Oxygen fluxes beneath Arctic land-fast ice and pack ice: towards estimates of ice productivity

• DOI: 10.1007/s00300-018-2350-1
• Publication Date: 2018-06-12T08:48:31Z
• Authors: Karl M. Attard; Dorte H. Søgaard; Judith Piontek; Benjamin A. Lange; Christian Katlein; Heidi L. Sørensen; Daniel F. McGinnis; Lorenzo Rovelli; Søren Rysgaard; Frank Wenzhöfer; Ronnie N. Glud
• Keywords: Meltwater

Sea-ice ecosystems are among the most extensive of Earth’s habitats; yet its autotrophic and heterotrophic activities remain poorly constrained. We employed in situ aquatic eddy-covariance (AEC) O2 flux method laboratory incubation techniques (H14CO3−, [3H] thymidine leucine) to assess productivity Arctic sea-ice using different methods, conditions ranging from land-fast ice during winter, pack within central Ocean summer. Laboratory tracer measurements resolved rates bacterial C demand 0.003–0.166 mmol m−2 day−1 primary 0.008–0.125 for floes. Pack was overall net (0.002–0.063 day−1), whereas winter (− 0.155 day−1). AEC an uptake by bottom-ice environment, ~ − 2 under to~ 6 summer ice. Flux O2-deplete meltwater changes water flow velocity masked potential biological-mediated activity. estimates were only possible at one study location. Here, 1.3 ± 0.9 day−1, much larger than concurrent (0.03 indicate that algal production importance marine could be underestimated traditional approaches. Given careful interpretation with further development, technique represents a promising new tool assessing oxygen dynamics ice-covered regions.