PATTERNS OF RUBISCO CONCENTRATIONS IN GLACIERIZED AND NON-GLACIERIZED ENVIRONMENTS ACROSS JONES SOUND, NU

Abstract

Tidewater glaciers can enhance delivery of nutrients to the surface ocean. The Canadian Arctic Archipelago (CAA) has a high density of tidewater glaciers, but their influence on the marine environment, particularly phytoplankton, is understudied. Here we develop and apply a targeted metaproteomic approach to measure Rubisco concentrations in phytoplankton communities across Jones Sound, NU. Because Rubisco is the protein used for carbon fixation, we can estimate potential rates of primary production from these measurements. We found these estimates to be within expected ranges. We found that Rubisco produced by Chaetoceros (diatom) is higher at glacierized stations while Rubisco from Micromonas (Chlorophyta), is enhanced at non-glacierized sites. This suggests that future climate scenarios may favour smaller phytoplankton groups, like Micromonas, with downstream consequences for food webs and carbon cycling. This study broadens our understanding of the impact tidewater glaciers in the CAA, now and in a warmer future.