In Greenland, tidewater glaciers discharge turbid subglacial freshwater into fjords, forming a plume near the calving front. To elucidate the effects of this discharge on nutrient and dissolved inorganic carbon transport to the surface in these fjords, we conducted observational studies on Bowdoin Glacier and in its fjord in northwestern Greenland during the summer of 2016. Our results provide evidence of macronutrient and dissolved inorganic carbon transport from deep in the fjord to the surface in front of the glacier. This transport is driven by plume formation resulting from subglacial freshwater discharge and subsequent upwelling along the glacier calving front. The plume water is a mixture of subglacial freshwater and entrained fjord water. The fraction of glacial meltwater in the plume water is ~14% when it reaches the surface. The plume water is highly turbid because it contains substantial amounts of sediment derived from subglacial weathering. After reaching the surface, the plume water submerges and forms a turbid subsurface layer below fresher surface water at densities of 25.0 to 26.5 σθ. Phytoplankton blooms (~6.5 μg/L chlorophyll a) were observed near the boundary between the fresher surface and turbid subsurface layers. The bloom was associated with a strong upward NO3− + NO2− flux, which was caused by the subduction of plume water. Our study demonstrated that the subglacial discharge and plume formation at the front of Bowdoin Glacier play a key role in the availability of nutrients and the subsequent growth of phytoplankton in the glaciated fjord.

Calving glaciers are rapidly retreating in many regions under the influence of ice‐water interactions at the glacier front. In contrast to the numerous researches conducted on fjords in front of tidewater glaciers, very few studies have been reported on lakes in which freshwater calving glaciers terminate. To better understand ice‐water interactions at the front of freshwater calving glaciers, we measured lakewater temperature, turbidity, and bathymetry near Glaciar Perito Moreno, Upsala, and Viedma, large calving glaciers of the Southern Patagonia Icefield. The thermal structures of these lakes were significantly different from those reported in glacial fjords. There was no indication of upwelling subglacial meltwater; instead, turbid and cold glacial water discharge filled the region near the lake bottom. This was because water density was controlled by suspended sediment concentrations rather than by water temperature. Near‐surface wind‐driven circulation reaches a depth of ~180 m, forming a relatively warm isothermal layer (mean temperature of ~5–6°C at Perito Moreno, ~3–4°C at Upsala, and ~6–7°C at Viedma), which should convey heat energy to the ice‐water interface. However, the deeper part of the glacier front is in contact with stratified cold water, implying a limited amount of melting there. In the lake in front of Glaciar Viedma, the region deeper than 120 m was filled entirely with turbid and very cold water at pressure melting temperature. Our results revealed a previously unexplored thermal structure of proglacial lakes in Patagonia, suggesting its importance in the subaqueous melting of freshwater calving glaciers.

Liver and kidney glutathione S-transferase (GST) activities to 1,2-dichloro-4-nitrobenzene (DCNB) as a substrate (GST-D activities) were measured in 280 dogs from five different breeders, and significant individual differences in this activity were observed in both organs. Interestingly, 34 out of the 280 dogs (i.e. 12.1%) were those in which liver GST-D activities were less than 10 nmol/min per mg cytosolic protein, "low GST dogs", and the other dogs were classified as "middle" and "high" GST dogs for which the liver GST-D activities were 10-80 and >80 nmol/min per mg protein, respectively, and occurred at similar percentages (41.4% for the middle GST dog and 46.4% for the high GST dog). Furthermore, the existence of the low GST dogs was not limited to one particular breeder. There was a good correlation (r=0.910) between the liver and kidney GST-D activities, showing low activity in not only the liver but also the kidney in the low GST dogs. Although liver GST activity to 1-chloro-2,4-dinitrobenzene as a substrate (GST-C activity), catalyzed by various GST isozymes in dogs, was significantly correlated with liver GST-D activity, GST-C activity showed more than 450 nmol/min per mg protein even in the low GST dogs. There was no significant difference in cytochrome P450 content, 7-ethoxycoumarin O-deethylase activity or UDP-glucuronosyltransferase activity to p-nitrophenol as a substrate between low GST dogs and the other dogs. Finally, remarkably high plasma concentrations of DCNB were observed in the low GST dogs after single doses of DCNB at 5 or 100 mg/kg. The individual differences in GST-D activity are probably attributable to the content and/or activity of the theta class GST isozyme Yd(f)Yd(f) since it has been reported that glutathione conjugation of DCNB is specifically catalyzed by GSTYd(f)Yd(f) in dogs. In conclusion, we identified a number of low GST dogs in which the GST-D activities were not observed either in vivo or in vitro. The feasibility of using a single low dose of DCNB to phenotype dogs based on GST-D activity was confirmed. It was also suggested that low GST dogs have high susceptibility, including unexpected toxicity or abnormal exposure, to chemicals metabolized by GSTYd(f)Yd(f).

In Greenland, tidewater glaciers discharge turbid subglacial freshwater into fjords, forming plumes near the calving fronts, and these areas serve as an important foraging habitat for seabirds. To investigate the effect of subglacial discharge on the foraging assemblages of surface feeders and divers in a glacial fjord, we conducted boat-based seabird surveys, near-surface zooplankton samplings, and hydrographic measurements at Bowdoin Fjord, northwestern Greenland in July. Foraging surface feeders (black-legged kittiwake Rissa tridactyla, glaucous gull Larus hyperboreus, and northern fulmar Fulmarus glacialis) aggregated within a plume-affected area in front of Bowdoin Glacier. This area was characterized by highly turbid subglacial meltwater and abundant large-sized zooplankton including Calanus hyperboreus, chaetognaths, and ctenophores near the surface. Surface feeders fed on these aggregated prey presumably transported to the surface by strong upwelling of subglacial meltwater. In contrast, divers (little auk Alle alle, thick-billed murre Uria lomvia, and black guillemot Cepphus grylle) foraged outside the fjord, where turbidity was low and jellyfish and Calanus copepods dominated under the influence of Atlantic water. Our study indicates spatial segregation between surface feeders and divers in a glacial fjord; surface feeders are not hindered by turbidity if taking prey at the surface, whereas divers need clear water.

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