Contrasting assemblages of seabirds in the subglacial meltwater plume and oceanic water of Bowdoin Fjord, northwestern Greenland

Abstract

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.

Iron Supply by Subglacial Discharge Into a Fjord Near the Front of a Marine‐Terminating Glacier in Northwestern Greenland

“…In summer, Bowdoin Glacier discharges turbid subglacial water into the fjord, forming a buoyant plume near the calving front (Jouvet et al, 2018). The impact of the subglacial discharge on the marine ecosystem in Bowdoin Fjord has been reported recently by Kanna et al (2018), Naito et al (2019), and Nishizawa et al (2019).…”

“…Glacial fjords in Greenland are characterized by high productivity, represented by a high phytoplankton biomass as well as a high density of fish, seabirds, and marine mammals (Laidre et al, 2016; Meire et al, 2017; Nishizawa et al, 2019). The production of phytoplankton biomass within fjords shows seasonal patterns with a primary peak in spring, followed by a secondary peak in summer (Juul‐Pedersen et al, 2015).…”

Toward the Acoustic Detection of Two‐Phase Flow Patterns and Helmholtz Resonators in Englacial Drainage Systems

“…The most plausible explanation for the main LF sound generation mechanism in a crevasse is self-excited flow pulsation due to the instability of two-phase flow (air and water) in a vertical drainage conduit. Engineers and physicists have long studied noise and vibration sources in pipe and conduit networks (e.g., Blake, 2017;Naudascher & Rockwell, 2005), with two-phase gas-liquid flow known for its challenging complexity, which arises from an interaction between the phases. However, there are few data on the acoustic features and mechanisms of the flow-induced pulsating sounds identified here.…”

Automated Detection of Marine Glacier Calving Fronts Using the 2-D Wavelet Transform Modulus Maxima Segmentation Method

“…patterns [28], [37]. Ice mass loss from Greenland's glaciers, ice caps, and ice sheet contributes ∼43% to the contemporary global sea level rise [30].…”