Coastal ocean ecosystems are at risk from global warming-induced retreat of marine-terminating (tidewater) glaciers. Increased phytoplankton growth near tidewater glaciers has been observed in a range of locations, but it remains unclear exactly how these systems serve to elevate production. Recent work has suggested that both glacial meltwater and upwelled deeper marine waters brought to the surface by buoyant submarine discharge plumes may provide polar phytoplankton with essential nutrients throughout the summer. To test this hypothesis, we conducted a novel incubation experiment in Ausuittuq (Grise Fiord), Nunavut during summer 2021 to uncover how Canadian Arctic Archipelago (CAA) phytoplankton respond to different glacier-derived nutrient sources. Here, phytoplankton were supplied with glacial meltwater and/or deep seawater representing meltwater and upwelled nutrients respectively, and were monitored for chlorophyll a, nutrient consumption, and protein expression patterns. Phytoplankton exposed to deep water exhibited chlorophyll a concentrations that were four times higher than treatments exposed to meltwater only. These results suggest that the success of CAA phytoplankton near tidewater glaciers is largely due to upwelled macronutrients. Protein expression including meta-proteomics and Rubisco measurements of specific phytoplankton groups reveal molecular responses to these glacier-driven changes and shed light on how future tidewater glacier retreat is likely to impact primary producers in future climate warming scenarios. 

Primary Presenter: Patrick White, University of Alberta (pwhite1@ualberta.ca)

Authors:

Patrick White, University of Alberta  (pwhite1@ualberta.ca)

Maya Bhatia, University of Alberta  (mbhatia@ualberta.ca)

Maria Cavaco, University of Alberta  (cavaco@ualberta.ca)

Stephanie Waterman, University of British Columbia  (swaterman@eoas.ubc.ca)

Terry Noah, Ausuittuq Adventures  (TerryNoah_46@hotmail.com)

Elden Rowland, Dalhousie University  (Elden.Rowland@Dal.Ca)

Loay Jabre, Dalhousie University  (Loay.Jabre@dal.ca)

Margaret Mars Brisbin, Woods Hole Oceanographic Institution  (mmarsbrisbin@whoi.edu)

Arianna Krinos, MIT-WHOI Joint Program in Oceanography/Applied Ocean Science and Engineering   (akrinos@whoi.edu)

Harriet Alexander, Woods Hole Oceanographic Institution  (halexander@whoi.edu)

Travis Mellett, Universtiy of Washington  (tmellett@uw.edu)

Randie Bundy, Universtiy of Washington  (rbundy@uw.edu)

Erin Bertrand, Dalhousie University  (erin.bertrand@dal.ca)