Amino acid δ13C and δ15N fingerprinting of sea ice and pelagic algae in Canadian Arctic and Subarctic Seas

The on-going decline in Arctic sea ice represents a significant loss of habitat for algae, which are major contributor to primary production the Arctic. Data on algal is limited due difficulties both accessing sea-ice and sampling under-ice algae. Compound-specific isotope analysis (CSIA) amino acids (AAs) emerging as powerful tool trace element origins biogeochemical processes marine food webs may address knowledge gaps productivity dynamics. Here we measured δ 13 C-AA 15 N-AA natural communities pelagic algae collected from regions offshore Labrador Nunavut, Canada. Significant difference patterns between was observed different size classes. This further supported by multivariate analyses based normalized C essential (EAAs), demonstrated clear separation Beta (β) values trophic position (TP) calculated N Glutamic Acid Phenylalanine (Phe) ∑V parameter microbial resynthesis indicated slightly higher heterotrophic biomass samples compared cultured samples. finding consistent with Phe-normalized Alanine Threonine, provided better separations ice/pelagic other end-member groups. Overall, our study provides first insights into potential differences suggests carbon be distinguished sources using CSIA-AA approach. These observations highlight estimate proportional contributions export efficiency benthic-pelagic coupling polar environments.