at salinities of ∼ 33, the lower Atlantic halocline (200-275 m depth) and the relatively warm (> 0 • C) and salty deep waters of Atlantic origin (salinity > 34.5, > 275 m depth). The main hydrodynamic and trophic features for the different zones are described in more detail by Codispoti et al (2005) and by Matsuoka et al (2012). A particularly important feature of the Arctic Ocean is the strong perennial cold halocline, which isolates surface waters (and sea ice) from warm and salty Atlantic waters.…”

Section: Study Area and Samplingmentioning

confidence: 99%

Carbon sources in suspended particles and surface sediments from the Beaufort Sea revealed by molecular lipid biomarkers and compound-specific isotope analysis

et al. 2013

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Molecular lipid biomarkers (hydrocarbons, alcohols, sterols and fatty acids) and compound-specific isotope analysis of suspended particulate organic matter (SPM) and surface sediments of the Mackenzie Shelf and slope (southeast Beaufort Sea, Arctic Ocean) were studied in summer 2009. The concentrations of the molecular lipid markers, characteristic of known organic matter sources, were grouped and used as proxies to evaluate the relative importance of fresh algal, detrital algal, fossil, C₃ terrestrial plants, bacterial and zooplankton material in the organic matter (OM) of this area. Fossil and detrital algal contributions were the major fractions of the freshwater SPM from the Mackenzie River with ~34% each of the total molecular biomarkers. Fresh algal, C₃ terrestrial, bacterial and zooplanktonic components represented much lower percentages, 17, 10, 4 and <1%, respectively. In marine SPM from the Mackenzie slope, the major contributions were fresh and detrital algal components (>80%), with a minor contribution of fossil and C₃ terrestrial biomarkers. Characterization of the sediments revealed a major sink of refractory algal material mixed with some fresh algal material, fossil hydrocarbons and a small input of C₃ terrestrial sources. In particular, the sediments from the shelf and at the mouth of the Amundsen Gulf presented the highest contribution of detrital algal material (60–75%), whereas those from the slope contained the highest proportion of fossil (40%) and C₃ terrestrial plant material (10%). Overall, considering that the detrital algal material is marine derived, autochthonous sources contributed more than allochthonous sources to the OM lipid pool. Using the ratio of an allochthonous biomarker (normalized to total organic carbon, TOC) found in the sediments to those measured at the river mouth water, we estimated that the fraction of terrestrial material preserved in the sediments accounted for 30–40% of the total carbon in the inner shelf sediments, 17% in the outer shelf and Amundsen Gulf and up to 25% in the slope sediments. These estimates are low compared to other studies conducted 5–20 yr earlier, and they support the increase in primary production during the last decade mainly because of the increase in the number of ice-free days and due to the strength and persistence of winds favouring upwelling

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“…However, the nitrate concentration uniformly reaches 10-20 µM at the onset of the growth season, even in the surface water, as a result of strong vertical mixing in both the Chukchi and Bering shelves (e.g. Sambrotto et al, 1986;Codispoti et al, 2005), which is enough to support a large open-water and/or underice bloom. Thus, our findings suggest that the length of the open-water period plays a significant role in controlling the APP in the study region, especially in the northern Chukchi shelf (Fig.…”

Section: Factors Controlling Annual Net Primary Productionmentioning

confidence: 99%

Influence of timing of sea ice retreat on phytoplankton size during marginal ice zone bloom period on the Chukchi and Bering shelves

et al. 2016

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Abstract. The size structure and biomass of a phytoplankton community during the spring bloom period can affect the energy use of higher-trophic-level organisms through the predator-prey body size relationships. The timing of the sea ice retreat (TSR) also plays a crucial role in the seasonally ice-covered marine ecosystem, because it is tightly coupled with the timing of the spring bloom. Thus, it is important to monitor the temporal and spatial distributions of a phytoplankton community size structure. Prior to this study, an ocean colour algorithm was developed to derive phytoplankton size index F L , which is defined as the ratio of chlorophyll a (chl a) derived from cells larger than 5 µm to the total chl a, using satellite remote sensing for the Chukchi and Bering shelves. Using this method, we analysed the pixel-bypixel relationships between F L during the marginal ice zone (MIZ) bloom period and TSR over the period of 1998-2013. The influences of the TSR on the sea surface temperature (SST) and changes in ocean heat content ( OHC) during the MIZ bloom period were also investigated. A significant negative relationship between F L and the TSR was widely found in the shelf region during the MIZ bloom season. However, we found a significant positive (negative) relationship between the SST ( OHC) and TSR. Specifically, an earlier sea ice retreat was associated with the dominance of larger phytoplankton during a colder and weakly stratified MIZ bloom season, suggesting that the duration of the nitrate supply, which is important for the growth of large-sized phytoplankton in this region (i.e. diatoms), can change according to the TSR. In addition, under-ice phytoplankton blooms are likely to occur in years with late ice retreat, because sufficient light for phytoplankton growth can pass through the ice and penetrate into the water columns as a result of an increase in solar radiation toward the summer solstice. Moreover, we found that both the length of the ice-free season and the annual median of F L positively correlated with the annual net primary production (APP). Thus, both the phytoplankton community composition and growing season are important for the APP in the study area. Our findings showed a quantitative relationship between the interannual variability of F L , the TSR, and the APP, which suggested that satellite remote sensing of the phytoplankton community size structure is suitable to document the impact of a recent rapid sea ice loss on the ecosystem of the study region.

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Hydrographic conditions during the 2002 SBI process experiments

Cited by 197 publications

References 53 publications

Calcium carbonate saturation states in the waters of the Canadian Arctic Archipelago and the Labrador Sea

Calcium carbonate saturation states in the waters of the Canadian Arctic Archipelago and the Labrador Sea

Carbon sources in suspended particles and surface sediments from the Beaufort Sea revealed by molecular lipid biomarkers and compound-specific isotope analysis

Influence of timing of sea ice retreat on phytoplankton size during marginal ice zone bloom period on the Chukchi and Bering shelves

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