ALBERT

Description: This is the first high temporal-resolution study in Disko Bay covering population dynamics, grazing, reproduction, and biochemical composition of 3 dominating copepod species (Calanus finmarchicus, C. glacialis and C. hyperboreus) from late winter to midsummer in 2008. C. finmarchicus and C. glacialis ascended to the surface layer at the onset of the spring phytoplankton bloom, followed by C. hyperboreus 2 wk later. C. finmarchicus spawning occurred during the bloom and postbloom period, partially fueled by wax esters. C. glacialis commenced spawning before the bloom, yet it was greatly stimulated when food became available. However, feeding and reproduction was terminated after the main bloom despite the presence of food. In terms of feeding, this was also the strategy for C. hyperboreus. Between pre-bloom and post-bloom, C. finmarchicus showed an increase in carbon, nitrogen, and phospholipid content but a decrease in total lipid content. This was likely the result of protein synthesis, oocyte maturation, and spawning fueled by wax esters and by feeding. C. glacialis showed a similar pattern, although with an increasing total lipid content from pre-bloom to post-bloom, and an increasing wax ester and decreasing phospholipid content after reproduction was terminated. C. hyperboreus showed greatly increased content of carbon, nitrogen, and all lipid classes between the pre- and post-bloom periods. Hence, C. finmarchicus commenced feeding and spawning at the onset of the bloom and continued throughout the remaining study period. Both C. glacialis and C. hyperboreus females refueled their storage lipids (wax esters) during the bloom and post-bloom period, suggesting that they may spawn in an additional year.

Description: This study describes differences in plankton community structure and in chemical and physical gradients between the offshore West Greenland Current system and inland regions close to the Greenland Ice Sheet during the post-bloom in Godthabsfjorden (64° N, 51° W). The offshore region had pronounced vertical mixing, with centric diatoms and Phaeocystis spp. dominating the phytoplankton, chlorophyll (chl) a (0.3 to 3.9 µg/l) was evenly distributed and nutrients were depleted in the upper 50 m. Ciliates and heterotrophic dinoflagellates constituted equal parts of the protozooplankton biomass. Copepod biomass was dominated by Calanus spp. Primary production, copepod production and the vertical flux were high offshore. The water column was stratified in the fjord, causing chl a to be concentrated in a thin sub-surface layer. Nutrients were depleted above the pycnocline, and Thalassiosira spp. dominated the phytoplankton assemblage close to the ice sheet. Dinoflagellates dominated the protozooplankton biomass, whereas copepod biomass was low and was dominated by Pseudocalanus spp. and Metridia longa. Primary production was low in the outer part of the fjord but considerably higher in the inner parts of the fjord. Copepod production was exceeded by protozooplankton production in the fjord. The results of both physical/chemical factors and biological parameters suggest separation of offshore and fjord systems.

Description: Photogrammetric reanalysis of 1985 aerial photos has revealed substantial submarine melting of the floating ice tongue of Jakobshavn Isbrae, west Greenland. The thickness of the floating tongue determined from hydrostatic equilibrium tapers from ~940 m near the grounding zone to ~600 m near the terminus. Feature tracking on orthophotos shows speeds on the July 1985 ice tongue to be nearly constant (~18.5 m/d), indicating negligible dynamic thinning. The thinning of the ice tongue is mostly due to submarine melting with average rates of 228 ± 49 m/yr (0.62 ± 0.13 m/d) between the summers of 1984 and 1985. The cause of the high melt rate is the circulation of warm seawater (thermal forcing of up to 4.2°C) beneath the tongue with convection driven by the substantial discharge of subglacial freshwater from the grounding zone. We believe that this buoyancy-driven convection is responsible for a deep channel incised into the sole of the floating tongue. A dramatic thinning, retreat, and speedup began in 1998 and continues today. The timing of the change is coincident with a 1.1°C warming of deep ocean waters entering the fjord after 1997. Assuming a linear relationship between thermal forcing and submarine melt rate, average melt rates should have increased by ~25% (~57 m/yr), sufficient to destabilize the ice tongue and initiate the ice thinning and the retreat that followed.

Description: Here we present results from a synoptic survey of the pan‐east Greenland coastal system from the entrance of fjords at Cape Farewell (59°N) to Kaiser Franz Josef Fjord (73°N). Using conductivity‐temperature‐depth (CTD) profiles and water isotopes (δ18O, δ2H) sampling, we aim to describe the spatial distribution of water masses and source water fractions along east Greenland and their link to proglacial fjords. This is a hydrographic dataset containing CTD cast from the HDMS Knud Rasmussen cruise KR_2021 that took place from 10-26 August 2021 and was part of the research project Greenland Gradients led by Rysgaard, Sören. On each station, vertical CTD (SBE19plus) casts were made down to 500 m water depth or close to the sea floor if shallower. Temperature and salinity data were derived from these CTD profiles. Temperature is reported as potential temperature (ITS-90, degree C).

Description: The NEG2017 cruise took place from 23 August 2017 to 11 September 2017 was part of the Strategic Environmental program for Northeast Greenland with as its goal to provide environmental impact information pertaining to potential oil exploitation and oil spill response activities in the region. The cruise leader for NEG2017 was Eva Friis Møller.

Description: The NorthGreen2017 cruise took place directly after the first between 11 September 2017 and 1 October 2017. It aimed to collect data pertaining to hydroraphical and environmental changes on the shelf. The cruise leader for the NorthGreen2017 cruise was Marit-Solveig Seidenkrantz.

Description: Here we present results from a synoptic survey of the pan‐east Greenland coastal system from the entrance of fjords at Cape Farewell (59°N) to Kaiser Franz Josef Fjord (73°N). Using conductivity‐temperature‐depth (CTD) profiles and water isotopes (δ18O, δ2H) sampling, we aim to describe the spatial distribution of water masses and source water fractions along east Greenland and their link to proglacial fjords. This is a hydrographic dataset containing stable water isotopes 18O & 2H samples from the HDMS Knud Rasmussen cruise KR_2021 that took place from 10-26 August 2021 and was part of the research project Greenland Gradients led by Rysgaard, Sören. Samples for analysis of water isotopic were collected at 1, 5, 10, 20, 30, 50, 75, 100, 150, 200, 250, 500 m depth in the water column at each station. Stable isotopes of oxygen and hydrogen (16O, 18O, 1H, 2H) in water samples were determined using a Cavity Ringdown Spectrometer, L2130-i Isotopic sH20 (Picarro Inc., USA).

Description: The NorthGreen2017 cruise took place directly after the first between 11 September 2017 and 1 October 2017. It aimed to collect data pertaining to hydroraphical and environmental changes on the shelf. The cruise leader for the NorthGreen2017 cruise was Marit-Solveig Seidenkrantz.